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Sample records for reported missense mutation

  1. Analyzing effects of naturally occurring missense mutations.

    Science.gov (United States)

    Zhang, Zhe; Miteva, Maria A; Wang, Lin; Alexov, Emil

    2012-01-01

    Single-point mutation in genome, for example, single-nucleotide polymorphism (SNP) or rare genetic mutation, is the change of a single nucleotide for another in the genome sequence. Some of them will produce an amino acid substitution in the corresponding protein sequence (missense mutations); others will not. This paper focuses on genetic mutations resulting in a change in the amino acid sequence of the corresponding protein and how to assess their effects on protein wild-type characteristics. The existing methods and approaches for predicting the effects of mutation on protein stability, structure, and dynamics are outlined and discussed with respect to their underlying principles. Available resources, either as stand-alone applications or webservers, are pointed out as well. It is emphasized that understanding the molecular mechanisms behind these effects due to these missense mutations is of critical importance for detecting disease-causing mutations. The paper provides several examples of the application of 3D structure-based methods to model the effects of protein stability and protein-protein interactions caused by missense mutations as well.

  2. Trafficking defects and loss of ligand binding are the underlying causes of all reported DDR2 missense mutations found in SMED-SL patients.

    Science.gov (United States)

    Ali, Bassam R; Xu, Huifang; Akawi, Nadia A; John, Anne; Karuvantevida, Noushad S; Langer, Ruth; Al-Gazali, Lihadh; Leitinger, Birgit

    2010-06-01

    Spondylo-meta-epiphyseal dysplasia (SMED) with short limbs and abnormal calcifications (SMED-SL) is a rare, autosomal recessive human growth disorder, characterized by disproportionate short stature, short limbs, short broad fingers, abnormal metaphyses and epiphyses, platyspondyly and premature calcifications. Recently, three missense mutations and one splice-site mutation in the DDR2 gene were identified as causative genetic defects for SMED-SL, but the underlying cellular and biochemical mechanisms were not explored. Here we report a novel DDR2 missense mutation, c.337G>A (p.E113K), that causes SMED-SL in two siblings in the United Arab Emirates. Another DDR2 missense mutation, c.2254C>T (p.R752C), matching one of the previously reported SMED-SL mutations, was found in a second affected family. DDR2 is a plasma membrane receptor tyrosine kinase that functions as a collagen receptor. We expressed DDR2 constructs with the identified point mutations in human cell lines and evaluated their localization and functional properties. We found that all SMED-SL missense mutants were defective in collagen-induced receptor activation and that the three previously reported mutants (p.T713I, p.I726R and p.R752C) were retained in the endoplasmic reticulum. The novel mutant (p.E113K), in contrast, trafficked normally, like wild-type DDR2, but failed to bind collagen. This finding is in agreement with our recent structural data identifying Glu113 as an important amino acid in the DDR2 ligand-binding site. Our data thus demonstrate that SMED-SL can result from at least two different loss-of-function mechanisms: namely defects in DDR2 targeting to the plasma membrane or the loss of its ligand-binding activity.

  3. Novel three missense mutations observed in Von Hippel-Lindau gene in a patient reported with renal cell carcinoma

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    Pasupuleti Santhosh Kumar

    2013-01-01

    Full Text Available Von Hippel-Lindau (VHL disease is an autosomal dominant hereditary cancer syndrome that predisposes to the development of a variety of benign and malignant tumors, especially cerebellar hemangioblastomas, retinal angiomas and clear-cell renal cell carcinomas (RCC. We have identified of VHL gene using immunohistochemistry in a patient who was diagnosed for RCC. In order to understand the involvement of mutation in the VHL gene exon 1 was amplified and sequenced (accession number: JX 401534. The sequence analysis revealed the presence of novel missense mutations c.194 C>T, c.239 G>A, c.278 G>A, c.319 C>G, c. 337 C > G leading to the following variations p.Ala 65 Val, p.Gly 80 Asp, p.Gly 93 Glu, p.Gln 107 Glu, p.Gln 113 Glu in the protein.

  4. Characterization of two novel missense mutations in the AQP2 gene causing nephrogenic diabetes insipidus.

    NARCIS (Netherlands)

    Iolascon, A.; Aglio, V.; Tamma, G.; D'Apolito, M.; Addabbo, F.; Procino, G.; Simonetti, M.C.; Montini, G.; Gesualdo, L.; Debler, E.W.; Svelto, M.; Valenti, G.

    2007-01-01

    Here, we report the aquaporin 2 (AQP2) mutational analysis of a patient with nephrogenic diabetes insipidus heterozygote due to two novel missense mutations. Direct sequencing of DNA in the male patient revealed that he was compound heterozygote for two mutations in the AQP2 gene: a thymine-to-adeni

  5. Dominant missense mutations in ABCC9 cause Cantu syndrome

    NARCIS (Netherlands)

    Harakalova, M.; van Harssel, J.J.; Terhal, P.A.; van Lieshout, S.; Duran, K.; Renkens, I.; Amor, D.J.; Wilson, L.C.; Kirk, E.P.; Turner, C.L.; Shears, D.; Garcia-Minaur, S.; Lees, M.M.; Ross, A.; Venselaar, H.; Vriend, G.; Takanari, H.; Rook, M.B.; van der Heyden, M.A.; Asselbergs, F.W.; Breur, H.M.; Swinkels, M.E.; Scurr, I.J.; Smithson, S.F.; Knoers, N.V.; van der Smagt, J.J.; Nijman, I.J.; Kloosterman, W.P.; van Haelst, M.M.; van Haaften, G.; Cuppen, E.

    2012-01-01

    Cantu syndrome is characterized by congenital hypertrichosis, distinctive facial features, osteochondrodysplasia and cardiac defects. By using family-based exome sequencing, we identified a de novo mutation in ABCC9. Subsequently, we discovered novel dominant missense mutations in ABCC9 in 14 of the

  6. Dominant missense mutations in ABCC9 cause Cantu syndrome.

    NARCIS (Netherlands)

    Harakalova, M.; Harssel, J.J. van; Terhal, P.A.; Lieshout, S. van; Duran, K.; Renkens, I.; Amor, D.J.; Wilson, L.C.; Kirk, E.P.; Turner, C.L.; Shears, D.; Garcia-Minaur, S.; Lees, M.M.; Ross, A.; Venselaar, H.; Vriend, G.; Takanari, H.; Rook, M.B.; Heyden, M.A. van der; Asselbergs, F.W.; Breur, H.M.; Swinkels, M.E.; Scurr, I.J.; Smithson, S.F.; Knoers, N.V.A.M.; Smagt, J.J. van der; Nijman, I.J.; Kloosterman, W.P.; Haelst, M.M. van; Haaften, G. van; Cuppen, E.

    2012-01-01

    Cantu syndrome is characterized by congenital hypertrichosis, distinctive facial features, osteochondrodysplasia and cardiac defects. By using family-based exome sequencing, we identified a de novo mutation in ABCC9. Subsequently, we discovered novel dominant missense mutations in ABCC9 in 14 of the

  7. Rabson Mendenhall Syndrome caused by a novel missense mutation.

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    Sinnarajah, Krishnapradeep; Dayasiri, M B K C; Dissanayake, N D W; Kudagammana, S T; Jayaweera, A H H M

    2016-01-01

    Rabson Mendenhall syndrome is a rare endocrine condition characterized by severe insulin resistance and hyperglycemia. It occurs due to mutations in the insulin receptor gene. Few mutations which are associated with Rabson Mendenhall syndrome have been identified and reported in the past. The management of this condition is extremely challenging and will need multi-disciplinary approach. An 11 year old boy presented with polyuria and polydipsia. He was noted to have coarse facies, severe acanthosis nigricans, hypertrichosis, retarded growth and developmental delay. Investigations revealed severe hyperglycemia which was poorly responsive to high doses of insulin. A diagnosis of Rabson Mendenhall syndrome was suspected based on his physical characteristics in the presence of insulin resistance. Genetic studies revealed a homozygous missense mutation in the Insulin receptor gene confirming the diagnosis of Rabson Mendenhall syndrome. This is a novel mutation which has not been reported previously. Rabson Mendenhall syndrome should be suspected in a patient with characteristic physical features, severe hyperglycemia and insulin resistance. The genetic studies will not only confirm the diagnosis but also will help in counselling. Wider collaboration is needed to identify definitive treatment options for managing this rare condition.

  8. HER2 missense mutations have distinct effects on oncogenic signaling and migration

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    Zabransky, Daniel J.; Yankaskas, Christopher L.; Cochran, Rory L.; Wong, Hong Yuen; Croessmann, Sarah; Chu, David; Kavuri, Shyam M.; Red Brewer, Monica; Rosen, D. Marc; Dalton, W. Brian; Cimino-Mathews, Ashley; Cravero, Karen; Button, Berry; Kyker-Snowman, Kelly; Cidado, Justin; Erlanger, Bracha; Parsons, Heather A.; Manto, Kristen M.; Bose, Ron; Lauring, Josh; Arteaga, Carlos L.; Konstantopoulos, Konstantinos; Park, Ben Ho

    2015-01-01

    Recurrent human epidermal growth factor receptor 2 (HER2) missense mutations have been reported in human cancers. These mutations occur primarily in the absence of HER2 gene amplification such that most HER2-mutant tumors are classified as “negative” by FISH or immunohistochemistry assays. It remains unclear whether nonamplified HER2 missense mutations are oncogenic and whether they are targets for HER2-directed therapies that are currently approved for the treatment of HER2 gene-amplified breast cancers. Here we functionally characterize HER2 kinase and extracellular domain mutations through gene editing of the endogenous loci in HER2 nonamplified human breast epithelial cells. In in vitro and in vivo assays, the majority of HER2 missense mutations do not impart detectable oncogenic changes. However, the HER2 V777L mutation increased biochemical pathway activation and, in the context of a PIK3CA mutation, enhanced migratory features in vitro. However, the V777L mutation did not alter in vivo tumorigenicity or sensitivity to HER2-directed therapies in proliferation assays. Our results suggest the oncogenicity and potential targeting of HER2 missense mutations should be considered in the context of cooperating genetic alterations and provide previously unidentified insights into functional analysis of HER2 mutations and strategies to target them. PMID:26508629

  9. HER2 missense mutations have distinct effects on oncogenic signaling and migration.

    Science.gov (United States)

    Zabransky, Daniel J; Yankaskas, Christopher L; Cochran, Rory L; Wong, Hong Yuen; Croessmann, Sarah; Chu, David; Kavuri, Shyam M; Red Brewer, Monica; Rosen, D Marc; Dalton, W Brian; Cimino-Mathews, Ashley; Cravero, Karen; Button, Berry; Kyker-Snowman, Kelly; Cidado, Justin; Erlanger, Bracha; Parsons, Heather A; Manto, Kristen M; Bose, Ron; Lauring, Josh; Arteaga, Carlos L; Konstantopoulos, Konstantinos; Park, Ben Ho

    2015-11-10

    Recurrent human epidermal growth factor receptor 2 (HER2) missense mutations have been reported in human cancers. These mutations occur primarily in the absence of HER2 gene amplification such that most HER2-mutant tumors are classified as "negative" by FISH or immunohistochemistry assays. It remains unclear whether nonamplified HER2 missense mutations are oncogenic and whether they are targets for HER2-directed therapies that are currently approved for the treatment of HER2 gene-amplified breast cancers. Here we functionally characterize HER2 kinase and extracellular domain mutations through gene editing of the endogenous loci in HER2 nonamplified human breast epithelial cells. In in vitro and in vivo assays, the majority of HER2 missense mutations do not impart detectable oncogenic changes. However, the HER2 V777L mutation increased biochemical pathway activation and, in the context of a PIK3CA mutation, enhanced migratory features in vitro. However, the V777L mutation did not alter in vivo tumorigenicity or sensitivity to HER2-directed therapies in proliferation assays. Our results suggest the oncogenicity and potential targeting of HER2 missense mutations should be considered in the context of cooperating genetic alterations and provide previously unidentified insights into functional analysis of HER2 mutations and strategies to target them.

  10. A missense mutation of HOXA13 underlies hand-foot-genital syndrome in a Chinese family

    Indian Academy of Sciences (India)

    LIHUA CAO; CHEN CHEN; YUNJI LENG; LULU YAN; SHUSEN WANG; XUE ZHANG; YANG LUO

    2017-09-01

    Hand-foot-genital syndrome (HFGS) is a rare autosomal dominant inherited syndrome characterized by limb malformations and urogenital defects. HFGS is caused by mutations in the HOXA13 gene. The aim of this study was to identifycausative mutations in individuals and to explore the molecular pathogenesis in a Chinese family with HFGS. We performed Sanger sequencing and identified a recurrent missense mutation in the homeodomain (c.1123G>T, p.V375F) of HOXA13, molecular modelling predicted the mutation would affect DNA binding, and a luciferase reporter assay indicated that it impaired the ability ofHOXA13 to activate transcription of the human EPHA7 promoter. This is the first report of the molecular basis for HFGS caused by missense mutations of HOXA13.

  11. Molecular evaluation of a novel missense mutation & an insertional truncating mutation in SUMF1 gene

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    Udhaya H Kotecha

    2014-01-01

    Full Text Available Background & objectives: Multiple suphphatase deficiency (MSD is an autosomal recessive disorder affecting the post translational activation of all enzymes of the sulphatase family. To date, approximately 30 different mutations have been identified in the causative gene, sulfatase modifying factor 1 (SUMF1. We describe here the mutation analysis of a case of MSD. Methods: The proband was a four year old boy with developmental delay followed by neuroregression. He had coarse facies, appendicular hypertonia, truncal ataxia and ichthyosis limited to both lower limbs. Radiographs showed dysostosis multiplex. Clinical suspicion of MSD was confirmed by enzyme analysis of four enzymes of the sulphatase group. Results: The patient was compound heterozygote for a c.451A>G (p.K151E substitution in exon 3 and a single base insertion mutation (c.690_691 InsT in exon 5 in the SUMF1 gene. The bioinformatic analysis of the missense mutation revealed no apparent effect on the overall structure. However, the mutated 151-amino acid residue was found to be adjacent to the substrate binding and the active site residues, thereby affecting the substrate binding and/or catalytic activity, resulting in almost complete loss of enzyme function. Conclusions: The two mutations identified in the present case were novel. This is perhaps the first report of an insertion mutation in SUMF1 causing premature truncation of the protein.

  12. Computational study of missense mutations in phenylalanine hydroxylase.

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    Réblová, Kamila; Kulhánek, Petr; Fajkusová, Lenka

    2015-04-01

    Hyperphenylalaninemia (HPA) is one of the most common metabolic disorders. HPA, which is transmitted by an autosomal recessive mode of inheritance, is caused by mutations of the phenylalanine hydroxylase gene. Most mutations are missense and lead to reduced protein stability and/or impaired catalytic function. The impact of such mutations varies, ranging from classical phenylketonuria (PKU), mild PKU, to non-PKU HPA phenotypes. Despite the fact that HPA is a monogenic disease, clinical data show that one PKU genotype can be associated with more in vivo phenotypes, which indicates the role of other (still unknown) factors. To better understand the phenotype-genotype relationships, we analyzed computationally the impact of missense mutations in homozygotes stored in the BIOPKU database. A total of 34 selected homozygous genotypes was divided into two main groups according to their phenotypes: (A) genotypes leading to non-PKU HPA or combined phenotype non-PKU HPA/mild PKU and (B) genotypes leading to classical PKU, mild PKU or combined phenotype mild PKU/classical PKU. Combining in silico analysis and molecular dynamics simulations (in total 3 μs) we described the structural impact of the mutations, which allowed us to separate 32 out of 34 mutations between groups A and B. Testing the simulation conditions revealed that the outcome of mutant simulations can be modulated by the ionic strength. We also employed programs SNPs3D, Polyphen-2, and SIFT but based on the predictions performed we were not able to discriminate mutations with mild and severe PKU phenotypes.

  13. Computational and molecular approaches for predicting unreported causal missense mutations in Belgian patients with haemophilia A.

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    Lannoy, N; Abinet, I; Bosmans, A; Lambert, C; Vermylen, C; Hermans, C

    2012-05-01

    Haemophilia A (HA) is caused by widespread mutations in the factor VIII gene. The high spontaneous mutation rate of this gene means that roughly 40% of HA mutations are private. This study aimed to describe the approaches used to confirm private disease-causing mutations in a cohort of Belgian HA patients. We studied 148 unrelated HA families for the presence of intron 22 and intron 1 inversion by Southern blotting and polymerase chain reaction (PCR). Multiplex ligation-dependent probe amplification (MLPA) assay was used to detect large genomic rearrangements. Detection of point mutations was performed by DNA sequencing. Predicting the causal impact of new non-synonymous changes was studied by two general strategies: (i) molecular approaches such as family cosegregation, evaluation of the implicated codon based on phylogenic separated species and absence of the mutation in the general Belgian population, and (ii) bioinformatics approaches to analyse the potential functional consequences of missense mutations. Among the 148 HA patients, in addition to common intron 22 and intron 1 inversions as well as large deletions or duplications, 67 different point mutations were identified, of which 42 had been reported in the HAMSTeRS database, and 25 were novel including 10 null variants for which RNA analyses confirmed the causal effect of mutations located in a splice site consensus and 15 missense mutations whose causality was demonstrated by molecular approaches and bioinformatics. This article reports several strategies to evaluate the deleterious consequences of unreported F8 substitutions in a large cohort of HA patients.

  14. Missense mutations of the fibrillin-1 gene in two Chinese patients with severe Marfan syndrome

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To describe two Chinese patients with severe forms of Marfan syndrome and to report findings of mutational analysis of the fibrillin-1 (FBN1) gene.Methods Two Chinese patients were studied, one suffering from Marfan syndrome of infantile onset and the other of neonatal onset. Their clinical features were described. Mutational analysis of the FBN1 gene was performed using polymerase chain reaction (PCR) technique and direct sequencing of exons 23 - 32,where the mutational hotspots for severe forms of Marfan syndrome are located.Results Two missense mutations were successfully identified, a G3037A transition and an A3083T transversion, the latter being an unreported mutation.Conclusion Taking advantage of the clustering phenomenon of mutations in severe forms of Marfan syndrome, one can identify FBN1 mutations in these patients by first screening the mutational hotspots,thus reducing the effort that would otherwise be much greater because of the size of the gene.

  15. E-cadherin destabilization accounts for the pathogenicity of missense mutations in hereditary diffuse gastric cancer.

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    Joana Simões-Correia

    Full Text Available E-cadherin is critical for the maintenance of tissue architecture due to its role in cell-cell adhesion. E-cadherin mutations are the genetic cause of Hereditary Diffuse Gastric Cancer (HDGC and missense mutations represent a clinical burden, due to the uncertainty of their pathogenic role. In vitro and in vivo, most mutations lead to loss-of-function, although the causal factor is unknown for the majority. We hypothesized that destabilization could account for the pathogenicity of E-cadherin missense mutations in HDGC, and tested our hypothesis using in silico and in vitro tools. FoldX algorithm was used to calculate the impact of each mutation in E-cadherin native-state stability, and the analysis was complemented with evolutionary conservation, by SIFT. Interestingly, HDGC patients harbouring germline E-cadherin destabilizing mutants present a younger age at diagnosis or death, suggesting that the loss of native-state stability of E-cadherin accounts for the disease phenotype. To elucidate the biological relevance of E-cadherin destabilization in HDGC, we investigated a group of newly identified HDGC-associated mutations (E185V, S232C and L583R, of which L583R is predicted to be destabilizing. We show that this mutation is not functional in vitro, exhibits shorter half-life and is unable to mature, due to premature proteasome-dependent degradation, a phenotype reverted by stabilization with the artificial mutation L583I (structurally tolerated. Herein we report E-cadherin structural models suitable to predict the impact of the majority of cancer-associated missense mutations and we show that E-cadherin destabilization leads to loss-of-function in vitro and increased pathogenicity in vivo.

  16. A Novel AXIN2 Missense Mutation Is Associated with Non-Syndromic Oligodontia.

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    Haochen Liu

    Full Text Available Oligodontia is defined as the congenital absence of six or more permanent teeth, excluding the third molars. Oligodontia may contribute to masticatory dysfunction, speech alteration, aesthetic problems and malocclusion. Numerous gene mutations have been association with oligodontia. In the present study, we identified a de novo AXIN2 missense mutation (c.314T>G in a Chinese individual with non-syndromic oligodontia. This mutation results in the substitution of Val at residue 105 for Gly (p.Val105Gly; residue 105 is located in the highly conserved regulator of G protein signaling (RGS domain of the AXIN2 protein. This is the first report indicating that a mutation in the RGS domain of AXIN2 is responsible for non-syndromic oligodontia. Our study supports the relationship between AXIN2 mutation and non-syndromic oligodontia and extends the mutation spectrum of the AXIN2 gene.

  17. Identification of a novel missense mutation of MAF in a Japanese family with congenital cataract by whole exome sequencing: a clinical report and review of literature.

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    Narumi, Yoko; Nishina, Sachiko; Tokimitsu, Motoharu; Aoki, Yoko; Kosaki, Rika; Wakui, Keiko; Azuma, Noriyuki; Murata, Toshinori; Takada, Fumio; Fukushima, Yoshimitsu; Kosho, Tomoki

    2014-05-01

    Congenital cataracts are the most important cause of severe visual impairment in infants. Genetic factors contribute to the disease development and 29 genes are known to cause congenital cataracts. Identifying the genetic cause of congenital cataracts can be difficult because of genetic heterogeneity. V-maf avian musculoaponeurotic fibrosarcoma oncogene homolog (MAF) encodes a basic region/leucine zipper transcription factor that plays a key role as a regulator of embryonic lens fiber cell development. MAF mutations have been reported to cause juvenile-onset pulverulent cataract, microcornea, iris coloboma, and other anterior segment dysgenesis. We report on six patients in a family who have congenital cataracts were identified MAF mutation by whole exome sequencing (WES). The heterozygous MAF mutation Q303L detected in the present family occurs in a well conserved glutamine residue at the basic region of the DNA-binding domain. All affected members showed congenital cataracts. Three of the six members showed microcornea and one showed iris coloboma. Congenital cataracts with MAF mutation exhibited phenotypically variable cataracts within the family. Review of the patients with MAF mutations supports the notion that congenital cataracts caused by MAF mutations could be accompanied by microcornea and/or iris coloboma. WES is a useful tool for detecting disease-causing mutations in patients with genetically heterogeneous conditions.

  18. Papillorenal syndrome-causing missense mutations in PAX2/Pax2 result in hypomorphic alleles in mouse and human.

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    Ramakrishna P Alur

    2010-03-01

    Full Text Available Papillorenal syndrome (PRS, also known as renal-coloboma syndrome is an autosomal dominant disease characterized by potentially-blinding congenital optic nerve excavation and congenital kidney abnormalities. Many patients with PRS have mutations in the paired box transcription factor gene, PAX2. Although most mutations in PAX2 are predicted to result in complete loss of one allele's function, three missense mutations have been reported, raising the possibility that more subtle alterations in PAX2 function may be disease-causing. To date, the molecular behaviors of these mutations have not been explored. We describe a novel mouse model of PRS due to a missense mutation in a highly-conserved threonine residue in the paired domain of Pax2 (p.T74A that recapitulates the ocular and kidney findings of patients. This mutation is in the Pax2 paired domain at the same location as two human missense mutations. We show that all three missense mutations disrupt potentially critical hydrogen bonds in atomic models and result in reduced Pax2 transactivation, but do not affect nuclear localization, steady state mRNA levels, or the ability of Pax2 to bind its DNA consensus sequence. Moreover, these mutations show reduced steady-state levels of Pax2 protein in vitro and (for p.T74A in vivo, likely by reducing protein stability. These results suggest that hypomorphic alleles of PAX2/Pax2 can lead to significant disease in humans and mice.

  19. A novel missense mutation of the DDHD1 gene associated with juvenile amyotrophic lateral sclerosis

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    Chujun Wu

    2016-12-01

    Full Text Available Background: Juvenile amyotrophic lateral sclerosis (jALS is a rare form of ALS with an onset age of less than 25 years and is frequently thought to be genetic in origin. DDHD1 gene mutations have been reported to be associated with the SPG28 subtype of autosomal recessive HSP but have never been reported in jALS patients.Methods: Gene screens for the causative genes of ALS, HSP and CMT using next-generation sequencing (NGS technologies were performed on a jALS patient. Sanger sequencing was used to validate identified variants and perform segregation analysis.Results: We identified a novel c.1483A>G (p.Met495Val homozygous missense mutation of the DDHD1 gene in the jALS patient. All of his parents and young bother were heterozygous for this mutation. The mutation was not found in 800 Chinese control subjects or the data of dbSNP, ExAC and 1000G.Conclusion: The novel c.1483A>G (p.Met495Val missense mutation of the DDHD1 gene could be a causative mutation of autosomal recessive jALS.

  20. Comprehensive functional annotation of 18 missense mutations found in suspected hemochromatosis type 4 patients.

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    Callebaut, Isabelle; Joubrel, Rozenn; Pissard, Serge; Kannengiesser, Caroline; Gérolami, Victoria; Ged, Cécile; Cadet, Estelle; Cartault, François; Ka, Chandran; Gourlaouen, Isabelle; Gourhant, Lénaick; Oudin, Claire; Goossens, Michel; Grandchamp, Bernard; De Verneuil, Hubert; Rochette, Jacques; Férec, Claude; Le Gac, Gérald

    2014-09-01

    Hemochromatosis type 4 is a rare form of primary iron overload transmitted as an autosomal dominant trait caused by mutations in the gene encoding the iron transport protein ferroportin 1 (SLC40A1). SLC40A1 mutations fall into two functional categories (loss- versus gain-of-function) underlying two distinct clinical entities (hemochromatosis type 4A versus type 4B). However, the vast majority of SLC40A1 mutations are rare missense variations, with only a few showing strong evidence of causality. The present study reports the results of an integrated approach collecting genetic and phenotypic data from 44 suspected hemochromatosis type 4 patients, with comprehensive structural and functional annotations. Causality was demonstrated for 10 missense variants, showing a clear dichotomy between the two hemochromatosis type 4 subtypes. Two subgroups of loss-of-function mutations were distinguished: one impairing cell-surface expression and one altering only iron egress. Additionally, a new gain-of-function mutation was identified, and the degradation of ferroportin on hepcidin binding was shown to probably depend on the integrity of a large extracellular loop outside of the hepcidin-binding domain. Eight further missense variations, on the other hand, were shown to have no discernible effects at either protein or RNA level; these were found in apparently isolated patients and were associated with a less severe phenotype. The present findings illustrate the importance of combining in silico and biochemical approaches to fully distinguish pathogenic SLC40A1 mutations from benign variants. This has profound implications for patient management.

  1. Avoiding dangerous missense: thermophiles display especially low mutation rates.

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    John W Drake

    2009-06-01

    Full Text Available Rates of spontaneous mutation have been estimated under optimal growth conditions for a variety of DNA-based microbes, including viruses, bacteria, and eukaryotes. When expressed as genomic mutation rates, most of the values were in the vicinity of 0.003-0.004 with a range of less than two-fold. Because the genome sizes varied by roughly 10(4-fold, the mutation rates per average base pair varied inversely by a similar factor. Even though the commonality of the observed genomic rates remains unexplained, it implies that mutation rates in unstressed microbes reach values that can be finely tuned by evolution. An insight originating in the 1920s and maturing in the 1960s proposed that the genomic mutation rate would reflect a balance between the deleterious effect of the average mutation and the cost of further reducing the mutation rate. If this view is correct, then increasing the deleterious impact of the average mutation should be countered by reducing the genomic mutation rate. It is a common observation that many neutral or nearly neutral mutations become strongly deleterious at higher temperatures, in which case they are called temperature-sensitive mutations. Recently, the kinds and rates of spontaneous mutations were described for two microbial thermophiles, a bacterium and an archaeon. Using an updated method to extrapolate from mutation-reporter genes to whole genomes reveals that the rate of base substitutions is substantially lower in these two thermophiles than in mesophiles. This result provides the first experimental support for the concept of an evolved balance between the total genomic impact of mutations and the cost of further reducing the basal mutation rate.

  2. Novel LINS1 missense mutation in a family with non-syndromic intellectual disability.

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    Sheth, Jayesh; Ranjan, Gyan; Shah, Krati; Bhavsar, Riddhi; Sheth, Frenny

    2017-04-01

    Newer sequencing technologies decipher molecular variations and increase the knowledge of pathogenesis of complex diseases like intellectual disability (ID), affecting 2-3% of the population. We report a novel family with a missense mutation in LINS1 as a cause for non-syndromic ID. Clinical exome sequencing for ID related genes carried out for a male with dysmorphism, mutism, and cognitive delay was uninformative. Subsequently, "pathogenic" and "likely pathogenic" variants associated with other inherited disorders were searched for as secondary findings. Further, PCR-RFLP carried out in other family members confirmed the result. A novel missense variant (c.937G>A) in exon 5 of LINS1 was detected in the proband. His affected elder brother was homozygous and the parents were heterozygous respectively, for the mutation. No mutation was observed in his unaffected sister. Mutations in LINS1 were suspected in this non-syndromic ID case with mutism. LINS1 alterations affect ELAV1 expression and result in reduction in the commissural axonal growth, thus affecting peripheral and central neuronal function. LINS1 acts in association with β-catenin to influence WNT1 signaling. It is hypothesized that mutations in LINS1 may alter HuR expression during neural differentiation, leading to ID in humans. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. MECP2 missense mutations outside the canonical MBD and TRD domains in males with intellectual disability

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    Failla, Pinella; Di Marco, Chiara; Grozeva, Detelina; Mencarelli, Maria Antonietta; Spiga, Ottavia; Mari, Francesca; Meloni, Ilaria; Raymond, Lucy; Renieri, Alessandra; Romano, Corrado; Ariani, Francesca

    2015-01-01

    Methyl-CpG binding protein 2 (MeCP2) is a nuclear protein highly expressed in neurons that is involved in transcriptional modulation and chromatin remodeling. Mutations in MECP2 in females are associated with Rett syndrome, a neurological disorder characterized by a normal neonatal period, followed by the arrest of development and regression of acquired skills. Although it was initially thought that MECP2 pathogenic mutations in males were not compatible with life, starting from 1999 about 60 male patients have been identified and their phenotype varies from severe neonatal encephalopathy to mild intellectual disability. Targeted Next Generation Sequencing of a panel of intellectual disability related genes was performed on two unrelated male patients, and two missense variants in MECP2 were identified (p.Gly185Val and p.Arg167Trp). These variants lie outside the canonical MBD and TRD domains, where the pathogenicity of missense variants is more difficult to establish. In both families, variants were found in all affected siblings and were inherited from the asymptomatic mother, showing skewed X-chromosome inactivation. We report here the first missense variant located in AT-hook domain 1 and we underline the importance of MECP2 substitutions outside the canonical MeCP2 domains in X-linked intellectual disability. PMID:26490184

  4. Missense mutations in the growth hormone receptor dimerization region in Laron syndrome

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    Berg, M.A.; Francke, U. [Howard Hughes Medical Institute, Stanford, CA (United States)]|[Univ. of Stanford, CA (United States); Geffner, M.E.; Bersch, N. [Univ. of California, Los Angeles, CA (United States)] [and others

    1994-09-01

    Laron syndrome (LS) is an autosomal recessively inherited condition characterized by insensitivity to endogenous and exogenous GH. Affected individuals have severe episodes and other characteristic features. GH receptor gene mutations are present in all affected individuals in whom molecular studies have been reported. The GH receptor is a plasma membrane-spanning protein in which the extracellular domain binds circulating GH and the intracellular domain interacts with the JAK-2 kinase and possibly other intracellular signaling molecules. GH receptor dimerization occurs on GH binding and is thought to be required for normal signal transduction. We have studied the GH receptor genes of four unrelated individuals affected with LS from the United States, Italy, Saudi Arabia, and India. We have identified four different missense mutations that alter consecutive amino acids 152 to 155 in or near the dimerization domain of the GH receptor. One of these mutations, D152H, has been reported previously in Asian LS patients and, in in vitro studies, the mutant receptor was unable to dimerize. This report increases to over 20 the number of different GH receptor gene mutations that have been reported in LS patients and defines the first apparent mutational {open_quotes}hotspot{close_quotes} region in this gene. This cluster of mutations in patients with classic LS phenotype provides additional in vivo evidence that receptor dimerization plays an important role in signaling GH`s growth promoting and metabolic effects. Further in vitro studies of the mutations in this region are in progress.

  5. Genotype-Phenotype Correlations Emerging from the Identification of Missense Mutations in MBTPS2

    NARCIS (Netherlands)

    Bornholdt, D.; Atkinson, T.P.; Bouadjar, B.; Catteau, B.; Cox, H.; Silva, D. De; Fischer, J.; Gunasekera, C.N.; Hadj-Rabia, S.; Happle, R.; Holder-Espinasse, M.; Kaminski, E.; Konig, A.; Megarbane, A.; Megarbane, H.; Neidel, U.; Oeffner, F.; Oji, V.; Theos, A.; Traupe, H.; Vahlquist, A.; Bon, B.W. van; Virtanen, M.; Grzeschik, K.H.

    2013-01-01

    Missense mutations affecting membrane-bound transcription factor protease site 2 (MBTPS2) have been associated with Ichthyosis Follicularis with Atrichia and Photophobia (IFAP) syndrome with or without BRESHECK syndrome, with keratosis follicularis spinulosa decalvans, and Olmsted syndrome. This

  6. Genotype-Phenotype Correlations Emerging from the Identification of Missense Mutations in MBTPS2

    NARCIS (Netherlands)

    Bornholdt, D.; Atkinson, T.P.; Bouadjar, B.; Catteau, B.; Cox, H.; Silva, D. De; Fischer, J.; Gunasekera, C.N.; Hadj-Rabia, S.; Happle, R.; Holder-Espinasse, M.; Kaminski, E.; Konig, A.; Megarbane, A.; Megarbane, H.; Neidel, U.; Oeffner, F.; Oji, V.; Theos, A.; Traupe, H.; Vahlquist, A.; Bon, B.W. van; Virtanen, M.; Grzeschik, K.H.

    2013-01-01

    Missense mutations affecting membrane-bound transcription factor protease site 2 (MBTPS2) have been associated with Ichthyosis Follicularis with Atrichia and Photophobia (IFAP) syndrome with or without BRESHECK syndrome, with keratosis follicularis spinulosa decalvans, and Olmsted syndrome. This met

  7. Brittle Cornea Syndrome Associated with a Missense Mutation in the Zinc-Finger 469 Gene

    DEFF Research Database (Denmark)

    Christensen, Anne Elisabeth; Knappskog, Per Morten; Midtbø, Marit

    2010-01-01

    Purpose: To investigate the diverse clinical manifestations, identify the causative mutation and explain the association with red hair in a family with brittle cornea syndrome (BCS). Methods: Eight family members in three generations underwent ophthalmic, dental, and general medical examination......, dental anomalies, hearing loss and minor cardiac defects. The morphologies of the skin biopsies were normal except that in some areas slightly thinner collagen fibrils were seen in one of the affected individuals. Molecular genetic analysis revealed a novel missense mutation of ZNF469, c.10016G....... Reduced BMD and atypical dental crown morphology have not been reported previously. We confirm that BCS is associated with mutations in ZNF469. The association with red hair in some individuals with BCS is likely to occur by chance....

  8. Functional characterization of rare missense mutations in MLH1 and MSH2 identified in Danish colorectal cancer patients

    DEFF Research Database (Denmark)

    Christensen, Lise Lotte; Kariola, Reetta; Korhonen, Mari K

    2009-01-01

    Recently, we have performed a population based study to analyse the frequency of colorectal cancer related MLH1 and MSH2 missense mutations in the Danish population. Half of the analyzed mutations were rare and most likely only present in the families where they were identified originally. Some...... of the missense mutations were located in conserved regions in the MLH1 and MSH2 proteins indicating a relation to disease development. In the present study, we functionally characterized 10 rare missense mutations in MLH1 and MSH2 identified in 13 Danish CRC families. To elucidate the pathogenicity...... of the missense mutations, we carried out in vitro functional analyses. The missense mutations were analyzed for their effect on protein expression and repair efficiency. The results of the functional analysis were correlated with clinical data on the families carrying these mutations. Eight missense mutations...

  9. Population-based estimate of prostate cancer risk for carriers of the HOXB13 missense mutation G84E.

    Directory of Open Access Journals (Sweden)

    Robert J MacInnis

    Full Text Available The HOXB13 missense mutation G84E (rs138213197 is associated with increased risk of prostate cancer, but the current estimate of increased risk has a wide confidence interval (width of 95% confidence interval (CI >200-fold so the point estimate of 20-fold increased risk could be misleading. Population-based family studies can be more informative for estimating risks for rare variants, therefore, we screened for mutations in an Australian population-based series of early-onset prostate cancer cases (probands. We found that 19 of 1,384 (1.4% probands carried the missense mutation, and of these, six (32% had a family history of prostate cancer. We tested the 22 relatives of carriers diagnosed from 1998 to 2008 for whom we had a DNA sample, and found seven more carriers and one obligate carrier. The age-specific incidence for carriers was estimated to be, on average, 16.4 (95% CI 2.5-107.2 times that for the population over the time frame when the relatives were at risk prior to baseline. We then estimated the age and birth year- specific cumulative risk of prostate cancer (penetrance for carriers. For example, the penetrance for an unaffected male carrier born in 1950 was 19% (95% CI 5-46% at age 60 years, 44% (95% CI 18-74% at age 70 years and 60% (95% CI 30-85% at age 80 years. Our study has provided a population-based estimate of the average risk of prostate cancer for HOXB13 missense mutation G84E carriers that can be used to guide clinical practice and research. This study has also shown that the majority of hereditary prostate cancers due to the HOXB13 missense mutation are 'sporadic' in the sense that unselected cases with the missense mutation do not typically report having a family history of prostate cancer.

  10. Type B mandibuloacral dysplasia with congenital myopathy due to homozygous ZMPSTE24 missense mutation.

    Science.gov (United States)

    Ben Yaou, Rabah; Navarro, Claire; Quijano-Roy, Susana; Bertrand, Anne T; Massart, Catherine; De Sandre-Giovannoli, Annachiara; Cadiñanos, Juan; Mamchaoui, Kamel; Butler-Browne, Gillian; Estournet, Brigitte; Richard, Pascale; Barois, Annie; Lévy, Nicolas; Bonne, Gisèle

    2011-06-01

    Mutation in ZMPSTE24 gene, encoding a major metalloprotease, leads to defective prelamin A processing and causes type B mandibuloacral dysplasia, as well as the lethal neonatal restrictive dermopathy syndrome. Phenotype severity is correlated with the residual enzyme activity of ZMPSTE24 and accumulation of prelamin A. We had previously demonstrated that a complete loss of function in ZMPSTE24 was lethal in the neonatal period, whereas compound heterozygous mutations including one PTC and one missense mutation were associated with type B mandibuloacral dysplasia. In this study, we report a 30-year longitudinal clinical survey of a patient harboring a novel severe and complex phenotype, combining an early-onset progeroid syndrome and a congenital myopathy with fiber-type disproportion. A unique homozygous missense ZMPSTE24 mutation (c.281T>C, p.Leu94Pro) was identified and predicted to produce two possible ZMPSTE24 conformations, leading to a partial loss of function. Western blot analysis revealed a major reduction of ZMPSTE24, together with the presence of unprocessed prelamin A and decreased levels of lamin A, in the patient's primary skin fibroblasts. These cells exhibited significant reductions in lifespan associated with major abnormalities of the nuclear shape and structure. This is the first report of MAD presenting with confirmed myopathic abnormalities associated with ZMPSTE24 defects, extending the clinical spectrum of ZMPSTE24 gene mutations. Moreover, our results suggest that defective prelamin A processing affects muscle regeneration and development, thus providing new insights into the disease mechanism of prelamin A-defective associated syndromes in general.

  11. Functional characterization of a CRH missense mutation identified in an ADNFLE family.

    Directory of Open Access Journals (Sweden)

    Veronica Sansoni

    Full Text Available Nocturnal frontal lobe epilepsy has been historically considered a channelopathy caused by mutations in subunits of the neuronal nicotinic acetylcholine receptor or in a recently reported potassium channel. However, these mutations account for only a minority of patients, and the existence of at least a new locus for the disease has been demonstrated. In 2005, we detected two nucleotide variations in the promoter of the CRH gene coding for the corticotropin releasing hormone in 7 patients. These variations cosegregated with the disease and were demonstrated to alter the cellular levels of this hormone. Here, we report the identification in an Italian affected family of a novel missense mutation (hpreproCRH p.Pro30Arg located in the region of the CRH coding for the protein pro-sequence. The mutation was detected in heterozygosity in the two affected individuals. In vitro assays demonstrated that this mutation results in reduced levels of protein secretion in the short time thus suggesting that mutated people could present an altered capability to respond immediately to stress agents.

  12. Novel mutations, including a novel G659A missense mutation, of the FUT1 gene are responsible for the para-Bombay phenotype.

    Science.gov (United States)

    Sun, C F; Lo, M D; Lee, C H; Chu, D C

    2000-10-01

    Para-Bombay phenotype, with an estimated incidence of 1 in 8000 in Taiwanese residents based on serological analysis, is caused by aberrant alpha(1,2)-fucosyltransferase function and hence diminished H-antigen synthesis. In an individual with para-Bombay phenotype, DNA sequencing revealed two missense mutations previously reported C658T mutation and a novel G659A mutation. Haplotype analysis with restriction enzyme digestion showed that the two mutations are located on opposing alleles of the H (FUT1) gene and lead to compound heterozygosity. Since no other known genetic changes were evident, it appears that the new missense mutation, G659A, is deleterious to the alpha(1,2)-fucosyltransferase function encoded by the H (FUT1) gene.

  13. Hypomyelinating leukodystrophy-associated missense mutation in HSPD1 blunts mitochondrial dynamics.

    Science.gov (United States)

    Miyamoto, Yuki; Eguchi, Takahiro; Kawahara, Kazuko; Hasegawa, Nanami; Nakamura, Kazuaki; Funakoshi-Tago, Megumi; Tanoue, Akito; Tamura, Hiroomi; Yamauchi, Junji

    2015-07-03

    Myelin-forming glial cells undergo dynamic morphological changes in order to produce mature myelin sheaths with multiple layers. In the central nervous system (CNS), oligodendrocytes differentiate to insulate neuronal axons with myelin sheaths. Myelin sheaths play a key role in homeostasis of the nervous system, but their related disorders lead not only to dismyelination and repeated demyelination but also to severe neuropathies. Hereditary hypomyelinating leukodystrophies (HLDs) are a group of such diseases affecting oligodendrocytes and are often caused by missense mutations of the respective responsible genes. Despite increasing identification of gene mutations through advanced nucleotide sequencing technology, studies on the relationships between gene mutations and their effects on cellular and subcellular aberrance have not followed at the same rapid pace. In this study, we report that an HLD4-associated (Asp-29-to-Gly) mutant of mitochondrial heat shock 60-kDa protein 1 (HSPD1) causes short-length morphologies and increases the numbers of mitochondria due to their aberrant fission and fusion cycles. In experiments using a fluorescent dye probe, this mutation decreases the mitochondrial membrane potential. Also, mitochondria accumulate in perinuclear regions. HLD4-associated HSPD1 mutant blunts mitochondrial dynamics, probably resulting in oligodendrocyte malfunction. This study constitutes a first finding concerning the relationship between disease-associated HSPD1 mutation and mitochondrial dynamics, which may be similar to the relationship between another disease-associated HSPD1 mutation (MitCHAP-60 disease) and aberrant mitochondrial dynamics.

  14. A frequent splicing mutation and novel missense mutations color the updated mutational spectrum of classic galactosemia in Portugal.

    Science.gov (United States)

    Coelho, Ana I; Ramos, Ruben; Gaspar, Ana; Costa, Cláudia; Oliveira, Anabela; Diogo, Luísa; Garcia, Paula; Paiva, Sandra; Martins, Esmeralda; Teles, Elisa Leão; Rodrigues, Esmeralda; Cardoso, M Teresa; Ferreira, Elena; Sequeira, Sílvia; Leite, Margarida; Silva, Maria João; de Almeida, Isabel Tavares; Vicente, João B; Rivera, Isabel

    2014-01-01

    Classic galactosemia is an autosomal recessive disorder caused by deficient galactose-1-phosphate uridylyltransferase (GALT) activity. Patients develop symptoms in the neonatal period, which can be ameliorated by dietary restriction of galactose. Many patients develop long-term complications, with a broad range of clinical symptoms whose pathophysiology is poorly understood. The high allelic heterogeneity of GALT gene that characterizes this disorder is thought to play a determinant role in biochemical and clinical phenotypes. We aimed to characterize the mutational spectrum of GALT deficiency in Portugal and to assess potential genotype-phenotype correlations. Direct sequencing of the GALT gene and in silico analyses were employed to evaluate the impact of uncharacterized mutations upon GALT functionality. Molecular characterization of 42 galactosemic Portuguese patients revealed a mutational spectrum comprising 14 nucleotide substitutions: ten missense, two nonsense and two putative splicing mutations. Sixteen different genotypic combinations were detected, half of the patients being p.Q188R homozygotes. Notably, the second most frequent variation is a splicing mutation. In silico predictions complemented by a close-up on the mutations in the protein structure suggest that uncharacterized missense mutations have cumulative point effects on protein stability, oligomeric state, or substrate binding. One splicing mutation is predicted to cause an alternative splicing event. This study reinforces the difficulty in establishing a genotype-phenotype correlation in classic galactosemia, a monogenic disease whose complex pathogenesis and clinical features emphasize the need to expand the knowledge on this "cloudy" disorder.

  15. Missense mutations in FBN1 exons 41 and 42 cause Weill-Marchesani syndrome with thoracic aortic disease and Marfan syndrome.

    Science.gov (United States)

    Cecchi, Alana; Ogawa, Naomi; Martinez, Hugo R; Carlson, Alicia; Fan, Yuxin; Penny, Daniel J; Guo, Dong-chuan; Eisenberg, Steven; Safi, Hazim; Estrera, Anthony; Lewis, Richard A; Meyers, Deborah; Milewicz, Dianna M

    2013-09-01

    Mutations in FBN1 cause a range of overlapping but distinct conditions including Marfan syndrome (MFS), Weill-Marchesani syndrome (WMS), familial thoracic aortic aneurysms/dissections (FTAAD), acromicric dysplasia (AD), and geleophysic dysplasia (GD). Two forms of acromelic dysplasia, AD and GD, characterized by short stature, brachydactyly, reduced joint mobility, and characteristic facies, result from heterozygous missense mutations occurring in exons 41 and 42 of FBN1; missense mutations in these exons have not been reported to cause MFS or other syndromes. Here we report on probands with MFS and WMS who have heterozygous FBN1 missense mutations in exons 41 and 42, respectively. The proband with WMS has ectopia lentis, short stature, thickened pinnae, tight skin, striae atrophicae, reduced extension of the elbows, contractures of the fingers and toes, and brachydactyly and has a missense mutation in exon 42 of FBN1 (c.5242T>C; p.C1748R). He also experienced a previously unreported complication of WMS, an acute thoracic aortic dissection. The second proband displays classic characteristics of MFS, including ectopia lentis, skeletal features, and aortic root dilatation, and has a missense mutation in exon 41 of FBN1 (c.5084G>A; p.C1695Y). These phenotypes provide evidence that missense mutations in exons 41 and 42 of FBN1 lead to MFS and WMS in addition to AD and GD and also suggest that all individuals with pathogenic FBN1 mutations in these exons should be assessed for thoracic aortic disease and ectopia lentis. Further studies are necessary to elucidate the factors responsible for the different phenotypes associated with missense mutations in these exons of FBN1.

  16. Cole-Carpenter syndrome is caused by a heterozygous missense mutation in P4HB.

    Science.gov (United States)

    Rauch, Frank; Fahiminiya, Somayyeh; Majewski, Jacek; Carrot-Zhang, Jian; Boudko, Sergei; Glorieux, Francis; Mort, John S; Bächinger, Hans-Peter; Moffatt, Pierre

    2015-03-05

    Cole-Carpenter syndrome is a severe bone fragility disorder that is characterized by frequent fractures, craniosynostosis, ocular proptosis, hydrocephalus, and distinctive facial features. To identify the cause of Cole-Carpenter syndrome in the two individuals whose clinical results were presented in the original description of this disorder, we performed whole-exome sequencing of genomic DNA samples from both individuals. The two unrelated individuals had the same heterozygous missense mutation in exon 9 of P4HB (NM_000918.3: c.1178A>G [p.Tyr393Cys]), the gene that encodes protein disulfide isomerase (PDI). In one individual, the P4HB mutation had arisen de novo, whereas in the other the mutation was transmitted from the clinically unaffected father who was a mosaic carrier of the variant. The mutation was located in the C-terminal disulfide isomerase domain of PDI, sterically close to the enzymatic center, and affected disulfide isomerase activity in vitro. Skin fibroblasts showed signs of increased endoplasmic reticulum stress, but despite the reported importance of PDI for collagen type I production, the rate of collagen type I secretion appeared normal. In conclusion, Cole-Carpenter syndrome is caused by a specific de novo mutation in P4HB that impairs the disulfide isomerase activity of PDI.

  17. Analyses of MMP20 Missense Mutations in Two Families with Hypomaturation Amelogenesis Imperfecta

    Directory of Open Access Journals (Sweden)

    Jung-Wook Kim

    2017-04-01

    Full Text Available Amelogenesis imperfecta is a group of rare inherited disorders that affect tooth enamel formation, quantitatively and/or qualitatively. The aim of this study was to identify the genetic etiologies of two families presenting with hypomaturation amelogenesis imperfecta. DNA was isolated from peripheral blood samples obtained from participating family members. Whole exome sequencing was performed using DNA samples from the two probands. Sequencing data was aligned to the NCBI human reference genome (NCBI build 37.2, hg19 and sequence variations were annotated with the dbSNP build 138. Mutations in MMP20 were identified in both probands. A homozygous missense mutation (c.678T>A; p.His226Gln was identified in the consanguineous Family 1. Compound heterozygous MMP20 mutations (c.540T>A, p.Tyr180* and c.389C>T, p.Thr130Ile were identified in the non-consanguineous Family 2. Affected persons in Family 1 showed hypomaturation AI with dark brown discoloration, which is similar to the clinical phenotype in a previous report with the same mutation. However, the dentition of the Family 2 proband exhibited slight yellowish discoloration with reduced transparency. Functional analysis showed that the p.Thr130Ile mutant protein had reduced activity of MMP20, while there was no functional MMP20 in the Family 1 proband. These results expand the mutational spectrum of the MMP20 and broaden our understanding of genotype-phenotype correlations in amelogenesis imperfecta.

  18. Familial Mediterranean fever, Inflammation and Nephrotic Syndrome: Fibrillary Glomerulopathy and the M680I Missense Mutation

    Directory of Open Access Journals (Sweden)

    Semerdjian Ronald J

    2003-08-01

    Full Text Available Abstract Background Familial Mediterranean fever (FMF is an autosomal recessive disease characterized by inflammatory serositis (fever, peritonitis, synovitis and pleuritis. The gene locus responsible for FMF was identified in 1992 and localized to the short arm of chromosome 16. In 1997, a specific FMF gene locus, MEFV, was discovered to encode for a protein, pyrin that mediates inflammation. To date, more than forty missense mutations are known to exist. The diversity of mutations identified has provided insight into the variability of clinical presentation and disease progression. Case Report We report an individual heterozygous for the M680I gene mutation with a clinical diagnosis of FMF using the Tel-Hashomer criteria. Subsequently, the patient developed nephrotic syndrome with biopsy-confirmed fibrillary glomerulonephritis (FGN. Further diagnostic studies were unremarkable with clinical workup negative for amyloidosis or other secondary causes of nephrotic syndrome. Discussion Individuals with FMF are at greater risk for developing nephrotic syndrome. The most serious etiology is amyloidosis (AA variant with renal involvement, ultimately progressing to end-stage renal disease. Other known renal diseases in the FMF population include IgA nephropathy, IgM nephropathy, Henoch-Schönlein purpura as well as polyarteritis nodosa. Conclusion To our knowledge, this is the first association between FMF and the M680I mutation later complicated by nephrotic syndrome and fibrillary glomerulonephritis.

  19. GPIHBP1 Missense Mutations Often Cause Multimerization of GPIHBP1 and Thereby Prevent Lipoprotein Lipase Binding

    DEFF Research Database (Denmark)

    Beigneux, Anne P; Fong, Loren G; Bensadoun, Andre

    2015-01-01

    Rationale: GPIHBP1, a GPI-anchored protein of capillary endothelial cells, binds lipoprotein lipase (LPL) in the subendothelial spaces and shuttles it to the capillary lumen. GPIHBP1 missense mutations that interfere with LPL binding cause familial chylomicronemia. Objective: We sought to underst......Rationale: GPIHBP1, a GPI-anchored protein of capillary endothelial cells, binds lipoprotein lipase (LPL) in the subendothelial spaces and shuttles it to the capillary lumen. GPIHBP1 missense mutations that interfere with LPL binding cause familial chylomicronemia. Objective: We sought...

  20. Achromatopsia caused by novel missense mutations in the CNGA3 gene

    Directory of Open Access Journals (Sweden)

    Xi-Teng Chen

    2015-10-01

    Full Text Available AIM:To identify the genetic defects in a Chinese family with achromatopsia.METHODS:A 2.5-year-old boy, who displayed nystagmus, photophobia, and hyperopia since early infancy, was clinically evaluated. To further confirm and localize the causative mutations in this family, targeted region capture and next-generation sequencing of candidate genes, such as CNGA3, CNGB3, GNAT2, PDE6C, and PDE6H were performed using a custom-made capture array.RESULTS:Slit-lamp examination showed no specific findings in the anterior segments. The optic discs and maculae were normal on fundoscopy. The unaffected family members reported no ocular complaints. Clinical signs and symptoms were consistent with a clinical impression of autosomal recessive achromatopsia. The results of sequence analysis revealed two novel missense mutations in CNGA3, c.633T>A (p.D211E and c.1006G>T (p.V336F, with an autosomal recessive mode of inheritance.CONCLUSION: Genetic analysis of a Chinese family confirmed the clinical diagnosis of achromatopsia. Two novel mutations were identified in CNGA3, which extended the mutation spectrum of this disorder.

  1. WDR62 missense mutation in a consanguineous family with primary microcephaly.

    Science.gov (United States)

    Bacino, Carlos A; Arriola, Luis A; Wiszniewska, Joanna; Bonnen, Penelope E

    2012-03-01

    We report on a consanguineous couple with two affected sons who presented with primary microcephaly and moderate to severe intellectual disabilities. A SNP array uncovered two overlapping regions of copy-neutral absence of heterozygosity (AOH) in both sibs. This led to sequencing of WDR62, a gene that codes for a spindle pole protein recently identified as a cause of primary microcephaly. A homozygous missense mutation in WDR62, p.E400K, was found in both boys and segregated with the condition in this family. WDR62 is one of seven genes responsible for autosomal recessive primary microcephaly (MCPH), and appears to be one of the most frequently involved in MCPH following ASPM. Studies of ASPM and WDR62 should perhaps be pursued in all cases of primary microcephaly with or without gross brain malformations.

  2. Missense mutations in the TP53 DNA-binding domain predict outcomes in patients with advanced oral cavity squamous cell carcinoma.

    Science.gov (United States)

    Lapke, Nina; Lu, Yen-Jung; Liao, Chun-Ta; Lee, Li-Yu; Lin, Chien-Yu; Wang, Hung-Ming; Ng, Shu-Hang; Chen, Shu-Jen; Yen, Tzu-Chen

    2016-07-12

    TP53 mutations have been linked to reduced survival in patients with oral cavity squamous cell carcinoma (OSCC). However, the impact of different types of TP53 mutations remains unclear. Here, we demonstrate that the carriage of missense mutations in the TP53 DNA binding domain (DBD missense mutations) is associated with decreased disease-specific survival (DSS) compared with wild-type TP53 (P=0.002) in a cohort of 345 OSCC patients. In contrast, DSS of patients bearing all of the remaining TP53 mutations did not differ from that observed in wild-type TP53 patients (P=0.955). Our classification method for TP53 mutations was superior to previously reported approaches (disruptive, truncating, Evolutionary Action score, mutations in L2/L3/LSH) for distinguishing between low- and high-risk patients. When analyzed in combination with traditional clinicopathological factors, TP53 DBD missense mutations were an independent prognostic factor for shorter DSS (P=0.014) alongside with advanced AJCC T- and N-classifications and the presence of extracapsular spread. A scoring system that included the four independent prognostic factors allowed a reliable patient stratification into distinct risk groups (high-risk patients, 16.2%). Our results demonstrate the usefulness of TP53 DBD missense mutations combined with clinicopathological factors for improving the prognostic stratification of OSCC patients.

  3. Hypomyelinating leukodystrophy-associated missense mutation in HSPD1 blunts mitochondrial dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Yuki [Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535 (Japan); Eguchi, Takahiro [The Institute of Medical Science, The University of Tokyo, Minato, Tokyo 108-8639 (Japan); Kawahara, Kazuko [Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535 (Japan); Hasegawa, Nanami [Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535 (Japan); Faculty of Pharmacy, Keio University, Minato, Tokyo 105-8512 (Japan); Nakamura, Kazuaki [Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535 (Japan); Funakoshi-Tago, Megumi [Faculty of Pharmacy, Keio University, Minato, Tokyo 105-8512 (Japan); Tanoue, Akito [Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535 (Japan); Tamura, Hiroomi [Faculty of Pharmacy, Keio University, Minato, Tokyo 105-8512 (Japan); Yamauchi, Junji, E-mail: yamauchi-j@ncchd.go.jp [Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535 (Japan); Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo 113-8510 (Japan)

    2015-07-03

    Myelin-forming glial cells undergo dynamic morphological changes in order to produce mature myelin sheaths with multiple layers. In the central nervous system (CNS), oligodendrocytes differentiate to insulate neuronal axons with myelin sheaths. Myelin sheaths play a key role in homeostasis of the nervous system, but their related disorders lead not only to dismyelination and repeated demyelination but also to severe neuropathies. Hereditary hypomyelinating leukodystrophies (HLDs) are a group of such diseases affecting oligodendrocytes and are often caused by missense mutations of the respective responsible genes. Despite increasing identification of gene mutations through advanced nucleotide sequencing technology, studies on the relationships between gene mutations and their effects on cellular and subcellular aberrance have not followed at the same rapid pace. In this study, we report that an HLD4-associated (Asp-29-to-Gly) mutant of mitochondrial heat shock 60-kDa protein 1 (HSPD1) causes short-length morphologies and increases the numbers of mitochondria due to their aberrant fission and fusion cycles. In experiments using a fluorescent dye probe, this mutation decreases the mitochondrial membrane potential. Also, mitochondria accumulate in perinuclear regions. HLD4-associated HSPD1 mutant blunts mitochondrial dynamics, probably resulting in oligodendrocyte malfunction. This study constitutes a first finding concerning the relationship between disease-associated HSPD1 mutation and mitochondrial dynamics, which may be similar to the relationship between another disease-associated HSPD1 mutation (MitCHAP-60 disease) and aberrant mitochondrial dynamics. - Highlights: • The HLD4 mutant of HSPD1 decreases mitochondrial fission frequency. • The HLD4 mutant decreases mitochondrial fusion frequency. • Mitochondria harboring the HLD4 mutant exhibit slow motility. • The HLD4 mutant of HSPD1 decreases mitochondrial membrane potential. • HLD4-related diseases may

  4. The molecular basis of variable phenotypic severity among common missense mutations causing Rett syndrome.

    Science.gov (United States)

    Brown, Kyla; Selfridge, Jim; Lagger, Sabine; Connelly, John; De Sousa, Dina; Kerr, Alastair; Webb, Shaun; Guy, Jacky; Merusi, Cara; Koerner, Martha V; Bird, Adrian

    2016-02-01

    Rett syndrome is caused by mutations in the X-linked MECP2 gene, which encodes a chromosomal protein that binds to methylated DNA. Mouse models mirror the human disorder and therefore allow investigation of phenotypes at a molecular level. We describe an Mecp2 allelic series representing the three most common missense Rett syndrome (RTT) mutations, including first reports of Mecp2[R133C] and Mecp2[T158M] knock-in mice, in addition to Mecp2[R306C] mutant mice. Together these three alleles comprise ∼25% of all RTT mutations in humans, but they vary significantly in average severity. This spectrum is mimicked in the mouse models; R133C being least severe, T158M most severe and R306C of intermediate severity. Both R133C and T158M mutations cause compound phenotypes at the molecular level, combining compromised DNA binding with reduced stability, the destabilizing effect of T158M being more severe. Our findings contradict the hypothesis that the R133C mutation exclusively abolishes binding to hydroxymethylated DNA, as interactions with DNA containing methyl-CG, methyl-CA and hydroxymethyl-CA are all reduced in vivo. We find that MeCP2[T158M] is significantly less stable than MeCP2[R133C], which may account for the divergent clinical impact of the mutations. Overall, this allelic series recapitulates human RTT severity, reveals compound molecular aetiologies and provides a valuable resource in the search for personalized therapeutic interventions.

  5. Extra nuchal-type fibroma associated with elastosis, traumatic neuroma, a rare APC gene missense mutation, and a very rare MUTYH gene polymorphism: a case report and review of the literature*.

    Science.gov (United States)

    Linos, Konstantinos; Sedivcová, Monika; Cerna, Katerina; Sima, Radek; Kazakov, Dmitry V; Nazeer, Tipu; Glazyrin, Alexey; Valerian, Brian T; Carlson, J Andrew

    2011-11-01

    We report a case of an extra nuchal-type fibroma in a 51-year-old male suspected to have attenuated familial adenomatous polyposis (Gardner's syndrome), who presented with a longstanding buttock mass excised due to enlargement and pain. Histopathologically, lobules of haphazard, hypocellular, hyalinized collagen bundles replaced the dermis and subcutis and entrapped nerve bundles, mimicking Morton neuroma. Ramifying nerve twigs found around larger nerve fascicles showed the co-existence of traumatic neuroma. Elastic tissue stain revealed elastosis characterized by large, arborizing fibers lying between and within the hyalinized collagen bundles. Modified Masson's trichrome stain showed light blue staining of collagen bundles producing the hyalinized nodules with irregular, light red staining of collagen bundles at their periphery and within tumor collagen. Compression and/or degeneration of collagen and secondary elastosis with later entrapment by tumor collagen could explain this microscopic phenotype. By immunohistochemistry, tumor spindle cells expressed nuclear β-catenin and cyclin D1, mostly within regions of fibrosis implicating activation of the adenomatous polyposis coli (APC)-Wnt pathway. Genetic analysis showed a missense mutation in APC gene (c.7504G>A, p.G2502S in exon 15) and a functional homozygous polymorphism in the MUTYH gene (c.36+325G>C, (IVS1+5G/C)). Nuchal-type fibroma has been associated with Gardner's syndrome and trauma. In this patient, genetic predisposition coupled with repetitive, localized trauma and collagen degeneration may have provided the stimulus for the development of extra nuchal-type fibroma.

  6. In silico investigation of molecular effects caused by missense mutations in creatine transporter protein

    Science.gov (United States)

    Zhang, Zhe; Schwatz, Charles; Alexov, Emil

    2011-03-01

    Creatine transporter (CT) protein, which is encoded by SLC6A8 gene, is essential for taking up the creatine in the cell, which in turn plays a key role in the spatial and temporal maintenance of energy in skeletal and cardiac muscle cells. It was shown that some missense mutations in CT cause mental retardation, while others are harmless non-synonymous single nucleoside polymorphism (nsSNP). Currently fifteen missense mutations in CT are known, among which twelve are disease-causing. Sequence analysis reveals that there is no clear trend distinguishing disease-causing from harmless missense mutations. Because of that, we built 3D model of the CT using highly homologous template and use the model to investigate the effects of mutations of CT stability and hydrogen bond network. It is demonstrated that disease-causing mutations affect the folding free energy and ionization states of titratable group in much greater extend as compared with harmless mutations. Supported by grants from NLM, NIH, grant numbers 1R03LM009748 and 1R03LM009748-S1.

  7. Epidermal growth factor receptor activation in glioblastoma through novel missense mutations in the extracellular domain.

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    Jeffrey C Lee

    2006-12-01

    Full Text Available BACKGROUND: Protein tyrosine kinases are important regulators of cellular homeostasis with tightly controlled catalytic activity. Mutations in kinase-encoding genes can relieve the autoinhibitory constraints on kinase activity, can promote malignant transformation, and appear to be a major determinant of response to kinase inhibitor therapy. Missense mutations in the EGFR kinase domain, for example, have recently been identified in patients who showed clinical responses to EGFR kinase inhibitor therapy. METHODS AND FINDINGS: Encouraged by the promising clinical activity of epidermal growth factor receptor (EGFR kinase inhibitors in treating glioblastoma in humans, we have sequenced the complete EGFR coding sequence in glioma tumor samples and cell lines. We identified novel missense mutations in the extracellular domain of EGFR in 13.6% (18/132 of glioblastomas and 12.5% (1/8 of glioblastoma cell lines. These EGFR mutations were associated with increased EGFR gene dosage and conferred anchorage-independent growth and tumorigenicity to NIH-3T3 cells. Cells transformed by expression of these EGFR mutants were sensitive to small-molecule EGFR kinase inhibitors. CONCLUSIONS: Our results suggest extracellular missense mutations as a novel mechanism for oncogenic EGFR activation and may help identify patients who can benefit from EGFR kinase inhibitors for treatment of glioblastoma.

  8. Novel OPA1 missense mutation in a family with optic atrophy and severe widespread neurological disorder.

    Science.gov (United States)

    Liskova, Petra; Ulmanova, Olga; Tesina, Petr; Melsova, Hana; Diblik, Pavel; Hansikova, Hana; Tesarova, Marketa; Votruba, Marcela

    2013-05-01

    To identify the underlying molecular genetic cause in a Czech family with optic atrophy, deafness, ptosis, ophthalmoplegia, polyneuropathy and ataxia transmitted as an autosomal dominant trait. Ophthalmological and neurological examination followed by molecular genetic analyses. Seven family members were clinically affected. There was a variable but progressive visual, hearing and neurological disability across the family as a whole. The majority of subjects presented with impairment of visual function and a variable degree of ptosis and/or ophthalmoplegia from the first to the third decade of life. Deafness, neuropathy and ataxia appeared later, in the third and fourth decade. Migraine, tachycardia, intention tremor, nystagmus and cervical dystonia were observed in isolated individuals. A significant overall feature was the high level of neurological disability leading to 3 of 4 members being unable to walk or stand unaided before the age of 60 years. A novel missense mutation c.1345A>C (p.Thr449Pro) in OPA1 segregating with the disease phenotype over three generations was detected. In silico analysis supported pathogenicity of the identified sequence variant. Our work expands the spectrum of mutation in OPA1, which may lead to severe multisystem neurological disorder. The molecular genetic cause of dominant optic atrophy in the Czech population is reported for the first time. We propose that regular cardiac follow-up in patients diagnosed with dominant optic atrophy and widespread neurological disease should be considered. © 2013 The Authors. Acta Ophthalmologica © 2013 Acta Ophthalmologica Scandinavica Foundation.

  9. bfb, a novel ENU-induced blebs mutant resulting from a missense mutation in Fras1.

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    Kerry A Miller

    Full Text Available Fras1 is an extracellular matrix associated protein with essential roles in adhesion of epithelia and mesenchyme during early embryonic development. The adhesive function of Fras1 is achieved through interaction with a group of related proteins, Frem 1-3, and a cytoplasmic adaptor protein Grip1. Mutation of each of these proteins results in characteristic epithelial blistering and have therefore become known as "blebs" proteins. Human Fraser syndrome presents with a similar phenotype and the blebs mice have been instrumental in identification of the genetic basis of Fraser syndrome. We have identified a new ENU-induced blebs allele resulting from a novel missense mutation in Fras1. The resulting mouse strain, blood filled blisters (bfb, presents with a classic blebs phenotype but does not exhibit embryonic lethality typical of other blebs mutants and in addition, we report novel palate and sternal defects. Analysis of the bfb phenotype confirms the presence of epithelial-mesenchymal adhesion defects but also supports the emerging role of blebs proteins in regulating signalling during organogenesis. The bfb strain provides new opportunities to investigate the role of Fras1 in development.

  10. cDNA sequencing improves the detection of P53 missense mutations in colorectal cancer

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    Jesionek-Kupnicka Dorota

    2009-08-01

    Full Text Available Abstract Background Recently published data showed discrepancies beteween P53 cDNA and DNA sequencing in glioblastomas. We hypothesised that similar discrepancies may be observed in other human cancers. Methods To this end, we analyzed 23 colorectal cancers for P53 mutations and gene expression using both DNA and cDNA sequencing, real-time PCR and immunohistochemistry. Results We found P53 gene mutations in 16 cases (15 missense and 1 nonsense. Two of the 15 cases with missense mutations showed alterations based only on cDNA, and not DNA sequencing. Moreover, in 6 of the 15 cases with a cDNA mutation those mutations were difficult to detect in the DNA sequencing, so the results of DNA analysis alone could be misinterpreted if the cDNA sequencing results had not also been available. In all those 15 cases, we observed a higher ratio of the mutated to the wild type template by cDNA analysis, but not by the DNA analysis. Interestingly, a similar overexpression of P53 mRNA was present in samples with and without P53 mutations. Conclusion In terms of colorectal cancer, those discrepancies might be explained under three conditions: 1, overexpression of mutated P53 mRNA in cancer cells as compared with normal cells; 2, a higher content of cells without P53 mutation (normal cells and cells showing K-RAS and/or APC but not P53 mutation in samples presenting P53 mutation; 3, heterozygous or hemizygous mutations of P53 gene. Additionally, for heterozygous mutations unknown mechanism(s causing selective overproduction of mutated allele should also be considered. Our data offer new clues for studying discrepancy in P53 cDNA and DNA sequencing analysis.

  11. Missense Mutations in Exons 18–24 of EGFR in Hepatocellular Carcinoma Tissues

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    Ravat Panvichian

    2015-01-01

    Full Text Available Epidermal growth factor receptor (EGFR, a transmembrane tyrosine kinase receptor, plays important roles in various cancers. In nonsmall cell lung cancer (NSCLC, EGFR mutations cluster around the ATP-binding pocket (exons 18–21 and some of these mutations activate the kinase and induce an increased sensitivity to EGFR-tyrosine kinase inhibitors. Nevertheless, data of EGFR mutations in HCC are limited. In this study, we investigated EGFR expression by immunohistochemistry and EGFR mutations (exons 18–24 by PCR cloning and sequencing. EGFR overexpression in HCC and matched nontumor tissues were detected in 13/40 (32.5% and 10/35 (28.6%, respectively. Moreover, missense and silent mutations were detected in 13/33 (39.4% and 11/33 (33.3% of HCC tissues, respectively. The thirteen different missense mutations were p.L730P, p.V742I, p.K757E, p.I780T, p.N808S, p.R831C, p.V851A, p.V897A, p.S912P, p.P937L, p.T940A, p.M947V, and p.M947T. We also found already known SNP, p.Q787Q (CAG>CAA, in 13/33 (39.4% of HCC tissues. However, no significant association was detected between EGFR mutations and EGFR overexpression, tissue, age, sex, tumor size, AFP, HBsAg, TP53, and Ki-67. Further investigation is warranted to validate the frequency and activity of these missense mutations, as well as their roles in HCC tumorigenesis and in EGFR-targeted therapy.

  12. A missense mutation in PMEL17 is associated with the Silver coat color in the horse

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    Cothran Gus

    2006-10-01

    Full Text Available Abstract Background The Silver coat color, also called Silver dapple, in the horse is characterized by dilution of the black pigment in the hair. This phenotype shows an autosomal dominant inheritance. The effect of the mutation is most visible in the long hairs of the mane and tail, which are diluted to a mixture of white and gray hairs. Herein we describe the identification of the responsible gene and a missense mutation associated with the Silver phenotype. Results Segregation data on the Silver locus (Z were obtained within one half-sib family that consisted of a heterozygous Silver colored stallion with 34 offspring and their 29 non-Silver dams. We typed 41 genetic markers well spread over the horse genome, including one single microsatellite marker (TKY284 close to the candidate gene PMEL17 on horse chromosome 6 (ECA6q23. Significant linkage was found between the Silver phenotype and TKY284 (θ = 0, z = 9.0. DNA sequencing of PMEL17 in Silver and non-Silver horses revealed a missense mutation in exon 11 changing the second amino acid in the cytoplasmic region from arginine to cysteine (Arg618Cys. This mutation showed complete association with the Silver phenotype across multiple horse breeds, and was not found among non-Silver horses with one clear exception; a chestnut colored individual that had several Silver offspring when mated to different non-Silver stallions also carried the exon 11 mutation. In total, 64 Silver horses from six breeds and 85 non-Silver horses from 14 breeds were tested for the exon 11 mutation. One additional mutation located in intron 9, only 759 bases from the missense mutation, also showed complete association with the Silver phenotype. However, as one could expect to find several non-causative mutations completely associated with the Silver mutation, we argue that the missense mutation is more likely to be causative. Conclusion The present study shows that PMEL17 causes the Silver coat color in the horse and

  13. Missense mutations in progranulin gene associated with frontotemporal lobar degeneration: study of pathogenetic features.

    Science.gov (United States)

    Karch, Celeste M; Ezerskiy, Lubov; Redaelli, Veronica; Giovagnoli, Anna Rita; Tiraboschi, Pietro; Pelliccioni, Giuseppe; Pelliccioni, Paolo; Kapetis, Dimos; D'Amato, Ilaria; Piccoli, Elena; Ferretti, Maria Giulia; Tagliavini, Fabrizio; Rossi, Giacomina

    2016-02-01

    GRN, the gene coding for the progranulin (PGRN) protein, was recognized as a gene linked to frontotemporal lobar degeneration (FTLD). The first mutations identified were null mutations giving rise to haploinsufficiency. Missense mutations were subsequently detected, but only a small subset has been functionally investigated. We identified missense mutations (C105Y, A199V, and R298H) in FTLD cases with family history and/or with low plasma PGRN levels. The aim of this study was to determine their pathogenicity. We performed functional studies, analyzing PGRN expression, secretion, and cleavage by elastase. GRN C105Y affected both secretion and elastase cleavage, likely representing a pathogenic mutation. GRN A199V did not alter the physiological properties of PGRN and GRN R298H produced only moderate effects on PGRN secretion, indicating that their pathogenicity is uncertain. In the absence of strong segregation data and neuropathological examinations, genetic, biomarker, and functional studies can be applied to an algorithm to assess the likelihood of pathogenicity for a mutation. This information can improve our understanding of the complex mechanisms by which GRN mutations lead to FTLD.

  14. Congenital immunodeficiency in an individual with Wiedemann-Steiner syndrome due to a novel missense mutation in KMT2A.

    Science.gov (United States)

    Stellacci, Emilia; Onesimo, Roberta; Bruselles, Alessandro; Pizzi, Simone; Battaglia, Domenica; Leoni, Chiara; Zampino, Giuseppe; Tartaglia, Marco

    2016-09-01

    Wiedemann-Steiner Syndrome (WSS) is an autosomal dominant disorder characterized by hypertrichosis, short stature, intellectual disability, developmental delay, and facial dysmorphism. Since the original reports by Wiedemann and co-workers, and Steiner and Marques, only a few cases have been described. Recently, the clinical variability of the disorder has more precisely been characterized by Jones and co-workers, who also identified heterozygous KMT2A mutations as the molecular defect underlying this condition. Here, we report on a boy with a complex phenotype overlapping WSS but exhibiting epilepsy, feeding difficulties, microcephaly, and congenital immunodeficiency with low levels of immunoglobulins as additional features. Whole exome sequencing allowed identifying a previously unreported de novo KMT2A missense mutation affecting the DNA binding domain of the methyltransferase. This finding expands the clinical phenotype associated with KMT2A mutations to include immunodeficiency and epilepsy as clinically relevant features for this disorder. © 2016 Wiley Periodicals, Inc.

  15. Association of KCNJ5 gene missense mutations with aldosterone-producing adenoma and primary hyperaldosteronism

    Institute of Scientific and Technical Information of China (English)

    邵丹

    2013-01-01

    Objective To detect the KCNJ5 gene variations in aldosterone-producing adenoma (APA) with primary hyperaldosteronism (PA) ,and to investigate the association of the KCNJ5 gene missense mutations with APA and PA.Methods A total of 46 APA tumors and their clinical characteristics were collected from Hypertension Center of the People’s Hospital of Xinjiang Uygur Autonomous Region,and all the tumors were confirmed by pathology.

  16. A newly identified missense mutation in RET codon 666 is associated with the development of medullary thyroid carcinoma.

    Science.gov (United States)

    Yamazaki, Masanori; Hanamura, Toru; Ito, Ken-ichi; Uchino, Shinya; Sakurai, Akihiro; Komatsu, Mitsuhisa

    2014-01-01

    A 38-year-old woman with a thyroid nodule measuring approximately 2 cm was suspected to have medullary thyroid carcinoma (MTC) because of markedly elevated serum calcitonin and carcinoembryonic antigen levels. There were no signs of pheochromocytoma, whereas primary hyperparathyroidism was suspected based on the findings of inappropriate hypersecretion of parathyroid hormone although no parathyroid tumor was detected with imaging studies. RET mutation analysis revealed a novel germline missense mutation in codon 666, c.1997A>G (p.K666R). She underwent total thyroidectomy with lymphadenectomy and simultaneous total parathyroidectomy with autotransplantation of parathyroid tissue. She was given calcium lactate and alfacalcidol to prevent postoperative hypocalcemia. Pathological findings of the thyroid tumor were compatible with MTC, but the resected parathyroid glands were intact. To our knowledge, c.1997A>G (p.K666R) is a new RET mutation. This is a minor variant, but it is significant because of the possible pathogenicity in tumor formation. It is often difficult to determine whether MTC is generated as part of MEN2-related disease or familial MTC when it is a unique manifestation. In addition, it is still unclear whether all missense mutations in this codon reported previously will lead to the same clinical course and prognosis. Further careful observations of clinical presentation are required to determine the clinical features associated with this variant.

  17. Missense mutations in the gene encoding prothrombin corresponding to Arg596 cause antithrombin resistance and thrombomodulin resistance.

    Science.gov (United States)

    Takagi, Yuki; Murata, Moe; Kozuka, Toshihiro; Nakata, Yukiko; Hasebe, Ryo; Tamura, Shogo; Takagi, Akira; Matsushita, Tadashi; Saito, Hidehiko; Kojima, Tetsuhito

    2016-11-30

    Antithrombin (AT) and thrombomodulin (TM) play important roles in the process of natural anticoagulation in vivo. Recently, we reported that the prothrombin Yukuhashi mutation (p.Arg596Leu) was associated with AT and TM resistance-related thrombophilia. To assess the AT and TM resistances associated with other missense mutations by single base substitution in the Arg596 codon, we generated recombinant variants (596Gln, 596Trp, 596Gly, and 596Pro) and investigated the effects on AT and TM anticoagulant functions. All variants except 596Pro were secreted in amounts comparable to that of the wild-type but exhibited variable procoagulant activities. After a 30-minute inactivation by AT, the relative residual activity of wild-type thrombin decreased to 15 ± 4.0 %, in contrast to values of all variants were maintained at above 80 %. The thrombin-AT complex formation, as determined by enzyme-linked immunosorbent assay, was reduced with all tested variants in the presence and absence of heparin. In the presence of soluble TM (sTM), the relative fibrinogen clotting activity of wild-type thrombin decreased to 16 ± 0.12 %, whereas that of tested variants was 37 %-56 %. In a surface plasmon resonance assay, missense Arg596 mutations reduced thrombin-TM affinity to an extent similar to the reduction of fibrinogen clotting inhibition. In the presence of sTM or cultured endothelial-like cells, APC generation was enhanced differently by variant thrombins in a thrombin-TM affinity-dependent manner. These data indicate that prothrombin Arg596 missense mutations lead to AT and TM resistance in the variant thrombins and suggest that prothrombin Arg596 is important for AT- and TM-mediated anticoagulation.

  18. Severe Clinical Course in a Patient with Congenital Amegakaryocytic Thrombocytopenia Due to a Missense Mutation of the c-MPL Gene

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    İkbal Ok Bozkaya

    2015-06-01

    Full Text Available Congenital amegakaryocytic thrombocytopenia (CAMT generally begins at birth with severe thrombocytopenia and progresses to pancytopenia. It is caused by mutations in the thrombopoietin receptor gene, the myeloproliferative leukemia virus oncogene (c-MPL. The association between CAMT and c-MPL mutation type has been reported in the literature. Patients with CAMT have been categorized according to their clinical symptoms caused by different mutations. Missense mutations of c-MPL have been classified as type II and these patients have delayed onset of bone marrow failure compared to type I patients. Here we present a girl with severe clinical course of CAMT II having a missense mutation in exon 4 of the c-MPL gene who was admitted to our hospital with intracranial hemorrhage during the newborn period.

  19. Theoretical prediction of familial amyotrophic lateral sclerosis missense mutation effects on Cu/Zn superoxide dismutase structural stability

    Energy Technology Data Exchange (ETDEWEB)

    Potier, M.; Tu, Y. [Universite de Montreal, Quebec (Canada)

    1994-09-01

    Cu/Zn superoxide dismutase (SOD) deficiency is associated with the progressive paralytic disorder familial amyotrophic lateral sclerosis (FALS). Fifteen missense mutations in the SOD gene were identified in several patients. These mutations may prevent correct promoter folding or hamper homodimer formation necessary for SOD activity. To understand the effect of the missense mutations on SOD structure and function, we used a theoretical analysis of structural effects based on two predictive methods using the modeled tertiary structure of human SOD. The first method uses the TORSO program which optimizes amino acid side-chains repacking in both wild-type and mutant SODs and calculates protein internal packing energy. The second method uses a hydrophobicity scale of the amino acid residues and considers both solvent accessibility and hydrophobic nature of residue substitutions to compute a stabilization energy change ({delta}E). These predictive methods have been tested in 187 single and multiple missense mutants of 8 proteins (T4 lysozyme, human carbonic anhydrase II, chymotrypsin inhibitor 2, f1 gene V protein, barnase, {lambda}-repressor, chicken and human lysozymes) with experimentally determined thermostability. The overall prediction accuracy with these proteins was 88%. Analysis of FALS missense mutations {delta}E predicts that 14 of 15 mutations destabilize the SOD structure. The other missense mutation is located at the homodimer interface and may hinder dimer formation. This approach is applicable to any protein with known tertiary structure to predict missense mutation effects on protein stability.

  20. A missense mutation in PIK3R5 gene in a family with ataxia and oculomotor apraxia.

    Science.gov (United States)

    Al Tassan, Nada; Khalil, Dania; Shinwari, Jameela; Al Sharif, Latifa; Bavi, Prashant; Abduljaleel, Zainularifeen; Abu Dhaim, Nada; Magrashi, Amna; Bobis, Steve; Ahmed, Hala; Alahmed, Samaher; Bohlega, Saeed

    2012-02-01

    Autosomal recessive ataxias are heterogeneous group of disorders characterized by cerebellar atrophy and peripheral sensorimotor neuropathy. Molecular characterization of this group of disorders identified a number of genes contributing to these overlapping phenotypes. Ataxia with oculomotor apraxia type 2 (AOA2) is an autosomal recessive form of ataxia caused by mutations in the SETX gene. We report on a consanguineous family with autosomal recessive inheritance and clinical characteristics of AOA2, and no mutations in the SETX gene. We mapped the AOA locus in this family to chromosome 17p12-p13. Sequencing of all genes in the refined region identified a homozygous missense mutation in PIK3R5 that was absent in 477 normal controls. Our characterization of the PIK3R5 protein and findings suggest that it may play a role in the development of the cerebellum and vermis.

  1. Hereditary thrombophilia: identification of nonsense and missense mutations in the protein C gene

    Energy Technology Data Exchange (ETDEWEB)

    Romeo, G.; Hassan, H.J.; Staempfli, S.; Roncuzzi, L.; Cianetti, L.; Leonardi, A.; Vicente, V.; Mannucci, P.M.; Bertina, R.; Peschile, C.; Cortese, R.

    1987-05-01

    The structure of the gene for protein C, an anticoagulant serine protease, was analyzed in 29 unrelated patients with hereditary thrombophilia and protein C deficiency. Gene deletion(s) or gross rearrangement(s) was not demonstrable by Southern blot hybridization to cDNA probes. However, two unrelated patients showed a variant restriction pattern after Pvu II or BamHi digestion, due to mutations in the last exon: analysis of their pedigrees, including three or seven heterozygotes, respectively, with approx.50% reduction of both enzymatic and antigen level, showed the abnormal restriction pattern in all heterozygous individuals, but not in normal relatives. Cloning of protein C gene and sequencing of the last exon allowed the authors to identify a nonsense and a missense mutation, respectively. In the first case, codon 306 (CGA, arginine) is mutated to an inframe stop codon, thus generating a new Pvu II recognition site. In the second case, a missense mutation in the BamHI palindrome (GGATCC ..-->.. GCATCC) leads to substitution of a key amino acid (a tryptophan to cysteine substitution at position 402), invariantly conserved in eukaryotic serine proteases. These point mutations may explain the protein C-deficiency phenotype of heterozygotes in the two pedigrees.

  2. Structural and functional analyses of disease-causing missense mutations in Bloom syndrome protein.

    Science.gov (United States)

    Guo, Rong-Bing; Rigolet, Pascal; Ren, Hua; Zhang, Bo; Zhang, Xing-Dong; Dou, Shuo-Xing; Wang, Peng-Ye; Amor-Gueret, Mounira; Xi, Xu Guang

    2007-01-01

    Bloom syndrome (BS) is an autosomal recessive disorder characterized by genomic instability and the early development of many types of cancer. Missense mutations have been identified in the BLM gene (encoding a RecQ helicase) in affected individuals, but the molecular mechanism and the structural basis of the effects of these mutations remain to be elucidated. We analysed five disease-causing missense mutations that are localized in the BLM helicase core region: Q672R, I841T, C878R, G891E and C901Y. The disease-causing mutants had low ATPase and helicase activities but their ATP binding abilities were normal, except for Q672, whose ATP binding activity was lower than that of the intact BLM helicase. Mutants C878R, mapping near motif IV, and G891E and C901Y, mapping in motif IV, displayed severe DNA-binding defects. We used molecular modelling to analyse these mutations. Our work provides insights into the molecular basis of BLM pathology, and reveals structural elements implicated in coupling DNA binding to ATP hydrolysis and DNA unwinding. Our findings will help to explain the mechanism underlying BLM catalysis and interpreting new BLM causing mutations identified in the future.

  3. Proteasomal Inhibition Restores Biological Function of Mis-sense Mutated Dysferlin in Patient-derived Muscle Cells*

    Science.gov (United States)

    Azakir, Bilal A.; Di Fulvio, Sabrina; Kinter, Jochen; Sinnreich, Michael

    2012-01-01

    Dysferlin is a transmembrane protein implicated in surface membrane repair of muscle cells. Mutations in dysferlin cause the progressive muscular dystrophies Miyoshi myopathy, limb girdle muscular dystrophy 2B, and distal anterior compartment myopathy. Dysferlinopathies are inherited in an autosomal recessive manner, and many patients with this disease harbor mis-sense mutations in at least one of their two pathogenic DYSF alleles. These patients have significantly reduced or absent dysferlin levels in skeletal muscle, suggesting that dysferlin encoded by mis-sense alleles is rapidly degraded by the cellular quality control system. We reasoned that mis-sense mutated dysferlin, if salvaged from degradation, might be biologically functional. We used a dysferlin-deficient human myoblast culture harboring the common R555W mis-sense allele and a DYSF-null allele, as well as control human myoblast cultures harboring either two wild-type or two null alleles. We measured dysferlin protein and mRNA levels, resealing kinetics of laser-induced plasmalemmal wounds, myotube formation, and cellular viability after treatment of the human myoblast cultures with the proteasome inhibitors lactacystin or bortezomib (Velcade). We show that endogenous R555W mis-sense mutated dysferlin is degraded by the proteasomal system. Inhibition of the proteasome by lactacystin or Velcade increases the levels of R555W mis-sense mutated dysferlin. This salvaged protein is functional as it restores plasma membrane resealing in patient-derived myoblasts and reverses their deficit in myotube formation. Bortezomib and lactacystin did not cause cellular toxicity at the regimen used. Our results raise the possibility that inhibition of the degradation pathway of mis-sense mutated dysferlin could be used as a therapeutic strategy for patients harboring certain dysferlin mis-sense mutations. PMID:22318734

  4. Proteasomal inhibition restores biological function of mis-sense mutated dysferlin in patient-derived muscle cells.

    Science.gov (United States)

    Azakir, Bilal A; Di Fulvio, Sabrina; Kinter, Jochen; Sinnreich, Michael

    2012-03-23

    Dysferlin is a transmembrane protein implicated in surface membrane repair of muscle cells. Mutations in dysferlin cause the progressive muscular dystrophies Miyoshi myopathy, limb girdle muscular dystrophy 2B, and distal anterior compartment myopathy. Dysferlinopathies are inherited in an autosomal recessive manner, and many patients with this disease harbor mis-sense mutations in at least one of their two pathogenic DYSF alleles. These patients have significantly reduced or absent dysferlin levels in skeletal muscle, suggesting that dysferlin encoded by mis-sense alleles is rapidly degraded by the cellular quality control system. We reasoned that mis-sense mutated dysferlin, if salvaged from degradation, might be biologically functional. We used a dysferlin-deficient human myoblast culture harboring the common R555W mis-sense allele and a DYSF-null allele, as well as control human myoblast cultures harboring either two wild-type or two null alleles. We measured dysferlin protein and mRNA levels, resealing kinetics of laser-induced plasmalemmal wounds, myotube formation, and cellular viability after treatment of the human myoblast cultures with the proteasome inhibitors lactacystin or bortezomib (Velcade). We show that endogenous R555W mis-sense mutated dysferlin is degraded by the proteasomal system. Inhibition of the proteasome by lactacystin or Velcade increases the levels of R555W mis-sense mutated dysferlin. This salvaged protein is functional as it restores plasma membrane resealing in patient-derived myoblasts and reverses their deficit in myotube formation. Bortezomib and lactacystin did not cause cellular toxicity at the regimen used. Our results raise the possibility that inhibition of the degradation pathway of mis-sense mutated dysferlin could be used as a therapeutic strategy for patients harboring certain dysferlin mis-sense mutations.

  5. A missense mutation in the dystrophin gene in a Duchenne muscular dystrophy patient.

    Science.gov (United States)

    Prior, T W; Papp, A C; Snyder, P J; Burghes, A H; Bartolo, C; Sedra, M S; Western, L M; Mendell, J R

    1993-08-01

    About two thirds of Duchenne muscular dystrophy (DMD) patients have either gene deletions or duplications. The other DMD cases are most likely the result of point mutations that cannot be easily identified by current strategies. Utilizing a heteroduplex technique and direct sequencing of amplified products, we screened our nondeletion/duplication DMD population for point mutations. We now describe what we believe to be the first dystrophin missense mutation in a DMD patient. The mutation results in the substitution of an evolutionarily conserved leucine to arginine in the actin-binding domain. The patient makes a dystrophin protein which is properly localized and is present at a higher level than is observed in DMD patients. This suggests that an intact actin-binding domain is necessary for protein stability and essential for function.

  6. Missense mutations in ITPR1 cause autosomal dominant congenital nonprogressive spinocerebellar ataxia

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    Huang Lijia

    2012-09-01

    Full Text Available Abstract Background Congenital nonprogressive spinocerebellar ataxia is characterized by early gross motor delay, hypotonia, gait ataxia, mild dysarthria and dysmetria. The clinical presentation remains fairly stable and may be associated with cerebellar atrophy. To date, only a few families with autosomal dominant congenital nonprogressive spinocerebellar ataxia have been reported. Linkage to 3pter was demonstrated in one large Australian family and this locus was designated spinocerebellar ataxia type 29. The objective of this study is to describe an unreported Canadian family with autosomal dominant congenital nonprogressive spinocerebellar ataxia and to identify the underlying genetic causes in this family and the original Australian family. Methods and Results Exome sequencing was performed for the Australian family, resulting in the identification of a heterozygous mutation in the ITPR1 gene. For the Canadian family, genotyping with microsatellite markers and Sanger sequencing of ITPR1 gene were performed; a heterozygous missense mutation in ITPR1 was identified. Conclusions ITPR1 encodes inositol 1,4,5-trisphosphate receptor, type 1, a ligand-gated ion channel that mediates calcium release from the endoplasmic reticulum. Deletions of ITPR1 are known to cause spinocerebellar ataxia type 15, a distinct and very slowly progressive form of cerebellar ataxia with onset in adulthood. Our study demonstrates for the first time that, in addition to spinocerebellar ataxia type 15, alteration of ITPR1 function can cause a distinct congenital nonprogressive ataxia; highlighting important clinical heterogeneity associated with the ITPR1 gene and a significant role of the ITPR1-related pathway in the development and maintenance of the normal functions of the cerebellum.

  7. Phenotypic variability in 49 cases of ESCO2 mutations, including novel missense and codon deletion in the acetyltransferase domain, correlates with ESCO2 expression and establishes the clinical criteria for Roberts syndrome

    DEFF Research Database (Denmark)

    Vega, H; Trainer, A H; Gordillo, M;

    2010-01-01

    Roberts syndrome (RBS) and SC phocomelia are caused by mutations in ESCO2, which codes for an acetyltransferase involved in the regulation of sister chromatid cohesion. Of 26 mutations described to date, only one missense mutation has been reported and all others are predicted to be truncating...

  8. Phenotypic variability in 49 cases of ESCO2 mutations, including novel missense and codon deletion in the acetyltransferase domain, correlates with ESCO2 expression and establishes the clinical criteria for Roberts syndrome

    NARCIS (Netherlands)

    Vega, H.; Trainer, A.H.; Gordillo, M.; Crosier, M.; Kayserili, H.; Skovby, F.; Uzielli, M.L.G.; Schnur, R.E.; Manouvrier, S.; Blair, E.; Hurst, J.A.; Forzano, F.; Meins, M.; Simola, K.O.J.; Raas-Rothschild, A; Hennekam, R.C.M.; Jabs, E.W.

    2010-01-01

    Background Roberts syndrome (RBS) and SC phocomelia are caused by mutations in ESCO2, which codes for an acetyltransferase involved in the regulation of sister chromatid cohesion. Of 26 mutations described to date, only one missense mutation has been reported and all others are predicted to be trunc

  9. Phenotypic variability in 49 cases of ESCO2 mutations, including novel missense and codon deletion in the acetyltransferase domain, correlates with ESCO2 expression and establishes the clinical criteria for Roberts syndrome

    DEFF Research Database (Denmark)

    Vega, H; Trainer, A H; Gordillo, M;

    2010-01-01

    Roberts syndrome (RBS) and SC phocomelia are caused by mutations in ESCO2, which codes for an acetyltransferase involved in the regulation of sister chromatid cohesion. Of 26 mutations described to date, only one missense mutation has been reported and all others are predicted to be truncating mu...

  10. WDR73 missense mutation causes infantile onset intellectual disability and cerebellar hypoplasia in a consanguineous family.

    Science.gov (United States)

    Jiang, Chen; Gai, Nan; Zou, Yongyi; Zheng, Yu; Ma, Ruiyu; Wei, Xianda; Liang, Desheng; Wu, Lingqian

    2017-01-01

    Galloway-Mowat syndrome (GMS) is a very rare autosomal-recessive disorder characterized by nephrotic syndrome associated with microcephaly, and various central nervous system abnormalities, mostly cerebral hypoplasia or cerebellar atrophy, intellectual disability and neural-migration defects. WDR73 is the only gene known to cause GMS, and has never been implicated in other disease. Here we present a Chinese consanguineous family with infantile onset intellectual disability and cerebellar hypoplasia but no microcephaly. Whole exome sequencing identified a WDR73 p.W371G missense mutation. The mutation is confirmed to be segregated in this family by Sanger sequencing according to a recessive inheritance pattern. It is predicted to be deleterious by multiple algorithms and affect highly conserved site. Structural modeling revealed conformational differences between the wild type protein and the p.W371G protein. Real-time PCR and Western blotting revealed altered mRNA and protein levels in mutated samples. Our study indicates the novel WDR73 p.W371G missense mutation causes infantile onset intellectual disability and cerebellar hypoplasia in recessive mode of inheritance. Our findings imply that microcephaly is a variable phenotype in WDR73-related disease, suggest WDR73 to be a candidate gene of severe intellectual disability and cerebellar hypoplasia, and expand the molecular spectrum of WDR73-related disease.

  11. A missense mutation (Q279R in the Fumarylacetoacetate Hydrolase gene, responsible for hereditary tyrosinemia, acts as a splicing mutation

    Directory of Open Access Journals (Sweden)

    Baklouti Faouzi

    2001-06-01

    Full Text Available Abstract Background Tyrosinemia type I, the most severe disease of the tyrosine catabolic pathway is caused by a deficiency in fumarylacetoacetate hydrolase (FAH. A patient showing few of the symptoms associated with the disease, was found to be a compound heterozygote for a splice mutation, IVS6-1g->t, and a putative missense mutation, Q279R. Analysis of FAH expression in liver sections obtained after resection for hepatocellular carcinoma revealed a mosaic pattern of expression. No FAH was found in tumor regions while a healthy region contained enzyme-expressing nodules. Results Analysis of DNA from a FAH expressing region showed that the expression of the protein was due to correction of the Q279R mutation. RT-PCR was used to assess if Q279R RNA was produced in the liver cells and in fibroblasts from the patient. Normal mRNA was found in the liver region where the mutation had reverted while splicing intermediates were found in non-expressing regions suggesting that the Q279R mutation acted as a splicing mutation in vivo. Sequence of transcripts showed skipping of exon 8 alone or together with exon 9. Using minigenes in transfection assays, the Q279R mutation was shown to induce skipping of exon 9 when placed in a constitutive splicing environment. Conclusion These data suggest that the putative missense mutation Q279R in the FAH gene acts as a splicing mutation in vivo. Moreover FAH expression can be partially restored in certain liver cells as a result of a reversion of the Q279R mutation and expansion of the corrected cells.

  12. Prediction of phenotypes of missense mutations in human proteins from biological assemblies.

    Science.gov (United States)

    Wei, Qiong; Xu, Qifang; Dunbrack, Roland L

    2013-02-01

    Single nucleotide polymorphisms (SNPs) are the most frequent variation in the human genome. Nonsynonymous SNPs that lead to missense mutations can be neutral or deleterious, and several computational methods have been presented that predict the phenotype of human missense mutations. These methods use sequence-based and structure-based features in various combinations, relying on different statistical distributions of these features for deleterious and neutral mutations. One structure-based feature that has not been studied significantly is the accessible surface area within biologically relevant oligomeric assemblies. These assemblies are different from the crystallographic asymmetric unit for more than half of X-ray crystal structures. We find that mutations in the core of proteins or in the interfaces in biological assemblies are significantly more likely to be disease-associated than those on the surface of the biological assemblies. For structures with more than one protein in the biological assembly (whether the same sequence or different), we find the accessible surface area from biological assemblies provides a statistically significant improvement in prediction over the accessible surface area of monomers from protein crystal structures (P = 6e-5). When adding this information to sequence-based features such as the difference between wildtype and mutant position-specific profile scores, the improvement from biological assemblies is statistically significant but much smaller (P = 0.018). Combining this information with sequence-based features in a support vector machine leads to 82% accuracy on a balanced dataset of 50% disease-associated mutations from SwissVar and 50% neutral mutations from human/primate sequence differences in orthologous proteins.

  13. Assessing the pathogenic potential of human Nephronophthisis disease-associated NPHP-4 missense mutations in C. elegans.

    Science.gov (United States)

    Masyukova, Svetlana V; Winkelbauer, Marlene E; Williams, Corey L; Pieczynski, Jay N; Yoder, Bradley K

    2011-08-01

    A spectrum of complex oligogenic disorders called the ciliopathies have been connected to dysfunction of cilia. Among the ciliopathies are Nephronophthisis (NPHP), characterized by cystic kidney disease and retinal degeneration, and Meckel-Gruber syndrome (MKS), a gestational lethal condition with skeletal abnormalities, cystic kidneys and CNS malformation. Mutations in multiple genes have been identified in NPHP and MKS patients, and an unexpected finding has been that mutations within the same gene can cause either disorder. Further, there is minimal genotype-phenotype correlation and despite recessive inheritance, numerous patients were identified as having a single heterozygous mutation. This has made it difficult to determine the significance of these mutations on disease pathogenesis and led to the hypothesis that clinical presentation in an individual will be determined by genetic interactions between mutations in multiple cilia-related genes. Here we utilize Caenorhabditis elegans and cilia-associated behavioral and morphologic assays to evaluate the pathogenic potential of eight previously reported human NPHP4 missense mutations. We assess the impact of these mutations on C. elegans NPHP-4 function, localization and evaluate potential interactions with mutations in MKS complex genes, mksr-2 and mksr-1. Six out of eight nphp-4 mutations analyzed alter ciliary function, and three of these modify the severity of the phenotypes caused by disruption of mksr-2 and mksr-1. Collectively, our studies demonstrate the utility of C. elegans as a tool to assess the pathogenicity of mutations in ciliopathy genes and provide insights into the complex genetic interactions contributing to the diversity of phenotypes associated with cilia disorders.

  14. Altered-function p53 missense mutations identified in breast cancers can have subtle effects on transactivation

    Science.gov (United States)

    Jordan, Jennifer J.; Inga, Alberto; Conway, Kathleen; Edmiston, Sharon; Carey, Lisa A.; Wu, Lin; Resnick, Michael A.

    2010-01-01

    Mutations of the sequence-specific master regulator p53 that alter transactivation function from promoter response elements (REs) could result in changes in the strength of gene activation or spectra of genes regulated. Such mutations in this tumor suppressor might lead to dramatic phenotypic changes and diversification of cell responses to stress. We have determined “functional fingerprints” of sporadic breast cancer-related p53 mutants many of which are also associated with familial cancer proneness such as the Li-Fraumeni Syndrome and germline BRCA1/2 mutant-associated cancers. The ability of p53, wild type and mutants, to transactivate from 11 human target REs has been assessed at variable expression levels using a cellular, isogenomic yeast model system that allows for the rapid analysis of p53 function using a qualitative and a quantitative reporter. Among 50 missense mutants, 29 were classified as loss-of-function. The remaining 21 retained transactivation towards at least one RE. At high levels of galactose induced p53 expression, 12/21 mutants that retain transactivation appeared similar to WT. When the level of galactose was reduced, transactivation defects could be revealed suggesting that some breast cancer related mutants can have subtle changes in transcription. These findings have been compared with clinical data from an ongoing neoadjuvant chemotherapy treatment trial for locally advanced breast tumors. The functional and nonfunctional missense mutations may distinguish tumors in terms of demographics, appearance and relapse, implying that heterogeneity in the functionality of specific p53 mutations could impact clinical behavior and outcome. PMID:20407015

  15. DNA analysis of an uncommon missense mutation in a Gaucher disease patient of Jewish-Polish-Russian descent

    Energy Technology Data Exchange (ETDEWEB)

    Choy, F.Y.M.; Wei, C.; Applegarth, D.A.; McGillivray, B.C. [Univ. of British Columbia, Vancouver (Canada)

    1994-06-01

    Gaucher disease is the most frequent lysosomal lipid storage disease. It results from deficient glucocerebrosidase activity and is transmitted as an autosomal recessive trait. Three clinical forms of Gaucher disease have been described: type 1, non-neuronopathic; type 2, acute neuronopathic; and type 3, subacute neuronopathic. We have sequenced the full length cDNA of the glucocerebrosidase gene and identified an uncommon mutation in nucleotide position 1604 (genoma DNA nucleotide position 6683) from a Gaucher disease patient of Jewish-Polish-Russian descent with type 1 Gaucher disease. It is a G{yields}A transition in exon 11 that results in {sup 496}Arg{yields}{sup 496}His of glucocerebrosidase. This missense mutation is present in the heterozygous form and creates a new cleavage site for the endonuclease HphI. We have developed a simple method to detect the presence of this mutation by using HphI restriction fragment length polymorphism analysis of glucocerebrosidase genomic DNA or cDNA. The mutation in the other Gaucher allele of this patient is an A{yields}G transition at cDNA nucleotide position 1226 which creates an XhoI cleavage site after PCR mismatch amplification. The presence of this mutation was also confirmed by sequence analysis. Based on previous reports that mutation 1226 is present only in type 1 Gaucher disease and the observation that there is no neurological involvement in this patient, we conclude that our patient with the 1226/1604 genotype is diagnosed as having type 1 Gaucher disease. Since it was also postulated that mutation 1226 in the homozygous form will usually result in a good prognosis, we speculate that the orthopedic complications and the unusual presence of glomerulosclerosis in this patient may be attributable to the mutation at nucleotide 1604. This speculation will require a description of more patients with this mutation for confirmation. 32 refs., 5 figs.

  16. A novel COL11A1 missense mutation in siblings with non-ocular Stickler syndrome.

    Science.gov (United States)

    Kohmoto, Tomohiro; Tsuji, Atsumi; Morita, Kei-Ichi; Naruto, Takuya; Masuda, Kiyoshi; Kashimada, Kenichi; Enomoto, Keisuke; Morio, Tomohiro; Harada, Hiroyuki; Imoto, Issei

    2016-01-01

    Stickler syndrome (STL) is an autosomal, dominantly inherited, clinically variable and genetically heterogeneous connective tissue disorder characterized by ocular, auditory, orofacial and skeletal abnormalities. We conducted targeted resequencing using a next-generation sequencer for molecular diagnosis of a 2-year-old girl who was clinically suspected of having STL with Pierre Robin sequence. We detected a novel heterozygous missense mutation, NM_001854.3:n.4838G>A [NM_001854.3 (COL11A1_v001):c.4520G>A], in COL11A1, resulting in a Gly to Asp substitution at position 1507 [NM_001854.3(COL11A1_i001)] within one of the collagen-like domains of the triple helical region. The same mutation was detected in her 4-year-old brother with cleft palate and high-frequency sensorineural hearing loss.

  17. Systematic Review of Cysteine-Sparing NOTCH3 Missense Mutations in Patients with Clinical Suspicion of CADASIL

    Directory of Open Access Journals (Sweden)

    Elena Muiño

    2017-09-01

    Full Text Available CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy is caused by mutations in the NOTCH3 gene, affecting the number of cysteines in the extracellular domain of the receptor, causing protein misfolding and receptor aggregation. The pathogenic role of cysteine-sparing NOTCH3 missense mutations in patients with typical clinical CADASIL syndrome is unknown. The aim of this article is to describe these mutations to clarify if any could be potentially pathogenic. Articles on cysteine-sparing NOTCH3 missense mutations in patients with clinical suspicion of CADASIL were reviewed. Mutations were considered potentially pathogenic if patients had: (a typical clinical CADASIL syndrome; (b diffuse white matter hyperintensities; (c the 33 NOTCH3 exons analyzed; (d mutations that were not polymorphisms; and (e Granular osmiophilic material (GOM deposits in the skin biopsy. Twenty-five different mutations were listed. Four fulfill the above criteria: p.R61W; p.R75P; p.D80G; and p.R213K. Patients carrying these mutations had typical clinical CADASIL syndrome and diffuse white matter hyperintensities, mostly without anterior temporal pole involvement. Cysteine-sparing NOTCH3 missense mutations are associated with typical clinical CADASIL syndrome and typical magnetic resonance imaging (MRI findings, although with less involvement of the anterior temporal lobe. Hence, these mutations should be further studied to confirm their pathological role in CADASIL.

  18. Truncation and microdeletion of EVC/EVC2 with missense mutation of EFCAB7 in Ellis-van Creveld syndrome.

    Science.gov (United States)

    Nguyen, Tran Quynh Nhu; Saitoh, Makiko; Trinh, Huu Tung; Doan, Nguyen Minh Thien; Mizuno, Yoko; Seki, Masafumi; Sato, Yusuke; Ogawa, Seishi; Mizuguchi, Masashi

    2016-09-01

    Ellis-van Creveld syndrome (EvC) is a ciliopathy with cardiac anomalies, disproportionate short stature, polydactyly, dystrophic nails and oral defects. To obtain further insight into the genetics of EvC, we screened EVC/EVC2 mutations in eight Vietnamese EvC patients. All the patients had a congenital heart defect with atypical oral and/or skeletal abnormalities. One had compound heterozygous EVC2 mutations: a novel mutation c.769G > T-p.E177X in exon 6 inherited from father and another previously reported c.2476C > T-p.R826X mutation in exon 14 inherited from mother. The EVC2 mRNA expression level was significantly lower in the patient and her parents compared to controls. Another case had a novel heterozygous EVC mutation (c.1717C > G-p.S572X) in exon 12, inherited from his father. Of note, the mother without any EVC mutation on Sanger sequencing showed a lower expression level of EVC mRNA compared with controls. SNP array analysis revealed that the patient and mother had a heterozygous 16.4 kb deletion in EVC. This patient also had a heterozygous novel variant in exon 9 of EFCAB7 (c.1171 T > C-p.Y391H), inherited from his father. The atypical cardiac phenotype of this patient and the father suggested that EFCAB7 may modify the phenotype by interacting with EVC. In conclusion, we detected two novel nonsense mutations and a partial deletion of EVC/EVC2 in two Vietnamese families with EvC. Moreover, we found in one family a missense mutation of EFCAB7, a possible modifier gene in EvC and its related disorders.

  19. Novel splice, missense, and nonsense mutations in the fumarylacetoacetase gene causing tyrosinemia type I

    Energy Technology Data Exchange (ETDEWEB)

    Rootwelt, H.; Kvittingen, E.A. [Univ. of Oslo (Norway); Berger, R. [Wilhelmina Kinderziekenhuis, Utrecht (Netherlands); Gray, G.; Kelly, D.A. [Children`s Hospital, Birmingham (United Kingdom); Coskun, T. [Hacettepe Univ., Ankara (Turkey)

    1994-10-01

    In six unrelated patients with hereditary tyrosinemia type 1 (HT1), three different disease-causing mutations were found by DNA sequencing. Two Pakistani patients, with acute and intermediate forms of HT1, were homozygous for a G{sup 192} {yields} T mutation in the last nucleotide of exon 2. This caused aberrant splicing with partial intron 2 retention and premature termination. Three Turkish patients with chronic and intermediate forms of HT1 were homozygous for an A{sup 698} {yields} T mutation substituting aspartic acid 233 with valine. A Norwegian patient with an intermediate clinical phenotype was heterozygous for G{sup 786} {yields} A, introducing a TGA stop codon for Trp262 (W262X). Site-directed mutagenesis and expression in a rabbit reticulocyte lysate system demonstrated that the nonsense and missense mutations abolished fumarylacetoacetase activity and gave reduced amounts of a truncated and a full-length protein, respectively. Simple tests were established to identify the three mutations by restriction digestion of PCR-amplified genomic DNA. Among 30 additional HT1 patients investigated, 2 were found to be homozygous and 1 heterozygous for G{sup 192} {yields} T. Two other patients were homozygous and one was heterozygous for W262X. 21 refs., 4 figs.

  20. Heteroallelic missense mutations of the galactosamine-6-sulfate sulfatase (GALNS) gene in a mild form of Morquio disease (MPS IVA)

    Energy Technology Data Exchange (ETDEWEB)

    Cole, D.E.C. [Univ. of Toronto, Ontario (Canada); Gordon, B.A.; Rupar, C.A. [Univ. of Western Ontario, London (Canada)] [and others

    1996-06-28

    Morquio disease (MPS IVA) is an autosomal recessive disorder caused by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS) activity. Patients commonly present in early infancy with growth failure, spondyloepiphyseal dysplasia, corneal opacification, and keratan sulfaturia, but milder forms have been described. We report on a patient who grew normally until age 5 years. Her keratan sulfaturia was not detected until adolescence, and she now has changes restricted largely to the axial skeleton. She has experienced only mildly impaired vision. At age 22, thin-layer chromatography of purified glycosaminoglycans showed some keratan sulfaturia. GALNS activity in fibroblast homogenate supernatants was 20 {plus_minus} 5% of controls (as compared to 5 {plus_minus} 3% of controls in severe MPS IVA, P <.003). Kinetic analysis of residual fibroblast GALNS activity in patient and parents revealed decreased K{sub m} and increased V{sub max} in the mother and daughter, but not in the father, compatible with compound heterozygosity. GALNS exons were amplified from patient genomic DNA and screened by SSCP. Two missense mutations, a C to T transition at position 335 (predicting R94C) and a T to G transversion at position 344 (predicting F97V), were found on sequencing an abnormally migrating exon 3 amplicon. Digestion of the amplicon with FokI and AccI restriction enzymes (specific for the R94C and F97V mutations, respectively) confirmed heterozygosity. In fibroblast transfection experiments, heterozygous R94C and F97V mutants independently expressed as severe and mile GALNS deficiency, respectively. We interpret these findings to indicate that our patient bears heteroallelic GALNS missense mutations, leading to GALNS deficiency and mild MPS IVA. Our findings expand the clinical and biochemical phenotype of MPS IVA, but full delineation of the genotype-phenotype relationship requires further study of native and transfected mutant cell lines. 30 refs., 4 figs., 3 tabs.

  1. Structure-Function Correlation Analysis of Connexin50 Missense Mutations Causing Congenital Cataract: Electrostatic Potential Alteration Could Determine Intracellular Trafficking Fate of Mutants

    Directory of Open Access Journals (Sweden)

    Devroop Sarkar

    2014-01-01

    Full Text Available Connexin50 (Cx50 mutations are reported to cause congenital cataract probably through the disruption of intercellular transport in the lens. Cx50 mutants that undergo mistrafficking have generally been associated with failure to form functional gap junction channels; however, sometimes even properly trafficked mutants were found to undergo similar consequences. We hereby wanted to elucidate any structural bases of the varied functional consequences of Cx50 missense mutations through in silico approach. Computational studies have been done based on a Cx50 homology model to assess conservation, solvent accessibility, and 3-dimensional localization of mutated residues as well as mutation-induced changes in surface electrostatic potential, H-bonding, and steric clash. This was supplemented with meta-analysis of published literature on the functional properties of connexin missense mutations. Analyses revealed that the mutation-induced critical alterations of surface electrostatic potential in Cx50 mutants could determine their fate in intracellular trafficking. A similar pattern was observed in case of mutations involving corresponding conserved residues in other connexins also. Based on these results the trafficking fates of 10 uncharacterized Cx50 mutations have been predicted. Further experimental analyses are needed to validate the observed correlation.

  2. Homozygosity mapping approach identifies a missense mutation in equine cyclophilin B (PPIB) associated with HERDA in the American Quarter Horse.

    Science.gov (United States)

    Tryon, Robert C; White, Stephen D; Bannasch, Danika L

    2007-07-01

    Hereditary equine regional dermal asthenia (HERDA), a degenerative skin disease that affects the Quarter Horse breed, was localized to ECA1 by homozygosity mapping. Comparative genomics allowed the development of equine gene-specific markers which were used with a set of affected horses to detect a homozygous, identical-by-descent block spanning approximately 2.5 Mb, suggesting a recent origin for the HERDA mutation. We report a mutation in cyclophilin B (PPIB) as a novel, causal candidate gene for HERDA. A c.115G>A missense mutation in PPIB alters a glycine residue that has been conserved across vertebrates. The mutation was homozygous in 64 affected horses and segregates concordant with inbreeding loops apparent in the genealogy of 11 affected horses. Screening of control Quarter Horses indicates a 3.5% carrier frequency. The development of a test that can detect affected horses prior to development of clinical signs and carriers of HERDA will allow Quarter Horse breeders to eliminate this debilitating disease.

  3. The Pro115Gln Missense Mutation of Peroxisome Proliferator Activated Receptor γ (PPARγ Gene in Diabetes in the Pakistani Population

    Directory of Open Access Journals (Sweden)

    Sumbal

    2016-05-01

    Full Text Available Background Diabetes is an alarmingly increasing public health concern. According to a World Health Organization (WHO report, diabetes is highly prevalent in almost all regions of Pakistan, with an overall prevalence of 22.04% in urban and 17.15% in rural areas. In addition to lifestyle factors, genetics plays an important part in the progression to diabetes, of which peroxisome proliferator activated receptors (PPARs, a super-family of transcriptional regulators, are considered to be very critical. Objectives The aim of the current study was to investigate the prevalence of a missense mutation Pro115Gln in the PPARγ; gene in Pakistan and search for its effects on certain serum biochemical parameters. Materials and Methods A total of 1015 subjects (490 diabetics and 525 healthy controls were genotyped by PCR-RFLP and serum profiling was performed. Results We could not detect the mutation in the study subjects, but the anthropometric and biochemical parameters were significantly different between the cases and controls. Conclusions In conclusion, as this mutation is present in a highly conserved region and any change in this region would adversely affect the protein structure and function, so the prevalence of this mutation is very low.

  4. A missense mutation in Fgfr1 causes ear and skull defects in hush puppy mice.

    Science.gov (United States)

    Calvert, Jennifer A; Dedos, Skarlatos G; Hawker, Kelvin; Fleming, Michelle; Lewis, Morag A; Steel, Karen P

    2011-06-01

    The hush puppy mouse mutant has been shown previously to have skull and outer, middle, and inner ear defects, and an increase in hearing threshold. The fibroblast growth factor receptor 1 (Fgfr1) gene is located in the region of chromosome 8 containing the mutation. Sequencing of the gene in hush puppy heterozygotes revealed a missense mutation in the kinase domain of the protein (W691R). Homozygotes were found to die during development, at approximately embryonic day 8.5, and displayed a phenotype similar to null mutants. Reverse transcription PCR indicated a decrease in Fgfr1 transcript in heterozygotes and homozygotes. Generation of a construct containing the mutation allowed the function of the mutated receptor to be studied. Immunocytochemistry showed that the mutant receptor protein was present at the cell membrane, suggesting normal expression and trafficking. Measurements of changes in intracellular calcium concentration showed that the mutated receptor could not activate the IP(3) pathway, in contrast to the wild-type receptor, nor could it initiate activation of the Ras/MAP kinase pathway. Thus, the hush puppy mutation in fibroblast growth factor receptor 1 appears to cause a loss of receptor function. The mutant protein appears to have a dominant negative effect, which could be due to it dimerising with the wild-type protein and inhibiting its activity, thus further reducing the levels of functional protein. A dominant modifier, Mhspy, which reduces the effect of the hush puppy mutation on pinna and stapes development, has been mapped to the distal end of chromosome 7 and may show imprinting.

  5. Congenital insensitivity to pain: novel SCN9A missense and in-frame deletion mutations.

    Science.gov (United States)

    Cox, James J; Sheynin, Jony; Shorer, Zamir; Reimann, Frank; Nicholas, Adeline K; Zubovic, Lorena; Baralle, Marco; Wraige, Elizabeth; Manor, Esther; Levy, Jacov; Woods, C Geoffery; Parvari, Ruti

    2010-09-01

    SCN9Aencodes the voltage-gated sodium channel Na(v)1.7, a protein highly expressed in pain-sensing neurons. Mutations in SCN9A cause three human pain disorders: bi-allelic loss of function mutations result in Channelopathy-associated Insensitivity to Pain (CIP), whereas activating mutations cause severe episodic pain in Paroxysmal Extreme Pain Disorder (PEPD) and Primary Erythermalgia (PE). To date, all mutations in SCN9A that cause a complete inability to experience pain are protein truncating and presumably lead to no protein being produced. Here, we describe the identification and functional characterization of two novel non-truncating mutations in families with CIP: a homozygously-inherited missense mutation found in a consanguineous Israeli Bedouin family (Na(v)1.7-R896Q) and a five amino acid in-frame deletion found in a sporadic compound heterozygote (Na(v)1.7-DeltaR1370-L1374). Both of these mutations map to the pore region of the Na(v)1.7 sodium channel. Using transient transfection of PC12 cells we found a significant reduction in membrane localization of the mutant protein compared to the wild type. Furthermore, voltage clamp experiments of mutant-transfected HEK293 cells show a complete loss of function of the sodium channel, consistent with the absence of pain phenotype. In summary, this study has identified critical amino acids needed for the normal subcellular localization and function of Na(v)1.7.

  6. Isolated NIBPL missense mutations that cause Cornelia de Lange syndrome alter MAU2 interaction

    Science.gov (United States)

    Braunholz, Diana; Hullings, Melanie; Gil-Rodríguez, María Concepcion; Fincher, Christopher T; Mallozzi, Mark B; Loy, Elizabeth; Albrecht, Melanie; Kaur, Maninder; Limon, Janusz; Rampuria, Abhinav; Clark, Dinah; Kline, Antonie; Dalski, Andreas; Eckhold, Juliane; Tzschach, Andreas; Hennekam, Raoul; Gillessen-Kaesbach, Gabriele; Wierzba, Jolanta; Krantz, Ian D; Deardorff, Matthew A; Kaiser, Frank J

    2012-01-01

    Cornelia de Lange syndrome (CdLS; or Brachmann-de Lange syndrome) is a dominantly inherited congenital malformation disorder with features that include characteristic facies, cognitive delays, growth retardation and limb anomalies. Mutations in nearly 60% of CdLS patients have been identified in NIPBL, which encodes a regulator of the sister chromatid cohesion complex. NIPBL, also known as delangin, is a homolog of yeast and amphibian Scc2 and C. elegans PQN-85. Although the exact mechanism of NIPBL function in sister chromatid cohesion is unclear, in vivo yeast and C. elegans experiments and in vitro vertebrate cell experiments have demonstrated that NIPBL/Scc2 functionally interacts with the MAU2/Scc4 protein to initiate loading of cohesin onto chromatin. To test the significance of this model in the clinical setting of CdLS, we fine-mapped the NIBPL–MAU2 interaction domain and tested the functional significance of missense mutations and variants in NIPBL and MAU2 identified in these minimal domains in a cohort of patients with CdLS. We demonstrate that specific novel mutations at the N-terminus of the MAU2-interacting domain of NIBPL result in markedly reduced MAU2 binding, although we appreciate no consistent clinical difference in the small group of patients with these mutations. These data suggest that factors in addition to MAU2 are essential in determining the clinical features and severity of CdLS. PMID:21934712

  7. A Novel Missense Mutation in Oncostatin M Receptor Beta Causing Primary Localized Cutaneous Amyloidosis

    Directory of Open Access Journals (Sweden)

    Marjan Saeedi

    2014-01-01

    Full Text Available Primary localized cutaneous amyloidosis (PLCA is a chronic skin disorder, caused by amyloid material deposition in the upper dermis. Autosomal dominant PLCA has been mapped earlier to pathogenic missense mutations in the OSMR gene, which encodes the oncostatin M receptor ß subunit (OSMRß. OSMRß is interleukin-6 family cytokine receptors and possesses two ligands, oncostatin M and interleukin-31, which both have biologic roles in inflammation and keratinocyte cell proliferation, differentiation, and apoptosis. Here, we identified a new OSMR mutation in a Kurdish family for the first time. Blood samples were taken from all the affected individuals in the family. DNA extraction was performed using salting out technique. Primers were designed for intron flanking individual exons of OSMR gene which were subjected to direct sequencing after PCR amplification for each sample. Sequencing showed a C/T substitution at position 613 in the proband. This mutation results in an L613S (leucine 613 to serine amino acid change. The identified mutation was observed in all affected family members but not in 100 ethnically matched healthy controls. Elucidating the molecular basis of familial PLCA provides new insight into mechanisms of itch in human skin and may lead to new therapeutic targets for pruritus.

  8. A missense mutation in the 3-ketodihydrosphingosine reductase FVT1 as candidate causal mutation for bovine spinal muscular atrophy.

    Science.gov (United States)

    Krebs, Stefan; Medugorac, Ivica; Röther, Susanne; Strässer, Katja; Förster, Martin

    2007-04-17

    The bovine form of the autosomal recessive neurodegenerative disease spinal muscular atrophy (SMA) shows striking similarity to the human form of the disease. It has, however, been mapped to a genomic region not harboring the bovine orthologue of the SMN gene, mutation of which causes human SMA. After refinement of the mapping results we analyzed positional and functional candidate genes. One of three candidate genes, FVT1, encoding 3-ketodihydrosphingosine reductase, which catalyzes a crucial step in the glycosphingolipid metabolism, showed a G-to-A missense mutation that changes Ala-175 to Thr. The identified mutation is limited to SMA-affected animals and carriers and always appears in context of the founder haplotype. The Ala variant found in healthy animals showed the expected 3-ketodihydrosphingosine reductase activity in an in vitro enzyme assay. Importantly, the Thr variant found in SMA animals showed no detectable activity. Surprisingly, in an in vivo assay the mutated gene complements the growth defect of a homologous yeast knockout strain as well as the healthy variant. This finding explains the viability of affected newborn calves and the later neuron-specific onset of the disease, which might be due to the high sensitivity of these neurons to changes in housekeeping functions. Taken together, the described mutation in FVT1 is a strong candidate for causality of SMA in cattle. This result provides an animal model for understanding the underlying mechanisms of the development of SMA and will allow efficient selection against the disease in cattle.

  9. A missense mutation in zbtb17 blocks the earliest steps of T cell differentiation in zebrafish

    Science.gov (United States)

    Lawir, Divine-Fondzenyuy; Iwanami, Norimasa; Schorpp, Michael; Boehm, Thomas

    2017-01-01

    T cells are an evolutionarily conserved feature of the adaptive immune systems of vertebrates. Comparative studies using evolutionarily distant species hold great promise for unraveling the genetic landscape underlying this process. To this end, we used ENU mutagenesis to generate mutant zebrafish with specific aberrations in early T cell development. Here, we describe the identification of a recessive missense mutation in the transcriptional regulator zbtb17 (Q562K), which affects the ninth zinc finger module of the protein. Homozygous mutant fish exhibit an early block of intrathymic T cell development, as a result of impaired thymus colonization owing to reduced expression of the gene encoding the homing receptor ccr9a, and inefficient T cell differentiation owing to reduced expression of socs1a. Our results reveal the zbtb17-socs1 axis as an evolutionarily conserved central regulatory module of early T cell development of vertebrates. PMID:28266617

  10. RYR2 sequencing reveals novel missense mutations in a Kazakh idiopathic ventricular tachycardia study cohort.

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    Ainur Akilzhanova

    Full Text Available Channelopathies, caused by disturbed potassium or calcium ion management in cardiac myocytes are a major cause of heart failure and sudden cardiac death worldwide. The human ryanodine receptor 2 (RYR2 is one of the key players tightly regulating calcium efflux from the sarcoplasmic reticulum to the cytosol and found frequently mutated (T; p.D4631V in a CPVT patient and a novel rare variant (c5428G>C; p.V1810L of uncertain significance in a patient with VT of idiopathic origin which we suggest represents a low-penetrance or susceptibility variant. In addition we identified a known variant previously associated with arrhythmogenic right ventricular dysplasia type2 (ARVD2. Combining sets of prediction scores and reference databases appeared fundamental to predict the pathogenic potential of novel and rare missense variants in populations where genotype data are rare.

  11. Prevalence of the Pro12Ala missense mutation in the PPARG2 gene in Kuwaiti patients with primary knee osteoarthritis.

    Science.gov (United States)

    Al-Jarallah, Khaled F; Shehab, Diaa K; Haider, Mohammad Z

    2011-01-01

    Peroxisome proliferator-activated receptors (PPARs) play an important role in a number of cellular and metabolic functions. This study was carried out to determine the prevalence of a missense mutation (Pro12Ala) in the PPARG2 gene in Kuwaiti Arab patients with primary knee osteoarthritis (OA) and healthy controls with the aim of identifying a possible association. A prospective cross-sectional study carried out at three major teaching hospitals (referral centers) in the country over a one-year period. The prevalence of PPARG2 gene Pro12Ala missense mutation was determined in 104 Kuwaiti Arab patients with primary knee OA and 111 ethnically matched healthy controls. The prevalence of this Pro12Ala missense mutation was also determined in clinical subgroups of OA patients divided on the basis of age at onset, function and radiologic grading. The Pro-Pro genotype of the PPARG2 gene Pro12Ala missense mutation was detected in 95/104 (91.3%) cases compared to 111/111 (100%) in the control subjects. The heterozygous Pro-Ala genotype was detected in 9/104 (8.7%) of the OA patients, while it was not detected in any of the controls. The Ala-Ala genotype was not detected in any of the OA patients or the controls. No significant differences were detected in the PPARG2 gene Pro12Ala genotypes in the subgroups of patients classified on the basis of age at onset, functional assessment using Lequesne's functional index, and radiological grading using Kellgren-Lawrence (K-L) grading. This study found no significant association between the PPARG2 gene Pro12Ala missense mutation and knee OA. However, the presence of the Pro-Pro genotype of the PPARG2 gene mutation has a protective effect against development of OA.

  12. Characterization of a novel missense mutation on murine Pax3 through ENU mutagenesis

    Institute of Scientific and Technical Information of China (English)

    Yue Xiao; Lingling Zhang; Kuanjun He; Xiang Gao; Lun Yang; Lin He; Gang Ma

    2011-01-01

    N-ethyl-N-nitrosourea (ENU) mutagenesis has led to the elucidation of several regulator genes for melanocyte and skin development.Here we characterized a mutant from ENU mutagenesis with similar phenotype as that of Splotch mutant,including exencephaly,spina bifida and abnormal limbs in homozygotes as well as white belly spotting and occasionally loop-tail in heterozygotes.This novel mutant was named as SpxG..Through genome-wide linkage analysis in backcross progenies with microsatellite markers,the SpxG was confined to a region between D1MIT415 and D1M IT7 on chromosome 1,where notable Pax3 gene was located.Direct sequencing revealed that SpxG carried a nucleotide A894G missense transition in exon 6 of Pax3 gene that resulted in Asn to Asp substitution at amino acid 269 within the highly-conserved homeodomain (HD) DNA recognition module,which was the first point mutation found in this domain in mice.This N269D mutation impaired the transactivation capacity of Pax3 protein,but exerted no effect on Pax3 protein translation.The characterization of the new mutation expanded our understanding the transactivation and DNA-binding structure of Pax3 protein.

  13. [Primary hypoaldosteronism and moderate bilateral deafness in a child with a homozygous missense mutation (Thr318Met) in the CYP11B2 gene].

    Science.gov (United States)

    Rubio-Cabezas, O; Regueras, L; Muñoz-Calvo, M T; Bartolomé, M; Pozo, J; Argente, J

    2010-07-01

    Isolated congenital hypoaldosteronism is a rare disorder that presents as chronic salt-wasting syndrome during infancy. Aldosterone synthase deficiency due to mutations in CYP11B2 is the underlying cause in most cases. Apart from the classical electrolyte disturbances (hyponatremia and hyperkalemia), no other extra-adrenal features have been described to date. We report a male child with congenital hypoaldosteronism due to a homozygous missense mutation (Thr318Met) in CYP11B2 who also presented with unexplained sensorineural hearing loss.

  14. Benchmarking mutation effect prediction algorithms using functionally validated cancer-related missense mutations.

    Science.gov (United States)

    Martelotto, Luciano G; Ng, Charlotte Ky; De Filippo, Maria R; Zhang, Yan; Piscuoglio, Salvatore; Lim, Raymond S; Shen, Ronglai; Norton, Larry; Reis-Filho, Jorge S; Weigelt, Britta

    2014-10-28

    Massively parallel sequencing studies have led to the identification of a large number of mutations present in a minority of cancers of a given site. Hence, methods to identify the likely pathogenic mutations that are worth exploring experimentally and clinically are required. We sought to compare the performance of 15 mutation effect prediction algorithms and their agreement. As a hypothesis-generating aim, we sought to define whether combinations of prediction algorithms would improve the functional effect predictions of specific mutations. Literature and database mining of single nucleotide variants (SNVs) affecting 15 cancer genes was performed to identify mutations supported by functional evidence or hereditary disease association to be classified either as non-neutral (n = 849) or neutral (n = 140) with respect to their impact on protein function. These SNVs were employed to test the performance of 15 mutation effect prediction algorithms. The accuracy of the prediction algorithms varies considerably. Although all algorithms perform consistently well in terms of positive predictive value, their negative predictive value varies substantially. Cancer-specific mutation effect predictors display no-to-almost perfect agreement in their predictions of these SNVs, whereas the non-cancer-specific predictors showed no-to-moderate agreement. Combinations of predictors modestly improve accuracy and significantly improve negative predictive values. The information provided by mutation effect predictors is not equivalent. No algorithm is able to predict sufficiently accurately SNVs that should be taken forward for experimental or clinical testing. Combining algorithms aggregates orthogonal information and may result in improvements in the negative predictive value of mutation effect predictions.

  15. Gene co-expression analyses differentiate networks associated with diverse cancers harbouring TP53 missense or null mutations

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    Kathleen Oros Klein

    2016-08-01

    Full Text Available In a variety of solid cancers, missense mutations in the well-established TP53 tumour suppressor gene may lead to presence of a partially-functioning protein molecule, whereas mutations affecting the protein encoding reading frame, often referred to as null mutations, result in the absence of p53 protein. Both types of mutations have been observed in the same cancer type. As the resulting tumour biology may be quite different between these two groups, we used RNA-sequencing data from The Cancer Genome Atlas (TCGA from four different cancers with poor prognosis, namely ovarian, breast, lung and skin cancers, to compare the patterns of co-expression of genes in tumours grouped according to their TP53 missense or null mutation status. We used Weighted Gene Coexpression Network analysis (WGCNA and a new test statistic built on differences between groups in the measures of gene connectivity. For each cancer, our analysis identified a set of genes showing differential coexpression patterns between the TP53 missense- and null mutation-carrying groups that was robust to the choice of the tuning parameter in WGCNA. After comparing these sets of genes across the four cancers, one gene (KIR3DL2 consistently showed differential coexpression patterns between the null and missense groups. KIR3DL2 is known to play an important role in regulating the immune response, which is consistent with our observation that this gene’s strongly-correlated partners implicated many immune-related pathways. Examining mutation-type-related changes in correlations between sets of genes may provide new insight into tumour biology.

  16. Non-syndromic tooth agenesis in two Chinese families associated with novel missense mutations in the TNF domain of EDA (ectodysplasin A.

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    Shufeng Li

    Full Text Available Here we report two unrelated Chinese families with congenital missing teeth inherited in an X-linked manner. We mapped the affected locus to chromosome Xp11-Xq21 in one family. In the defined region, both families were found to have novel missense mutations in the ectodysplasin-A (EDA gene. The mutation of c.947A>G caused the D316G substitution of the EDA protein. The mutation of c.1013C>T found in the other family resulted in the Thr to Met mutation at position 338 of EDA. The EDA gene has been reported responsible for X-linked hypohidrotic ectodermal dysplasia (XLHED in humans characterized by impaired development of hair, eccrine sweat glands, and teeth. In contrast, all the affected individuals in the two families that we studied here had normal hair and skin. Structural analysis suggests that these two novel mutants may account for the milder phenotype by affecting the stability of EDA trimers. Our results indicate that these novel missense mutations in EDA are associated with the isolated tooth agenesis and provide preliminary explanation for the abnormal clinical phenotype at a molecular structural level.

  17. A missense mutation in ITGB6 causes pitted hypomineralized amelogenesis imperfecta.

    Science.gov (United States)

    Poulter, James A; Brookes, Steven J; Shore, Roger C; Smith, Claire E L; Abi Farraj, Layal; Kirkham, Jennifer; Inglehearn, Chris F; Mighell, Alan J

    2014-04-15

    We identified a family in which pitted hypomineralized amelogenesis imperfecta (AI) with premature enamel failure segregated in an autosomal recessive fashion. Whole-exome sequencing revealed a missense mutation (c.586C>A, p.P196T) in the I-domain of integrin-β6 (ITGB6), which is consistently predicted to be pathogenic by all available programmes and is the only variant that segregates with the disease phenotype. Furthermore, a recent study revealed that mice lacking a functional allele of Itgb6 display a hypomaturation AI phenotype. Phenotypic characterization of affected human teeth in this study showed areas of abnormal prismatic organization, areas of low mineral density and severe abnormal surface pitting in the tooth's coronal portion. We suggest that the pathogenesis of this form of AI may be due to ineffective ligand binding of ITGB6 resulting in either compromised cell-matrix interaction or compromised ITGB6 activation of transforming growth factor-β (TGF-β) impacting indirectly on ameloblast-ameloblast interactions and proteolytic processing of extracellular matrix proteins via MMP20. This study adds to the list of genes mutated in AI and further highlights the importance of cell-matrix interactions during enamel formation.

  18. A Novel Missense Mutation in the CLPP Gene Causing Perrault Syndrome Type 3 in a Turkish Family

    Science.gov (United States)

    Dursun, Fatma; Mohamoud, Hussein Sheikh Ali; Karim, Noreen; Naeem, Muhammad; Jelani, Musharraf; Kırmızıbekmez, Heves

    2016-01-01

    Perrault syndrome (PRLTS) is a heterogeneous group of clinical and genetic disorders characterized by sensory neuronal hearing loss in both sexes and premature ovarian failure or infertility in females. Neurological and hearing loss symptoms appear early in life, but female infertility cannot be detected before puberty. Spastic limbs, muscle weakness, delayed puberty and irregular menstrual cycles have also been observed in PRLTS patients. Mutations in five genes, i.e. HSD17B4, HARS2, CLPP, LARS2, and C10orf2, have been reported in five subtypes of PRLTS. Here, we report a milder phenotype of PRLTS in a Turkish family in which two affected patients had no neurological findings. However, both were characterized by sensory neuronal hearing loss and the female sibling had secondary amenorrhea and gonadal dysgenesis. Genome-wide homozygosity mapping using 300K single-nucleotide polymorphism microarray analysis together with iScan platform (Illumina, USA) followed by candidate gene Sanger sequencing with ABI 3500 Genetic Analyzer (Life Technologies, USA) were used for molecular diagnosis. We found a novel missense alteration c.624C>G; p.Ile208Met in exon 5 of the CLPP at chromosome 19p13.3. This study expands the mutation spectrum of CLPP pathogenicity in PRLTS type 3 phenotype. PMID:27087618

  19. In silico calculated affinity of FVIII-derived peptides for HLA class II alleles predicts inhibitor development in haemophilia A patients with missense mutations in the F8 gene.

    Science.gov (United States)

    Pashov, A D; Calvez, T; Gilardin, L; Maillère, B; Repessé, Y; Oldenburg, J; Pavlova, A; Kaveri, S V; Lacroix-Desmazes, S

    2014-03-01

    Forty per cent of haemophilia A (HA) patients have missense mutations in the F8 gene. Yet, all patients with identical mutations are not at the same risk of developing factor VIII (FVIII) inhibitors. In severe HA patients, human leucocyte antigen (HLA) haplotype was identified as a risk factor for onset of FVIII inhibitors. We hypothesized that missense mutations in endogenous FVIII alter the affinity of the mutated peptides for HLA class II, thus skewing FVIII-specific T-cell tolerance and increasing the risk that the corresponding wild-type FVIII-derived peptides induce an anti-FVIII immune response during replacement therapy. Here, we investigated whether affinity for HLA class II of wild-type FVIII-derived peptides that correspond to missense mutations described in the Haemophilia A Mutation, Structure, Test and Resource database is associated with inhibitor development. We predicted the mean affinity for 10 major HLA class II alleles of wild-type FVIII-derived peptides that corresponded to 1456 reported cases of missense mutations. Linear regression analysis confirmed a significant association between the predicted mean peptide affinity and the mutation inhibitory status (P = 0.006). Significance was lost after adjustment on mutation position on FVIII domains. Although analysis of the A1-A2-A3-C1 domains yielded a positive correlation between predicted HLA-binding affinity and inhibitory status (OR = 0.29 [95% CI: 0.14-0.60] for the high affinity tertile, P = 0.002), the C2 domain-restricted analysis indicated an inverse correlation (OR = 3.56 [1.10-11.52], P = 0.03). Our data validate the importance of the affinity of FVIII peptides for HLA alleles to the immunogenicity of therapeutic FVIII in patients with missense mutations. © 2013 John Wiley & Sons Ltd.

  20. A novel heterozygous missense mutation in the UMOD gene responsible for Familial Juvenile Hyperuricemic Nephropathy

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    Clemente Carla

    2005-01-01

    Full Text Available Abstract Background Familial Juvenile Hyperuricemic Nephropathy is an autosomal dominant nephropathy, characterized by decreased urate excretion and progressive interstitial nephritis. Mutations in the uromodulin coding UMOD gene have been found responsible for the disease in some families. Case presentation We here describe a novel heterozygous p.K307T mutation in an affected female with hyperuricemia, renal cysts and renal failure. The proband's only son is also affected and the mutation was found to segregate with the disease. Conclusions This mutation is the fourth reported in exon 5. Initial studies identified a mutation clustering in exon 4 and it has been recommended that sequencing this exon alone should be the first diagnostic test in patients with chronic interstitial nephritis with gout or hyperuricemia. However, regarding the increasing number of mutations being reported in exon 5, we now suggest that sequencing exon 5 should also be performed.

  1. High Incidence of Noonan Syndrome Features Including Short Stature and Pulmonic Stenosis in Patients carrying NF1 Missense Mutations Affecting p.Arg1809: Genotype-Phenotype Correlation.

    Science.gov (United States)

    Rojnueangnit, Kitiwan; Xie, Jing; Gomes, Alicia; Sharp, Angela; Callens, Tom; Chen, Yunjia; Liu, Ying; Cochran, Meagan; Abbott, Mary-Alice; Atkin, Joan; Babovic-Vuksanovic, Dusica; Barnett, Christopher P; Crenshaw, Melissa; Bartholomew, Dennis W; Basel, Lina; Bellus, Gary; Ben-Shachar, Shay; Bialer, Martin G; Bick, David; Blumberg, Bruce; Cortes, Fanny; David, Karen L; Destree, Anne; Duat-Rodriguez, Anna; Earl, Dawn; Escobar, Luis; Eswara, Marthanda; Ezquieta, Begona; Frayling, Ian M; Frydman, Moshe; Gardner, Kathy; Gripp, Karen W; Hernández-Chico, Concepcion; Heyrman, Kurt; Ibrahim, Jennifer; Janssens, Sandra; Keena, Beth A; Llano-Rivas, Isabel; Leppig, Kathy; McDonald, Marie; Misra, Vinod K; Mulbury, Jennifer; Narayanan, Vinodh; Orenstein, Naama; Galvin-Parton, Patricia; Pedro, Helio; Pivnick, Eniko K; Powell, Cynthia M; Randolph, Linda; Raskin, Salmo; Rosell, Jordi; Rubin, Karol; Seashore, Margretta; Schaaf, Christian P; Scheuerle, Angela; Schultz, Meredith; Schorry, Elizabeth; Schnur, Rhonda; Siqveland, Elizabeth; Tkachuk, Amanda; Tonsgard, James; Upadhyaya, Meena; Verma, Ishwar C; Wallace, Stephanie; Williams, Charles; Zackai, Elaine; Zonana, Jonathan; Lazaro, Conxi; Claes, Kathleen; Korf, Bruce; Martin, Yolanda; Legius, Eric; Messiaen, Ludwine

    2015-11-01

    Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype-phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple café-au-lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan-like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P NF1-patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi-exon deletion, providing genetic evidence that p.Arg1809Cys is a loss-of-function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype-phenotype correlation will affect counseling and management of a significant number of patients.

  2. A novel missense mutation in ADAMTS10 in Norwegian Elkhound primary glaucoma.

    Science.gov (United States)

    Ahonen, Saija J; Kaukonen, Maria; Nussdorfer, Forrest D; Harman, Christine D; Komáromy, András M; Lohi, Hannes

    2014-01-01

    Primary glaucoma is one of the most common causes of irreversible blindness both in humans and in dogs. Glaucoma is an optic neuropathy affecting the retinal ganglion cells and optic nerve, and elevated intraocular pressure is commonly associated with the disease. Glaucoma is broadly classified into primary open angle (POAG), primary closed angle (PCAG) and primary congenital glaucoma (PCG). Human glaucomas are genetically heterogeneous and multiple loci have been identified. Glaucoma affects several dog breeds but only three loci and one gene have been implicated so far. We have investigated the genetics of primary glaucoma in the Norwegian Elkhound (NE). We established a small pedigree around the affected NEs collected from Finland, US and UK and performed a genome-wide association study with 9 cases and 8 controls to map the glaucoma gene to 750 kb region on canine chromosome 20 (praw = 4.93×10-6, pgenome = 0.025). The associated region contains a previously identified glaucoma gene, ADAMTS10, which was subjected to mutation screening in the coding regions. A fully segregating missense mutation (p.A387T) in exon 9 was found in 14 cases and 572 unaffected NEs (pFisher = 3.5×10-27) with a high carrier frequency (25.3%). The mutation interrupts a highly conserved residue in the metalloprotease domain of ADAMTS10, likely affecting its functional capacity. Our study identifies the genetic cause of primary glaucoma in NEs and enables the development of a genetic test for breeding purposes. This study establishes also a new spontaneous canine model for glaucoma research to study the ADAMTS10 biology in optical neuropathy.

  3. A novel missense mutation in ADAMTS10 in Norwegian Elkhound primary glaucoma.

    Directory of Open Access Journals (Sweden)

    Saija J Ahonen

    Full Text Available Primary glaucoma is one of the most common causes of irreversible blindness both in humans and in dogs. Glaucoma is an optic neuropathy affecting the retinal ganglion cells and optic nerve, and elevated intraocular pressure is commonly associated with the disease. Glaucoma is broadly classified into primary open angle (POAG, primary closed angle (PCAG and primary congenital glaucoma (PCG. Human glaucomas are genetically heterogeneous and multiple loci have been identified. Glaucoma affects several dog breeds but only three loci and one gene have been implicated so far. We have investigated the genetics of primary glaucoma in the Norwegian Elkhound (NE. We established a small pedigree around the affected NEs collected from Finland, US and UK and performed a genome-wide association study with 9 cases and 8 controls to map the glaucoma gene to 750 kb region on canine chromosome 20 (praw = 4.93×10-6, pgenome = 0.025. The associated region contains a previously identified glaucoma gene, ADAMTS10, which was subjected to mutation screening in the coding regions. A fully segregating missense mutation (p.A387T in exon 9 was found in 14 cases and 572 unaffected NEs (pFisher = 3.5×10-27 with a high carrier frequency (25.3%. The mutation interrupts a highly conserved residue in the metalloprotease domain of ADAMTS10, likely affecting its functional capacity. Our study identifies the genetic cause of primary glaucoma in NEs and enables the development of a genetic test for breeding purposes. This study establishes also a new spontaneous canine model for glaucoma research to study the ADAMTS10 biology in optical neuropathy.

  4. Mice with missense and nonsense NF1 mutations display divergent phenotypes compared with human neurofibromatosis type I.

    Science.gov (United States)

    Li, Kairong; Turner, Ashley N; Chen, Min; Brosius, Stephanie N; Schoeb, Trenton R; Messiaen, Ludwine M; Bedwell, David M; Zinn, Kurt R; Anastasaki, Corina; Gutmann, David H; Korf, Bruce R; Kesterson, Robert A

    2016-07-01

    Neurofibromatosis type 1 (NF1) is a common genetic disorder characterized by the occurrence of nerve sheath tumors and considerable clinical heterogeneity. Some translational studies have been limited by the lack of animal models available for assessing patient-specific mutations. In order to test therapeutic approaches that might restore function to the mutated gene or gene product, we developed mice harboring NF1 patient-specific mutations including a nonsense mutation (c.2041C>T; p.Arg681*) and a missense mutation (c.2542G>C; p.Gly848Arg). The latter is associated with the development of multiple plexiform neurofibromas along spinal nerve roots. We demonstrate that the human nonsense NF1(Arg681*) and missense NF1(Gly848Arg) mutations have different effects on neurofibromin expression in the mouse and each recapitulates unique aspects of the NF1 phenotype, depending upon the genetic context when assessed in the homozygous state or when paired with a conditional knockout allele. Whereas the missense Nf1(Gly848Arg) mutation fails to produce an overt phenotype in the mouse, animals homozygous for the nonsense Nf1(Arg681*) mutation are not viable. Mice with one Nf1(Arg681*) allele in combination with a conditional floxed Nf1 allele and the DhhCre transgene (Nf1(4F/Arg681*); DhhCre) display disorganized nonmyelinating axons and neurofibromas along the spinal column, which leads to compression of the spinal cord and paralysis. This model will be valuable for preclinical testing of novel nonsense suppression therapies using drugs to target in-frame point mutations that create premature termination codons in individuals with NF1.

  5. Mice with missense and nonsense NF1 mutations display divergent phenotypes compared with human neurofibromatosis type I

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    Kairong Li

    2016-07-01

    Full Text Available Neurofibromatosis type 1 (NF1 is a common genetic disorder characterized by the occurrence of nerve sheath tumors and considerable clinical heterogeneity. Some translational studies have been limited by the lack of animal models available for assessing patient-specific mutations. In order to test therapeutic approaches that might restore function to the mutated gene or gene product, we developed mice harboring NF1 patient-specific mutations including a nonsense mutation (c.2041C>T; p.Arg681* and a missense mutation (c.2542G>C; p.Gly848Arg. The latter is associated with the development of multiple plexiform neurofibromas along spinal nerve roots. We demonstrate that the human nonsense NF1Arg681* and missense NF1Gly848Arg mutations have different effects on neurofibromin expression in the mouse and each recapitulates unique aspects of the NF1 phenotype, depending upon the genetic context when assessed in the homozygous state or when paired with a conditional knockout allele. Whereas the missense Nf1Gly848Arg mutation fails to produce an overt phenotype in the mouse, animals homozygous for the nonsense Nf1Arg681* mutation are not viable. Mice with one Nf1Arg681* allele in combination with a conditional floxed Nf1 allele and the DhhCre transgene (Nf14F/Arg681*; DhhCre display disorganized nonmyelinating axons and neurofibromas along the spinal column, which leads to compression of the spinal cord and paralysis. This model will be valuable for preclinical testing of novel nonsense suppression therapies using drugs to target in-frame point mutations that create premature termination codons in individuals with NF1.

  6. Missense mutations in SLC26A8, encoding a sperm-specific activator of CFTR, are associated with human asthenozoospermia.

    Science.gov (United States)

    Dirami, Thassadite; Rode, Baptiste; Jollivet, Mathilde; Da Silva, Nathalie; Escalier, Denise; Gaitch, Natacha; Norez, Caroline; Tuffery, Pierre; Wolf, Jean-Philippe; Becq, Frédéric; Ray, Pierre F; Dulioust, Emmanuel; Gacon, Gérard; Bienvenu, Thierry; Touré, Aminata

    2013-05-02

    The cystic fibrosis transmembrane conductance regulator (CFTR) is present in mature sperm and is required for sperm motility and capacitation. Both these processes are controlled by ions fluxes and are essential for fertilization. We have shown that SLC26A8, a sperm-specific member of the SLC26 family of anion exchangers, associates with the CFTR channel and strongly stimulates its activity. This suggests that the two proteins cooperate to regulate the anion fluxes required for correct sperm motility and capacitation. Here, we report on three heterozygous SLC26A8 missense mutations identified in a cohort of 146 men presenting with asthenozoospermia: c.260G>A (p.Arg87Gln), c.2434G>A (p.Glu812Lys), and c.2860C>T (p.Arg954Cys). These mutations were not present in 121 controls matched for ethnicity, and statistical analysis on a control population of 8,600 individuals (from dbSNP and 1000 Genomes) showed them to be associated with asthenozoospermia with a power > 95%. By cotransfecting Chinese hamster ovary (CHO)-K1 cells with SLC26A8 variants and CFTR, we showed that the physical interaction between the two proteins was partly conserved but that the capacity to activate CFTR-dependent anion transport was completely abolished for all mutants. Biochemical studies revealed the presence of much smaller amounts of protein for all variants, but these amounts were restored to wild-type levels upon treatment with the proteasome inhibitor MG132. Immunocytochemistry also showed the amounts of SLC26A8 in sperm to be abnormally small in individuals carrying the mutations. These mutations might therefore impair formation of the SLC26A8-CFTR complex, principally by affecting SLC26A8 stability, consistent with an impairment of CFTR-dependent sperm-activation events in affected individuals.

  7. The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis.

    Science.gov (United States)

    Maheshwar, M M; Cheadle, J P; Jones, A C; Myring, J; Fryer, A E; Harris, P C; Sampson, J R

    1997-10-01

    Tuberous sclerosis is an autosomal dominant trait in which the dysregulation of cellular proliferation and differentiation results in the development of hamartomatous growths in many organs. The TSC2 gene is one of two genes determining tuberous sclerosis. Inactivating germline mutations of TSC2 in patients with tuberous sclerosis and somatic loss of heterozygosity at the TSC2 locus in the associated hamartomas indicate that TSC2 functions as a tumour suppressor gene and that loss of function is critical to expression of the tuberous sclerosis phenotype. The TSC2 product, tuberin, has a region of homology with the GTPase activating protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in vitro. Here we show that the region of homology between tuberin and human rap1GAP and the murine GAP mSpa1 is more extensive than previously reported and spans approximately 160 amino acid residues encoded within exons 34-38 of the TSC2 gene. Single strand conformation polymorphism analysis of these exons in 173 unrelated patients with tuberous sclerosis and direct sequencing of variant conformers together with study of additional family members enabled characterisation of disease associated mutations in 14 cases. Missense mutations, which occurred in exons 36, 37 and 38 were identified in eight cases, four of whom shared the same recurrent change P1675L. Each of the five different missense mutations identified was shown to occur de novo in at least one sporadic case of tuberous sclerosis. The high proportion of missense mutations detected in the region of the TSC2 gene encoding the GAP-related domain supports its key role in the regulation of cellular growth.

  8. A novel missense mutation (P366T) of the LHX4 gene causes severe combined pituitary hormone deficiency with pituitary hypoplasia, ectopic posterior lobe and a poorly developed sella turcica.

    Science.gov (United States)

    Tajima, Toshihiro; Hattori, Tsukasa; Nakajima, Takeo; Okuhara, Koji; Tsubaki, Junko; Fujieda, Kenji

    2007-08-01

    LIM homeodomain transcription factors regulate many aspects of development in multicellular organisms. LHX4/Lhx4 is a protein that is essential for pituitary development and motor neuron specification in mammals. In human, a heterozygous splicing mutation of the LHX4 gene was reported in a family with combined pituitary hormone deficiencies (CPHD). In addition to CPHD, these patients were characterized by small sella turcica and chiari malformation. Here we report a Japanese patient with CPHD (GH, PRL, TSH, LH, FSH, and ACTH deficiency) due to a novel missense mutation (P366T) of the LHX 4 gene. She showed severe respiratory disease and hypoglycemia soon after birth. Brain MRI demonstrated hypoplastic anterior pituitary, ectopic posterior lobe, a poorly developed sella turcica, and chiari malformation. Sequence analysis of the LHX 4 gene identified a heterozygous missense mutation (P366T) in exon 6, which was present in LIM4 specific domain. Neither of the patient's parents harbored this mutation, indicating de novo mutation.

  9. A missense mutation in melanocortin 1 receptor is associated with the red coat colour in donkeys.

    Science.gov (United States)

    Abitbol, M; Legrand, R; Tiret, L

    2014-12-01

    The seven donkey breeds recognised by the French studbook are characterised by few coat colours: black, bay and grey. Normand bay donkeys seldom give birth to red foals, a colour more commonly seen and recognised in American miniature donkeys. Red resembles the equine chestnut colour, previously attributed to a mutation in the melanocortin 1 receptor gene (MC1R). We used a panel of 124 donkeys to identify a recessive missense c.629T>C variant in MC1R that showed a perfect association with the red coat colour. This variant leads to a methionine to threonine substitution at position 210 in the protein. We showed that methionine 210 is highly conserved among vertebrate melanocortin receptors. Previous in silico and in vitro analyses predicted this residue to lie within a functional site. Our in vivo results emphasised the pivotal role played by this residue, the alteration of which yielded a phenotype fully compatible with a loss of function of MC1R. We thus propose to name the c.629T>C allele in donkeys the e allele, which further enlarges the panel of recessive MC1R loss-of-function alleles described in animals and humans.

  10. A missense mutation in DUSP6 is associated with Class III malocclusion.

    Science.gov (United States)

    Nikopensius, T; Saag, M; Jagomägi, T; Annilo, T; Kals, M; Kivistik, P A; Milani, L; Metspalu, A

    2013-10-01

    Class III malocclusion is a common dentofacial phenotype with a variable prevalence according to ethnic background. The etiology of Class III malocclusion has been attributed mainly to interactions between susceptibility genes and environmental factors during the morphogenesis of the mandible and maxilla. Class III malocclusion shows familial recurrence, and family-based studies support a predominance of an autosomal-dominant mode of inheritance. We performed whole-exome sequencing on five siblings from an Estonian family affected by Class III malocclusion. We identified a rare heterozygous missense mutation, c.545C>T (p.Ser182Phe), in the DUSP6 gene, a likely causal variant. This variant co-segregated with the disease following an autosomal-dominant mode of inheritance with incomplete penetrance. Transcriptional activation of DUSP6 has been presumed to be regulated by FGF/FGFR and MAPK/ERK signaling during fundamental processes at early stages of skeletal development. Several candidate genes within a linkage region on chromosome 12q22-q23--harboring DUSP6--are implicated in the regulation of maxillary or mandibular growth. The current study reinforces that the 12q22-q23 region is biologically relevant to craniofacial development and may be genetically linked to the Class III malocclusion.

  11. Absence of missense mutations in activated c-myc genes in avian leukosis virus-induced B-cell lymphomas

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, M.; Hayward, W.S.

    1988-06-01

    The authors determined the nucleotide sequences of two independent DNA clones which contained the activated c-myc genes from avian leukosis virus-induced B-cell lymphomas. Neither of these c-myce genes contained missense mutations. This strongly supports the notion that the c-myc photo-oncogene in avian leukosis virus-induced B-cell lymphomas can be oncogenically activated by altered expression of the gene without a change in the primary structure of the gene product.

  12. Identification of a novel missense mutation of MIP in a Chinese family with congenital cataracts by target region capture sequencing

    OpenAIRE

    Jiang,Bo; chen, Yanhua; Baisheng XU; Hong, Nan; Liu, Rongrong; Qi, Ming; Shen, Liping

    2017-01-01

    Congenital cataract is both clinically diverse and genetically heterogeneous. To investigate the underlying genetic defect in three-generations of a Chinese family with autosomal dominant congenital cataracts, we recruited family members who underwent comprehensive ophthalmic examinations. A heterozygous missense mutation c.634G > C (p.G212R) substitution was identified in the MIP gene through target region capture sequencing. The prediction results of PolyPhen-2 and SIFT indicated that this ...

  13. Six missense mutations associated with type I and type II protein C deficiency and implications obtained from molecular modelling.

    Science.gov (United States)

    Zheng, Y Z; Sakata, T; Matsusue, T; Umeyama, H; Kato, H; Miyata, T

    1994-10-01

    The molecular basis of protein C deficiency was studied in three type I and three type II heterozygotes. Three probands showed thrombotic complications. All the exons and intron/exon junctions of the protein C gene were studied using a strategy combining by the polymerase chain reaction (PCR) amplification, single-strand conformational polymorphism (SSCP) analysis, and DNA sequencing of the PCR-amplified fragments. Six missense mutations were identified, including three novel ones. One was located in exon II, in which the initiating translation codon (ATG) encoding for Met at position -42 was replaced by ACG encoding for Thr. The other five were located in exon IX, and included TAC(Tyr399)-->CAC(His), CCG(Pro327)-->CTG(Leu), GAC(Asp359)-->AAC(Asn) in two cases, and GGG(Gly350)-->AGG(Arg). Four of the six missense mutations occurred in CG dinucleotide. Sequence analysis of the other exons excluded additional mutations. By restriction enzyme analysis, co-segregation of the mutation with protein C deficiency was observed in four families. The other two mutations at amino acid positions -42 and 350 were also considered to be associated with protein C deficiency due to the absence of these mutations in 50 normal individuals. A structural model of the protease domain of mutant activated protein C was constructed by the chimeric modelling method, and the resultant model suggested conformational changes due to each missense mutation identified in protein C deficiency. The present data also provide some evidence regarding the genetic heterogeneity of protein C deficiency.

  14. A missense mutation in the alpha-actinin 1 gene (ACTN1 is the cause of autosomal dominant macrothrombocytopenia in a large French family.

    Directory of Open Access Journals (Sweden)

    Paul Guéguen

    Full Text Available Inherited thrombocytopenia is a heterogeneous group of disorders characterized by a reduced number of blood platelets. Despite the identification of nearly 20 causative genes in the past decade, approximately half of all subjects with inherited thrombocytopenia still remain unexplained in terms of the underlying pathogenic mechanisms. Here we report a six-generation French pedigree with an autosomal dominant mode of inheritance and the identification of its genetic basis. Of the 55 subjects available for analysis, 26 were diagnosed with isolated macrothrombocytopenia. Genome-wide linkage analysis mapped a 10.9 Mb locus to chromosome 14 (14q22 with a LOD score of 7.6. Candidate gene analysis complemented by targeted next-generation sequencing identified a missense mutation (c.137GA; p.Arg46Gln in the alpha-actinin 1 gene (ACTN1 that segregated with macrothrombocytopenia in this large pedigree. The missense mutation occurred within actin-binding domain of alpha-actinin 1, a functionally critical domain that crosslinks actin filaments into bundles. The evaluation of cultured mutation-harboring megakaryocytes by electron microscopy and the immunofluorescence examination of transfected COS-7 cells suggested that the mutation causes disorganization of the cellular cytoplasm. Our study concurred with a recently published whole-exome sequence analysis of six small Japanese families with congenital macrothrombocytopenia, adding ACTN1 to the growing list of thrombocytopenia genes.

  15. Copy number variation and missense mutations of the agouti signaling protein (ASIP) gene in goat breeds with different coat colors.

    Science.gov (United States)

    Fontanesi, L; Beretti, F; Riggio, V; Gómez González, E; Dall'Olio, S; Davoli, R; Russo, V; Portolano, B

    2009-01-01

    In goats, classical genetic studies reported a large number of alleles at the Agouti locus with effects on coat color and pattern distribution. From these early studies, the dominant A(Wt) (white/tan) allele was suggested to cause the white color of the Saanen breed. Here, we sequenced the coding region of the goat ASIP gene in 6 goat breeds (Girgentana, Maltese, Derivata di Siria, Murciano-Granadina, Camosciata delle Alpi, and Saanen), with different coat colors and patterns. Five single nucleotide polymorphisms (SNPs) were identified, 3 of which caused missense mutations in conserved positions of the cysteine-rich carboxy-terminal domain of the protein (p.Ala96Gly, p.Cys126Gly, and p.Val128Gly). Allele and genotype frequencies suggested that these mutations are not associated or not completely associated with coat color in the investigated goat breeds. Moreover, genotyping and sequencing results, deviation from Hardy-Weinberg equilibrium, as well as allele copy number evaluation from semiquantitative fluorescent multiplex PCR, indicated the presence of copy number variation (CNV) in all investigated breeds. To confirm the presence of CNV and evaluate its extension, we applied a bovine-goat cross-species array comparative genome hybridization (aCGH) experiment using a custom tiling array based on bovine chromosome 13. aCGH results obtained for 8 goat DNA samples confirmed the presence of CNV affecting a region of less that 100 kb including the ASIP and AHCY genes. In Girgentana and Saanen breeds, this CNV might cause the A(Wt) allele, as already suggested for a similar structural mutation in sheep affecting the ASIP and AHCY genes, providing evidence for a recurrent interspecies CNV. However, other mechanisms may also be involved in determining coat color in these 2 breeds.

  16. Whole Exome Sequencing Leading to the Diagnosis of Dysferlinopathy with a Novel Missense Mutation (c.959G>C

    Directory of Open Access Journals (Sweden)

    Abhisek Swaika

    2016-01-01

    Full Text Available Dysferlinopathy is an uncommon, progressive muscular dystrophy that has a wide phenotypic variability and primarily supportive management (Nguyen et al., 2007; Narayanaswami et al., 2014. Amyloid myopathy is a distinct, rare disorder that can present similarly to inflammatory myopathies and requires a high clinical suspicion for early intervention to prolong survival. Amyloid myopathy is typically associated with other systemic manifestations of amyloidosis, but rare cases of isolated amyloid myopathy have been described (Mandl et al., 2000; Hull et al., 2001. Positive Congo red stains on tissue biopsy remain the gold standard for diagnosis (Spuler et al., 1998; Karacostas et al., 2005. A high clinical suspicion and meticulous diagnostic workup that includes novel techniques are necessary for identifying these rare disorders. We report a middle-aged man with progressive leg muscle weakness who was initially treated as having amyloid myopathy but was later diagnosed as having dysferlinopathy by Whole Exome Sequencing (WES analysis. We also report a novel missense mutation (c.959G>C to help correlate in any patient with presumed dysferlinopathy and to add to the already known genotype of this disorder.

  17. Identification of a novel missense mutation in the ALDH7A1 gene in two unrelated Tunisian families with pyridoxine-dependent epilepsy.

    Science.gov (United States)

    Tlili, Abdelaziz; Hamida Hentati, Nadia; Gargouri, Abdellatif; Fakhfakh, Faiza

    2013-01-01

    Pyridoxine-dependent Epilepsy (PDE) is a rare autosomal recessive disorder causing intractable seizures in neonates and infants. It is characterized by seizures that are resistant to common anticonvulsants, but patients respond well to the administration of pyridoxine. PDE is caused by ALDH7A1 genetic defect. Here, we report the disease-causative variant in the ALDH7A1 gene in two affected Tunisian families. Direct sequencing analysis revealed a novel missense mutation c.1364T>C (p.Leu455Pro). Using bioinformatic tools we suggested that this variant may have deleterious effects on ALDH7A1 protein structure and function.

  18. Autosomal dominant polycystic liver disease in a family without polycystic kidney disease associated with a novel missense protein kinase C substrate 80K-H mutation.

    Science.gov (United States)

    Peces, Ramón; Drenth, Joost P H; Te Morsche, Rene H M; González, Pedro; Peces, Carlos

    2005-12-28

    Polycystic liver disease (PLD) is characterized by the presence of multiple bile duct-derived epithelial cysts scattered in the liver parenchyma. PLD can manifest itself in patients with severe autosomal dominant polycystic kidney disease (ADPKD). Isolated autosomal dominant polycystic liver disease (ADPLD) is genetically distinct from PLD associated with ADPKD, although it may have similar pathogenesis and clinical manifestations. Recently, mutations in two causative genes for ADPLD, independently from ADPKD, have been identified. We report here a family (a mother and her daughter) with a severe form of ADPLD not associated with ADPKD produced by a novel missense protein kinase C substrate 80K-H (PRKCSH) mutation (R281W). This mutation causes a severe phenotype, since the two affected subjects manifested signs of portal hypertension. Doppler sonography, computed tomography (CT) and magnetic resonance (MR) imaging are effective in documenting the underlying lesions in a non-invasive way.

  19. Paroxysmal exercise-induced dyskinesia, writer's cramp, migraine with aura and absence epilepsy in twin brothers with a novel SLC2A1 missense mutation.

    Science.gov (United States)

    Urbizu, Aintzane; Cuenca-León, Ester; Raspall-Chaure, Miquel; Gratacòs, Margarida; Conill, Joan; Redecillas, Susana; Roig-Quilis, Manuel; Macaya, Alfons

    2010-08-15

    We report two monochorionic twins that progressively developed, between ages 5 and 10, a combination of episodic neurological disorders including paroxysmal exercise-induced dyskinesia, migraine without or with aura, absence seizures and writer's cramp. CSF/serum glucose ratio was moderately decreased in both patients. Mutational analysis of SLC2A1 gene identified a de novo heterozygous missense mutation in exon 4. This novel mutation has been previously showed to disrupt glucose transport in vitro. Both patients showed immediate and near-complete response to ketogenic diet. This clinical observation suggests that a high index of suspicion for GLUT1 deficiency syndrome is warranted in evaluating patients with multiple neurological paroxysmal events.

  20. Autosomal dominant polycystic liver disease in a family without polycystic kidney disease associated with a novel missense protein kinase C substrate 80K-H mutation

    Institute of Scientific and Technical Information of China (English)

    Ramón Peces; Joost PH Drenth; Rene HM te Morsche; Pedro González; Carlos Peces

    2005-01-01

    Polycystic liver disease (PLD) is characterized by the presence of multiple bile duct-derived epithelial cysts scattered in the liver parenchyma. PLD can manifest itself in patients with severe autosomal dominant polycystic kidney disease (ADPKD). Isolated autosomal dominant polycystic liver disease (ADPLD) is genetically distinct from PLD associated with ADPKD, although it may have similar pathogenesis and clinical manifestations.Recently, mutations in two causative genes for ADPLD,independently from ADPKD, have been identified. We report here a family (a mother and her daughter) with a severe form of ADPLD not associated with ADPKD produced by a novel missense protein kinase C substrate 80K-H (PRKCSH) mutation (R281W). This mutation causes a severe phenotype, since the two affected subjects manifested signs of portal hypertension. Doppler sonography, computed tomography (CT) and magnetic resonance (MR) imaging are effective in documenting the underlying lesions in a non-invasive way.

  1. Feline congenital erythropoietic porphyria: two homozygous UROS missense mutations cause the enzyme deficiency and porphyrin accumulation.

    Science.gov (United States)

    Clavero, Sonia; Bishop, David F; Giger, Urs; Haskins, Mark E; Desnick, Robert J

    2010-01-01

    The first feline model of human congenital erythropoietic porphyria (CEP) due to deficient uroporphyrinogen III synthase (URO-synthase) activity was identified by its characteristic clinical phenotype, and confirmed by biochemical and molecular genetic studies. The proband, an adult domestic shorthair cat, had dark-red urine and brownish discolored teeth with red fluorescence under ultraviolet light. Biochemical studies demonstrated markedly increased uroporphyrinogen I in urine and plasma (2,650- and 10,700-fold greater than wild type, respectively), whereas urinary 5-aminolevulinic acid and porphobilinogen were lower than normal. Erythrocytic URO-synthase activity was UROS gene revealed two missense mutations, c.140C>T (p.S47F) in exon 3 and c.331G>A (p.G111S) in exon 6, both of which were homozygous, presumably owing to parental consanguinity. Neither was present in 100 normal cat alleles. Prokaryotic expression and thermostability studies of the purified monomeric wild-type, p.S47F, p.G111S, and p.S47F/G111S enzymes showed that the p.S47F enzyme had 100% of wild-type specific activity but ~50% decreased thermostability, whereas the p.G111S and p.S47F/G111S enzymes had about 60% and 20% of wild-type specific activity, respectively, and both were markedly thermolabile. Molecular modeling results indicated that the less active/less stable p.G111S enzyme was further functionally impaired by a structural interaction induced by the presence of the S47F substitution. Thus, the synergistic interaction of two rare amino acid substitutions in the URO-synthase polypeptide caused the feline model of human CEP.

  2. A neonatal encephalopathy with seizures in standard poodle dogs with a missense mutation in the canine ortholog of ATF2.

    Science.gov (United States)

    Chen, Xuhua; Johnson, Gary S; Schnabel, Robert D; Taylor, Jeremy F; Johnson, Gayle C; Parker, Heidi G; Patterson, Edward E; Katz, Martin L; Awano, Tomoyuki; Khan, Shahwanaz; O'Brien, Dennis P

    2008-02-01

    Neonatal encephalopathy with seizures (NEWS) is a previously undescribed autosomal recessive disease of standard poodle puppies. Affected puppies are small and weak at birth. Many die in their first week of life. Those surviving past 1 week develop ataxia, a whole-body tremor, and, by 4 to 6 weeks of age, severe generalized clonic-tonic seizures. None have survived to 7 weeks of age. Cerebella from affected puppies were reduced in size and often contained dysplastic foci consisting of clusters of intermixed granule and Purkinje neurons. We used deoxyribonucleic acid samples from related standard poodles to map the NEWS locus to a 2.87-Mb segment of CFA36, which contains the canine ortholog of ATF2. This gene encodes activating transcription factor 2 (ATF-2), which participates in the cellular responses to a wide variety of stimuli. We amplified and sequenced all coding regions of canine ATF2 from a NEWS-affected puppy and identified a T > G transversion that predicts a methionine-to-arginine missense mutation at amino acid position 51. Methionine-51 lies within a hydrophobic docking site for mitogen-activated protein kinases that activate ATF-2 so the arginine substitution is likely to interfere with ATF-2 activation. All 20 NEWS-affected puppies in the standard poodle family were homozygous for the mutant G allele. The 58 clinically normal family members were either G/T heterozygotes or homozygous for the ancestral T allele. There are no previous reports of spontaneous ATF2 mutations in people or animals; however, atf2-knockout mice have cerebellar lesions that are similar to those in puppies with NEWS.

  3. A Novel Rasopathy Caused by Recurrent De Novo Missense Mutations In PPP1CB Closely Resembles Noonan Syndrome with Loose Anagen Hair

    Science.gov (United States)

    Gripp, Karen W.; Aldinger, Kimberly A.; Bennett, James T.; Baker, Laura; Tusi, Jessica; Powell-Hamilton, Nina; Stabley, Deborah; Sol-Church, Katia; Timms, Andrew E.; Dobyns, William B.

    2016-01-01

    Noonan syndrome is a rasopathy caused by mutations in multiple genes encoding components of the RAS/MAPK pathway. Despite its variable phenotype, limited genotype-phenotype correlations exist. Noonan syndrome with loose anagen hair (NS-LAH) is characterized by its distinctive hair anomalies, developmental differences and structural brain abnormalities and is caused by a single recurrent missense SHOC2 mutation. SHOC2 forms a complex with protein phosphatase 1 (PP1C). Protein phosphatases counterbalance kinases and control activation of signaling proteins, such as the mitogen activated protein kinases of the RAS/MAPK pathway. Here we report four patients with de novo missense mutations in protein phosphatase 1 catalytic subunit beta (PPP1CB), sharing a recognizable phenotype. Three individuals had the recurrent PPP1CB c.146G>C, p.Pro49Arg mutation, the fourth had a c.166G>C, p.Ala56Pro change. All had relative or absolute macrocephaly, low-set and posteriorly angulated ears and developmental delay. Slow growing and/or sparse hair and/or an unruly hair texture was present in all. Three individuals had feeding difficulties requiring feeding tubes. One of two males had cryptorchidism, another had pectus excavatum. Short stature was present in three. A female with the recurrent mutation had a Dandy-Walker malformation and optic nerve hypoplasia. Mild ventriculomegaly occurred in all, cerebellar tonsillar ectopia was seen in two and progressed to Chiari 1 malformation in one individual. Based on the combination of phenotypic findings and PPP1CB’s effect on RAF dephosphorylation within the RAS/MAPK pathway, this novel condition can be considered a rasopathy, most similar to NS-LAH. Collectively, these mutations meet the standardized criteria for pathogenicity. PMID:27264673

  4. Mucopolysaccharidosis IVA: Identification of a common missense mutation I113F in the N-Acetylgalactosamine-6-sulfate sulfatase gene

    Energy Technology Data Exchange (ETDEWEB)

    Tomatsu, Shunji; Fukuda, Seiji; Rezvi, Maruf [Univ. School of Medicine, Gifu (Japan)] [and others

    1995-09-01

    Mucopolysaccharidosis IVA is an autosomal recessive lysosomal storage disorder caused by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS). The recent isolation and characterization of cDNA and genomic sequences encoding GALNS has facilitated identification of the molecular lesions that cause MPS IVA. We identified a common missense mutation among Caucasian MPS IVA patients. The mutation was originally detected by SSCP, and successive sequencing revealed an A{yields}T transversion at nt 393. This substitution altered the isoleucine at position 113 to phenylalanine (I113F) in the 622 amino acid GALNS protein and was associated with a severe phenotype in a homozygote. Compound heterogzygotes with one I113F-allele mutation have a wide range of clinical phenotypes. Transfection experiments in GALNS-deficient fibroblasts revealed that the mutation drastically reduces the enzyme activity of GALNS. Allele-specific oligonucleotide or SSCP analysis indicated that this mutation accounted for 22.5% (9/40) of unrelated MPS IVA chromosomes from 23 Caucasian patients, including 6 consanguineous cases. Of interest, the I1e 113{yields}Phe substitution occurred in only Caucasian MPS IVA patients and in none of the GALNS alleles of 20 Japanese patients. These findings identify a frequent missense mutation among MPS IVA patients of Caucasian ancestry that results in severe MPS IVA when homoallelic, and will facilitate molecular diagnosis of most such patients and identification of heterozygous carriers. In addition to this common mutation, 10 different point mutations and 2 small deletions were detected, suggesting allelic heterogeneity in GALNS gene. 32 refs., 2 figs., 3 tabs.

  5. Frequent heterogeneous missense mutations of GGAP2 in prostate cancer: implications for tumor biology, clonality and mutation analysis.

    Directory of Open Access Journals (Sweden)

    Yi Cai

    Full Text Available Prostate cancer is the most common visceral malignancy in Western men and a major cause of cancer deaths. Increased activation of the AKT and NFkB pathways have been identified as critical steps in prostate cancer initiation and progression. GGAP2 (GTP-binding and GTPase activating protein 2 is a multidomain protein that contains an N-terminal Ras homology domain (GTPase, followed by a PH domain, a C-terminal GAP domain and an ankyrin repeat domain. GGAP2 can directly activate signaling via both the AKT and NFkB pathways and acts as a node of crosstalk between these pathways. Increased GGAP2 expression is present in three quarters of prostate cancers. Mutations of GGAP2 have been reported in cell lines from other malignancies. We therefore analyzed 84 prostate cancer tissues and 43 benign prostate tissues for somatic mutations in GGAP2 by direct sequencing of individual clones derived from the GAP and GTPase domains of normal and tumor tissue. Overall, half of cancers contained mutant GAP domain clones and in 20% of cancers, 30% or more of clones were mutant in the GAP domain. Surprisingly, the mutations were heterogeneous and nonclonal, with multiple different mutations being present in many tumors. Similar findings were observed in the analysis of the GTPase domain. Mutant GGAP2 proteins had significantly higher transcriptional activity using AP-1 responsive reporter constructs when compared to wild-type protein. Furthermore, the presence of these mutations was associated with aggressive clinical behavior. The presence of high frequency nonclonal mutations of a single gene is novel and represents a new mode of genetic alteration that can promote tumor progression. Analysis of mutations in cancer has been used to predict outcome and guide therapeutic target identification but such analysis has focused on clonal mutations. Our studies indicate that in some cases high frequency nonclonal mutations may need to be assessed as well.

  6. Frequent heterogeneous missense mutations of GGAP2 in prostate cancer: implications for tumor biology, clonality and mutation analysis.

    Science.gov (United States)

    Cai, Yi; Wang, Jianghua; Ren, Chengxi; Ittmann, Michael

    2012-01-01

    Prostate cancer is the most common visceral malignancy in Western men and a major cause of cancer deaths. Increased activation of the AKT and NFkB pathways have been identified as critical steps in prostate cancer initiation and progression. GGAP2 (GTP-binding and GTPase activating protein 2) is a multidomain protein that contains an N-terminal Ras homology domain (GTPase), followed by a PH domain, a C-terminal GAP domain and an ankyrin repeat domain. GGAP2 can directly activate signaling via both the AKT and NFkB pathways and acts as a node of crosstalk between these pathways. Increased GGAP2 expression is present in three quarters of prostate cancers. Mutations of GGAP2 have been reported in cell lines from other malignancies. We therefore analyzed 84 prostate cancer tissues and 43 benign prostate tissues for somatic mutations in GGAP2 by direct sequencing of individual clones derived from the GAP and GTPase domains of normal and tumor tissue. Overall, half of cancers contained mutant GAP domain clones and in 20% of cancers, 30% or more of clones were mutant in the GAP domain. Surprisingly, the mutations were heterogeneous and nonclonal, with multiple different mutations being present in many tumors. Similar findings were observed in the analysis of the GTPase domain. Mutant GGAP2 proteins had significantly higher transcriptional activity using AP-1 responsive reporter constructs when compared to wild-type protein. Furthermore, the presence of these mutations was associated with aggressive clinical behavior. The presence of high frequency nonclonal mutations of a single gene is novel and represents a new mode of genetic alteration that can promote tumor progression. Analysis of mutations in cancer has been used to predict outcome and guide therapeutic target identification but such analysis has focused on clonal mutations. Our studies indicate that in some cases high frequency nonclonal mutations may need to be assessed as well.

  7. Rapid Proteasomal Degradation of Mutant Proteins Is the Primary Mechanism Leading to Tumorigenesis in Patients With Missense AIP Mutations

    Science.gov (United States)

    Hernández-Ramírez, Laura C.; Martucci, Federico; Morgan, Rhodri M. L.; Trivellin, Giampaolo; Tilley, Daniel; Ramos-Guajardo, Nancy; Iacovazzo, Donato; D'Acquisto, Fulvio; Prodromou, Chrisostomos

    2016-01-01

    Context: The pathogenic effect of mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene (AIPmuts) in pituitary adenomas is incompletely understood. We have identified the primary mechanism of loss of function for missense AIPmuts. Objective: This study sought to analyze the mechanism/speed of protein turnover of wild-type and missense AIP variants, correlating protein half-life with clinical parameters. Design and Setting: Half-life and protein–protein interaction experiments and cross-sectional analysis of AIPmut positive patients' data were performed in a clinical academic research institution. Patients: Data were obtained from our cohort of pituitary adenoma patients and literature-reported cases. Interventions: Protein turnover of endogenous AIP in two cell lines and fifteen AIP variants overexpressed in HEK293 cells was analyzed via cycloheximide chase and proteasome inhibition. Glutathione-S-transferase pull-down and quantitative mass spectrometry identified proteins involved in AIP degradation; results were confirmed by coimmunoprecipitation and gene knockdown. Relevant clinical data was collected. Main Outcome Measures: Half-life of wild-type and mutant AIP proteins and its correlation with clinical parameters. Results: Endogenous AIP half-life was similar in HEK293 and lymphoblastoid cells (43.5 and 32.7 h). AIP variants were divided into stable proteins (median, 77.7 h; interquartile range [IQR], 60.7–92.9 h), and those with short (median, 27 h; IQR, 21.6–28.7 h) or very short (median, 7.7 h; IQR, 5.6–10.5 h) half-life; proteasomal inhibition rescued the rapid degradation of mutant proteins. The experimental half-life significantly correlated with age at diagnosis of acromegaly/gigantism (r = 0.411; P = .002). The FBXO3-containing SKP1–CUL1–F-box protein complex was identified as the E3 ubiquitin-ligase recognizing AIP. Conclusions: AIP is a stable protein, driven to ubiquitination by the SKP1–CUL1–F-box protein complex

  8. Familial tumoral calcinosis and hyperostosis-hyperphosphataemia syndrome are different manifestations of the same disease: novel missense mutations in GALNT3

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Leo; Joseph, Selvanayagam [Vinodhagan Memorial Hospital and Dr. Joseph' s Ortho Clinic, Department of Orthopaedic Surgery, Thanjavur (India); Hing, Sandra N.; Idowu, Bernadine D.; Delaney, David [Royal National Orthopaedic Hospital NHS Trust, Department of Histopathology, Stanmore, Middlesex (United Kingdom); Presneau, Nadege [University College London (UCL), Cancer Institute, London (United Kingdom); O' Donnell, Paul [Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, Stanmore, Middlesex (United Kingdom); University College London (UCL), Institute of Orthopaedics and Musculoskeletal Science, Stanmore (United Kingdom); University College London (UCL), The Institute of Orthopaedics and Musculoskeletal Science, London (United Kingdom); Diss, Tim [University College London Hospital (UCLH) NHS Trust, Rockefeller Building, Department of Histopathology, London (United Kingdom); Flanagan, Adrienne Margaret [Royal National Orthopaedic Hospital NHS Trust, Department of Histopathology, Stanmore, Middlesex (United Kingdom); University College London (UCL), Cancer Institute, London (United Kingdom); University College London Hospital (UCLH) NHS Trust, Rockefeller Building, Department of Histopathology, London (United Kingdom); University College London (UCL), Institute of Orthopaedics and Musculoskeletal Science, Stanmore (United Kingdom); Institute of Orthopaedics and Musculoskeletal Science, Stanmore, Middlesex (United Kingdom)

    2010-01-15

    To report on the biochemistry and clinical and genetic findings of two siblings, the younger sister presenting with recurrent bone pain of the radius and ulna, and medullary sclerosis, and the older brother with soft tissue calcific deposits (tumoral calcinosis) but who later developed bone pain. Both were found to be hyperphosphaturic. The index family comprised four individuals (father, mother, brother, sister). The affected siblings were the offspring of a non-consanguineous Indian family of Tamil origin. Bidirectional sequencing was performed on the DNA from the index family and on 160 alleles from a population of 80 unrelated unaffected control individuals of Tamil extraction and 72 alleles from individuals of non-Tamil origin. Two symptomatic siblings were found to harbour previously unreported compound heterozygous missense UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase 3 (GalNAc-transferase; GALNT3) mutations in exon 4 c.842A>G and exon 5 c.1097T>G. This sequence variation was not detected in the control DNA. This is the first report of siblings exhibiting stigmata of familial tumoral calcinosis and hyperostosis-hyperphosphataemia syndrome with documented evidence of autosomal recessive missense GALNT3 mutations. The findings from this family add further evidence to the literature that familial tumoral calcinosis and hyperostosis-hyperphosphataemia syndrome are manifestations of the same disease and highlight the importance of appropriate metabolic and genetic investigations. (orig.)

  9. Missense mutations in Desmocollin-2 N-terminus, associated with arrhythmogenic right ventricular cardiomyopathy, affect intracellular localization of desmocollin-2 in vitro

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    Basso Cristina

    2007-10-01

    Full Text Available Abstract Background Mutations in genes encoding desmosomal proteins have been reported to cause arrhythmogenic right ventricular cardiomyopathy (ARVC, an autosomal dominant disease characterised by progressive myocardial atrophy with fibro-fatty replacement. We screened 54 ARVC probands for mutations in desmocollin-2 (DSC2, the only desmocollin isoform expressed in cardiac tissue. Methods Mutation screening was performed by denaturing high-performance liquid chromatography and direct sequencing. To evaluate the pathogenic potentials of the DSC2 mutations detected in patients affected with ARVC, full-length wild-type and mutated cDNAs were cloned in eukaryotic expression vectors to obtain a fusion protein with green fluorescence protein (GFP; constructs were transfected in neonatal rat cardiomyocytes and in HL-1 cells. Results We identified two heterozygous mutations (c.304G>A (p.E102K and c.1034T>C (p.I345T in two probands and in four family members. The two mutations p.E102K and p.I345T map to the N-terminal region, relevant to adhesive interactions. In vitro functional studies demonstrated that, unlike wild-type DSC2, the two N-terminal mutants are predominantly localised in the cytoplasm. Conclusion The two missense mutations in the N-terminal domain affect the normal localisation of DSC2, thus suggesting the potential pathogenic effect of the reported mutations. Identification of additional DSC2 mutations associated with ARVC may result in increased diagnostic accuracy with implications for genetic counseling.

  10. Missense mutations in desmin associated with familial cardiac and skeletal myopathy.

    Science.gov (United States)

    Goldfarb, L G; Park, K Y; Cervenáková, L; Gorokhova, S; Lee, H S; Vasconcelos, O; Nagle, J W; Semino-Mora, C; Sivakumar, K; Dalakas, M C

    1998-08-01

    Desmin-related myopathy (OMIM 601419) is a familial disorder characterized by skeletal muscle weakness associated with cardiac conduction blocks, arrhythmias and restrictive heart failure, and by intracytoplasmic accumulation of desmin-reactive deposits in cardiac and skeletal muscle cells. The underlying molecular mechanisms are unknown. Involvement of the desmin gene (DES) has been excluded in three families diagnosed with desmin-related myopathy. We report two new families with desmin-related cardioskeletal myopathy associated with mutations in the highly conserved carboxy-terminal end of the desmin rod domain. A heterozygous A337P mutation was identified in a family with an adult-onset skeletal myopathy and mild cardiac involvement. Compound heterozygosity for two other mutations, A360P and N393I, was detected in a second family characterized by childhood-onset aggressive course of cardiac and skeletal myopathy.

  11. Catalytic deficiency of human aldolase B in hereditary fructose intolerance caused by a common missense mutation.

    Science.gov (United States)

    Cross, N C; Tolan, D R; Cox, T M

    1988-06-17

    Hereditary fructose intolerance (HFI) is a human autosomal recessive disease caused by a deficiency of aldolase B that results in an inability to metabolize fructose and related sugars. We report here the first identification of a molecular lesion in the aldolase B gene of an affected individual whose defective protein has previously been characterized. The mutation is a G----C transversion in exon 5 that creates a new recognition site for the restriction enzyme Ahall and results in an amino acid substitution (Ala----Pro) at position 149 of the protein within a region critical for substrate binding. Utilizing this novel restriction site and the polymerase chain reaction, the patient was shown to be homozygous for the mutation. Three other HFI patients from pedigrees unrelated to this individual were found to have the same mutation: two were homozygous and one was heterozygous. We suggest that this genetic lesion is a prevailing cause of hereditary fructose intolerance.

  12. Effects of naturally occurring missense mutations and G525V in the hydratase domain of human d-bifunctional protein on hydratase activity

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    Shirou Tsuchida

    2015-03-01

    Full Text Available d-bifunctional protein (d-BP deficiency is thought to lead to severe lipid metabolism disorders. To investigate the effect of naturally occurring missense mutations in the hydratase domain in d-BP, we constructed several d-BP hydratase variants and measured their activities. Missense mutations at sites whose conservation rates among 30 eukaryotes were < 70% did not affect hydratase activity. We predicted that missense mutations of highly conserved amino acids would markedly reduce activity. However, R562H and R562L, naturally occurring missense mutations of highly conserved amino acids, did not reduce activity. This result suggests that a missense mutation in a highly conserved amino acid does not always lead to severe lipid metabolism disorders. We also investigated the effect of G525V, which had been found in a mildly symptomatic patient with d-BP deficiency who was heterozygous for G525 and G658X. G525V markedly reduced hydratase activity. We had predicted that heterozygous G525V and G658X would lead to severely disordered lipid metabolism. However, the symptoms were inconsistent with this prediction. Characterizing mutations in the d-BP gene and the symptoms of d-BP deficiency may require pleiotropy, not only in vitro, studies.

  13. Missense mutations in the MEFV gene are associated with fibromyalgia syndrome and correlate with elevated IL-1beta plasma levels.

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    Jinong Feng

    Full Text Available BACKGROUND: Fibromyalgia syndrome (FMS, a common, chronic, widespread musculoskeletal pain disorder found in 2% of the general population and with a preponderance of 85% in females, has both genetic and environmental contributions. Patients and their parents have high plasma levels of the chemokines MCP-1 and eotaxin, providing evidence for both a genetic and an immunological/inflammatory origin for the syndrome (Zhang et al., 2008, Exp. Biol. Med. 233: 1171-1180. METHODS AND FINDINGS: In a search for a candidate gene affecting inflammatory pathways, among five screened in our patient samples (100 probands with FMS and their parents, we found 10 rare and one common alleles for MEFV, a gene in which various compound heterozygous mutations lead to Familial Mediterranean Fever (FMF. A total of 2.63 megabases of genomic sequence of the MEFV gene were scanned by direct sequencing. The collection of rare missense mutations (all heterozygotes and tested in the aggregate had a significant elevated frequency of transmission to affecteds (p = 0.0085, one-sided, exact binomial test. Our data provide evidence that rare missense variants of the MEFV gene are, collectively, associated with risk of FMS and are present in a subset of 15% of FMS patients. This subset had, on average, high levels of plasma IL-1beta (p = 0.019 compared to FMS patients without rare variants, unaffected family members with or without rare variants, and unrelated controls of unknown genotype. IL-1beta is a cytokine associated with the function of the MEFV gene and thought to be responsible for its symptoms of fever and muscle aches. CONCLUSIONS: Since misregulation of IL-1beta expression has been predicted for patients with mutations in the MEFV gene, we conclude that patients heterozygous for rare missense variants of this gene may be predisposed to FMS, possibly triggered by environmental factors.

  14. Missense UROS mutations causing congenital erythropoietic porphyria reduce UROS homeostasis that can be rescued by proteasome inhibition.

    Science.gov (United States)

    Blouin, Jean-Marc; Bernardo-Seisdedos, Ganeko; Sasso, Emma; Esteve, Julie; Ged, Cécile; Lalanne, Magalie; Sanz-Parra, Arantza; Urquiza, Pedro; de Verneuil, Hubert; Millet, Oscar; Richard, Emmanuel

    2017-02-21

    Congenital erythropoietic porphyria (CEP) is an inborn error of heme biosynthesis characterized by uroporphyrinogen III synthase (UROS) deficiency resulting in deleterious porphyrin accumulation in blood cells responsible for hemolytic anemia and cutaneous photosensitivity. We analyzed here the molecular basis of UROS impairment associated with twenty nine UROS missense mutations actually described in CEP patients. Using a computational and biophysical joint approach we predicted that most disease-causing mutations would affect UROS folding and stability. Through the analysis of enhanced green fluorescent protein-tagged versions of UROS enzyme we experimentally confirmed these data and showed that thermodynamic instability and premature protein degradation is a major mechanism accounting for the enzymatic deficiency associated with twenty UROS mutants in human cells. Since the intracellular loss in protein homeostasis is in excellent agreement with the in vitro destabilization, we used molecular dynamic simulation to rely structural 3D modification with UROS disability. We found that destabilizing mutations could be clustered within three types of mechanism according to side chain rearrangements or contact alterations within the pathogenic UROS enzyme so that the severity degree correlated with cellular protein instability. Furthermore, proteasome inhibition using bortezomib, a clinically available drug, significantly enhanced proteostasis of each unstable UROS mutant. Finally, we show evidence that abnormal protein homeostasis is a prevalent mechanism responsible for UROS deficiency and that modulators of UROS proteolysis such as proteasome inhibitors or chemical chaperones may represent an attractive therapeutic option to reduce porphyrin accumulation and prevent skin photosensitivity in CEP patients when the genotype includes a missense variant.

  15. Expression of a novel missense mutation found in the A4GALT gene of Amish individuals with the p phenotype.

    Science.gov (United States)

    Hellberg, Asa; Schmidt-Melbye, Anne-Christine; Reid, Marion E; Olsson, Martin L

    2008-03-01

    The rare p phenotype is found at a higher frequency in Amish people than in other populations. Different mutations in the 4-alpha-galactosyltransferase gene (A4GALT), responsible for synthesis of P(k) (Gb(3)) antigen, have been found to cause the P(k)-deficient p phenotype. The aim of this study was to explore the molecular background of the p phenotype in people of Amish origin. Twenty blood samples with the p phenotype, 19 of them from Amish individuals and 1 Pakistani, were investigated. Amplification of genomic DNA by polymerase chain reaction (PCR) and sequencing by capillary electrophoresis were performed. Blood donors of different geographic origin were screened with PCR-allele-specific primer to investigate whether the novel mutation occurs among individuals with common phenotypes. The mutation was also cloned into an expression vector and transfected to Namalwa cells, which do not normally express P(k). P(k) expression on the transfected cells and P/P(k) on red blood cells (RBCs), both with p and with common phenotypes, were analyzed by flow cytometry. All 20 samples were homozygous for 299C>T changing serine to leucine in a region that is highly conserved in homologous genes across species borders. The mutation was not found in any of the 500 alleles of blood donors investigated. P(k) expression was neither observed by serology and flow cytometry on p RBCs from Amish individuals nor following transfection of cells with constructs containing the novel missense mutation. A novel A4GALT missense mutation causes the p phenotype in Amish individuals.

  16. A rare missense mutation in CHRNA4 associates with smoking behavior and its consequences

    DEFF Research Database (Denmark)

    Thorgeirsson, T E; Steinberg, S; Reginsson, G W;

    2016-01-01

    Using Icelandic whole-genome sequence data and an imputation approach we searched for rare sequence variants in CHRNA4 and tested them for association with nicotine dependence. We show that carriers of a rare missense variant (allele frequency=0.24%) within CHRNA4, encoding an R336C substitution,...

  17. Autoimmune disease in a DFNA6/14/38 family carrying a novel missense mutation in WFS1.

    Science.gov (United States)

    Hildebrand, Michael S; Sorensen, Jessica L; Jensen, Maren; Kimberling, William J; Smith, Richard J H

    2008-09-01

    Most familial cases of autosomal dominant low frequency sensorineural hearing loss (LFSNHL) are attributable to mutations in the wolframin syndrome 1 (WFS1) gene at the DFNA6/14/38 locus. WFS1 mutations at this locus were first described in 2001 in six families segregating LFSNHL that was non-progressive below 2,000 Hz; the causative mutations all clustered in the C-terminal domain of the wolframin protein. Mutations in WFS1 also cause Wolfram syndrome (WS), an autosomal recessive neurodegenerative disorder defined by diabetes mellitus, optic atrophy and often deafness, while numerous single nucleotide polymorphisms (SNPs) in WFS1 have been associated with increased risk for diabetes mellitus, psychiatric illnesses and Parkinson disease. This study was conducted in an American family segregating autosomal dominant LFSNHL. Two hearing impaired family members also had autoimmune diseases-Graves disease (GD) and Crohn disease (CD). Based on the low frequency audioprofile, mutation screening of WFS1 was completed and a novel missense mutation (c.2576G --> A) that results in an arginine-to-glutamine substitution (p.R859Q) was identified in the C-terminal domain of the wolframin protein where most LFSNHL-causing mutations cluster. The family member with GD also carried polymorphisms in WFS1 that have been associated with other autoimmune diseases.

  18. Autosomal dominant coralliform cataract related to a missense mutation of the γD-crystallin gene

    Institute of Scientific and Technical Information of China (English)

    徐伟珍; 郑树; 徐世杰; 黄薇; 姚克; 张苏展

    2004-01-01

    Background Congenital cataract is a sight-threatening disease that affects about 1-6 cases per 10?@000 live births and causes 10%-30% of all blindness in children. About 25% of all cases are due to genetic defects. We identified autosomal dominant congenital coralliform cataracts-related genetic defect in a four-generation Chinese family.Methods Complete ophthalmological examinations were performed prior to lens extraction. Lens samples were then studied by electron microscopy. Genomic DNA from family members were examined using whole-genomic linkage analysis, with two-point logarithm of odds (LOD) scores calculated using the Linkage program package (version 5.1). Mutation analysis of candidate genes was performed by direct sequencing. Finally, a three-dimensional protein model was predicted using Swiss-Model (version 2.0).Results Eleven of the 23 examined individuals had congenital cataracts. Ultrastructure studies revealed crystal deposits in the lens, and granules extensively dispersed in transformed lens fiber cells. The maximum two-point LOD score, 3.5 at θ=0.1, was obtained for the marker D2S325. Mutation analysis of the γ-crystallin (CRYG) gene cluster identified a mutation (P23T) in exon 2 of γD-crystallin (CRYGD). Protein structure modeling demonstrated that the P23T mutation caused a subtle change on the surface of the γD protein.Conclusions The results suggest that the coralliform cataract phenotype is due to a mutated CRYGD gene, and that this sequence change is identical to one reported by Santhiya to be related to another distinct clinical condition, lamellar cataract. This study provides evidence that this same genetic defect may be associated with a different phenotype. This is the first report identifying the genetic defect associated with an autosomal dominant congenital coralliform cataract.

  19. A novel missense mutation (402C-->T) in exon 1 in the EDA gene in a family with X-linked hypohidrotic ectodermal dysplasia

    DEFF Research Database (Denmark)

    Hertz, Jens Michael; Nørgaard Hansen, K; Juncker, I

    1998-01-01

    families with hypohidrotic ectodermal dysplasia for mutation in exon 1 of the EDA-gene by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). In one large kindred we identified a novel missense mutation (402C-->T), which changes a histidine to tyrosine at position 54...

  20. Common pathogenic effects of missense mutations in the P-type ATPase ATP13A2 (PARK9 associated with early-onset parkinsonism.

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    Agata Podhajska

    Full Text Available Mutations in the ATP13A2 gene (PARK9 cause autosomal recessive, juvenile-onset Kufor-Rakeb syndrome (KRS, a neurodegenerative disease characterized by parkinsonism. KRS mutations produce truncated forms of ATP13A2 with impaired protein stability resulting in a loss-of-function. Recently, homozygous and heterozygous missense mutations in ATP13A2 have been identified in subjects with early-onset parkinsonism. The mechanism(s by which missense mutations potentially cause parkinsonism are not understood at present. Here, we demonstrate that homozygous F182L, G504R and G877R missense mutations commonly impair the protein stability of ATP13A2 leading to its enhanced degradation by the proteasome. ATP13A2 normally localizes to endosomal and lysosomal membranes in neurons and the F182L and G504R mutations disrupt this vesicular localization and promote the mislocalization of ATP13A2 to the endoplasmic reticulum. Heterozygous T12M, G533R and A746T mutations do not obviously alter protein stability or subcellular localization but instead impair the ATPase activity of microsomal ATP13A2 whereas homozygous missense mutations disrupt the microsomal localization of ATP13A2. The overexpression of ATP13A2 missense mutants in SH-SY5Y neural cells does not compromise cellular viability suggesting that these mutant proteins lack intrinsic toxicity. However, the overexpression of wild-type ATP13A2 may impair neuronal integrity as it causes a trend of reduced neurite outgrowth of primary cortical neurons, whereas the majority of disease-associated missense mutations lack this ability. Finally, ATP13A2 overexpression sensitizes cortical neurons to neurite shortening induced by exposure to cadmium or nickel ions, supporting a functional interaction between ATP13A2 and heavy metals in post-mitotic neurons, whereas missense mutations influence this sensitizing effect. Collectively, our study provides support for common loss-of-function effects of homozygous and

  1. A missense mutation in pstpip2 is associated with the murine autoinflammatory disorder chronic multifocal osteomyelitis.

    Science.gov (United States)

    Ferguson, Polly J; Bing, Xinyu; Vasef, Mohammed A; Ochoa, Luis A; Mahgoub, Amar; Waldschmidt, Thomas J; Tygrett, Lorraine T; Schlueter, Annette J; El-Shanti, Hatem

    2006-01-01

    Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disorder that primarily affects bone but is often accompanied by inflammation of the skin and/or gastrointestinal tract. The etiology is unknown but evidence suggests a genetic component to disease susceptibility. Although most cases of CRMO are sporadic, there is an autosomal recessive syndromic form of the disease, called Majeed syndrome, which is due to homozygous mutations in LPIN2. In addition, there is a phenotypically similar mouse, called cmo (chronic multifocal osteomyelitis) in which the disease is inherited as an autosomal recessive disorder. The cmo locus has been mapped to murine chromosome 18. In this report, we describe phenotypic abnormalities in the cmo mouse that include bone, cartilage and skin inflammation. Utilizing a backcross breeding strategy, we refined the cmo locus to a 1.3 Mb region on murine chromosome 18. Within the refined region was the gene pstpip2, which shares significant sequence homology to the PSTPIP1. Mutations in PSTPIP1 have been shown to cause the autoinflammatory disorder PAPA syndrome (pyogenic arthritis, pyoderma gangrenosum and acne). Mutation analysis, utilizing direct sequencing, revealed a single base pair change c.293T --> C in the pstpip2 gene resulting in a highly conserved leucine at amino acid 98 being replaced by a proline (L98P). No other mutations were found in the coding sequence of the remaining genes in the refined interval, although a 50 kb gap remains unexplored. These data suggest that mutations in pstpip2 may be the genetic explanation for the autoinflammatory phenotype seen in the cmo mouse.

  2. A COLQ missense mutation in Labrador Retrievers having congenital myasthenic syndrome.

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    Caitlin J Rinz

    Full Text Available Congenital myasthenic syndromes (CMSs are heterogeneous neuromuscular disorders characterized by skeletal muscle weakness caused by disruption of signal transmission across the neuromuscular junction (NMJ. CMSs are rarely encountered in veterinary medicine, and causative mutations have only been identified in Old Danish Pointing Dogs and Brahman cattle to date. Herein, we characterize a novel CMS in 2 Labrador Retriever littermates with an early onset of marked generalized muscle weakness. Because the sire and dam share 2 recent common ancestors, CMS is likely the result of recessive alleles inherited identical by descent (IBD. Genome-wide SNP profiles generated from the Illumina HD array for 9 nuclear family members were used to determine genomic inheritance patterns in chromosomal regions encompassing 18 functional candidate genes. SNP haplotypes spanning 3 genes were consistent with autosomal recessive transmission, and microsatellite data showed that only the segment encompassing COLQ was inherited IBD. COLQ encodes the collagenous tail of acetylcholinesterase, the enzyme responsible for termination of signal transduction in the NMJ. Sequences from COLQ revealed a variant in exon 14 (c.1010T>C that results in the substitution of a conserved amino acid (I337T within the C-terminal domain. Both affected puppies were homozygous for this variant, and 16 relatives were heterozygous, while 288 unrelated Labrador Retrievers and 112 dogs of other breeds were wild-type. A recent study in which 2 human CMS patients were found to be homozygous for an identical COLQ mutation (c.1010T>C; I337T provides further evidence that this mutation is pathogenic. This report describes the first COLQ mutation in canine CMS and demonstrates the utility of SNP profiles from nuclear family members for the identification of private mutations.

  3. A Case of Inflammatory Generalized Type of Peeling Skin Syndrome Possibly Caused by a Homozygous Missense Mutation of CDSN

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    Hiroshi Kawakami

    2014-10-01

    Full Text Available A 54-year-old Japanese woman had repetitive superficial skin peeling and ensuing erythematous changes in the sites since infancy. Her parents had a consanguineous marriage, and she was the only individual affected in her family tree. The erythematous changes seemed to worsen in the summer. Histologically, hyperkeratosis and splitting of the epidermis within the stratum corneum was noted, and electron microscopy revealed shedding of corneal cells in the horny layer and normal-looking corneodesmosomes. Gene analysis revealed a homozygous missense mutation at c.1358G>A in CDSN. Electron microscopic examination of the length and number of corneodesmosomes revealed statistically significant shortness and sparsity in the affected individual (mean ± SD 386.2 ± 149.5 nm compared with that of an age- and site-matched control (406.6 ± 182.3 nm. We speculate that this size shrinkage of corneodesmosomes might be the result of a missense mutation of CDSN and that this could be one of the factors contributing to the pathological process of skin peeling.

  4. Transcriptional regulation of the ABCC6 gene and the background of impaired function of missense disease-causing mutations

    Directory of Open Access Journals (Sweden)

    Tamás eArányi

    2013-03-01

    Full Text Available The human ABCC6 gene encodes an ABC transporter protein expressed primarily in the liver and to a lesser extent in the kidneys and the intestines. We review here the mechanisms of this restricted tissue-specific expression and the role of hepatocyte nuclear factor 4α which is responsible for the expression pattern. Detailed analyses uncovered further regulators of the expression of the gene pointing to an intronic primate-specific regulator region, an activator of the expression of the gene by binding C/EBPbeta, which interacts with other proteins acting in the proximal promoter. This regulatory network is affected by various environmental stimuli including oxidative stress and the ERK1/2 pathway. We also review here the structural and functional consequences of disease-causing missense mutations of ABCC6. A significant clustering of the missense disease-causing mutations was found at the domain-domain interfaces. This clustering means that the domain contacts are much less permissive to amino acid replacements than the rest of the protein. We summarize the experimental methods resulting in the identification of mutants with preserved transport activity but failure in intracellular targeting. These mutants are candidates for functional rescue by chemical chaperons. The results of such research can provide the basis of future allele-specific therapy of ABCC6-mediated disorders like pseudoxanthoma elasticum or the generalized arterial calcification in infancy.

  5. A novel mis-sense mutation (G1381A) in the G6PD gene identified in a Chinese man

    Institute of Scientific and Technical Information of China (English)

    任晓琴; 杜传书; 蒋玮莹; 陈路明; 林群娣; 何永蜀

    2001-01-01

    目的对中国云南省29例G6PD缺乏症患者检查新的基因突变型。 方法用NBT法作G6PD缺乏症筛查、SSCP、ACRS和DNA测序鉴定突变。结果29例中发现G1388A18例、C1004A1例、G1381A1例,另外9例未定型。其中1381突变为新的错义 突变。这一突变导致G6PD丙氨酸被苏氨酸置换(A461T),并导致一天然StuI酶切位点的消失,此特点可 用于该突变的鉴定。 结论我们发现一新的错义突变。此突变导致丙氨酸被苏氨酸置换(A461T),且此突变对酶活性降低是 重要的。%Objective To detect new mutations among 29 glucose-6-phosphatedehydrogenase (G6PD) deficient individuals from Yunnan province. Methods The nitroblue tetrazolium (NBT) method was used to screen G6PD deficient individuals. Mutation was identified by single strand conformation polymorphism (SSCP), amplification created restriction site (ACRS), amplification refractory mutation system (ARMS) and DNA sequencing. Results Among 29 cases, 18 cases of G1388A, 1 case of C1004A, and 1 case of G1381A were identified. Nine cases remained to be defined. The G1381A mutation is a novel mis-sense mutation, with a substitution of threonine for alanine (A461T). The resultant G6PD had reduced enzymatic activity. In addition, G1381A caused a restriction site of Stu I to disappear, providing a rapid method for the detection of this mutation. Conclusion A novel mis-sense mutation G1381A was found. This mutation results in a substitution of threonine for alanine, producing enzyme with reduced activity. The loss of the Stu I restriction site offers a rapid method for the detection of this mutation.

  6. Mutational and haplotype analyses of families with familial partial lipodystrophy (Dunnigan variety) reveal recurrent missense mutations in the globular C-terminal domain of lamin A/C.

    Science.gov (United States)

    Speckman, R A; Garg, A; Du, F; Bennett, L; Veile, R; Arioglu, E; Taylor, S I; Lovett, M; Bowcock, A M

    2000-04-01

    Familial partial lipodystrophy (FPLD), Dunnigan variety, is an autosomal dominant disorder characterized by marked loss of subcutaneous adipose tissue from the extremities and trunk but by excess fat deposition in the head and neck. The disease is frequently associated with profound insulin resistance, dyslipidemia, and diabetes. We have localized a gene for FPLD to chromosome 1q21-q23, and it has recently been proposed that nuclear lamin A/C is altered in FPLD, on the basis of a novel missense mutation (R482Q) in five Canadian probands. This gene had previously been shown to be altered in autosomal dominant Emery-Dreifuss muscular dystrophy (EDMD-AD) and in dilated cardiomyopathy and conduction-system disease. We examined 15 families with FPLD for mutations in lamin A/C. Five families harbored the R482Q alteration that segregated with the disease phenotype. Seven families harbored an R482W alteration, and one family harbored a G465D alteration. All these mutations lie within exon 8 of the lamin A/C gene-an exon that has also been shown to harbor different missense mutations that are responsible for EDMD-AD. Mutations could not be detected in lamin A/C in one FPLD family in which there was linkage to chromosome 1q21-q23. One family with atypical FPLD harbored an R582H alteration in exon 11 of lamin A. This exon does not comprise part of the lamin C coding region. All mutations in FPLD affect the globular C-terminal domain of the lamin A/C protein. In contrast, mutations responsible for dilated cardiomyopathy and conduction-system disease are observed in the rod domain of the protein. The FPLD mutations R482Q and R482W occurred on different haplotypes, indicating that they are likely to have arisen more than once.

  7. A novel missense mutation of the TYR gene in a pedigree with oculocutaneous albinism type 1 from China

    Institute of Scientific and Technical Information of China (English)

    LIN Yu-ying; WEI Ai-hua; ZHOU Zhi-yong; ZHU Wei; HE Xin; LIAN Shi

    2011-01-01

    Background The mutation of the tyrosinase (TYR) gene results in oculocutaneous albinism type 1 (OCA1),an autosomal recessive genetic disorder.OCA1 is the most common type of OCA in the Chinese population.Hence,the TYR gene was tested in this study.We also delineated the genetic analysis of OCA1 in a Chinese family.Methods Genomic DNA was isolated from the blood leukocytes of a proband and his family.Mutational analysis at the TYR locus by DNA sequencing was used to screen five exons,including the intron/exon junctions.A pedigree chart was drawn and the fundus of the eyes of the proband was also examined.Results A novel missense mutation p.1151S on exon 1,and homozygous TYR mutant alleles were identified in the proband.None of the mutants was identified among the 100 normal control subjects.Genetic analysis of the proband's wife showed normal alleles in the TYR gene.Thus,the fetus was predicated a carrier of OCA1 with a normal appearance.Conclusion This study provided new information about a novel mutation,p.l151S,in the TYR gene in a Chinese family with OCA1.Further investigation of the proband would be helpful to determine the effects of this mutation on TYR activity.

  8. Functional characterisation of a natural androgen receptor missense mutation (N771H) causing human androgen insensitivity syndrome.

    Science.gov (United States)

    Cai, J; Cai, L-Q; Hong, Y; Zhu, Y-S

    2012-05-01

    Androgen insensitivity syndrome (AIS) is an X-linked disorder due to mutations of androgen receptor (AR) gene. Various AR mutations have been identified, and the characterisation of these mutations greatly facilitates our understanding of AR structure-function. In this study, we have analysed an AR missense mutation (N771H) identified in patients with AIS. Functional analysis of the mutant AR was performed by in vitro mutagenesis-cotransfection assays. Compared to the wild-type AR, the dose-response curve of dihydrotestosterone-induced transactivation activity in the mutant AR was greatly shifted to the right and significantly decreased. However, the maximal efficacy of transactivation activity in the mutant AR was similar to that of the wild type. Receptor binding assay indicated that the mutant AR had an approximately 2.5-fold lower binding affinity to dihydrotestosterone compared to the wild type. Western blot analysis showed that the size and the expression level of mutant AR in transfected cells were comparable to the wild type. These data underscore the importance of asparagine at amino acid position 771 of human AR in normal ligand binding and normal receptor function, and a mutation at this position results in androgen insensitivity in affected subjects.

  9. Recurrent missense mutations in TMEM43 (ARVD5) due to founder effects cause arrhythmogenic cardiomyopathies in the UK and Canada

    KAUST Repository

    Haywood, Annika

    2012-11-15

    AimsAutosomal dominant arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) (in the group of arrhythmogenic cardiomyopathies) is a common cause of sudden cardiac death in young adults. It is both clinically and genetically heterogeneous, with 12 loci (ARVC/D1-12) and eight genes identified, the majority of which encode structural proteins of cardiac desmosomes. The most recent gene identified, TMEM43, causes disease due to a missense mutation in a non-desmosomal gene (p.S358L) in 15 extended families from Newfoundland, Canada. To determine whether mutations in TMEM43 cause ARVC/D and arrhythmogenic cardiomyopathy in other populations, we fully re-sequenced TMEM43 on 143 ARVC/D probands (families) from the UK and 55 probands (from 55 families) from Newfoundland.Methods and resultsBidirectional sequencing of TMEM43 including intron-exon boundaries revealed 33 variants, the majority located in non-coding regions of TMEM43. For the purpose of validation, families of probands with rare, potentially deleterious coding variants were subjected to clinical and molecular follow-up. Three missense variants of uncertain significance (p.R28W, p.E142K, p.R312W) were located in highly conserved regions of the TMEM43 protein. One variant (p.R312W) also co-segregated with relatives showing clinical signs of disease. Genotyping and expansion of the disease-associated haplotype in subjects with the p.R312W variant from Newfoundland, Canada, and the UK suggest common ancestry.ConclusionAlthough the p.R312W variant was found in controls (3/378), identification of an ancestral disease p R312W haplotype suggests that the p.R312W variant is a pathogenic founder mutation. © 2012 The Author.

  10. Structural Characterization of Missense Mutations Using High Resolution Mass Spectrometry: A Case Study of the Parkinson's-Related Protein, DJ-1

    Science.gov (United States)

    Ben-Nissan, Gili; Chotiner, Almog; Tarnavsky, Mark; Sharon, Michal

    2016-06-01

    Missense mutations that lead to the expression of mutant proteins carrying single amino acid substitutions are the cause of numerous diseases. Unlike gene lesions, insertions, deletions, nonsense mutations, or modified RNA splicing, which affect the length of a polypeptide, or determine whether a polypeptide is translated at all, missense mutations exert more subtle effects on protein structure, which are often difficult to evaluate. Here, we took advantage of the spectral resolution afforded by the EMR Orbitrap platform, to generate a mass spectrometry-based approach relying on simultaneous measurements of the wild-type protein and the missense variants. This approach not only considerably shortens the analysis time due to the concurrent acquisition but, more importantly, enables direct comparisons between the wild-type protein and the variants, allowing identification of even subtle structural changes. We demonstrate our approach using the Parkinson's-associated protein, DJ-1. Together with the wild-type protein, we examined two missense mutants, DJ-1A104T and DJ-1D149A, which lead to early-onset familial Parkinson's disease. Gas-phase, thermal, and chemical stability assays indicate clear alterations in the conformational stability of the two mutants: the structural stability of DJ-1D149A is reduced, whereas that of DJ-1A104T is enhanced. Overall, we anticipate that the methodology presented here will be applicable to numerous other missense mutants, promoting the structural investigations of multiple variants of the same protein.

  11. Microphthalmia in Texel sheep is associated with a missense mutation in the paired-like homeodomain 3 (PITX3) gene.

    Science.gov (United States)

    Becker, Doreen; Tetens, Jens; Brunner, Adrian; Bürstel, Daniela; Ganter, Martin; Kijas, James; Drögemüller, Cord

    2010-01-13

    Microphthalmia in sheep is an autosomal recessive inherited congenital anomaly found within the Texel breed. It is characterized by extremely small or absent eyes and affected lambs are absolutely blind. For the first time, we use a genome-wide ovine SNP array for positional cloning of a Mendelian trait in sheep. Genotyping 23 cases and 23 controls using Illumina's OvineSNP50 BeadChip allowed us to localize the causative mutation for microphthalmia to a 2.4 Mb interval on sheep chromosome 22 by association and homozygosity mapping. The PITX3 gene is located within this interval and encodes a homeodomain-containing transcription factor involved in vertebrate lens formation. An abnormal development of the lens vesicle was shown to be the primary event in ovine microphthalmia. Therefore, we considered PITX3 a positional and functional candidate gene. An ovine BAC clone was sequenced, and after full-length cDNA cloning the PITX3 gene was annotated. Here we show that the ovine microphthalmia phenotype is perfectly associated with a missense mutation (c.338G>C, p.R113P) in the evolutionary conserved homeodomain of PITX3. Selection against this candidate causative mutation can now be used to eliminate microphthalmia from Texel sheep in production systems. Furthermore, the identification of a naturally occurring PITX3 mutation offers the opportunity to use the Texel as a genetically characterized large animal model for human microphthalmia.

  12. Microphthalmia in Texel sheep is associated with a missense mutation in the paired-like homeodomain 3 (PITX3 gene.

    Directory of Open Access Journals (Sweden)

    Doreen Becker

    Full Text Available Microphthalmia in sheep is an autosomal recessive inherited congenital anomaly found within the Texel breed. It is characterized by extremely small or absent eyes and affected lambs are absolutely blind. For the first time, we use a genome-wide ovine SNP array for positional cloning of a Mendelian trait in sheep. Genotyping 23 cases and 23 controls using Illumina's OvineSNP50 BeadChip allowed us to localize the causative mutation for microphthalmia to a 2.4 Mb interval on sheep chromosome 22 by association and homozygosity mapping. The PITX3 gene is located within this interval and encodes a homeodomain-containing transcription factor involved in vertebrate lens formation. An abnormal development of the lens vesicle was shown to be the primary event in ovine microphthalmia. Therefore, we considered PITX3 a positional and functional candidate gene. An ovine BAC clone was sequenced, and after full-length cDNA cloning the PITX3 gene was annotated. Here we show that the ovine microphthalmia phenotype is perfectly associated with a missense mutation (c.338G>C, p.R113P in the evolutionary conserved homeodomain of PITX3. Selection against this candidate causative mutation can now be used to eliminate microphthalmia from Texel sheep in production systems. Furthermore, the identification of a naturally occurring PITX3 mutation offers the opportunity to use the Texel as a genetically characterized large animal model for human microphthalmia.

  13. Novel missense mutation in the GALNS gene in an affected patient with severe form of mucopolysaccharidosis type IVA.

    Science.gov (United States)

    Seyedhassani, Seyed Mohammad; Hashemi-Gorji, Feyzollah; Yavari, Mahdieh; Mirfakhraie, Reza

    2015-10-23

    Mucopolysaccharidosis type IVA (MPS IVA), also known as Morquio A, is an autosomal recessive disorder characterized by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS), which causes major skeletal and connective tissue abnormalities and affects multiple organ systems. In this study, one MPS IVA patient with a severe form from consanguine large Iranian family has been investigated. To find a mutation, all of the 14 exons and intron-exon junctions of GALNS gene were sequenced. Sequencing results were analyzed using bioinformatic analysis in order to predict probable pathogenic effect of the variant. One novel homozygous missense mutation in exon 5, c.542A>G (p.Y181C), was found in the proband. That was predicted as being probably pathogenic by bioinformatics analysis. Segregation and familial study confirmed this pathogenic mutation. In conclusion, we have identified the novel mutation responsible for MPS IVA in an Iranian patient to assist in the diagnosis, genetic counseling and prenatal diagnosis of the affected families. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. VHL missense mutations in the p53 binding domain show different effects on p53 signaling and HIFα degradation in clear cell renal cell carcinoma.

    Science.gov (United States)

    Razafinjatovo, Caroline Fanja; Stiehl, Daniel; Deininger, Eva; Rechsteiner, Markus; Moch, Holger; Schraml, Peter

    2017-02-07

    Clear cell Renal Cell Carcinoma (ccRCC) formation is connected to functional loss of the von Hippel-Lindau (VHL) gene. Recent data identified its gene product, pVHL, as a multifunctional adaptor protein which interacts with HIFα subunits but also with the tumor suppressor p53. p53 is hardly expressed and rarely mutated in most ccRCC. We showed that low and absent p53 expression correlated with the severity of VHL mutations in 262 analyzed ccRCC tissues. In contrast to nonsense and frameshift mutations which abrogate virtually all pVHL functions, missense mutations may rather influence one or few functions. Therefore, we focused on four VHL missense mutations, which affect the overlapping pVHL binding sites of p53 and Elongin C, by investigating their impact on HIFα degradation, p53 expression and signaling, as well as on cellular behavior using ccRCC cell lines and tissues. TP53 mRNA and its effector targets p21, Bax and Noxa, were altered both in engineered cell lines and in tumor tissues which carried the same missense mutations. Two of these mutations were not able to degrade HIFα whereas the remaining two mutations led to HIFα downregulation, suggesting the latter are p53 binding site-specific. The selected VHL missense mutations further enhanced tumor cell survival, but had no effects on cell proliferation. Whereas Sunitinib was able to efficiently reduce cell proliferation, Camptothecin was additionally able to increase apoptotic activity of the tumor cells. It is concluded that systematic characterization of the VHL mutation status may help optimizing targeted therapy for patients with metastatic ccRCC.

  15. A novel missense mutation in the signal peptide of the human POMC gene: a possible additional link between early-onset type 2 diabetes and obesity.

    Science.gov (United States)

    Mencarelli, Monica; Zulian, Alessandra; Cancello, Raffaella; Alberti, Luisella; Gilardini, Luisa; Di Blasio, Anna Maria; Invitti, Cecilia

    2012-12-01

    Rare mutations in several genes have a critical role in the control of homeostatic mechanisms such as food-intake, energy balance and glucose metabolism. In this study, we performed a mutational screening in a 58-year-old woman presenting early-onset type 2 diabetes and central obesity. The entire coding regions of MC4R, MC3R, HNF1A, GCK and POMC (pro-opiomelanocortin) genes were analyzed by direct sequencing. A new missense mutation was identified within the POMC gene signal peptide sequence, resulting in a heterozygous substitution of an arginine for a glycine at codon 15 (p.A15G) that was excluded in 300 healthy normal weight controls. The mutation segregated in the family and was associated with overweight, type 2 diabetes, hypertension and coronary heart disease in the carriers. Functional studies demonstrated that POMC protein was not detectable in β-TC3 cells transfected with A15G-POMC vector as well as in their culture media, despite POMC mRNA levels were comparable for amount and stability to those of wild-type-transfected cells. In silico RNA folding prediction indicated that the mutation gives rise to a different RNA secondary structure, suggesting that it might affect translation and protein synthesis. To the best of our knowledge, this is the first report addressing the functional consequences of a mutation in the signal peptide of POMC. These findings further support the hypothesis that POMC-derived peptides might have a role in the control of peripheral glucose metabolism and suggest that disruption of central POMC secretion might represent an additional link between type 2 diabetes and obesity.

  16. Independent role for presynaptic FMRP revealed by an FMR1 missense mutation associated with intellectual disability and seizures.

    Science.gov (United States)

    Myrick, Leila K; Deng, Pan-Yue; Hashimoto, Hideharu; Oh, Young Mi; Cho, Yongcheol; Poidevin, Mickael J; Suhl, Joshua A; Visootsak, Jeannie; Cavalli, Valeria; Jin, Peng; Cheng, Xiaodong; Warren, Stephen T; Klyachko, Vitaly A

    2015-01-27

    Fragile X syndrome (FXS) results in intellectual disability (ID) most often caused by silencing of the fragile X mental retardation 1 (FMR1) gene. The resulting absence of fragile X mental retardation protein 1 (FMRP) leads to both pre- and postsynaptic defects, yet whether the pre- and postsynaptic functions of FMRP are independent and have distinct roles in FXS neuropathology remain poorly understood. Here, we demonstrate an independent presynaptic function for FMRP through the study of an ID patient with an FMR1 missense mutation. This mutation, c.413G > A (R138Q), preserves FMRP's canonical functions in RNA binding and translational regulation, which are traditionally associated with postsynaptic compartments. However, neuronally driven expression of the mutant FMRP is unable to rescue structural defects at the neuromuscular junction in fragile x mental retardation 1 (dfmr1)-deficient Drosophila, suggesting a presynaptic-specific impairment. Furthermore, mutant FMRP loses the ability to rescue presynaptic action potential (AP) broadening in Fmr1 KO mice. The R138Q mutation also disrupts FMRP's interaction with the large-conductance calcium-activated potassium (BK) channels that modulate AP width. These results reveal a presynaptic- and translation-independent function of FMRP that is linked to a specific subset of FXS phenotypes.

  17. Neonatal diabetes in an infant of diabetic mother: same novel INS missense mutation in the mother and her offspring.

    Science.gov (United States)

    Ozturk, Mehmet Adnan; Kurtoglu, Selim; Bastug, Osman; Korkmaz, Levent; Daar, Ghaniya; Memur, Seyma; Halis, Hulya; Günes, Tamer; Hussain, Khalid; Ellard, Sian

    2014-07-01

    Neonatal diabetes is defined as an uncontrolled hyperglycemic state occurring within the first 6 months of life. It is a rare disease with an incidence of 1 to 90,000-250,000. It is usually a disease of genetic origin in which insulin gene mutations play the main role in the disease process. A baby, born to a mother who had previously been diagnosed with type 1 diabetes mellitus at 14 months of age, had a high blood sugar level within the first few hours after birth and was subsequently diagnosed as having neonatal diabetes mellitus. Baby and mother were identified as having a novel heterozygous insulin missense mutation, p.C109R. Difficulties occurred in both follow-up and feeding of the baby. Without the addition of the mother's milk, an appropriate calorie milk formula and isophane insulin were used for the baby during follow-up. Multiple mechanisms are responsible in the pathogenesis of neonatal diabetes mellitus. Insulin gene mutations are one of the factors in the development of neonatal diabetes mellitus. If a resistant hyperglycemic state persists for a long time among babies, especially in those with intrauterine growth retardation whose mothers are diabetic, the baby concerned should be followed-up carefully for the development of neonatal diabetes mellitus.

  18. Identification of a novel missense mutation of MIP in a Chinese family with congenital cataracts by target region capture sequencing

    Science.gov (United States)

    Jiang, Bo; chen, Yanhua; Xu, Baisheng; Hong, Nan; Liu, Rongrong; Qi, Ming; Shen, Liping

    2017-01-01

    Congenital cataract is both clinically diverse and genetically heterogeneous. To investigate the underlying genetic defect in three-generations of a Chinese family with autosomal dominant congenital cataracts, we recruited family members who underwent comprehensive ophthalmic examinations. A heterozygous missense mutation c.634G > C (p.G212R) substitution was identified in the MIP gene through target region capture sequencing. The prediction results of PolyPhen-2 and SIFT indicated that this mutation was likely to damage the structure and function of MIP. Confocal microscopy images showed that the intensity of the green fluorescent signal revealed much weaker signal from the mutant compared to the wild-type MIP. The expressed G212R-MIP was diminished and almost exclusively cytoplasmic in the HeLa cells; whereas the WT-MIP was stable dispersed throughout the cytoplasm, and it appeared to be in the membrane structure. Western blot analysis indicated that the protein expression level of the mutant form of MIP was remarkably reduced compared with that of the wild type, however, the mRNA levels of the wild-type and mutant cells were comparable. In conclusion, our study presented genetic and functional evidence for a novel MIP mutation of G212R, which leads to congenital progressive cortical punctate with or without Y suture. PMID:28059152

  19. Cenani-Lenz syndrome restricted to limb and kidney anomalies associated with a novel LRP4 missense mutation.

    Science.gov (United States)

    Khan, Tahir Naeem; Klar, J; Ali, Zafar; Khan, F; Baig, S M; Dahl, N

    2013-07-01

    Cenani-Lenz syndrome (CLS) is a rare autosomal recessive developmental disorder of the limbs. The disorder is characterized by complete syndactyly with metacarpal fusions and/or oligodactyly sometimes accompanied by radioulnar synostosis. The clinical expression is variable and kidney agenesis/hypoplasia, craniofacial dysmorphism and teeth abnormalities are frequent features as well as lower limb involvement. CLS was recently associated with mutations in the low-density lipoprotein receptor-related protein 4 (LRP4) gene and dysregulated canonical WNT signaling. We have identified a large consanguineous Pakistani pedigree with 9 members affected by CLS. The affected individuals present with a consistent expression of the syndrome restricted to the limbs and kidneys. Symptoms from the lower limb are mild or absent and there were no radioulnar synostosis or craniofacial involvement. Genetic analysis using autozygosity mapping and sequencing revealed homozygosity for a novel missense mutation c.2858T > C (p.L953P) in the LRP4 gene. The mutation is located in a region encoding the highly conserved low-density lipoprotein receptor repeat class B domain of LRP4. Our findings add to the genotype-phenotype correlations in CLS and support kidney anomalies as a frequent associated feature.

  20. Analysis of mucolipidosis II/III GNPTAB missense mutations identifies domains of UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase involved in catalytic function and lysosomal enzyme recognition.

    Science.gov (United States)

    Qian, Yi; van Meel, Eline; Flanagan-Steet, Heather; Yox, Alex; Steet, Richard; Kornfeld, Stuart

    2015-01-30

    UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase tags newly synthesized lysosomal enzymes with mannose 6-phosphate recognition markers, which are required for their targeting to the endolysosomal system. GNPTAB encodes the α and β subunits of GlcNAc-1-phosphotransferase, and mutations in this gene cause the lysosomal storage disorders mucolipidosis II and III αβ. Prior investigation of missense mutations in GNPTAB uncovered amino acids in the N-terminal region and within the DMAP domain involved in Golgi retention of GlcNAc-1-phosphotransferase and its ability to specifically recognize lysosomal hydrolases, respectively. Here, we undertook a comprehensive analysis of the remaining missense mutations in GNPTAB reported in mucolipidosis II and III αβ patients using cell- and zebrafish-based approaches. We show that the Stealth domain harbors the catalytic site, as some mutations in these regions greatly impaired the activity of the enzyme without affecting its Golgi localization and proteolytic processing. We also demonstrate a role for the Notch repeat 1 in lysosomal hydrolase recognition, as missense mutations in conserved cysteine residues in this domain do not affect the catalytic activity but impair mannose phosphorylation of certain lysosomal hydrolases. Rescue experiments using mRNA bearing Notch repeat 1 mutations in GNPTAB-deficient zebrafish revealed selective effects on hydrolase recognition that differ from the DMAP mutation. Finally, the mutant R587P, located in the spacer between Notch 2 and DMAP, was partially rescued by overexpression of the γ subunit, suggesting a role for this region in γ subunit binding. These studies provide new insight into the functions of the different domains of the α and β subunits.

  1. A Novel Missense Mutation (L296Q) in Cholesteryl Ester Transfer Protein Gene Related to Coronary Heart Disease

    Institute of Scientific and Technical Information of China (English)

    Ke-QinZHENG; Si-ZhongZHANG; LiZHANG; De-JiaHUANG; Lin-ChuanLIAO; Yi-PingHOU

    2004-01-01

    Cholesteryl ester transfer protein (CETP) is a key participant in the, reverse transport of cholesterol from the peripheral tissues to the liver. To understand the role that CETP gene plays in the pathogenesis of coronary heart disease (CHD), the promoter region, all 16 exons and adjacent intronic regions of CETP gene were screened for single nucleotide polymorphisms (SNPs) in 203 CHD patients and 209 controls by a combination of PCR, denaturing high performance liquid chromatography (DHPLC),molecular cloning, and DNA sequencing. A novel missense mutation in the CETP geve was identified. This mutation (L296Q) was a T-to-A conversion at codon 296 of exon 10 which replaced the codon for leucine (CTG) with the codon for glutamine (CAG). Association study revealed that L296Q mutation was associated with CHD with a significantly higher mutant allele frequency in the CHD patients than that in the controls (0.160 vs. 0.091,x2=9.014, P=0.003), and that the odds ratio for the development of CHD was 1.83 for the 296Q allele carriers relative to 296LL homozygotes. Statistical analyses demonstrated thai the mutant 296Q allele carrier patients displayed significantly higher total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) concentrations than non-carrier patients. The results of the present study suggest that the L296Q mutation is related to CHD, and the identification of new mutations in the CETP gene will afford the opportunity to investigate the relationship between CETP gene and CHD.

  2. Characterization of SH2D1A missense mutations identified in X-linked lymphoproliferative disease patients.

    Science.gov (United States)

    Morra, M; Simarro-Grande, M; Martin, M; Chen, A S; Lanyi, A; Silander, O; Calpe, S; Davis, J; Pawson, T; Eck, M J; Sumegi, J; Engel, P; Li, S C; Terhorst, C

    2001-09-28

    X-linked lymphoproliferative disease (XLP) is a primary immunodeficiency characterized by extreme susceptibility to Epstein-Barr virus. The XLP disease gene product SH2D1A (SAP) interacts via its SH2 domain with a motif (TIYXXV) present in the cytoplasmic tail of the cell-surface receptors CD150/SLAM, CD84, CD229/Ly-9, and CD244/2B4. Characteristically, the SH2D1A three-pronged interaction with Tyr(281) of CD150 can occur in absence of phosphorylation. Here we analyze the effect of SH2D1A protein missense mutations identified in 10 XLP families. Two sets of mutants were found: (i) mutants with a marked decreased protein half-life (e.g. Y7C, S28R, Q99P, P101L, V102G, and X129R) and (ii) mutants with structural changes that differently affect the interaction with the four receptors. In the second group, mutations that disrupt the interaction between the SH2D1A hydrophobic cleft and Val +3 of its binding motif (e.g. T68I) and mutations that interfere with the SH2D1A phosphotyrosine-binding pocket (e.g. C42W) abrogated SH2D1A binding to all four receptors. Surprisingly, a mutation in SH2D1A able to interfere with Thr -2 of the CD150 binding motif (mutant T53I) severely impaired non-phosphotyrosine interactions while preserving unaffected the binding of SH2D1A to phosphorylated CD150. Mutant T53I, however, did not bind to CD229 and CD224, suggesting that SH2D1A controls several critical signaling pathways in T and natural killer cells. Because no correlation is present between identified types of mutations and XLP patient clinical presentation, additional unidentified genetic or environmental factors must play a strong role in XLP disease manifestations.

  3. A novel missense adenine nucleotide translocator-1 gene mutation in a Greek adPEO family.

    Science.gov (United States)

    Napoli, L; Bordoni, A; Zeviani, M; Hadjigeorgiou, G M; Sciacco, M; Tiranti, V; Terentiou, A; Moggio, M; Papadimitriou, A; Scarlato, G; Comi, G P

    2001-12-26

    Autosomal dominant progressive external ophthalmoplegia (adPEO) is caused by mutations in at least three different genes: ANT1 (chromosome 4q34-35), TWINKLE, and POLG. The ANT1 gene encodes the adenine nucleotide translocator-1 (ANT1). We identified a heterozygous T293C mutation of the ANT1 gene in a Greek family with adPEO. The resulting leucine to proline substitution likely modifies the secondary structure of the ANT1 protein. ANT1 gene mutations may account for adPEO in families with different ethnic backgrounds.

  4. SMA-causing missense mutations in survival motor neuron (Smn) display a wide range of phenotypes when modeled in Drosophila.

    Science.gov (United States)

    Praveen, Kavita; Wen, Ying; Gray, Kelsey M; Noto, John J; Patlolla, Akash R; Van Duyne, Gregory D; Matera, A Gregory

    2014-08-01

    Mutations in the human survival motor neuron 1 (SMN) gene are the primary cause of spinal muscular atrophy (SMA), a devastating neuromuscular disorder. SMN protein has a well-characterized role in the biogenesis of small nuclear ribonucleoproteins (snRNPs), core components of the spliceosome. Additional tissue-specific and global functions have been ascribed to SMN; however, their relevance to SMA pathology is poorly understood and controversial. Using Drosophila as a model system, we created an allelic series of twelve Smn missense mutations, originally identified in human SMA patients. We show that animals expressing these SMA-causing mutations display a broad range of phenotypic severities, similar to the human disease. Furthermore, specific interactions with other proteins known to be important for SMN's role in RNP assembly are conserved. Intragenic complementation analyses revealed that the three most severe mutations, all of which map to the YG box self-oligomerization domain of SMN, display a stronger phenotype than the null allele and behave in a dominant fashion. In support of this finding, the severe YG box mutants are defective in self-interaction assays, yet maintain their ability to heterodimerize with wild-type SMN. When expressed at high levels, wild-type SMN is able to suppress the activity of the mutant protein. These results suggest that certain SMN mutants can sequester the wild-type protein into inactive complexes. Molecular modeling of the SMN YG box dimer provides a structural basis for this dominant phenotype. These data demonstrate that important structural and functional features of the SMN YG box are conserved between vertebrates and invertebrates, emphasizing the importance of self-interaction to the proper functioning of SMN.

  5. SMA-causing missense mutations in survival motor neuron (Smn display a wide range of phenotypes when modeled in Drosophila.

    Directory of Open Access Journals (Sweden)

    Kavita Praveen

    2014-08-01

    Full Text Available Mutations in the human survival motor neuron 1 (SMN gene are the primary cause of spinal muscular atrophy (SMA, a devastating neuromuscular disorder. SMN protein has a well-characterized role in the biogenesis of small nuclear ribonucleoproteins (snRNPs, core components of the spliceosome. Additional tissue-specific and global functions have been ascribed to SMN; however, their relevance to SMA pathology is poorly understood and controversial. Using Drosophila as a model system, we created an allelic series of twelve Smn missense mutations, originally identified in human SMA patients. We show that animals expressing these SMA-causing mutations display a broad range of phenotypic severities, similar to the human disease. Furthermore, specific interactions with other proteins known to be important for SMN's role in RNP assembly are conserved. Intragenic complementation analyses revealed that the three most severe mutations, all of which map to the YG box self-oligomerization domain of SMN, display a stronger phenotype than the null allele and behave in a dominant fashion. In support of this finding, the severe YG box mutants are defective in self-interaction assays, yet maintain their ability to heterodimerize with wild-type SMN. When expressed at high levels, wild-type SMN is able to suppress the activity of the mutant protein. These results suggest that certain SMN mutants can sequester the wild-type protein into inactive complexes. Molecular modeling of the SMN YG box dimer provides a structural basis for this dominant phenotype. These data demonstrate that important structural and functional features of the SMN YG box are conserved between vertebrates and invertebrates, emphasizing the importance of self-interaction to the proper functioning of SMN.

  6. Mutation-Structure-Function Relationship Based Integrated Strategy Reveals the Potential Impact of Deleterious Missense Mutations in Autophagy Related Proteins on Hepatocellular Carcinoma (HCC: A Comprehensive Informatics Approach

    Directory of Open Access Journals (Sweden)

    Faryal Mehwish Awan

    2017-01-01

    Full Text Available Autophagy, an evolutionary conserved multifaceted lysosome-mediated bulk degradation system, plays a vital role in liver pathologies including hepatocellular carcinoma (HCC. Post-translational modifications (PTMs and genetic variations in autophagy components have emerged as significant determinants of autophagy related proteins. Identification of a comprehensive spectrum of genetic variations and PTMs of autophagy related proteins and their impact at molecular level will greatly expand our understanding of autophagy based regulation. In this study, we attempted to identify high risk missense mutations that are highly damaging to the structure as well as function of autophagy related proteins including LC3A, LC3B, BECN1 and SCD1. Number of putative structural and functional residues, including several sites that undergo PTMs were also identified. In total, 16 high-risk SNPs in LC3A, 18 in LC3B, 40 in BECN1 and 43 in SCD1 were prioritized. Out of these, 2 in LC3A (K49A, K51A, 1 in LC3B (S92C, 6 in BECN1 (S113R, R292C, R292H, Y338C, S346Y, Y352H and 6 in SCD1 (Y41C, Y55D, R131W, R135Q, R135W, Y151C coincide with potential PTM sites. Our integrated analysis found LC3B Y113C, BECN1 I403T, SCD1 R126S and SCD1 Y218C as highly deleterious HCC-associated mutations. This study is the first extensive in silico mutational analysis of the LC3A, LC3B, BECN1 and SCD1 proteins. We hope that the observed results will be a valuable resource for in-depth mechanistic insight into future investigations of pathological missense SNPs using an integrated computational platform.

  7. [A young boy with elevated aminotransferases in physical examination--Two novel missense mutations associated with Wilson's disease were found].

    Science.gov (United States)

    Zhu, Yu; Deng, Si-Yan; Wan, Chao-Min

    2015-07-01

    A 3-year-old boy had abnormal liver function, which was found in physical examination, for 5 months before admission. He had no symptoms such as anorexia, poor appetite, and jaundice, had normal growth and development, and showed no hepatosplenomegaly. Laboratory examination revealed significantly reduced ceruloplasmin (35 mg/L), as well as negative hepatotropic virus, cytomegalovirus, and Epstein-Barr virus. There were normal muscle enzymes, blood glucose, and blood ammonia and negative liver-specific autoantibodies. The boy had negative K-F ring and normal 24-hour urine copper (0.56 μmol/L). The ATP7B gene testing for the boy, his sister, and their parents detected two novel missense mutations in the boy and his sister, i.e., compound heterozygous mutations in exon 7 (c.2075T>C, p.L692P) and exon 13 (c.3044T>C, p.L1015P), which were inherited from their father and mother, respectively. Wilson's disease was confirmed by genetic diagnosis in the boy and his sister. The boy and his sister were given a low-copper diet. The boy was administered with penicillamine for decoppering and zinc supplement against copper uptake. His sister received zinc supplement alone because no clinical symptoms were observed. The boy showed normal liver function in the reexamination after 3 months of treatment.

  8. A Missense Mutation in KCTD17 Causes Autosomal Dominant Myoclonus-Dystonia

    Science.gov (United States)

    Mencacci, Niccolo E.; Rubio-Agusti, Ignacio; Zdebik, Anselm; Asmus, Friedrich; Ludtmann, Marthe H.R.; Ryten, Mina; Plagnol, Vincent; Hauser, Ann-Kathrin; Bandres-Ciga, Sara; Bettencourt, Conceição; Forabosco, Paola; Hughes, Deborah; Soutar, Marc M.P.; Peall, Kathryn; Morris, Huw R.; Trabzuni, Daniah; Tekman, Mehmet; Stanescu, Horia C.; Kleta, Robert; Carecchio, Miryam; Zorzi, Giovanna; Nardocci, Nardo; Garavaglia, Barbara; Lohmann, Ebba; Weissbach, Anne; Klein, Christine; Hardy, John; Pittman, Alan M.; Foltynie, Thomas; Abramov, Andrey Y.; Gasser, Thomas; Bhatia, Kailash P.; Wood, Nicholas W.

    2015-01-01

    Myoclonus-dystonia (M-D) is a rare movement disorder characterized by a combination of non-epileptic myoclonic jerks and dystonia. SGCE mutations represent a major cause for familial M-D being responsible for 30%–50% of cases. After excluding SGCE mutations, we identified through a combination of linkage analysis and whole-exome sequencing KCTD17 c.434 G>A p.(Arg145His) as the only segregating variant in a dominant British pedigree with seven subjects affected by M-D. A subsequent screening in a cohort of M-D cases without mutations in SGCE revealed the same KCTD17 variant in a German family. The clinical presentation of the KCTD17-mutated cases was distinct from the phenotype usually observed in M-D due to SGCE mutations. All cases initially presented with mild myoclonus affecting the upper limbs. Dystonia showed a progressive course, with increasing severity of symptoms and spreading from the cranio-cervical region to other sites. KCTD17 is abundantly expressed in all brain regions with the highest expression in the putamen. Weighted gene co-expression network analysis, based on mRNA expression profile of brain samples from neuropathologically healthy individuals, showed that KCTD17 is part of a putamen gene network, which is significantly enriched for dystonia genes. Functional annotation of the network showed an over-representation of genes involved in post-synaptic dopaminergic transmission. Functional studies in mutation bearing fibroblasts demonstrated abnormalities in endoplasmic reticulum-dependent calcium signaling. In conclusion, we demonstrate that the KCTD17 c.434 G>A p.(Arg145His) mutation causes autosomal dominant M-D. Further functional studies are warranted to further characterize the nature of KCTD17 contribution to the molecular pathogenesis of M-D. PMID:25983243

  9. A novel missense mutation in SUCLG1 associated with mitochondrial DNA depletion, encephalomyopathic form, with methylmalonic aciduria

    DEFF Research Database (Denmark)

    Østergaard, Elsebet; Schwartz, Marianne; Batbayli, Mustafa;

    2010-01-01

    Mitochondrial DNA depletion, encephalomyopathic form, with methylmalonic aciduria is associated with mutations in SUCLA2, the gene encoding a beta subunit of succinate-CoA ligase, where 17 patients have been reported. Mutations in SUCLG1, encoding the alpha subunit of the enzyme, have been reported...

  10. Novel homozygous missense mutation in GAN associated with Charcot-Marie-Tooth disease type 2 in a large consanguineous family from Israel.

    Science.gov (United States)

    Aharoni, Sharon; Barwick, Katy E S; Straussberg, Rachel; Harlalka, Gaurav V; Nevo, Yoram; Chioza, Barry A; McEntagart, Meriel M; Mimouni-Bloch, Aviva; Weedon, Michael; Crosby, Andrew H

    2016-11-16

    CMT-2 is a clinically and genetically heterogeneous group of peripheral axonal neuropathies characterized by slowly progressive weakness and atrophy of distal limb muscles resulting from length-dependent motor and sensory neurodegeneration. Classical giant axonal neuropathy (GAN) is an autosomal recessively inherited progressive neurodegenerative disorder of the peripheral and central nervous systems, typically diagnosed in early childhood and resulting in death by the end of the third decade. Distinctive phenotypic features are the presence of "kinky" hair and long eyelashes. The genetic basis of the disease has been well established, with over 40 associated mutations identified in the gene GAN, encoding the BTB-KELCH protein gigaxonin, involved in intermediate filament regulation. An Illumina Human CytoSNP-12 array followed by whole exome sequence analysis was used to identify the disease associated gene mutation in a large consanguineous family diagnosed with Charcot-Marie-Tooth disease type 2 (CMT-2) from which all but one affected member had straight hair. Here we report the identification of a novel GAN missense mutation underlying the CMT-2 phenotype observed in this family. Although milder forms of GAN, with and without the presence of kinky hair have been reported previously, a phenotype distinct from that was investigated in this study. All family members lacked common features of GAN, including ataxia, nystagmus, intellectual disability, seizures, and central nervous system involvement. Our findings broaden the spectrum of phenotypes associated with GAN mutations and emphasize a need to proceed with caution when providing families with diagnostic or prognostic information based on either clinical or genetic findings alone.

  11. Identification and Analysis of Driver Missense Mutations Using Rotation Forest with Feature Selection

    Directory of Open Access Journals (Sweden)

    Xiuquan Du

    2014-01-01

    Full Text Available Identifying cancer-associated mutations (driver mutations is critical for understanding the cellular function of cancer genome that leads to activation of oncogenes or inactivation of tumor suppressor genes. Many approaches are proposed which use supervised machine learning techniques for prediction with features obtained by some databases. However, often we do not know which features are important for driver mutations prediction. In this study, we propose a novel feature selection method (called DX from 126 candidate features’ set. In order to obtain the best performance, rotation forest algorithm was adopted to perform the experiment. On the train dataset which was collected from COSMIC and Swiss-Prot databases, we are able to obtain high prediction performance with 88.03% accuracy, 93.9% precision, and 81.35% recall when the 11 top-ranked features were used. Comparison with other various techniques in the TP53, EGFR, and Cosmic2plus datasets shows the generality of our method.

  12. A rare missense mutation in CHRNA4 associates with smoking behavior and its consequences.

    Science.gov (United States)

    Thorgeirsson, T E; Steinberg, S; Reginsson, G W; Bjornsdottir, G; Rafnar, T; Jonsdottir, I; Helgadottir, A; Gretarsdottir, S; Helgadottir, H; Jonsson, S; Matthiasson, S E; Gislason, T; Tyrfingsson, T; Gudbjartsson, T; Isaksson, H J; Hardardottir, H; Sigvaldason, A; Kiemeney, L A; Haugen, A; Zienolddiny, S; Wolf, H J; Franklin, W A; Panadero, A; Mayordomo, J I; Hall, I P; Rönmark, E; Lundbäck, B; Dirksen, A; Ashraf, H; Pedersen, J H; Masson, G; Sulem, P; Thorsteinsdottir, U; Gudbjartsson, D F; Stefansson, K

    2016-05-01

    Using Icelandic whole-genome sequence data and an imputation approach we searched for rare sequence variants in CHRNA4 and tested them for association with nicotine dependence. We show that carriers of a rare missense variant (allele frequency=0.24%) within CHRNA4, encoding an R336C substitution, have greater risk of nicotine addiction than non-carriers as assessed by the Fagerstrom Test for Nicotine Dependence (P=1.2 × 10(-4)). The variant also confers risk of several serious smoking-related diseases previously shown to be associated with the D398N substitution in CHRNA5. We observed odds ratios (ORs) of 1.7-2.3 for lung cancer (LC; P=4.0 × 10(-4)), chronic obstructive pulmonary disease (COPD; P=9.3 × 10(-4)), peripheral artery disease (PAD; P=0.090) and abdominal aortic aneurysms (AAAs; P=0.12), and the variant associates strongly with the early-onset forms of LC (OR=4.49, P=2.2 × 10(-4)), COPD (OR=3.22, P=2.9 × 10(-4)), PAD (OR=3.47, P=9.2 × 10(-3)) and AAA (OR=6.44, P=6.3 × 10(-3)). Joint analysis of the four smoking-related diseases reveals significant association (P=6.8 × 10(-5)), particularly for early-onset cases (P=2.1 × 10(-7)). Our results are in agreement with functional studies showing that the human α4β2 isoform of the channel containing R336C has less sensitivity for its agonists than the wild-type form following nicotine incubation.

  13. Structural and functional analysis of rare missense mutations in human chorionic gonadotrophin β-subunit

    DEFF Research Database (Denmark)

    Nagirnaja, Liina; Venclovas, Česlovas; Rull, Kristiina

    2012-01-01

    from Estonia, Finland and Denmark] using PCR-restriction fragment length polymorphism. The mutation CGB5 p.Val56Leu (rs72556325) was identified in a single heterozygous RM patient and caused a structural hindrance in the formation of the hCGα/β dimer. Although the amount of the mutant hCGβ assembled...

  14. Rare missense mutations in P2RY11 in narcolepsy with cataplexy.

    Science.gov (United States)

    Degn, Matilda; Dauvilliers, Yves; Dreisig, Karin; Lopez, Régis; Pfister, Corinne; Pradervand, Sylvain; Rahbek Kornum, Birgitte; Tafti, Mehdi

    2017-06-01

    The sleep disorder narcolepsy with cataplexy is characterized by a highly specific loss of hypocretin (orexin) neurons, leading to the hypothesis that the condition is caused by an immune or autoimmune mechanism. All genetic variants associated with narcolepsy are immune-related. Among these are single nucleotide polymorphisms in the P2RY11-EIF3G locus. It is unknown how these genetic variants affect narcolepsy pathogenesis and whether the effect is directly related to P2Y11 signalling or EIF3G function. Exome sequencing in 18 families with at least two affected narcolepsy with cataplexy subjects revealed non-synonymous mutations in the second exon of P2RY11 in two families, and P2RY11 re-sequencing in 250 non-familial cases and 135 healthy control subjects revealed further six different non-synonymous mutations in the second exon of P2RY11 in seven patients. No mutations were found in healthy controls. Six of the eight narcolepsy-associated P2Y11 mutations resulted in significant functional deficits in P2Y11 signalling through both Ca2+ and cAMP signalling pathways. In conclusion, our data show that decreased P2Y11 signalling plays an important role in the development of narcolepsy with cataplexy. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. A homozygous missense mutation in the IRBP gene (RBP3) associated with autosomal recessive retinitis pigmentosa.

    NARCIS (Netherlands)

    Hollander, A.I. den; McGee, T.L.; Ziviello, C.; Banfi, S.; Dryja, T.P.; Gonzalez-Fernandez, F.; Ghosh, D.; Berson, E.L.

    2009-01-01

    PURPOSE: Interphotoreceptor retinoid-binding protein (IRBP) has been considered essential for normal rod and cone function, as it mediates the transport of retinoids between the photoreceptors and the retinal pigment epithelium. This study was performed to determine whether mutations in the IRBP gen

  16. X-linked hydrocephalus : A novel missense mutation in the L1CAM gene

    NARCIS (Netherlands)

    Sztriha, L; Vos, YJ; Verlind, E; Johansen, J; Berg, B

    2002-01-01

    X-linked hydrocephalus is associated with mutations in the L1 neuronal cell adhesion molecule gene. L1 protein plays a key role in neurite outgrowth, axonal guidance, and pathfinding during the development of the nervous system. A male is described with X-linked hydrocephalus who had multiple small

  17. A Novel Missense Mutation (L296Q) in Cholesteryl Ester Transfer Protein Gene Related to Coronary Heart Disease

    Institute of Scientific and Technical Information of China (English)

    Ke-Qin ZHENG; Si-Zhong ZHANG; Li ZHANG; De-Jia HUANG; Lin-Chuan LIAO; Yi-Ping HOU

    2004-01-01

    Cholesteryl ester transfer protein (CETP) is a key participant in the reverse transport ofcholesterol from the peripheral tissues to the liver. To understand the role that CETP gene plays in thepathogenesis of coronary heart disease (CHD), the promoter region, all 16 exons and adjacent intronicregions of CETP gene were screened for single nucleotide polymorphisms (SNPs) in 203 CHD patients and209 controls by a combination of PCR, denaturing high performance liquid chromatography (DHPLC),molecular cloning, and DNA sequencing. A novel missense mutation in the CETP gene was identified. Thismutation (L296Q) was a T-to-A conversion at codon 296 of exon 10 which replaced the codon for leucine(CTG) with the codon for glutamine (CAG). Association study revealed that L296Q mutation was associatedwith CHD with a significantly higher mutant allele frequency in the CHD patients than that in the controls (0.160 vs. 0.091,x2= 9.014, P = 0.003), and that the odds ratio for the development of CHD was 1.83 for the296Q allele carriers relative to 296LL homozygotes. Statistical analyses demonstrated that the mutant 296Q allelecarrier patients displayed significantly higher total cholesterol (TC) and low density lipoprotein cholesterol(LDL-C) concentrations than non-carrier patients. The results of the present study suggest that the L296Qmutation is related to CHD, and the identification of new mutations in the CETP gene will afford the oppor-tunity to investigate the relationship between CETP gene and CHD.

  18. A Missense Mutation in Epsilon-subunit of Acetylcholine Receptor Causing Autosomal Dominant Slow-channel Congenital Myasthenic Syndrome in a Chinese Family

    Institute of Scientific and Technical Information of China (English)

    Jia-Ze Tan; Yuan Man; Fei Xiao

    2016-01-01

    Background:Congenital myasthenic syndromes are a group orrare disorders that are clinically and genetically heterogeneous and caused by mutations in the genes encoding proteins of the neuromuscular junction.Here,we described a Chinese family that presented with phenotypes of classic slow-channel congenital myasthenic syndrome (SCCMS).Methods:Clinical characteristics and electrophysiological features of three patients from a Chinese family were examined,and next-generation sequencing followed by direct sequencing was carried out.Results:The patients revealed variability in clinical and electrophysiological features.However,weakness,scoliosis,and repetitive-compound muscle action potential were found in all affected members in the family.A heterozygous C>T missense mutation at nucleotide 865 in acetylcholine receptor epsilon-subunit (CHRNE) gene that causes a leucine-to-phenylalanine substitution at position 289 (L289F) was found.Conclusions:We reported a SCCMS family of Chinese origin.In the family,classical clinical phenotype with phenotypic variability among different members was found.Genetic testing could help diagnose this rare disease.

  19. A novel missense KIT mutation causing piebaldism in one Chinese family associated with café-au-lait macules and intertriginous freckling

    Directory of Open Access Journals (Sweden)

    Jia WX

    2015-04-01

    Full Text Available Wei-Xue Jia,1,2 Xue-Min Xiao,1,2 Jian-Bing Wu,1,2 Yi-Ping Ma,1,2 Yi-Ping Ge,1,2 Qi Li,1,2 Qiu-Xia Mao,1,2 Cheng-Rang Li1,2 1Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, Jiangsu, China; 2Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, Jiangsu, China Abstract: Piebaldism is a rare autosomal dominant genodermatosis, manifesting as congenital and stable depigmentation of the skin and white forelock. It has been found to be associated with mutations in the KIT or SLUG genes. We report a Chinese piebaldism family including a 28-year-old woman and her 3-year-old son with characteristics of white patches and forelock associated with numerous brown macules and patches. Genomic DNA samples of the proband and her son were extracted from their peripheral blood. One hundred unrelated healthy individuals were used as controls. All coding regions of KIT, SLUG, and NF1 genes were amplified by polymerase chain reaction using exon flanking intronic primers and Sanger sequencings were performed. DNA sequencing revealed heterozygous missense c.2431T>G mutation in exon 17 of the KIT gene in the proband and the affected son. No potentially pathogenic variant was identified in SLUG or NF1 genes. The nucleotide substitution was not found in 100 unrelated control individuals. This study reveals a novel KIT mutation in piebaldism, and it further supports that café-au-lait macules and intertriginous freckling of piebaldism are parts of pigmented anomaly in piebaldism, which does not necessarily represent coexistence of neurofibromatosis type 1 (NF1. Keywords: novel mutation, KIT gene, neurofibromatosis type 1 

  20. Predicting the impact of Lynch syndrome-causing missense mutations from structural calculations

    DEFF Research Database (Denmark)

    Nielsen, Sofie V,; Stein, Amelie; Dinitzen, Alexander B.

    2017-01-01

    Accurate methods to assess the pathogenicity of mutations are needed to fully leverage the possibilities of genome sequencing in diagnosis. Current data-driven and bioinformatics approaches are, however, limited by the large number of new variations found in each newly sequenced genome, and often...... and for diagnosis of Lynch syndrome, and perhaps other hereditary diseases.......Accurate methods to assess the pathogenicity of mutations are needed to fully leverage the possibilities of genome sequencing in diagnosis. Current data-driven and bioinformatics approaches are, however, limited by the large number of new variations found in each newly sequenced genome, and often...... do not provide direct mechanistic insight. Here we demonstrate, for the first time, that saturation mutagenesis, biophysical modeling and co-variation analysis, performed in silico, can predict the abundance, metabolic stability, and function of proteins inside living cells. As a model system, we...

  1. A missense mutation S228P in the CRYBB1 gene causes autosomal dominant congenital cataract

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; MA Xu; GU Feng; LIU Ning-pu; HAO Xiao-lin; WANG Kai-jie; WANG Ning-li; ZHU Si-quan

    2007-01-01

    Background Congenital cataract is a highly heterogeneous disorder at both the genetic and phenotypic levels. This study was conducted to identify disease locus for autosomal dominant congenital cataracts in a four generation Chinese family.Methods Family history and clinical data were recorded. All the members were genotyped with microsatellite markers which are close to the known genetic loci for autosomal congenital cataracts. Two-point Lod scores were obtained using the MLINK of the LINKAGE program package (ver 5.1). Candidate genes were amplified by polymerase chain reaction (PCR) and direct cycle sequencing.Results The maximum Lod score of Zmax=2.11 was obtained with three microsatellite markers D22S258, D22S315,and D22S1163 at recombination fraction θ= 0. Haplotype analysis showed that the disease gene was localized to a 18.5 Mbp region on chromosome 22 flanked by markers D22S1174 and D22S270, spanning the β-crystallin gene cluster. A c.752T-->C mutation in exon 6 of CRYBB1 gene, which resulted in a heterozygous S228P mutation in predicted protein,was found to cosegregate with cataract in the family.Conclusions This study identified a novel mutation in CRYBB1 gene in a Chinese family with autosomal dominant congenital cataract. These results provide strong evidence that CRYBB1 is a pathogenic gene for congenital cataract.

  2. Involvement of ER Stress in Dysmyelination of Pelizaeus-Merzbacher Disease with PLP1 Missense Mutations Shown by iPSC-Derived Oligodendrocytes

    Directory of Open Access Journals (Sweden)

    Yuko Numasawa-Kuroiwa

    2014-05-01

    Full Text Available Pelizaeus-Merzbacher disease (PMD is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1 gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation.

  3. Whole Genome Sequencing Identifies a Missense Mutation in HES7 Associated with Short Tails in Asian Domestic Cats

    Science.gov (United States)

    Xu, Xiao; Sun, Xin; Hu, Xue-Song; Zhuang, Yan; Liu, Yue-Chen; Meng, Hao; Miao, Lin; Yu, He; Luo, Shu-Jin

    2016-01-01

    Domestic cats exhibit abundant variations in tail morphology and serve as an excellent model to study the development and evolution of vertebrate tails. Cats with shortened and kinked tails were first recorded in the Malayan archipelago by Charles Darwin in 1868 and remain quite common today in Southeast and East Asia. To elucidate the genetic basis of short tails in Asian cats, we built a pedigree of 13 cats segregating at the trait with a founder from southern China and performed linkage mapping based on whole genome sequencing data from the pedigree. The short-tailed trait was mapped to a 5.6 Mb region of Chr E1, within which the substitution c. 5T > C in the somite segmentation-related gene HES7 was identified as the causal mutation resulting in a missense change (p.V2A). Validation in 245 unrelated cats confirmed the correlation between HES7-c. 5T > C and Chinese short-tailed feral cats as well as the Japanese Bobtail breed, indicating a common genetic basis of the two. In addition, some of our sampled kinked-tailed cats could not be explained by either HES7 or the Manx-related T-box, suggesting at least three independent events in the evolution of domestic cats giving rise to short-tailed traits. PMID:27560986

  4. Fibrodysplasia ossificans progressiva: middle-age onset of heterotopic ossification from a unique missense mutation (c.974G>C, p.G325A) in ACVR1.

    Science.gov (United States)

    Whyte, Michael P; Wenkert, Deborah; Demertzis, Jennifer L; DiCarlo, Edward F; Westenberg, Erica; Mumm, Steven

    2012-03-01

    Fibrodysplasia ossificans progressiva (FOP) is the rare mendelian disease characterized by congenital malformation of the great toes preceding heterotopic ossification (HO) and caused by heterozygous activating mutation of the ACVR1 gene, which encodes the ALK2 receptor for bone morphogenetic proteins. Early adult life is the latest reported presentation for the HO of FOP. The patient of our report first developed HO from FOP at 47 years of age. She had congenital hallux valgus deformity but despite various traumas was previously well. HO began several months after a brief, seemingly viral, illness. Sudden and progressive pain, redness, warmth, and swelling appeared over a scapula. Computed tomography was remarkable for asymmetrical thickening of muscles and fascial planes. At first, the significance of the great toe abnormalities went unrecognized elsewhere, and biopsy for suspected inflammatory fasciitis revealed proliferating fibroblasts with scattered inflammatory cells. Prednisone improved her symptoms but, when tapered, swellings developed on her chest, posterior thorax, and flank, and FOP was diagnosed. Methylprednisolone, methotrexate, and alendronate seemed to help her symptoms, but the lesions worsened and HO appeared and rapidly progressed. Mutation analysis of the ACVR1 gene revealed heterozygosity for a unique missense defect (c.974G>C, p.G325A) that predicted a conservative (mild) amino acid change within the kinase domain of ALK2. Hence, HO in FOP can be delayed until middle-age, and perhaps provoked by a viral illness. Nevertheless, progression of HO can then be rapid despite bisphosphonate and high-dose immunosuppressive therapy. Possibly, our patient's late-onset HO reflects her mild alteration of ALK2 or some protective and therapeutically useful genetic, epigenetic, or nongenetic factor. Recognition of presymptomatic individuals or late-onset HO in FOP should have these patients avoid traumas, treatments, and maybe viral illnesses that can

  5. The Clinical Spectrum of Missense Mutations of the First Aspartic Acid of cbEGF-like Domains in Fibrillin-1 Including a Recessive Family

    Science.gov (United States)

    Hilhorst-Hofstee, Yvonne; Rijlaarsdam, Marry EB; Scholte, Arthur JHA; Swart-van den Berg, Marietta; Versteegh, Michel IM; van der Schoot-van Velzen, Iris; Schäbitz, Hans-Joachim; Bijlsma, Emilia K; Baars, Marieke J; Kerstjens-Frederikse, Wilhelmina S; Giltay, Jacques C; Hamel, Ben C; Breuning, Martijn H; Pals, Gerard

    2010-01-01

    Marfan syndrome (MFS) is a dominant disorder with a recognizable phenotype. In most patients with the classical phenotype mutations are found in the fibrillin-1 gene (FBN1) on chromosome 15q21. It is thought that most mutations act in a dominant negative way or through haploinsufficiency. In 9 index cases referred for MFS we detected heterozygous missense mutations in FBN1 predicted to substitute the first aspartic acid of different calcium-binding Epidermal Growth Factor-like (cbEGF) fibrillin-1 domains. A similar mutation was found in homozygous state in 3 cases in a large consanguineous family. Heterozygous carriers of this mutation had no major skeletal, cardiovascular or ophthalmological features of MFS. In the literature 14 other heterozygous missense mutations are described leading to the substitution of the first aspartic acid of a cbEGF domain and resulting in a Marfan phenotype. Our data show that the phenotypic effect of aspartic acid substitutions in the first position of a cbEGF domain can range from asymptomatic to a severe neonatal phenotype. The recessive nature with reduced expression of FBN1 in one of the families suggests a threshold model combined with a mild functional defect of this specific mutation. © 2010 Wiley-Liss, Inc. PMID:20886638

  6. Missense Mutation in Fam83H Gene in Iranian Patients with Amelogenesis Imperfecta.

    Directory of Open Access Journals (Sweden)

    S Jalal Pourhashemi

    2014-12-01

    Full Text Available Amelogenesis Imperfecta (AI is a disorder of tooth development where there is an abnormal formation of enamel or the external layer of teeth. The aim of this study was to screen mutations in the four most important candidate genes, ENAM, KLK4, MMP20 and FAM83H responsible for amelogenesis imperfect.Geneomic DNA was isolated from five Iranian families with 22 members affected with enamel malformations. The PCR amplifications were typically carried out for amplification the coding regions for AI patients and unaffected family members. The PCR products were subjected to direct sequencing. The pedigree analysis was performed using Cyrillic software.One family had four affected members with autosomal dominant hypocalcified amelogenesis imperfecta (ADHPCAI; pedigree analysis revealed four consanguineous families with 18 patients with autosomal recessive hypoplastic amelogenesis imperfecta (ARHPAI. One non-synonymous single-nucleotide substitution, c.1150T>A, p. Ser 342Thr was identified in the FAM83H, which resulted in ADHCAI. Furthermore, different polymorphisms or unclassified variants were detected in MMP20, ENAM and KLK4.Our results are consistent with other studies and provide further evidence for pathogenic mutations of FAM83H gene. These findings suggest different loci and genes could be implicated in the pathogenesis of AI.

  7. Erythrocytic Iron Deficiency Enhances Susceptibility to Plasmodium chabaudi Infection in Mice Carrying a Missense Mutation in Transferrin Receptor 1.

    Science.gov (United States)

    Lelliott, Patrick M; McMorran, Brendan J; Foote, Simon J; Burgio, Gaetan

    2015-11-01

    The treatment of iron deficiency in areas of high malaria transmission is complicated by evidence which suggests that iron deficiency anemia protects against malaria, while iron supplementation increases malaria risk. Iron deficiency anemia results in an array of pathologies, including reduced systemic iron bioavailability and abnormal erythrocyte physiology; however, the mechanisms by which these pathologies influence malaria infection are not well defined. In the present study, the response to malaria infection was examined in a mutant mouse line, Tfrc(MRI24910), identified during an N-ethyl-N-nitrosourea (ENU) screen. This line carries a missense mutation in the gene for transferrin receptor 1 (TFR1). Heterozygous mice exhibited reduced erythrocyte volume and density, a phenotype consistent with dietary iron deficiency anemia. However, unlike the case in dietary deficiency, the erythrocyte half-life, mean corpuscular hemoglobin concentration, and intraerythrocytic ferritin content were unchanged. Systemic iron bioavailability was also unchanged, indicating that this mutation results in erythrocytic iron deficiency without significantly altering overall iron homeostasis. When infected with the rodent malaria parasite Plasmodium chabaudi adami, mice displayed increased parasitemia and succumbed to infection more quickly than their wild-type littermates. Transfusion of fluorescently labeled erythrocytes into malaria parasite-infected mice demonstrated an erythrocyte-autonomous enhanced survival of parasites within mutant erythrocytes. Together, these results indicate that TFR1 deficiency alters erythrocyte physiology in a way that is similar to dietary iron deficiency anemia, albeit to a lesser degree, and that this promotes intraerythrocytic parasite survival and an increased susceptibility to malaria in mice. These findings may have implications for the management of iron deficiency in the context of malaria.

  8. Molecular genetic and functional association of Brugada and early repolarization syndromes with S422L missense mutation in KCNJ8.

    Science.gov (United States)

    Barajas-Martínez, Hector; Hu, Dan; Ferrer, Tania; Onetti, Carlos G; Wu, Yuesheng; Burashnikov, Elena; Boyle, Madalene; Surman, Tyler; Urrutia, Janire; Veltmann, Christian; Schimpf, Rainer; Borggrefe, Martin; Wolpert, Christian; Ibrahim, Bassiema B; Sánchez-Chapula, José Antonio; Winters, Stephen; Haïssaguerre, Michel; Antzelevitch, Charles

    2012-04-01

    Adenosine triphosphate (ATP)-sensitive potassium cardiac channels consist of inward-rectifying channel subunits Kir6.1 or Kir6.2 (encoded by KCNJ8 or KCNJ11) and the sulfonylurea receptor subunits SUR2A (encoded by ABCC9). To examine the association of mutations in KCNJ8 with Brugada syndrome (BrS) and early repolarization syndrome (ERS) and to elucidate the mechanism underlying the gain of function of ATP-sensitive potassium channel current. Direct sequencing of KCNJ8 and other candidate genes was performed on 204 BrS and ERS probands and family members. Whole-cell and inside-out patch-clamp methods were used to study mutated channels expressed in TSA201 cells. The same missense mutation, p.Ser422Leu (c.1265C>T) in KCNJ8, was identified in 3 BrS and 1 ERS probands but was absent in 430 alleles from ethnically matched healthy controls. Additional genetic variants included CACNB2b-D601E. Whole-cell patch-clamp studies showed a 2-fold gain of function of glibenclamide-sensitive ATP-sensitive potassium channel current when KCNJ8-S422L was coexpressed with SUR2A-wild type. Inside-out patch-clamp evaluation yielded a significantly greater half maximal inhibitory concentration for ATP in the mutant channels (785.5 ± 2 vs 38.4 ± 3 μM; n = 5; P <.01), pointing to incomplete closing of the ATP-sensitive potassium channels under normoxic conditions. Patients with a CACNB2b-D601E polymorphism displayed longer QT/corrected QT intervals, likely owing to their effect to induce an increase in L-type calcium channel current (I(Ca-L)). Our results support the hypothesis that KCNJ8 is a susceptibility gene for BrS and ERS and point to S422L as a possible hotspot mutation. Our findings suggest that the S422L-induced gain of function in ATP-sensitive potassium channel current is due to reduced sensitivity to intracellular ATP. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  9. Identification of a missense mutation and several polymorphisms in the proenkephalin A gene of schizophrenic patients

    Energy Technology Data Exchange (ETDEWEB)

    Mikesell, M.J.; Sommer, S.S.; McMurray, C.T. [Mayo Foundation and Mayo Graduate School, Rochester, MN (United States)] [and others

    1996-09-20

    Schizophrenia is a complex and severe disorder of unknown cause and pathophysiology. In this study, we examined the opioid hypothesis for schizophrenia at the molecular level, focusing on the dopamine-regulated proenkephalin A gene (chromosome 8q11.23-q12). We have screened 150 schizophrenic patients for sequence variations within the promoter region, entire coding sequence, and 3{prime}-untranslated region. We find one sequence change in a conserved amino acid that may be of functional significance. This mutation was found in a single schizophrenia patient but not in controls. Although several new, race-specific polymorphisms were identified, all other sequence changes appeared to be common polymorphisms, unlikely to contribute to the etiology of schizophrenia. 38 refs., 3 figs., 2 tabs.

  10. Missense mutation R338W in ARHGEF9 in a family with X-linked intellectual disability with variable macrocephaly and macro-orchidism

    Directory of Open Access Journals (Sweden)

    Philip eLong

    2016-01-01

    Full Text Available Non-syndromal X-linked intellectual disability (NS-XLID represents a broad group of clinical disorders in which ID is the only clinically consistent manifestation. Although in many cases either chromosomal linkage data or knowledge of the >100 existing XLID genes has assisted mutation discovery, the underlying cause of disease remains unresolved in many families. We report the resolution of a large family (K8010 with NS-XLID, with variable macrocephaly and macro-orchidism. Although a previous linkage study had mapped the locus to Xq12-q21, this region contained too many candidate genes to be analyzed using conventional approaches. However, X-chromosome exome sequencing, bioinformatics analysis and segregation analysis revealed a novel missense mutation (c.1012C>T; p.R338W in ARHGEF9. This gene encodes collybistin, a neuronal GDP-GTP exchange factor previously implicated in several cases of XLID, as well as clustering of gephyrin and GABAA receptors at inhibitory synapses. Molecular modeling of the collybistin R338W substitution revealed that this change results in the substitution of a long electropositive side-chain with a large non-charged hydrophobic side-chain. The R338W change is predicted to result in clashes with adjacent amino acids (K363 and D335 and disruption of electrostatic potential and local folding of the PH domain, which is known to bind phosphatidylinositol-3-phosphate (PI3P/PtdIns-3-P. Consistent with this finding, functional assays revealed that recombinant collybistin CB2SH3-R338W was deficient in PI3P binding and was not able to translocate EGFP-gephyrin to submembrane microaggregates in an in vitro clustering assay. Taken together, these results suggest that the R338W mutation in ARHGEF9 is the underlying cause of NS-XLID in this family.

  11. A missense mutation in the 3-ketodihydrosphingosine reductase FVT1 as candidate causal mutation for bovine spinal muscular atrophy

    OpenAIRE

    Krebs, Stefan; Medugorac, Ivica; Röther, Susanne; Strässer, Katja; Förster, Martin

    2007-01-01

    The bovine form of the autosomal recessive neurodegenerative disease spinal muscular atrophy (SMA) shows striking similarity to the human form of the disease. It has, however, been mapped to a genomic region not harboring the bovine orthologue of the SMN gene, mutation of which causes human SMA. After refinement of the mapping results we analyzed positional and functional candidate genes. One of three candidate genes, FVT1, encoding 3-ketodihydrosphingosine reductase, which catalyzes a crucia...

  12. A missense mutation in CHS1, a TIR-NB protein, induces chilling sensitivity in Arabidopsis.

    Science.gov (United States)

    Wang, Yuancong; Zhang, Yao; Wang, Zheng; Zhang, Xiaoyan; Yang, Shuhua

    2013-08-01

    Low temperature is an environmental factor that affects plant growth and development and plant-pathogen interactions. How temperature regulates plant defense responses is not well understood. In this study, we characterized chilling-sensitive mutant 1 (chs1), and functionally analyzed the role of the CHS1 gene in plant responses to chilling stress. The chs1 mutant displayed a chilling-sensitive phenotype, and also displayed defense-associated phenotypes, including extensive cell death, the accumulation of hydrogen peroxide and salicylic acid, and an increased expression of PR genes: these phenotypes indicated that the mutation in chs1 activates the defense responses under chilling stress. A map-based cloning analysis revealed that CHS1 encodes a TIR-NB-type protein. The chilling sensitivity of chs1 was fully rescued by pad4 and eds1, but not by ndr1. The overexpression of the TIR and NB domains can suppress the chs1-conferred phenotypes. Interestingly, the stability of the CHS1 protein was positively regulated by low temperatures independently of the 26S proteasome pathway. This study revealed the role of a TIR-NB-type gene in plant growth and cell death under chilling stress, and suggests that temperature modulates the stability of the TIR-NB protein in Arabidopsis.

  13. Massively Parallel Sequencing of a Chinese Family with DFNA9 Identified a Novel Missense Mutation in the LCCL Domain of COCH

    Directory of Open Access Journals (Sweden)

    Xiaodong Gu

    2016-01-01

    Full Text Available DFNA9 is a late-onset, progressive, autosomal dominantly inherited sensorineural hearing loss with vestibular dysfunction, which is caused by mutations in the COCH (coagulation factor C homology gene. In this study, we investigated a Chinese family segregating autosomal dominant nonsyndromic sensorineural hearing loss. We identified a missense mutation c.T275A p.V92D in the LCCL domain of COCH cosegregating with the disease and absent in 100 normal hearing controls. This mutation leads to substitution of the hydrophobic valine to an acidic amino acid aspartic acid. Our data enriched the mutation spectrum of DFNA9 and implied the importance for mutation screening of COCH in age related hearing loss with vestibular dysfunctions.

  14. Restoring expression of wild-type p53 suppresses tumor growth but does not cause tumor regression in mice with a p53 missense mutation

    OpenAIRE

    2011-01-01

    The transcription factor p53 is a tumor suppressor. As such, the P53 gene is frequently altered in human cancers. However, over 80% of the P53 mutations found in human cancers are missense mutations that lead to expression of mutant proteins that not only lack p53 transcriptional activity but exhibit new functions as well. Recent studies show that restoration of p53 expression leads to tumor regression in mice carrying p53 deletions. However, the therapeutic efficacy of restoring p53 expressi...

  15. The congenital "ant-egg" cataract phenotype is caused by a missense mutation in connexin46

    DEFF Research Database (Denmark)

    Hansen, Lars; Yao, Wenliang; Eiberg, Hans;

    2006-01-01

    "Ant-egg" cataract is a rare, distinct variety of congenital/infantile cataract that was reported in a large Danish family in 1967. This cataract phenotype is characterized by ant-egg-like bodies embedded in the lens in a laminar configuration and is inherited as an autosomal dominant trait. We...

  16. Missense mutation in CAPN1 is associated with spinocerebellar ataxia in the Parson Russell Terrier dog breed.

    Directory of Open Access Journals (Sweden)

    Oliver P Forman

    Full Text Available Spinocerebellar ataxia (SCA in the Parson Russell Terrier (PRT dog breed is a disease of progressive incoordination of gait and loss of balance. Clinical signs usually become notable between 6 and 12 months of age with affected dogs presenting with symmetric spinocerebellar ataxia particularly evident in the pelvic limbs. The degree of truncal ataxia, pelvic limb hypermetria and impaired balance is progressive, particularly during the initial months of disease. A certain degree of stabilisation as well as intermittent worsening may occur. At the later stages of the disease ambulation often becomes difficult, with owners often electing to euthanise affected dogs on welfare grounds. Using a GWAS approach and target-enriched massively-parallel sequencing, a strongly associated non-synonymous SNP in the CAPN1 gene, encoding the calcium dependent cysteine protease calpain1 (mu-calpain, was identified. The SNP is a missense mutation causing a cysteine to tyrosine substitution at residue 115 of the CAPN1 protein. Cysteine 115 is a highly conserved residue and forms a key part of a catalytic triad of amino acids that are crucial to the enzymatic activity of cysteine proteases. The CAPN1 gene shows high levels of expression in the brain and nervous system and roles for the protein in both neuronal necrosis and maintenance have been suggested. Given the functional implications and high level of conservation observed across species, the CAPN1 variant represents a provocative candidate for the cause of SCA in the PRT and a novel potential cause of ataxia in humans.

  17. Clinical and molecular analysis of a Chinese family with autosomal dominant neurohypophyseal diabetes insipidus associated with a novel missense mutation in the vasopressin-neurophysin II gene.

    Science.gov (United States)

    Luo, Yongfeng; Wang, Binbin; Qiu, Yu; Zhang, Chuan; Jin, Chengluo; Zhao, Yakun; Zhu, Qingguo; Ma, Xu

    2012-08-01

    The objective of this study is to identify the genetic defects in a Chinese family with autosomal dominant familial neurohypophyseal diabetes insipidus. Complete physical examination, fluid deprivation, and DDAVP tests were performed in three affected and three healthy members of the family. Genomic DNA was extracted from leukocytes of venous blood of these individuals for polymerase chain reaction amplification and direct sequencing of all three coding exons of arginine vasopressin-neurophysin II (AVP-NPII) gene. Seven members of this family were suspected to have symptomatic vasopressin-deficient diabetes insipidus. The water deprivation test in all the patients confirmed the diagnosis of vasopressin-deficient diabetes insipidus, with the pedigree demonstrating an autosomal dominant inheritance. Direct sequence analysis revealed a novel mutation (c.193T>A) and a synonymous mutation (c.192C>A) in the AVP-NPII gene. The missense mutation resulted in the substitution of cysteine by serine at a highly conserved codon 65 of exon 2 of the AVP-NPII gene in all affected individuals, but not in unaffected members. We concluded that a novel missense mutation in the AVP-NPII gene caused neurohypophyseal diabetes insipidus in this family, due to impaired neurophysin function as a carrier protein for AVP. The Cys65 is essential for NPII in the formation of a salt bridge with AVP. Presence of this mutation suggests that the portion of the neurophysin peptide encoded by this sequence is important for the normal expression of vasopressin.

  18. Linkage disequilibrium analysis reveals an albuminuria risk haplotype containing three missense mutations in the cubilin gene with striking differences among European and African ancestry populations

    Directory of Open Access Journals (Sweden)

    Tzur Shay

    2012-10-01

    Full Text Available Abstract Background A recent meta-analysis described a variant (p.Ile2984Val in the cubilin gene (CUBN that is associated with levels of albuminuria in the general population and in diabetics. Methods We implemented a Linkage Disequilibrium (LD search with data from the 1000 Genomes Project, on African and European population genomic sequences. Results We found that the p.Ile2984Val variation is part of a larger haplotype in European populations and it is almost absent in west Africans. This haplotype contains 19 single nucleotide polymorphisms (SNPs in very high LD, three of which are missense mutations (p.Leu2153Phe, p.Ile2984Val, p.Glu3002Gly, and two have not been previously reported. Notably, this European haplotype is absent in west African populations, and the frequency of each individual polymorphism differs significantly in Africans. Conclusions Genotyping of these variants in existing African origin sample sets coupled to measurements of urine albumin excretion levels should reveal which is the most likely functional candidate for albuminuria risk. The unique haplotypic structure of CUBN in different populations may leverage the effort to identify the functional variant and to shed light on evolution of the CUBN gene locus.

  19. NROB1基因错义突变致新生儿先天性肾上腺发育不良1例报告%The NROB 1 gene missense mutation causes congenital adrenal dysplasia:a case report

    Institute of Scientific and Technical Information of China (English)

    刘晓景; 杨海花; 李春枝; 陈永兴; 卫海燕

    2016-01-01

    目的:探讨X连锁先天性肾上腺发育不良(AHC)的临床特点及诊断。方法回顾性分析1例AHC患儿的临床资料及基因检测结果,并复习相关文献。结果2个月男性患儿,生后即出现体质量不增伴呕吐,伴有肾上腺功能不全失盐危象。基因检测发现NROB 1基因错义突变,确诊为X-连锁先天性肾上腺发育不良。结论 X连锁先天性肾上腺发育不良是一种罕见病,诊断主要是通过临床表现、实验室检测及NROB 1基因检测。%Objective To explore the clinical feature and diagnosis of the X linked adrenal hypoplasia congenital (X-AHC). Methods The clinical data and gene detection results of one case of AHC were retrospectively analyzed. The related literatures were reviewed. Results Two-month-old male infant was suffered with slow weight gain, vomiting, and salt craving of adrenal insufifciency after birth. Gene detection found a new missense mutation on NROB 1 gene. The diagnosis of X-AHC was conifrmed. Conclusions X-AHC is a kind of rare disease and is diagnosed by clinical manifestation, laboratory testing, and NROB 1 gene detection.

  20. CACNA1H missense mutations associated with amyotrophic lateral sclerosis alter Cav3.2 T-type calcium channel activity and reticular thalamic neuron firing.

    Science.gov (United States)

    Rzhepetskyy, Yuriy; Lazniewska, Joanna; Blesneac, Iulia; Pamphlett, Roger; Weiss, Norbert

    2016-11-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. In a recent study by Steinberg and colleagues, 2 recessive missense mutations were identified in the Cav3.2 T-type calcium channel gene (CACNA1H), in a family with an affected proband (early onset, long duration ALS) and 2 unaffected parents. We have introduced and functionally characterized these mutations using transiently expressed human Cav3.2 channels in tsA-201 cells. Both of these mutations produced mild but significant changes on T-type channel activity that are consistent with a loss of channel function. Computer modeling in thalamic reticular neurons suggested that these mutations result in decreased neuronal excitability of thalamic structures. Taken together, these findings implicate CACNA1H as a susceptibility gene in amyotrophic lateral sclerosis.

  1. A hyperexcitability phenotype in mouse trigeminal sensory neurons expressing the R192Q Cacna1a missense mutation of familial hemiplegic migraine type-1.

    Science.gov (United States)

    Hullugundi, S K; Ansuini, A; Ferrari, M D; van den Maagdenberg, A M J M; Nistri, A

    2014-04-25

    Missense mutation R192Q in the CACNA1A gene causes familial hemiplegic migraine type-1 (FHM1), a monogenic subtype of migraine with aura. Using knock-in (KI) gene targeting we introduced this mutation into the mouse gene and generated a transgenic mouse model to investigate basic mechanisms of migraine pathophysiology. While FHM1 R192Q KI trigeminal ganglia were previously shown to exhibit constitutive up-regulation of ATP-gated P2X3 receptors, little is known about the firing properties of trigeminal sensory neurons, which convey nociceptive inputs to higher brain centers. We patch-clamped trigeminal sensory neurons to search for differences in firing properties between wildtype (WT) and KI cells in culture. Although various subclasses of trigeminal neurons were observed with respect to their firing patterns evoked by intracellular current injection, their distribution among WT and KI cells was similar with only small differences in rheobase or input resistance values. However, when neurons were excited by either α,β-methyl-ATP to stimulate P2X3 receptors or capsaicin to activate transient receptor potential vanilloid (TRPV1) receptors, the firing threshold in KI neurons was significantly lowered and followed by a larger number of spikes. Activation by α,β-methyl-ATP was associated with a transient cluster of action potentials, while capsaicin elicited more persistent firing. Using α,β-methyl-ATP or capsaicin, two functional classes of WT or KI neurons were distinguished according to the first spike latency, which suggests that a subgroup of neurons may be indirectly activated, probably via crosstalk between neurons and satellite glial cells. Thus, our results are consistent with reported facilitated trigeminal pain behavior of FHM1 R192Q KI mice. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. Evidence for selection against human lung cancers bearing p53 missense mutations which occur within the HLA A*0201 peptide consensus motif.

    Science.gov (United States)

    Wiedenfeld, E A; Fernandez-Viña, M; Berzofsky, J A; Carbone, D P

    1994-03-01

    Short peptide fragments of intracellular proteins that fit a defined sequence motif bind to the most common human major histocompatibility complex class I molecule, HLA A*0201, and mediate killing by cytotoxic T-cells [D.F. Hunt et al., Science (Washington DC), 255: 1261-1263, 1992; K. Falk et al., Nature (Lond.), 351: 290-296, 1991]. The existence of such a motif allows prediction of whether novel peptides derived from mutant oncoporteins might be presented on the surface of cancer cells bearing that HLA allele. Clinical cancer might develop only when these mutations occur outside a major histocompatibility complex binding motif or in those cells that acquire defects in antigen presentation. Here, we find that missense mutations of p53 from a variety of tumors fall within the HLA A*0201 motif less often than would be expected if the location of mutations and motifs were independent. When we analyzed the HLA subtype of lung cancer cell lines with known p53 missense mutations, we found that all of the mutant oncopeptides predicted to be presentable by HLA A*0201 came from tumors that either did not carry the A*0201 allele or had lost that allele in the process of tumorigenesis. Presentation of mutant oncogene peptides on class I major histocompatibility complex might thus represent a physiologically significant selection pressure in the development of human cancer.

  3. The Large Phenotypic Spectrum of Fabry Disease Requires Graduated Diagnosis and Personalized Therapy: A Meta-Analysis Can Help to Differentiate Missense Mutations

    Directory of Open Access Journals (Sweden)

    Valentina Citro

    2016-12-01

    Full Text Available Fabry disease is caused by mutations in the GLA gene and is characterized by a large genotypic and phenotypic spectrum. Missense mutations pose a special problem for graduating diagnosis and choosing a cost-effective therapy. Some mutants retain enzymatic activity, but are less stable than the wild type protein. These mutants can be stabilized by small molecules which are defined as pharmacological chaperones. The first chaperone to reach clinical trial is 1-deoxygalactonojirimycin, but others have been tested in vitro. Residual activity of GLA mutants has been measured in the presence or absence of pharmacological chaperones by several authors. Data obtained from transfected cells correlate with those obtained in cells derived from patients, regardless of whether 1-deoxygalactonojirimycin was present or not. The extent to which missense mutations respond to 1-deoxygalactonojirimycin is variable and a reference table of the results obtained by independent groups that is provided with this paper can facilitate the choice of eligible patients. A review of other pharmacological chaperones is provided as well. Frequent mutations can have residual activity as low as one-fourth of normal enzyme in vitro. The reference table with residual activity of the mutants facilitates the identification of non-pathological variants.

  4. The Large Phenotypic Spectrum of Fabry Disease Requires Graduated Diagnosis and Personalized Therapy: A Meta-Analysis Can Help to Differentiate Missense Mutations

    Science.gov (United States)

    Citro, Valentina; Cammisa, Marco; Liguori, Ludovica; Cimmaruta, Chiara; Lukas, Jan; Cubellis, Maria Vittoria; Andreotti, Giuseppina

    2016-01-01

    Fabry disease is caused by mutations in the GLA gene and is characterized by a large genotypic and phenotypic spectrum. Missense mutations pose a special problem for graduating diagnosis and choosing a cost-effective therapy. Some mutants retain enzymatic activity, but are less stable than the wild type protein. These mutants can be stabilized by small molecules which are defined as pharmacological chaperones. The first chaperone to reach clinical trial is 1-deoxygalactonojirimycin, but others have been tested in vitro. Residual activity of GLA mutants has been measured in the presence or absence of pharmacological chaperones by several authors. Data obtained from transfected cells correlate with those obtained in cells derived from patients, regardless of whether 1-deoxygalactonojirimycin was present or not. The extent to which missense mutations respond to 1-deoxygalactonojirimycin is variable and a reference table of the results obtained by independent groups that is provided with this paper can facilitate the choice of eligible patients. A review of other pharmacological chaperones is provided as well. Frequent mutations can have residual activity as low as one-fourth of normal enzyme in vitro. The reference table with residual activity of the mutants facilitates the identification of non-pathological variants. PMID:27916943

  5. A missense mutation in ALDH1A3 causes isolated microphthalmia/anophthalmia in nine individuals from an inbred Muslim kindred.

    Science.gov (United States)

    Mory, Adi; Ruiz, Francesc X; Dagan, Efrat; Yakovtseva, Evgenia A; Kurolap, Alina; Parés, Xavier; Farrés, Jaume; Gershoni-Baruch, Ruth

    2014-03-01

    Nine affected individuals with isolated anophthalmia/microphthalmia from a large Muslim-inbred kindred were investigated. Assuming autosomal-recessive mode of inheritance, whole-genome linkage analysis, on DNA samples from four affected individuals, was undertaken. Homozygosity mapping techniques were employed and a 1.5-Mbp region, homozygous in all affected individuals, was delineated. The region contained nine genes, one of which, aldehyde dehydrogenase 1 (ALDH1A3), was a clear candidate. This gene seems to encode a key enzyme in the formation of a retinoic-acid gradient along the dorsoventral axis during an early eye development and the development of the olfactory system. Sanger sequence analysis revealed a missense mutation, causing a substitution of valine (Val) to methionine (Met) at position 71. Analyzing the p.Val71Met missense mutation using standard open access software (MutationTaster online, PolyPhen, SIFT/PROVEAN) predicts this variant to be damaging. Enzymatic activity, studied in vitro, showed no changes between the mutated and the wild-type ALDH1A3 protein.

  6. A novel missense mutation in CACNA1A evaluated by in silico protein modeling is associated with non-episodic spinocerebellar ataxia with slow progression.

    Science.gov (United States)

    Bürk, Katrin; Kaiser, Frank J; Tennstedt, Stephanie; Schöls, Ludger; Kreuz, Friedmar R; Wieland, Thomas; Strom, Tim M; Büttner, Thomas; Hollstein, Ronja; Braunholz, Diana; Plaschke, Jens; Gillessen-Kaesbach, Gabriele; Zühlke, Christine

    2014-04-01

    Spinocerebellar ataxia type 6 (SCA6), episodic ataxia type 2 (EA2) and familial hemiplegic migraine type 1 (FHM1) are allelic disorders of the gene CACNA1A encoding the P/Q subunit of a voltage gated calcium channel. While SCA6 is related to repeat expansions affecting the C-terminal part of the protein, EA2 and FHM phenotypes are usually associated with nonsense and missense mutations leading to impaired channel properties. In three unrelated families with dominant cerebellar ataxia, symptoms cosegregated with CACNA1A missense mutations of evolutionary highly conserved amino acids (exchanges p.E668K, p.R583Q and p.D302N). To evaluate pathogenic effects, in silico, protein modeling analyses were performed which indicate structural alterations of the novel mutation p.E668K within the homologous domain 2 affecting CACNA1A protein function. The phenotype is characterised by a very slowly progressive ataxia, while ataxic episodes or migraine are uncommon. These findings enlarge the phenotypic spectrum of CACNA1A mutations. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  7. Cerebellar ataxia, hemiplegic migraine, and related phenotypes due to a CACNA1A missense mutation: 12-year follow-up of a large Portuguese family.

    Science.gov (United States)

    Barros, José; Damásio, Joana; Tuna, Assunção; Alves, Ivânia; Silveira, Isabel; Pereira-Monteiro, José; Sequeiros, Jorge; Alonso, Isabel; Sousa, Alda; Coutinho, Paula

    2013-02-01

    To document and discuss the broad phenotypic variability in a Portuguese family with cerebellar ataxia, hemiplegic migraine, and related syndromes caused by missense mutation c.1748 (p.R583Q) in the CACNA1A gene. Observational 12-year follow-up study. Community and hospital care. Sixteen patients in a 4-generation family were identified in 1998 in a population-based survey. The follow-up revealed 28 patients (25 of whom were observed) and 32 unaffected relatives with an a priori risk of 50%. Four major phenotypes (migraine with multiple auras, transient focal neurological deficits without headache, coma triggered by minor head trauma, and slowly progressive cerebellar ataxia) were present in various combinations. The initial manifestation was ataxia in 16 patients and a transient episode in 12 patients. Eighteen patients did not have migraine, and 11 showed only ataxia. The c.1748 (p.R583Q) mutation in CACNA1A was confirmed in all 23 of the patients who were tested but was not found in any of the 27 adult relatives. The CACNA1A CAG repeat expansion was excluded. A unique missense mutation in the CACNA1A gene, which exhibits a very high penetrance and expressivity, may present a phenotypic spectrum that is broader than current descriptions. Single-gene disorders can behave as complex traits, which reinforces the importance of genetic modifiers in the tightly regulated function of P/Q-type calcium channels. The clinical spectrum of missense mutation CACNA1A -related disorders is much broader than strictly familial hemiplegic migraine.

  8. De novo exon 1 missense mutations of SKI and Shprintzen-Goldberg syndrome: two new cases and a clinical review.

    Science.gov (United States)

    Au, P Y Billie; Racher, Hilary E; Graham, John M; Kramer, Nancy; Lowry, R Brian; Parboosingh, Jillian S; Innes, A Micheil

    2014-03-01

    Shprintzen-Goldberg syndrome (OMIM #182212) is a connective tissue disorder characterized by craniosynostosis, distinctive craniofacial features, skeletal abnormalities, marfanoid body habitus, aortic dilatation, and intellectual disability. Mutations in exon 1 of SKI have recently been identified as being responsible for approximately 90% of reported individuals diagnosed clinically with Shprintzen-Goldberg syndrome. SKI is a known regulator of TGFβ signaling. Therefore, like Marfan syndrome and Loeys-Dietz syndrome, Shprintzen-Goldberg syndrome is likely caused by deregulated TGFβ signals, explaining the considerable phenotypic overlap between these three disorders. We describe two additional patients with exon 1 SKI mutations and review the clinical features and literature of Shprintzen-Goldberg syndrome.

  9. Variants of the D{sub 5} dopamine receptor gene found in patients with schizophrenia: Identification of a nonsense mutation and multiple missense changes

    Energy Technology Data Exchange (ETDEWEB)

    Sobell, J.L.; Lind, T.J.; Sommer, S.S. [Mayo Clinic/Foundation, Rochester, MN (United States)] [and others

    1994-09-01

    To determine whether mutations in the D{sub 5} dopamine receptor (D{sub 5}DR) gene are associated with schizophrenia, the gene was examined in 78 unrelated schizophrenic individuals. After amplification by the polymerase chain reaction, products were examined by dideoxy fingerprinting (ddF), a highly sensitive screening method related to single strand conformational polymorphism analysis. All samples with unusual ddF patterns were sequenced to precisely identify the sequence change. In the 156 D{sub 5}DR alleles examined, nine sequence changes were identified. Four of the nine did not affect protein structure; of these, three were silent changes and one was a transition in the 3{prime} untranslated region. The remaining five sequence changes result in protein alterations: of these, one is a missense change in a non-conserved amino acid, 3 are missense changes in amino acids that are conserved in some dopamine D{sub 5} receptors and the last is a nonsense mutation. To investigate whether the nonsense mutation was associated with schizophrenia, 400 additional schizophrenic cases of western European descent and 1914 ethnically-similar controls were screened for the change. One additional schizophrenic carrier was identified and verified by direct genomic sequencing (allele frequency: .0013), but eight carriers also were found and confirmed among the non-schizophrenics (allele frequency: .0021)(p>.25). The gene was re-examined in all newly identified carriers of the nonsense mutation by direct sequencing and/or ddF in search of additional mutations. None were identified. Family studies also were conducted to investigate possible cosegregation of the mutation with other neuropsychiatric diseases, but this was not demonstrated. Thus, the mutation does not appear to be associated with an increased risk of schizophrenia nor does an initial analysis suggest cosegregation with other neuropsychiatric disorders or symptom complexes.

  10. Hereditary otovestibular dysfunction and Ménière's disease in a large Belgian family is caused by a missense mutation in the COCH gene.

    Science.gov (United States)

    Verstreken, M; Declau, F; Wuyts, F L; D'Haese, P; Van Camp, G; Fransen, E; Van den Hauwe, L; Buyle, S; Smets, R E; Feenstra, L; Van der Stappen, A; Van de Heyning, P H

    2001-11-01

    To report the clinical, auditory, and vestibular characteristics of a nonsyndromic otovestibular dysfunction in a large Belgian family caused by a missense mutation of the DFNA9 gene: COCH. Retrospective study of the clinical, audiologic, and vestibular data of 60 genetically affected cases. Tertiary referral center. All members of a Belgian kindred who carry the genetic (P51S) defect linked to the inherited hearing and vestibular impairment. Diagnostic otologic, audiometric, and vestibular analysis and imaging. Pure tone audiometry, supraliminary audiometry. and vestibular investigation. The autosomal dominant inherited impairment was characterized by peripheral degeneration of the inner ear, leading to total deafness and bilateral vestibular areflexia. The genetically affected persons of a Belgian family shared a progressive sensorineural hearing loss starting between the third and sixth decade. Vestibular symptoms started at about the same age as the hearing loss. The vestibular symptoms consisted of instability in darkness, a tendency to fall sideways, light-headiness, a drunken feeling, and attacks of vertigo. Most of the patients reported tinnitus, and half of them reported pressure in the ears. Clinically, 9 of the 60 patients met the criteria for definite Ménière's disease, and another 13 and 17 patients met the criteria for probable or possible Ménière's disease, respectively. All 9 were older than the age of 35, but only 1 was older than 55 years, so more than 30% of the patients were between 35 and 55 years old. A specific pattern could be recognized in the evolution of the otovestibular impairment. Under the age of 35 years, almost all the affected family members had normal hearing, whereas above the age of 55 years, the hearing loss was at least moderate, and vestibular hypofunction occurred. In between, there was a transition period of two to three decades, when deterioration of the cochleovestibular function occurred, with a temporary audiometric

  11. A missense mutation in MKRN3 in a Danish girl with central precocious puberty and her brother with early puberty

    DEFF Research Database (Denmark)

    Känsäkoski, Johanna; Raivio, Taneli; Juul, Anders

    2015-01-01

    BACKGROUND: Idiopathic central precocious puberty (ICPP) results from the premature reactivation of the hypothalamic-pituitary-gonadal axis leading to development of secondary sexual characteristics prior to 8 y in girls or 9 y in boys. Since the initial discovery of mutations in the maternally...... hypothalamic complementary DNA (cDNA) was investigated by PCR. RESULTS: One paternally inherited rare variant, c.1034G>A (p.Arg345His), was identified in one girl with ICPP and in her brother with early puberty. The variant is predicted to be deleterious by three different in silico prediction programs....... Expression of MKRN3 was confirmed in adult human hypothalamus. CONCLUSION: Our results are in line with previous studies in which paternally inherited MKRN3 mutations have been found both in males and in females with ICPP or early puberty. Our report further expands the set of MKRN3 mutations identified...

  12. A missense mutation in the cystathionine {beta}-synthase (CBS) gene associated with pyridoxine (B{sub 6}) responsive homocystinuria

    Energy Technology Data Exchange (ETDEWEB)

    Shih, V.E.; Fringer, J.M.; Mandell, R. [Massachusetts General Hospital, Boston, MA (United States)] [and others

    1994-09-01

    CBS deficiency is an autosomal recessive disorder characterized by homocystinuria and multisystem clinical disease. B{sub 6} responsive patients usually have a milder clinical phenotype than B{sub 6} nonresponsive patients. In our ongoing studies of the molecular defects in CBS deficiency, we reported a T-833 to C transition causing a substitution of threonine for isoleucine at position 278 (I278T). By PCR amplification and sequencing of exon 8 from genomic DNA we have now identified 2 index patients who are homozygous and 5 who are heterozygous for this mutation in a group of 32 patients with CBS deficiency. The mutation was detected in 7 of 10 unrelated families with in vivo B{sub 6} responsiveness, including one with a partial response, and in 0 of 22 B{sub 6} nonresponsive patients. The mutations on the other allele in the compound heterozygotes are still under investigation. We have now observed the I278T mutation in 9 of 20 independent alleles of varied ethnic backgrounds in the subgroup of B{sub 6} responsive patients. These findings, together with the previous report of this mutation in one allele of a B{sub 6} responsive patient, suggest that the I278T mutation is associated with B{sub 6} responsiveness in CBS deficiency. In compound heterozygotes, the degree of B{sub 6} responsiveness may also depend upon the nature of the other mutant allele and/or the interaction between the polypeptide subunits produced by the two mutant allelic genes.

  13. Novel deletion and a new missense mutation (Glu 217 Lys) at the catalytic site in two adenosine deaminase alleles of a patient with neonatal onset adenosine deaminase severe combined immunodeficiency

    Energy Technology Data Exchange (ETDEWEB)

    Hirschhorn, R.; Nicknam, M.N.; Eng, F.; Yang, D.R.; Borkowsky, W. (New York Univ. Medical School of Medicine, NY (United States))

    1992-11-01

    Mutations at the adenosine deaminase (ADA) locus result in a spectrum of disorders, encompassing a fulminant neonatal onset severe combined immunodeficiency (SCID) and childhood onset immunodeficiency, as well as apparently normal immune function. The extent of accumulation of the toxic metabolite, deoxyATP, correlates directly with severity of disease. The authors have now determined the mutations on both alleles of a child with fulminant, neonatal onset ADA SCID and accumulation of extremely high concentrations of deoxyATP. The genotype was consistent with the severely affected phenotype. One allele carried a large deletion that arose by non-homologous recombination and included the first five exons and promoter region. The second allele carried a missense mutation (G[sup 649]A) resulting in replacement of Glu[sup 217], an amino acid involved in the catalytic site, by Lys and predicting a major alteration in charge. Expression of the mutant cDNA on Cos cells confirmed that the mutation abolished enzyme activity. The authors have previously reported that a missense mutation at the preceding codon is similarly associated with neonatal onset ADA SCID and accumulation of extremely high deoxyATP. These findings suggest that genotype-phenotype correlations may be apparent for ADA SCID, despite the role that random variation in exposure to environmental pathogens may play in the initial phenotype. Such genotype-phenotype correlations may be important to consider in evaluating results of ongoing trials of [open quotes]gene[close quotes] and enzyme replacement therapy. 50 refs., 5 figs., 2 tabs.

  14. Copper Binding and Subsequent Aggregation of α-Synuclein Are Modulated by N-Terminal Acetylation and Ablated by the H50Q Missense Mutation.

    Science.gov (United States)

    Mason, Rebecca J; Paskins, Aimee R; Dalton, Caroline F; Smith, David P

    2016-08-30

    The Parkinson's disease-associated protein α-synuclein exhibits significant conformational heterogeneity. Bacterially expressed α-synuclein is known to bind to copper, resulting in the formation of aggregation-prone compact conformations. However, in vivo, α-synuclein undergoes acetylation at its N-terminus. Here the effect of this modification and the pathological H50Q mutation on copper binding and subsequent conformational transitions were investigated by electrospray ionization-ion mobility spectrometry-mass spectrometry. We demonstrate that acetylation perturbs the ability of α-synuclein to bind copper and that the H50Q missense mutation in the presence of N-terminal acetylation prevents copper binding. These modifications and mutations prevent the formation of the most compact conformations and inhibit copper-induced aggregation.

  15. Mouse Model of Human Congenital Heart Disease: Progressive Atrioventricular Block Induced by a Heterozygous Nkx2-5 Homeodomain Missense Mutation.

    Science.gov (United States)

    Chowdhury, Rajib; Ashraf, Hassan; Melanson, Michelle; Tanada, Yohei; Nguyen, Minh; Silberbach, Michael; Wakimoto, Hiroko; Benson, D Woodrow; Anderson, Robert H; Kasahara, Hideko

    2015-10-01

    Heterozygous human NKX2-5 homeodomain (DNA-binding domain) missense mutations are highly penetrant for varied congenital heart defects, including progressive atrioventricular (AV) block requiring pacemaker implantation. We recently replicated this genetic defect in a murine knockin model, in which we demonstrated highly penetrant, pleiotropic cardiac anomalies. In this study, we examined postnatal AV conduction in the knockin mice. A murine knockin model (Arg52Gly, Nkx2-5(+/R52G)) in a 129/Sv background was analyzed by histopathology, surface, and telemetry ECG, and in vivo electrophysiology studies, comparing with control Nkx2-5(+/+) mice at diverse postnatal stages, ranging from postnatal day 1 (P1) to 17 months. PR prolongation (first degree AV block) was present at 4 weeks, 7 months, and 17 months of age, but not at P1 in the mutant mice. Advanced AV block was also occasionally demonstrated in the mutant mice. Electrophysiology studies showed that AV nodal function and right ventricular effective refractory period were impaired in the mutant mice, whereas sinus nodal function was not affected. AV nodal size was significantly smaller in the mutant mice than their controls at 4 weeks of age, corresponding to the presence of PR prolongation, but not P1, suggesting, at least in part, that the conduction abnormalities are the result of a morphologically atrophic AV node. The highly penetrant and progressive AV block phenotype seen in human heterozygous missense mutations in NKX2-5 homeodomain was replicated in mice by knocking in a comparable missense mutation. © 2015 American Heart Association, Inc.

  16. A missense mutation in ALDH18A1, encoding Delta1-pyrroline-5-carboxylate synthase (P5CS), causes an autosomal recessive neurocutaneous syndrome.

    Science.gov (United States)

    Bicknell, Louise S; Pitt, James; Aftimos, Salim; Ramadas, Ram; Maw, Marion A; Robertson, Stephen P

    2008-10-01

    There are several rare syndromes combining wrinkled, redundant skin and neurological abnormalities. Although phenotypic overlap between conditions has suggested that some might be allelic to one another, the aetiology for many of them remains unknown. A consanguineous New Zealand Maori family has been characterised that segregates an autosomal recessive connective tissue disorder (joint dislocations, lax skin) associated with neurological abnormalities (severe global developmental delay, choreoathetosis) without metabolic abnormalities in four affected children. A genome-screen performed under a hypothesis of homozygosity by descent for an ancestral mutation, identified a locus at 10q23 (Z = 3.63). One gene within the candidate interval, ALDH18A1, encoding Delta1-pyrroline-5-carboxylate synthase (P5CS), was considered a plausible disease gene since a missense mutation had previously been shown to cause progressive neurodegeneration, cataracts, skin laxity, joint dislocations and metabolic derangement in a consanguineous Algerian family. A missense mutation, 2350C>T, was identified in ALDH18A1, which predicts the substitution H784Y. H784 is invariant across all phyla and lies within a previously unrecognised, conserved C-terminal motif in P5CS. In an in vivo assay of flux through this metabolic pathway using dermal fibroblasts obtained from an affected individual, proline and ornithine biosynthetic activity of P5CS was not affected by the H784Y substitution. These data suggest that P5CS may possess additional uncharacterised functions that affect connective tissue and central nervous system function.

  17. Identification of a Novel Heterozygous Missense Mutation in the CACNA1F Gene in a Chinese Family with Retinitis Pigmentosa by Next Generation Sequencing

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    Qi Zhou

    2015-01-01

    Full Text Available Background. Retinitis pigmentosa (RP is an inherited retinal degenerative disease, which is clinically and genetically heterogeneous, and the inheritance pattern is complex. In this study, we have intended to study the possible association of certain genes with X-linked RP (XLRP in a Chinese family. Methods. A Chinese family with RP was recruited, and a total of seven individuals were enrolled in this genetic study. Genomic DNA was isolated from peripheral leukocytes, and used for the next generation sequencing (NGS. Results. The affected individual presented the clinical signs of XLRP. A heterozygous missense mutation (c.1555C>T, p.R519W was identified by NGS in exon 13 of the CACNA1F gene on X chromosome, and was confirmed by Sanger sequencing. It showed perfect cosegregation with the disease in the family. The mutation at this position in the CACNA1F gene of RP was found novel by database searching. Conclusion. By using NGS, we have found a novel heterozygous missense mutation (c.1555C>T, p.R519W in CACNA1F gene, which is probably associated with XLRP. The findings might provide new insights into the cause and diagnosis of RP, and have implications for genetic counseling and clinical management in this family.

  18. A novel missense mutation of the ubiquitin protein ligase E3A gene in a patient with Angelman syndrome

    Institute of Scientific and Technical Information of China (English)

    BAI Jin-li; QU Yu-jin; ZOU Li-ping; YANG Xin-ying; LIU Li-jun; SONG Fang

    2011-01-01

    Background Angelman syndrome (AS) is a neurogenetic disorder caused by an expression defect of the maternally inherited copy of ubiquitin protein ligase E3A (UBE3A) gene from chromosome 15. Although the most common genetic defects include maternal deletions of chromosome 15q11-13, paternal uniparental disomy and imprinting defect,mutations in the UBE3A gene have been identified in approximately 10% of AS patients.Methods A Chinese girl of 28 months presented clinical manifestation of AS. Genetic diagnosis and molecular genetic defects were studied by methylation-specific PCR (MS-PCR) and linkage analysis by short tandem repeat (STR). We further performed sequence analysis of all the coding exons and flanking sequences of the UBE3A gene. The novel mutation screening was also performed in 100 unrelated healthy individuals to exclude the possibility of identifying a polymorphism variation.Results The MS-PCR analysis of the patient showed biparental inheritance of chromosome 15 with a normal methylation pattern in the 15q11-q13 region. And STR analysis revealed that the patient also inherited biparental alleles for six microsatellites. A novel mutation, cDNA1199 C>A (p. P400H), in exon 9 of the maternal UBE3A gene, was identified in the patient. Meanwhile, the mutation was observed in the patient's mother who had a normal phenotype.Conclusions It is necessary to perform the UBE3A gene mutation analysis in non-deletion/non-UPD/non-ID patients with AS. The clinical picture of the patient is concordant with that observed in previously reported AS patients with UBE3A mutation.

  19. Novel NR5A1 missense mutation in premature ovarian failure: detection in han chinese indicates causation in different ethnic groups.

    Directory of Open Access Journals (Sweden)

    Xue Jiao

    Full Text Available BACKGROUND: The etiology of most premature ovarian failure (POF cases is usually elusive. Although genetic causes clearly exist and a likely susceptible region of 8q22.3 has been discovered, no predominant explanation exists for POF. More recently, evidences have indicated that mutations in NR5A1 gene could be causative for POF. We therefore screened for mutations in the NR5A1 gene in a large cohort of Chinese women with non-syndromic POF. METHODS: Mutation screening of NR5A1 gene was performed in 400 Han Chinese women with well-defined 46,XX idiopathic non-syndromic POF and 400 controls. Subsequently, functional characterization of the novel mutation identified was evaluated in vitro. RESULTS: A novel heterozygous missense mutation [c.13T>G (p.Tyr5Asp] in NR5A1 was identified in 1 of 384 patients (0.26%. This mutation impaired transcriptional activation on Amh, Inhibin-a, Cyp11a1 and Cyp19a1 gene, as shown by transactivation assays. However, no dominant negative effect was observed, nor was there impact on protein expression and nuclear localization. CONCLUSIONS: This novel mutation p.Tyr5Asp, in a novel non-domain region, is presumed to result in haploinsufficiency. Irrespectively, perturbation in NR5A1 is not a common explanation for POF in Chinese.

  20. Identification of a region required for TSC1 stability by functional analysis of TSC1 missense mutations found in individuals with tuberous sclerosis complex

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    den Dunnen Johan T

    2009-09-01

    Full Text Available Abstract Background Tuberous sclerosis complex (TSC is an autosomal dominant disorder characterised by the development of hamartomas in a variety of organs and tissues. The disease is caused by mutations in either the TSC1 gene on chromosome 9q34, or the TSC2 gene on chromosome 16p13.3. The TSC1 and TSC2 gene products, TSC1 and TSC2, form a protein complex that inhibits signal transduction to the downstream effectors of the mammalian target of rapamycin (mTOR. Recently it has been shown that missense mutations to the TSC1 gene can cause TSC. Methods We have used in vitro biochemical assays to investigate the effects on TSC1 function of TSC1 missense variants submitted to the Leiden Open Variation Database. Results We identified specific substitutions between amino acids 50 and 190 in the N-terminal region of TSC1 that result in reduced steady state levels of the protein and lead to increased mTOR signalling. Conclusion Our results suggest that amino acid residues within the N-terminal region of TSC1 are important for TSC1 function and for maintaining the activity of the TSC1-TSC2 complex.

  1. HEREDITARY FACTOR VII DEFICIENCY IN THE ASIAN ELEPHANT (ELEPHAS MAXIMUS) CAUSED BY A F7 MISSENSE MUTATION.

    Science.gov (United States)

    Lynch, Michael; McGrath, Ken; Raj, Karthik; McLaren, Philippa; Payne, Karen; McCoy, Richard; Giger, Urs

    2017-04-01

    Hereditary disorders and genetic predispositions to disease are rarely reported in captive and free-ranging wildlife, and none have been definitively identified and characterized in elephants. A wild-caught, 41-yr-old male Asian elephant ( Elephas maximus ) without an apparent increased bleeding tendency was consistently found to have prolonged prothrombin times (PTs, mean=55±35 s) compared to 17 other elephants (PT=10±2 s). This elephant's partial thromboplastin times (PTT) fell within the normal range of the other elephants (12-30 s). A prolonged PT in the presence of a normal PTT suggests disruption of the extrinsic pathway via deficiency of coagulation Factor VII (FVII). This elephant's plasma FVII activity was very low (2%) compared to that of 15 other elephants (57-80%), but other coagulation factors' activities did not differ from the control elephants. Sequencing of genomic DNA from ethylenediaminetetraacetic acid blood revealed a single homozygous point mutation (c.202A>G) in the F7 gene of the FVII deficient elephant that was not present in unrelated elephants. This mutation causes an amino acid substitution (p.Arg68Gly) that is predicted to be deleterious. Two living offspring of the affected elephant were heterozygous for the mutation and had normal plasma FVII activities and coagulation profiles. Tissue from a third offspring, a deceased calf, was utilized to show that it was also a heterozygote. A DNA test has been developed to enable the screening of additional elephants for this mutation. Consistent with FVII deficiency investigations in other species, the condition did not cause a serious bleeding tendency in this individual elephant.

  2. Investigating the impact of missense mutations in hCES1 by in silico structure-based approaches

    DEFF Research Database (Denmark)

    Nzabonimpa, Grace Shema; Rasmussen, Henrik Berg; Brunak, Søren

    2016-01-01

    Genetic variations in drug-metabolizing enzymes have been reported to influence pharmacokinetics, drug dosage and other aspects that affect therapeutic outcomes. Most particularly, non-synonymous single-nucleotide polymorphisms (nsSNPs) resulting in amino acid changes disrupt potential functional...... level. Examples of in silico studies of carboxylesterases (CESs) are discussed, ranging from exploring the effect of mutations on enzyme activity to predicting the metabolism of new hCES1 substrates as well as to guiding rational design of CES-selective inhibitors....

  3. Novel missense mutation in the RSPO4 gene in congenital hyponychia and evidence for a polymorphic initiation codon (p.M1I

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    Khan Tahir

    2012-12-01

    Full Text Available Abstract Background Anonychia/hyponychia congenita is a rare autosomal recessive developmental disorder characterized by the absence (anonychia or hypoplasia (hyponuchia of finger- and/or toenails frequently caused by mutations in the R-spondin 4 (RSPO4 gene. Methods Three hypo/anonychia consanguineous Pakistani families were ascertained and genotyped using microsatellite markers spanning the RSPO4 locus on chromosome 20p13. Mutation screening of the RSPO4 gene was carried out by direct sequencing of the entire coding region and all intron-exon boundaries. Results Mutations in the RSPO4 gene were identified in all families including a novel missense mutation c.178C>T (p.R60W and two recurrent variants c.353G>A (p.C118Y and c.3G>A (p.M1I. The c.3G>A variant was identified in unaffected family members and a control sample in a homozygous state. Conclusions This study raises to 17 the number of known RSPO4 mutations and further expands the molecular repertoire causing hypo/anonychia. The c.353G>A emerges as a recurrent change with a possible founder effect in the Pakistani population. Our findings suggest that c.3G>A is not sufficient to cause the disorder and could be considered a polymorphism.

  4. Hypokalemia-induced long QT syndrome with an underlying novel missense mutation in S4-S5 linker of KCNQ1.

    Science.gov (United States)

    Kubota, T; Shimizu, W; Kamakura, S; Horie, M

    2000-09-01

    Congenital long QT syndrome (LQTS) is caused by mutations in at least five genes coding for cardiac potassium or sodium channels that regulate the duration of ventricular action potentials. Acquired LQTS often is associated with drugs or metabolic abnormalities. A 47-year-old woman who presented with marked QT prolongation (QTc = 620 msec(1/2)) and repeated episodes of torsades de pointes associated with hypokalemia (2.6 mEq/L) was screened for mutations in LQTS genes using polymerase chain reaction/single-strand conformation polymorphism (PCR/SSCP). We identified a novel missense mutation in the intracellular linker of S4-S5 domains of KCNQ1, resulting in an amino acid substitution of cysteine for arginine at position 259 (R259C). Whole cell, patch clamp experiments were conducted on COS7 cells transfected with wild-type and/or R259C KCNQ1 with or without KCNE1. Functional analyses of the mutant KCNQ1 subunit on COS7 cells revealed its functional channels in the homozygous state, producing a significantly smaller current than the KCNQ1 channels and a less severe dominant-negative effect on I(Ks). The novel KCNQ1 mutation R259C is the molecular basis for I(Ks) dysfunction underlying an apparently sporadic case of hypokalemia-induced LQTS, consistent with a mild mutation likely to disclose the clinical manifestation of LQTS in a context of severe hypokalemia. Our findings suggest that gene carriers with such mild mutations might not be so rare as commonly expected in patients with acquired LQTS, and stress the importance of mutational analysis for detecting either "silent" forms of congenital LQTS or de novo mutations.

  5. A missense mutation of the gene encoding synaptic vesicle glycoprotein 2A (SV2A confers seizure susceptibility by disrupting amygdalar synaptic GABA release

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    Kentaro Tokudome

    2016-07-01

    Full Text Available Synaptic vesicle glycoprotein 2A (SV2A is specifically expressed in the membranes of synaptic vesicles and modulates action potential-dependent neurotransmitter release. To explore the role of SV2A in the pathogenesis of epileptic disorders, we recently generated a novel rat model (Sv2aL174Q rat carrying a missense mutation of the Sv2a gene and showed that the Sv2aL174Q rats were hypersensitive to kindling development (Tokudome et al., 2016. Here, we further conducted behavioral and neurochemical studies to clarify the pathophysiological mechanisms underlying the seizure vulnerability in Sv2aL174Q rats. Sv2aL174Q rats were highly susceptible to pentylenetetrazole (PTZ-induced seizures, yielding a significantly higher seizure scores and seizure incidence than the control animals. Brain mapping analysis of Fos expression, a biological marker of neural excitation, revealed that the seizure threshold level of PTZ region-specifically elevated Fos expression in the amygdala in Sv2aL174Q rats. In vivo microdialysis study showed that the Sv2aL174Q mutation preferentially reduced high K+ (depolarization-evoked GABA release, but not glutamate release, in the amygdala. In addition, specific control of GABA release by SV2A was supported by its predominant expression in GABAergic neurons, which were co-stained with antibodies against SV2A and glutamate decarboxylase 1. The present results suggest that dysfunction of SV2A by the missense mutation elevates seizure susceptibility in rats by preferentially disrupting synaptic GABA release in the amygdala, illustrating the crucial role of amygdalar SV2A-GABAergic system in epileptogenesis.

  6. A Missense Mutation of the Gene Encoding Synaptic Vesicle Glycoprotein 2A (SV2A) Confers Seizure Susceptibility by Disrupting Amygdalar Synaptic GABA Release

    Science.gov (United States)

    Tokudome, Kentaro; Okumura, Takahiro; Terada, Ryo; Shimizu, Saki; Kunisawa, Naofumi; Mashimo, Tomoji; Serikawa, Tadao; Sasa, Masashi; Ohno, Yukihiro

    2016-01-01

    Synaptic vesicle glycoprotein 2A (SV2A) is specifically expressed in the membranes of synaptic vesicles and modulates action potential-dependent neurotransmitter release. To explore the role of SV2A in the pathogenesis of epileptic disorders, we recently generated a novel rat model (Sv2aL174Q rat) carrying a missense mutation of the Sv2a gene and showed that the Sv2aL174Q rats were hypersensitive to kindling development (Tokudome et al., 2016). Here, we further conducted behavioral and neurochemical studies to clarify the pathophysiological mechanisms underlying the seizure vulnerability in Sv2aL174Q rats. Sv2aL174Q rats were highly susceptible to pentylenetetrazole (PTZ)-induced seizures, yielding a significantly higher seizure scores and seizure incidence than the control animals. Brain mapping analysis of Fos expression, a biological marker of neural excitation, revealed that the seizure threshold level of PTZ region-specifically elevated Fos expression in the amygdala in Sv2aL174Q rats. In vivo microdialysis study showed that the Sv2aL174Q mutation preferentially reduced high K+ (depolarization)-evoked GABA release, but not glutamate release, in the amygdala. In addition, specific control of GABA release by SV2A was supported by its predominant expression in GABAergic neurons, which were co-stained with antibodies against SV2A and glutamate decarboxylase 1. The present results suggest that dysfunction of SV2A by the missense mutation elevates seizure susceptibility in rats by preferentially disrupting synaptic GABA release in the amygdala, illustrating the crucial role of amygdalar SV2A-GABAergic system in epileptogenesis. PMID:27471467

  7. Germline Missense Changes in the APC Gene and Their Relationship to Disease

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    Scott Rodney J

    2004-05-01

    Full Text Available Abstract Familial adenomatous polyposis (FAP is characterized by the presence of hundreds to thousands of adenomas that carpet the entire colon and rectum. Nonsense and frameshift mutations in the adenomatous polyposis coli (APC gene account for the majority of mutations identified to date and predispose primarily to the typical disease phenotype. Some APC mutations are associated with a milder form of the disease known as attenuated FAP. Virtually all mutations that have been described in the APC gene result in the formation of a premature stop codon and very little is known about missense mutations apart from a common Ashkenazi Jewish mutation (1307 K and a British E1317Q missense change. The incidence of missense mutations in the APC gene has been underreported since the APC gene lends itself to analysis using an artificial transcription and translation assay known as the Protein Truncation Test (PTT or the In Vitro Synthetic Protein assay (IVSP. In this report we have used denaturing high performance liquid chromatography to analyse the entire coding sequence of the APC gene to determine if a cohort of patients adhering to the diagnostic criteria of FAP to assess the frequency of missense mutations in the APC gene. Altogether 112 patients were studied and 22 missense mutations were identified. From the total of 22 missense changes, 13 were silent changes and the remaining 9 resulted in amino acid substitutions. One or more of these changes were identified multiple times in 62.5% of the population under study. The results reveal that missense mutations in the APC gene appear not to radically alter protein function but may be associated with more subtle processing of RNA transcripts which in turn could result in the expression of differentially spliced forms of the APC gene which may interfere with the functional activity of the APC protein.

  8. Missense mutations in SH2D1A identified in patients with X-linked lymphoproliferative disease differentially affect the expression and function of SAP.

    Science.gov (United States)

    Hare, Nathan J; Ma, Cindy S; Alvaro, Frank; Nichols, Kim E; Tangye, Stuart G

    2006-07-01

    X-linked lymphoproliferative disease (XLP) is an immunodeficiency resulting from mutations in SH2D1A, which encodes signalling lymphocytic activation molecule (SLAM)-associated protein (SAP). In addition to SLAM, SAP associates with several other cell-surface receptors including 2B4 (CD244), Ly9 (CD229), CD84 and NTB-A. SAP contains a single src-homology-2 domain and acts as an intracellular adaptor protein by recruiting the protein tyrosine kinase FynT to the cytoplasmic domains of some of these receptors, which results in the initiation of specific downstream signal transduction pathways. XLP is likely to result from perturbed signalling through one or more of these SAP-associating receptors. In this study, we identified missense (Y54C, I84T and F87S) and insertion (fs82 --> X103) mutations in four different kindreds affected by XLP. Each mutation dramatically reduced the half-life of SAP, thus diminishing its expression in primary lymphocytes as well as in transfected cell lines. Interestingly, although the Y54C and F87S mutations compromised the ability of SAP to associate with different receptors, the I84T mutation had no effect on the ability of SAP to bind SLAM, CD84 or 2B4. However, signalling downstream of SLAM was reduced in the presence of SAP bearing the I84T mutation. These findings indicate that, irrespective of the type of mutation, signalling through SAP-associating receptors in XLP can be impaired by reducing the expression of SAP, the ability of SAP to bind surface receptors and/or its ability to activate signal transduction downstream of the SLAM-SAP complex.

  9. Detection of three nonsense mutations and one missense mutation in the interleukin-2 receptor [gamma] chain gene in SCIDX1 that differently affect the mRNA processing

    Energy Technology Data Exchange (ETDEWEB)

    Markiewicz, S.; Fischer, A.; Saint Basile, G. de (INSERM, Paris (France)); Subtil, A.; Dautry-Varsat, A. (Institut Pasteur, Paris (France))

    1994-05-01

    The interleukin-2 receptor [gamma] (IL-2R[gamma]) chain gene encodes a 64-kDa protein that not only composes the high-affinity form of the IL-2 binding receptor in association with the 2R [alpha] and [beta] chains, but also participates in at least the IL-4 and IL-7 receptor complexes. Mutations in this gene have recently been shown to cause X-linked severe combined immunodeficiency (SCIDX1). This disease of the immune system results from an early block of T lymphocyte and natural killer (NK) cell differentiation, which leads to a severe cellular and humoral immune defect that is lethal unless treated by bone marrow transplantation. Analysis of the IL-2R[gamma] gene in SCIDX1 patients has revealed the presence of heterogeneous mutations principally located in the extracellular domain of the molecule. We report here three intraexonic mutations and one deletion in the IL-2R[gamma] gene in four SCIDX1 patients. These mutations appear to differentially affect RNA processing, either by decreasing IL-2R[gamma] mRNA level or by the skipping of a constitutive exon. 16 refs., 1 fig.

  10. A-TWinnipeg: Pathogenesis of rare ATM missense mutation c.6200C>A with decreased protein expression and downstream signaling, early-onset dystonia, cancer, and life-threatening radiotoxicity.

    Science.gov (United States)

    Nakamura, Kotoka; Fike, Francesca; Haghayegh, Sara; Saunders-Pullman, Rachel; Dawson, Angelika J; Dörk, Thilo; Gatti, Richard A

    2014-07-01

    We studied 10 Mennonite patients who carry the c.6200C>A missense mutation (p.A2067D) in the ATM gene, all of whom exhibited a phenotypic variant of ataxia-telangiectasia (A-T) that is characterized by early-onset dystonia and late-onset mild ataxia, as previously described. This report provides the pathogenetic evidence for this mutation on cellular functions. Several patients have developed cancer and subsequently experienced life-threatening adverse reactions to radiation (radiotoxicity) and/or chemotherapy. As the c.6200C>A mutation is, thus far, unique to the Mennonite population and is always associated with the same haplotype or haplovariant, it was important to rule out any possible confounding DNA variant on the same haplotype. Lymphoblastoid cells derived from Mennonite patients expressed small amounts of ATM protein, which had no autophosphorylation activity at ATM Ser1981, and trace-to-absent transphosphorylation of downstream ATM targets. A-T lymphoblastoid cells stably transfected with ATM cDNA which had been mutated for c.6200C>A did not show a detectable amount of ATM protein. The same stable cell line with mutated ATM cDNA also showed a trace-to-absent transphosphorylation of downstream ATM targets SMC1pSer966 and KAP1pSer824. From these results, we conclude that c.6200A is the disease-causing ATM mutation on this haplotype. The presence of at least trace amounts of ATM kinase activity on some immunoblots may account for the late-onset, mild ataxia of these patients. The cause of the dystonia remains unclear. Because this dystonia-ataxia phenotype is often encountered in the Mennonite population in association with cancer and adverse reactions to chemotherapy, an early diagnosis is important.

  11. Functional characterization of an AQP0 missense mutation, R33C, that causes dominant congenital lens cataract, reveals impaired cell-to-cell adhesion.

    Science.gov (United States)

    Kumari, Sindhu S; Gandhi, Jason; Mustehsan, Mohammed H; Eren, Semih; Varadaraj, Kulandaiappan

    2013-11-01

    Aquaporin 0 (AQP0) performs dual functions in the lens fiber cells, as a water pore and as a cell-to-cell adhesion molecule. Mutations in AQP0 cause severe lens cataract in both humans and mice. An arginine to cysteine missense mutation at amino acid 33 (R33C) produced congenital autosomal dominant cataract in a Chinese family for five generations. We re-created this mutation in wild type human AQP0 (WT-AQP0) cDNA by site-directed mutagenesis, and cloned and expressed the mutant AQP0 (AQP0-R33C) in heterologous expression systems. Mutant AQP0-R33C showed proper trafficking and membrane localization like WT-AQP0. Functional studies conducted in Xenopus oocytes showed no significant difference (P > 0.05) in water permeability between AQP0-R33C and WT-AQP0. However, the cell-to-cell adhesion property of AQP0-R33C was significantly reduced (P cataract suggest that the conserved positive charge of Extracellular Loop A may play an important role in bringing fiber cells closer. The proposed schematic models illustrate that cell-to-cell adhesion elicited by AQP0 is vital for lens transparency and homeostasis.

  12. SM2PH-db: an interactive system for the integrated analysis of phenotypic consequences of missense mutations in proteins involved in human genetic diseases.

    Science.gov (United States)

    Friedrich, Anne; Garnier, Nicolas; Gagnière, Nicolas; Nguyen, Hoan; Albou, Laurent-Philippe; Biancalana, Valérie; Bettler, Emmanuel; Deléage, Gilbert; Lecompte, Odile; Muller, Jean; Moras, Dino; Mandel, Jean-Louis; Toursel, Thierry; Moulinier, Luc; Poch, Olivier

    2010-02-01

    Understanding how genetic alterations affect gene products at the molecular level represents a first step in the elucidation of the complex relationships between genotypic and phenotypic variations, and is thus a major challenge in the postgenomic era. Here, we present SM2PH-db (http://decrypthon.igbmc.fr/sm2ph), a new database designed to investigate structural and functional impacts of missense mutations and their phenotypic effects in the context of human genetic diseases. A wealth of up-to-date interconnected information is provided for each of the 2,249 disease-related entry proteins (August 2009), including data retrieved from biological databases and data generated from a Sequence-Structure-Evolution Inference in Systems-based approach, such as multiple alignments, three-dimensional structural models, and multidimensional (physicochemical, functional, structural, and evolutionary) characterizations of mutations. SM2PH-db provides a robust infrastructure associated with interactive analysis tools supporting in-depth study and interpretation of the molecular consequences of mutations, with the more long-term goal of elucidating the chain of events leading from a molecular defect to its pathology. The entire content of SM2PH-db is regularly and automatically updated thanks to a computational grid data federation facilities provided in the context of the Decrypthon program.

  13. The albinism of the feral Asinara white donkeys (Equus asinus) is determined by a missense mutation in a highly conserved position of the tyrosinase (TYR) gene deduced protein.

    Science.gov (United States)

    Utzeri, V J; Bertolini, F; Ribani, A; Schiavo, G; Dall'Olio, S; Fontanesi, L

    2016-02-01

    A feral donkey population (Equus asinus), living in the Asinara National Park (an island north-west of Sardinia, Italy), includes a unique white albino donkey subpopulation or colour morph that is a major attraction of this park. Disrupting mutations in the tyrosinase (TYR) gene are known to cause recessive albinisms in humans (oculocutaneous albinism Type 1; OCA1) and other species. In this study, we analysed the donkey TYR gene as a strong candidate to identify the causative mutation of the albinism of these donkeys. The TYR gene was sequenced from 13 donkeys (seven Asinara white albino and six coloured animals). Seven single nucleotide polymorphisms were identified. A missense mutation (c.604C>G; p.His202Asp) in a highly conserved amino acid position (even across kingdoms), which disrupts the first copper-binding site (CuA) of functional protein, was identified in the homozygous condition (G/G or D/D) in all Asinara white albino donkeys and in the albino son of a trio (the grey parents had genotype C/G or H/D), supporting the recessive mode of inheritance of this mutation. Genotyping 82 donkeys confirmed that Asinara albino donkeys had genotype G/G whereas all other coloured donkeys had genotype C/C or C/G. Across-population association between the c.604C>G genotypes and the albino coat colour was highly significant (P = 6.17E-18). The identification of the causative mutation of the albinism in the Asinara white donkeys might open new perspectives to study the dynamics of this putative deleterious allele in a feral population and to manage this interesting animal genetic resource.

  14. A missense mutation in CRYBB2 leads to progressive congenital membranous cataract by impacting the solubility and function of βB2-crystallin.

    Science.gov (United States)

    Chen, Weirong; Chen, Xiaoyun; Hu, Zhengmao; Lin, Haotian; Zhou, Fengqi; Luo, Lixia; Zhang, Xinyu; Zhong, Xiaojian; Yang, Ye; Wu, Changrui; Lin, Zhuoling; Ye, Shaobi; Liu, Yizhi

    2013-01-01

    Congenital cataract is a major cause of visual impairment and childhood blindness. The solubility and stability of crystallin proteins play critical roles in maintaining the optical transparency of the lens during the life span. Previous studies have shown that approximately 8.3%~25% of congenital cataracts are inherited, and mutations in crystallins are the most common. In this study, we attempted to identify the genetic defect in a four-generation family affected with congenital cataracts. The congenital cataract phenotype of this four-generation family was identified as membranous cataract by slit-lamp photography. Mutation screening of the candidate genes detected a heterozygous c.465G → C change in the exon6 of the βB2-crystallin gene (CRYBB2) in all family members affected with cataracts, resulting in the substitution of a highly conserved Tryptophan to Cystine (p.W151C). The mutation was confirmed by restriction fragment length polymorphism (RFLP) analysis and found that the transition resulted in the absence of a BslI restriction site in the affected members of the pedigree. The outcome of PolyPhen-2 and SIFT analysis predicted that this W151C mutation would probably damage to the structure and function of βB2-crystallin. Wild type (wt) and W151C mutant βB2-crystallin were expressed in human lens epithelial cells (HLECs), and the fluorescence results showed that Wt-βB2-crystallin was evenly distributed throughout the cells, whereas approximately 34.7% of cells transfected with the W151C mutant βB2-crystallin formed intracellular aggregates. Taken together, these data suggest that the missense mutation in CRYBB2 gene leads to progressive congenital membranous cataract by impacting the solubility and function of βB2-crystallin.

  15. A missense mutation in CRYBB2 leads to progressive congenital membranous cataract by impacting the solubility and function of βB2-crystallin.

    Directory of Open Access Journals (Sweden)

    Weirong Chen

    Full Text Available Congenital cataract is a major cause of visual impairment and childhood blindness. The solubility and stability of crystallin proteins play critical roles in maintaining the optical transparency of the lens during the life span. Previous studies have shown that approximately 8.3%~25% of congenital cataracts are inherited, and mutations in crystallins are the most common. In this study, we attempted to identify the genetic defect in a four-generation family affected with congenital cataracts. The congenital cataract phenotype of this four-generation family was identified as membranous cataract by slit-lamp photography. Mutation screening of the candidate genes detected a heterozygous c.465G → C change in the exon6 of the βB2-crystallin gene (CRYBB2 in all family members affected with cataracts, resulting in the substitution of a highly conserved Tryptophan to Cystine (p.W151C. The mutation was confirmed by restriction fragment length polymorphism (RFLP analysis and found that the transition resulted in the absence of a BslI restriction site in the affected members of the pedigree. The outcome of PolyPhen-2 and SIFT analysis predicted that this W151C mutation would probably damage to the structure and function of βB2-crystallin. Wild type (wt and W151C mutant βB2-crystallin were expressed in human lens epithelial cells (HLECs, and the fluorescence results showed that Wt-βB2-crystallin was evenly distributed throughout the cells, whereas approximately 34.7% of cells transfected with the W151C mutant βB2-crystallin formed intracellular aggregates. Taken together, these data suggest that the missense mutation in CRYBB2 gene leads to progressive congenital membranous cataract by impacting the solubility and function of βB2-crystallin.

  16. A novel missense mutation in the C-terminal domain of lipoprotein lipase (Glu410-->Val) leads to enzyme inactivation and familial chylomicronemia.

    Science.gov (United States)

    Previato, L; Guardamagna, O; Dugi, K A; Ronan, R; Talley, G D; Santamarina-Fojo, S; Brewer, H B

    1994-09-01

    Lipoprotein lipase (LPL) is a complex enzyme consisting of multiple functional domains essential for the initial hydrolysis of triglycerides present in plasma lipoproteins. Previous studies have localized the catalytic domain of LPL, responsible for the hydrolytic function of the enzyme, to the N-terminus whereas the C-terminal end may play a role in lipid and heparin binding. To date, most described missense mutations resulting in a nonfunctional LPL have been located in the N-terminal region of the enzyme. In this manuscript we describe the defect in the LPL gene of a patient with triglycerides ranging from normal to 12,000 mg/dl, low LPL mass, and no LPL activity in post-heparin plasma. Sequencing of patient PCR-amplified DNA identified two separate mutations in the C-terminal domain of LPL: an A-->T transversion at nucleotide 1484 resulting in a Glu410-->Val substitution and a C-->G mutation at position 1595 that introduces a premature stop codon at position 447. Digestion with MaeIII and MnII established that the patient is a true homozygote for both mutations. In order to investigate the functional significance of these defects, mutant enzymes containing either the Val410 or the Ter447 mutations as well as both Val410 and Ter447, were expressed in vitro. Compared to the wild-type enzyme, LPL447 demonstrated a moderate reduction of specific activity using triolein (70% of normal) and tributyrin (74% of normal) substrates, while LPL410 had a significant (11% and 23% of normal) reduction of the normal lipase and esterase specific activities, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. A comprehensive computational study on pathogenic mis-sense mutations spanning the RING2 and REP domains of Parkin protein.

    Science.gov (United States)

    Biswas, Ria; Bagchi, Angshuman

    2017-04-30

    Various mutations in PARK2 gene, which encodes the protein parkin, are significantly associated with the onset of autosomal recessive juvenile Parkinson (ARJP) in neuronal cells. Parkin is a multi domain protein, the N-terminal part contains the Ubl and the C-terminal part consists of four zinc coordinating domains, viz., RING0, RING1, in between ring (IBR) and RING2. Disease mutations are spread over all the domains of Parkin, although mutations in some regions may affect the functionality of Parkin more adversely. The mutations in the RING2 domain are seen to abolish the neuroprotective E3 ligase activity of Parkin. In this current work, we carried out detailed in silico analysis to study the extent of pathogenicity of mutations spanning the Parkin RING2 domain and the adjoining REP region by SIFT, Mutation Accessor, PolyPhen2, SNPs and GO, GV/GD and I-mutant. To study the structural and functional implications of these mutations on RING2-REP domain of Parkin, we studied the solvent accessibility (SASA/RSA), hydrophobicity, intra-molecular hydrogen bonding profile and domain analysis by various computational tools. Finally, we analysed the interaction energy profiles of the mutants and compared them to the wild type protein using Discovery studio 2.5. By comparing the various analyses it could be safely concluded that except P437L and A379V mutations, all other mutations were potentially deleterious affecting various structural aspects of RING2 domain architecture. This study is based purely on computational approach which has the potential to identify disease mutations and the information could further be used in treatment of diseases and prognosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Novel Homozygous Missense Mutation in SPG20 Gene Results in Troyer Syndrome Associated with Mitochondrial Cytochrome c Oxidase Deficiency.

    Science.gov (United States)

    Spiegel, Ronen; Soiferman, Devorah; Shaag, Avraham; Shalev, Stavit; Elpeleg, Orly; Saada, Ann

    2016-08-19

    Troyer syndrome is an autosomal recessive form of hereditary spastic paraplegia (HSP) caused by deleterious mutations in the SPG20 gene. Although the disease is associated with a loss of function mechanism of spartin, the protein encoded by SPG20, the precise pathogenesis is yet to be elucidated. Recent data indicated an important role for spartin in both mitochondrial maintenance and function. Here we report a child presenting with progressive spastic paraparesis, generalized muscle weakness, dysarthria, impaired growth, and severe isolated decrease in muscle cytochrome c oxidase (COX) activity. Whole exome sequencing identified the homozygous c.988A>G variant in SPG20 gene (p.Met330Val) resulting in almost complete loss of spartin in skeletal muscle. Further analyses demonstrated significant tissue specific reduction of COX 4, a nuclear encoded subunit of COX, in muscle suggesting a role for spartin in proper mitochondrial respiratory chain function mediated by COX activity. Our findings need to be verified in other Troyer syndrome patients in order to classify it as a form of HSP caused by mitochondrial dysfunction.

  19. Convergent Evolution of Head Crests in Two Domesticated Columbids Is Associated with Different Missense Mutations in EphB2.

    Science.gov (United States)

    Vickrey, Anna I; Domyan, Eric T; Horvath, Martin P; Shapiro, Michael D

    2015-10-01

    Head crests are important display structures in wild bird species and are also common in domesticated lineages. Many breeds of domestic rock pigeon (Columba livia) have crests of reversed occipital feathers, and this recessive trait is associated with a nonsynonymous coding mutation in the intracellular kinase domain of EphB2 (Ephrin receptor B2). The domestic ringneck dove (Streptopelia risoria) also has a recessive crested morph with reversed occipital feathers, and interspecific crosses between crested doves and pigeons produce crested offspring, suggesting a similar genetic basis for this trait in both species. We therefore investigated EphB2 as a candidate for the head crest phenotype of ringneck doves and identified a nonsynonymous coding mutation in the intracellular kinase domain that is significantly associated with the crested morph. This mutation is over 100 amino acid positions away from the crest mutation found in rock pigeons, yet both mutations are predicted to negatively affect the function of ATP-binding pocket. Furthermore, bacterial toxicity assays suggest that "crest" mutations in both species severely impact kinase activity. We conclude that head crests are associated with different mutations in the same functional domain of the same gene in two different columbid species, thereby representing striking evolutionary convergence in morphology and molecules. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. GM2 gangliosidosis associated with a HEXA missense mutation in Japanese Chin dogs: a potential model for Tay Sachs disease.

    Science.gov (United States)

    Sanders, Douglas N; Zeng, Rong; Wenger, David A; Johnson, Gary S; Johnson, Gayle C; Decker, Jared E; Katz, Martin L; Platt, Simon R; O'Brien, Dennis P

    2013-01-01

    GM2 gangliosidosis is a fatal lysosomal storage disease caused by a deficiency of β-hexosaminidase (EC 3.2.1.52). There are two major isoforms of the enzyme: hexosaminidase A composed of an α and a β subunit (encoded by HEXA and HEXB genes, respectively); and, hexosaminidase B composed of two β subunits. Hexosaminidase A requires an activator protein encoded by GM2A to catabolize GM2 ganglioside, but even in the absence of the activator protein, it can hydrolyze the synthetic substrates commonly used to assess enzyme activity. GM2 gangliosidosis has been reported in Japanese Chin dogs, and we identified the disease in two related Japanese Chin dogs based on clinical signs, histopathology and elevated brain GM2 gangliosides. As in previous reports, we found normal or elevated hexosaminidase activity when measured with the synthetic substrates. This suggested that the canine disease is analogous to human AB variant of G(M2) gangliosidosis, which results from mutations in GM2A. However, only common neutral single nucleotide polymorphisms were found upon sequence analysis of the canine ortholog of GM2A from the affected Japanese Chins. When the same DNA samples were used to sequence HEXA, we identified a homozygous HEXA:c967G>A transition which predicts a p.E323K substitution. The glutamyl moiety at 323 is known to make an essential contribution to the active site of hexosaminidase A, and none of the 128 normal Japanese Chins and 92 normal dogs of other breeds that we tested was homozygous for HEXA:c967A. Thus it appears that the HEXA:c967G>A transition is responsible for the GM2 gangliosidosis in Japanese Chins.

  1. Missense and nonsense mutations in melanocortin 1 receptor (MC1R gene of different goat breeds: association with red and black coat colour phenotypes but with unexpected evidences

    Directory of Open Access Journals (Sweden)

    Davoli Roberta

    2009-08-01

    Full Text Available Abstract Background Agouti and Extension loci control the relative amount of eumelanin and pheomelanin production in melanocytes that, in turn, affects pigmentation of skin and hair. The Extension locus encodes the melanocortin 1 receptor (MC1R whose permanent activation, caused by functional mutations, results in black coat colour, whereas other inactivating mutations cause red coat colour in different mammals. Results The whole coding region of the MC1R gene was sequenced in goats of six different breeds showing different coat colours (Girgentana, white cream with usually small red spots in the face; Maltese, white with black cheeks and ears; Derivata di Siria, solid red; Murciano-Granadina, solid black or solid brown; Camosciata delle Alpi, brown with black stripes; Saanen, white; F1 goats and the parental animals. Five single nucleotide polymorphisms (SNPs were identified: one nonsense mutation (p.Q225X, three missense mutations (p.A81V, p.F250V, and p.C267W, and one silent mutation. The stop codon at position 225 should cause the production of a shorter MC1R protein whose functionality may be altered. These SNPs were investigated in a larger sample of animals belonging to the six breeds. The Girgentana breed was almost fixed for the p.225X allele. However, there was not complete association between the presence of red spots in the face and the presence of this allele in homozygous condition. The same allele was identified in the Derivata di Siria breed. However, its frequency was only 33%, despite the fact that these animals are completely red. The p.267W allele was present in all Murciano-Granadina black goats, whereas it was never identified in the brown ones. Moreover, the same substitution was present in almost all Maltese goats providing evidence of association between this mutation and black coat colour. Conclusion According to the results obtained in the investigated goat breeds, MC1R mutations may determine eumelanic and pheomelanic

  2. Spectrum of MECP2 gene mutations in a cohort of Indian patients with Rett syndrome: report of two novel mutations.

    Science.gov (United States)

    Das, Dhanjit Kumar; Raha, Sarbani; Sanghavi, Daksha; Maitra, Anurupa; Udani, Vrajesh

    2013-02-15

    Rett syndrome (RTT) is an X-linked neurodevelopmental disorder, primarily affecting females and characterized by developmental regression, epilepsy, stereotypical hand movements, and motor abnormalities. Its prevalence is about 1 in 10,000 female births. Rett syndrome is caused by mutations within methyl CpG-binding protein 2 (MECP2) gene. Over 270 individual nucleotide changes which cause pathogenic mutations have been reported. However, eight most commonly occurring missense and nonsense mutations account for almost 70% of all patients. We screened 90 individuals with Rett syndrome phenotype. A total of 19 different MECP2 mutations and polymorphisms were identified in 27 patients. Of the 19 mutations, we identified 7 (37%) frameshift, 6 (31%) nonsense, 14 (74%) missense mutations and one duplication (5%). The most frequent pathogenic changes were: missense p.T158M (11%), p.R133C (7.4%), and p.R306C (7.4%) and nonsense p.R168X (11%), p.R255X (7.4%) mutations. We have identified two novel mutations namely p.385-388delPLPP present in atypical patients and p.Glu290AlafsX38 present in a classical patient of Rett syndrome. Sequence homology for p.385-388delPLPP mutation revealed that these 4 amino acids were conserved across mammalian species. This indicated the importance of these 4 amino acids in structure and function of the protein. A novel variant p.T479T has also been identified in a patient with atypical Rett syndrome. A total of 62 (69%) patients remained without molecular genetics diagnosis that necessitates further search for mutations in other genes like CDKL5 and FOXG1 that are known to cause Rett phenotype. The majority of mutations are detected in exon 4 and only one mutation was present in exon 3. Therefore, our study suggests the need for screening exon 4 of MECP2 as first line of diagnosis in these patients.

  3. A Novel Abetalipoproteinemia Missense Mutation Highlights the Importance of N-Terminal β-Barrel in Microsomal Triglyceride Transfer Protein Function

    Science.gov (United States)

    Walsh, Meghan T.; Iqbal, Jahangir; Josekutty, Joby; Soh, James; Di Leo, Enza; Özaydin, Eda; Gündüz, Mehmet; Tarugi, Patrizia; Hussain, M. Mahmood

    2015-01-01

    Background The use of microsomal triglyceride transfer protein (MTP) inhibitors is limited to severe hyperlipidemias due to associated hepatosteatosis and gastrointestinal adverse effects. Comprehensive knowledge about the structure-function of MTP might help design new molecules that avoid steatosis. Characterization of mutations in MTP causing abetalipoproteinemia have revealed that the central α-helical and C-terminal β-sheet domains are important for protein disulfide isomerase (PDI) binding and lipid transfer activity. Our aim was to identify and characterize mutations in the N-terminal domain to understand its function. Methods and Results We identified a novel missense mutation (D169V) in a 4-month old Turkish male with severe signs of ABL. To study the effect of this mutation on MTP function, we created mutants via site-directed mutagenesis. Although D169V was expressed in the endoplasmic reticulum and interacted with apoB17, it was unable to bind PDI, transfer lipids, and support apoB secretion. Computational modeling suggested that D169 could form an internal salt bridge with K187 and K189. Mutagenesis of these lysines to leucines abolished PDI heterodimerization, lipid transfer, and apoB secretion, without affecting apoB17 binding. Further, mutants with preserved charges (D169E, K187R, K189R) rescued these activities. Conclusions D169V is detrimental because it disrupts an internal salt bridge leading to loss of PDI binding and lipid transfer activities; however, it does not affect apoB-binding. Thus, the N-terminal domain of MTP is also important for its lipid transfer activity. PMID:26224785

  4. Reduced susceptibility to polyenes associated with a missense mutation in the ERG6 gene in a clinical isolate of Candida glabrata with pseudohyphal growth.

    Science.gov (United States)

    Vandeputte, Patrick; Tronchin, Guy; Bergès, Thierry; Hennequin, Christophe; Chabasse, Dominique; Bouchara, Jean-Philippe

    2007-03-01

    Little information is available about the molecular mechanisms responsible for polyene resistance in pathogenic yeasts. A clinical isolate of Candida glabrata with a poor susceptibility to polyenes, as determined by disk diffusion method and confirmed by determination of MIC, was recovered from a patient treated with amphotericin B. Quantitative analysis of sterols revealed a lack of ergosterol and an accumulation of late sterol intermediates, suggesting a defect in the final steps of the ergosterol pathway. Sequencing of CgERG11, CgERG6, CgERG5, and CgERG4 genes revealed exclusively a unique missense mutation in CgERG6 leading to the substitution of a cysteine by a phenylalanine in the corresponding protein. In addition, real-time reverse transcription-PCR demonstrated an overexpression of genes encoding enzymes involved in late steps of the ergosterol pathway. Moreover, this isolate exhibited a pseudohyphal growth whatever the culture medium used, and ultrastructural changes of the cell wall of blastoconidia were seen consisting in a thinner inner layer. Cell wall alterations were also suggested by the higher susceptibility of growing cells to Calcofluor white. Additionally, complementation of this isolate with a wild-type copy of the CgERG6 gene restored susceptibility to polyenes and a classical morphology. Together, these results demonstrated that mutation in the CgERG6 gene may lead to a reduced susceptibility to polyenes and to a pseudohyphal growth due to the subsequent changes in sterol content of the plasma membrane.

  5. Two missense mutations of H type alpha(1,2)fucosyltransferase gene (FUT1) responsible for para-Bombay phenotype.

    Science.gov (United States)

    Wang, B; Koda, Y; Soejima, M; Kimura, H

    1997-01-01

    Rare individuals (Bombay and para-Bombay phenotypes) fail to express the A, B and H antigens on erythrocyte membranes because of a lack in the H gene (FUT1)-encoded alpha(1,2)fucosyltransferase activity. In this study, we have found a para-Bombay individual (Bmh) who expressed B and H antigens in saliva but not on red blood cells. The FUT1 alleles of this person contained two single base changes (T460C and G1042A) in the coding region relative to the wild type allele. These substitutions may result in changes in two amino acid residues (Y154H and E348K). Since the T460C and G1042A mutations destroy endonuclease RsaI and AvaI sites, respectively, we tested for these mutations using PCR-RFLP. Our findings indicated that this para-Bombay person was homozygous for the T460C and G1042A mutations, and that neither of these mutations was found in 136 randomly selected Japanese individuals. The measurement of the alpha(1,2)fucosyltransferase activity after transient expression of the FUT1 alleles in COS-7 cells indicated that the H-deficient allele-encoded enzyme had no detectable activity. Moreover, transfection by chimera FUT1 allele contains only the T460C mutation, or only the G1042A mutation, and yielded 1.0 or 9.3%, respectively, of the activities compared to transfection by the wild type allele. These results suggest that the two mutations in combination are responsible for the inactivation of the FUT1-encoded enzyme activity.

  6. Three novel ANO5 missense mutations in Caucasian and Chinese families and sporadic cases with gnathodiaphyseal dysplasia

    Science.gov (United States)

    Jin, Lingling; Liu, Yi; Sun, Fanyue; Collins, Michael T.; Blackwell, Keith; Woo, Albert S.; Reichenberger, Ernst J.; Hu, Ying

    2017-01-01

    Gnathodiaphyseal dysplasia (GDD; MIM#166260) is an autosomal dominant syndrome with characteristic cemento-osseous lesions of jawbones, bone fragility, and diaphyseal sclerosis of tubular bones. To date, only five mutations in the proposed calcium-activated chloride channel ANO5/TMEM16E gene have been identified. In this study, we describe two families and two singular patients with three new mutations. One Caucasian family with seven affected members exhibited frequent bone fractures and florid osseous dysplasia (p.Cys356Tyr), while one Chinese family with two affected members suffered from cementoma and purulent osteomyelitis (p.Cys360Tyr). In addition, two different novel mutations (p.Gly518Glu and p.Arg215Gly) were identified in sporadic patients without family history. In vitro studies overexpressing GDD mutations (p.Cys356Tyr and p.Cys360Tyr) showed significantly reduced ANO5 protein. It appears that all GDD mutations known so far locate in an extracellular domain following the first transmembrane domain or in the 4th putative transmembrane domain. Both wild-type and mutant ANO5 protein localize to the endoplasmic reticulum. After Ano5 gene knock-down with shRNA in MC3T3-E1 osteoblast precursors we saw elevated expression of osteoblast-related genes such as Col1a1, osteocalcin, osterix and Runx2 as well as increased mineral nodule formation in differentiating cells. Our data suggest that ANO5 plays a role in osteoblast differentiation. PMID:28176803

  7. Novel PAX9 and COL1A2 missense mutations causing tooth agenesis and OI/DGI without skeletal abnormalities.

    Directory of Open Access Journals (Sweden)

    Shih-Kai Wang

    Full Text Available Inherited dentin defects are classified into three types of dentinogenesis imperfecta (DGI and two types of dentin dysplasia (DD. The genetic etiology of DD-I is unknown. Defects in dentin sialophosphoprotein (DSPP cause DD type II and DGI types II and III. DGI type I is the oral manifestation of osteogenesis imperfecta (OI, a systemic disease typically caused by defects in COL1A1 or COL1A2. Mutations in MSX1, PAX9, AXIN2, EDA and WNT10A can cause non-syndromic familial tooth agenesis. In this study a simplex pattern of clinical dentinogenesis imperfecta juxtaposed with a dominant pattern of hypodontia (mild tooth agenesis was evaluated, and available family members were recruited. Mutational analyses of the candidate genes for DGI and hypodontia were performed and the results validated. A spontaneous novel mutation in COL1A2 (c.1171G>A; p.Gly391Ser causing only dentin defects and a novel mutation in PAX9 (c.43T>A; p.Phe15Ile causing hypodontia were identified and correlated with the phenotypic presentations in the family. Bone radiographs of the proband's dominant leg and foot were within normal limits. We conclude that when no DSPP mutation is identified in clinically determined isolated DGI cases, COL1A1 and COL1A2 should be considered as candidate genes. PAX9 mutation p.Phe15Ile within the N-terminal β-hairpin structure of the PAX9 paired domain causes tooth agenesis.

  8. Combination of Whole Genome Sequencing, Linkage and Functional Studies Implicates a Missense Mutation in Titin as a Cause of Autosomal Dominant Cardiomyopathy with Features of Left Ventricular Non-Compaction

    Science.gov (United States)

    Hooper, Charlotte; Ormondroyd, Liz; Pagnamenta, Alistair; Lise, Stefano; Salatino, Silvia; Knight, Samantha JL; Taylor, Jenny C.; Thomson, Kate L.; Arnold, Linda; Chatziefthimiou, Spyros D.; Konarev, Petr V.; Wilmanns, Matthias; Ehler, Elisabeth; Ghisleni, Andrea; Gautel, Mathias; Blair, Edward; Watkins, Hugh; Gehmlich, Katja

    2016-01-01

    Background High throughput next generation sequencing techniques have made whole genome sequencing accessible in clinical practice, however, the abundance of variation in the human genomes makes the identification of a disease-causing mutation on a background of benign rare variants challenging. Methods and Results Here we combine whole genome sequencing with linkage analysis in a three-generation family affected by cardiomyopathy with features of autosomal dominant left-ventricular non-compaction cardiomyopathy. A missense mutation in the giant protein titin is the only plausible disease-causing variant that segregates with disease amongst the eight surviving affected individuals, with interrogation of the entire genome excluding other potential causes. This A178D missense mutation, affecting a conserved residue in the second immunoglobulin-like domain of titin, was introduced in a bacterially expressed recombinant protein fragment and biophysically characterised in comparison to its wild-type counterpart. Multiple experiments, including size exclusion chromatography, small angle X-ray scattering and circular dichroism spectroscopy suggest partial unfolding and domain destabilisation in the presence of the mutation. Moreover, binding experiments in mammalian cells show that the mutation markedly impairs binding to the titin ligand telethonin. Conclusions Here we present genetic and functional evidence implicating the novel A178D missense mutation in titin as the cause of a highly penetrant familial cardiomyopathy with features of left-ventricular non-compaction. This expands the spectrum of titin’s roles in cardiomyopathies. It furthermore highlights that rare titin missense variants, currently often ignored or left un-interpreted, should be considered to be relevant for cardiomyopathies and can be identified by the approach presented here. PMID:27625337

  9. A novel missense mutation in the SLC6A19 gene in a Chinese family with Hartnup disorder.

    Science.gov (United States)

    Zheng, Yanhong; Zhou, Cuncai; Huang, Yongchu; Bu, Dingfang; Zhu, Xuejun; Jiang, Wei

    2009-04-01

    Hartnup disease is a rare autosomal-recessive abnormality of renal and gastrointestinal neutral amino acid transport associated with neurologic, psychiatric, and dermatologic symptoms. Mutations in the SLC6A19 gene have been proposed to be responsible for the underlying changes in this disorder. To investigate a pedigree with Hartnup disorder and to search for the mutation in the SLC6A19 gene in this pedigree. The encoding exons of the SLC6A19 gene were amplified and sequenced from genomic DNA samples. Amino acids were determined in urine samples from the proband and her family members. The proband and her brother had a homozygous mutation of c.850G > A in the SLC6A19 gene, causing G284R in the transmembrane domain of the SLC6A19 transporter, inherited from their parents who were heterozygous carriers. Their urine samples showed increased values of eight neutral amino acids. We found a novel homozygous mutation of G284R in the transmembrane domain of the SLC6A19 transporter in the proband, with typical dermatologic and neurologic manifestations and increased levels of urinary neutral amino acids.

  10. Congenital bovine spinal dysmyelination is caused by a missense mutation in the SPAST gene

    DEFF Research Database (Denmark)

    Thomsen, Bo; Nissen, Peter H.; Agerholm, Jørgen S

    2010-01-01

    European cattle breeds upgraded with ABS. Here, we show that the disease locus on bovine chromosome 11 harbors the SPAST gene that, when mutated, is responsible for the human disorder hereditary spastic paraplegia (HSP). Initially, SPAST encoding Spastin was considered a less likely candidate gene for BSD...

  11. Heterozygosity for a Novel Missense Mutation in the ITGB4 Gene Associated With Autosomal Dominant Epidermolysis Bullosa

    NARCIS (Netherlands)

    Turcan, Iana; Pasmooij, Anna M G; van den Akker, Peter C; Lemmink, Henny; Halmos, Gyorgy B; Sinke, Richard J; Jonkman, Marcel F

    2016-01-01

    Importance: Epidermolysis bullosa (EB) is a group of mechanobullous genodermatoses characterized by the fragility of skin and mucous membranes. Mutations in the ITGA6 and ITGB4 genes, encoding the hemidesmosomal protein α6β4-integrin, have been involved in the pathogenesis of EB. To date, the inheri

  12. Hereditary angioedema in a Jordanian family with a novel missense mutation in the C1-inhibitor N-terminal domain.

    Science.gov (United States)

    Jaradat, Saied A; Caccia, Sonia; Rawashdeh, Rifaat; Melhem, Motasem; Al-Hawamdeh, Ali; Carzaniga, Thomas; Haddad, Hazem

    2016-03-01

    Hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) is an autosomal dominant disease caused by mutations in the SERPING1 gene. A Jordanian family, including 14 individuals with C1-INH-HAE clinical symptoms, was studied. In the propositus and his parents, SERPING1 had four mutations leading to amino acid substitutions. Two are known polymorphic variants (c.167T>C; p.Val34Ala and c.1438G>A; p.Val458Met), the others are newly described. One (c.203C>T; p.Thr46Ile) is located in the N-terminal domain of the C1-inhibitor protein and segregates with angioedema symptoms in the family. The other (c.800C>T; p.Ala245Val) belongs to the serpin domain, and derives from the unaffected father. DNA from additional 24 family members were screened for c.203C>T mutation in the target gene. All individuals heterozygous for the c.203C>T mutation had antigenic and functional plasma levels of C1-inhibitor below 50% of normal, confirming the diagnosis of type I C1-INH-HAE. Angioedema symptoms were present in 14 of 16 subjects carrier for the c.203T allele. Among these subjects, those carrying the c.800T variation had more severe and frequent symptoms than subjects without this mutation. This family-based study provides the first evidence that multiple amino acid substitutions in SERPING1 could influence C1-INH-HAE phenotype.

  13. Rats with a missense mutation in Atm display neuroinflammation and neurodegeneration subsequent to accumulation of cytosolic DNA following unrepaired DNA damage.

    Science.gov (United States)

    Quek, Hazel; Luff, John; Cheung, KaGeen; Kozlov, Sergei; Gatei, Magtouf; Lee, C Soon; Bellingham, Mark C; Noakes, Peter G; Lim, Yi Chieh; Barnett, Nigel L; Dingwall, Steven; Wolvetang, Ernst; Mashimo, Tomoji; Roberts, Tara L; Lavin, Martin F

    2016-11-28

    Mutations in the ataxia-telangiectasia (A-T)-mutated (ATM) gene give rise to the human genetic disorder A-T, characterized by immunodeficiency, cancer predisposition, and neurodegeneration. Whereas a series of animal models recapitulate much of the A-T phenotype, they fail to present with ataxia or neurodegeneration. We describe here the generation of an Atm missense mutant [amino acid change of leucine (L) to proline (P) at position 2262 (L2262P)] rat by intracytoplasmic injection (ICSI) of mutant sperm into oocytes. Atm-mutant rats (Atm(L2262P/L2262P)) expressed low levels of ATM protein, suggesting a destabilizing effect of the mutation, and had a significantly reduced lifespan compared with Atm(+/+) Whereas these rats did not show cerebellar atrophy, they succumbed to hind-limb paralysis (45%), and the remainder developed tumors. Closer examination revealed the presence of both dsDNA and ssDNA in the cytoplasm of cells in the hippocampus, cerebellum, and spinal cord of Atm(L2262P/L2262P) rats. Significantly increased levels of IFN-β and IL-1β in all 3 tissues were indicative of DNA damage induction of the type 1 IFN response. This was further supported by NF-κB activation, as evidenced by p65 phosphorylation (P65) and translocation to the nucleus in the spinal cord and parahippocampus. Other evidence of neuroinflammation in the brain and spinal cord was the loss of motor neurons and the presence of increased activation of microglia. These data provide support for a proinflammatory phenotype that is manifested in the Atm mutant rat as hind-limb paralysis. This mutant represents a useful model to investigate the importance of neuroinflammation in A-T .

  14. Functional Analysis of a Missense Mutation in the Serine Protease Inhibitor SPINT2 Associated with Congenital Sodium Diarrhea

    Science.gov (United States)

    Faller, Nicolas; Gautschi, Ivan; Schild, Laurent

    2014-01-01

    Membrane-bound serine proteases play important roles in different biological processes. Their regulation by endogenous inhibitors is poorly understood. A Y163C mutation in the SPINT2 gene encoding the serine protease inhibitor Hepatocyte Growth Factor Inhibitor HAI-2 is associated with a congenital sodium diarrhea. The functional consequences of this mutation on HAI-2 activity and its physiological targets are unknown. We established a cellular assay in Xenopus laevis oocytes to study functional interactions between HAI-2 and candidate membrane-bound serine proteases expressed in the gastro-intestinal tract. We found that the wild-type form of HAI-2 is a potent inhibitor of nine gastro-intestinal serine proteases. The Y163C mutation in the second Kunitz domain of HAI-2 resulted in a complete loss of inhibitory activity on two intestinal proteases, prostasin and tmprss13. The effect of the mutation of the homologous Y68C in the first Kunitz domain of HAI-2 is consistent with a differential contribution of the two Kunitz domains of HAI-2 in the inhibition of serine proteases. By contrast to the Tyr to Cys, the Tyr to Ser substitution did not change the inhibitory potency of HAI-2, indicating that the thiol-group of the cysteine rather than the Tyr deletion is responsible for the HAI-2 loss of function. Our functional assay allowed us to identify membrane-bound serine proteases as cellular target for inhibition by HAI-2 wild type and mutants, and to better define the role of the Tyr in the second Kunitz domain in the inhibitory activity of HAI-2. PMID:24722141

  15. Functional analysis of a missense mutation in the serine protease inhibitor SPINT2 associated with congenital sodium diarrhea.

    Directory of Open Access Journals (Sweden)

    Nicolas Faller

    Full Text Available Membrane-bound serine proteases play important roles in different biological processes. Their regulation by endogenous inhibitors is poorly understood. A Y163C mutation in the SPINT2 gene encoding the serine protease inhibitor Hepatocyte Growth Factor Inhibitor HAI-2 is associated with a congenital sodium diarrhea. The functional consequences of this mutation on HAI-2 activity and its physiological targets are unknown. We established a cellular assay in Xenopus laevis oocytes to study functional interactions between HAI-2 and candidate membrane-bound serine proteases expressed in the gastro-intestinal tract. We found that the wild-type form of HAI-2 is a potent inhibitor of nine gastro-intestinal serine proteases. The Y163C mutation in the second Kunitz domain of HAI-2 resulted in a complete loss of inhibitory activity on two intestinal proteases, prostasin and tmprss13. The effect of the mutation of the homologous Y68C in the first Kunitz domain of HAI-2 is consistent with a differential contribution of the two Kunitz domains of HAI-2 in the inhibition of serine proteases. By contrast to the Tyr to Cys, the Tyr to Ser substitution did not change the inhibitory potency of HAI-2, indicating that the thiol-group of the cysteine rather than the Tyr deletion is responsible for the HAI-2 loss of function. Our functional assay allowed us to identify membrane-bound serine proteases as cellular target for inhibition by HAI-2 wild type and mutants, and to better define the role of the Tyr in the second Kunitz domain in the inhibitory activity of HAI-2.

  16. Three cases of congenital dysfibrinogenemia in unrelated Chinese families: heterozygous missense mutation in fibrinogen alpha chain Argl6His.

    Science.gov (United States)

    Luo, Meiling; Deng, Donghong; Xiang, Liqun; Cheng, Peng; Liao, Lin; Deng, Xuelian; Yan, Jie; Lin, Faquan

    2016-09-01

    Congenital dysfibrinogenemia (CD) is a qualitative fibrinogen disorder caused by an abnormal fibrinogen molecule structure, leading to dysfunctional blood coagulation. This study describes 3 cases of dysfibrinogenemia identified in the unrelated Chinese pedigrees.Routine coagulation screening tests were performed on the probands and their families. The antigens and functionality of fibrinogen was measured using an immunoturbidimetry assay and the Clauss method, respectively. To identify the genetic mutation responsible for these dysfibrinogens, genomic DNA extracted from the blood was analyzed using PCR amplification and direct sequencing. The presence of the mutant chains was determined using matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectroscopy. Purified plasma fibrinogen of 3 probands was analyzed using SDS-PAGE, fibrinogen clottability, fibrin polymerization, fibrinopeptide release, and scanning electron microscopy (SEM).The 3 probands had a long thrombin time. Levels of functional fibrinogen were found to be very low, while the fibrinogen antigen was within the normal range. DNA sequencing revealed a heterozygous Arg16His substitution in the fibrinogen Aα chain (FGA). The mutant chains were found to be expressed using MALDI-TOF mass spectroscopy. SDS-PAGE did not reveal any difference in the molecular weights of 3 polypeptide chains between normal and abnormal fibrinogens. Fibrinogen clottability showed a slower fibrin clot formation than the healthy control. Fibrin polymerization, after addition of thrombin, showed a prolonged lag phase and decreased final turbidity. The kinetics of fibrinopeptides release revealed a decreased amount of the released fibrinopeptide A. SEM of the patient's fibrin clot was found to be abnormal.Results indicate that the 3 probands with dysfibrinogenemia were caused by mutations of Aα chain Arg16His. Mutation of this fibrinogen induced dysfunction of plasma fibrinogen.

  17. A novel missense mutation (G43S) in the switch I region of Rab27A causing Griscelli syndrome

    DEFF Research Database (Denmark)

    Westbroek, W.; Tuchman, M.; Tinloy, B.

    2008-01-01

    steps within cells. In melanocytes, the GTP-bound form of Rab27A associates with the membranes of mature fully-pigmented melanosomes through its geranylgeranyl group. Once attached, Rab27A recruits the downstream effector Melanophilin (Mlph) and the actin-dependent motor protein Myosin Va (Myo...... GSII patient. Laser scanning confocal microscopy showed that the G43S mutation, which is located in the highly conserved switch I region of Rab27A, induces perinuclear localization of melanosomes in normal melanocytes, and fails to restore melanosomes to the actin-rich periphery in GSII melanocytes. Co...

  18. A novel missense mutation of COL5A2 in a patient with Ehlers–Danlos syndrome

    Science.gov (United States)

    Watanabe, Miki; Nakagawa, Ryuji; Naruto, Takuya; Kohmoto, Tomohiro; Suga, Ken-ichi; Goji, Aya; Kagami, Shoji; Masuda, Kiyoshi; Imoto, Issei

    2016-01-01

    Ehlers–Danlos syndrome (EDS) is a group of inherited connective tissue disorders characterized by hyperextensible skin, joint hypermobility and soft tissue fragility. For molecular diagnosis, targeted exome sequencing was performed on a 9-year-old male patient who was clinically suspected to have EDS. The patient presented with progressive kyphoscoliosis, joint hypermobility and hyperextensible skin without scars. Ultimately, classical EDS was diagnosed by identifying a novel, mono-allelic mutation in COL5A2 [NM_000393.3(COL5A2_v001):c.682G>A, p.Gly228Arg]. PMID:27656288

  19. A novel missense mutation of COL5A2 in a patient with Ehlers-Danlos syndrome.

    Science.gov (United States)

    Watanabe, Miki; Nakagawa, Ryuji; Naruto, Takuya; Kohmoto, Tomohiro; Suga, Ken-Ichi; Goji, Aya; Kagami, Shoji; Masuda, Kiyoshi; Imoto, Issei

    2016-01-01

    Ehlers-Danlos syndrome (EDS) is a group of inherited connective tissue disorders characterized by hyperextensible skin, joint hypermobility and soft tissue fragility. For molecular diagnosis, targeted exome sequencing was performed on a 9-year-old male patient who was clinically suspected to have EDS. The patient presented with progressive kyphoscoliosis, joint hypermobility and hyperextensible skin without scars. Ultimately, classical EDS was diagnosed by identifying a novel, mono-allelic mutation in COL5A2 [NM_000393.3(COL5A2_v001):c.682G>A, p.Gly228Arg].

  20. Alternative splicing of exon 17 and a missense mutation in exon 20 of the insulin receptor gene in two brothers with a novel syndrome of insulin resistance (congenital fiber-type disproportion myopathy)

    DEFF Research Database (Denmark)

    Vorwerk, P; Christoffersen, C T; Müller, J

    1999-01-01

    domain. In the correct spliced variant, the point mutation is silent and results in a normally translated IR. The paternal allele carries a missense mutation in the tyrosine kinase domain. All three cDNA variants were present in the lymphocytes of the patients. Purified IR from 293 cells overexpressing...... to be compound heterozygotes for mutations in the IR gene. The maternal allele was alternatively spliced in exon 17 due to a point mutation in the -1 donor splice site of the exon. The abnormal skipping of exon 17 shifts the amino acid reading frame and leads to a truncated IR, missing the entire tyrosine kinase...... either of the two mutated receptors lacked basal or stimulated IR beta-subunit autophosphorylation. A third brother who inherited both normal alleles has an normal muscle phenotype and insulin sensitivity, suggesting a direct linkage of these IR mutations with the CFTDM phenotype....

  1. A missense mutation in TMEM67 causes Meckel-Gruber syndrome type 3 (MKS3): a family from China.

    Science.gov (United States)

    Zhang, Manli; Cheng, Jing; Liu, Aijun; Wang, Longxia; Xiong, Lihua; Chen, Meixia; Sun, Yi; Li, Jianzhong; Lu, Yu; Yuan, Huijun; Li, Yali; Lu, Yanping

    2015-01-01

    Meckel-Gruber syndrome (MKS) is a lethal autosomal recessive condition characterized by renal cysts and variably associated features, including developmental anomalies of the central nervous system (typically encephalocele), hepatic ductal dysplasia and cysts, and polydactyly. Genetic heterogeneity has been demonstrated at eleven loci, MKS1-11. Here, we present the clinical and molecular characteristics of a Chinese MKS3 family with occipital encephalocele and kidney enlargement. DNA sequencing of affected fetuses revealed a homozygous c.1645C>T substitution in exon 16 of TMEM67, leading to a p.R549C substitution in meckelin. The R549 residue is highly conserved across human, rat, mouse, zebrafish, chicken, wolf and platypus genomes. Hha I restriction analysis demonstrated that the c.1645C>T mutation was absent in 200 unrelated control chromosomes of Chinese background, supporting the hypothesis that it represents causative mutation, not rare polymorphism. Our data provide additional molecular and clinical information for establishing a better genotype-phenotype understanding of MKS.

  2. Using diverse U.S. beef cattle genomes to identify missense mutations in EPAS1, a gene associated with pulmonary hypertension [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Michael P. Heaton

    2016-10-01

    Full Text Available The availability of whole genome sequence (WGS data has made it possible to discover protein variants in silico. However, existing bovine WGS databases do not show data in a form conducive to protein variant analysis, and tend to under represent the breadth of genetic diversity in global beef cattle. Thus, our first aim was to use 96 beef sires, sharing minimal pedigree relationships, to create a searchable and publicly viewable set of mapped genomes relevant for 19 popular breeds of U.S. cattle. Our second aim was to identify protein variants encoded by the bovine endothelial PAS domain-containing protein 1 gene (EPAS1, a gene associated with pulmonary hypertension in Angus cattle. The identity and quality of genomic sequences were verified by comparing WGS genotypes to those derived from other methods. The average read depth, genotype scoring rate, and genotype accuracy exceeded 14, 99%, and 99%, respectively. The 96 genomes were used to discover four amino acid variants encoded by EPAS1 (E270Q, P362L, A671G, and L701F and confirm two variants previously associated with disease (A606T and G610S. The six EPAS1 missense mutations were verified with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry assays, and their frequencies were estimated in a separate collection of 1154 U.S. cattle representing 46 breeds. A rooted phylogenetic tree of eight polypeptide sequences provided a framework for evaluating the likely order of mutations and potential impact of EPAS1 alleles on the adaptive response to chronic hypoxia in U.S. cattle. This public, whole genome resource facilitates in silico identification of protein variants in diverse types of U.S. beef cattle, and provides a means of translating WGS data into a practical biological and evolutionary context for generating and testing hypotheses.

  3. Pathologic and phenotypic alterations in a mouse expressing a connexin47 missense mutation that causes Pelizaeus-Merzbacher-like disease in humans.

    Directory of Open Access Journals (Sweden)

    Oliver Tress

    2011-07-01

    Full Text Available Gap junction channels are intercellular conduits that allow diffusional exchange of ions, second messengers, and metabolites. Human oligodendrocytes express the gap junction protein connexin47 (Cx47, which is encoded by the GJC2 gene. The autosomal recessive mutation hCx47M283T causes Pelizaeus-Merzbacher-like disease 1 (PMLD1, a progressive leukodystrophy characterized by hypomyelination, retarded motor development, nystagmus, and spasticity. We introduced the human missense mutation into the orthologous position of the mouse Gjc2 gene and inserted the mCx47M282T coding sequence into the mouse genome via homologous recombination in embryonic stem cells. Three-week-old homozygous Cx47M282T mice displayed impaired rotarod performance but unchanged open-field behavior. 10-15-day-old homozygous Cx47M282T and Cx47 null mice revealed a more than 80% reduction in the number of cells participating in glial networks after biocytin injections into oligodendrocytes in sections of corpus callosum. Homozygous expression of mCx47M282T resulted in reduced MBP expression and astrogliosis in the cerebellum of ten-day-old mice which could also be detected in Cx47 null mice of the same age. Three-month-old homozygous Cx47M282T mice exhibited neither altered open-field behavior nor impaired rotarod performance anymore. Adult mCx47M282T expressing mice did not show substantial myelin alterations, but homozygous Cx47M282T mice, additionally deprived of connexin32, which is also expressed in oligodendrocytes, died within six weeks after birth and displayed severe myelin defects accompanied by astrogliosis and activated microglia. These results strongly suggest that PMLD1 is caused by the loss of Cx47 channel function that results in impaired panglial coupling in white matter tissue.

  4. [Missense mutation R1345Q in CACNA1A gene causes a new type of ataxia with episodic tremor: clinical features, genetic analysis and treatment in a familial case].

    Science.gov (United States)

    Jiang, Hai-Shan; Wang, Dong-Mei; Wang, Qun; Yang, Man; Wang, Wei; Pan, Su-Yue; Hu, Ya-Fang

    2016-06-20

    Mutations in CACNA1A, which encodes the P/Q-type calcium channel subunit, are responsible for at least 3 allelic diseases, namely type 2 episodic ataxia (EA-2), familial hemiplegic migraine?type-1 (FHM1), and spinocerebellar ataxia type-6?(SCA 6). Herein we present a case of ataxia with episodic tremors in a 19-year-old man with a missense mutation of CACNA1A gene and summarize the clinical features, genetic analysis and treatment in this case and in his affected family members. Physical examinations were conducted for the patient and his affected family members. DNA sample from the proband was analyzed with next-generation sequencing technology to identify the causative mutation. Sanger sequencing was used to confirm the gene mutation in the family members. Physical examinations of the patient revealed signs of ataxia, drunken gait, and tremor of his head and body. Four other members in his family had similar but much milder symptoms. A heterozygous missense mutation in CACNA1A (NM_001127221.1 c.4034G->A, p.R1345Q, exon 25) was identified in the proband, which was confirmed in the affected family members. The proband did not respond to methazolamide treatment, but his tremor symptom was well controlled with flunarizine, a calcium channel blocker. Based on the clinical features, mutation analysis and treatment response, we suggest that this patient with a missense CACNA1A mutation, R1345Q, has a new type of ataxia with episodic tremor other than any of EA2, FHM1, or SCA 6.

  5. An integrated computational approach can classify VHL missense mutations according to risk of clear cell Renal carcinoma

    OpenAIRE

    Gossage, Lucy; Pires, Douglas E.V.; Olivera-Nappa, Álvaro; Asenjo,Juan A.; Bycroft, Mark; Blundell, Tom L.; Eisen, Tim

    2014-01-01

    This is the final published version, also available from the publisher website at at: http://hmg.oxfordjournals.org/content/early/2014/06/26/hmg.ddu321.long Mutations in the von Hippel‐Lindau (VHL) gene are pathogenic in VHL disease, congenital  polycythaemia and clear cell renal carcinoma. pVHL forms a ternary complex with Elongin C  and Elongin B, critical for pVHL stability and function, which interacts with Cullin‐2 and  RING‐box protein 1 to target Hypoxia‐inducible factor fo...

  6. Consequences of two naturally occurring missense mutations in the structure and function of Bruton agammaglobulinemia tyrosine kinase.

    Science.gov (United States)

    Vargas-Hernández, Alexander; López-Herrera, Gabriela; Maravillas-Montero, José L; Vences-Catalán, Felipe; Mogica-Martínez, Dolores; Rojo-Domínguez, Arturo; Espinosa-Rosales, Francisco J; Santos-Argumedo, Leopoldo

    2012-04-01

    Bruton agammaglobulinemia tyrosine kinase (BTK) is a key protein in the B-cell receptor (BCR) signaling pathway and plays an essential role in the differentiation of B lymphocytes. X-linked agammaglobulinemia (XLA) is a primary humoral immunodeficiency caused by mutations in the gene encoding BTK. Previously, we identified two novel variations, L111P and E605G, in BTK; these are localized within the pleckstrin homology and Src homology 1 domains, respectively. In the present study, we evaluated the potential effects of these variations on the structural conformation and the function of BTK. Using in silico methods, we found that the L111P and E650G variations are not located directly in protein-protein interfaces but close to them. They distorted the native structural conformation of the BTK protein, affecting not only its geometry and stability but also its ability for protein recognition and in consequence its functionality. To confirm the results of the in silico assays, WT BTK, L111P, and E650G variants were expressed in the BTK-deficient DT40 cell line. The mutant proteins exhibited an absence of catalytic activity, aberrant redistribution after BCR-crosslinking, and deficient intracellular calcium mobilization. This work demonstrates that L111 and E605 residues are fundamental for the activation and function of BTK.

  7. A novel missense mutation pattern of the GCH1 gene in dopa-responsive dystonia Novo padrão de mutação missense no gene GCH1 na distonia dopa-responsiva

    Directory of Open Access Journals (Sweden)

    Rosana H. Scola

    2007-12-01

    Full Text Available Dopa-responsive dystonia (DRD is an inherited metabolic disorder now classified as DYT5 with two different biochemical defects: autosomal dominant GTP cyclohydrolase 1 (GCH1 deficiency or autosomal recessive tyrosine hydroxylase deficiency. We report the case of a 10-years-old girl with progressive generalized dystonia and gait disorder who presented dramatic response to levodopa. The phenylalanine to tyrosine ratio was significantly higher after phenylalanine loading test. This condition had two different heterozygous mutations in the GCH1 gene: the previously reported P23L mutation and a new Q182E mutation. The characteristics of the DRD and the molecular genetic findings are discussed.Distonia dopa-responsiva (DRD, classificada como DYT5, é um erro inato do metabolismo que pode ser causado por dois diferentes tipos de defeito bioquímico: deficiência de GTP ciclo-hidrolase 1 (GCH1 (autossômica dominante ou de tirosina hidroxilase (autossômica recessiva. Descrevemos o caso de menina de 10 anos com distonia generalizada progressiva e alteração da marcha com importante melhora após uso de levodopa. A relação fenilalanina/tirosina estava aumentada após teste de sobrecarga com fenilalanina. O estudo molecular mostrou que o paciente apresenta uma combinação hererozigótica de mutação no gene GCH1: a já conhecida mutação P23L e uma nova mutação Q182E. Discutem-se as características da DRD e as alterações genéticas possíveis.

  8. Missense mutations (p.H371Y, p.D438Y) in gene CHEK2 are associated with breast cancer risk in women of Balochistan origin.

    Science.gov (United States)

    Baloch, Abdul Hameed; Daud, Shakeela; Raheem, Nafeesa; Luqman, Muhammad; Ahmad, Adeel; Rehman, Abdul; Shuja, Jameela; Rasheed, Saeeda; Ali, Akhtar; Kakar, Naseebullah; Naseeb, Hafiz Khush; Mengal, Mohammad Alam; Awan, Muhammad Arif; Wasim, Muhammad; Baloch, Dost Mohammad; Ahmad, Jamil

    2014-02-01

    CHEK2 encodes a serine/threonine-protein kinase which plays a critical role in DNA damage signaling pathways. CHEK2 directly phosphorylates and regulates the functions of p53 and BRCA1. Most women with breast and/or ovarian cancer are not carriers of mutant BRCA1 or BRCA2. Multiple studies have shown that a CHEK2*1100delC confers about a two-fold increased risk of breast cancer in unselected females and a tenfold increase in males. Moreover, studies have shown that first-degree relatives of bilateral breast cancer cases who carried the CHEK2*1100delC allele had an eight-fold increased risk of breast cancer. It has been suggested that CHEK2 functions as a low-penetrance susceptibility gene for cancers and multiplies the risks associated with other gene(s) to increase cancer risk. The main goal of this study was to evaluate and to compare the role of truncating mutations, splice junction mutations and rare missense substitutions in breast cancer susceptibility gene CHEK2. Present study was performed on 140 individuals including 70 breast cancer patients both with and without family history and 70 normal individuals. Written consent was obtained and 3 ml intravenous blood was drawn from all the subjects. DNA was extracted from all the samples through inorganic method published already. Primers were synthesized for all the 14 exons of CHEK2 gene. Coding and adjacent intronic sequences of CHEK2 gene were amplified and sequenced. Two genetic variants (p.H371Y, p.D438Y) were found in exon 10 and exon 11 of gene CHEK2 which were not found in any of the 70 control individuals from same geographical area and ethnic group. The genetic variant c.1312G>T (p.D438Y) identified in a patient with a family history of breast cancer. To our knowledge, this is first mutation scanning study of gene CHEK2 from Balochistan population.

  9. A Missense Mutation in SLC45A2 Is Associated with Albinism in Several Small Long Haired Dog Breeds.

    Science.gov (United States)

    Wijesena, Hiruni R; Schmutz, Sheila M

    2015-01-01

    Homozygosity for a large deletion in the solute carrier family 45, member 2 (SLC45A2) gene causes oculocutaneous albinism (OCA) in the Doberman Pinscher breed. An albino Lhasa Apso did not have this g.27141_31223del (CanFam2) deletion in her SLC45A2 sequence. Therefore, SLC45A2 was investigated in this female Lhasa Apso to search for other possible variants that caused her albinism. The albino Lhasa Apso was homozygous for a nonsynonymous substitution in the seventh exon, a c.1478G>A base change that resulted in a glycine to aspartic acid substitution (p.G493D). This mutation was not found in a wolf, a coyote, or any of the 15 other Lhasa Apso dogs or 32 other dogs of breeds related to the Lhasa Apso. However, an albino Pekingese, 2 albino Pomeranians, and an albino mixed breed dog that was small and long haired were also homozygous for the 493D allele. The colored puppies of the albino Lhasa Apso and the colored dam of the 2 albino Pomeranians were heterozygous for this allele. However, an albino Pug was homozygous for the 493G allele and therefore although we suggest the 493D allele causes albinism when homozygous in several small, long haired dog breeds, it does not explain all albinism in dogs. A variant effect prediction for the albino Lhasa Apso confirms that p.G493D is a deleterious substitution, and a topology prediction for SLC45A2 suggests that the 11th transmembrane domain where the 493rd amino acid was located, has an altered structure.

  10. Missense mutations in PBP2A Affecting ceftaroline susceptibility detected in epidemic hospital-acquired methicillin-resistant Staphylococcus aureus clonotypes ST228 and ST247 in Western Switzerland archived since 1998.

    Science.gov (United States)

    Kelley, William L; Jousselin, Ambre; Barras, Christine; Lelong, Emmanuelle; Renzoni, Adriana

    2015-04-01

    The development and maintenance of an arsenal of antibiotics is a major health care challenge. Ceftaroline is a new cephalosporin with activity against methicillin-resistant Staphylococcus aureus (MRSA); however, no reports concerning MRSA ceftaroline susceptibility have been reported in Switzerland. We tested the in vitro activity of ceftaroline against an archived set of 60 MRSA strains from the University Hospital of Geneva collected from 1994 to 2003. Our results surprisingly revealed ceftaroline-resistant strains (MIC, >1 μg/ml in 40/60 strains; EUCAST breakpoints, susceptible [S], ≤1 μg/ml; resistant [R], >1 μg/ml) were present from 1998 to 2003. The detected resistant strains predominantly belonged to sequence type 228 (ST228) (South German clonotype) but also to ST247 (Iberian clonotype). A sequence analysis of these strains revealed missense mutations in the penicillin-binding protein 2A (PBP2A) allosteric domain (N146K or E239K and N146K-E150K-G246E). The majority of our ST228 PBP2A mutations (N146K or E150K) were distinct from ST228 PBP2A allosteric domain mutations (primarily E239K) recently described for MRSA strains collected in Thailand and Spain during the 2010 Assessing Worldwide Antimicrobial Resistance Evaluation (AWARE) global surveillance program. We also found that similar allosteric domain PBP2A mutations (N146K) correlated with ceftaroline resistance in an independent external ST228 MRSA set obtained from the nearby University Hospital of Lausanne, Lausanne, Switzerland, collected from 2003 to 2008. Thus, ceftaroline resistance was observed in our archived strains (including two examples of an MIC of 4 µg/ml for the Iberian ST247 clonotype with the triple mutation N146K/E150K/G246E), at least as far back as 1998, considerably predating the commercial introduction of ceftaroline. Our results reinforce the notion that unknown parameters can potentially exert selective pressure on PBP2A that can subsequently modulate ceftaroline

  11. Case Report of Birt-Hogg-Dubé Syndrome: Germline Mutations of FLCN Detected in Patients With Renal Cancer and Thyroid Cancer.

    Science.gov (United States)

    Dong, Li; Gao, Ming; Hao, Wei-Jing; Zheng, Xiang-Qian; Li, Yi-Gong; Li, Xiao-Long; Yu, Yang

    2016-05-01

    Birt-Hogg-Dubé (BHD) is a rare autosomal dominant inherited syndrome that is characterized by the presence of fibrofolliculomas and/or trichodiscomas, pulmonary cysts, spontaneous pneumothorax, and renal tumors. Here, the 2 patients we reported with renal cell carcinomas and dermatological features were suspected to be suffering from BHD syndrome. Blood samples of these patients were sent for whole exon sequencing performed by Sanger sequencing. Eight mutations, including 5 mutations, which were mapped in noncoding region, 1 synonymous mutation, and 2 missense mutations, were detected in the FLCN gene in both patients. The 2 missense mutations, predicted to be disease-causing mutation or affecting protein function by MutationTaster and SIFT, confirmed the diagnosis. In addition, the 2 patients were also affected with papillary thyroid cancer. Total thyroidectomy and prophylactic bilateral central lymph node dissection were performed for them and the BHD-2 also received lateral lymph node dissection. Pathology reports showed that the patients had lymph node metastasis in spite of small size of thyroid lesions.The 2 missense mutations, not reported previously, expand the mutation spectrum of FLCN gene associated with BHD syndrome. For the thyroid cancer patients with BHD syndrome, total thyroidectomy and prophylactic bilateral central lymph node dissection may be suitable and the neck ultrasound may benefit BHD patients and their family members.

  12. Severe G6PD Deficiency Due to a New Missense Mutation in an Infant of Northern European Descent

    DEFF Research Database (Denmark)

    Warny, Marie; Lausen, Birgitte; Birgens, Henrik

    2015-01-01

    We report a term male infant born to parents of Danish descent, who on the second day of life developed jaundice peaking at 67 hours and decreasing on applied double-sided phototherapy. In the weeks following, the infant showed signs of ongoing hemolysis. Laboratory tests showed very low glucose-...

  13. A novel missense mutation, GGC(Arg454)→TGC(Cys), of CYP11B1 gene identified in a Chinese family with steroid 11β-hydroxylase deficiency

    Institute of Scientific and Technical Information of China (English)

    YE Zheng-qin; ZHANG Man-na; ZHANG Hui-jie; JIANG Jing-jing; LI Xiao-ying; ZHANG Ke-qin

    2010-01-01

    Background Steroid 11β-hydroxylase deficiency (11β-OHD), an autosomal recessive inherited disease, accounts for 5%-8% of congenital adrenal hyperplasia.It was scarcely reported in China.This article reports two Chinese girls with 11β-OHD.Methods The two patients were sisters and presented with hypertrichosis, skin pigmentation, laryngeal prominence and virilization of external genitalia.The patients were followed up for their clinical symptoms and signs, hormone profile,and adrenal image.The genomic deoxyribonucleic acids of the patients and their parents were isolated.11β-hydroxylase gene (CYP11B1) was amplified by polymerase chain reaction and directly sequenced.Results Hormone tests showed that serum cortisol was in the low limit of normal range, whereas the concentrations of adrenocorticotropic hormone, testosterone and progesterone were much higher than those of normal adult females.There were obvious adrenal hyperplasia and advance of bone age.After 11 months of treatment with dexamethasone,the skin pigment became regressed; the breast, uterus and ovary gradually developed and normal menstrual cycle started while the manifestations of virilization did not change.A single point mutation of CYP11B1 (R454C, GGC → TGC)in all the members of this family was detected.The sisters were homozygous and their parents were heterozygous.Conclusions The clinical manifestation of 11β-OHD is complicated.The manifestation of virilization could not regress after treatment with dexamethasone.The novel missense mutation of CYP11B1 (R454C, GGC → TGC) is the pathogenesis of 11β-OHD at least in some Chinese patients.

  14. Increased rate of missense/in-frame mutations in individuals with NF1-related pulmonary stenosis: a novel genotype-phenotype correlation.

    Science.gov (United States)

    Ben-Shachar, Shay; Constantini, Shlomi; Hallevi, Hen; Sach, Emma K; Upadhyaya, Meena; Evans, Gareth D; Huson, Susan M

    2013-05-01

    Neurofibromatosis type 1 (NF1) and its related disorders (NF1-Noonan syndrome (NFNS) and Watson syndrome (WS)) are caused by heterozygous mutations in the NF1 gene. Pulmonary stenosis (PS) occurs more commonly in NF1 and its related disorders than in the general population. This study investigated whether PS is associated with specific types of NF1 gene mutations in NF1, NFNS and WS. The frequency of different NF1 mutation types in a cohort of published and unpublished cases with NF1/NFNS/WS and PS was examined. Compared with NF1 in general, NFNS patients had higher rates of PS (9/35=26% vs 25/2322=1.1%, P valueNF1 in general (PNF1 and PS, were found to have non-truncating mutations, a much higher frequency than the 19% reported in NF1 cohorts (PNF1 and its related disorders is clearly associated with non-truncating mutations in the NF1 gene providing a new genotype-phenotype correlation. The data indicate a specific role of non-truncating mutations on the NF1 cardiac phenotype.

  15. Short communication: A missense mutation in the PROP1 (prophet of Pit 1) gene affects male fertility and milk production traits in the US Holstein population.

    Science.gov (United States)

    Lan, X Y; Peñagaricano, F; DeJung, L; Weigel, K A; Khatib, H

    2013-02-01

    In previous studies, we reported significant associations of the POU1F1 pathway genes with reproduction and production traits in several dairy cattle populations. Polymorphisms in genes of this pathway were found to be associated with both female and male fertility traits in dairy cattle. The POU1F1 gene is a direct downstream target for the regulation of the prophet of Pit1 (PROP1) gene, also known as PROP paired-like homeobox 1. Interestingly, the position of PROP1 coincides with a quantitative trait locus affecting ovulation rate in cattle. Therefore, the objective of this study was to investigate whether PROP1 affects fertility and milk production traits in Holstein cattle. Using the DNA pooling sequencing approach, a missense single nucleotide polymorphism that replaces a histidine amino acid with an arginine was detected in exon 3 of PROP1. The arginine allele was found to be associated with a decrease in sire conception rate and an increase in productive life, protein yield, and net merit index in a population of 1,951 Holstein bulls. The transcription factors produced from the histidine and arginine isoforms are known to have different transcription, DNA binding, and regulation activities. As such, we propose that the association of the arginine isoform with decreased bull fertility is likely caused by reduced activity of this allele in male functions. The findings of this study suggest PROP1 polymorphisms as candidates in selection programs for fertility, health, and milk production traits in dairy cattle.

  16. The prevalence of CHD7 missense versus truncating mutations is higher in patients with Kallmann syndrome than in typical CHARGE patients

    DEFF Research Database (Denmark)

    Marcos, Séverine; Sarfati, Julie; Leroy, Chrystel

    2014-01-01

    CONTEXT: Mutations in CHD7, a gene previously implicated in CHARGE (coloboma, heart defect, choanal atresia, retardation of growth and/or development, genital hypoplasia, ear anomalies) syndrome, have been reported in patients presenting with Kallmann syndrome (KS) or congenital hypogonadotropic ...... in this gene in KS patients seeking fertility treatment, especially if KS is associated with deafness and cleft lip/palate........ Thus, the clinical spectrum associated with CHD7 mutations may be partly explained by genotype/phenotype correlations. Eight patients also had congenital deafness and one had a cleft lip/palate, whereas six had both. For 10 patients, the presence of diverse features of the CHARGE spectrum in at least...

  17. Missense Mutation of Brain Derived Neurotrophic Factor (BDNF Alters Neurocognitive Performance in Patients with Mild Traumatic Brain Injury: A Longitudinal Study.

    Directory of Open Access Journals (Sweden)

    Vairavan Narayanan

    Full Text Available The predictability of neurocognitive outcomes in patients with traumatic brain injury is not straightforward. The extent and nature of recovery in patients with mild traumatic brain injury (mTBI are usually heterogeneous and not substantially explained by the commonly known demographic and injury-related prognostic factors despite having sustained similar injuries or injury severity. Hence, this study evaluated the effects and association of the Brain Derived Neurotrophic Factor (BDNF missense mutations in relation to neurocognitive performance among patients with mTBI. 48 patients with mTBI were prospectively recruited and MRI scans of the brain were performed within an average 10.1 (SD 4.2 hours post trauma with assessment of their neuropsychological performance post full Glasgow Coma Scale (GCS recovery. Neurocognitive assessments were repeated again at 6 months follow-up. The paired t-test, Cohen's d effect size and repeated measure ANOVA were performed to delineate statistically significant differences between the groups [wildtype G allele (Val homozygotes vs. minor A allele (Met carriers] and their neuropsychological performance across the time point (T1 = baseline/ admission vs. T2 = 6th month follow-up. Minor A allele carriers in this study generally performed more poorly on neuropsychological testing in comparison wildtype G allele group at both time points. Significant mean differences were observed among the wildtype group in the domains of memory (M = -11.44, SD = 10.0, p = .01, d = 1.22, executive function (M = -11.56, SD = 11.7, p = .02, d = 1.05 and overall performance (M = -6.89 SD = 5.3, p = .00, d = 1.39, while the minor A allele carriers showed significant mean differences in the domains of attention (M = -11.0, SD = 13.1, p = .00, d = .86 and overall cognitive performance (M = -5.25, SD = 8.1, p = .01, d = .66.The minor A allele carriers in comparison to the wildtype G allele group, showed considerably lower scores at

  18. Homozygous missense mutation (G56R in glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPI-HBP1 in two siblings with fasting chylomicronemia (MIM 144650

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    Hegele Robert A

    2007-09-01

    Full Text Available Abstract Background Mice with a deleted Gpihbp1 gene encoding glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPI-HBP1 develop severe chylomicronemia. We screened the coding regions of the human homologue – GPIHBP1 – from the genomic DNA of 160 unrelated adults with fasting chylomicronemia and plasma triglycerides >10 mmol/L, each of whom had normal sequence of the LPL and APOC2 genes. Results One patient with severe type 5 hyperlipoproteinemia (MIM 144650, fasting chylomicronemia and relapsing pancreatitis resistant to standard therapy was found to be homozygous for a novel GPIHBP1 missense variant, namely G56R. This mutation was absent from the genomes of 600 control subjects and 610 patients with hyperlipidemia. The GPIHBP1 G56 residue has been conserved throughout evolution and the G56R mutation was predicted to have compromised function. Her homozygous brother also had refractory chylomicronemia and relapsing pancreatitis together with early coronary heart disease. G56R heterozygotes in the family had fasting mild hypertriglyceridemia. Conclusion Thus, a very rare GPIHBP1 missense mutation appears to be associated with severe hypertriglyceridemia and chylomicronemia.

  19. Progressive Purkinje cell degeneration in tambaleante mutant mice is a consequence of a missense mutation in HERC1 E3 ubiquitin ligase.

    Directory of Open Access Journals (Sweden)

    Tomoji Mashimo

    2009-12-01

    Full Text Available The HERC gene family encodes proteins with two characteristic domains: HECT and RCC1-like. Proteins with HECT domains have been described to function as ubiquitin ligases, and those that contain RCC1-like domains have been reported to function as GTPases regulators. These two activities are essential in a number of important cellular processes such as cell cycle, cell signaling, and membrane trafficking. Mutations affecting these domains have been found associated with retinitis pigmentosa, amyotrophic lateral sclerosis, and cancer. In humans, six HERC genes have been reported which encode two subgroups of HERC proteins: large (HERC1-2 and small (HERC3-6. The giant HERC1 protein was the first to be identified. It has been involved in membrane trafficking and cell proliferation/growth through its interactions with clathrin, M2-pyruvate kinase, and TSC2 proteins. Mutations affecting other members of the HERC family have been found to be associated with sterility and growth retardation. Here, we report the characterization of a recessive mutation named tambaleante, which causes progressive Purkinje cell degeneration leading to severe ataxia with reduced growth and lifespan in homozygous mice aged over two months. We mapped this mutation in mouse chromosome 9 and then performed positional cloning. We found a GA transition at position 1448, causing a Gly to Glu substitution (Gly483Glu in the highly conserved N-terminal RCC1-like domain of the HERC1 protein. Successful transgenic rescue, with either a mouse BAC containing the normal copy of Herc1 or with the human HERC1 cDNA, validated our findings. Histological and biochemical studies revealed extensive autophagy associated with an increase of the mutant protein level and a decrease of mTOR activity. Our observations concerning this first mutation in the Herc1 gene contribute to the functional annotation of the encoded E3 ubiquitin ligase and underline the crucial and unexpected role of this protein

  20. The de novo missense mutation N117S in skeletal muscle α‑actin 1 causes a mild form of congenital nemaline myopathy.

    Science.gov (United States)

    Yang, Liu; Yu, Ping; Chen, Xiang; Cai, Tao

    2016-08-01

    Nemaline myopathy (NM) constitutes a spectrum of primary skeletal muscle disorders, the diagnosis of which is based on muscle weakness and the visualization of nemaline bodies in muscle biopsies. Mutations in several NM causal genes have been attributed to the majority of NM cases, particularly mutations in nebulin and skeletal muscle α‑actin 1 (ACTA1), which are responsible for ~70% of cases; therefore, a genetic diagnostic strategy using targeted gene sequencing may potentially improve the diagnosis of suspected NM. The present study identified a de novo mutation in ACTA1 (c.350A>G; p.Asn117Ser) in a Chinese patient using target‑capture sequencing of a panel containing 125 known causal genes for inherited muscle diseases. Clinical analyses revealed that the case described in the present study exhibited a relatively mild phenotype with regards to muscle weakness, as compared with more severe phenotypes reported in several other patients with the same mutation, thus suggesting the existence of genetic modifiers. In conclusion, this approach may be helpful for the identification of clinically undiagnosed patients with highly heterogeneous disorders.

  1. The Gly482Ser Missense Mutation of the Peroxisome Proliferator-Activated Receptor γ Coactivator-1α (PGC-1α Gene Associates with Reduced Insulin Sensitivity in Normal and Glucose-Intolerant Obese Subjects

    Directory of Open Access Journals (Sweden)

    Marzia Fanelli

    2005-01-01

    Full Text Available Among the putative candidate genes for insulin resistance, the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α is a transcriptional coactivator of PPARγ and α, regulating a wide range of processes involved in energy production and utilization, such as thermogenesis, liver gluconeogenesis, glucose uptake in muscle. In population studies a Gly482Ser substitution in PGC-1α has been reported to be associated with increased risk of type diabetes 2 and insulin resistance. In the present study we have analysed the association between the Gly482Ser missense mutation of the PGC-1α gene and insulin sensitivity and glucose tolerance in a population of obese non-diabetic subjects. The Gly482Ser SNPs was detected by PCR-RFLP in a cohort of 358 Caucasian obese subjects (223 with normal glucose tolerance (NGT and 125 with impaired glucose tolerance (IGT. We observed a significant association (p < 0.007 between carriers of the Gly482Ser variant of the PGC-1α gene and insulin resistance measured by HOMAIR. Multivariate analysis confirmed that the Gly482Ser SNP was a significant (p < 0.02 determinant of decreased insulin sensitivity, independently from other well-known modulators of insulin action. In conclusion, we have found significant association between the Gly482Ser variant of the PGC-1α gene and reduced insulin sensitivity in obese subjects. This association resulted independent from all other known modulators of insulin resistance, and suggests a primary role for the PGC-1α gene on the genetic susceptibility to insulin resistance in obesity.

  2. The Domain II S4-S5 Linker in Nav1.9: A Missense Mutation Enhances Activation, Impairs Fast Inactivation, and Produces Human Painful Neuropathy.

    Science.gov (United States)

    Han, Chongyang; Yang, Yang; de Greef, Bianca T A; Hoeijmakers, Janneke G J; Gerrits, Monique M; Verhamme, Camiel; Qu, Jian; Lauria, Giuseppe; Merkies, Ingemar S J; Faber, Catharina G; Dib-Hajj, Sulayman D; Waxman, Stephen G

    2015-06-01

    Painful small fiber neuropathy is a challenging medical condition with no effective treatment. Non-genetic causes can be identified in one half of the subjects. Gain-of-function variants of sodium channels Nav1.7 and Nav1.8 have recently been associated with painful small fiber neuropathy. More recently, mutations of sodium channel Nav1.9 have been linked to human pain disorders, with two gain-of-function mutations found in patients with painful small fiber neuropathy. Here we report a novel Nav1.9 mutation, a glycine 699 substitution by arginine (G699R) in the domain II S4-S5 linker, identified in a patient with painful small fiber neuropathy. In this study, we assayed the mutant channels by voltage-clamp in superior cervical ganglion neurons, which do not produce endogenous Nav1.8 or Nav1.9 currents, and provide a novel platform where Nav1.9 is expressed at relatively high levels. Voltage-clamp analysis showed that the mutation hyperpolarizes (-10.1 mV) channel activation, depolarizes (+6.3 mV) steady-state fast inactivation, slows deactivation, and enhances ramp responses compared with wild-type Nav1.9 channels. Current-clamp analysis showed that the G699R mutant channels render dorsal root ganglion neurons hyperexcitable, via depolarized resting membrane potential, reduced current threshold and increased evoked firing. These observations show that the domain II S4-S5 linker plays an important role in the gating of Nav1.9 and demonstrates that a mutation in this linker is linked to a common pain disorder.

  3. Alternative splicing of exon 17 and a missense mutation in exon 20 of the insulin receptor gene in two brothers with a novel syndrome of insulin resistance (congenital fiber-type disproportion myopathy).

    Science.gov (United States)

    Vorwerk, P; Christoffersen, C T; Müller, J; Vestergaard, H; Pedersen, O; De Meyts, P

    1999-01-01

    The insulin receptor (IR) in two brothers with a rare syndrome of congenital muscle fiber type disproportion myopathy (CFTDM) associated with diabetes and severe insulin resistance was studied. By direct sequencing of Epstein-Barr virus-transformed lymphocytes both patients were found to be compound heterozygotes for mutations in the IR gene. The maternal allele was alternatively spliced in exon 17 due to a point mutation in the -1 donor splice site of the exon. The abnormal skipping of exon 17 shifts the amino acid reading frame and leads to a truncated IR, missing the entire tyrosine kinase domain. In the correct spliced variant, the point mutation is silent and results in a normally translated IR. The paternal allele carries a missense mutation in the tyrosine kinase domain. All three cDNA variants were present in the lymphocytes of the patients. Purified IR from 293 cells overexpressing either of the two mutated receptors lacked basal or stimulated IR beta-subunit autophosphorylation. A third brother who inherited both normal alleles has an normal muscle phenotype and insulin sensitivity, suggesting a direct linkage of these IR mutations with the CFTDM phenotype.

  4. Splice, insertion-deletion and nonsense mutations that perturb the phenylalanine hydroxylase transcript cause phenylketonuria in India.

    Science.gov (United States)

    Bashyam, Murali D; Chaudhary, Ajay K; Kiran, Manjari; Nagarajaram, Hampapathalu A; Devi, Radha Rama; Ranganath, Prajnya; Dalal, Ashwin; Bashyam, Leena; Gupta, Neerja; Kabra, Madhulika; Muranjan, Mamta; Puri, Ratna D; Verma, Ishwar C; Nampoothiri, Sheela; Kadandale, Jayarama S

    2014-03-01

    Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by mutational inactivation of the phenylalanine hydroxylase (PAH) gene. Missense mutations are the most common PAH mutation type detected in PKU patients worldwide. We performed PAH mutation analysis in 27 suspected Indian PKU families (including 7 from our previous study) followed by structure and function analysis of specific missense and splice/insertion-deletion/nonsense mutations, respectively. Of the 27 families, disease-causing mutations were detected in 25. A total of 20 different mutations were identified of which 7 "unique" mutations accounted for 13 of 25 mutation positive families. The unique mutations detected exclusively in Indian PKU patients included three recurrent mutations detected in three families each. The 20 mutations included only 5 missense mutations in addition to 5 splice, 4 each nonsense and insertion-deletion mutations, a silent variant in coding region and a 3'UTR mutation. One deletion and two nonsense mutations were characterized to confirm significant reduction in mutant transcript levels possibly through activation of nonsense mediated decay. All missense mutations affected conserved amino acid residues and sequence and structure analysis suggested significant perturbations in the enzyme activity of respective mutant proteins. This is probably the first report of identification of a significantly low proportion of missense PAH mutations from PKU families and together with the presence of a high proportion of splice, insertion-deletion, and nonsense mutations, points to a unique PAH mutation profile in Indian PKU patients.

  5. A syndrome of female pseudohermaphrodism, hypergonadotropic hypogonadism, and multicystic ovaries associated with missense mutations in the gene encoding aromatase (P450arom)

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    Conte, F.A.; Grumbach, M.M. [Univ. of California, San Francisco, CA (United States); Ito, Y.; Fisher, C.R.; Simpson, E.R. [Univ. of Texas Southwestern Medical Center, Dallas, TX (United States)

    1994-06-01

    The authors report the features of a new syndrome of aromatase deficiency due to molecular defects in the CYP19 (P450arom) gene in a 46,XX female. At birth, the patient presented with a nonadrenal form of female pseudohermaphrodism. At 17 months of age, laparotomy revealed normal female internal genital structures; the histological appearance of the ovaries was normal. FSH concentrations were markedly elevated at 9.4 ng/mL LER 869, and estrone and estradiol levels were undetectable (<37 pmol/L). By 14 yr of age, she had failed to exhibit breast development. The clitoris has enlarged to 4 x 2 cm, and pubic hair was Tanner stage IV. The plasma concentration of testosterone was elevated at 3294 pmol/L, as was androstenedione at 9951 pmol/L. Plasma estradiol levels were below 37 pmol/L. ACTH and dexamethasone tests indicated a nonadrenal source of testosterone and androstenedione. Plasma gonadotropin levels were in the castrate range. Pelvic sonography and magnetic resonance imaging showed multiple 4- to 6-cm ovarian cysts bilaterally. Despite increased circulating androgens and clitoral growth, the bone age was 10 yr at chronologic age 14 2/12 yr. Estrogen replacement therapy resulted in a growth spurt, breast development, menarche, suppression of gonadotropin levels, and resolution of the cysts. The clinical findings suggested the diagnosis of P450arom deficiency. Analyses of genomic DNA from ovarian fibroblasts demonstrated two single base changes in the coding region of the P450arom gene, one at 1303 basepairs (C-T), R435C, and the other at 1310 basepairs (G-A), C437Y, in exon 10. The molecular genetic studies indicate that the patient is a compound heterozygote for these mutations. Expression of these mutations showed that the R435C mutation had 1.1% the activity of the wild-type P450arom enzyme, whereas the C437Y mutation demonstrated no activity. 32 refs., 6 figs., 2 tabs.

  6. Powdery Mildew Resistance Conferred by Loss of the ENHANCED DISEASE RESISTANCE1 Protein Kinase Is Suppressed by a Missense Mutation in KEEP ON GOING, a Regulator of Abscisic Acid Signaling1[W][OA

    Science.gov (United States)

    Wawrzynska, Anna; Christiansen, Katy M.; Lan, Yinan; Rodibaugh, Natalie L.; Innes, Roger W.

    2008-01-01

    Loss-of-function mutations in the Arabidopsis (Arabidopsis thaliana) ENHANCED DISEASE RESISTANCE1 (EDR1) gene confer enhanced resistance to infection by powdery mildew (Golovinomyces cichoracearum). EDR1 encodes a protein kinase, but its substrates and the pathways regulated by EDR1 are unknown. To identify components of the EDR1 signal transduction pathway(s), we conducted a forward genetic screen for mutations that suppressed edr1-mediated disease resistance. Genetic mapping and cloning of one of these suppressor mutations revealed a recessive missense mutation in the KEEP ON GOING gene (KEG; At5g13530), which we designated keg-4. KEG encodes a multidomain protein that includes a RING E3 ligase domain, a kinase domain, ankyrin repeats, and HERC2-like repeats. The KEG protein has previously been shown to have ubiquitin ligase activity and to negatively regulate protein levels of the transcription factor ABCISIC ACID INSENSITIVE5. KEG mRNA levels were found to be 3-fold higher in edr1 mutant plants compared to wild type. Loss-of-function mutations in KEG are seedling lethal and are hypersensitive to glucose and abscisic acid (ABA). The keg-4 mutation, in contrast, conferred resistance to 6% glucose and suppressed edr1-mediated hypersensitivity to ABA, suggesting that the keg-4 mutation suppresses ABA signaling by altering KEG function. Several ABA-responsive genes were found to be further up-regulated in the edr1 mutant following ABA treatment, and this up-regulation was suppressed by the keg-4 mutation. We conclude that edr1-mediated resistance to powdery mildew is mediated, in part, by enhanced ABA signaling. PMID:18815384

  7. Powdery mildew resistance conferred by loss of the ENHANCED DISEASE RESISTANCE1 protein kinase is suppressed by a missense mutation in KEEP ON GOING, a regulator of abscisic acid signaling.

    Science.gov (United States)

    Wawrzynska, Anna; Christiansen, Katy M; Lan, Yinan; Rodibaugh, Natalie L; Innes, Roger W

    2008-11-01

    Loss-of-function mutations in the Arabidopsis (Arabidopsis thaliana) ENHANCED DISEASE RESISTANCE1 (EDR1) gene confer enhanced resistance to infection by powdery mildew (Golovinomyces cichoracearum). EDR1 encodes a protein kinase, but its substrates and the pathways regulated by EDR1 are unknown. To identify components of the EDR1 signal transduction pathway(s), we conducted a forward genetic screen for mutations that suppressed edr1-mediated disease resistance. Genetic mapping and cloning of one of these suppressor mutations revealed a recessive missense mutation in the KEEP ON GOING gene (KEG; At5g13530), which we designated keg-4. KEG encodes a multidomain protein that includes a RING E3 ligase domain, a kinase domain, ankyrin repeats, and HERC2-like repeats. The KEG protein has previously been shown to have ubiquitin ligase activity and to negatively regulate protein levels of the transcription factor ABCISIC ACID INSENSITIVE5. KEG mRNA levels were found to be 3-fold higher in edr1 mutant plants compared to wild type. Loss-of-function mutations in KEG are seedling lethal and are hypersensitive to glucose and abscisic acid (ABA). The keg-4 mutation, in contrast, conferred resistance to 6% glucose and suppressed edr1-mediated hypersensitivity to ABA, suggesting that the keg-4 mutation suppresses ABA signaling by altering KEG function. Several ABA-responsive genes were found to be further up-regulated in the edr1 mutant following ABA treatment, and this up-regulation was suppressed by the keg-4 mutation. We conclude that edr1-mediated resistance to powdery mildew is mediated, in part, by enhanced ABA signaling.

  8. Alterations of the IKBKG locus and diseases: an update and a report of 13 novel mutations.

    Science.gov (United States)

    Fusco, Francesca; Pescatore, Alessandra; Bal, Elodie; Ghoul, Aida; Paciolla, Mariateresa; Lioi, Maria Brigida; D'Urso, Michele; Rabia, Smail Hadj; Bodemer, Christine; Bonnefont, Jean Paul; Munnich, Arnold; Miano, Maria Giuseppina; Smahi, Asma; Ursini, Matilde Valeria

    2008-05-01

    Mutations in the inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase gamma (IKBKG), also called nuclear factor-kappaB (NF-kB) essential modulator (NEMO), gene are the most common single cause of incontinentia pigmenti (IP) in females and anhydrotic ectodermal dysplasia with immunodeficiency (EDA-ID) in males. The IKBKG gene, located in the Xq28 chromosomal region, encodes for the regulatory subunit of the inhibitor of kappaB (IkB) kinase (IKK) complex required for the activation of the NF-kB pathway. Therefore, the remarkably heterogeneous and often severe clinical presentation reported in IP is due to the pleiotropic role of this signaling transcription pathway. A recurrent exon 4_10 genomic rearrangement in the IKBKG gene accounts for 60 to 80% of IP-causing mutations. Besides the IKBKG rearrangement found in IP females (which is lethal in males), a total of 69 different small mutations (missense, frameshift, nonsense, and splice-site mutations) have been reported, including 13 novel ones in this work. The updated distribution of all the IP- and EDA-ID-causing mutations along the IKBKG gene highlights a secondary hotspot mutation in exon 10, which contains only 11% of the protein. Furthermore, familial inheritance analysis revealed an unexpectedly high incidence of sporadic cases (>65%). The sum of the observations can aid both in determining the molecular basis of IP and EDA-ID allelic diseases, and in genetic counseling in affected families.

  9. A multiple primary carcinoma consisting of leukoplakia and SCC: a case report with p53 mutation analysis.

    Science.gov (United States)

    Hassan, Nur Mohammad Monsur; Tada, Mitsuhiro; Shindoh, Masanobu; Hamada, Jun-Ichi; Kashiwazaki, Haruhiko; Shimo, Tsuyoshi; Ashikaga, Yuichi; Yamazaki, Yutaka; Sasaki, Akira; Moriuchi, Tetsuya; Inoue, Nobuo

    2010-11-01

    Patients with an oral squamous cell carcinoma (OSCC) often develop multiple malignant lesions. This report examined whether individual tumours developed in a patient show the same genetic alteration, such as p53 mutations. This case study describes three SCCs and three leukoplakias which developed simultaneously in a single 67-year-old Japanese man. A p53 mutation was detected in two of the three SCCs and one of the three leukoplakias. One SCC had a missense mutation at codon 285 (GAG>AAG, Glu>Lys) and the other a nonsense mutation at codon 336, and the leukoplakia had a missense mutation at codon 273 (CGT>CAT, Arg>His). This case showed that individual oral tumours may have different genetic changes even when they develop in a single patient. Therefore, this report provided strong evidence that in cases of multiple tumours it is necessary to design tailor-made therapies for each individual tumour rather than a single standardised therapy for all multiple tumours.

  10. Acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome: report of a child with phenotypic overlap with ulnar-mammary syndrome and a new mutation in TP63.

    Science.gov (United States)

    Slavotinek, Anne M; Tanaka, June; Winder, Alison; Vargervik, Karin; Haggstrom, Anita; Bamshad, Michael

    2005-10-01

    We report on a new patient with clinical findings consistent with acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome. The child had sparse hair, extensive freckling, lacrimal duct stenosis, oligodontia, dystrophic nails, reduced sweating, and bilateral athelia. Examination of his hands showed ulnar ray hypoplasia with bilateral fifth finger brachydactyly and camptodactyly. He also had surgical repair of an imperforate anus. Mutation analysis of TP63 showed a single nucleotide substitution, c.G518A, predicting a novel missense mutation, p.V114M in exon 4. This is the third mutation to be reported in TP63 in ADULT syndrome.

  11. Identification and characterization of two novel mutations that produce acute intermittent porphyria: A 3-base deletion (841-843delGGA) and a missense mutation (T35M).

    Science.gov (United States)

    De Siervi, A; Weiss Cádiz, D E; Parera, V E; del C Batlle, A M; Rossetti, M V

    2000-10-01

    A partial deficiency of Porphobilinogen deaminase (PBGD) is responsible for acute intermittent porphyria (AIP). AIP is inherited in an autosomal dominant fashion, and the prevalence in the Argentinean population is about 1:125,000. Here, two new mutations and two previously reported were found in the PBGD gene in 22 Argentinean AIP patients corresponding to 8 different families. To screen for AIP mutations in symptomatic patients, genomic DNA isolated was amplified in 6 PCR reactions, then all coding exons and flanking intronic regions were sequenced. The novel mutations are 841-843delGGA in exon 14, which results in the loss of glycine-281 (G281del), and one 104C>T point mutation in the exon 4 (T35M). To further characterize both novel mutations, the pKK-PBGD construct for the mutant alleles were expressed in E. coli, the enzymatic activity of the recombinant proteins were 1% and 4% of the mean level expressed by the normal allele for 841-843delGGA and T35M, respectively. Hum Mutat 16:373, 2000. Copyright 2000 Wiley-Liss, Inc.

  12. Oral and craniofacial manifestations and two novel missense mutations of the NTRK1 gene identified in the patient with congenital insensitivity to pain with anhidrosis.

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    Li Gao

    Full Text Available Congenital insensitivity to pain with anhidrosis (CIPA is a rare inherited disorder of the peripheral nervous system resulting from mutations in neurotrophic tyrosine kinase receptor 1 gene (NTRK1, which encodes the high-affinity nerve growth factor receptor TRKA. Here, we investigated the oral and craniofacial manifestations of a Chinese patient affected by autosomal-recessive CIPA and identified compound heterozygosity in the NTRK1 gene. The affected boy has multisystemic disorder with lack of reaction to pain stimuli accompanied by self-mutilation behavior, the inability to sweat leading to defective thermoregulation, and mental retardation. Oral and craniofacial manifestations included a large number of missing teeth, nasal malformation, submucous cleft palate, severe soft tissue injuries, dental caries and malocclusion. Histopathological evaluation of the skin sample revealed severe peripheral nerve fiber loss as well as mild loss and absent innervation of sweat glands. Ultrastructural and morphometric studies of a shed tooth revealed dental abnormalities, including hypomineralization, dentin hypoplasia, cementogenesis defects and a dysplastic periodontal ligament. Genetic analysis revealed a compound heterozygosity--c.1561T>C and c.2057G>A in the NTRK1 gene. This report extends the spectrum of NTRK1 mutations observed in patients diagnosed with CIPA and provides additional insight for clinical and molecular diagnosis.

  13. Oral and craniofacial manifestations and two novel missense mutations of the NTRK1 gene identified in the patient with congenital insensitivity to pain with anhidrosis.

    Science.gov (United States)

    Gao, Li; Guo, Hao; Ye, Nan; Bai, Yudi; Liu, Xin; Yu, Ping; Xue, Yang; Ma, Shufang; Wei, Kewen; Jin, Yan; Wen, Lingying; Xuan, Kun

    2013-01-01

    Congenital insensitivity to pain with anhidrosis (CIPA) is a rare inherited disorder of the peripheral nervous system resulting from mutations in neurotrophic tyrosine kinase receptor 1 gene (NTRK1), which encodes the high-affinity nerve growth factor receptor TRKA. Here, we investigated the oral and craniofacial manifestations of a Chinese patient affected by autosomal-recessive CIPA and identified compound heterozygosity in the NTRK1 gene. The affected boy has multisystemic disorder with lack of reaction to pain stimuli accompanied by self-mutilation behavior, the inability to sweat leading to defective thermoregulation, and mental retardation. Oral and craniofacial manifestations included a large number of missing teeth, nasal malformation, submucous cleft palate, severe soft tissue injuries, dental caries and malocclusion. Histopathological evaluation of the skin sample revealed severe peripheral nerve fiber loss as well as mild loss and absent innervation of sweat glands. Ultrastructural and morphometric studies of a shed tooth revealed dental abnormalities, including hypomineralization, dentin hypoplasia, cementogenesis defects and a dysplastic periodontal ligament. Genetic analysis revealed a compound heterozygosity--c.1561T>C and c.2057G>A in the NTRK1 gene. This report extends the spectrum of NTRK1 mutations observed in patients diagnosed with CIPA and provides additional insight for clinical and molecular diagnosis.

  14. Three unreported glucokinase (GCK) missense mutations detected in the screening of thirty-two Brazilian kindreds for GCK and HNF1A-MODY.

    Science.gov (United States)

    Weinert, Letícia S; Silveiro, Sandra P; Giuffrida, Fernando M A; Cunha, Vivian T; Bulcão, Caroline; Calliari, Luis Eduardo; Della Manna, Thais; Kunii, Ilda S; Dotto, Renata P; Dias-da-Silva, Magnus R; Reis, André F

    2014-11-01

    Thirty-two Brazilian families with MODY phenotype were screened for GCK and HNF1A mutations. GCK mutations were found in 8 families, all patients with mild asymptomatic hyperglycaemia; 3 of them are novel: p.Asp365Asn, p.Gly81Asp and p.Val253Leu. Previously described mutations in HNF1A were found in 2 families.

  15. A Missense Mutation in the LIM2 Gene Is Associated with Autosomal Recessive Presenile Cataract in an Inbred Iraqi Jewish Family

    Science.gov (United States)

    Pras, Eran; Levy-Nissenbaum, Etgar; Bakhan, Tangiz; Lahat, Hadas; Assia, Ehud; Geffen-Carmi, Noa; Frydman, Moshe; Goldman, Boleslaw; Pras, Elon

    2002-01-01

    In an inbred Iraqi Jewish family, we have studied three siblings with presenile cataract first noticed between the ages of 20 and 51 years and segregating in an autosomal recessive mode. Using microsatellite repeat markers in close proximity to 25 genes and loci previously associated with congenital cataracts in humans and mice, we identified five markers on chromosome 19q that cosegregated with the disease. Sequencing of LIM2, one of two candidate genes in this region, revealed a homozygous T→G change resulting in a phenylalanine-to-valine substitution at position 105 of the protein. To our knowledge, this constitutes the first report, in humans, of cataract formation associated with a mutation in LIM2. Studies of late-onset single-gene cataracts may provide insight into the pathogenesis of the more common age-related cataracts. PMID:11917274

  16. Case report: a novel KERA mutation associated with cornea plana and its predicted effect on protein function

    DEFF Research Database (Denmark)

    Roos, Laura; Bertelsen, Birgitte; Harris, Pernille;

    2015-01-01

    Background: Cornea plana (CNA) is a hereditary congenital abnormality of the cornea characterized by reduced corneal curvature, extreme hypermetropia, corneal clouding and hazy corneal limbus. The recessive form, CNA2, is associated with homozygous or compound heterozygous mutations of the kerato......Background: Cornea plana (CNA) is a hereditary congenital abnormality of the cornea characterized by reduced corneal curvature, extreme hypermetropia, corneal clouding and hazy corneal limbus. The recessive form, CNA2, is associated with homozygous or compound heterozygous mutations...... of the keratocan gene (KERA) on chromosome 12q22. To date, only nine different disease-associated KERA mutations, including four missense mutations, have been described. Case presentation: In this report, we present clinical data from a Turkish family with autosomal recessive cornea plana. In some of the affected...... individuals, hypotrichosis was found. KERA was screened for mutations using Sanger sequencing. We detected a novel KERA variant, p.(Ile225Thr), that segregates with the disease in the homozygous form. The three-dimensional structure of keratocan protein was modelled, and we showed that this missense variation...

  17. Novel Mutations in the PC Gene in Patients with Type B Pyruvate Carboxylase Deficiency

    DEFF Research Database (Denmark)

    Ostergaard, Elsebet; Duno, Morten; Møller, Lisbeth Birk

    2013-01-01

    We have investigated seven patients with the type B form of pyruvate carboxylase (PC) deficiency. Mutation analysis revealed eight mutations, all novel. In a patient with exon skipping on cDNA analysis, we identified a homozygous mutation located in a potential branch point sequence, the first...... possible branch point mutation in PC. Two patients were homozygous for missense mutations (with normal protein amounts on western blot analysis), and two patients were homozygous for nonsense mutations. In addition, a duplication of one base pair was found in a patient who also harboured a splice site...... mutation. Another splice site mutation led to the activation of a cryptic splice site, shown by cDNA analysis.All patients reported until now with at least one missense mutation have had the milder type A form of PC deficiency. We thus report for the first time two patients with homozygous missense...

  18. Exome sequencing identifies de novo gain of function missense mutation in KCND2 in identical twins with autism and seizures that slows potassium channel inactivation.

    Science.gov (United States)

    Lee, Hane; Lin, Meng-chin A; Kornblum, Harley I; Papazian, Diane M; Nelson, Stanley F

    2014-07-01

    Numerous studies and case reports show comorbidity of autism and epilepsy, suggesting some common molecular underpinnings of the two phenotypes. However, the relationship between the two, on the molecular level, remains unclear. Here, whole exome sequencing was performed on a family with identical twins affected with autism and severe, intractable seizures. A de novo variant was identified in the KCND2 gene, which encodes the Kv4.2 potassium channel. Kv4.2 is a major pore-forming subunit in somatodendritic subthreshold A-type potassium current (ISA) channels. The de novo mutation p.Val404Met is novel and occurs at a highly conserved residue within the C-terminal end of the transmembrane helix S6 region of the ion permeation pathway. Functional analysis revealed the likely pathogenicity of the variant in that the p.Val404Met mutant construct showed significantly slowed inactivation, either by itself or after equimolar coexpression with the wild-type Kv4.2 channel construct consistent with a dominant effect. Further, the effect of the mutation on closed-state inactivation was evident in the presence of auxiliary subunits that associate with Kv4 subunits to form ISA channels in vivo. Discovery of a functionally relevant novel de novo variant, coupled with physiological evidence that the mutant protein disrupts potassium current inactivation, strongly supports KCND2 as the causal gene for epilepsy in this family. Interaction of KCND2 with other genes implicated in autism and the role of KCND2 in synaptic plasticity provide suggestive evidence of an etiological role in autism.

  19. GRIN3B missense mutation as an inherited risk factor for schizophrenia: whole-exome sequencing in a family with a familiar history of psychotic disorders.

    Science.gov (United States)

    Hornig, Tobias; Grüning, Björn; Kundu, Kousik; Houwaart, Torsten; Backofen, Rolf; Biber, Knut; Normann, Claus

    2017-01-30

    Glutamate is the most important excitatory neurotransmitter in the brain. The N-methyl-D-aspartate (NMDA) receptor is a glutamate-gated ionotropic cation channel that is composed of several subunits and modulated by a glycine binding site. Many forms of synaptic plasticity depend on the influx of calcium ions through NMDA receptors, and NMDA receptor dysfunction has been linked to a number of neuropsychiatric disorders, including schizophrenia. Whole-exome sequencing was performed in a family with a strong history of psychotic disorders over three generations. We used an iterative strategy to obtain condense and meaningful variants. In this highly affected family, we found a frameshift mutation (rs10666583) in the GRIN3B gene, which codes for the GluN3B subunit of the NMDA receptor in all family members with a psychotic disorder, but not in the healthy relatives. Matsuno et al., also reported this null variant as a risk factor for schizophrenia in 2015. In a broader sample of 22 patients with psychosis, the allele frequency of the rs10666583 mutation variant was increased compared to those of healthy population samples and unaffected relatives. Compared to the 1000 Genomes Project population, we found a significant increase of this variant with a large effect size among patients. The amino acid shift degrades the S1/S2 glycine binding domain of the dominant modulatory GluN3B subunit of the NMDA receptor, which subsequently affects the permeability of the channel pore to calcium ions. A decreased glycine affinity for the GluN3B subunit might cause impaired functional capability of the NMDA receptor and could be an important risk factor for the pathogenesis of psychotic disorders.

  20. A missense mutation P136L in the arylsulfatase A gene causes instability and loss of activity of the mutant enzyme.

    Science.gov (United States)

    Kafert, S; Heinisch, U; Zlotogora, J; Gieselmann, V

    1995-02-01

    Metachromatic leukodystrophy is a lysosomal storage disease caused by deficiency of arylsulfatase A. Sequencing of the arylsulfatase A genes of an Ashkenazi Jewish patient suffering from the severe late infantile form of the disease revealed a point mutation in exon 2 causing proline 136 to be substituted by leucine. The patient was homozygous for this mutation. Studies on Ltk- cells stably expressing the mutant enzyme show that the mutation causes complete loss of enzyme activity and rapid degradation in an early biosynthetic compartment.

  1. Novel ATRX gene damaging missense mutation c.6740A>C segregates with profound to severe intellectual deficiency without alpha thalassaemia

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    Habib Bouazzi

    2016-01-01

    Interpretation & conclusions: The novel mutation c.6740A>C was identified within the ATRX gene helicase domain and confirmed by Sanger sequencing in the three affected males as well as in the mother and her two daughters. This mutation was predicted to be damaging and deleterious. The novel mutation segregated with the phenotype without alpha-thalassaemia and with non-skewed X chromosome.

  2. An overlapping phenotype of Osteogenesis imperfecta and Ehlers-Danlos syndrome due to a heterozygous mutation in COL1A1 and biallelic missense variants in TNXB identified by whole exome sequencing.

    Science.gov (United States)

    Mackenroth, Luisa; Fischer-Zirnsak, Björn; Egerer, Johannes; Hecht, Jochen; Kallinich, Tilmann; Stenzel, Werner; Spors, Birgit; von Moers, Arpad; Mundlos, Stefan; Kornak, Uwe; Gerhold, Kerstin; Horn, Denise

    2016-04-01

    Osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS) are variable genetic disorders that overlap in different ways [Cole 1993; Grahame 1999]. Here, we describe a boy presenting with severe muscular hypotonia, multiple fractures, and joint hyperflexibility, features that are compatible with mild OI and hypermobility type EDS, respectively. By whole exome sequencing, we identified both a COL1A1 mutation (c.4006-1G > A) inherited from the patient's mildly affected mother and biallelic missense variants in TNXB (p.Val1213Ile, p.Gly2592Ser). Analysis of cDNA showed that the COL1A1 splice site mutation led to intron retention causing a frameshift (p.Phe1336Valfs*72). Type 1 collagen secretion by the patient's skin fibroblasts was reduced. Immunostaining of a muscle biopsy obtained from the patient revealed a clear reduction of tenascin-X in the extracellular matrix compared to a healthy control. These findings imply that the combination of the COL1A1 mutation with the TNXB variants might cause the patient's unique phenotype.

  3. The Clinical Spectrum of Missense Mutations of the First Aspartic Acid of cbEGF-like Domains in Fibrillin-1 Including a Recessive Family

    NARCIS (Netherlands)

    Hilhorst-Hofstee, Yvonne; Rijlaarsdam, Marry E. B.; Scholte, Arthur J. H. A.; Swart-van den Berg, Marietta; Versteegh, Michel I. M.; van der Schoot-van Velzen, Iris; Schaebitz, Hans-Joachim; Bijlsma, Emilia K.; Baars, Marieke J.; Kerstjens-Frederikse, Wilhelmina S.; Giltay, Jacques C.; Hamel, Ben C.; Breuning, Martijn H.; Pals, Gerard

    2010-01-01

    Marfan syndrome (MFS) is a dominant disorder with a recognizable phenotype. In most patients with the classical phenotype mutations are found in the fibrillin-1 gene (FBN1) on chromosome 15q21. It is thought that most mutations act in a dominant negative way or through haploinsufficiency. In 9 index

  4. Identification of p.A684V missense mutation in the WFS1 gene as a frequent cause of autosomal dominant optic atrophy and hearing impairment

    DEFF Research Database (Denmark)

    Rendtorff, Nanna D; Lodahl, Marianne; Boulahbel, Houda

    2011-01-01

    Optic atrophy (OA) and sensorineural hearing loss (SNHL) are key abnormalities in several syndromes, including the recessively inherited Wolfram syndrome, caused by mutations in WFS1. In contrast, the association of autosomal dominant OA and SNHL without other phenotypic abnormalities is rare......, and almost exclusively attributed to mutations in the Optic Atrophy-1 gene (OPA1), most commonly the p.R445H mutation. We present eight probands and their families from the US, Sweden, and UK with OA and SNHL, whom we analyzed for mutations in OPA1 and WFS1. Among these families, we found three heterozygous...... DNA deletions were detected in muscle from one p.A684V patient analyzed. Finally, wolframin p.A684V mutant ectopically expressed in HEK cells showed reduced protein levels compared to wild-type wolframin, strongly indicating that the mutation is disease-causing. Our data support OA and SNHL...

  5. Detection and functional characterization of the novel missense mutation Y254D in type II 3{beta}-hydroxysteroid dehydrogenase (3{beta}HSD) gene of a female patient with nonsalt-losing 3{beta}HSD deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, R.; Rheaume, E.; Laflamme, N.; Labrie, F.; Simard, J. [Laval Univ., Quebec (Canada); Rosenfield, R.L. [Univ. of Chicago, IL (United States)

    1994-03-01

    Three {beta}-hydroxysteroid dehydrogenase/{Delta}{sup 5}-{Delta}{sup 4}-isomerase (3{beta}HSD) deficiency is a form of congenital adrenal hyperplasia characterized by severe impairment of steroid biosynthesis in the adrenals and gonads. To better understand the molecular basis of the phenotypic heterogeneity found in 3{beta}HSD deficiency, the authors analyzed the structure of type I and II 3{beta}HSD genes in a female patient with nonsalt-losing 3{beta}HSD deficiency diagnosed at puberty. They directly sequenced DNA fragments generated by polymerase chain reaction amplification of the four exons, the exon-intron boundaries, and the 5{prime}-flanking regions of each gene. No mutation was detected in the type I 3{beta}HSD gene, which is the predominant species expressed in the placenta and peripheral tissues. They detected a novel missense mutation, Y254D, in one allele of the patient`s type II 3{beta}HSD gene, which is the almost exclusive type expressed in the adrenals and gonads. The influence of the Y254D mutation on enzymatic activity was assessed by analyzing the recombinant mutant enzyme generated by site-directed mutagenesis after its transient expression in COS-1 monkey kidney cells. Recombinant mutant type II 3{beta}HSD enzyme carrying the Y254D substitution exhibits no detectable activity with C{sub 21} {Delta}{sup 5}-steroid pregnenolone or C{sub 19} {Delta}{sup 5}-steroid hydroepiandrosterone used as substrate. The absence of restriction fragment length polymorphism by Southern blot analysis and the finding that all of the amplified DNA fragments possess the expected length suggest the absence of deletions, duplications, or rearrangements in the other allele. A putative second mutation could be located farther than 1427 basepairs upstream of the initiation codon, thus potentially affecting the normal expression of this gene or within intronic regions, generating an alternative aberrant splicing site. 43 refs., 5 figs., 1 tab.

  6. Neonatal onset autosomal dominant polycystic kidney disease (ADPKD) in a patient homozygous for a PKD2 missense mutation due to uniparental disomy.

    NARCIS (Netherlands)

    Losekoot, M.; Ruivenkamp, C.A.; Tholens, A.P.; Grimbergen, J.E.; Vijfhuizen, L.; Vermeer, S.; Dijkman, H.B.P.M.; Cornelissen, E.A.M.; Bongers, M.H.F.; Peters, D.J.

    2012-01-01

    Autosomal dominant polycystic kidney disease (ADPKD), due to a heterozygous mutation in PKD1 or PKD2, is usually an adult onset disease. Renal cystic disease is generally milder in PKD2 patients than in PKD1 patients. Recently, several PKD1 patients with a severe renal cystic phenotype due to a seco

  7. Novel missense mutation in the L1 gene in a child with corpus callosum agenesis, retardation, adducted thumbs, spastic paraparesis, and hydrocephalus

    NARCIS (Netherlands)

    Sztriha, L; Frossard, P; Hofstra, RMW; Verlind, E; Nork, M

    2000-01-01

    Corpus callosum agenesis, retardation, adducted thumbs, spastic paraparesis, and hydrocephalus (CRASH syndrome) is an X-linked recessive disorder caused by mutations in the neuronal cell adhesion molecule L1 (L1CAM) gene. L1 plays a key role in axon outgrowth and pathfinding during the development o

  8. Identification of the PLA2G6 c.1579G>A Missense Mutation in Papillon Dog Neuroaxonal Dystrophy Using Whole Exome Sequencing Analysis

    Science.gov (United States)

    Tsuboi, Masaya; Watanabe, Manabu; Nibe, Kazumi; Yoshimi, Natsuko; Kato, Akihisa; Sakaguchi, Masahiro; Yamato, Osamu; Tanaka, Miyuu; Kuwamura, Mitsuru; Kushida, Kazuya; Harada, Tomoyuki; Chambers, James Kenn; Sugano, Sumio; Uchida, Kazuyuki; Nakayama, Hiroyuki

    2017-01-01

    Whole exome sequencing (WES) has become a common tool for identifying genetic causes of human inherited disorders, and it has also recently been applied to canine genome research. We conducted WES analysis of neuroaxonal dystrophy (NAD), a neurodegenerative disease that sporadically occurs worldwide in Papillon dogs. The disease is considered an autosomal recessive monogenic disease, which is histopathologically characterized by severe axonal swelling, known as “spheroids,” throughout the nervous system. By sequencing all eleven DNA samples from one NAD-affected Papillon dog and her parents, two unrelated NAD-affected Papillon dogs, and six unaffected control Papillon dogs, we identified 10 candidate mutations. Among them, three candidates were determined to be “deleterious” by in silico pathogenesis evaluation. By subsequent massive screening by TaqMan genotyping analysis, only the PLA2G6 c.1579G>A mutation had an association with the presence or absence of the disease, suggesting that it may be a causal mutation of canine NAD. As a human homologue of this gene is a causative gene for infantile neuroaxonal dystrophy, this canine phenotype may serve as a good animal model for human disease. The results of this study also indicate that WES analysis is a powerful tool for exploring canine hereditary diseases, especially in rare monogenic hereditary diseases. PMID:28107443

  9. Cortical synaptic transmission in CaV2.1 knockin mice with the S218L missense mutation which causes a severe familial hemiplegic migraine syndrome in humans.

    Directory of Open Access Journals (Sweden)

    Dania eVecchia

    2015-02-01

    Full Text Available Familial hemiplegic migraine type 1 (FHM1 is caused by gain-of-function mutations in CaV2.1 (P/Q-type Ca2+ channels. Knockin (KI mice carrying the FHM1 R192Q missense mutation show enhanced cortical excitatory synaptic transmission at pyramidal cell synapses but unaltered cortical inhibitory neurotransmission at fast-spiking interneuron synapses. Enhanced cortical glutamate release was shown to cause the facilitation of cortical spreading depression (CSD in R192Q KI mice. It, however, remains unknown how other FHM1 mutations affect cortical synaptic transmission. Here, we studied neurotransmission in cortical neurons in microculture from KI mice carrying the S218L mutation, which causes a severe FHM syndrome in humans and an allele-dosage dependent facilitation of experimental CSD in KI mice, which is larger than that caused by the R192Q mutation. We show gain-of-function of excitatory neurotransmission, due to increased action-potential evoked Ca2+ influx and increased probability of glutamate release at pyramidal cell synapses, but unaltered inhibitory neurotransmission at multipolar interneuron synapses in S218L KI mice. In contrast with the larger gain-of-function of neuronal CaV2.1 current in homozygous than heterozygous S218L KI mice, the gain-of-function of evoked glutamate release, the paired-pulse ratio and the Ca2+ dependence of the EPSC were all similar in homozygous and heterozygous S218L KI mice, suggesting compensatory changes in the homozygous mice. Furthermore, we reveal a unique feature of S218L KI cortical synapses which is the presence of a fraction of mutant CaV2.1 channels being open at resting potential. Our data suggest that, while the gain-of-function of evoked glutamate release may explain the facilitation of CSD in heterozygous S218L KI mice, the further facilitation of CSD in homozygous S218L KI mice is due to other CaV2.1-dependent mechanisms, that likely include Ca2+ influx at voltages sub-threshold for action

  10. A missense mutant myostatin causes hyperplasia without hypertrophy in the mouse muscle.

    Science.gov (United States)

    Nishi, Masumi; Yasue, Akihiro; Nishimatu, Shinichirou; Nohno, Tsutomu; Yamaoka, Takashi; Itakura, Mitsuo; Moriyama, Keiji; Ohuchi, Hideyo; Noji, Sumihare

    2002-04-26

    Myostatin, which is a member of the TGF-beta superfamily, is a negative regulator of skeletal muscle formation. Double-muscled Piedmontese cattle have a C313Y mutation in myostatin and show increased skeletal muscle mass which resulted from an increase of myofiber number (hyperplasia) without that of myofiber size (hypertrophy). To examine whether this mutation in myostatin gene affects muscle development in a dominant negative manner, we generated transgenic mice overexpressing the mutated gene. The transgenic mice exhibited dramatic increases in the skeletal muscle mass resulting from hyperplasia without hypertrophy. In contrast, it has been reported that a myostatin mutated at its cleavage site produces hypertrophy without hyperplasia in the muscle. Thus, these results suggest that (1) the myostatin containing the missense mutation exhibits a dominant negative activity and that (2) there are two types in the dominant negative form of myostatin, causing either hypertrophy or hyperplasia.

  11. Systemic vascular phenotypes of Loeys-Dietz syndrome in a child carrying a de novo R381P mutation in TGFBR2: a case report

    OpenAIRE

    Uike, Kiyoshi; Matsushita, Yuki; Sakai, Yasunari; Togao, Osamu; Nagao, Michinobu; Ishizaki, Yoshito; Nagata, Hazumu; Yamamura, Kenichiro; Torisu, Hiroyuki; Hara, Toshiro

    2013-01-01

    Background Loeys–Dietz syndrome, also known as Marfan syndrome type II, is a rare connective tissue disorder caused by dominant mutations in transforming growth factor-beta receptors (TGFBR1 and 2). Case presentation We report a 7-year-old Japanese boy with Loeys–Dietz syndrome who carried a novel, de novo missense mutation in TGFBR2 (c.1142g > c, R381P). He showed dysmorphic faces and skeletal malformations that were typical in previous cases with Loeys-Dietz syndrome. The cardiac studies di...

  12. Systemic vascular phenotypes of Loeys-Dietz syndrome in a child carrying a de novo R381P mutation in TGFBR2: a case report

    OpenAIRE

    Uike, Kiyoshi; MATSUSHITA, YUKI; Sakai, Yasunari; Togao, Osamu; Nagao, Michinobu; Ishizaki, Yoshito; Nagata, Hazumu; Yamamura, Kenichiro; Torisu, Hiroyuki; Hara, Toshiro

    2013-01-01

    Background Loeys–Dietz syndrome, also known as Marfan syndrome type II, is a rare connective tissue disorder caused by dominant mutations in transforming growth factor-beta receptors (TGFBR1 and 2). Case presentation We report a 7-year-old Japanese boy with Loeys–Dietz syndrome who carried a novel, de novo missense mutation in TGFBR2 (c.1142g > c, R381P). He showed dysmorphic faces and skeletal malformations that were typical in previous cases with Loeys-Dietz syndrome. The cardiac studies di...

  13. Missense mutation of FUT1 and deletion of FUT2 are responsible for Indian Bombay phenotype of ABO blood group system.

    Science.gov (United States)

    Koda, Y; Soejima, M; Johnson, P H; Smart, E; Kimura, H

    1997-09-08

    The Bombay phenotype fails to express the ABH antigens of ABO blood group system on red blood cells and in secretions because of a lack in activities of the H gene (FUT1)- and Secretor gene (FUT2)-encoded alpha (1,2)fucosyltransferases. In this study, we have examined the FUT1 and the FUT2 from three unrelated Indian individuals with the Bombay phenotype. These three individuals were found to be homozygous for a T725G mutation in the coding region of the FUT1, which inactivated the enzyme activity. In addition, we did not detect any hybridized band corresponding to the FUT2 by Southern blot analysis using the catalytic domain of the FUT2 as a probe, indicating that the three individuals were homozygous for a gene deletion in the FUT2. These results suggest that the T725G mutation of FUT1 and the gene deletion of FUT2 are responsible for the classical Indian Bombay phenotype.

  14. Missense mutations in pyruvate kinase M2 promote cancer metabolism, oxidative endurance, anchorage independence, and tumor growth in a dominant negative manner.

    Science.gov (United States)

    Iqbal, Mohd Askandar; Siddiqui, Farid Ahmad; Chaman, Noor; Gupta, Vibhor; Kumar, Bhupender; Gopinath, Prakasam; Bamezai, Rameshwar N K

    2014-03-21

    The present study was designed to examine the functional relevance of two heterozygous mutations (H391Y and K422R), observed earlier by us in the Bloom syndrome condition. Cells stably expressing exogenous wild-type or mutant PKM2 (K422R or H391Y) or co-expressing both wild type and mutant (PKM2-K422R or PKM2-H391Y) were assessed for cancer metabolism and tumorigenic potential. Interestingly, cells co-expressing PKM2 and mutant (K422R or H391Y) showed significantly aggressive cancer metabolism as compared with cells expressing either wild-type or mutant PKM2 independently. A similar trend was observed for oxidative endurance, tumorigenic potential, cellular proliferation, and tumor growth. These observations signify the dominant negative nature of mutations. Remarkably, PKM2-H391Y co-expressed cells showed a maximal effect on all the studied parameters. Such a dominant negative impaired function of PKM2 in tumor development is not known; this study demonstrates for the first time the possible predisposition of Bloom syndrome patients with impaired PKM2 activity to cancer and the importance of studying genetic variations in PKM2 in the future to understand their relevance in cancer in general.

  15. Using diverse U.S. beef cattle genomes to identify missense mutations in EPAS1, a gene associated with high-altitude pulmonary hypertension [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Michael P. Heaton

    2016-08-01

    Full Text Available The availability of whole genome sequence (WGS data has made it possible to discover protein variants in silico. However, existing bovine WGS databases do not show data in a form conducive to protein variant analysis, and tend to under represent the breadth of genetic diversity in U.S. beef cattle. Thus, our first aim was to use 96 beef sires, sharing minimal pedigree relationships, to create a searchable and publicly viewable set of mapped genomes relevant for 19 popular breeds of U.S. cattle. Our second aim was to identify protein variants encoded by the bovine endothelial PAS domain-containing protein 1 gene (EPAS1, a gene associated with high-altitude pulmonary hypertension in Angus cattle. The identity and quality of genomic sequences were verified by comparing WGS genotypes to those derived from other methods. The average read depth, genotype scoring rate, and genotype accuracy exceeded 14, 99%, and 99%, respectively. The 96 genomes were used to discover four amino acid variants encoded by EPAS1 (E270Q, P362L, A671G, and L701F and confirm two variants previously associated with disease (A606T and G610S. The six EPAS1 missense mutations were verified with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry assays, and their frequencies were estimated in a separate collection of 1154 U.S. cattle representing 46 breeds. A rooted phylogenetic tree of eight polypeptide sequences provided a framework for evaluating the likely order of mutations and potential impact of EPAS1 alleles on the adaptive response to chronic hypoxia in U.S. cattle. This public, whole genome resource facilitates in silico identification of protein variants in diverse types of U.S. beef cattle, and provides a means of translating WGS data into a practical biological and evolutionary context for generating and testing hypotheses.

  16. Association of a missense mutation in the luteinizing hormone/choriogonadotropin receptor gene (LHCGR) with superovulation traits in Chinese Holstein heifers

    Science.gov (United States)

    2012-01-01

    Background Upon binding luteinizing hormone in the ovary, the luteinizing hormone/choriogonadotropin receptor (LHCGR) is necessary for follicular maturation and ovulation, as well as luteal function. We detected mutations in the LHCGR gene and evaluated their association with superovulation. Methods Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing, we examined polymorphisms in LHCGR and the genotypes associated with superovulation traits in 127 Chinese Holstein heifers. Results A G/T polymorphism (ss52050737) in exon 11 was significantly associated with the total number of ova and the number of transferable embryos. Conclusions LHCGR may be a new predictor for superovulation in Chinese Holstein heifers. PMID:23140330

  17. Missense Mutations in LRP5 Associated with High Bone Mass Protect the Mouse Skeleton from Disuse- and Ovariectomy-Induced Osteopenia

    Science.gov (United States)

    Niziolek, Paul J.; Bullock, Whitney; Warman, Matthew L.; Robling, Alexander G.

    2015-01-01

    The low density lipoprotein receptor-related protein-5 (LRP5), a co-receptor in the Wnt signaling pathway, modulates bone mass in humans and in mice. Lrp5 knock-out mice have severely impaired responsiveness to mechanical stimulation whereas Lrp5 gain-of-function knock-in and transgenic mice have enhanced responsiveness to mechanical stimulation. Those observations highlight the importance of Lrp5 protein in bone cell mechanotransduction. It is unclear if and how high bone mass-causing (HBM) point mutations in Lrp5 alter the bone-wasting effects of mechanical disuse. To address this issue we explored the skeletal effects of mechanical disuse using two models, tail suspension and Botulinum toxin-induced muscle paralysis, in two different Lrp5 HBM knock-in mouse models. A separate experiment employing estrogen withdrawal-induced bone loss by ovariectomy was also conducted as a control. Both disuse stimuli induced significant bone loss in WT mice, but Lrp5 A214V and G171V were partially or fully protected from the bone loss that normally results from disuse. Trabecular bone parameters among HBM mice were significantly affected by disuse in both models, but these data are consistent with DEXA data showing a failure to continue growing in HBM mice, rather than a loss of pre-existing bone. Ovariectomy in Lrp5 HBM mice resulted in similar protection from catabolism as was observed for the disuse experiments. In conclusion, the Lrp5 HBM alleles offer significant protection from the resorptive effects of disuse and from estrogen withdrawal, and consequently, present a potential mechanism to mimic with pharmaceutical intervention to protect against various bone-wasting stimuli. PMID:26554834

  18. Missense Mutations in LRP5 Associated with High Bone Mass Protect the Mouse Skeleton from Disuse- and Ovariectomy-Induced Osteopenia.

    Science.gov (United States)

    Niziolek, Paul J; Bullock, Whitney; Warman, Matthew L; Robling, Alexander G

    2015-01-01

    The low density lipoprotein receptor-related protein-5 (LRP5), a co-receptor in the Wnt signaling pathway, modulates bone mass in humans and in mice. Lrp5 knock-out mice have severely impaired responsiveness to mechanical stimulation whereas Lrp5 gain-of-function knock-in and transgenic mice have enhanced responsiveness to mechanical stimulation. Those observations highlight the importance of Lrp5 protein in bone cell mechanotransduction. It is unclear if and how high bone mass-causing (HBM) point mutations in Lrp5 alter the bone-wasting effects of mechanical disuse. To address this issue we explored the skeletal effects of mechanical disuse using two models, tail suspension and Botulinum toxin-induced muscle paralysis, in two different Lrp5 HBM knock-in mouse models. A separate experiment employing estrogen withdrawal-induced bone loss by ovariectomy was also conducted as a control. Both disuse stimuli induced significant bone loss in WT mice, but Lrp5 A214V and G171V were partially or fully protected from the bone loss that normally results from disuse. Trabecular bone parameters among HBM mice were significantly affected by disuse in both models, but these data are consistent with DEXA data showing a failure to continue growing in HBM mice, rather than a loss of pre-existing bone. Ovariectomy in Lrp5 HBM mice resulted in similar protection from catabolism as was observed for the disuse experiments. In conclusion, the Lrp5 HBM alleles offer significant protection from the resorptive effects of disuse and from estrogen withdrawal, and consequently, present a potential mechanism to mimic with pharmaceutical intervention to protect against various bone-wasting stimuli.

  19. Novel CFTR missense mutations in Brazilian patients with congenital absence of vas deferens: counseling issues Mutações novas no gene CFTR de pacientes brasileiros portadores de agenesia dos vasos deferentes: dificuldades no aconselhamento

    Directory of Open Access Journals (Sweden)

    Patricia de Campos Pieri

    2007-01-01

    Full Text Available PURPOSE: Screening for mutations in the entire Cystic Fibrosis gene (CFTR of Brazilian infertile men with congenital absence of vas deferens, in order to prevent transmission of CFTR mutations to offspring with the use of assisted reproductive technologies. METHOD: Specific polymerase chain reaction (PCR primers were designed to each of the 27 exons and splicing sites of interest followed by single strand conformational polymorphism and Heteroduplex Analysis (SSCP-HA in precast 12.5% polyacrylamide gels at 7ºC and 20ºC. Fragments with abnormal SSCP migration pattern were sequenced. RESULTS: Two novel missense mutations (S753R and G149W were found in three patients (two brothers together with the IVS8-5T allele in hetrozygosis. CONCLUSION: The available screenings for CF mutations do not include the atypical mutations associated to absence of vas deferens and thus, when these tests fail to find mutations, there is still a genetic risk of affected children with the help of assisted reproduction. We recommend the screening of the whole CFTR gene for these infertile couples, as part of the work-up before assisted reproduction.OBJETIVO: Pesquisar mutações em toda a extensão do gene que causa a Fibrose Cística (CFTR de homens brasileiros inférteis por agenesia congênita dos vasos deferentes, com a finalidade de prevenir a transmissão de mutações em CFTR à prole com o uso das tecnologias de reprodução assistida. MÉTODOS: Foram desenhados oligonucleotídeos específicos para realização de reação de polimerização em cadeia (PCR para cada um dos 27 exons e sítios de processamento de interesse no gene CFTR. O PCR foi seguido pela técnica de SSCP-HA (polimorfismos de conformação no DNA de fita simples e na formação de heteroduplexes em géis pré-fabricados de poliacrilamida a 12,5% em duas temperaturas, 7ºC e 20ºC. Os fragmentos com padrão alterado na migração do SSCP foram submetidos a seqüenciamento automatizado

  20. Missense Variants in ATM in 26,101 Breast Cancer Cases and 29,842 Controls

    DEFF Research Database (Denmark)

    Fletcher, O.; Johnson, N.; Silva, Andreá Lema Da

    2010-01-01

    Background: Truncating mutations in ATM have been shown to increase the risk of breast cancer but the effect of missense variants remains contentious. Methods: We have genotyped five polymorphic (minor allele frequency, 0.9-2.6%) missense single nucleotide polymorphisms (SNP) in ATM (S49C, S707P,...

  1. GJB2 (Cx26) gene mutations in Chinese patients with congenital sensorineural deafness and a report of one novel mutation

    Institute of Scientific and Technical Information of China (English)

    肖自安; 谢鼎华

    2004-01-01

    Background Mutations in GJB2 gene are a major cause of autosomal recessive congenital hearing loss and the cause in some rare cases of the autosomal dominant form. The purpose of This study was to investigate the frequency and the features of GJB2 mutations in the Chinese patients with congenital sensorineural deafness. Methods Using PCR amplifying the entire coding region of GJB2 gene and direct DNA sequencing to analyze mutations in this gene among unrelated 69 cases with autosomal recessive congenital nonsyndromic deafness and 27 cases of dominant congenital deafness and 35 sporadic cases. We also detected mutations in GJB2 in 100 control subjects with normal hearing.Results 17.4% (12/69) of the probands in the autosomal recessive, 7.4% (2/27) of dominant families and 5.7% (2/35) of the sporadic congenital deafness patients had deafness-causing mutations in GJB2, respectively. Nine types of the mutations in GJB2 were detected in the recessive and sporadic group. They consisted of five types of polymorphism, and four types of deafness-causing mutation with homozygous 35delG in 1 sporadic (1/35), and 235delC frameshift mutation in 1 sporadic (homozygotes) and 10 recessive patients (2 heterozygotes and 8 homozygotes), and homozygous 442G→A missense mutation and homozygous 465T→A nonsense mutation in 1 different recessive proband, respectively. The 465T→A that related to recessive deafness was a novel mutation found by this study. The homozygous (10/69, 14.5%) and the heterozygous (2/69, 2.9%) GJB2 mutation in the recessive patients (12/69, 17.4%) and the homozygotes in the sporadic patient (2/35, 5.7%) all had congenital severe to profound sensorineural hearing loss. 511G→A missense mutation and 299-300delAT frameshift mutation were found in two autosomal dominant congenital deafness families (2/27, 7.4%). The total mutation frequency of GJB2 was 12.2% (16/131) in the Chinese patients with congenital sensorineural deafness and 235delC was the most common

  2. Compound heterozygosity for mutations in LMNA causes a progeria syndrome without prelamin A accumulation.

    NARCIS (Netherlands)

    Verstraeten, V.L.; Broers, J.L.; Steensel, M.A.M. van; Zinn-Justin, S.; Ramaekers, F.C.S.; Steijlen, P.M.; Kamps, M.; Kuijpers, H.J.; Merckx, D.; Smeets, H.J.M.; Hennekam, R.C.M.; Marcelis, C.L.M.; Wijngaard, A. van de

    2006-01-01

    LMNA-associated progeroid syndromes have been reported with both recessive and dominant inheritance. We report a 2-year-old boy with an apparently typical Hutchinson-Gilford progeria syndrome (HGPS) due to compound heterozygous missense mutations (p.T528M and p.M540T) in LMNA. Both mutations affect

  3. Compound heterozygosity for mutations in LMNA causes a progeria syndrome without prelamin A accumulation.

    NARCIS (Netherlands)

    Verstraeten, V.L.; Broers, J.L.; Steensel, M.A.M. van; Zinn-Justin, S.; Ramaekers, F.C.S.; Steijlen, P.M.; Kamps, M.; Kuijpers, H.J.; Merckx, D.; Smeets, H.J.M.; Hennekam, R.C.M.; Marcelis, C.L.M.; Wijngaard, A. van de

    2006-01-01

    LMNA-associated progeroid syndromes have been reported with both recessive and dominant inheritance. We report a 2-year-old boy with an apparently typical Hutchinson-Gilford progeria syndrome (HGPS) due to compound heterozygous missense mutations (p.T528M and p.M540T) in LMNA. Both mutations affect

  4. In Silico Analysis of FMR1 Gene Missense SNPs.

    Science.gov (United States)

    Tekcan, Akin

    2016-06-01

    The FMR1 gene, a member of the fragile X-related gene family, is responsible for fragile X syndrome (FXS). Missense single-nucleotide polymorphisms (SNPs) are responsible for many complex diseases. The effect of FMR1 gene missense SNPs is unknown. The aim of this study, using in silico techniques, was to analyze all known missense mutations that can affect the functionality of the FMR1 gene, leading to mental retardation (MR) and FXS. Data on the human FMR1 gene were collected from the Ensembl database (release 81), National Centre for Biological Information dbSNP Short Genetic Variations database, 1000 Genomes Browser, and NHLBI Exome Sequencing Project Exome Variant Server. In silico analysis was then performed. One hundred-twenty different missense SNPs of the FMR1 gene were determined. Of these, 11.66 % of the FMR1 gene missense SNPs were in highly conserved domains, and 83.33 % were in domains with high variety. The results of the in silico prediction analysis showed that 31.66 % of the FMR1 gene SNPs were disease related and that 50 % of SNPs had a pathogenic effect. The results of the structural and functional analysis revealed that although the R138Q mutation did not seem to have a damaging effect on the protein, the G266E and I304N SNPs appeared to disturb the interaction between the domains and affect the function of the protein. This is the first study to analyze all missense SNPs of the FMR1 gene. The results indicate the applicability of a bioinformatics approach to FXS and other FMR1-related diseases. I think that the analysis of FMR1 gene missense SNPs using bioinformatics methods would help diagnosis of FXS and other FMR1-related diseases.

  5. Caveolin-3 Mutations in Rippling Muscle Disease

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2003-05-01

    Full Text Available Two unrelated patients with novel homozygous missense mutations (L86P and A92T in caveolin-3 gene (CAV3, presenting with a severe form of rippling muscle disease (RMD, are reported from the University of Bonn, and other centers in Germany.

  6. BAP1 missense mutation c.2054 A>T (p.E685V completely disrupts normal splicing through creation of a novel 5' splice site in a human mesothelioma cell line.

    Directory of Open Access Journals (Sweden)

    Arianne Morrison

    Full Text Available BAP1 is a tumor suppressor gene that is lost or deleted in diverse cancers, including uveal mela¬noma, malignant pleural mesothelioma (MPM, clear cell renal carcinoma, and cholangiocarcinoma. Recently, BAP1 germline mutations have been reported in families with combinations of these same cancers. A particular challenge for mutation screening is the classification of non-truncating BAP1 sequence variants because it is not known whether these subtle changes can affect the protein function sufficiently to predispose to cancer development. Here we report mRNA splicing analysis on a homozygous substitution mutation, BAP1 c. 2054 A&T (p.Glu685Val, identified in an MPM cell line derived from a mesothelioma patient. The mutation occurred at the 3rd nucleotide from the 3' end of exon 16. RT-PCR, cloning and subsequent sequencing revealed several aberrant splicing products not observed in the controls: 1 a 4 bp deletion at the end of exon 16 in all clones derived from the major splicing product. The BAP1 c. 2054 A&T mutation introduced a new 5' splice site (GU, which resulted in the deletion of 4 base pairs and presumably protein truncation; 2 a variety of alternative splicing products that led to retention of different introns: introns 14-16; introns 15-16; intron 14 and intron 16; 3 partial intron 14 and 15 retentions caused by activation of alternative 3' splice acceptor sites (AG in the introns. Taken together, we were unable to detect any correctly spliced mRNA transcripts in this cell line. These results suggest that aberrant splicing caused by this mutation is quite efficient as it completely abolishes normal splicing through creation of a novel 5' splice site and activation of cryptic splice sites. These data support the conclusion that BAP1 c.2054 A&T (p.E685V variant is a pathogenic mutation and contributes to MPM through disruption of normal splicing.

  7. Two novel RAD21 mutations in patients with mild Cornelia de Lange syndrome-like presentation and report of the first familial case.

    Science.gov (United States)

    Minor, Agata; Shinawi, Marwan; Hogue, Jacob S; Vineyard, Marisa; Hamlin, Damara R; Tan, Christopher; Donato, Kirsten; Wysinger, Latrice; Botes, Shaun; Das, Soma; Del Gaudio, Daniela

    2014-03-10

    Cornelia de Lange syndrome (CdLS) is a developmental disorder characterized by limb reduction defects, characteristic facial features and impaired cognitive development. Mutations in the NIPBL gene predominate; however, mutations in other cohesin complex genes have also been implicated, particularly in atypical and mild CdLS cases. Missense mutations and whole gene deletions in RAD21 have been identified in children with growth retardation, minor skeletal anomalies and facial features that overlap findings in individuals with CdLS. We report the first intragenic deletion and frameshift mutations identified in RAD21 in two patients presenting with atypical CdLS. One patient had an in-frame deletion of exon 13, while the second patient had a c.592_593dup frameshift mutation. The first patient presented with developmental delay, hypospadias, inguinal hernia and dysmorphic features while, the second patient presented with developmental delay, characteristic facial features, hirsutism, and hand and feet anomalies, with the first patient being milder than the second. The in-frame deletion mutation was found to be inherited from the mother who had a history of melanoma and other unspecified medical problems. This study expands the spectrum of RAD21 mutations and emphasizes the clinical utility of performing RAD21 mutation analysis in patients presenting with atypical forms of CdLS. Moreover, the variability of clinical presentation within families and low penetrance of mutations as well as the significance of performing molecular genetic testing in mildly affected patients are discussed. Published by Elsevier B.V.

  8. Update of the pompe disease mutation database with 60 novel GAA sequence variants and additional studies on the functional effect of 34 previously reported variants.

    Science.gov (United States)

    Kroos, Marian; Hoogeveen-Westerveld, Marianne; Michelakakis, Helen; Pomponio, Robert; Van der Ploeg, Ans; Halley, Dicky; Reuser, Arnold

    2012-08-01

    Pompe disease is an autosomal recessive lysosomal glycogen storage disorder, characterized by progressive muscle weakness. Deficiency of acid α-glucosidase (EC; 3.2.1.20/3) can be caused by numerous pathogenic variants in the GAA gene. The Pompe Disease Mutation Database at http://www.pompecenter.nl aims to list all variants and their effect. This update reports on 94 variants. We examined 35 novel and 34 known mutations by site-directed mutagenesis and transient expression in COS-7 cells or HEK293T cells. Each of these mutations was given a severity rating using a previously published system, based on the level of acid α-glucosidase activity in medium and transfected cells and on the quantity and quality of the different molecular mass species in the posttranslational modification and transport of acid α-glucosidase. This approach enabled to classify 55 missense mutations as pathogenic and 13 as likely nonpathogenic. Based on their nature and the use of in silico analysis (Alamut® software), 12 of the additional 25 novel mutations were predicted to be pathogenic including 4 splicing mutations, 6 mutations leading to frameshift, and 2 point mutations causing stop codons. Seven of the additional mutations were considered nonpathogenic (4 silent and 3 occurring in intron regions), and 6 are still under investigation.

  9. Homozygosity for a missense mutation in the 67 kDa isoform of glutamate decarboxylase in a family with autosomal recessive spastic cerebral palsy: parallels with Stiff-Person Syndrome and other movement disorders

    Directory of Open Access Journals (Sweden)

    Woods C Geoffrey

    2004-11-01

    Full Text Available Abstract Background Cerebral palsy (CP is an heterogeneous group of neurological disorders of movement and/or posture, with an estimated incidence of 1 in 1000 live births. Non-progressive forms of symmetrical, spastic CP have been identified, which show a Mendelian autosomal recessive pattern of inheritance. We recently described the mapping of a recessive spastic CP locus to a 5 cM chromosomal region located at 2q24-31.1, in rare consanguineous families. Methods Here we present data that refine this locus to a 0.5 cM region, flanked by the microsatellite markers D2S2345 and D2S326. The minimal region contains the candidate gene GAD1, which encodes a glutamate decarboxylase isoform (GAD67, involved in conversion of the amino acid and excitatory neurotransmitter glutamate to the inhibitory neurotransmitter γ-aminobutyric acid (GABA. Results A novel amino acid mis-sense mutation in GAD67 was detected, which segregated with CP in affected individuals. Conclusions This result is interesting because auto-antibodies to GAD67 and the more widely studied GAD65 homologue encoded by the GAD2 gene, are described in patients with Stiff-Person Syndrome (SPS, epilepsy, cerebellar ataxia and Batten disease. Further investigation seems merited of the possibility that variation in the GAD1 sequence, potentially affecting glutamate/GABA ratios, may underlie this form of spastic CP, given the presence of anti-GAD antibodies in SPS and the recognised excitotoxicity of glutamate in various contexts. Table 4 GAD1 single nucleotide substitutions detected on mutation analysis and occurring in sequences submitted to NCBI SNP database and in the literature. This is not a definitive list, but includes those described at the time of the mutational analysis. *Nucleotide positions were not provided by Maestrini et al. [47]. Source SNP position in mRNA, from the translational start site (bp Gene position of SNP(bp Amino acid change (ALappalainen et al. (2002 A(-478Del Exon

  10. Most of rare missense alleles in humans are deleterious:implications for evolution of complex disease and associationstudies

    Energy Technology Data Exchange (ETDEWEB)

    Kryukov, Gregory V.; Pennacchio, Len A.; Sunyaev, Shamil R.

    2006-10-24

    The accumulation of mildly deleterious missense mutations inindividual human genomes has been proposed to be a genetic basis forcomplex diseases. The plausibility of this hypothesis depends onquantitative estimates of the prevalence of mildly deleterious de novomutations and polymorphic variants in humans and on the intensity ofselective pressure against them. We combined analysis of mutationscausing human Mendelian diseases, human-chimpanzee divergence andsystematic data on human SNPs and found that about 20 percent of newmissense mutations in humans result in a loss of function, while about 27percent are effectively neutral. Thus, more than half of new missensemutations have mildly deleterious effects. These mutations give rise tomany low frequency deleterious allelic variants in the human populationas evident from a new dataset of 37 genes sequenced in over 1,500individual human chromosomes. Surprisingly, up to 70 percent of lowfrequency missense alleles are mildly deleterious and associated with aheterozygous fitness loss in the range 0.001-0.003. Thus, the low allelefrequency of an amino acid variant can by itself serve as a predictor ofits functional significance. Several recent studies have reported asignificant excess of rare missense variants in disease populationscompared to controls in candidate genes or pathways. These studies wouldbe unlikely to work if most rare variants were neutral or if rarevariants were not a significant contributor to the genetic component ofphenotypic inheritance. Our results provide a justification for thesetypes of candidate gene (pathway) association studies and imply thatmutation-selection balance may be a feasible mechanism for evolution ofsome common diseases.

  11. New SMARCA2 mutation in a patient with Nicolaides–Baraitser syndrome and myoclonic astatic epilepsy

    OpenAIRE

    S. Tang; Hughes, E.(Rutgers, The State University of New Jersey, Piscataway, USA); Lascelles, K.; Simpson, M A; Pal, D. K.; Marini, C.; Guerrini, R.; Neubauer, B; Korff, C. M.; D. Craiu; Pal, D.; Caglayan, H.; Helbig, I.; De Jonghe, P; Thomas, R.

    2017-01-01

    We report a de novo SMARCA2 missense mutation discovered on exome sequencing in a patient with myoclonic astatic epilepsy, leading to reassessment and identification of Nicolaides–Baraitser syndrome. This de novo SMARCA2 missense mutation c.3721C>G, p.Gln1241Glu is the only reported mutation on exon 26 outside the ATPase domain of SMARCA2 to be associated with Nicolaides–Baraitser syndrome and adds to chromatin remodeling as a pathway for epileptogenesis. © 2016 The Authors. American Journal ...

  12. KD4v: Comprehensible Knowledge Discovery System for Missense Variant.

    Science.gov (United States)

    Luu, Tien-Dao; Rusu, Alin; Walter, Vincent; Linard, Benjamin; Poidevin, Laetitia; Ripp, Raymond; Moulinier, Luc; Muller, Jean; Raffelsberger, Wolfgang; Wicker, Nicolas; Lecompte, Odile; Thompson, Julie D; Poch, Olivier; Nguyen, Hoan

    2012-07-01

    A major challenge in the post-genomic era is a better understanding of how human genetic alterations involved in disease affect the gene products. The KD4v (Comprehensible Knowledge Discovery System for Missense Variant) server allows to characterize and predict the phenotypic effects (deleterious/neutral) of missense variants. The server provides a set of rules learned by Induction Logic Programming (ILP) on a set of missense variants described by conservation, physico-chemical, functional and 3D structure predicates. These rules are interpretable by non-expert humans and are used to accurately predict the deleterious/neutral status of an unknown mutation. The web server is available at http://decrypthon.igbmc.fr/kd4v.

  13. Pyridoxine-responsive seizures as the first symptom of infantile hypophosphatasia caused by two novel missense mutations (c.677T>C, p.M226T; c.1112C>T, p.T371I) of the tissue-nonspecific alkaline phosphatase gene.

    Science.gov (United States)

    Baumgartner-Sigl, Sara; Haberlandt, Edda; Mumm, Steven; Scholl-Bürgi, Sabine; Sergi, Consolato; Ryan, Lawrence; Ericson, Karen L; Whyte, Michael P; Högler, Wolfgang

    2007-06-01

    Pyridoxine-responsive seizures (PRS) and the role of pyridoxine (PN, vitamin B(6)) in hypophosphatasia (HPP) are incompletely understood. Typically, PRS and HPP are rare, independent, metabolic disorders. In PRS, seizures resist standard anticonvulsants apart from PN, yet have a good prognosis. In HPP, inactivation of the tissue nonspecific isoenzyme of alkaline phosphatase (TNSALP) impairs skeletal mineralization and causes rickets in infants that can be fatal. Here, we report a 7-month-old girl, newly diagnosed with infantile HPP, who presented as a neonate with PRS but without bony abnormalities. Analysis of biogenic amines in cerebrospinal fluid (CSF) suggested brain pyridoxal 5'-phosphate (PLP) deficiency, although PLP in CSF was not decreased. She had normal cognitive milestones but failure to thrive and rickets. Nearly undetectable serum ALP activity, elevated plasma PLP and urinary phosphoethanolamine (PEA) and inorganic pyrophosphate (PPi) levels, hypercalcemia, hypercalciuria and nephrocalcinosis were consistent with infantile HPP. Only prednisolone reduced serum calcium levels. Despite improved growth and weight gain, she developed rib fractures and died from respiratory failure at age 9 months. Sequence analysis of the TNSALP gene revealed novel missense mutations in exon 7 (c.677T>C, p.M226T) and exon 10 (c.1112C>T, p.T371I). Our patient demonstrated that PRS in neonates may not necessarily be "idiopathic"; instead, such seizures can be caused by severe HPP that becomes clinically apparent later in infancy. The pathophysiology of PRS in HPP differs from the three other genetic defects known to cause PRS, but all may lead to brain PLP deficiency reducing seizure thresholds. All reported HPP patients with neonatal seizures died within 18 months of birth, suggesting that PRS is an indicator of HPP severity and lethal prognosis. We recommend that assessment of any neonate with PRS should include measurement of serum ALP activity.

  14. Novel Mutations in the Transcriptional Activator Domain of the Human TBX20 in Patients with Atrial Septal Defect

    Directory of Open Access Journals (Sweden)

    Irma Eloisa Monroy-Muñoz

    2015-01-01

    Full Text Available Background. The relevance of TBX20 gene in heart development has been demonstrated in many animal models, but there are few works that try to elucidate the effect of TBX20 mutations in human congenital heart diseases. In these studies, all missense mutations associated with atrial septal defect (ASD were found in the DNA-binding T-box domain, none in the transcriptional activator domain. Methods. We search for TBX20 mutations in a group of patients with ASD or ventricular septal defect (VSD using the High Resolution Melting (HRM method and DNA sequencing. Results. We report three missense mutations (Y309D, T370O, and M395R within the transcriptional activator domain of human TBX20 that were associated with ASD. Conclusions. This is the first association of TBX20 transcriptional activator domain missense mutations with ASD. These findings could have implications for diagnosis, genetic screening, and patient follow-up.

  15. Small FVIII gene rearrangements in 18 hemophilia A patients: five novel mutations.

    Science.gov (United States)

    Bicocchi, Maria Patrizia; Pasino, Mirella; Lanza, Tiziana; Bottini, Federico; Molinari, Angelo Claudio; Caprino, Daniela; Rosano, Camillo; Acquila, Maura

    2005-02-01

    Hemophilia A (HA) is a disorder caused by mutations of the FVIII gene, which is located on the tip of the long arm of the X chromosome. In a cohort of 18 unrelated Italian patients affected with HA of varying severity, we performed mutational screening of the gene by denaturing high-performance liquid chromatography (DHPLC) and direct sequencing of abnormal peaks. We identified five novel mutations and 9 previously reported DNA alterations. Two of the 9 previously reported alterations were each common to 3 unrelated patients. Six different mutations were characterized as missense alterations, while 8 were non-missense mutations. Among the new gene alterations, one created a stop codon, one consisted of an out-of frame deletion, and one was a splice-site mutation. The last two were missense alterations. In an attempt to better understand the causative effect of the mutations and the clinical variability of the patients, we investigated the consequences of each missense mutation and visualized the effect of the amino acid change on structural FVIII models.

  16. Vascular-type Ehlers-Danlos syndrome caused by a hitherto unknown genetic mutation: a case report

    Directory of Open Access Journals (Sweden)

    Kashizaki Fumihiro

    2013-02-01

    Full Text Available Abstract Introduction Vascular-type Ehlers-Danlos syndrome is an autosomal dominant disease that causes arterial spurting, intestinal perforation, uterine rupture and hemopneumothorax due to decreased production of type III collagen. The average age at death is 48 years old, and it is considered to be the most severe form of Ehlers-Danlos syndrome. We report the case of a 64-year-old Japanese woman and her 38-year-old daughter who were diagnosed with this disease. Case presentation A 64-year-old Japanese woman was referred to our hospital because of right anterior chest pain following cough and pharyngeal discomfort. Pleurisy was suspected due to the presence of right pleural effusion, so the next day she was referred to our department, where a detailed examination led to the diagnosis of hemothorax. The bleeding that caused the right hemothorax was difficult to control, so our patient was transferred to the Department of Thoracic Surgery for hemostasis control. Our patient’s personal history of uterine hemorrhage and skin ulcers, as well as the finding of skin fragility during surgery, were indicative of a weak connective tissue disease; therefore, after improvement of the hemothorax, a genetic analysis was performed. This revealed a heterozygous missense mutation in COL3A1, c.2411 G>T p.Gly804Val (exon 36. A detailed investigation conducted at a later date revealed that her daughter also had the same genetic mutation. This led to the diagnosis of vascular-type Ehlers-Danlos syndrome characterized by a new gene mutation. Conclusion We report a new genetic mutation associated with vascular-type Ehlers-Danlos syndrome. We present the clinical and imaging findings, and the disease and treatment course in this patient. We believe this information will be important in treating future cases of vascular-type Ehlers-Danlos syndrome in patients with this mutation.

  17. Phenylalanine hydroxylase gene mutations in the United States: Report from the maternal PKU collaborative study

    Energy Technology Data Exchange (ETDEWEB)

    Guldberg, P.; Henriksen, K.F.; Guettler, F. [John F. Kennedy Inst., Glostrup (Denmark)] [and others

    1996-07-01

    The major cause of hyperphenylalaninemia is mutations in the gene encoding phenylalanine hydroxylase (PAH). The known mutations have been identified primarily in European patients. The purpose of this study was to determine the spectrum of mutations responsible for PAH deficiency in the United States. One hundred forty-nine patients enrolled in the Maternal PKU Collaborative Study were subjects for clinical and molecular investigations. PAH gene mutations associated with phenylketonuria (PKU) or mild hyperphenylalaninemia (MHP) were identified on 279 of 294 independent mutant chromosomes, a diagnostic efficiency of 95%. The spectrum is composed of 71 different mutations, including 47 missense mutations, 11 splice mutations, 5 nonsense mutations, and 8 microdeletions. Sixteen previously unreported mutations were identified. Among the novel mutations, five were found in patients with MHP, and the remainder were found in patients with PKU. The most common mutations were R408W, IVS12nt1g{r_arrow}a, and Y414C, accounting for 18.7%, 7.8% and 5.4% of the mutant chromosomes, respectively. Thirteen mutations had relative frequencies of 1%-5%, and 55 mutations each had frequencies {le}1%. The mutational spectrum corresponded to that observed for the European ancestry of the U.S. population. To evaluate the extent of allelic variation at the PAH locus within the United States in comparison with other populations, we used allele frequencies to calculate the homozygosity for 11 populations where >90% ascertainment has been obtained. The United States was shown to contain one of the most heterogeneous populations, with homozygosity values similar to Sicily and ethnically mixed sample populations in Europe. The extent of allelic heterogeneity must be a major determining factor in the choice of mutation-detection methodology for molecular diagnosis in PAH deficiency. 47 refs., 1 fig., 5 tabs.

  18. Novel Mutations in Two Saudi Patients with Congenital Retinal Dystrophy

    OpenAIRE

    Leen Abu Safieh; Al-Otaibi, Humoud M.; Richard Alan Lewis; Igor Kozak

    2016-01-01

    To report novel mutations in two Saudi children with clinical features of Leber congenital amaurosis (LCA) and Alström syndrome. Case reports. Case 1 was a child with phenotypic features of LCA including oculodigital sign, bilateral enophthalmos, nystagmus, pale disc, and retinal changes. Direct sequencing of the coding sequence of GUCY2D revealed a missense mutation affecting highly conserved position (c. 743C > T; p.S248 L). Case 2 describes a girl with marked nystagmus, photophobia, and re...

  19. WRN mutations in Werner syndrome patients: genomic rearrangements, unusual intronic mutations and ethnic-specific alterations.

    Science.gov (United States)

    Friedrich, Katrin; Lee, Lin; Leistritz, Dru F; Nürnberg, Gudrun; Saha, Bidisha; Hisama, Fuki M; Eyman, Daniel K; Lessel, Davor; Nürnberg, Peter; Li, Chumei; Garcia-F-Villalta, María J; Kets, Carolien M; Schmidtke, Joerg; Cruz, Vítor Tedim; Van den Akker, Peter C; Boak, Joseph; Peter, Dincy; Compoginis, Goli; Cefle, Kivanc; Ozturk, Sukru; López, Norberto; Wessel, Theda; Poot, Martin; Ippel, P F; Groff-Kellermann, Birgit; Hoehn, Holger; Martin, George M; Kubisch, Christian; Oshima, Junko

    2010-07-01

    Werner syndrome (WS) is an autosomal recessive segmental progeroid syndrome caused by null mutations at the WRN locus, which codes for a member of the RecQ family of DNA helicases. Since 1988, the International Registry of Werner syndrome had enrolled 130 molecularly confirmed WS cases from among 110 worldwide pedigrees. We now report 18 new mutations, including two genomic rearrangements, a deep intronic mutation resulting in a novel exon, a splice consensus mutation leading to utilization of the nearby splice site, and two rare missense mutations. We also review evidence for founder mutations among various ethnic/geographic groups. Founder WRN mutations had been previously reported in Japan and Northern Sardinia. Our Registry now suggests characteristic mutations originated in Morocco, Turkey, The Netherlands and elsewhere.

  20. Report of a novel OCA2 gene mutation and an investigation of OCA2 variants on melanoma risk in a familial melanoma pedigree.

    Science.gov (United States)

    Hawkes, Jason E; Cassidy, Pamela B; Manga, Prashiela; Boissy, Raymond E; Goldgar, David; Cannon-Albright, Lisa; Florell, Scott R; Leachman, Sancy A

    2013-01-01

    Oculocutaneous albinism type 2 (OCA2) is caused by mutations of the OCA2 gene. Individuals affected by OCA2 as well as other types of albinism are at a significantly increased risk for sun-induced skin-cancers, including malignant melanoma (MM). To identify the molecular etiology of oculocutaneous albinism in a previously uncharacterized melanoma pedigree and to investigate the relationship between two OCA2 variants and melanoma predisposition in this pedigree. DNA and RNA were isolated from the peripheral blood of seven patients in a familial melanoma pedigree. Electron microscopy was performed on the individual with clinical oculocutaneous albinism. OCA2, TYRP1, MC1R, CDKN2A/p16, CDKN2A/p19ARF, and CDK4 genes were sequenced in affected individuals. The relationship between OCA2 variants and melanoma was assessed using a pedigree likelihood-based method. The proband was determined to be an OCA2 compound heterozygous mutation carrier with a previously reported conservative missense mutation (V443I) and a novel non-conservative missense mutation (L734R). The pedigree contained individuals diagnosed with both cutaneous and iris melanoma. Based on co-segregation analysis, the odds of these OCA2 variants being high penetrance loci for melanoma was: 1.3-to-1 if we include the iris melanoma as affected and 6.5-to-1 if we only consider cutaneous melanoma as affected. The discovery of this novel OCA2 variant adds to the body of evidence on the detrimental effects of OCA2 gene mutations on pigmentation, supports existing GWAS data on the relevance of the OCA2 gene in melanoma predisposition, and may ultimately assist in the development of targeted molecular therapies in the treatment of OCA and melanoma. Copyright © 2012. Published by Elsevier Ireland Ltd.

  1. The Bioinformatics Report of Mutation Outcome on NADPH Flavin Oxidoreductase Protein Sequence in Clinical Isolates of H. pylori.

    Science.gov (United States)

    Mirzaei, Nasrin; Poursina, Farkhondeh; Moghim, Sharareh; Ghaempanah, Abdol Majid; Safaei, Hajieh Ghasemian

    2016-05-01

    frxA gene has been implicated in the metronidazole nitro reduction by H. pylori. Alternatively, frxA is expected to contribute to the protection of urease and to the in vivo survival of H. pylori. The aim of present study is to report the mutation effects on the frxA protein sequence in clinical isolates of H. pylori in our community. Metronidazole resistance was proven in 27 of 48 isolates. glmM and frxA genes were used for molecular confirmation of H. pylori isolates. The primer set for detection of whole sequence of frxA gene for the effect of mutation on protein sequence was used. DNA and protein sequence evaluation and analysis were done by blast, Clustal Omega, and T COFFEE programs. Then, FrxA protein sequences from six metronidazole-resistant clinical isolates were analyzed by web-based bioinformatics tools. The result of six metronidazole-resistant clinical isolates in comparison with strain 26695 showed ten missense mutations. The result with the STRING program revealed that no change was seen after alterations in these sequences. According to consensus data involving four methods, residue substitutions at 40, 13, and 141 increase the stability of protein sequence after mutation, while other alterations decrease. Residue substitutions at 40, 43, 141, 138, 169, and 179 are deleterious, while, V7I, Q10R, V34I, and V96I alterations are neutral. As FrxA contribute to survival of bacterium and in regard to the effect of mutations on protein function, it might affect the survival and bacterium phenotype and it need to be studied more. Also, none of the stability prediction tool is perfect; iStable is the best predictor method among all methods.

  2. Alternating hemiplegia of childhood-related neural and behavioural phenotypes in Na+,K+-ATPase α3 missense mutant mice.

    Directory of Open Access Journals (Sweden)

    Greer S Kirshenbaum

    Full Text Available Missense mutations in ATP1A3 encoding Na(+,K(+-ATPase α3 have been identified as the primary cause of alternating hemiplegia of childhood (AHC, a motor disorder with onset typically before the age of 6 months. Affected children tend to be of short stature and can also have epilepsy, ataxia and learning disability. The Na(+,K(+-ATPase has a well-known role in maintaining electrochemical gradients across cell membranes, but our understanding of how the mutations cause AHC is limited. Myshkin mutant mice carry an amino acid change (I810N that affects the same position in Na(+,K(+-ATPase α3 as I810S found in AHC. Using molecular modelling, we show that the Myshkin and AHC mutations display similarly severe structural impacts on Na(+,K(+-ATPase α3, including upon the K(+ pore and predicted K(+ binding sites. Behavioural analysis of Myshkin mice revealed phenotypic abnormalities similar to symptoms of AHC, including motor dysfunction and cognitive impairment. 2-DG imaging of Myshkin mice identified compromised thalamocortical functioning that includes a deficit in frontal cortex functioning (hypofrontality, directly mirroring that reported in AHC, along with reduced thalamocortical functional connectivity. Our results thus provide validation for missense mutations in Na(+,K(+-ATPase α3 as a cause of AHC, and highlight Myshkin mice as a starting point for the exploration of disease mechanisms and novel treatments in AHC.

  3. Novel mutations in the transmembrane natriuretic peptide receptor NPR-B gene in four Indian families with acromesomelic dysplasia, type Maroteaux

    Indian Academy of Sciences (India)

    PRIYANKA SRIVASTAVA; MONI TUTEJA; ASHWIN DALAL; KAUSIK MANDAL; SHUBHA R. PHADKE

    2016-12-01

    Acromesomelic dysplasia, type Maroteaux is a disorder characterized by disproportionate short stature predominantly affecting the middle and distal segments of the upper and lower limbs. It is an autosomal recessive disorder due to mutation in NPR2 gene which impairs skeletal growth. To screen the mutations in the gene NPR2, all of its coding exons and splice junction sites were PCR amplified from genomic DNA of affected individuals of four families and sequenced. Four homozygous mutations in four different families were identified. These include three novel mutations including a deletion frameshift mutation (p.Cys586Ter), one nonsense mutation (p.Arg479Ter), one missense mutation (p.Val187Asp) and one reported missense mutation (p.Tyr338Cys). The study describes phenotypes of Indian patients and expands the mutation spectrum of the disorder.

  4. MPL Baltimore mutation and thrombocytosis: case report and literature review.

    Science.gov (United States)

    Shkalim-Zemer, Vered; Dgany, Orly; Krasnov, Tanya; Yacobovich, Joanne; Tamary, Hannah

    2013-04-01

    Thrombocytosis is a common finding and is a frequent cause of referral for further investigation. The MPL Baltimore (Lys39Asn) mutation has been reported as a cause of thrombocytosis in 7% of African Americans. We describe an 11-month-old Ethiopian Jewish boy referred for evaluation of thrombocytosis who was found to be homozygous for MPL Baltimore. So far, there is no indication whether patients with thrombocytosis who have this mutation, particularly homozygotes, are at increased risk of thrombotic or hemorrhagic complications. Nevertheless, this entity should be considered in the differential diagnosis of every patient with thrombocytosis, particularly those of African origin.

  5. De novo mutations in the motor domain of KIF1A cause cognitive impairment, spastic paraparesis, axonal neuropathy, and cerebellar atrophy

    NARCIS (Netherlands)

    Lee, Jae Ran; Srour, Myriam; Kim, Doyoun; Hamdan, Fadi F.; Lim, So Hee; Brunel-Guitton, Catherine; Décarie, Jean Claude; Rossignol, Elsa; Mitchell, Grant A.; Schreiber, Allison; Moran, Rocio; Van Haren, Keith; Richardson, Randal; Nicolai, Joost; Oberndorff, Karin M E J; Wagner, Justin D.; Boycott, Kym M.; Rahikkala, Elisa; Junna, Nella; Tyynismaa, Henna; Cuppen, Inge; Verbeek, Nienke E.; Stumpel, Connie T R M; Willemsen, Michel A.; de Munnik, Sonja A.; Rouleau, Guy A.; Kim, Eunjoon; Kamsteeg, Erik Jan; Kleefstra, Tjitske; Michaud, Jacques L.

    2015-01-01

    KIF1A is a neuron-specific motor protein that plays important roles in cargo transport along neurites. Recessive mutations in KIF1A were previously described in families with spastic paraparesis or sensory and autonomic neuropathy type-2. Here, we report 11 heterozygous de novo missense mutations (p

  6. A Gly482Ser missense mutation in the peroxisome proliferator-activated receptor gamma coactivator-1 is associated with altered lipid oxidation and early insulin secretion in Pima Indians

    DEFF Research Database (Denmark)

    Muller, Yunhua Li; Bogardus, Clifton; Pedersen, Oluf

    2003-01-01

    Peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) is a transcriptional coactivator of peroxisome proliferator-activated receptor gamma and alpha, which play important roles in adipogenesis and lipid metabolism. A single nucleotide polymorphism within the coding region...... Indians. There was no association of the Gly482Ser polymorphism with either type 2 diabetes or BMI (n = 984). However, among nondiabetic Pima Indians (n = 183-201), those with the Gly/Gly genotype had a lower mean insulin secretory response to intravenous and oral glucose and a lower mean rate of lipid...... oxidation (over 24 h in a respiratory chamber) despite a larger mean subcutaneous abdominal adipocyte size and a higher mean plasma free fatty acid concentration. These data indicate that the Gly482Ser missense polymorphism in PGC-1 has metabolic consequences on lipid metabolism that could influence insulin...

  7. Epidermolytic palmoplantar keratoderma in a Hispanic kindred resulting from a mutation in the keratin 9 gene.

    Science.gov (United States)

    Warmuth, I; Cserhalmi-Friedman, P B; Schneiderman, P; Grossman, M E; Christiano, A M

    2000-05-01

    Epidermolytic palmoplantar keratoderma (EPPK) is a localized keratinization disorder caused by mutations in the highly conserved coil 1A domain of the keratin 9 gene, KRT9. We present a Hispanic pedigree spanning three generations, with affected individuals in all generations. Using polymerase chain reaction amplification and direct sequencing we demonstrated a previously reported missense mutation in KRT9, which is expressed almost exclusively in the skin of palms and soles. The C-->T missense mutation R162W changes a basic amino acid (arginine) to a neutral amino acid (tryptophan). We describe this mutation in a Hispanic pedigree with EPPK for the first time, extending the finding of this mutation in other genetic backgrounds, and demonstrating the prevalence of this mutation in diverse populations.

  8. Functional characterization of the TSC2 c.3598C > T (p.R1200W) missense mutation that co-segregates with tuberous sclerosis complex in mildly affected kindreds

    NARCIS (Netherlands)

    Wentink, M.; Nellist, M.; Hoogeveen-Westerveld, M.; Zonnenberg, B.; van der Kolk, D.M.; van Essen, T.; Park, S-M; Woods, G.; Cohn-Hokke, P.; Brussel, W.; Smeets, E.; Brooks, A.; Halley, D.; van den Ouweland, A.; Maat-Kievit, A.

    2012-01-01

    Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a combination of neurological symptoms and hamartomatous growths, and caused by mutations in the TSC1 and TSC2 genes. Overall, TSC2 mutations are associated with a more severe disease phenotype. We identified the c.

  9. Phenotype of Usher syndrome type Ⅱ assosiated with compound missense mutations of c.721 C>T and c.1969 C>T in MYO7A in a Chinese Usher syndrome family

    Institute of Scientific and Technical Information of China (English)

    Wei; Zhai; Xin; Jin; Yan; Gong; Ling-Hui; Qu; Chen; Zhao; Zhao-Hui; Li

    2015-01-01

    ·AIM: To identify the pathogenic mutations in a Chinese pedigree affected with Usher syndrome type II(USH2).· METHODS: The ophthalmic examinations and audiometric tests were performed to ascertain the phenotype of the family. To detect the genetic defect,exons of 103 known RDs-associated genes including 12 Usher syndrome(USH) genes of the proband were captured and sequencing analysis was performed to exclude known genetic defects and find potential pathogenic mutations. Subsequently, candidate mutations were validated in his pedigree and 100 normal controls using polymerase chain reaction(PCR) and Sanger sequencing.·RESULTS: The patient in the family occurred hearing loss(HL) and retinitis pigmentosa(RP) without vestibular dysfunction, which were consistent with standards of classification for USH2. He carried the compound heterozygous mutations, c.721 C >T and c.1969 C >T, in the MYO7 A gene and the unaffected members carried only one of the two mutations. The mutations were not present in the 100 normal controls.· CONCLUSION: We suggested that the compound heterozygous mutations of the MYO7 A could lead to USH2, which had revealed distinguished clinical phenotypes associated with MYO7 A and expanded the spectrum of clinical phenotypes of the MYO7 A mutations.

  10. Phenotype of Usher syndrome type II assosiated with compound missense mutations of c.721 C>T and c.1969 C>T in MYO7A in a Chinese Usher syndrome family

    Directory of Open Access Journals (Sweden)

    Wei Zhai

    2015-08-01

    Full Text Available AIM:To identify the pathogenic mutations in a Chinese pedigree affected with Usher syndrome type II (USH2.METHODS:The ophthalmic examinations and audiometric tests were performed to ascertain the phenotype of the family. To detect the genetic defect, exons of 103 known RDs -associated genes including 12 Usher syndrome (USH genes of the proband were captured and sequencing analysis was performed to exclude known genetic defects and find potential pathogenic mutations. Subsequently, candidate mutations were validated in his pedigree and 100 normal controls using polymerase chain reaction (PCR and Sanger sequencing.RESULTS:The patient in the family occurred hearing loss (HL and retinitis pigmentosa (RP without vestibular dysfunction, which were consistent with standards of classification for USH2. He carried the compound heterozygous mutations, c.721 C>T and c.1969 C>T, in the MYO7A gene and the unaffected members carried only one of the two mutations. The mutations were not present in the 100 normal controls.CONCLUSION:We suggested that the compound heterozygous mutations of the MYO7A could lead to USH2, which had revealed distinguished clinical phenotypes associated with MYO7A and expanded the spectrum of clinical phenotypes of the MYO7A mutations.

  11. Frontotemporal dementia caused by CHMP2B mutations

    DEFF Research Database (Denmark)

    Isaacs, A M; Johannsen, P; Holm, I;

    2011-01-01

    CHMP2B mutations are a rare cause of autosomal dominant frontotemporal dementia (FTD). The best studied example is frontotemporal dementia linked to chromosome 3 (FTD-3) which occurs in a large Danish family, with a further CHMP2B mutation identified in an unrelated Belgian familial FTD patient. ...... features of FTD caused by CHMP2B truncation mutations as well as new brain imaging and neuropathological findings. Finally, we collate the current data on CHMP2B missense mutations, which have been reported in FTD and motor neuron disease....

  12. Functional analysis helps to define KCNC3 mutational spectrum in Dutch ataxia cases.

    Directory of Open Access Journals (Sweden)

    Anna Duarri

    Full Text Available Spinocerebellar ataxia type 13 (SCA13 is an autosomal dominantly inherited neurodegenerative disorder of the cerebellum caused by mutations in the voltage gated potassium channel KCNC3. To identify novel pathogenic SCA13 mutations in KCNC3 and to gain insights into the disease prevalence in the Netherlands, we sequenced the entire coding region of KCNC3 in 848 Dutch cerebellar ataxia patients with familial or sporadic origin. We evaluated the pathogenicity of the identified variants by co-segregation analysis and in silico prediction followed by biochemical and electrophysiological studies. We identified 19 variants in KCNC3 including 2 non-coding, 11 missense and 6 synonymous variants. Two missense variants did not co-segregate with the disease and were excluded as potentially disease-causing mutations. We also identified the previously reported p.R420H and p.R423H mutations in our cohort. Of the remaining 7 missense variants, functional analysis revealed that 2 missense variants shifted Kv3.3 channel activation to more negative voltages. These variations were associated with early disease onset and mild intellectual disability. Additionally, one other missense variant shifted channel activation to more positive voltages and was associated with spastic ataxic gait. Whereas, the remaining missense variants did not change any of the channel characteristics. Of these three functional variants, only one variant was in silico predicted to be damaging and segregated with disease. The other two variants were in silico predicted to be benign and co-segregation analysis was not optimal or could only be partially confirmed. Therefore, we conclude that we have identified at least one novel pathogenic mutation in KCNC3 that cause SCA13 and two additionally potential SCA13 mutations. This leads to an estimate of SCA13 prevalence in the Netherlands to be between 0.6% and 1.3%.

  13. Carpenter syndrome: extended RAB23 mutation spectrum and analysis of nonsense-mediated mRNA decay

    OpenAIRE

    2011-01-01

    Abstract Carpenter syndrome, a rare autosomal recessive disorder characterized by a combination of craniosynostosis, polysyndactyly, obesity, and other congenital malformations, is caused by mutations in RAB23, encoding a member of the Rab-family of small GTPases. In 15 out of 16 families previously reported, the disease was caused by homozygosity for truncating mutations, and currently only a single missense mutation has been identified in a compound heterozygote. Here, we describ...

  14. A novel mutation (G114V) in the prion protein gene in a family with inherited prion disease.

    Science.gov (United States)

    Rodriguez, M-M; Peoc'h, K; Haïk, S; Bouchet, C; Vernengo, L; Mañana, G; Salamano, R; Carrasco, L; Lenne, M; Beaudry, P; Launay, J-M; Laplanche, J-L

    2005-04-26

    Inherited prion diseases are characterized by mutations in the PRNP gene encoding the prion protein (PrP). We report a novel missense mutation in the PRNP gene (resulting in a G114V mutation in PrP) in members of a Uruguayan family with clinical and histopathologic features of prion disease. Affected individuals were characterized by an early age at onset, initial neuropsychiatric symptoms, late dementia with prominent pyramidal and extrapyramidal symptoms, and long disease duration.

  15. Tufting enteropathy with EpCAM mutation: case report

    Directory of Open Access Journals (Sweden)

    Karla Lais Pêgas

    2014-06-01

    Full Text Available Tufting enteropathy (TE, also known as intestinal epithelial dysplasia (IED, is a rare congenital enteropathy related to an earlyonset of severe intractable diarrhea due to specific abnormalities of the intestinal epithelium and mutations of the EpCAM gene. TE is characterized by clinical and histological heterogeneity, such as with low or without mononuclear cell infiltration of the lamina propria, and abnormalities of basement membrane. TE can be associated with malformations, other epithelial diseases, or to abnormal enterocytes development and/or differentiation. The authors report a case of a Brazilian child with TE associated with c.556-14A>G mutation in the EpCAM gene (NM_002354.2.

  16. Relationship of myocardial damage of chronic and latent Keshan disease with desmin gene exon6 A360P missense mutation%desmin基因exon6 A360P错义突变与慢型及潜在型克山病心肌损伤的关系

    Institute of Scientific and Technical Information of China (English)

    张洁; 刘作功; 郭雄

    2010-01-01

    目的 探讨desmin基因exon6 A360P错义突变与克山病心肌损伤的关系及exon6 A360P错义突变是否是慢型及潜在型克山病损伤的易感基因.方法 在陕西省克山病病区黄陵县店头镇和非病区西安市长安区,采用单纯随机抽样的方法,抽取年龄相匹配的慢型和潜在型克山病患者(病例组)30例及病区(内对照组)和非病区对照(外对照组)各30例.采集外周血5 ml,乙二胺四乙酸(EDTA)抗凝,盐析法制备基因组DNA.采用PCR方法,用特异性的Bsp1286 Ⅰ内切酶对可能发生突变的exon6位点进行酶切.设内对照,在desmin基因exon4位点进行酶切,判定标准为在122 bp和60 bp处各出现1个条带.琼脂糖凝胶电泳分析desmin基因exon6 A360P错义突变位点,判定标准为desmin基因exon6位点酶切后在184 bp和66 bp处各出现1个条带.结果 琼脂糖凝胶电泳结果显示,内对照desmin基因exon4在Bsp1286 Ⅰ酶切前,在182 bp处仅出现1条条带;在酶切后,被切成2个片段,在122 bp和60 bp处各出现1个条带.慢型及潜在型克山病患者desmin基因exon6在Bsp1286 Ⅰ酶切前和酶切后,均在250 bp处出现了1个条带;病区和非病区对照组desmin基因酶切后,也是在250 bp处出现了1个条带.3组结果相同,desmin基因exon6没有被Bsp1286 Ⅰ酶切开,A360P没有发生错义突变.结论 慢型和潜在型克山病患者未检出desmin基因exon6 A360P错义突变位点,desmin基因exon6 A360P错义突变不是克山病心肌损伤的易感基因.%Objective To survey the relationship between myocardial damage of chronic and latent Keshan disease with A360P missense mutation in desmin gene exon6. Methods By clinical epidemiology method,30 cases had been collected randomly among chronic Keshan disease patients and 30 cases equally among healthy adults (inner control groups) in Diantou town,Huangling county,Shaanxi province,a Keshan disease area,and 30 cases among health adults(outer control group) in Chang

  17. A novel gamma-sarcoglycan mutation causing childhood onset, slowly progressive limb girdle muscular dystrophy

    NARCIS (Netherlands)

    van der Kooi, AJ; de Visser, M; van Meegen, M; Ginjaar, HB; van Essen, AJ; Jennekens, FGI; Jongen, PJH; Leschot, NJ; Bolhuis, PA

    1998-01-01

    Limb girdle muscular dystrophy is a heterogeneous group of disorders. One autosomal recessive subtype, LGMD2C, has been linked to chromosome 13, and is caused by gamma-sarcoglycan deficiency in muscle. This report describes a novel missense mutation identified in a large consanguineous Dutch family

  18. A family with permanent neonatal diabetes due to a novel mutation in INS gene.

    Science.gov (United States)

    Dimova, Rumyana; Tankova, Tsvetalina; Gergelcheva, Ivelina; Tournev, Ivailo; Konstantinova, Maya

    2015-05-01

    In this report we present a family with permanent neonatal diabetes, heterozygous for a novel INS gene missense mutation, p.A24V, manifested with marked hyperglycemia and ketoacidosis, unstable glycemic control, requiring insulin therapy, rapid progression of long-term complications and accompanying physical pathological signs and brain lesions.

  19. Hypomaturation amelogenesis imperfecta caused by a novel SLC24A4 mutation.

    Science.gov (United States)

    Herzog, Curtis R; Reid, Bryan M; Seymen, Figen; Koruyucu, Mine; Tuna, Elif Bahar; Simmer, James P; Hu, Jan C-C

    2015-02-01

    In this case report of autosomal recessive pigmented hypomaturation amelogenesis imperfecta (AI), we identify a novel homozygous missense mutation (g.165151 T>G; c.1317 T>G; p.Leu436 Arg) in SLC24A4, a gene encoding a potassium-dependent sodium-calcium exchanger that is critical for hardening dental enamel during tooth development.

  20. A novel gamma-sarcoglycan mutation causing childhood onset, slowly progressive limb girdle muscular dystrophy

    NARCIS (Netherlands)

    van der Kooi, AJ; de Visser, Marianne; van Meegen, M; Ginjaar, HB; van Essen, AJ; Jennekens, FGI; Jongen, PJH; Leschot, NJ; Bolhuis, PA

    Limb girdle muscular dystrophy is a heterogeneous group of disorders. One autosomal recessive subtype, LGMD2C, has been linked to chromosome 13, and is caused by gamma-sarcoglycan deficiency in muscle. This report describes a novel missense mutation identified in a large consanguineous Dutch family

  1. Hypomaturation Amelogenesis Imperfecta Caused By A Novel SLC24A4 Mutation

    Science.gov (United States)

    Herzog, Curtis R.; Reid, Bryan M.; Seymen, Figen; Koruyucu, Mine; Tuna, Elif Bahar; Simmer, James P.; Hu, Jan C-C.

    2014-01-01

    In this case report of autosomal recessive pigmented hypomaturation amelogenesis imperfecta (AI), we identify a novel homozygous missense mutation (g.165151T>G; c.1317T>G; p.Leu436Arg) in SLC24A4, a gene encoding a potassium-dependent sodium-calcium exchanger that is critical for hardening dental enamel during tooth development. PMID:25442250

  2. Mutational analysis of the PRYSPRY domain of pyrin and implications for familial mediterranean fever (FMF).

    Science.gov (United States)

    Goulielmos, G N; Fragouli, E; Aksentijevich, I; Sidiropoulos, P; Boumpas, D T; Eliopoulos, E

    2006-07-14

    Familial Mediterranean fever (FMF) is an autosomal, recessively inherited disease, characterized by recurrent fever and serositis that affects mainly patients of the Mediterranean basin. The gene responsible for FMF, named MEFV, was cloned and several missense mutations were found to be responsible for the disease. Based on a recent molecular analysis of MEFV gene mutations in 43 patients from Crete aiming to correlate specific genotypes and clinical manifestations of FMF, we were prompted to construct a three-dimensional model (3-D model) of the PRYSPRY domain of pyrin. The majority of the known MEFV mutations located on this domain have been classified, according to disease severity, and localized on this 3-D model. The functional consequences of these mutations and their implications on disease severity are discussed. Moreover, we report a putative novel missense mutation, S702C, which we identified in exon 10 of the MEFV gene and localized on the constructed 3-D model.

  3. Hypomyelinating Leukodystrophy due to HSPD1 Mutations

    DEFF Research Database (Denmark)

    Schioldan Kusk, Maria; Damgaard, Bodil; Risom, Lotte

    2016-01-01

    The hypomyelinating leukodystrophies (HMLs) encompass the X-linked Pelizaeus-Merzbacher disease (PMD) caused by PLP1 mutations and known as the classical form of HML as well as Pelizaeus-Merzbacher-like disease (PMLD) (Online Mendelian Inheritance in Man [OMIM] 608804 and OMIM 260600) due to GJC2...... mutations. In addition, mutations in at least 10 other genes are known to cause HMLs. In 2008, an Israeli family with clinical and neuroimaging findings similar to those found in PMD was reported. The patients were found to have a homozygous missense mutation in HSPD1, encoding the mitochondrial heat......-shock protein 60 (Hsp60), and the disorder was defined as the autosomal recessive mitochondrial Hsp60 chaperonopathy (MitCHAP-60) disease. We here report the first case of this severe neurodegenerative disease since it was first described. Given the fact that the families carried the same mutation our patient...

  4. A single missense mutation in a coiled-coil domain of Escherichia coli ribosomal protein S2 confers a thermosensitive phenotype that can be suppressed by ribosomal protein S1.

    Science.gov (United States)

    Aseev, Leonid V; Chugunov, Anton O; Efremov, Roman G; Boni, Irina V

    2013-01-01

    Ribosomal protein S2 is an essential component of translation machinery, and its viable mutated variants conferring distinct phenotypes serve as a valuable tool in studying the role of S2 in translation regulation. One of a few available rpsB mutants, rpsB1, shows thermosensitivity and ensures enhanced expression of leaderless mRNAs. In this study, we identified the nature of the rpsB1 mutation. Sequencing of the rpsB1 allele revealed a G-to-A transition in the part of the rpsB gene which encodes a coiled-coil domain of S2. The resulting E132K substitution resides in a highly conserved site, TKKE, a so-called N-terminal capping box, at the beginning of the second alpha helix. The protruding coiled-coil domain of S2 is known to provide binding with 16S rRNA in the head of the 30S subunit and, in addition, to interact with a key mRNA binding protein, S1. Molecular dynamics simulations revealed a detrimental impact of the E132K mutation on the coiled-coil structure and thereby on the interactions between S2 and 16S rRNA, providing a clue for the thermosensitivity of the rpsB1 mutant. Using a strain producing a leaderless lacZ transcript from the chromosomal lac promoter, we demonstrated that not only the rpsB1 mutation generating S2/S1-deficient ribosomes but also the rpsA::IS10 mutation leading to partial deficiency in S1 alone increased translation efficiency of the leaderless mRNA by about 10-fold. Moderate overexpression of S1 relieved all these effects and, moreover, suppressed the thermosensitive phenotype of rpsB1, indicating the role of S1 as an extragenic suppressor of the E132K mutation.

  5. TBK1 Mutation Spectrum in an Extended European Patient Cohort with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis.

    Science.gov (United States)

    van der Zee, Julie; Gijselinck, Ilse; Van Mossevelde, Sara; Perrone, Federica; Dillen, Lubina; Heeman, Bavo; Bäumer, Veerle; Engelborghs, Sebastiaan; De Bleecker, Jan; Baets, Jonathan; Gelpi, Ellen; Rojas-García, Ricardo; Clarimón, Jordi; Lleó, Alberto; Diehl-Schmid, Janine; Alexopoulos, Panagiotis; Perneczky, Robert; Synofzik, Matthis; Just, Jennifer; Schöls, Ludger; Graff, Caroline; Thonberg, Håkan; Borroni, Barbara; Padovani, Alessandro; Jordanova, Albena; Sarafov, Stayko; Tournev, Ivailo; de Mendonça, Alexandre; Miltenberger-Miltényi, Gabriel; Simões do Couto, Frederico; Ramirez, Alfredo; Jessen, Frank; Heneka, Michael T; Gómez-Tortosa, Estrella; Danek, Adrian; Cras, Patrick; Vandenberghe, Rik; De Jonghe, Peter; De Deyn, Peter P; Sleegers, Kristel; Cruts, Marc; Van Broeckhoven, Christine; Goeman, Johan; Nuytten, Dirk; Smets, Katrien; Robberecht, Wim; Damme, Philip Van; Bleecker, Jan De; Santens, Patrick; Dermaut, Bart; Versijpt, Jan; Michotte, Alex; Ivanoiu, Adrian; Deryck, Olivier; Bergmans, Bruno; Delbeck, Jean; Bruyland, Marc; Willems, Christiana; Salmon, Eric; Pastor, Pau; Ortega-Cubero, Sara; Benussi, Luisa; Ghidoni, Roberta; Binetti, Giuliano; Hernández, Isabel; Boada, Mercè; Ruiz, Agustín; Sorbi, Sandro; Nacmias, Benedetta; Bagnoli, Silvia; Sorbi, Sandro; Sanchez-Valle, Raquel; Llado, Albert; Santana, Isabel; Rosário Almeida, Maria; Frisoni, Giovanni B; Maetzler, Walter; Matej, Radoslav; Fraidakis, Matthew J; Kovacs, Gabor G; Fabrizi, Gian Maria; Testi, Silvia

    2017-03-01

    We investigated the mutation spectrum of the TANK-Binding Kinase 1 (TBK1) gene and its associated phenotypic spectrum by exonic resequencing of TBK1 in a cohort of 2,538 patients with frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), or FTD plus ALS, ascertained within the European Early-Onset Dementia Consortium. We assessed pathogenicity of predicted protein-truncating mutations by measuring loss of RNA expression. Functional effect of in-frame amino acid deletions and missense mutations was further explored in vivo on protein level and in vitro by an NFκB-induced luciferase reporter assay and measuring phosphorylated TBK1. The protein-truncating mutations led to the loss of transcript through nonsense-mediated mRNA decay. For the in-frame amino acid deletions, we demonstrated loss of TBK1 or phosphorylated TBK1 protein. An important fraction of the missense mutations compromised NFκB activation indicating that at least some functions of TBK1 are lost. Although missense mutations were also present in controls, over three times more mutations affecting TBK1 functioning were found in the mutation fraction observed in patients only, suggesting high-risk alleles (P = 0.03). Total mutation frequency for confirmed TBK1 LoF mutations in the European cohort was 0.7%, with frequencies in the clinical subgroups of 0.4% in FTD, 1.3% in ALS, and 3.6% in FTD-ALS.

  6. Infantile Systemic Hyalinosis: A Case Report with a Novel Mutation

    Directory of Open Access Journals (Sweden)

    Siham Al Sinani

    2013-01-01

    Full Text Available Infantile Systemic Hyalinosis (ISH (OMIM 236490 is a rare, progressive and fatal autosomal recessive disorder characterized by multiple subcutaneous skin nodules, gingival hypertrophy, osteopenia, joint contractures, failure to thrive, diarrhea with protein losing enteropathy, and frequent infections. There is diffuse deposition of hyaline material in the skin, gastrointestinal tract, muscle and endocrine glands. It is caused by mutations in the ANTXR2 (also known as CMG2 gene, which encodes a trans-membranous protein involved in endothelial development and basement membrane-extracellular matrix assembly. We describe a child with classical features of ISH presenting in infancy with severe chronic debilitating pain and progressive joint contractures. The diagnosis was confirmed by molecular DNA sequencing of ANTXR2 gene which revealed a novel homozygous mutation not previously reported; 79 bp deletion of the entire exon 11 (c.867_945del, p.E289DfsX22. Although this is the first reported case of ISH in Oman, we believe that the disease is under-diagnosed since children affected with this lethal disease pass away early in infancy prior to establishing a final diagnosis.

  7. Rapid identification of HEXA mutations in Tay-Sachs patients.

    Science.gov (United States)

    Giraud, Carole; Dussau, Jeanne; Azouguene, Emilie; Feillet, François; Puech, Jean-Philippe; Caillaud, Catherine

    2010-02-19

    Tay-Sachs disease (TSD) is a recessively inherited neurodegenerative disorder due to mutations in the HEXA gene resulting in a beta-hexosaminidase A (Hex A) deficiency. The purpose of this study was to characterize the molecular abnormalities in patients with infantile or later-onset forms of the disease. The complete sequencing of the 14 exons and flanking regions of the HEXA gene was performed with a unique technical condition in 10 unrelated TSD patients. Eleven mutations were identified, including five splice mutations, one insertion, two deletions and three single-base substitutions. Four mutations were novel: two splice mutations (IVS8+5G>A, IVS2+4delAGTA), one missense mutation in exon 6 (c.621T>G (p.D207E)) and one small deletion (c.1211-1212delTG) in exon 11 resulting in a premature stop codon at residue 429. The c.621T>G missense mutation was found in a patient presenting an infantile form. Its putative role in the pathogenesis of TSD is suspected as residue 207 is highly conserved in human, mouse and rat. Moreover, structural modelling predicted changes likely to affect substrate binding and catalytic activity of the enzyme. The time-saving procedure reported here could be useful for the characterization of Tay-Sachs-causing mutations, in particular in non-Ashkenazi patients mainly exhibiting rare mutations.

  8. Identification of six pathogenic RAD51C mutations via mutational screening of 1228 Danish individuals with increased risk of hereditary breast and/or ovarian cancer

    DEFF Research Database (Denmark)

    Jønson, Lars; Ahlborn, Lise B; Steffensen, Ane Y;

    2016-01-01

    significance of missense and intronic variants was predicted by in silico analysis. We identified six families with a pathogenic mutation in RAD51C, including three frameshift mutations, one nonsense mutation, and 2 missense mutations. Overall, pathogenic RAD51C mutations were identified in 0.5 % of Danish...

  9. Systemic vascular phenotypes of Loeys-Dietz syndrome in a child carrying a de novo R381P mutation in TGFBR2: a case report.

    Science.gov (United States)

    Uike, Kiyoshi; Matsushita, Yuki; Sakai, Yasunari; Togao, Osamu; Nagao, Michinobu; Ishizaki, Yoshito; Nagata, Hazumu; Yamamura, Kenichiro; Torisu, Hiroyuki; Hara, Toshiro

    2013-11-12

    Loeys-Dietz syndrome, also known as Marfan syndrome type II, is a rare connective tissue disorder caused by dominant mutations in transforming growth factor-beta receptors (TGFBR1 and 2). We report a 7-year-old Japanese boy with Loeys-Dietz syndrome who carried a novel, de novo missense mutation in TGFBR2 (c.1142g > c, R381P). He showed dysmorphic faces and skeletal malformations that were typical in previous cases with Loeys-Dietz syndrome. The cardiac studies disclosed the presence of markedly dilated aortic root and patent ductus aorteriosus. The cranial magnetic resonance imaging (MRI) and angiography (MRA) detected the tortuous appearances of the bilateral middle cerebral and carotid arteries. This study depicts the systemic vascular phenotypes of a child with Loeys-Dietz syndrome that were caused by a novel heterozygous mutation of TGFR2. A large cohort with serial imaging studies for vascular phenotypes will be useful for delineating the genotype-phenotype correlations of Loeys-Dietz syndrome.

  10. A novel syndrome of autosomal-dominant hyperinsulinemic hypoglycemia linked to a mutation in the human insulin receptor gene

    DEFF Research Database (Denmark)

    Højlund, Kurt; Hansen, Torben; Lajer, Maria

    2004-01-01

    a missense mutation (Arg1174Gln) in the tyrosine kinase domain of the insulin receptor gene that cosegregated with the disease phenotype (logarithm of odds [LOD] score 3.21). In conclusion, we report a novel syndrome of autosomal-dominant hyperinsulinemic hypoglycemia. The findings demonstrate...

  11. Founder effect in the Horn of Africa for an insulin receptor mutation that may impair receptor recycling

    DEFF Research Database (Denmark)

    Raffan, E; Soos, M A; Rocha, N;

    2011-01-01

    Genetic insulin receptoropathies are a rare cause of severe insulin resistance. We identified the Ile119Met missense mutation in the insulin receptor INSR gene, previously reported in a Yemeni kindred, in four unrelated patients with Somali ancestry. We aimed to investigate a possible genetic...... founder effect, and to study the mechanism of loss of function of the mutant receptor....

  12. Audiometric and vestibular features in a second Dutch DFNA20/26 family with a novel mutation in ACTG1.

    NARCIS (Netherlands)

    Heer, A.M. de; Huygen, P.L.M.; Collin, R.W.J.; Oostrik, J.; Kremer, J.M.J.; Cremers, C.W.R.J.

    2009-01-01

    OBJECTIVES: We analyzed the phenotype in a 5-generation DFNA20/26 family with a novel missense mutation in the ACTG1 gene (c.151G>A) and compared the findings to previous reports on DFNA20/26 families. METHODS: Audiometric data were collected from the family members of a Dutch kindred with the no

  13. Analysis of missense variants in the PKHD1-gene in patients with autosomal recessive polycystic kidney disease (ARPKD).

    Science.gov (United States)

    Losekoot, Monique; Haarloo, Cathleen; Ruivenkamp, Claudia; White, Stefan J; Breuning, Martijn H; Peters, Dorien J M

    2005-11-01

    Autosomal recessive polycystic kidney disease (ARPKD) is a severe form of polycystic kidney disease characterized by enlarged kidneys and congenital hepatic fibrosis. Given the poor prognosis for the majority of children with the severe perinatal ARPKD phenotype, there is a regular request for prenatal testing. ARPKD is caused by mutations in the polycystic kidney and hepatic disease 1 (PKHD1) gene, which consists of 86 exons that are variably assembled into a number of alternatively spliced transcripts. The longest transcript, comprising 67 exons, encodes the protein fibrocystin/polyductin. We have set up mutation analysis by direct sequencing of these 67 exons. In 39 mainly Dutch families we identified: 11 nonsense mutations, 15 deletions/insertions, 5 splice site mutations, and 39 missense mutations. To classify missense variants we combined evolutionary conservation, using the human, chimpanzee, dog, mouse, chicken and frog Pkhd1 sequences, with the Grantham score for chemical differences. Thirty-three missense mutations were considered pathogenic and seven were classified as rare, probably pathogenic variants. In addition to sequence analysis, multiplex ligation-dependent probe amplification (MLPA) was used to identify multiple exon deletions. However, no large deletions in the PKHD1 gene were identified. In 31 index patients two mutations were found, in 6 patients one mutation was found, leading to a mutation detection rate of 87%. The analysis of amino acid conservation as well as applying the Grantham score for chemical differences allowed us to determine the pathogeneity for nearly all new missense mutations and thus proved to be useful tools to classify missense variants.

  14. The heterozygous A53T mutation in the alpha-synuclein gene in a Chinese Han patient with Parkinson disease: case report and literature review.

    Science.gov (United States)

    Xiong, Wei-Xi; Sun, Yi-Min; Guan, Rong-Yuan; Luo, Su-Shan; Chen, Chen; An, Yu; Wang, Jian; Wu, Jian-Jun

    2016-10-01

    The missense mutation A53T of alpha-synuclein gene (SNCA) was reported to be a rare but definite cause of sporadic and familial Parkinson disease (PD). It seemed to be restricted geographically in Greece and Italy. We aimed to identify the SNCA mutations in a Chinese PD cohort. Ninety-one early onset PD patients or familial PD probands were collected consecutively for the screening of PD-related genes. The genetic analysis was carried out by target sequencing of the exons and the corresponding flanking regions of the PD-related genes using Illumina HiSeq 2000 sequencer and further confirmed by Sanger sequencing or restriction fragment length polymorphism. Dosage mutations of exons in these genes were carried out by multiple ligation-dependent probe amplification. Among the 91 patients, we found only one heterozygous mutation of SNCA A53T, in a 23-year-old male patient with negative family history. The [(11)C]-2β-carbomethoxy-3β-(4-fluorophenyl) tropan (CFT) PET and PD-related spatial covariance pattern (PDRP) via [(18)F]-fluorodeoxyglucos (FDG) PET confirmed a typical pattern of PD. After examining his parents, we found his mother was an asymptomatic carrier, with declined hand dexterity detected by quantitative motor tests. Reduced dopamine transporter uptake of his mother was identified by CFT PET, and abnormal PDRP pattern was found by FDG PET. Our investigation expanded the clinical and genetic spectrum of Chinese PD patients, and we suggested SNCA mutations to be screened in familial and early onset Chinese PD patients.

  15. Rare missense variants within a single gene form yin yang haplotypes.

    Science.gov (United States)

    Curtis, David

    2016-01-01

    Yin yang haplotype pairs differ at every SNP. They would not be accounted for by population models that incorporate sequential mutation, with or without recombination. Previous reports have claimed that there is a tendency for common SNPs to form yin yang haplotypes more often than would be expected by sequential mutation or by a random sample of all possible haplotypic arrangements of alleles. In the course of analysing next-generation sequencing data, instances of yin yang haplotypes being formed by very rare variants within a single gene were observed. As an example, this report describes a completely yin yang haplotype formed by eight rare missense variants in the ABCA13 gene. Of 1000 genome subjects, 21 have a copy of the alternate allele at all eight of these positions and a single subject is homozygous for all of them. None of the other 1070 subjects possesses any of the altetrnates. Thus, the eight alternate alleles are always found together and never occur separately. The existence of such yin yang haplotypes has important implications for statistical methods for analysing rare variants. Also, they may be of use for gaining a better understanding of the history of human populations.

  16. Novel OPA1 mutation featuring spastic paraparesis and intestinal dysmotility

    Directory of Open Access Journals (Sweden)

    Mohamed Kazamel

    2014-01-01

    Full Text Available A 58-year-old man with optic atrophy, spastic paraparesis, axonal sensorimotor peripheral neuropathy and intestinal dysmotility harbors a novel heterozygous missense mutation in the mitochondrial import signal peptide of OPA1. The case underscores the role of OPA1 in the pathogenesis of spastic paraparesis, so far reported only in very few cases, and it adds intestinal dysmotility to the spectrum of adult-onset clinical manifestation of OPA1-associated disease.

  17. Identification of a Danish breast/ovarian cancer family double heterozygote for BRCA1 and BRCA2 mutations

    DEFF Research Database (Denmark)

    Steffensen, Ane Y; Jønson, Lars; Ejlertsen, Bent;

    2010-01-01

    Mutations in the two breast cancer susceptibility genes BRCA1 and BRCA2 are associated with increased risk of breast and ovarian cancer. Patients with mutations in both genes are rarely reported and often involve Ashkenazi founder mutations. Here we report the first identification of a Danish...... breast and ovarian cancer family heterozygote for mutations in the BRCA1 and BRCA2 genes. The BRCA1 nucleotide 5215G > A/c.5096G > A mutation results in the missense mutation Arg1699Gln, while the BRCA2 nucleotide 859 + 4A > G/c.631 + 4A > G is novel. Exon trapping experiments and reverse transcriptase...... (RT)-PCR analysis revealed that the BRCA2 mutation results in skipping of exon 7, thereby introducing a frameshift and a premature stop codon. We therefore classify the mutation as disease causing. Since the BRCA1 Arg1699Gln mutation is also suggested to be disease-causing, we consider this family...

  18. Ten novel HMGCL mutations in 24 patients of different origin with 3-hydroxy-3-methyl-glutaric aciduria.

    Science.gov (United States)

    Menao, Sebastián; López-Viñas, Eduardo; Mir, Cecilia; Puisac, Beatriz; Gratacós, Esther; Arnedo, María; Carrasco, Patricia; Moreno, Susana; Ramos, Mónica; Gil, María Concepción; Pié, Angeles; Ribes, Antonia; Pérez-Cerda, Celia; Ugarte, Magdalena; Clayton, Peter T; Korman, Stanley H; Serra, Dolors; Asins, Guillermina; Ramos, Feliciano J; Gómez-Puertas, Paulino; Hegardt, Fausto G; Casals, Nuria; Pié, Juan

    2009-03-01

    3-Hydroxy-3-methylglutaric aciduria is a rare autosomal recessive genetic disorder that affects ketogenesis and L-leucine catabolism. The clinical acute symptoms include vomiting, convulsions, metabolic acidosis, hypoketotic hypoglycaemia and lethargy. To date, 33 mutations in 100 patients have been reported in the HMGCL gene. In this study 10 new mutations in 24 patients are described. They include: 5 missense mutations: c.109G>A, c.425C>T, c.521G>A, c.575T>C and c.598A>T, 2 nonsense mutations: c.242G>A and c.559G>T, one small deletion: c.853delC, and 2 mutations in intron regions: c.497+4A>G and c.750+1G>A. Two prevalent mutations were detected, 109G>T (E37X) in 38% of disease alleles analyzed and c.504_505delCT in 10% of them. Although patients are mainly of European origin (71%) and mostly Spanish (54%), the group is ethnically diverse and includes, for the first time, patients from Pakistan, Palestine and Ecuador. We also present a simple, efficient method to express the enzyme and we analyze the possible functional effects of missense mutations. The finding that all identified missense mutations cause a >95% decrease in the enzyme activity, indicates that the disease appears only in very severe genotypes."

  19. Missense Mutation of POU Domain Class 3 Transcription Factor 3 in Pou3f3L423P Mice Causes Reduced Nephron Number and Impaired Development of the Thick Ascending Limb of the Loop of Henle

    Science.gov (United States)

    Rieger, Alexandra; Kemter, Elisabeth; Kumar, Sudhir; Popper, Bastian; Aigner, Bernhard; Wolf, Eckhard; Wanke, Rüdiger; Blutke, Andreas

    2016-01-01

    During nephrogenesis, POU domain class 3 transcription factor 3 (POU3F3 aka BRN1) is critically involved in development of distinct nephron segments, including the thick ascending limb of the loop of Henle (TAL). Deficiency of POU3F3 in knock-out mice leads to underdevelopment of the TAL, lack of differentiation of TAL cells, and perinatal death due to renal failure. Pou3f3L423P mutant mice, which were established in the Munich ENU Mouse Mutagenesis Project, carry a recessive point mutation in the homeobox domain of POU3F3. Homozygous Pou3f3L423P mutants are viable and fertile. The present study used functional, as well as qualitative and quantitative morphological analyses to characterize the renal phenotype of juvenile (12 days) and aged (60 weeks) homo- and heterozygous Pou3f3L423P mutant mice and age-matched wild-type controls. In both age groups, homozygous mutants vs. control mice displayed significantly smaller kidney volumes, decreased nephron numbers and mean glomerular volumes, smaller TAL volumes, as well as lower volume densities of the TAL in the kidney. No histological or ultrastructural lesions of TAL cells or glomerular cells were observed in homozygous mutant mice. Aged homozygous mutants displayed increased serum urea concentrations and reduced specific urine gravity, but no evidence of glomerular dysfunction. These results confirm the role of POU3F3 in development and function of the TAL and provide new evidence for its involvement in regulation of the nephron number in the kidney. Therefore, Pou3f3L423P mutant mice represent a valuable research model for further analyses of POU3F3 functions, or for nephrological studies examining the role of congenital low nephron numbers. PMID:27420727

  20. Missense Mutation of POU Domain Class 3 Transcription Factor 3 in Pou3f3L423P Mice Causes Reduced Nephron Number and Impaired Development of the Thick Ascending Limb of the Loop of Henle.

    Directory of Open Access Journals (Sweden)

    Alexandra Rieger

    Full Text Available During nephrogenesis, POU domain class 3 transcription factor 3 (POU3F3 aka BRN1 is critically involved in development of distinct nephron segments, including the thick ascending limb of the loop of Henle (TAL. Deficiency of POU3F3 in knock-out mice leads to underdevelopment of the TAL, lack of differentiation of TAL cells, and perinatal death due to renal failure. Pou3f3L423P mutant mice, which were established in the Munich ENU Mouse Mutagenesis Project, carry a recessive point mutation in the homeobox domain of POU3F3. Homozygous Pou3f3L423P mutants are viable and fertile. The present study used functional, as well as qualitative and quantitative morphological analyses to characterize the renal phenotype of juvenile (12 days and aged (60 weeks homo- and heterozygous Pou3f3L423P mutant mice and age-matched wild-type controls. In both age groups, homozygous mutants vs. control mice displayed significantly smaller kidney volumes, decreased nephron numbers and mean glomerular volumes, smaller TAL volumes, as well as lower volume densities of the TAL in the kidney. No histological or ultrastructural lesions of TAL cells or glomerular cells were observed in homozygous mutant mice. Aged homozygous mutants displayed increased serum urea concentrations and reduced specific urine gravity, but no evidence of glomerular dysfunction. These results confirm the role of POU3F3 in development and function of the TAL and provide new evidence for its involvement in regulation of the nephron number in the kidney. Therefore, Pou3f3L423P mutant mice represent a valuable research model for further analyses of POU3F3 functions, or for nephrological studies examining the role of congenital low nephron numbers.

  1. Clinical and mutational features of X-linked agammaglobulinemia in Mexico.

    Science.gov (United States)

    García-García, E; Staines-Boone, A T; Vargas-Hernández, A; González-Serrano, M E; Carrillo-Tapia, E; Mogica-Martínez, D; Berrón-Ruíz, L; Segura-Mendez, N H; Espinosa-Rosales, F J; Yamazaki-Nakashimada, M A; Santos-Argumedo, L; López-Herrera, G

    2016-04-01

    X-linked agammaglobulinemia (XLA) is caused by BTK mutations, patients typically show <2% of peripheral B cells and reduced levels of all immunoglobulins; they suffer from recurrent infections of bacterial origin; however, viral infections, autoimmune-like diseases, and an increased risk of developing gastric cancer are also reported. In this work, we report the BTK mutations and clinical features of 12 patients diagnosed with XLA. Furthermore, a clinical revision is also presented for an additional cohort of previously reported patients with XLA. Four novel mutations were identified, one of these located in the previously reported mutation refractory SH3 domain. Clinical data support previous reports accounting for frequent respiratory, gastrointestinal tract infections and other symptoms such as the occurrence of reactive arthritis in 19.2% of the patients. An equal proportion of patients developed septic arthritis; missense mutations and mutations in SH1, SH2 and PH domains predominated in patients who developed arthritis.

  2. SIFT missense predictions for genomes.

    Science.gov (United States)

    Vaser, Robert; Adusumalli, Swarnaseetha; Leng, Sim Ngak; Sikic, Mile; Ng, Pauline C

    2016-01-01

    The SIFT (sorting intolerant from tolerant) algorithm helps bridge the gap between mutations and phenotypic variations by predicting whether an amino acid substitution is deleterious. SIFT has been used in disease, mutation and genetic studies, and a protocol for its use has been previously published with Nature Protocols. This updated protocol describes SIFT 4G (SIFT for genomes), which is a faster version of SIFT that enables practical computations on reference genomes. Users can get predictions for single-nucleotide variants from their organism of interest using the SIFT 4G annotator with SIFT 4G's precomputed databases. The scope of genomic predictions is expanded, with predictions available for more than 200 organisms. Users can also run the SIFT 4G algorithm themselves. SIFT predictions can be retrieved for 6.7 million variants in 4 min once the database has been downloaded. If precomputed predictions are not available, the SIFT 4G algorithm can compute predictions at a rate of 2.6 s per protein sequence. SIFT 4G is available from http://sift-dna.org/sift4g.

  3. Chronic nonspherocytic hemolytic anemia due to glucose-6-phosphate dehydrogenase deficiency: report of two families with novel mutations causing G6PD Bangkok and G6PD Bangkok Noi.

    Science.gov (United States)

    Tanphaichitr, Voravarn S; Hirono, Akira; Pung-amritt, Parichat; Treesucon, Ajjima; Wanachiwanawin, Wanchai

    2011-07-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common hereditary enzymopathies worldwide. Mostly G6PD deficient cases are asymptomatic though they may have the risk of neonatal jaundice (NNJ) and acute intravascular hemolysis during oxidative stress. Chronic nonspherocytic hemolytic anemia (CNSHA) due to G6PD deficiency is rare. In Thailand, one case was reported 40 years ago and by biochemical study this G6PD was reported to be a new variant G6PD Bangkok. We, herein, report two families with CNSHA due to G6PD deficiency. In the first family, we have been following up the clinical course of the patient with G6PD Bangkok. In addition to chronic hemolysis, he had three acute hemolytic episodes requiring blood transfusions during childhood period. Multiple gallstones were detected at the age of 27. His two daughters who inherited G6PD Bangkok from him and G6PD Vanua Lava from his wife are asymptomatic. Both of them had NNJ and persistent evidences of compensated hemolysis. Molecular analysis revealed a novel missense mutation 825 G→C predicting 275 Lys→Asn causing G6PD Bangkok. In the second family, two male siblings are affected. They had NNJ and several hemolytic episodes which required blood transfusions. On follow-up they have been diagnosed with chronic hemolysis as evidenced by reticulocytosis and indirect hyperbilirubinemia. Molecular analysis revealed combined missense mutations in exons 12 and 13. The first mutation was 1376 G→T predicting 459 Arg→Leu (known as G6PD Canton) and the second one was 1502 T→G predicting 501 Phe→Cys. We designated the resulting novel G6PD variant, G6PD Bangkok Noi.

  4. Gorlin syndrome and desmoplastic medulloblastoma: Report of 3 cases with unfavorable clinical course and novel mutations.

    Science.gov (United States)

    Gururangan, Sridharan; Robinson, Giles; Ellison, David W; Wu, Gang; He, Xuelian; Lu, Q Richard; McLendon, Roger; Grant, Gerald; Driscoll, Timothy; Neuberg, Ronnie

    2015-10-01

    We present three cases of genetically confirmed Gorlin syndrome with desmoplastic medulloblastoma (DMB) in whom tumor recurred despite standard therapy. One patient was found to have a novel germline missense PTCH1 mutation. Molecular analysis of recurrent tumor using fluorescent in situ hybridization (FISH) revealed PTEN and/ or PTCH1 loss in 2 patients. Whole exome sequencing (WES) of tumor in one patient revealed loss of heterozygosity of PTCH1 and a mutation of GNAS gene in its non-coding 3' -untranslated region (UTR) with corresponding decreased protein expression. While one patient died despite high-dose chemotherapy (HDC) plus stem cell rescue (ASCR) and palliative radiotherapy, two patients are currently alive for 18+ and 120+ months respectively following retrieval therapy that did not include irradiation. Infants with DMB and GS should be treated aggressively with chemotherapy at diagnosis to prevent relapse but radiotherapy should be avoided. The use of molecular prognostic markers for DMB should be routinely used to identify the subset of tumors that might have an aggressive course.

  5. Infection-triggered familial or recurrent cases of acute necrotizing encephalopathy caused by mutations in a component of the nuclear pore, RANBP2

    DEFF Research Database (Denmark)

    Neilson, Derek E; Adams, Mark D; Orr, Caitlin M D

    2009-01-01

    a susceptibility locus (ANE1) in a family segregating recurrent ANE as an incompletely penetrant, autosomal-dominant trait. We now report that all affected individuals and obligate carriers in this family are heterozygous for a missense mutation (c.1880C-->T, p.Thr585Met) in the gene encoding the nuclear pore...

  6. Identification of the First De Novo UBIAD1 Gene Mutation Associated with Schnyder Corneal Dystrophy

    Directory of Open Access Journals (Sweden)

    Benjamin R. Lin

    2016-01-01

    Full Text Available Purpose. To report the identification of the first de novo UBIAD1 missense mutation in an individual with Schnyder corneal dystrophy (SCD. Methods. A slit lamp examination was performed on a 47-year-old woman without a family history of corneal disorders. The proband’s parents, two sisters, and son were also examined and genomic DNA from all six individuals was collected. The exons and exon-intron boundaries of UBIAD1 were screened using Sanger sequencing. Identified mutations were screened for in 200 control chromosomes. In silico analysis predicted the impact of identified mutations on protein function and structure. Results. Slit lamp examination of the proband revealed findings consistent with SCD. Corneas of the family members appeared unaffected. Screening of UBIAD1 in the proband identified a novel heterozygous c.308C>T mutation, predicted to encode the missense amino acid substitution p.(Thr103Ile. This mutation was not identified in any of the family members or in 200 control chromosomes and was predicted to be damaging to normal protein function and structure. Conclusions. We present a novel heterozygous de novo missense mutation in UBIAD1, p.(Thr103Ile, identified in a patient with classic clinical features of SCD. This highlights the value of genetic testing in clinical diagnostic settings, even in the absence of a positive family history.

  7. Novel PORCN mutations in focal dermal hypoplasia.

    Science.gov (United States)

    Froyen, G; Govaerts, K; Van Esch, H; Verbeeck, J; Tuomi, M-L; Heikkilä, H; Torniainen, S; Devriendt, K; Fryns, J-P; Marynen, P; Järvelä, I; Ala-Mello, S

    2009-12-01

    Focal dermal hypoplasia (FDH), Goltz or Goltz-Gorlin syndrome, is an X-linked dominant multisystem disorder characterized primarily by involvement of the skin, skeletal system and eyes. We screened for mutations in the PORCN gene in eight patients of Belgian and Finnish origin with firm clinical suspicion of FDH. First, we performed quantitative PCR (qPCR) analysis to define the copy number at this locus. Next, we sequenced the coding regions and flanking intronic sequences of the PORCN gene. Three de novo mutations were identified in our patients with FDH: a 150-kb deletion removing six genes including PORCN, as defined by qPCR and X-array-CGH, and two heterozygous missense mutations; c.992T>G (p.L331R) in exon 11 and c.1094G>A (p.R365Q) in exon 13 of the gene. Both point mutations changed highly conserved amino acids and were not found in 300 control X chromosomes. The three patients in whom mutations were identified all present with characteristic dermal findings together with limb manifestations, which were not seen in our mutation-negative patients. The clinical characteristics of our patients with PORCN mutations were compared with the previously reported mutation-positive cases. In this report, we summarize the literature on PORCN mutations and associated phenotypes.

  8. Science Letters: Screen p53 mutations in hepatocellular carcinoma by FASAY: A novel splicing mutation

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-mo; FU Jing-geng; GE Wang-zhong; ZHU Jiang-yan; WANG Jun-yong; ZHANG Wei; QIAN Wei; HUO Ke-ke

    2007-01-01

    Objective: To establish a routine procedure for the detection of p53 mutations in hepatocellular carcinoma (HCC)surgical resections using the FASAY (functional analysis of separated alleles of p53 on yeast) procedure. Methods: p53 status was analyzed by FASAY and cDNA sequencing in 50 cases of HCC. After the extraction of RNA from the frozen tumor and corresponding normal tissues, reverse transcription RT-PCR was carried out using these samples. The assay can detect mutations of p53mRNA between codons 67 and 347 by the DNA-binding activity of the protein and reveal them as red colonies. Results: Of the 50specimens, 29 (58%) were positive (mutant) by FASAY. Sequencing analysis confirmed that all 29 FASAY positive tumors harbored mutations, and that no mutations were detectable in any FASAY negative tumors. In 29 p53 mutations, 22 mutations were point missense mutation, 5 were deletions and 2 were splicing mutations. A novel splice mutation on splice donor of intron 6was reported, which could produce two different mRNAs, respectively using the nearest upstream and downstream recessive splice donor sites. Conclusion: FASAY is a sensitive method for detecting the various types of p53 mutations in HCC, suggesting that the yeast functional assay for the detection of p53 mutations may be essential for elucidating their clinical significance.

  9. Mutations of ARX are associated with striking pleiotropy and consistent genotype-phenotype correlation.

    Science.gov (United States)

    Kato, Mitsuhiro; Das, Soma; Petras, Kristin; Kitamura, Kunio; Morohashi, Ken-ichirou; Abuelo, Diane N; Barr, Mason; Bonneau, Dominique; Brady, Angela F; Carpenter, Nancy J; Cipero, Karen L; Frisone, Francesco; Fukuda, Takayuki; Guerrini, Renzo; Iida, Eri; Itoh, Masayuki; Lewanda, Amy Feldman; Nanba, Yukiko; Oka, Akira; Proud, Virginia K; Saugier-Veber, Pascale; Schelley, Susan L; Selicorni, Angelo; Shaner, Rachel; Silengo, Margherita; Stewart, Fiona; Sugiyama, Noriyuki; Toyama, Jun; Toutain, Annick; Vargas, Ana Lía; Yanazawa, Masako; Zackai, Elaine H; Dobyns, William B

    2004-02-01

    We recently identified mutations of ARX in nine genotypic males with X-linked lissencephaly with abnormal genitalia (XLAG), and in several female relatives with isolated agenesis of the corpus callosum (ACC). We now report 13 novel and two recurrent mutations of ARX, and one nucleotide change of uncertain significance in 20 genotypic males from 16 families. Most had XLAG, but two had hydranencephaly and abnormal genitalia, and three males from one family had Proud syndrome or ACC with abnormal genitalia. We obtained detailed clinical information on all 29 affected males, including the nine previously reported subjects. Premature termination mutations consisting of large deletions, frameshifts, nonsense mutations, and splice site mutations in exons 1 to 4 caused XLAG or hydranencephaly with abnormal genitalia. Nonconservative missense mutations within the homeobox caused less severe XLAG, while conservative substitution in the homeodomain caused Proud syndrome. A nonconservative missense mutation near the C-terminal aristaless domain caused unusually severe XLAG with microcephaly and mild cerebellar hypoplasia. In addition, several less severe phenotypes without malformations have been reported, including mental retardation with cryptogenic infantile spasms (West syndrome), other seizure types, dystonia or autism, and nonsyndromic mental retardation. The ARX mutations associated with these phenotypes have included polyalanine expansions or duplications, missense mutations, and one deletion of exon 5. Together, the group of phenotypes associated with ARX mutations demonstrates remarkable pleiotropy, but also comprises a nearly continuous series of developmental disorders that begins with hydranencephaly, lissencephaly, and agenesis of the corpus callosum, and ends with a series of overlapping syndromes with apparently normal brain structure.

  10. Two missense mutations, E123Q and K151E, identified in the ERG11 allele of an azole-resistant isolate of Candida kefyr recovered from a stem cell transplant patient for acute myeloid leukemia

    Directory of Open Access Journals (Sweden)

    Célia Couzigou

    2014-07-01

    Full Text Available We report on the first cloning and nucleotide sequencing of an ERG11 allele from a clinical isolate of Candida kefyr cross-resistant to azole antifungals. It was recovered from a stem cell transplant patient, in an oncohematology unit exhibiting unexpected high prevalence of C. kefyr. Two amino acid substitutions were identified: K151E, whose role in fluconazole resistance was already demonstrated in Candida albicans, and E123Q, a new substitution never described so far in azole-resistant Candida yeast.

  11. [Somatic mutations in nuclear and mitochondrial DNA]. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    1992-09-01

    The study is concerned the design of new assays that may detect rare somatic mutations in nuclear and mitochondrial DNA, which may increase upon exposure to mutagens, and thus become a marker of human exposure to such mutagens. Two assays for somatic mutation were presented, one for mitochondrial DNA deletions which was developed by the author, and one for deletions of the ADA gene which resides in the nucleus.

  12. Preliminary Report of Molecular Detection of Retinoblastoma Gene Mutations

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    To develop gene diagnosis for retinoblastoma predisposition, it is necessary to disclose the retinoblastoma gene mutations or deletions in detail. Genomic DNA from tumor and peripheral white blood cells in 33 patients with retinoblastoma was detected with 3.8kb probe derived from 3' end of retinoblastoma gene cDNA. The gene abnormalities, including deletion, partial deletion and rearrangement, were found in 18 patients. Further research will be aimed at microdeletions or mutations for those patients wti...

  13. Somatic mosaicism for a novel PDHA1 mutation in a male with severe pyruvate dehydrogenase complex deficiency

    Directory of Open Access Journals (Sweden)

    Kristin K. Deeb

    2014-01-01

    Full Text Available Pyruvate dehydrogenase complex (PDC deficiencies are mostly due to mutations in the X-linked PDHA1 gene. Males with hemizygous PDHA1 mutations are clinically more severely affected, while those with mosaic PDHA1 mutations may manifest milder phenotypes. We report a patient harboring a novel, mosaic missense PDHA1 mutation, c.523G > A (p.A175T, with a severe clinical presentation of congenital microcephaly, significant brain abnormalities, persistent seizures, profound developmental delay, and failure to thrive. We review published cases of PDHA1 mosaicism.

  14. [Infantile hypophosphatasia caused by a novel compound heterozygous mutation: a case report and pedigree analysis].

    Science.gov (United States)

    Li, Deng-Feng; Lan, Dan; Zhong, Jing-Zi; Dewan, Roma Kajal; Xie, Yan-Shu; Yang, Ying

    2017-05-01

    This article reported the clinical features of one child with infantile hypophosphatasia (HPP) and his pedigree information. The proband was a 5-month-old boy with multiple skeletal dysplasia (koilosternia, bending deformity of both radii, and knock-knee deformity of both knees), feeding difficulty, reduction in body weight, developmental delay, recurrent pneumonia and respiratory failure, and a significant reduction in blood alkaline phosphatase. Among his parents, sister, uncle, and aunt (other family members did not cooperate with us in the examination), his parents and aunt had a slight reduction in alkaline phosphatase and his aunt had scoliosis; there were no other clinical phenotypes or abnormal laboratory testing results. His ALPL gene mutation came from c.228delG mutation in his mother and c.407G>A compound heterozygous mutation in his father. His aunt carried c.228delG mutation. The c.407G>A mutation had been reported as the pathogenic mutation of HPP, and c.228delG mutation was a novel pathogenic mutation. Hypophosphatasia is caused by ALPL gene mutation, and ALPL gene detection is an effective diagnostic method. This study expands the mutation spectrum of ALPL gene and provides a theoretical basis for genetic diagnosis of this disease.

  15. [Analysis of GALNS gene mutation in thirty-eight Chinese patients with mucopolysaccharidosis type IVA].

    Science.gov (United States)

    Ye, Jun; Lei, Hong-lin; Zhang, Hui-wen; Qiu, Wen-juan; Han, Lian-shu; Wang, Yu; Li, Xiao-yan; Gu, Xue-fan

    2013-06-01

    novel missense variants were ruled out by the PCR-restriction fragment length polymorphism analysis and no related mutations were found in 50 normal controls. A splice site mutation IVS9-2A>C had been validated by reverse transcription PCR direct sequencing. The amino acid of mutant position of 10 kinds of missense variants are highly conserved and only p. L454 is moderately conserved position. These missense variants were predicted to cause damage to the structure and function of human GALNS protein possibly according to the PolyPhen-2 tool, so these novel missense variants may be disease-causing mutations. (3) Prenatal diagnosis was provided for 7 families and three fetuses were diagnosed as MPS IVA. The GALNS gene mutation spectrum in Chinese patients with MPS IVA is really different from that in other countries, five kinds of mutation were only found in Chinese patients with MPS IVA. The reports of hot-spot mutation in Chinese patients were also different, and should be analyzed by more data of gene mutation analysis and epidemiological study.

  16. Seven functional classes of Barth syndrome mutation

    Science.gov (United States)

    Whited, Kevin; Baile, Matthew G.; Currier, Pamela; Claypool, Steven M.

    2013-01-01

    Patients with Barth syndrome (BTHS), a rare X-linked disease, suffer from skeletal and cardiomyopathy and bouts of cyclic neutropenia. The causative gene encodes tafazzin, a transacylase, which is the major determinant of the final acyl chain composition of the mitochondrial-specific phospholipid, CL. In addition to numerous frame shift and splice-site mutations, 36 missense mutations have been associated with BTHS. Previously, we established a BTHS-mutant panel in the yeast Saccharomyces cerevisiae that successfully models 18/21 conserved pathogenic missense mutations and defined the loss-of-function mechanism associated with a subset of the mutant tafazzins. Here, we report the biochemical and cell biological characterization of the rest of the yeast BTHS-mutant panel and in so doing identify three additional modes of tafazzin dysfunction. The largest group of mutant tafazzins is catalytically null, two mutants encode hypomorphic alleles, and another two mutants are temperature sensitive. Additionally, we have expanded the defects associated with previously characterized matrix-mislocalized-mutant tafazzins to include the rapid degradation of aggregation-prone polypeptides that correctly localize to the mitochondrial IMS. In sum, our in-depth characterization of the yeast BTHS-mutant panel has identified seven functional classes of BTHS mutation. PMID:23100323

  17. Homomeric and heteromeric interactions between wild-type and mutant phenylalanine hydroxylase subunits: evaluation of two-hybrid approaches for functional analysis of mutations causing hyperphenylalaninemia.

    Science.gov (United States)

    Waters, P J; Scriver, C R; Parniak, M A

    2001-07-01

    Phenylketonuria (PKU) is caused by mutations in the phenylalanine hydroxylase gene (PAH), while mutations in genes encoding the two enzymes (dihydropteridine reductase, DHPR, and pterin-4-alpha-carbinolamine dehydratase, PCD) required for recycling of its cofactor, tetrahydrobiopterin (BH(4)), cause other rarer disease forms of hyperphenylalaninemia. We have applied a yeast two-hybrid method, in which protein--protein interactions are measured by four reporter gene constructs, to the analysis of six PKU-associated PAH missense mutations (F39L, K42I, L48S, I65T, A104D, and R157N). By studying homomeric interactions between mutant PAH subunits, we show that this system is capable of detecting quite subtle aberrations in PAH oligomerization caused by missense mutations and that the observed results generally correlate with the severity of the mutation as determined by other expression systems. The mutant PAH subunits are also shown in this system to be able to interact with wild-type PAH subunits, pointing to an explanation for apparent dominant negative effects previously observed in obligate heterozygotes for PKU mutations. Based on our findings, the applications and limitations of two-hybrid approaches in understanding mechanisms by which PAH missense mutations exert their pathogenic effects are discussed. We have also used this technique to demonstrate homomeric interactions between wild-type DHPR subunits and between wild-type PCD subunits. These data provide a basis for functional studies on HPA-associated mutations affecting these enzymes.

  18. Mutational screening of the RB1 gene in Italian patients with retinoblastoma reveals 11 novel mutations.

    Science.gov (United States)

    Sampieri, Katia; Hadjistilianou, Theodora; Mari, Francesca; Speciale, Caterina; Mencarelli, Maria Antonietta; Cetta, Francesco; Manoukian, Siranoush; Peissel, Bernard; Giachino, Daniela; Pasini, Barbara; Acquaviva, Antonio; Caporossi, Aldo; Frezzotti, Renato; Renieri, Alessandra; Bruttini, Mirella

    2006-01-01

    Retinoblastoma (RB, OMIM#180200) is the most common intraocular tumour in infancy and early childhood. Constituent mutations in the RB1 gene predispose individuals to RB development. We performed a mutational screening of the RB1 gene in Italian patients affected by RB referred to the Medical Genetics of the University of Siena. In 35 unrelated patients, we identified germline RB1 mutations in 6 out of 9 familial cases (66%) and in 7 out of 26 with no family history of RB (27%). Using the single-strand conformational polymorphism (SSCP) technique, 11 novel mutations were detected, including 3 nonsense, 5 frameshift and 4 splice-site mutations. Only two of these mutations (1 splice site and 1 missense) were previously reported. The mutation spectrum reflects the published literature, encompassing predominately nonsense or frameshift and splicing mutations. RB1 germline mutation was detected in 37% of our cases. Gross rearrangements outside the investigated region, altered DNA methylation, or mutations in non-coding regions, may be the cause of disease in the remainder of the patients. Some cases, e.g. a case of incomplete penetrance, or variable expressivity ranging from retinoma to multiple tumours, are discussed in detail. In addition, a case of pre-conception genetic counselling resolved by rescue of banked cordonal blood of the affected deceased child is described.

  19. Novel and recurrent mutations in lamin A/C in patients with Emery-Dreifuss muscular dystrophy.

    Science.gov (United States)

    Brown, C A; Lanning, R W; McKinney, K Q; Salvino, A R; Cherniske, E; Crowe, C A; Darras, B T; Gominak, S; Greenberg, C R; Grosmann, C; Heydemann, P; Mendell, J R; Pober, B R; Sasaki, T; Shapiro, F; Simpson, D A; Suchowersky, O; Spence, J E

    2001-09-01

    Emery-Dreifuss muscular dystrophy (EDMD) is characterized by slowly progressive muscle wasting and weakness; early contractures of the elbows, Achilles tendons, and spine; and cardiomyopathy associated with cardiac conduction defects. Clinically indistinguishable X-linked and autosomal forms of EDMD have been described. Mutations in the STA gene, encoding the nuclear envelope protein emerin, are responsible for X-linked EDMD, while mutations in the LMNA gene encoding lamins A and C by alternative splicing have been found in patients with autosomal dominant, autosomal recessive, and sporadic forms of EDMD. We report mutations in LMNA found in four familial and seven sporadic cases of EDMD, including seven novel mutations. Nine missense mutations and two small in-frame deletions were detected distributed throughout the gene. Most mutations (7/11) were detected within the LMNA exons encoding the central rod domain common to both lamins A/C. All of these missense mutations alter residues in the lamin A/C proteins conserved throughout evolution, implying an essential structural and/or functional role of these residues. One severely affected patient possesed two mutations, one specific to lamin A that may modify the phenotype of this patient. Mutations in LMNA were frequently identified among patients with sporadic and familial forms of EDMD. Further studies are needed to identify the factors modifying disease phenotype among patients harboring mutations within lamin A/C and to determine the effect of various mutations on lamin A/C structure and function.

  20. Novel germline c-MET mutation in a family with hereditary papillary renal carcinoma

    DEFF Research Database (Denmark)

    Wadt, Karin; Gerdes, Anne-Marie; Hansen, Thomas V O;

    2012-01-01

    Hereditary papillary renal carcinoma (HPRC) is a highly penetrant hereditary renal cancer syndrome caused by germline missense mutations in the c-MET proto-oncogene. HPRC is clinically characterized by multiple bilateral papillary renal-cell carcinomas. Here we report a family with a novel missense...... mutation in c-MET. The original pathology report of four primary kidney cancers (1988-1997) revealed renal-cell carcinoma. A revised report described multiple adenomas and papillary renal-cell carcinomas with focal clear cells and a mixture of type 1 and type 2 pattern, emphasizing the importance...... of revised pathology examinations in possible hereditary renal-cell carcinomas especially when described before 1997....

  1. A novel missense mutation of FOXP3 causes immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome in a Chinese child%X连锁多内分泌腺病肠病伴免疫失调综合征一例基因及蛋白表达研究

    Institute of Scientific and Technical Information of China (English)

    安云飞; 赵晓东; 许峰; 杨锡强

    2009-01-01

    Objective To investigate variation of FOXP3 and it's expression in male children presented with severe and early-onset enteropathy, rash with or without insulin-dependent diabetes mellitus (IDDM). Methods Four male children presented with severe and early-onset enteropathy, rash, with or without IDDM were subjected to detection of FOXP3 expression on the PBMC by flow cytometry and FOXP3 gene analysis. The maternal gene analysis was subsequently performed once the variant FOXP3 gene was found. All 11 exons and splice sites within FOXP3 gene were amplified by polymerase chain reaction (PCR) from genomic DNA. Reverse transcription polymerase chain reaction was used to amplify the FOXP3 transcripts. Sequence analysis was performed directly on the bulk PCR products forwardly and reversely. The candidate mutation site was compared with that of 100 healthy controls to exclude polymorphism. Flow cytometry was used to determine FOXP3 expression on CD4~+ CD25~+ T cells and the frequency of Tregs in CD4~+ T cells. Results One of the 4 patients showed a G13128A genetic variation in exon 11, which resulted in a Met370Ile substitution. No sequence variations were found at the same site in any of 100 healthy controls, indicating that the Met370Ile substitution is not a polymorphism but a novel missense mutation. The patient's mother was identified as a carrier for this mutation. There was no reduced frequency of Tregs in the peripheral blood of the patient and FOXP3 protein expression is normal as compared with controls. Conclusion A novel missense mutation of FOXP3 which causes IPEX phenotype was identified in a Chinese child according to immunologic screening and gene sequencing. Infants with early-onset IDDM and persistent diarrhea should be suspected as IPEX, FOXP3 gene analysis will be a reliable diagnostic approach to IPEX.%目的 探讨表现为顽固性腹泻、皮疹以及有或无胰岛素依赖性糖尿病的疑似X连锁多内分泌腺病肠病伴免

  2. Frontotemporal dementia caused by CHMP2B mutations

    DEFF Research Database (Denmark)

    Isaacs, A M; Johannsen, P; Holm, I

    2011-01-01

    CHMP2B mutations are a rare cause of autosomal dominant frontotemporal dementia (FTD). The best studied example is frontotemporal dementia linked to chromosome 3 (FTD-3) which occurs in a large Danish family, with a further CHMP2B mutation identified in an unrelated Belgian familial FTD patient....... These mutations lead to C-terminal truncations of the CHMP2B protein and we will review recent advances in our understanding of the molecular effects of these mutant truncated proteins on vesicular fusion events within the endosome-lysosome and autophagy degradation pathways. We will also review the clinical...... features of FTD caused by CHMP2B truncation mutations as well as new brain imaging and neuropathological findings. Finally, we collate the current data on CHMP2B missense mutations, which have been reported in FTD and motor neuron disease....

  3. Missense dopamine transporter mutations associate with adult parkinsonism and ADHD

    DEFF Research Database (Denmark)

    Hansen, Freja H; Skjørringe, Tina; Yasmeen, Saiqa

    2014-01-01

    Parkinsonism and attention deficit hyperactivity disorder (ADHD) are widespread brain disorders that involve disturbances of dopaminergic signaling. The sodium-coupled dopamine transporter (DAT) controls dopamine homeostasis, but its contribution to disease remains poorly understood. Here, we......-deoxy-glucose-PET/MRI (FDG-PET/MRI) scan, the patient suffered from progressive dopaminergic neurodegeneration. In heterologous cells, both DAT variants exhibited markedly reduced dopamine uptake capacity but preserved membrane targeting, consistent with impaired catalytic activity. Computational simulations and uptake...... experiments suggested that the disrupted function of the DAT-Asp421Asn mutant is the result of compromised sodium binding, in agreement with Asp421 coordinating sodium at the second sodium site. For DAT-Asp421Asn, substrate efflux experiments revealed a constitutive, anomalous efflux of dopamine...

  4. Two novel missense mutations in bovine ATGL gene and their ...

    African Journals Online (AJOL)

    user

    2011-03-21

    Mar 21, 2011 ... exon 7 bringing T320S, respectively. The 3289 G>C .... pyrosequencing vacuum prep tool. The secondary ... phism level at 3514 A>T locus, while QC and LX belong ..... Technological Projects of New GMO Breeding (No.

  5. Prenatal Diagnosis in a Family of TNFRSF11A (RANK Gene Mutation Detection: A Case Report

    Directory of Open Access Journals (Sweden)

    Mutlu Karkucak

    2014-08-01

    Full Text Available Autosomal recessive osteoporosis (ARO is a severe disease causing death usually at infancy or childhood. RANKL coded by TNFSF11 gene and RANK coded by TNFRSF11A gene are important proteins for osteoclast maturation and it is indicated that mutation on these genes plays an important role for ARO development. It is reported in this article that c.508 A→G homozygote mutation (pArg170Gly is observed in TNFRSF11A gene of 2 children of consanguineous couple. Mutation analysis performed on CVS material during the next pregnancy revealed heterozygous mutation in the fetus. The pregnancy was continued to term and a healthy boy was delivered. Prenatal mutation analysis is important for diseases with known mutations to relieve parental anxiety and provide genetic counselling for the family.

  6. Mutations in planar cell polarity gene SCRIB are associated with spina bifida.

    Directory of Open Access Journals (Sweden)

    Yunping Lei

    Full Text Available Neural tube defects (NTDs (OMIM #182940 including anencephaly, spina bifida and craniorachischisis, are severe congenital malformations that affect 0.5-1 in 1,000 live births in the United States, with varying prevalence around the world. Mutations in planar cell polarity (PCP genes are believed to cause a variety of NTDs in both mice and humans. SCRIB is a PCP-associated gene. Mice that are homozygous for the Scrib p.I285K and circletail (Crc mutations, present with the most severe form of NTDs, namely craniorachischisis. A recent study reported that mutations in SCRIB were associated with craniorachischisis in humans, but whether SCRIB mutations contribute to increased spina bifida risk is still unknown. We sequenced the SCRIB gene in 192 infants with spina bifida and 190 healthy controls. Among the spina bifida patients, we identified five novel missense mutations that were predicted-to-be-deleterious by the PolyPhen software. Of these five mutations, three of them (p.P1043L, p.P1332L, p.L1520R significantly affected the subcellular localization of SCRIB. In addition, we demonstrated that the craniorachischisis mouse line-90 mutation I285K, also affected SCRIB subcellular localization. In contrast, only one novel missense mutation (p.A1257T was detected in control samples, and it was predicted to be benign. This study demonstrated that rare deleterious mutations of SCRIB may contribute to the multifactorial risk for human spina bifida.

  7. NRAS and BRAF mutation frequency in primary oral mucosal melanoma.

    Science.gov (United States)

    Buery, Rosario Rivera; Siar, Chong Huat; Katase, Naoki; Gunduz, Mehmet; Lefeuvre, Mathieu; Fujii, Masae; Inoue, Masahisa; Setsu, Kojun; Nagatsuka, Hitoshi

    2011-10-01

    Oral mucosal melanoma (OMM) is a fatal sarcoma of unknown etiology. Histological morphology and genetic events are distinct from those of its cutaneous counterpart. Mutation and up-regulation of c-kit has been identified in OMM which may activate downstream molecules such as RAS and RAF. These molecules are involved in the mitogen-activated protein kinase (MAPK) pathway leading to tremendous cell proliferation and survival. NRAS and BRAF mutation and protein expression have been studied in other melanoma subtypes. The purpose of this study was to determine RAS protein expression and NRAS and BRAF mutation in 18 primary OMM cases using immunohistochemistry and mutation analysis. Results showed that RAS is intensely expressed in both in situ and invasive OMMs. However, NRAS mutation was only observed in 2/15 polymerase chain reaction (PCR) amplified cases both of which were silent mutations. On the other hand, BRAF missense mutations were observed only in 1/15 cases with PCR amplification. NRAS and BRAF mutations were independent from previously reported c-kit mutations. The classical V600E BRAF mutation was not found; instead a novel V600L was observed suggesting that the oncogenic event in OMM is different from that in skin melanoma. The low frequency of NRAS and BRAF mutations indicate that these genes are not common, but probable events in OMM pathogenesis, most likely independent of c-kit mutation.

  8. Mitchell-Riley Syndrome: A Novel Mutation in RFX6 Gene

    Directory of Open Access Journals (Sweden)

    Marta Zegre Amorim

    2015-01-01

    Full Text Available A novel RFX6 homozygous missense mutation was identified in an infant with Mitchell-Riley syndrome. The most common features of Mitchell-Riley syndrome were present, including severe neonatal diabetes associated with annular pancreas, intestinal malrotation, gallbladder agenesis, cholestatic disease, chronic diarrhea, and severe intrauterine growth restriction. Perijejunal tissue similar to pancreatic tissue was found in the submucosa, a finding that has not been previously reported in this syndrome. This case associating RFX6 mutation with structural and functional pancreatic abnormalities reinforces the RFX6 gene role in pancreas development and β-cell function, adding information to the existent mutation databases.

  9. Rare ATAD5 missense variants in breast and ovarian cancer patients.

    Science.gov (United States)

    Maleva Kostovska, Ivana; Wang, Jing; Bogdanova, Natalia; Schürmann, Peter; Bhuju, Sabin; Geffers, Robert; Dürst, Matthias; Liebrich, Clemens; Klapdor, Rüdiger; Christiansen, Hans; Park-Simon, Tjoung-Won; Hillemanns, Peter; Plaseska-Karanfilska, Dijana; Dörk, Thilo

    2016-06-28

    ATAD5/ELG1 is a protein crucially involved in replication and maintenance of genome stability. ATAD5 has recently been identified as a genomic risk locus for both breast and ovarian cancer through genome-wide association studies. We aimed to investigate the spectrum of coding ATAD5 germ-line mutations in hospital-based series of patients with triple-negative breast cancer or serous ovarian cancer compared with healthy controls. The ATAD5 coding and adjacent splice site regions were analyzed by targeted next-generation sequencing of DNA samples from 273 cancer patients, including 114 patients with triple-negative breast cancer and 159 patients with serous epithelial ovarian cancer, and from 276 healthy females. Among 42 different variants identified, twenty-two were rare missense substitutions, of which 14 were classified as pathogenic by at least one in silico prediction tool. Three of four novel missense substitutions (p.S354I, p.H974R and p.K1466N) were predicted to be pathogenic and were all identified in ovarian cancer patients. Overall, rare missense variants with predicted pathogenicity tended to be enriched in ovarian cancer patients (14/159) versus controls (11/276) (p = 0.05, 2df). While truncating germ-line variants in ATAD5 were not detected, it remains possible that several rare missense variants contribute to genetic susceptibility toward epithelial ovarian carcinomas.

  10. Heterozygous Reelin Mutations Cause Autosomal-Dominant Lateral Temporal Epilepsy

    Science.gov (United States)

    Dazzo, Emanuela; Fanciulli, Manuela; Serioli, Elena; Minervini, Giovanni; Pulitano, Patrizia; Binelli, Simona; Di Bonaventura, Carlo; Luisi, Concetta; Pasini, Elena; Striano, Salvatore; Striano, Pasquale; Coppola, Giangennaro; Chiavegato, Angela; Radovic, Slobodanka; Spadotto, Alessandro; Uzzau, Sergio; La Neve, Angela; Giallonardo, Anna Teresa; Mecarelli, Oriano; Tosatto, Silvio C.E.; Ottman, Ruth; Michelucci, Roberto; Nobile, Carlo

    2015-01-01

    Autosomal-dominant lateral temporal epilepsy (ADLTE) is a genetic epilepsy syndrome clinically characterized by focal seizures with prominent auditory symptoms. ADLTE is genetically heterogeneous, and mutations in LGI1 account for fewer than 50% of affected families. Here, we report the identification of causal mutations in reelin (RELN) in seven ADLTE-affected families without LGI1 mutations. We initially investigated 13 ADLTE-affected families by performing SNP-array linkage analysis and whole-exome sequencing and identified three heterozygous missense mutations co-segregating with the syndrome. Subsequent analysis of 15 small ADLTE-affected families revealed four additional missense mutations. 3D modeling predicted that all mutations have structural effects on protein-domain folding. Overall, RELN mutations occurred in 7/40 (17.5%) ADLTE-affected families. RELN encodes a secreted protein, Reelin, which has important functions in both the developing and adult brain and is also found in the blood serum. We show that ADLTE-related mutations significantly decrease serum levels of Reelin, suggesting an inhibitory effect of mutations on protein secretion. We also show that Reelin and LGI1 co-localize in a subset of rat brain neurons, supporting an involvement of both proteins in a common molecular pathway underlying ADLTE. Homozygous RELN mutations are known to cause lissencephaly with cerebellar hypoplasia. Our findings extend the spectrum of neurological disorders associated with RELN mutations and establish a link between RELN and LGI1, which play key regulatory roles in both the developing and adult brain. PMID:26046367

  11. Mutations in ZBTB20 cause Primrose syndrome.

    Science.gov (United States)

    Cordeddu, Viviana; Redeker, Bert; Stellacci, Emilia; Jongejan, Aldo; Fragale, Alessandra; Bradley, Ted E J; Anselmi, Massimiliano; Ciolfi, Andrea; Cecchetti, Serena; Muto, Valentina; Bernardini, Laura; Azage, Meron; Carvalho, Daniel R; Espay, Alberto J; Male, Alison; Molin, Anna-Maja; Posmyk, Renata; Battisti, Carla; Casertano, Alberto; Melis, Daniela; van Kampen, Antoine; Baas, Frank; Mannens, Marcel M; Bocchinfuso, Gianfranco; Stella, Lorenzo; Tartaglia, Marco; Hennekam, Raoul C

    2014-08-01

    Primrose syndrome and 3q13.31 microdeletion syndrome are clinically related disorders characterized by tall stature, macrocephaly, intellectual disability, disturbed behavior and unusual facial features, with diabetes, deafness, progressive muscle wasting and ectopic calcifications specifically occurring in the former. We report that missense mutations in ZBTB20, residing within the 3q13.31 microdeletion syndrome critical region, underlie Primrose syndrome. This finding establishes a genetic link between these disorders and delineates the impact of ZBTB20 dysregulation on development, growth and metabolism.

  12. Two novel AGXT mutations identified in primary hyperoxaluria type-1 and distinct morphological and structural difference in kidney stones

    Science.gov (United States)

    Wang, Cui; Lu, Jingru; Lang, Yanhua; Liu, Ting; Wang, Xiaoling; Zhao, Xiangzhong; Shao, Leping

    2016-01-01

    Primary hyperoxaluria type 1 (PH1) is a rare genetic disease characterized by excessive oxalate accumulation in plasma and urine, resulting in various phenotypes because of allelic and clinical heterogeneity. This study aimed to detect disease-associated genetic mutations in three PH1 patients in a Chinese family. All AGXT exons and 3 common polymorphisms which might synergistically interact with mutations, including P11L, I340 M and IVSI+74 bp were analyzed by direct sequencing in all family members. It demonstrated that in each of three patients, a previously reported nonsense mutation p.R333* was in cis with a novel missense mutation p.M49L in the minor allele characterized by the polymorphism of 74-bp duplication in intron 1, while the other novel missense mutation p.N72I was in trans with both p.R333* and P.M49L in the major allele. Kidney stones from two sibling patients were also observed though stereomicroscopic examination and scanning electron microscopy. Distinct morphological and inner-structure differences in calculi were noticed, suggesting clinical heterozygosity of PH1 to a certain extent. In brief, two novel missense mutations were identified probably in association with PH1, a finding which should provide an accurate tool for prenatal diagnosis, genetic counseling and screening for potential presymptomatic individuals. PMID:27644547

  13. Late-onset episodic ataxia type 2 associated with a novel loss-of-function mutation in the CACNA1A gene.

    Science.gov (United States)

    Cuenca-León, Ester; Banchs, Isabel; Serra, Selma A; Latorre, Pilar; Fernàndez-Castillo, Noèlia; Corominas, Roser; Valverde, Miguel A; Volpini, Víctor; Fernández-Fernández, José M; Macaya, Alfons; Cormand, Bru

    2009-05-15

    We report a patient with typical features of episodic ataxia type 2 (EA2) but with onset in the sixth decade and associated interictal hand dystonia. He was found to bear the novel heterozygous missense mutation p.Gly638Asp (c.1913G>A) in the CACNA1A gene. Functional analysis of the mutation on P/Q channels expressed in HEK 293 cells revealed a reduction of Ca(2+) current densities, a left-shift in the apparent reversal potential, the slowing of inactivation kinetics and the increase in the rate of current recovery from inactivation. These results are consistent with a decrease in Ca(2+) permeability through mutant P/Q channels. To our knowledge, this is just the second patient with late onset EA2 linked to a CACNA1A mutation and the first to carry a loss-of-function missense mutation.

  14. Frameshift mutation in the PTCH2 gene can cause nevoid basal cell carcinoma syndrome.

    Science.gov (United States)

    Fujii, Katsunori; Ohashi, Hirofumi; Suzuki, Maiko; Hatsuse, Hiromi; Shiohama, Tadashi; Uchikawa, Hideki; Miyashita, Toshiyuki

    2013-12-01

    Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental defects and tumorigenesis. The gene responsible for NBCCS is PTCH1, encoding a receptor for the secreted protein, sonic hedgehog. Recently, a Chinese family with NBCCS carrying a missense mutation in PTCH2, a close homolog of PTCH1, was reported. However, the pathological significance of missense mutations should be discussed cautiously. Here, we report a 13-year-old girl diagnosed with NBCCS based on multiple keratocystic odontogenic tumors and rib anomalies carrying a frameshift mutation in the PTCH2 gene (c.1172_1173delCT). Considering the deleterious nature of the frameshift mutation, our study further confirmed a causative role for the PTCH2 mutation in NBCCS. The absence of typical phenotypes in this case such as palmar/plantar pits, macrocephaly, falx calcification, hypertelorism and coarse face, together with previously reported cases, suggested that individuals with NBCCS carrying a PTCH2 mutation may have a milder phenotype than those with a PTCH1 mutation.

  15. Mutation analysis of mitogen activated protein kinase 1 gene in Indian cases of 46,XY disorder of sex development

    Directory of Open Access Journals (Sweden)

    Dhanjit Kumar Das

    2013-01-01

    Full Text Available Background: Determination of sex is the result of cascade of molecular events that cause undifferentiated bipotential gonad to develop as a testis or an ovary. A series of genes such as SRY, steroidogenic factor-1 (SF1, AR, SRD5 α, Desert hedgehog (DHH etc., have been reported to have a significant role in development of sex in the fetus and secondary sexual characteristics at the time of puberty. Recently, mitogen activated protein kinase kinase kinase 1 (MAP3K1 gene was found to be associated with 46, XY disorders of sex development (DSD. Aim: The present study is focused to identify mutations in MAP3K1 gene in the cohort of 10 Indian patients with 46,XY DSD including one family with two affected sisters. These patients were already screened for SRY, SF1 and DHH gene, but no mutation was observed in any of these genes. Materials and Methods: The entire coding regions of MAP3K1 were amplified and sequenced using the gene specific primers. Results and Discussions: Sequence analysis of MAP3K1 gene has revealed four variants including one missense, two silent and one deletion mutation. The missense mutation p.D806N was observed in four patients with hypospadias. Two patients showed the presence of silent mutation p.Q1028Q present in exon 14. Another silent mutation p.T428T was observed in a patient with gonadal dysgenesis. We have also observed one deletion mutation p. 942insT present in two patients. The pathogenicity of the missense mutation p.D806N was carried out using in-silico approach. Sequence homology analysis has revealed that the aspartate at 806 was found to be well-conserved across species, indicated the importance of this residue. The score for polyphen analysis of this mutation was found to be 0.999 indicating to be pathogenic mutation. Since, p.D806N mutation was found to be important residue; it might contribute to sexual development. We have reported the presence of mutations/polymorphism in MAP3K1 gene. All the mutations were

  16. Different attenuated phenotypes of GM2 gangliosidosis variant B in Japanese patients with HEXA mutations at codon 499, and five novel mutations responsible for infantile acute form.

    Science.gov (United States)

    Tanaka, Akemi; Hoang, Lan Thi Ngcok; Nishi, Yasuaki; Maniwa, Satoshi; Oka, Makio; Yamano, Tsunekazu

    2003-01-01

    Eight mutations of the alpha subunit of beta-hexosaminidase A gene ( HEXA) were identified in eight patients with GM2 gangliosidosis variant B. They were five missense mutations, two splice-site mutations, and one two-base deletion. Five of them, R252L (CGT-->CTT), N295S (AAT-->AAC), W420C (TGG-->TGT), IVS 13, +2A-->C, and del 265-266AC (exon 2), were novel mutations responsible for infantile acute form of GM2 gangliosidosis. Two missense mutations, R499H and R499C, were found in one allele of two patients with attenuated phenotypes. The patient with R499C showed a late infantile form, and the other patient with R499H showed a juvenile form. These two mutations have been reported previously in the patients of other ethnic groups, and they have been known to cause attenuated phenotypes. The milder phenotypes of GM2 gangliosidosis variant B, different from the infantile acute form, have not been reported so far in Japan, and this is the first report of Japanese patients with attenuated phenotypes and their molecular analysis.

  17. Clinical features and MUT gene mutation spectrum in Chinese patients with isolated methylmalonic acidemia: identification of ten novel allelic variants.

    Science.gov (United States)

    Han, Lian-Shu; Huang, Zhuo; Han, Feng; Ye, Jun; Qiu, Wen-Juan; Zhang, Hui-Wen; Wang, Yu; Gong, Zhu-Wen; Gu, Xue-Fan

    2015-11-01

    This study aims to study MUT gene mutation spectrum in Chinese patients with isolated methylmalonic academia (MMA) and their clinical features for the potential genotype-phenotype correlation. Forty-three patients were diagnosed with isolated MMA by elevated blood propionylcarnitine, propionylcarnitine to acetylcarnitine ratio, and urine methylmalonate without hyperhomocysteinemia. The MUT gene was amplified by polymerase chain reaction and directly sequenced. Those patients with at least one variant allele were included. The novel missense mutations were assessed by bioinformatic analysis and screened against alleles sequenced from 50 control participants. Among the 43 patients, 38 had typical clinical presentations, and the majority (30/38) experienced earlyonset MMA. Eight patients died and seven were lost to follow-up. Twenty patients had poor outcomes and eight showed normal development. The 43 identified MUT gene mutations had at least one variant allele, whereas 35 had two mutant alleles. Of the 33 mutations reported before, eight recurrent mutations were identified in 32 patients, and c.729_730insTT (p.D244Lfs*39) was the most common (12/78) in the mutant alleles. Of the 10 novel mutations, six were missense mutations and four were premature termination codon mutations. The six novel missense mutations seemed to be pathogenic. A total of 10 novel MUT mutations were detected in the Chinese population. c.729_730insTT (p.D244Lfs*39) was the most frequent mutation. A genotype-phenotype correlation could not be found, but the genotypic characterization indicated the need of genetic counseling for MMA patients and early prenatal diagnoses for high-risk families.

  18. Mutations of FUS gene in sporadic amyotrophic lateral sclerosis.

    Science.gov (United States)

    Corrado, Lucia; Del Bo, Roberto; Castellotti, Barbara; Ratti, Antonia; Cereda, Cristina; Penco, Silvana; Sorarù, Gianni; Carlomagno, Yari; Ghezzi, Serena; Pensato, Viviana; Colombrita, Claudia; Gagliardi, Stella; Cozzi, Lorena; Orsetti, Valeria; Mancuso, Michelangelo; Siciliano, Gabriele; Mazzini, Letizia; Comi, Giacomo Pietro; Gellera, Cinzia; Ceroni, Mauro; D'Alfonso, Sandra; Silani, Vincenzo

    2010-03-01

    Mutations in the FUS gene have recently been discovered to be a major cause of familial amyotrophic lateral sclerosis (FALS). To determine the identity and frequency of FUS gene mutations in a large cohort of Italian patients enriched in sporadic cases (SALS). Exons 5, 6, 14 and 15 of the FUS gene were screened for mutations in 1009 patients (45 FALS and 964 SALS). The genetic analysis was extended to the entire coding sequence of FUS in all the FALS and 293 of the SALS patients. Seven missense mutations (p.G191S, p.R216C, p.G225V, p.G230C, p.R234C, p.G507D and p.R521C) were identified in nine patients (seven SALS and two FALS), and none in 500 healthy Italian controls. All mutations are novel except for the p.R521C mutation identified in one SALS and one FALS case. Both patients showed a similar unusual presentation, with proximal, mostly symmetrical, upper limb weakness, with neck and axial involvement. With the exception of p.G507D and p.R521C, the mutations identified in SALS patients are all localised in the glycine-rich region encoded by exon 6. In addition, eight different in-frame deletions in two polyglycine motifs were detected, the frequency of which was not significantly different in patients and controls. The results show that FUS missense mutations are present in 0.7% of Italian SALS cases, and confirm the previous mutational frequency reported in FALS (4.4%). An unusual proximal and axial clinical presentation seems to be associated with the presence of the p.R521C mutation.

  19. Genetic and bioinformatics analysis of four novel GCK missense variants detected in Caucasian families with GCK-MODY phenotype.

    Science.gov (United States)

    Costantini, S; Malerba, G; Contreas, G; Corradi, M; Marin Vargas, S P; Giorgetti, A; Maffeis, C

    2015-05-01

    Heterozygous loss-of-function mutations in the glucokinase (GCK) gene cause maturity-onset diabetes of the young (MODY) subtype GCK (GCK-MODY/MODY2). GCK sequencing revealed 16 distinct mutations (13 missense, 1 nonsense, 1 splice site, and 1 frameshift-deletion) co-segregating with hyperglycaemia in 23 GCK-MODY families. Four missense substitutions (c.718A>G/p.Asn240Asp, c.757G>T/p.Val253Phe, c.872A>C/p.Lys291Thr, and c.1151C>T/p.Ala384Val) were novel and a founder effect for the nonsense mutation (c.76C>T/p.Gln26*) was supposed. We tested whether an accurate bioinformatics approach could strengthen family-genetic evidence for missense variant pathogenicity in routine diagnostics, where wet-lab functional assays are generally unviable. In silico analyses of the novel missense variants, including orthologous sequence conservation, amino acid substitution (AAS)-pathogenicity predictors, structural modeling and splicing predictors, suggested that the AASs and/or the underlying nucleotide changes are likely to be pathogenic. This study shows how a careful bioinformatics analysis could provide effective suggestions to help molecular-genetic diagnosis in absence of wet-lab validations.

  20. A cancer-predisposing "hot spot" mutation of the fumarase gene creates a dominant negative protein.

    Science.gov (United States)

    Lorenzato, Annalisa; Olivero, Martina; Perro, Mario; Brière, Jean Jacques; Rustin, Pierre; Di Renzo, Maria Flavia

    2008-02-15

    The Fumarase (Fumarate Hydratase, FH) is a tumor suppressor gene whose germline heterozygous mutations predispose to hereditary leiomyomatosis and renal cell cancer (HLRCC). The FH gene encodes an enzyme of the Krebs cycle, functioning as a homotetramer and catalyzing the hydration of fumarate to malate. Among the numerous FH mutations reported so far, the R190H missense mutation is the most frequent in HLRCC patients. Here we show the functional analyses of the R190H, in comparison to the better characterized E319Q mutation. We first expressed wild-type and mutated proteins in FH deficient human skin fibroblasts, using lentiviral vectors. The wild-type transgene was able to restore the FH enzymatic activity in cells, while the R190H- and E319Q-FH were not. More interestingly, when the same transgenes were expressed in normal, FH-proficient cells, only the R190H-FH reduced the endogenous FH enzymatic activity. By enforcing the expression of equal amount of wild-type and R190H-FH in the same cell, we showed that the mutated FH protein directly inhibited enzymatic activity by nearly abrogating the FH homotetramer formation. These data demonstrate the dominant negative effect of the R190H missense mutation in the FH gene and suggest that the FH tumor-suppressing activity might be impaired in cells carrying a heterozygous mutation. (c) 2007 Wiley-Liss, Inc.

  1. BRCA1 and BRCA2 Gene Mutations Screening In Sporadic Breast Cancer Patients In Kazakhstan.

    Directory of Open Access Journals (Sweden)

    Ainur R. Akilzhanova

    2013-05-01

    Full Text Available Background: A large number of distinct mutations in the BRCA1 and BRCA2 genes have been reported worldwide, but little is known regarding the role of these inherited susceptibility genes in breast cancer risk among Kazakhstan women. Aim: To evaluate the role of BRCA1/2 mutations in Kazakhstan women presenting with sporadic breast cancer. Methods: We investigated the distribution and nature of polymorphisms in BRCA1 and BRCA2 entire coding regions in 156 Kazakhstan sporadic breast cancer cases and 112 age-matched controls using automatic direct sequencing. Results: We identified 22 distinct variants, including 16 missense mutations and 6 polymorphisms in BRCA1/2 genes. In BRCA1, 9 missense mutations and 3 synonymous polymorphisms were observed. In BRCA2, 7 missense mutations and 3 polymorphisms were detected. There was a higher prevalence of observed mutations in Caucasian breast cancer cases compared to Asian cases (p<0.05; higher frequencies of sequence variants were observed in Asian controls. No recurrent or founder mutations were observed in BRCA1/2 genes. There were no statistically significant differences in age at diagnosis, tumor histology, size of tumor, and lymph node involvement between women with breast cancer with or without the BRCA sequence alterations. Conclusions: Considering the majority of breast cancer cases are sporadic, the present study will be helpful in the evaluation of the need for the genetic screening of BRCA1/2 mutations and reliable genetic counseling for Kazakhstan sporadic breast cancer patients. Evaluation of common polymorphisms and mutations and breast cancer risk in families with genetic predisposition to breast cancer is ongoing in another current investigation. 

  2. A young boy with elevated aminotransferases in physical examination -Two novel missense mutations associated with Wilson's disease were found%男性幼儿体检发现转氨酶升高--发现肝豆状核变性两处新的错义突变

    Institute of Scientific and Technical Information of China (English)

    朱渝; 邓思燕; 万朝敏

    2015-01-01

    1例3岁男性患儿因体检发现肝功能异常5个月入院。患儿无厌食、纳差、黄疸等症状,生长发育正常,肝脾无肿大,实验室检查常规筛查铜蓝蛋白水平(35 mg/L)明显降低,其余嗜肝病毒及巨细胞病毒、EB病毒均为阴性。肌酶正常,血糖、血氨及代谢筛查正常,自身免疫肝病抗体阴性。进一步行眼科检查示K-F环阴性,24 h尿铜水平0.56μmol/L(正常)。对患儿、患儿父母及其妹妹进行ATP7B基因检测,明确患儿和其妹妹具有两处新发现错义突变,为Exon7杂合突变c.2075T>C, p.L692P和Exon13杂合突变c.3044T>C, p.L1015P,各来自父母双方,符合复合杂合突变,基因诊断肝豆状核变性(Wilson)病成立。患儿及其妹妹确诊Wilson病后被嘱低铜饮食,患儿给予青霉胺驱铜治疗及锌剂拮抗铜吸收,其妹妹因尚无临床症状,故给予锌剂治疗。患儿经上述治疗3个月后复查肝功能完全正常。%A 3-year-old boy had abnormal liver function, which was found in physical examination, for 5 months before admission. He had no symptoms such as anorexia, poor appetite, and jaundice, had normal growth and development, and showed no hepatosplenomegaly. Laboratory examination revealed signiifcantly reduced ceruloplasmin (35 mg/L), as well as negative hepatotropic virus, cytomegalovirus, and Epstein-Barr virus. There were normal muscle enzymes, blood glucose, and blood ammonia and negative liver-speciifc autoantibodies. The boy had negative K-F ring and normal 24-hour urine copper (0.56 μmol/L). The ATP7B gene testing for the boy, his sister, and their parents detected two novel missense mutations in the boy and his sister, i.e., compound heterozygous mutations in exon 7 (c.2075T>C, p.L692P) and exon 13 (c.3044T>C, p.L1015P), which were inherited from their father and mother, respectively. Wilson's disease was conifrmed by genetic diagnosis in the boy and his sister. The boy and his

  3. Carpenter syndrome: extended RAB23 mutation spectrum and analysis of nonsense-mediated mRNA decay.

    Science.gov (United States)

    Jenkins, Dagan; Baynam, Gareth; De Catte, Luc; Elcioglu, Nursel; Gabbett, Michael T; Hudgins, Louanne; Hurst, Jane A; Jehee, Fernanda Sarquis; Oley, Christine; Wilkie, Andrew O M

    2011-04-01

    Carpenter syndrome, a rare autosomal recessive disorder characterized by a combination of craniosynostosis, polysyndactyly, obesity, and other congenital malformations, is caused by mutations in RAB23, encoding a member of the Rab-family of small GTPases. In 15 out of 16 families previously reported, the disease was caused by homozygosity for truncating mutations, and currently only a single missense mutation has been identified in a compound heterozygote. Here, we describe a further 8 independent families comprising 10 affected individuals with Carpenter syndrome, who were positive for mutations in RAB23. We report the first homozygous missense mutation and in-frame deletion, highlighting key residues for RAB23 function, as well as the first splice-site mutation. Multi-suture craniosynostosis and polysyndactyly have been present in all patients described to date, and abnormal external genitalia have been universal in boys. High birth weight was not evident in the current group of patients, but further evidence for laterality defects is reported. No genotype-phenotype correlations are apparent. We provide experimental evidence that transcripts encoding truncating mutations are subject to nonsense-mediated decay, and that this plays an important role in the pathogenesis of many RAB23 mutations. These observations refine the phenotypic spectrum of Carpenter syndrome and offer new insights into molecular pathogenesis.

  4. FGFR3 mutations and the skin: report of a patient with a FGFR3 gene mutation, acanthosis nigricans, hypochondroplasia and hyperinsulinemia and review of the literature

    DEFF Research Database (Denmark)

    Blomberg, M; Jeppesen, E M; Skovby, F

    2010-01-01

    developed acanthosis nigricans. The report of a K650Q mutation in the FGFR3 gene in a similar case prompted us to conduct a point mutation analysis. The K650Q mutation was confirmed, but in contrast to the previous case, we additionally report findings of hyperinsulinemia. In the recent literature...... keratoses and epidermal nevi, but also other benign skin tumors and a single case of a squamous cell carcinoma. In addition, an overview of the FGFR3 point mutations in relation to each cutaneous element is given. Based on the current knowledge, it seems likely that these cutaneous lesions have a common......Fibroblast growth factor receptor 3 (FGFR3) gene mutations in the germline are well-known causes of skeletal syndromes. Somatic FGFR3 mutations have been found in malignant neoplasms and more recently in several cutaneous elements. We present a 14-year-old girl with mild hypochondroplasia who...

  5. Frameshift mutation hotspot identified in Smith-Magenis syndrome: case report and review of literature.

    Science.gov (United States)

    Truong, Hoa T; Dudding, Tracy; Blanchard, Christopher L; Elsea, Sarah H

    2010-10-08

    Smith-Magenis syndrome (SMS) is a complex syndrome involving intellectual disabilities, sleep disturbance, behavioural problems, and a variety of craniofacial, skeletal, and visceral anomalies. While the majority of SMS cases harbor an ~3.5 Mb common deletion on 17p11.2 that encompasses the retinoic acid induced-1 (RAI1) gene, some patients carry small intragenic deletions or point mutations in RAI1. We present data on two cases of Smith-Magenis syndrome with mutation of RAI1. Both cases are phenotypically consistent with SMS and RAI1 mutation but also have other anomalies not previously reported in SMS, including spontaneous pneumothoraces. These cases also illustrate variability in the SMS phenotype not previously shown for RAI1 mutation cases, including hearing loss, absence of self-abusive behaviours, and mild global delays. Sequencing of RAI1 revealed mutation of the same heptameric C-tract (CCCCCCC) in exon 3 in both cases (c.3103delC one case and and c.3103insC in the other), resulting in frameshift mutations. Of the seven reported frameshift mutations occurring in poly C-tracts in RAI1, four cases (~57%) occur at this heptameric C-tract. Collectively, these results indicate that this heptameric C-tract is a preferential hotspot for single nucleotide insertion/deletions (SNindels) and therefore, should be considered a primary target for analysis in patients suspected for mutations in RAI1. We expect that as more patients are sequenced for mutations in RAI1, the incidence of frameshift mutations in this hotspot will become more evident.

  6. Frameshift mutation hotspot identified in Smith-Magenis syndrome: case report and review of literature

    Directory of Open Access Journals (Sweden)

    Dudding Tracy

    2010-10-01

    Full Text Available Abstract Smith-Magenis syndrome (SMS is a complex syndrome involving intellectual disabilities, sleep disturbance, behavioural problems, and a variety of craniofacial, skeletal, and visceral anomalies. While the majority of SMS cases harbor an ~3.5 Mb common deletion on 17p11.2 that encompasses the retinoic acid induced-1 (RAI1 gene, some patients carry small intragenic deletions or point mutations in RAI1. We present data on two cases of Smith-Magenis syndrome with mutation of RAI1. Both cases are phenotypically consistent with SMS and RAI1 mutation but also have other anomalies not previously reported in SMS, including spontaneous pneumothoraces. These cases also illustrate variability in the SMS phenotype not previously shown for RAI1 mutation cases, including hearing loss, absence of self-abusive behaviours, and mild global delays. Sequencing of RAI1 revealed mutation of the same heptameric C-tract (CCCCCCC in exon 3 in both cases (c.3103delC one case and and c.3103insC in the other, resulting in frameshift mutations. Of the seven reported frameshift mutations occurring in poly C-tracts in RAI1, four cases (~57% occur at this heptameric C-tract. Collectively, these results indicate that this heptameric C-tract is a preferential hotspot for single nucleotide insertion/deletions (SNindels and therefore, should be considered a primary target for analysis in patients suspected for mutations in RAI1. We expect that as more patients are sequenced for mutations in RAI1, the incidence of frameshift mutations in this hotspot will become more evident.

  7. First report of a de novo germline mutation in the MLH1 gene

    Institute of Scientific and Technical Information of China (English)

    Rein P Stulp; Yvonne J Vos; Bart Mol; Arend Karrenbeld; Monique de Raad; Huub JC van der Mijle; Rolf H Sijmons

    2006-01-01

    Hereditary non-polyposis colorectal carcinoma (HNPCC)is an autosomal dominant disorder associated with colorectal and endometrial cancer and a range of other tumor types. Germline mutations in the DNA mismatch repair (MMR) genes, particularly MLH1, MSH2, and MSH6, underlie this disorder. The vast majority of these HNPCC-associated mutations have been proven,or assumed, given the family history of cancer, to be transmitted through several generations. To the best of our knowledge, only a single case of a de novo germline MMR gene mutation (in MSH2) has been reported till now. Here, we report a patient with a de novo mutation in MLH1. We identified a MLH1 Q701X truncating mutation in the blood lymphocytes of a male who had been diagnosed with rectal cancer at the age of 35. His family history of cancer was negative for the first- and second-degree relatives. The mutation could not be detected in the patient's parents and sibling and paternity was confirmed with a set of highly polymorphic markers. Non-penetrance and small family size is the common explanation of verified negative family histories of cancer in patients with a germline MMR gene mutation. However, in addition to some cases explained by non-paternity, de novo germline mutations should be considered as a possible explanation as well. As guidelines that stress not to restrict MMR gene mutation testing to patients with a positive family history are more widely introduced, more cases of de novo MMR gene germline mutations may be revealed.

  8. Two novel mutations involved in hereditary tyrosinemia type I

    Energy Technology Data Exchange (ETDEWEB)

    St-Louis, M.; Poudrier, J.; Phaneuf, D. [Univ. of Laval, Ste-Foy, Quebec (Canada)] [and others

    1994-09-01

    The deficiency of fumarylacetoacetate hydrolase, the last enzyme in the tyrosine catabolic pathway is the cause of hereditary tyrosinemia type I (HT1), an autosomal recessive disease. The disease has been reported worldwide. The incidence is much higher in two clusters: the Saguenay- Lac St-Jean region (Quebec, Canada) and in Scandinavia. Seven mutations have been reported in the last two years. Here we describe two new missense mutations identified by direct sequencing of PCR products in two HT1 patients, a Norwegian (patient No. 1) and a French-Canadian (patient No. 2). The first mutation consists of a G to A transition at position 337 of the FAH gene which predicts a change from glycine to serine (G337S). The second mutation is an A to G transition at position 381 which predicts a change from arginine to glycine (R381G). Patient No. 1 seems heterozygous for the G337S mutation and for a splice mutation (IVS12+5G{r_arrow}A) which was previously described. Patient No. 2 was also found heterozygous for the R381G mutation and for a rare nonsense mutation (E357X) already reported. In vitro transcription and translation were performed on mutant cDNA to demonstrate the responsibility of these two mutations in causing the decreased amount of FAH detected by Western blot analysis.

  9. Biochemical and molecular characterization of GALT gene from Indian galactosemia patients: identification of 10 novel mutations and their structural and functional implications.

    Science.gov (United States)

    Singh, Ramandeep; Thapa, Babu R; Kaur, Gurjit; Prasad, Rajendra

    2012-12-24

    Classical Galactosemia is an autosomal recessive disorder of galactose metabolism caused by severe reduction or absence of the galactose-1-phosphate uridyl transferase (GALT) enzyme. Till date, no reports are available on clinical and molecular spectrum of galactosemia from Indian population. The characterization of underlying GALT gene lesions was performed in 55 unrelated galactosemia patients. The GALT mutational spectrum comprised 16 distinct mutations including 10 previously unreported mutations. N314D was the most common mutation with a frequency of 40% followed by Q188R at 2.7%. The novel GALT gene mutations included 6 missense mutations viz. Y89H, Q103R, P166A, S181F, K285R, R333L; one nonsense mutation, S307X and 3 silent mutations--Q103Q, K210K and H319H. The functional significance of the novel GALT missense mutations was investigated using SNPs&GO and SIFT tools. Further, modeling studies using 3D models of mutant and wild type GALT proteins revealed mutations to exert their effects at the molecular level by altering H-bonds, salt bridges, secondary structure or surface features. The study highlighted the heterogeneity of classical galactosemia in the Indian population and also emphasizes the importance of GALT gene analysis in diagnosis of galactosemia. It also revealed that the Indian GALT mutational profile differs significantly from other populations studied.

  10. A novel mutation of the calcium-sensing receptor gene in a German subject with familial hypocalciuric hypercalcemia and primary hyperparathyroidism.

    Science.gov (United States)

    Papadakis, Marios; Meurer, Natalie; Margariti, Theodora; Meyer, Anke; Weyerbrock, Norbert; Dotzenrath, Cornelia

    2016-10-01

    The coexistence of familial hypocalciuric hypercalcemia (FHH) and primary hyperparathyroidism (PHPT) is extremely rare. Genetic evidence has demonstrated a causal relationship between FHH and the presence of inactivating mutations in the calcium-sensing receptor gene. We herein report a 60-year-old German patient who was referred for hypercalcemia and increased PTH levels found incidentally during normal routine blood tests. The patient underwent surgical exploration and the diagnosis of PHPT was histologically confirmed. One week later, the follow-up blood tests revealed recurrent hypercalcemia, and the possibility of FHH was reconsidered. Genetic analysis was performed and revealed a novel heterozygous CaSR single missense mutation (Arg551Gly) within the extracellular CaSR domain. We report a novel heterozygous missense inactivating mutation within the extracellular CaSR domain in a German subject with FHH and histologically proven PHPT.

  11. Novel DDR2 mutation identified by whole exome sequencing in a Moroccan patient with spondylo-meta-epiphyseal dysplasia, short limb-abnormal calcification type.

    Science.gov (United States)

    Mansouri, Maria; Kayserili, Hülya; Elalaoui, Siham Chafai; Nishimura, Gen; Iida, Aritoshi; Lyahyai, Jaber; Miyake, Noriko; Matsumoto, Naomichi; Sefiani, Abdelaziz; Ikegawa, Shiro

    2016-02-01

    Spondylo-meta-epiphyseal dysplasia (SMED), short limb-abnormal calcification type (SMED, SL-AC), is a very rare autosomal recessive disorder with various skeletal changes characterized by premature calcification leading to severe disproportionate short stature. Twenty-two patients have been reported until now, but only five mutations (four missense and one splice-site) in the conserved sequence encoding the tyrosine kinase domain of the DDR2 gene has been identified. We report here a novel DDR2 missense mutation, c.370C > T (p.Arg124Trp) in a Moroccan girl with SMED, SL-AC, identified by whole exome sequencing. Our study has expanded the mutational spectrum of this rare disease and it has shown that exome sequencing is a powerful and cost-effective tool for the diagnosis of clinically heterogeneous disorders such as SMED.

  12. Molecular Investigation of Leber’s Hereditary Optic Neuropathy Common Mutations in Suspected Patients

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    HR Soleimanpour

    2004-08-01

    Full Text Available LHON is a mitochondrial neurodegenerative disorder often manifesting itself in the second or third decade of life, and hence resulting in progressive central vision loss usually in a short period of 2-8 weeks within which different degrees of blindness may occur. Etiologically, more than twenty missense mutations have been reported for LHON, amongst which the three mutations of G11778A, G3460A and T14484C, affecting NADH dehydrogenase complex activity, are recognized as primary mutations. The three primary mutations account for 90% of LHON patients, emphasizing the importance of molecular investigation of these mutations for differential diagnosis of LHON. Using PCR-RFLP, this research resulted in the detection of two LHON families carrying the G11778A mutation in homoplasmy and described the clinical and molecular features of the disease in the patients.

  13. Novel Mutations in the CLCN1 Gene of Myotonia Congenita: 2 Case Reports

    Science.gov (United States)

    Lakraj, Amanda Amrita; Miller, Geoffrey; Vortmeyer, Alexander O.; Khokhar, Babar; Nowak, Richard J.; DiCapua, Daniel B.

    2013-01-01

    Introduction: Myotonia Congenita is an inherited myotonia that is due to a mutation in the skeletal muscle chloride channel CLCN1. These mutations lead to reduced sarcolemmal chloride conductance, causing delayed muscle relaxation that is evident as clinical and electrical myotonia. Methods: We report the clinical presentations of two individuals with Myotonia Congenita (MC). Results: Patient 1 has been diagnosed with the recessive form of MC, known as the Becker variant, and Patient 2 has been diagnosed with the dominant form of MC, known as the Thomsen variant. In both patients, the diagnosis was made based on the clinical presentation, EMG and CLCN1 gene sequencing. Patient 1 also had a muscle biopsy. Conclusions: Genetic testing in both patients reveals previously unidentified mutations in the CLCN1 gene specific to Myotonia Congenita. We report the salient clinical features of each patient and discuss the effects and common types of CLCN1 mutations and review the literature. PMID:23483815

  14. Mutational analysis of paediatric patients with tuberous sclerosis complex in Korea: genotype and epilepsy.

    Science.gov (United States)

    Lee, Jin Sook; Lim, Byung Chan; Chae, Jong-Hee; Hwang, Yong Seung; Seong, Moon-Woo; Park, Sung Sup; Kim, Ki Joong

    2014-12-01

    To date, only a few studies have reported that, in tuberous sclerosis, TSC2 mutations are more frequently associated with infantile spasms and cognitive impairment compared to TSC1 mutations. We analyzed the mutational spectrum of patients with tuberous sclerosis in Korea and attempted to explore the associations between genotype and seizure type/outcome. We performed mutational analyses on 70 unrelated patients with clinically confirmed tuberous sclerosis by using direct DNA sequencing and/or multiplex ligation-dependent probe amplification. The patients' medical records, including epilepsy type and outcome, were reviewed retrospectively. We identified pathogenic mutations in 55 patients (79%), 25 of which were novel. There were 12 TSC1 mutations and 43 TSC2 mutations. TSC1 mutations included 8 frameshift and 4 nonsense mutations. TSC2 mutations included 12 frameshift, 10 nonsense, 6 splicing, and 6 missense mutations, as well as 4 in-frame deletions and 5 large deletions. Fifty-eight patients had epilepsy (83%), including 19 patients with a history of infantile spasms. Compared to patients with TSC1 mutations, individuals with TSC2 mutations had a significantly higher frequency of epilepsy (p<0.05) and tended to have a higher frequency of infantile spasms (37% vs 17%; p<0.3). Most of the patients with TSC2 mutations who developed infantile spasms exhibited subsequent epilepsy (13/14; 93%). However, the presence/absence of infantile spasms did not influence seizure remission or cognitive outcome.

  15. Disease-associated mutations prevent GPR56-collagen III interaction.

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    Rong Luo

    Full Text Available GPR56 is a member of the adhesion G protein-coupled receptor (GPCR family. Mutations in GPR56 cause a devastating human brain malformation called bilateral frontoparietal polymicrogyria (BFPP. Using the N-terminal fragment of GPR56 (GPR56(N as a probe, we have recently demonstrated that collagen III is the ligand of GPR56 in the developing brain. In this report, we discover a new functional domain in GPR56(N, the ligand binding domain. This domain contains four disease-associated mutations and two N-glycosylation sites. Our study reveals that although glycosylation is not required for ligand binding, each of the four disease-associated mutations completely abolish the ligand binding ability of GPR56. Our data indicates that these four single missense mutations cause BFPP mostly by abolishing the ability of GPR56 to bind to its ligand, collagen III, in addition to affecting GPR56 protein surface expression as previously shown.

  16. Multigene testing of moderate-risk genes: be mindful of the missense

    Science.gov (United States)

    Young, E L; Feng, B J; Stark, A W; Damiola, F; Durand, G; Forey, N; Francy, T C; Gammon, A; Kohlmann, W K; Kaphingst, K A; McKay-Chopin, S; Nguyen-Dumont, T; Oliver, J; Paquette, A M; Pertesi, M; Robinot, N; Rosenthal, J S; Vallee, M; Voegele, C; Hopper, J L; Southey, M C; Andrulis, I L; John, E M; Hashibe, M; Gertz, J; Le Calvez-Kelm, F; Lesueur, F; Goldgar, D E; Tavtigian, S V

    2016-01-01

    Background Moderate-risk genes have not been extensively studied, and missense substitutions in them are generally returned to patients as variants of uncertain significance lacking clearly defined risk estimates. The fraction of early-onset breast cancer cases carrying moderate-risk genotypes and quantitative methods for flagging variants for further analysis have not been established. Methods We evaluated rare missense substitutions identified from a mutation screen of ATM, CHEK2, MRE11A, RAD50, NBN, RAD51, RINT1, XRCC2 and BARD1 in 1297 cases of early-onset breast cancer and 1121 controls via scores from Align-Grantham Variation Grantham Deviation (GVGD), combined annotation dependent depletion (CADD), multivariate analysis of protein polymorphism (MAPP) and PolyPhen-2. We also evaluated subjects by polygenotype from 18 breast cancer risk SNPs. From these analyses, we estimated the fraction of cases and controls that reach a breast cancer OR≥2.5 threshold. Results Analysis of mutation screening data from the nine genes revealed that 7.5% of cases and 2.4% of controls were carriers of at least one rare variant with an average OR≥2.5. 2.1% of cases and 1.2% of controls had a polygenotype with an average OR≥2.5. Conclusions Among early-onset breast cancer cases, 9.6% had a genotype associated with an increased risk sufficient to affect clinical management recommendations. Over two-thirds of variants conferring this level of risk were rare missense substitutions in moderate-risk genes. Placement in the estimated OR≥2.5 group by at least two of these missense analysis programs should be used to prioritise variants for further study. Panel testing often creates more heat than light; quantitative approaches to variant prioritisation and classification may facilitate more efficient clinical classification of variants. PMID:26787654

  17. Porencephaly in a fetus and HANAC in her father: variable expression of COL4A1 mutation.

    Science.gov (United States)

    Takenouchi, Toshiki; Ohyagi, Masaki; Torii, Chiharu; Kosaki, Rika; Takahashi, Takao; Kosaki, Kenjiro

    2015-01-01

    COL4A1-associated disorders encompass a wide range of hereditary vasculopathy, including porencephaly and HANAC (adult-onset hemorrhagic stroke with cerebral aneurysm and retinal arterial tortuosity, renal cysts, and thenar muscle cramp). It remains elusive whether or not porencephaly and HANAC are molecularly distinctive disorders due to different classes of mutations. We report on a girl with porencephaly and an episode of microangiopathic hemolysis in infancy and her father with HANAC, both of whom had a heterozygous missense mutation of COL4A1 (c.3715G>A, p.G1239R). The current observation implies phenotypic diversities of COL4A1 mutations.

  18. Novel de novo mutations in ZBTB20 in Primrose syndrome with congenital hypothyroidism.

    Science.gov (United States)

    Mattioli, Francesca; Piton, Amelie; Gérard, Bénédicte; Superti-Furga, Andrea; Mandel, Jean-Louis; Unger, Sheila

    2016-06-01

    The cardinal features of Primrose syndrome (MIM 259050) are dysmorphic facial features, macrocephaly, and intellectual disability, as well as large body size, height and weight, and calcified pinnae. A variety of neurological signs and symptoms have been reported including hearing loss, autism, behavioral abormalities, hypotonia, cerebral calcifications, and hypoplasia of the corpus callosum. Recently, heterozygous de novo missense mutations in ZBTB20, coding for a zing finger protein, have been identified in Primrose syndrome patients. We report a boy with intellectual disability carrying two de novo missense mutations in the last exon of ZBTB20 (Ser616Phe and Gly741Arg; both previously unreported). One of them, Ser616Phe, affects an amino acid located in one of the C2H2 zing-fingers involved in DNA-binding and close to other missense mutations already described. Reverse phenotyping showed that this patient presents with classic features of Primrose syndrome (dysmorphic facies, macrocephaly, hearing loss, hypotonia, hypoplasia of the corpus callosum) and, in addition, congenital hypothyroidism. Review of the literature reveals another Primrose syndrome patient with hypothyroidism and thus, this may represent an under recognized component that should be investigated in other patients. © 2016 Wiley Periodicals, Inc.

  19. GNA11 Mutation in a Patient With Cutaneous Origin Melanoma: A Case Report.

    Science.gov (United States)

    Patel, Sapna P; Kim, Dae Won; Lacey, Carol L; Hwu, Patrick

    2016-01-01

    The rapid advances in the molecular biology and genetics have improved the understanding of molecular pathogenesis of v-Raf murine sarcoma viral oncogene homolog B (BRAF), feline sarcoma viral oncogene v-kit (KIT), and neuroblastoma v-Ras oncogene homolog (NRAS) mutant melanomas with the subsequent development of targeted therapeutic agents. However, only limited data are available for melanoma harboring other somatic than BRAF, KIT, and NRAS mutations. Mutations in guanine nucleotide-binding protein Q polypeptide (GNAQ) and guanine nucleotide-binding protein alpha-11 (GNA11), alpha subunits of heterotrimeric G proteins, constitutively activate mitogen-activated protein kinase (MAPK) pathway in uveal melanoma. However, there are no reports of GNA11 mutations in cutaneous melanomas. A 48-year-old woman was diagnosed with cutaneous nodular melanoma on the left scalp. Mutation analysis of the tumor revealed a GNA11 Q209L mutation. There was no evidence of uveal melanoma or malignant blue nevus in ophthalmologic exam, imaging studies, and pathology review. To our knowledge, this is the first case report to demonstrate cutaneous origin melanoma harboring a GNA11 Q209L mutation.

  20. Mutations of SCN4A gene cause different diseases: 2 case reports and literature review.

    Science.gov (United States)

    Liu, Xiao-li; Huang, Xiao-jun; Luan, Xing-hua; Zhou, Hai-yan; Wang, Tian; Wang, Jing-yi; Chen, Sheng-di; Tang, Hui-dong; Cao, Li

    2015-01-01

    SCN4A encodes the Nav1.4 channel and mutations in SCN4A lead to different ionic channelopathies. In this study, one sporadic individual of periodic paralysis, one paramyotonia family and 200 normal healthy controls are enrolled. Genomic DNA was extracted from peripheral blood leukocytes, followed by polymerase chain reaction and DNA sequencing of candidate genes, including SCN4A and CACNA1S. As a result, heterozygous mutations c.2024G>A (R675Q) and c.1333G>A (V445M) of gene SCN4A were identified in the hypokalemic periodic paralysis patient and the paramyotonia congenita family respectively. Both mutations were not detected in healthy controls. Compared with reported cases, patients with mutation R675Q usually do not present hypokalemic periodic paralysis but hyperkalemic or normokalemic periodic paralysis. The mutation V445M was first reported in Chinese patients with nondystrophic myotonias. In addition, we carried out literature review by summarizing clinical features of the 2 mutations and establish the genotype-phenotype correlations to provide guidance for diagnosis.

  1. Case report of novel CACNA1A gene mutation causing episodic ataxia type 2

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    David Alan Isaacs

    2017-05-01

    Full Text Available Background: Episodic ataxia type 2 (OMIM 108500 is an autosomal dominant channelopathy characterized by paroxysms of ataxia, vertigo, nausea, and other neurologic symptoms. More than 50 mutations of the CACNA1A gene have been discovered in families with episodic ataxia type 2, although 30%–50% of all patients with typical episodic ataxia type 2 phenotype have no detectable mutation of the CACNA1A gene. Case: A 46-year-old Caucasian man, with a long history of bouts of imbalance, vertigo, and nausea, presented to our hospital with 2 weeks of ataxia and headache. Subsequent evaluation revealed a novel mutation in the CACNA1A gene: c.1364 G > A Arg455Gln. Acetazolamide was initiated with symptomatic improvement. Conclusion: This case report expands the list of known CACNA1A mutations associated with episodic ataxia type 2.

  2. Case report of novel CACNA1A gene mutation causing episodic ataxia type 2.

    Science.gov (United States)

    Isaacs, David Alan; Bradshaw, Michael J; Brown, Kelly; Hedera, Peter

    2017-01-01

    Episodic ataxia type 2 (OMIM 108500) is an autosomal dominant channelopathy characterized by paroxysms of ataxia, vertigo, nausea, and other neurologic symptoms. More than 50 mutations of the CACNA1A gene have been discovered in families with episodic ataxia type 2, although 30%-50% of all patients with typical episodic ataxia type 2 phenotype have no detectable mutation of the CACNA1A gene. A 46-year-old Caucasian man, with a long history of bouts of imbalance, vertigo, and nausea, presented to our hospital with 2 weeks of ataxia and headache. Subsequent evaluation revealed a novel mutation in the CACNA1A gene: c.1364 G > A Arg455Gln. Acetazolamide was initiated with symptomatic improvement. This case report expands the list of known CACNA1A mutations associated with episodic ataxia type 2.

  3. Ubiquitin ligases of the N-end rule pathway: assessment of mutations in UBR1 that cause the Johanson-Blizzard syndrome.

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    Cheol-Sang Hwang

    Full Text Available BACKGROUND: Johanson-Blizzard syndrome (JBS; OMIM 243800 is an autosomal recessive disorder that includes congenital exocrine pancreatic insufficiency, facial dysmorphism with the characteristic nasal wing hypoplasia, multiple malformations, and frequent mental retardation. Our previous work has shown that JBS is caused by mutations in human UBR1, which encodes one of the E3 ubiquitin ligases of the N-end rule pathway. The N-end rule relates the regulation of the in vivo half-life of a protein to the identity of its N-terminal residue. One class of degradation signals (degrons recognized by UBR1 are destabilizing N-terminal residues of protein substrates. METHODOLOGY/PRINCIPAL FINDINGS: Most JBS-causing alterations of UBR1 are nonsense, frameshift or splice-site mutations that abolish UBR1 activity. We report here missense mutations of human UBR1 in patients with milder variants of JBS. These single-residue changes, including a previously reported missense mutation, involve positions in the RING-H2 and UBR domains of UBR1 that are conserved among eukaryotes. Taking advantage of this conservation, we constructed alleles of the yeast Saccharomyces cerevisiae UBR1 that were counterparts of missense JBS-UBR1 alleles. Among these yeast Ubr1 mutants, one of them (H160R was inactive in yeast-based activity assays, the other one (Q1224E had a detectable but weak activity, and the third one (V146L exhibited a decreased but significant activity, in agreement with manifestations of JBS in the corresponding JBS patients. CONCLUSIONS/SIGNIFICANCE: These results, made possible by modeling defects of a human ubiquitin ligase in its yeast counterpart, verified and confirmed the relevance of specific missense UBR1 alleles to JBS, and suggested that a residual activity of a missense allele is causally associated with milder variants of JBS.

  4. Mutation Analysis of Gap Junction Protein Beta 1 and Genotype-Phenotype Correlation in X-linked Charcot-Marie-Tooth Disease in Chinese Patients

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    Bo Sun

    2016-01-01

    Conclusions: The three novel missense mutations within the GJB1 gene broaden the mutational diversity of CMT1X. Molecular analysis of family members and bioinformatics analyses of the afflicted patients confirmed the pathogenicity of these mutations.

  5. Two novel mutations of CLCN7 gene in Chinese families with autosomal dominant osteopetrosis (type II).

    Science.gov (United States)

    Zheng, Hui; Shao, Chong; Zheng, Yan; He, Jin-Wei; Fu, Wen-Zhen; Wang, Chun; Zhang, Zhen-Lin

    2016-07-01

    Autosomal dominant osteopetrosis type II (ADO-II) is a heritable bone disorder characterized by osteosclerosis, predominantly involving the spine (vertebral end-plate thickening, or rugger-jersey spine), the pelvis ("bone-within-bone" structures) and the skull base. Chloride channel 7 (CLCN7) has been reported to be the causative gene. In this study, we aimed to identify the pathogenic mutation in four Chinese families with ADO-II. All 25 exons of the CLCN7 gene, including the exon-intron boundaries, were amplified and sequenced directly in four probands from the Chinese families with ADO-II. The mutation site was then identified in other family members and 250 healthy controls. In family 1, a known missense mutation c.296A>G in exon 4 of CLCN7 was identified in the proband, resulting in a tyrosine (UAU) to cysteine (UGU) substitution at p.99 (Y99C); the mutation was also identified in his affected father. In family 2, a novel missense mutation c.865G>C in exon 10 was identified in the proband, resulting in a valine (GUC) to leucine (CUC) substitution at p.289 (V289L); the mutation was also identified in her healthy mother and sister. In family 3, a novel missense mutation c.1625C>T in exon 17 of CLCN7 was identified in the proband, resulting in an alanine (GCG) to valine (GUG) substitution at p.542 (A542V); the mutation was also identified in her father. In family 4, a hot spot, R767W (c.2299C>T, CGG>TGG), in exon 24 was found in the proband which once again proved the susceptibility of the site or the similar genetic background in different races. Moreover, two novel mutations, V289L and A542V, occurred at a highly conserved position, found by a comparison of the protein sequences from eight vertebrates, and were predicted to have a pathogenic effect by PolyPhen-2 software, which showed "probably damaging" with a score of approximately 1. These mutation sites were not identified in 250 healthy controls. Our present findings suggest that the novel missense

  6. CACNA1A基因的错义突变R1345Q导致一种新的共济失调伴随发作性全身震颤:临床特征、基因诊断及治疗的家系分析%Missense mutation R1345Q in CACNA1A gene causes a new type of ataxia with episodic tremor:clinical features, genetic analysis and treatment in a familial case

    Institute of Scientific and Technical Information of China (English)

    蒋海山; 王冬梅; 王群; 杨曼; 王伟; 潘速跃; 胡亚芳

    2016-01-01

    目的: CACNA1A基因编码P/Q型钙离子通道的亚单位,它的突变至少造成3种等位基因病:发作性共济失调2型(EA-2)、家族性偏瘫性偏头痛1型(FHM1)和小脑脊髓共济失调6型(SCA 6)。本研究对一例19岁男性的发作性全身震颤患者的临床表现、基因分析结果和治疗效果进行研究。方法对病人及家系中有类似症状的成员进行专科查体;对先证者的DNA进行下一代测序分析以寻找致病基因,并用Sanger测序方法对家系成员进行基因变异的验证。结果神经专科查体显示患者共济失调体征,醉酒步态,头和躯干震颤。家系中另4个成员的症状和体征较轻。基因检测发现先证者携带有CACNA1A基因的杂合错义突变(NM_001127221.1 c.4034G->A, p.R1345Q, exon 25),为致病突变。家系中4个患病成员中也携带同样杂合突变。病人经醋甲唑胺治疗后效果不佳,但钙离子通道阻断剂西比灵治疗效果良好。结论根据患者的临床表现、基因突变类型和治疗效果,我们认为患者CACNA1A基因突变R1345Q所引起的疾病不属于EA2,FHM1,或SCA 6任何一种,而是一种新的伴有发作性震颤共济失调。%Objective Mutations in CACNA1A, which encodes the P/Q-type calcium channel subunit, are responsible for at least 3 allelic diseases, namely type 2 episodic ataxia (EA-2), familial hemiplegic migraine type-1 (FHM1), and spinocerebellar ataxia type-6 (SCA 6). Herein we present a case of ataxia with episodic tremors in a 19-year-old man with a missense mutation of CACNA1A gene and summarize the clinical features, genetic analysis and treatment in this case and in his affected family members. Methods Physical examinations were conducted for the patient and his affected family members. DNA sample from the proband was analyzed with next-generation sequencing technology to identify the causative mutation. Sanger sequencing was used to confirm the gene

  7. Codon-specific missense errors in vivo.

    Science.gov (United States)

    Bouadloun, F; Donner, D; Kurland, C G

    1983-01-01

    We have developed a simple method for measuring the missense substitution of amino acids at specified positions in proteins synthesized in vivo. We find that the frequency of cysteine substitution for the single arginine in Escherichia coli ribosomal protein L7/L12 is close to 10(-3) for wild-type bacteria, decreases to 4 x 10(-4) in streptomycin-resistant bacteria containing mutant S12 (rpsL), and is virtually unchanged in Ram bacteria containing mutant S4 (rpsD). We have also found that the frequency of the cysteine substitution for the single tryptophan in E. coli ribosomal protein S6 is 3-4 x 10(-3) for wild-type bacteria, decreases to 6 x 10(-4) in streptomycin-resistant bacteria and is elevated to nearly 10(-2) in Ram bacteria.

  8. NIPA1 mutation in complex hereditary spastic paraplegia with epilepsy

    DEFF Research Database (Denmark)

    Svenstrup, Kirsten; Møller, R S; Christensen, Jacob

    2011-01-01

    or signs are found. Mutations in the NIPA1 gene have been reported to cause spastic paraplegia type 6 (SPG6) in 10 families. SPG6 is a rare form of autosomal dominantly inherited HSP associated with a pure phenotype; however, in one complex SPG6 family, idiopathic generalized epilepsy (IGE) has been...... reported missense mutation c.316G>A, p.Gly106Arg, was identified in a complex HSP patient with spastic dysarthria, facial dystonia, atrophy of the small hand muscles, upper limb spasticity, and presumably IGE. The epilepsy co-segregated with HSP in the family. Conclusion: NIPA1 mutations were rare in our...... population of patients with HSP, but can be found in patients with complex HSP. Epilepsy might be more common in SPG6 than in other forms of HSP because of a genetic risk factor closely linked to NIPA1....

  9. Mutations in TMEM231 cause Meckel-Gruber syndrome.

    Science.gov (United States)

    Shaheen, Ranad; Ansari, Shinu; Mardawi, Elham Al; Alshammari, Muneera J; Alkuraya, Fowzan S

    2013-03-01

    Meckel-Gruber syndrome (MKS) is a genetically heterogeneous severe ciliopathy characterised by early lethality, occipital encephalocele, polydactyly, and polycystic kidney disease. To report genetic analysis results in two families in which all known MKS diseases genes have been excluded. In two consanguineous families with classical MKS in which autozygome-guided sequencing of previously reported MKS genes was negative, we performed exome sequencing followed by autozygome filtration. We identified one novel splicing mutation in TMEM231, which led to complete degradation of the mutant transcript in one family, and a novel missense mutation in the other, both in the homozygous state. TMEM231 represents a novel MKS locus. The very recent identification of TMEM231 mutations in Joubert syndrome supports the growing appreciation of the overlap in the molecular pathogenesis between these two ciliopathies.

  10. Mutations in TMEM231 cause Meckel–Gruber syndrome

    Science.gov (United States)

    Shaheen, Ranad; Ansari, Shinu; Mardawi, Elham AL; Alshammari, Muneera J; Alkuraya, Fowzan S

    2013-01-01

    Background Meckel–Gruber syndrome (MKS) is a genetically heterogeneous severe ciliopathy characterised by early lethality, occipital encephalocele, polydactyly, and polycystic kidney disease. Purpose To report genetic analysis results in two families in which all known MKS diseases genes have been excluded. Methods In two consanguineous families with classical MKS in which autozygome-guided sequencing of previously reported MKS genes was negative, we performed exome sequencing followed by autozygome filtration. Results We identified one novel splicing mutation in TMEM231, which led to complete degradation of the mutant transcript in one family, and a novel missense mutation in the other, both in the homozygous state. Conclusions TMEM231 represents a novel MKS locus. The very recent identification of TMEM231 mutations in Joubert syndrome supports the growing appreciation of the overlap in the molecular pathogenesis between these two ciliopathies. PMID:23349226

  11. Clinical features andMUT gene mutation spectrum in Chinese patients with isolated methylmalonic acidemia:identifi cation of ten novel allelic variants

    Institute of Scientific and Technical Information of China (English)

    Lian-Shu Han; Zhuo Huang; Feng Han; Jun Ye; Wen-Juan Qiu; Hui-Wen Zhang; Yu Wang; Zhu-Wen Gong; Xue-Fan Gu

    2015-01-01

    Background: This study aims to studyMUT gene mutation spectrum in Chinese patients with isolated methylmalonic academia (MMA) and their clinical features for the potential genotype-phenotype correlation. Methods: Forty-three patients were diagnosed with isolated MMA by elevated blood propionylcarnitine, propionylcarnitine to acetylcarnitine ratio, and urine methylmalonate without hyperhomocysteinemia. The MUT gene was amplifi ed by polymerase chain reaction and directly sequenced. Those patients with at least one variant allele were included. The novel missense mutations were assessed by bioinformatic analysis and screened against alleles sequenced from 50 control participants. Results: Among the 43 patients, 38 had typical clinical presentations, and the majority (30/38) experienced early-onset MMA. Eight patients died and seven were lost to follow-up. Twenty patients had poor outcomes and eight showed normal development. The 43 identifi edMUT gene mutations had at least one variant allele, whereas 35 had two mutant alleles. Of the 33 mutations reported before, eight recurrent mutations were identified in 32 patients, and c.729_730insTT (p.D244Lfs*39) was the most common (12/78) in the mutant alleles. Of the 10 novel mutations, six were missense mutations and four were premature termination codon mutations. The six novel missense mutations seemed to be pathogenic. Conclusions: A total of 10 novelMUT mutations were detected in the Chinese population. c.729_730insTT (p.D244Lfs*39) was the most frequent mutation. A genotype-phenotype correlation could not be found, but the genotypic characterization indicated the need of genetic counseling for MMA patients and early prenatal diagnoses for high-risk families.

  12. Adenylosuccinate lyase (ADSL) and infantile autism: Absence of previously reported point mutation

    Energy Technology Data Exchange (ETDEWEB)

    Fon, E.A.; Sarrazin, J.; Rouleau, G.A. [Montreal General Hospital (Canada)] [and others

    1995-12-18

    Autism is a heterogeneous neuropsychiatric syndrome of unknown etiology. There is evidence that a deficiency in the enzyme adenylosuccinate lyase (ADSL), essential for de novo purine biosynthesis, could be involved in the pathogenesis of certain cases. A point