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Sample records for enu-induced mutation causing

  1. ENU-induced phenovariance in mice: inferences from 587 mutations

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    Arnold Carrie N

    2012-10-01

    Full Text Available Abstract Background We present a compendium of N-ethyl-N-nitrosourea (ENU-induced mouse mutations, identified in our laboratory over a period of 10 years either on the basis of phenotype or whole genome and/or whole exome sequencing, and archived in the Mutagenetix database. Our purpose is threefold: 1 to formally describe many point mutations, including those that were not previously disclosed in peer-reviewed publications; 2 to assess the characteristics of these mutations; and 3 to estimate the likelihood that a missense mutation induced by ENU will create a detectable phenotype. Findings In the context of an ENU mutagenesis program for C57BL/6J mice, a total of 185 phenotypes were tracked to mutations in 129 genes. In addition, 402 incidental mutations were identified and predicted to affect 390 genes. As previously reported, ENU shows strand asymmetry in its induction of mutations, particularly favoring T to A rather than A to T in the sense strand of coding regions and splice junctions. Some amino acid substitutions are far more likely to be damaging than others, and some are far more likely to be observed. Indeed, from among a total of 494 non-synonymous coding mutations, ENU was observed to create only 114 of the 182 possible amino acid substitutions that single base changes can achieve. Based on differences in overt null allele frequencies observed in phenotypic vs. non-phenotypic mutation sets, we infer that ENU-induced missense mutations create detectable phenotype only about 1 in 4.7 times. While the remaining mutations may not be functionally neutral, they are, on average, beneath the limits of detection of the phenotypic assays we applied. Conclusions Collectively, these mutations add to our understanding of the chemical specificity of ENU, the types of amino acid substitutions it creates, and its efficiency in causing phenovariance. Our data support the validity of computational algorithms for the prediction of damage caused by

  2. Novel ENU-Induced Mutation in Tbx6 Causes Dominant Spondylocostal Dysostosis-Like Vertebral Malformations in the Rat.

    Science.gov (United States)

    Abe, Koichiro; Takamatsu, Nobuhiko; Ishikawa, Kumiko; Tsurumi, Toshiko; Tanimoto, Sho; Sakurai, Yukina; Lisse, Thomas S; Lisse, Thomas; Imai, Kenji; Serikawa, Tadao; Mashimo, Tomoji

    2015-01-01

    Congenital vertebral malformations caused by embryonic segmentation defects are relatively common in humans and domestic animals. Although reverse genetics approaches in mice have provided information on the molecular mechanisms of embryonic somite segmentation, hypothesis-driven approaches cannot adequately reflect human dysmorphology within the population. In a N-ethyl-N-nitrosourea (ENU) mutagenesis project in Kyoto, the Oune mutant rat strain was isolated due to a short and kinked caudal vertebra phenotype. Skeletal staining of heterozygous rats showed partial loss of the cervical vertebrae as well as hemivertebrae and fused vertebral blocks in lumbar and sacral vertebrae. In homozygous embryos, severe displacement of the whole vertebrae was observed. The Oune locus was genetically mapped to rat chromosome 1 using 202 backcross animals and 50 genome-wide microsatellite markers. Subsequently, a miss-sense mutation in the Tbx6 gene was identified in the critical region. Although the mutation is located within the T-box domain near a predicted dimmer-interface, in vitro experiments revealed that the Tbx6 variant retains normal DNA binding ability and translational efficiency. However, the variant has decreased transcriptional activation potential in response to Notch-mediated signaling. Recently, it was reported that a dominant type of familial spondylocostal dysostosis is caused by a stoploss mutation in TBX6. Thus, we propose that partial dysfunction of Tbx6 leads to similar congenital vertebral malformations in both humans and rats. The Oune strain could be a unique animal model for dominant spondylocostal dysostosis and is useful for molecular dissection of the pathology of congenital vertebral malformations in humans.

  3. Novel ENU-Induced Mutation in Tbx6 Causes Dominant Spondylocostal Dysostosis-Like Vertebral Malformations in the Rat.

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    Koichiro Abe

    Full Text Available Congenital vertebral malformations caused by embryonic segmentation defects are relatively common in humans and domestic animals. Although reverse genetics approaches in mice have provided information on the molecular mechanisms of embryonic somite segmentation, hypothesis-driven approaches cannot adequately reflect human dysmorphology within the population. In a N-ethyl-N-nitrosourea (ENU mutagenesis project in Kyoto, the Oune mutant rat strain was isolated due to a short and kinked caudal vertebra phenotype. Skeletal staining of heterozygous rats showed partial loss of the cervical vertebrae as well as hemivertebrae and fused vertebral blocks in lumbar and sacral vertebrae. In homozygous embryos, severe displacement of the whole vertebrae was observed. The Oune locus was genetically mapped to rat chromosome 1 using 202 backcross animals and 50 genome-wide microsatellite markers. Subsequently, a miss-sense mutation in the Tbx6 gene was identified in the critical region. Although the mutation is located within the T-box domain near a predicted dimmer-interface, in vitro experiments revealed that the Tbx6 variant retains normal DNA binding ability and translational efficiency. However, the variant has decreased transcriptional activation potential in response to Notch-mediated signaling. Recently, it was reported that a dominant type of familial spondylocostal dysostosis is caused by a stoploss mutation in TBX6. Thus, we propose that partial dysfunction of Tbx6 leads to similar congenital vertebral malformations in both humans and rats. The Oune strain could be a unique animal model for dominant spondylocostal dysostosis and is useful for molecular dissection of the pathology of congenital vertebral malformations in humans.

  4. Identification of a Novel ENU-Induced Mutation in Mouse Tbx1 Linked to Human DiGeorge Syndrome

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    Jiaofeng Chen

    2016-01-01

    Full Text Available The patients with DiGeorge syndrome (DGS, caused by deletion containing dozens of genes in chromosome 22, often carry cardiovascular problem and hearing loss associated with chronic otitis media. Inside the deletion region, a transcription factor TBX1 was highly suspected. Furthermore, similar DGS phenotypes were found in the Tbx1 heterozygous knockout mice. Using ENU-induced mutagenesis and G1 dominant screening strategy, here we identified a nonsynonymous mutation p.W118R in T-box of TBX1, the DNA binding domain for transcription activity. The mutant mice showed deficiency of inner ear functions, including head tossing and circling, plus increased hearing threshold determined by audiometry. Therefore, our result further confirms the pathogenic basis of Tbx1 in DGS, points out the crucial role of DNA binding activity of TBX1 for the ear function, and provides additional animal model for studying the DGS disease mechanisms.

  5. CHARACTERIZATION OF ENU-INDUCED MUTATIONS IN RED BLOOD CELL STRUCTURAL PROTEINS

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    Katrina Kildey

    2013-03-01

    Full Text Available Murine models with modified gene function as a result of N-ethyl-N-nitrosourea (ENU mutagenesis have been used to study phenotypes resulting from genetic change. This study investigated genetic factors associated with red blood cell (RBC physiology and structural integrity that may impact on blood component storage and transfusion outcome. Forward and reverse genetic approaches were employed with pedigrees of ENU-treated mice using a homozygous recessive breeding strategy. In a “forward genetic” approach, pedigree selection was based upon identification of an altered phenotype followed by exome sequencing to identify a causative mutation. In a second strategy, a “reverse genetic” approach based on selection of pedigrees with mutations in genes of interest was utilised and, following breeding to homozygosity, phenotype assessed. Thirty-three pedigrees were screened by the forward genetic approach. One pedigree demonstrated reticulocytosis, microcytic anaemia and thrombocytosis. Exome sequencing revealed a novel single nucleotide variation (SNV in Ank1 encoding the RBC structural protein ankyrin-1 and the pedigree was designated Ank1EX34. The reticulocytosis and microcytic anaemia observed in the Ank1EX34 pedigree were similar to clinical features of hereditary spherocytosis in humans. For the reverse genetic approach three pedigrees with different point mutations in Spnb1 encoding RBC protein spectrin-1β, and one pedigree with a mutation in Epb4.1, encoding band 4.1 were selected for study. When bred to homozygosity two of the spectrin-1β pedigrees (a, b demonstrated increased RBC count, haemoglobin (Hb and haematocrit (HCT. The third Spnb1 mutation (spectrin-1β c and mutation in Epb4.1 (band 4.1 did not significantly affect the haematological phenotype, despite these two mutations having a PolyPhen score predicting the mutation may be damaging. Exome sequencing allows rapid identification of causative mutations and development of

  6. Fast homozygosity mapping and identification of a zebrafish ENU-induced mutation by whole-genome sequencing.

    Science.gov (United States)

    Voz, Marianne L; Coppieters, Wouter; Manfroid, Isabelle; Baudhuin, Ariane; Von Berg, Virginie; Charlier, Carole; Meyer, Dirk; Driever, Wolfgang; Martial, Joseph A; Peers, Bernard

    2012-01-01

    Forward genetics using zebrafish is a powerful tool for studying vertebrate development through large-scale mutagenesis. Nonetheless, the identification of the molecular lesion is still laborious and involves time-consuming genetic mapping. Here, we show that high-throughput sequencing of the whole zebrafish genome can directly locate the interval carrying the causative mutation and at the same time pinpoint the molecular lesion. The feasibility of this approach was validated by sequencing the m1045 mutant line that displays a severe hypoplasia of the exocrine pancreas. We generated 13 Gb of sequence, equivalent to an eightfold genomic coverage, from a pool of 50 mutant embryos obtained from a map-cross between the AB mutant carrier and the WIK polymorphic strain. The chromosomal region carrying the causal mutation was localized based on its unique property to display high levels of homozygosity among sequence reads as it derives exclusively from the initial AB mutated allele. We developed an algorithm identifying such a region by calculating a homozygosity score along all chromosomes. This highlighted an 8-Mb window on chromosome 5 with a score close to 1 in the m1045 mutants. The sequence analysis of all genes within this interval revealed a nonsense mutation in the snapc4 gene. Knockdown experiments confirmed the assertion that snapc4 is the gene whose mutation leads to exocrine pancreas hypoplasia. In conclusion, this study constitutes a proof-of-concept that whole-genome sequencing is a fast and effective alternative to the classical positional cloning strategies in zebrafish.

  7. Fast homozygosity mapping and identification of a zebrafish ENU-induced mutation by whole-genome sequencing.

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    Marianne L Voz

    Full Text Available Forward genetics using zebrafish is a powerful tool for studying vertebrate development through large-scale mutagenesis. Nonetheless, the identification of the molecular lesion is still laborious and involves time-consuming genetic mapping. Here, we show that high-throughput sequencing of the whole zebrafish genome can directly locate the interval carrying the causative mutation and at the same time pinpoint the molecular lesion. The feasibility of this approach was validated by sequencing the m1045 mutant line that displays a severe hypoplasia of the exocrine pancreas. We generated 13 Gb of sequence, equivalent to an eightfold genomic coverage, from a pool of 50 mutant embryos obtained from a map-cross between the AB mutant carrier and the WIK polymorphic strain. The chromosomal region carrying the causal mutation was localized based on its unique property to display high levels of homozygosity among sequence reads as it derives exclusively from the initial AB mutated allele. We developed an algorithm identifying such a region by calculating a homozygosity score along all chromosomes. This highlighted an 8-Mb window on chromosome 5 with a score close to 1 in the m1045 mutants. The sequence analysis of all genes within this interval revealed a nonsense mutation in the snapc4 gene. Knockdown experiments confirmed the assertion that snapc4 is the gene whose mutation leads to exocrine pancreas hypoplasia. In conclusion, this study constitutes a proof-of-concept that whole-genome sequencing is a fast and effective alternative to the classical positional cloning strategies in zebrafish.

  8. Discovery of candidate disease genes in ENU-induced mouse mutants by large-scale sequencing, including a splice-site mutation in nucleoredoxin.

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    Melissa K Boles

    2009-12-01

    Full Text Available An accurate and precisely annotated genome assembly is a fundamental requirement for functional genomic analysis. Here, the complete DNA sequence and gene annotation of mouse Chromosome 11 was used to test the efficacy of large-scale sequencing for mutation identification. We re-sequenced the 14,000 annotated exons and boundaries from over 900 genes in 41 recessive mutant mouse lines that were isolated in an N-ethyl-N-nitrosourea (ENU mutation screen targeted to mouse Chromosome 11. Fifty-nine sequence variants were identified in 55 genes from 31 mutant lines. 39% of the lesions lie in coding sequences and create primarily missense mutations. The other 61% lie in noncoding regions, many of them in highly conserved sequences. A lesion in the perinatal lethal line l11Jus13 alters a consensus splice site of nucleoredoxin (Nxn, inserting 10 amino acids into the resulting protein. We conclude that point mutations can be accurately and sensitively recovered by large-scale sequencing, and that conserved noncoding regions should be included for disease mutation identification. Only seven of the candidate genes we report have been previously targeted by mutation in mice or rats, showing that despite ongoing efforts to functionally annotate genes in the mammalian genome, an enormous gap remains between phenotype and function. Our data show that the classical positional mapping approach of disease mutation identification can be extended to large target regions using high-throughput sequencing.

  9. Mutations in LOXHD1, an Evolutionarily Conserved Stereociliary Protein, Disrupt Hair Cell Function in Mice and Cause Progressive Hearing Loss in Humans

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    Grillet, Nicolas; Schwander, Martin; Hildebrand, Michael S.; Sczaniecka, Anna; Kolatkar, Anand; Velasco, Janice; Webster, Jennifer A.; Kahrizi, Kimia; Najmabadi, Hossein; Kimberling, William J.; Stephan, Dietrich; Bahlo, Melanie; Wiltshire, Tim; Tarantino, Lisa M.; Kuhn, Peter; Smith, Richard J.H.; Müller, Ulrich

    2009-01-01

    Hearing loss is the most common form of sensory impairment in humans and is frequently progressive in nature. Here we link a previously uncharacterized gene to hearing impairment in mice and humans. We show that hearing loss in the ethylnitrosourea (ENU)-induced samba mouse line is caused by a mutation in Loxhd1. LOXHD1 consists entirely of PLAT (polycystin/lipoxygenase/α-toxin) domains and is expressed along the membrane of mature hair cell stereocilia. Stereociliary development is unaffected in samba mice, but hair cell function is perturbed and hair cells eventually degenerate. Based on the studies in mice, we screened DNA from human families segregating deafness and identified a mutation in LOXHD1, which causes DFNB77, a progressive form of autosomal-recessive nonsyndromic hearing loss (ARNSHL). LOXHD1, MYO3a, and PJVK are the only human genes to date linked to progressive ARNSHL. These three genes are required for hair cell function, suggesting that age-dependent hair cell failure is a common mechanism for progressive ARNSHL. PMID:19732867

  10. Recurrent LDL-receptor mutation causes familial ...

    African Journals Online (AJOL)

    1995-05-05

    May 5, 1995 ... mutation detection. Haplotype analysis with polymorphisms on both sides of the FH2 mutation indicated that the identical LDLR gene mutations found in two different South ... amplification refractory mutation system (ARMS)" and single- .... point mutations that cause familial defective apolipoprotein. 8-100 ...

  11. Mutations in ANTXR1 Cause GAPO Syndrome

    NARCIS (Netherlands)

    Stranecky, V.; Hoischen, A.; Hartmannova, H.; Zaki, M.S.; Chaudhary, A.; Zudaire, E.; Noskova, L.; Baresova, V.; Pristoupilova, A.; Hodanova, K.; Sovova, J.; Hulkova, H.; Piherova, L.; Hehir-Kwa, J.Y.; Silva, D. De; Senanayake, M.P.; Farrag, S.; Zeman, J.; Martasek, P.; Baxova, A.; Afifi, H.H.; Croix, B. St.; Brunner, H.G.; Temtamy, S.; Kmoch, S.

    2013-01-01

    The genetic cause of GAPO syndrome, a condition characterized by growth retardation, alopecia, pseudoanodontia, and progressive visual impairment, has not previously been identified. We studied four ethnically unrelated affected individuals and identified homozygous nonsense mutations (c.262C>T

  12. Common Variable Immunodeficiency Caused by FANC Mutations.

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    Sekinaka, Yujin; Mitsuiki, Noriko; Imai, Kohsuke; Yabe, Miharu; Yabe, Hiromasa; Mitsui-Sekinaka, Kanako; Honma, Kenichi; Takagi, Masatoshi; Arai, Ayako; Yoshida, Kenichi; Okuno, Yusuke; Shiraishi, Yuichi; Chiba, Kenichi; Tanaka, Hiroko; Miyano, Satoru; Muramatsu, Hideki; Kojima, Seiji; Hira, Asuka; Takata, Minoru; Ohara, Osamu; Ogawa, Seishi; Morio, Tomohiro; Nonoyama, Shigeaki

    2017-07-01

    Common variable immunodeficiency (CVID) is the most common adult-onset primary antibody deficiency disease due to various causative genes. Several genes, which are known to be the cause of different diseases, have recently been reported as the cause of CVID in patients by performing whole exome sequencing (WES) analysis. Here, we found FANC gene mutations as a cause of adult-onset CVID in two patients. B cells were absent and CD4 + T cells were skewed toward CD45RO + memory T cells. T-cell receptor excision circles (TRECs) and signal joint kappa-deleting recombination excision circles (sjKRECs) were undetectable in both patients. Both patients had no anemia, neutropenia, or thrombocytopenia. Using WES, we identified compound heterozygous mutations of FANCE in one patient and homozygous mutation of FANCA in another patient. The impaired function of FANC protein complex was confirmed by a monoubiquitination assay and by chromosome fragility test. We then performed several immunological evaluations including quantitative lymphocyte analysis and TRECs/sjKRECs analysis for 32 individuals with Fanconi anemia (FA). In total, 22 FA patients (68.8%) were found to have immunological abnormalities, suggesting that such immunological findings may be common in FA patients. These data indicate that FANC mutations are involved in impaired lymphogenesis probably by the accumulation of DNA replication stress, leading to CVID. It is important to diagnose FA because it drastically changes clinical management. We propose that FANC mutations can cause isolated immunodeficiency in addition to bone marrow failure and malignancy.

  13. Germline KRAS mutations cause Noonan syndrome.

    NARCIS (Netherlands)

    Schubbert, S.; Zenker, M.; Rowe, S.L.; Boll, S.; Klein, C.; Bollag, G.; Burgt, I. van der; Musante, L.; Kalscheuer, V.M.M.; Wehner, L.E.; Nguyen, H.; West, B.; Zhang, K.Y.; Sistermans, E.A.; Rauch, A.; Niemeyer, C.M.; Shannon, K.; Kratz, C.P.

    2006-01-01

    Noonan syndrome (MIM 163950) is characterized by short stature, facial dysmorphism and cardiac defects. Heterozygous mutations in PTPN11, which encodes SHP-2, cause approximately 50% of cases of Noonan syndrome. The SHP-2 phosphatase relays signals from activated receptor complexes to downstream

  14. Novel missense MTTP gene mutations causing abetalipoproteinemia.

    Science.gov (United States)

    Miller, Sharon A; Burnett, John R; Leonis, Mike A; McKnight, C James; van Bockxmeer, Frank M; Hooper, Amanda J

    2014-10-01

    The microsomal triglyceride transfer protein (MTTP) plays a critical role in the formation of hepatic very low density lipoprotein. Abetalipoproteinemia (ABL) is a rare, naturally occurring extreme form of MTTP inhibition, which is characterized by the virtual absence of apolipoprotein (apo) B-containing lipoproteins in blood. The goal of this study was to examine the effect that four novel MTTP missense mutations had on protein interactions, expression and lipid-transfer activity, and to determine which mutations were responsible for the ABL phenotype observed in two patients. In two patients with ABL, we identified in MTTP a novel frameshift mutation (K35Ffs*37), and four novel missense mutations, namely, G264R, Y528H, R540C, and N649S. When transiently expressed in COS-7 cells, all missense MTTP mutations interacted with apoB17, apoB48, and protein disulfide isomerase. Mutations Y528H and R540C, however, displayed negligible levels of MTTP activity and N649S displayed a partial reduction relative to the wild-type MTTP. In contrast, G264R retained full lipid-transfer activity. These studies indicate that missense mutations Y528H, R540C, and N649S appear to cause ABL by reducing MTTP activity rather than by reducing binding of MTTP with protein disulfide isomerase or apoB. The region of MTTP containing amino acids 528 and 540 constitutes a critical domain for its lipid-transfer activity. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. A Mutation in Mtap2 Is Associated with Arrest of Mammalian Spermatocytes before the First Meiotic Division

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    Fengyun Sun

    2011-01-01

    Full Text Available In spite of evolutionary conservation of meiosis, many of the genes that control mammalian meiosis are still unknown. We report here that the ENU-induced repro4 mutation, identified in a screen to uncover genes that control mouse meiosis, causes failure of spermatocytes to exit meiotic prophase I via the G2/MI transition. Major events of meiotic prophase I occurred normally in affected spermatocytes and known regulators of the meiotic G2/MI transition were present and functional. Deep sequencing of mutant DNA revealed a mutation located in an intron of the Mtap2 gene, encoding microtubule-associated protein 2, and levels of Mtap2 transcript were reduced in mutant testes. This evidence implicates MTAP2 as required directly or indirectly for completion of meiosis and normal spermatogenesis in mammals.

  16. Mutations in XRCC4 cause primordial dwarfism without causing immunodeficiency.

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    Saito, Shinta; Kurosawa, Aya; Adachi, Noritaka

    2016-08-01

    In successive reports from 2014 to 2015, X-ray repair cross-complementing protein 4 (XRCC4) has been identified as a novel causative gene of primordial dwarfism. XRCC4 is indispensable for non-homologous end joining (NHEJ), the major pathway for repairing DNA double-strand breaks. As NHEJ is essential for V(D)J recombination during lymphocyte development, it is generally believed that abnormalities in XRCC4 cause severe combined immunodeficiency. Contrary to expectations, however, no overt immunodeficiency has been observed in patients with primordial dwarfism harboring XRCC4 mutations. Here, we describe the various XRCC4 mutations that lead to disease and discuss their impact on NHEJ and V(D)J recombination.

  17. FAT1 mutations cause a glomerulotubular nephropathy

    Science.gov (United States)

    Gee, Heon Yung; Sadowski, Carolin E.; Aggarwal, Pardeep K.; Porath, Jonathan D.; Yakulov, Toma A.; Schueler, Markus; Lovric, Svjetlana; Ashraf, Shazia; Braun, Daniela A.; Halbritter, Jan; Fang, Humphrey; Airik, Rannar; Vega-Warner, Virginia; Cho, Kyeong Jee; Chan, Timothy A.; Morris, Luc G. T.; ffrench-Constant, Charles; Allen, Nicholas; McNeill, Helen; Büscher, Rainer; Kyrieleis, Henriette; Wallot, Michael; Gaspert, Ariana; Kistler, Thomas; Milford, David V.; Saleem, Moin A.; Keng, Wee Teik; Alexander, Stephen I.; Valentini, Rudolph P.; Licht, Christoph; Teh, Jun C.; Bogdanovic, Radovan; Koziell, Ania; Bierzynska, Agnieszka; Soliman, Neveen A.; Otto, Edgar A.; Lifton, Richard P.; Holzman, Lawrence B.; Sibinga, Nicholas E. S.; Walz, Gerd; Tufro, Alda; Hildebrandt, Friedhelm

    2016-01-01

    Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease (CKD). Here we show that recessive mutations in FAT1 cause a distinct renal disease entity in four families with a combination of SRNS, tubular ectasia, haematuria and facultative neurological involvement. Loss of FAT1 results in decreased cell adhesion and migration in fibroblasts and podocytes and the decreased migration is partially reversed by a RAC1/CDC42 activator. Podocyte-specific deletion of Fat1 in mice induces abnormal glomerular filtration barrier development, leading to podocyte foot process effacement. Knockdown of Fat1 in renal tubular cells reduces migration, decreases active RAC1 and CDC42, and induces defects in lumen formation. Knockdown of fat1 in zebrafish causes pronephric cysts, which is partially rescued by RAC1/CDC42 activators, confirming a role of the two small GTPases in the pathogenesis. These findings provide new insights into the pathogenesis of SRNS and tubulopathy, linking FAT1 and RAC1/CDC42 to podocyte and tubular cell function. PMID:26905694

  18. Phenotypic and genetic analysis of the cerebellar mutant tmgc26, a new ENU-induced ROR-alpha allele.

    Science.gov (United States)

    Swanson, Douglas J; Steshina, Ekaterina Y; Wakenight, Paul; Aldinger, Kimberly A; Goldowitz, Dan; Millen, Kathleen J; Chizhikov, Victor V

    2010-09-01

    ROR-alpha is an orphan nuclear receptor, inactivation of which cell-autonomously blocks differentiation of cerebellar Purkinje cells with a secondary loss of granule neurons. As part of our ENU mutagenesis screen we isolated the recessive tmgc26 mouse mutant, characterized by early-onset progressive ataxia, cerebellar degeneration and juvenile lethality. Detailed analysis of the tmgc26-/- cerebella revealed Purkinje cell and granule cell abnormalities, and defects in molecular layer interneurons and radial glia. Chimera studies suggested a cell-autonomous effect of the tmgc26 mutation in Purkinje cells and molecular layer interneurons, and a non-cell-autonomous effect in granule cells. The mutation was mapped to a 13-Mb interval on chromosome 9, a region that contains the ROR-alpha gene. Sequencing of genomic DNA revealed a T-to-A transition in exon 5 of the ROR-alpha gene, resulting in a nonsense mutation C257X and severe truncation of the ROR-alpha protein. Together, our data identify new roles for ROR-alpha in molecular layer interneurons and radial glia development and suggest tmgc26 as a novel ROR-alpha allele that may be used to further delineate the molecular mechanisms of ROR-alpha action. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  19. Analysis of mutations causing familial hypercholesterolaemia in ...

    African Journals Online (AJOL)

    High-resolution melting (HRM) and polymerase chain reaction (PCR). The promoter (up to position –298) and coding regions of the LDLR gene together with the p.(R3527Q) mutation (part of exon 26) of APOB and p.(D374Y) (exon 7) of the PCSK9 gene were screened by HRM. Designed oligonucleotide primers for ...

  20. 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....

  1. ELOVL5 Mutations Cause Spinocerebellar Ataxia 38

    Science.gov (United States)

    Di Gregorio, Eleonora; Borroni, Barbara; Giorgio, Elisa; Lacerenza, Daniela; Ferrero, Marta; Lo Buono, Nicola; Ragusa, Neftj; Mancini, Cecilia; Gaussen, Marion; Calcia, Alessandro; Mitro, Nico; Hoxha, Eriola; Mura, Isabella; Coviello, Domenico A.; Moon, Young-Ah; Tesson, Christelle; Vaula, Giovanna; Couarch, Philippe; Orsi, Laura; Duregon, Eleonora; Papotti, Mauro Giulio; Deleuze, Jean-François; Imbert, Jean; Costanzi, Chiara; Padovani, Alessandro; Giunti, Paola; Maillet-Vioud, Marcel; Durr, Alexandra; Brice, Alexis; Tempia, Filippo; Funaro, Ada; Boccone, Loredana; Caruso, Donatella; Stevanin, Giovanni; Brusco, Alfredo

    2014-01-01

    Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal-dominant neurodegenerative disorders involving the cerebellum and 23 different genes. We mapped SCA38 to a 56 Mb region on chromosome 6p in a SCA-affected Italian family by whole-genome linkage analysis. Targeted resequencing identified a single missense mutation (c.689G>T [p.Gly230Val]) in ELOVL5. Mutation screening of 456 independent SCA-affected individuals identified the same mutation in two further unrelated Italian families. Haplotyping showed that at least two of the three families shared a common ancestor. One further missense variant (c.214C>G [p.Leu72Val]) was found in a French family. Both missense changes affect conserved amino acids, are predicted to be damaging by multiple bioinformatics tools, and were not identified in ethnically matched controls or within variant databases. ELOVL5 encodes an elongase involved in the synthesis of polyunsaturated fatty acids of the ω3 and ω6 series. Arachidonic acid and docosahexaenoic acid, two final products of the enzyme, were reduced in the serum of affected individuals. Immunohistochemistry on control mice and human brain demonstrated high levels in Purkinje cells. In transfection experiments, subcellular localization of altered ELOVL5 showed a perinuclear distribution with a signal increase in the Golgi compartment, whereas the wild-type showed a widespread signal in the endoplasmic reticulum. SCA38 and SCA34 are examples of SCAs due to mutations in elongase-encoding genes, emphasizing the importance of fatty-acid metabolism in neurological diseases. PMID:25065913

  2. Equine diseases caused by known genetic mutations.

    Science.gov (United States)

    Finno, Carrie J; Spier, Sharon J; Valberg, Stephanie J

    2009-03-01

    The recent development of equine genome maps by the equine genome community and the complete sequencing of the horse genome performed at the Broad Institute have accelerated the pace of genetic discovery. This review focuses on genetic diseases in the horse for which a mutation is currently known, including hyperkalemic periodic paralysis, severe combined immunodeficiency, overo lethal white syndrome, junctional epidermolysis bullosa, glycogen branching enzyme deficiency, malignant hyperthermia, hereditary equine regional dermal asthenia, and polysaccharide storage myopathy. Emphasis is placed on the prevalence, clinical signs, etiology, diagnosis, treatment and prognosis for each disease.

  3. Mutations in RNF216 do not cause 4H syndrome

    NARCIS (Netherlands)

    Wolf, N.I.; Bernard, G.

    2015-01-01

    We comment on the recent publication by Ganos et al. [1] classifying a patient with non-specific white matter abnormalities, cerebellar atrophy, hypogonadotropic hypogonadism and absent lower median incisors as 4H syndrome. He had mutations in RNF216. Mutations in this gene cause Gordon-Holmes

  4. Hereditary spastic paraplegia caused by the PLP1 'rumpshaker mutation'

    DEFF Research Database (Denmark)

    Svenstrup, Kirsten; Giraud, Geneviève; Boespflug-Tanguy, Odile

    2010-01-01

    with the 'rumpshaker mutation.' PATIENTS: A family with HSP caused by the 'rumpshaker mutation.' RESULTS: The patients showed nystagmus during infancy and had early onset of HSP. They had normal cognition, and cerebral MRI showed relatively unspecific white matter abnormalities on T2 sequences without clear...

  5. 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...

  6. A restricted spectrum of NRAS mutations causes Noonan syndrome

    NARCIS (Netherlands)

    Cirstea, Ion C.; Kutsche, Kerstin; Dvorsky, Radovan; Gremer, Lothar; Carta, Claudio; Horn, Denise; Roberts, Amy E.; Lepri, Francesca; Merbitz-Zahradnik, Torsten; Koenig, Rainer; Kratz, Christian P.; Pantaleoni, Francesca; Dentici, Maria L.; Joshi, Victoria A.; Kucherlapati, Raju S.; Mazzanti, Laura; Mundlos, Stefan; Patton, Michael A.; Silengo, Margherita Cirillo; Rossi, Cesare; Zampino, Giuseppe; Digilio, Cristina; Stuppia, Liborio; Seemanova, Eva; Pennacchio, Len A.; Gelb, Bruce D.; Dallapiccola, Bruno; Wittinghofer, Alfred; Ahmadian, Mohammad R.; Tartaglia, Marco; Zenker, Martin

    Noonan syndrome, a developmental disorder characterized by congenital heart defects, reduced growth, facial dysmorphism and variable cognitive deficits, is caused by constitutional dysregulation of the RAS-MAPK signaling pathway. Here we report that germline NRAS mutations conferring enhanced

  7. Intersex (ix) mutations of Drosophila melanogaster cause ...

    Indian Academy of Sciences (India)

    Stock Center, USA). dpp stocks: The following four dpp stocks were used in the present investigation: (i) dppdho/SM5 (Blackman et al. 1991). 'heldout' is the mildest allele of the disk region which causes defective only in wing posture, (ii) dppd5/CyO, class dII of dpp allele exhibit reduction of male genitalia in homozygous.

  8. Novel allelic mutations in murine Serca2 induce differential development of squamous cell tumors

    Energy Technology Data Exchange (ETDEWEB)

    Toki, Hideaki; Minowa, Osamu; Inoue, Maki; Motegi, Hiromi; Karashima, Yuko; Ikeda, Ami [Team for Advanced Development and Evaluation of Human Disease Models, Riken BioResource Center (BRC), Tsukuba, Ibaraki (Japan); Kaneda, Hideki [Technology and Development Team for Mouse Phenotype Analysis, Riken BRC, Tsukuba, Ibaraki (Japan); Sakuraba, Yoshiyuki [Mutagenesis and Genomics Team, Riken BRC, Tsukuba, Ibaraki (Japan); Saiki, Yuriko [Department of Molecular Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi (Japan); Wakana, Shigeharu [Technology and Development Team for Mouse Phenotype Analysis, Riken BRC, Tsukuba, Ibaraki (Japan); Suzuki, Hiroshi [Department of Biochemistry, Asahikawa Medical University, Asahikawa, Hokkaido (Japan); Gondo, Yoichi [Mutagenesis and Genomics Team, Riken BRC, Tsukuba, Ibaraki (Japan); Shiroishi, Toshihiko [Mammalian Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka (Japan); Noda, Tetsuo, E-mail: tnoda@jfcr.or.jp [Team for Advanced Development and Evaluation of Human Disease Models, Riken BioResource Center (BRC), Tsukuba, Ibaraki (Japan); Department of Cell Biology, Cancer Institute, The Japanese Foundation for Cancer Research, Tokyo (Japan)

    2016-08-05

    Dominant mutations in the Serca2 gene, which encodes sarco(endo)plasmic reticulum calcium-ATPase, predispose mice to gastrointestinal epithelial carcinoma [1–4] and humans to Darier disease (DD) [14–17]. In this study, we generated mice harboring N-ethyl-N-nitrosourea (ENU)-induced allelic mutations in Serca2: three missense mutations and one nonsense mutation. Mice harboring these Serca2 mutations developed tumors that were categorized as either early onset squamous cell tumors (SCT), with development similar to null-type knockout mice [2,4] (aggressive form; M682, M814), or late onset tumors (mild form; M1049, M1162). Molecular analysis showed no aberration in Serca2 mRNA or protein expression levels in normal esophageal cells of any of the four mutant heterozygotes. There was no loss of heterozygosity at the Serca2 locus in the squamous cell carcinomas in any of the four lines. The effect of each mutation on Ca{sup 2+}-ATPase activity was predicted using atomic-structure models and accumulated mutated protein studies, suggesting that putative complete loss of Serca2 enzymatic activity may lead to early tumor onset, whereas mutations in which Serca2 retains residual enzymatic activity result in late onset. We propose that impaired Serca2 gene product activity has a long-term effect on squamous cell carcinogenesis from onset to the final carcinoma stage through an as-yet unrecognized but common regulatory pathway. -- Highlights: •Novel mutations in murine Serca2 caused early onset or late onset of tumorigenesis. •They also caused higher or lower incidence of Darier Disease phenotype. •3D structure model suggested the former mutations led to severer defect on ATPase. •Driver gene mutations via long-range effect on Ca2+ distributions are suggested.

  9. A novel mutation in GATA6 causes pancreatic agenesis.

    Science.gov (United States)

    Stanescu, Diana E; Hughes, Nkecha; Patel, Puja; De León, Diva D

    2015-02-01

    Heterozygous mutations in GATA6 have been linked to pancreatic agenesis and cardiac malformations. The aim of this study was to describe a new mutation in GATA6 in an infant with pancreatic agenesis, associated with truncus arteriosus and absent gallbladder. Clinical data were obtained from chart review. Gene sequencing was performed on genomic DNA. The patient was a female infant diagnosed shortly after birth with a severe cardiac malformation, absent gallbladder, anomalous hepatic blood flow, unilateral hydronephrosis and hydroureter, neonatal diabetes, and pancreatic exocrine insufficiency. Despite prolonged intensive management care, she died at 3 months of age because of cardiac complications. Analysis of her genomic DNA revealed a novel missense mutation of GATA6. The novel mutation described in this case extends the list of GATA6 mutations causing pancreatic agenesis and cardiac malformations. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Dominant cataract mutations and specific-locus mutations in mice induced by radiation or ethylnitrosourea

    International Nuclear Information System (INIS)

    Ehling, U.H.; Favor, J.; Kratochvilova, J.; Neuhaeuser-Klaus, A.

    1982-01-01

    In a combined experiment, dominant cataract mutations and specific-locus mutations were scored in the same offspring. In radiation experiments, a total of 15 dominant cataract and 38 specific-locus mutations was scored in 29396 offspring. In experiments with ethylnitrosourea (ENU), a total of 12 dominant cataracts and 54 specific-locus mutations was observed in 12712 offspring. The control frequency for dominant cataracts was 0 in 9954 offspring and for specific-locus mutations 11 in 169955 offspring. The two characteristic features of radiation-induced specific-locus mutations - the augmenting effect of dose fractionation and the quantitative differences in the mutation rates between spermatogonial and post-spermatogonial stages - can also be demonstrated for the induction of dominant cataracts. The dominant cataract mutations recovered can be categorized into 7 phenotypic classes. The only noteworthy difference observed between the radiation- and ENU-induced mutations recovered was that, of the 2 radiation-induced total lens opacities, both were associated with an iris anomaly and microphthalmia whereas the ENU-induced total opacities were not. (orig./MG)

  11. A nonsense mutation in FMR1 causing fragile X syndrome

    DEFF Research Database (Denmark)

    Grønskov, Karen; Brøndum-Nielsen, Karen; Dedic, Alma

    2011-01-01

    Fragile X syndrome is a common cause of inherited intellectual disability. It is caused by lack of the FMR1 gene product FMRP. The most frequent cause is the expansion of a CGG repeat located in the 5'UTR of FMR1. Alleles with 200 or more repeats become hypermethylated and transcriptionally silent....... Only few patients with intragenic point mutations in FMR1 have been reported and, currently, routine analysis of patients referred for fragile X syndrome includes solely analysis for repeat expansion and methylation status. We identified a substitution in exon 2 of FMR1, c.80C>A, causing a nonsense...... mutation p.Ser27X, in a patient with classical clinical symptoms of fragile X syndrome. The mother who carried the mutation in heterozygous form presented with mild intellectual impairment. We conclude that further studies including western blot and DNA sequence analysis of the FMR1 gene should...

  12. A DSPP Mutation Causing Dentinogenesis Imperfecta and Characterization of the Mutational Effect

    Directory of Open Access Journals (Sweden)

    Sook-Kyung Lee

    2013-01-01

    Full Text Available Mutations in the DSPP gene have been identified in nonsyndromic hereditary dentin defects, but the genotype-phenotype correlations are not fully understood. Recently, it has been demonstrated that the mutations of DSPP affecting the IPV leader sequence result in mutant DSPP retention in rough endoplasmic reticulum (ER. In this study, we identified a Korean family with dentinogenesis imperfecta type III. To identify the disease causing mutation in this family, we performed mutational analysis based on candidate gene sequencing. Exons and exon-intron boundaries of DSPP gene were sequenced, and the effects of the identified mutation on the pre-mRNA splicing and protein secretion were investigated. Candidate gene sequencing revealed a mutation (c.50C > T, p.P17L in exon 2 of the DSPP gene. The splicing assay showed that the mutation did not influence pre-mRNA splicing. However, the mutation interfered with protein secretion and resulted in the mutant protein remaining largely in the ER. These results suggest that the mutation affects ER-to-Golgi apparatus export and results in the reduction of secreted DSPP and ER overload. This may induce cell stress and damage processing and/or transport of dentin matrix proteins or other critical proteins.

  13. Novel GABRG2 mutations cause familial febrile seizures

    Science.gov (United States)

    Boillot, Morgane; Morin-Brureau, Mélanie; Picard, Fabienne; Weckhuysen, Sarah; Lambrecq, Virginie; Minetti, Carlo; Striano, Pasquale; Zara, Federico; Iacomino, Michele; Ishida, Saeko; An-Gourfinkel, Isabelle; Daniau, Mailys; Hardies, Katia; Baulac, Michel; Dulac, Olivier; Leguern, Eric; Nabbout, Rima

    2015-01-01

    Objective: To identify the genetic cause in a large family with febrile seizures (FS) and temporal lobe epilepsy (TLE) and subsequently search for additional mutations in a cohort of 107 families with FS, with or without epilepsy. Methods: The cohort consisted of 1 large family with FS and TLE, 64 smaller French families recruited through a national French campaign, and 43 Italian families. Molecular analyses consisted of whole-exome sequencing and mutational screening. Results: Exome sequencing revealed a p.Glu402fs*3 mutation in the γ2 subunit of the GABAA receptor gene (GABRG2) in the large family with FS and TLE. Three additional nonsense and frameshift GABRG2 mutations (p.Arg136*, p.Val462fs*33, and p.Pro59fs*12), 1 missense mutation (p.Met199Val), and 1 exonic deletion were subsequently identified in 5 families of the follow-up cohort. Conclusions: We report GABRG2 mutations in 5.6% (6/108) of families with FS, with or without associated epilepsy. This study provides evidence that GABRG2 mutations are linked to the FS phenotype, rather than epilepsy, and that loss-of-function of GABAA receptor γ2 subunit is the probable underlying pathogenic mechanism. PMID:27066572

  14. A novel mutation of the fibrillin gene causing Ectopia lentis

    Energy Technology Data Exchange (ETDEWEB)

    Loennqvist, L.; Kainulainen, K.; Puhakka, L.; Peltonen, L. (National Public Health Institute, Helsinki (Finland)); Child, A. (St. George' s Hospital Medical School, London (United Kingdom)); Peltonen, L. (Duncan Guthrie Institute, Glasgow, Scotland (United Kingdom))

    1994-02-01

    Ectopia lentis (EL), a dominantly inherited connective tissue disorder, has been genetically linked to the fibrillin gene on chromosome 15 (FBN1) in earlier studies. Here, the authors report the first EL mutation in the FBN1 gene confirming that EL is caused by mutations of this gene. So far, several mutations in the FBN1 gene have been reported in patients with Marfan syndrome (MFS). EL and MFS are clinically related but distinct conditions with typical manifestations in the ocular and skeletal systems, the fundamental difference between them being the absence of cardiovascular involvement in EL. They report a point mutation, cosegregating with the disease in the described family, that displays EL over four generations. The mutation changes a conserved glutamic acid residue in an EGF-like motif, which is the major structural component of the fibrillin and is repeated throughout the polypeptide. In vitro mutagenetic studies have demonstrated the necessity of an analogous glutamic acid residue for calcium binding in an EGF-like repeat of human factor IX. This provides a possible explanation for the role of this mutation in the disease pathogenesis. 32 refs., 2 figs., 1 tab.

  15. Mutations in the pericentrin (PCNT) gene cause primordial dwarfism

    NARCIS (Netherlands)

    Rauch, Anita; Thiel, Christian T.; Schindler, Detlev; Wick, Ursula; Crow, Yanick J.; Ekici, Arif B.; van Essen, Anthonie J.; Goecke, Timm O.; Al-Gazali, Lihadh; Chrzanowska, Krystyna H.; Zweier, Christiane; Brunner, Han G.; Becker, Kristin; Curry, Cynthia J.; Dallapiccola, Bruno; Devriendt, Koenraad; Dörfler, Arnd; Kinning, Esther; Megarbane, André; Meinecke, Peter; Semple, Robert K.; Spranger, Stephanie; Toutain, Annick; Trembath, Richard C.; Voss, Egbert; Wilson, Louise; Hennekam, Raoul; de Zegher, Francis; Dörr, Helmuth-Günther; Reis, André

    2008-01-01

    Fundamental processes influencing human growth can be revealed by studying extreme short stature. Using genetic linkage analysis, we find that biallelic loss-of-function mutations in the centrosomal pericentrin (PCNT) gene on chromosome 21q22.3 cause microcephalic osteodysplastic primordial dwarfism

  16. Mutations in the pericentrin (PCNT) gene cause primordial dwarfism

    NARCIS (Netherlands)

    Rauch, Anita; Thiel, Christian T.; Schindler, Detlev; Wick, Ursula; Crow, Yanick J.; Ekici, Arif B.; van Essen, Anthonie J.; Goecke, Timm O.; Al-Gazali, Lihadh; Chrzanowska, Krystyna H.; Zweier, Christiane; Brunner, Han G.; Becker, Kristin; Curry, Cynthia J.; Dallapiccola, Bruno; Devriendt, Koenraad; Doerfler, Arnd; Kinning, Esther; Megarbane, Andre; Meinecke, Peter; Semple, Robert K.; Spranger, Stephanie; Toutain, Annick; Trembath, Richard C.; Voss, Egbert; Wilson, Louise; Hennekam, Raoul; de Zegher, Francis; Doerr, Helmuth-Guenther; Reis, Andre

    2008-01-01

    Fundamental processes influencing human growth can be revealed by studying extreme short stature. Using genetic linkage analysis, we find that biallelic loss- of- function mutations in the centrosomal pericentrin ( PCNT) gene on chromosome 21q22.3 cause microcephalic osteodysplastic primordial

  17. Mutations found in the Danish population causing Hereditary Hemorrhagic Telangiectasia

    DEFF Research Database (Denmark)

    Tørring, Pernille M; Brusgaard, Klaus

    2011-01-01

    University Hospital, Denmark HHT is an autosomal vascular disorder caused by mutations of either of three loci ENG, ACVLR1 or MADH4. HHT is characterised by recurrent nosebleeds, mucocutaneous telangiectases, and more severe visceral malformations. During the last decade the Danish HHT centre has...

  18. Familial gigantism caused by an NSD1 mutation.

    NARCIS (Netherlands)

    Haelst, M.M. van; Hoogeboom, J.J.; Baujat, G.; Bruggenwirth, H.T.; Laar, I. van de; Coleman, K.; Rahman, N.; Niermeijer, M.F.; Drop, S.L.; Scambler, P.J.

    2005-01-01

    A three-generation family with autosomal dominant segregation of a novel NSD1 mutation (6605G --> A, resulting in Cys2202Tyr) is reported. Haploinsufficiency of NSD1 has been identified as the major cause of Sotos syndrome. The overgrowth condition (MIM 117550) is characterized by facial anomalies,

  19. Splicing aberrations caused by constitutional RB1 gene mutations in ...

    Indian Academy of Sciences (India)

    . [Parsam VL, Ali MJ, Honavar SG, Vemuganti GK and Kannabiran C 2011 Splicing aberrations caused by constitutional RB1 gene mutations in retinoblastoma. J. Biosci. 36 281–287] DOI 10.1007/s12038-011-9062-9. 1. Introduction.

  20. A novel mutation in the AGXT gene causing primary hyperoxaluria ...

    Indian Academy of Sciences (India)

    A novel mutation in the AGXT gene causing primary hyperoxaluria type I: genotype–phenotype correlation. SAOUSSEN M'DIMEGH CÉCILE AQUAVIVA- BOURDAIN ASMA OMEZZINE IBTIHEL M'BAREK GENEVIÉVE SOUCHE DORSAF ZELLAMA KAMEL ABIDI ABDELATTIF ACHOUR TAHAR GARGAH SAOUSSEN ...

  1. A new amyloidosis caused by fibrillar aggregates of mutated corneodesmosin

    DEFF Research Database (Denmark)

    Caubet, Cécile; Bousset, Luc; Clemmensen, Ole

    2010-01-01

    Heterozygous nonsense mutations in the CDSN gene encoding corneodesmosin (CDSN), an adhesive protein expressed in cornified epithelia and hair follicles, cause hypotrichosis simplex of the scalp (HSS), a nonsyndromic form of alopecia. Truncated mutants of CDSN ((mut)CDSN), which bear the N...

  2. Potassium channel gene mutations rarely cause atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Nam Edwin G

    2006-08-01

    Full Text Available Abstract Background Mutations in several potassium channel subunits have been associated with rare forms of atrial fibrillation. In order to explore the role of potassium channels in inherited typical forms of the arrhythmia, we have screened a cohort of patients from a referral clinic for mutations in the channel subunit genes implicated in the arrhythmia. We sought to determine if mutations in KCNJ2 and KCNE1-5 are a common cause of atrial fibrillation. Methods Serial patients with lone atrial fibrillation or atrial fibrillation with hypertension were enrolled between June 1, 2001 and January 6, 2005. Each patient underwent a standardized interview and physical examination. An electrocardiogram, echocardiogram and blood sample for genetic analysis were also obtained. Patients with a family history of AF were screened for mutations in KCNJ2 and KCNE1-5 using automated sequencing. Results 96 patients with familial atrial fibrillation were enrolled. Eighty-three patients had lone atrial fibrillation and 13 had atrial fibrillation and hypertension. Patients had a mean age of 56 years at enrollment and 46 years at onset of atrial fibrillation. Eighty-one percent of patients had paroxysmal atrial fibrillation at enrollment. Unlike patients with an activating mutation in KCNQ1, the patients had a normal QTc interval with a mean of 412 ± 42 ms. Echocardiography revealed a normal mean ejection fraction of 62.0 ± 7.2 % and mean left atrial dimension of 39.9 ± 7.0 mm. A number of common polymorphisms in KCNJ2 and KCNE1-5 were identified, but no mutations were detected. Conclusion Mutations in KCNJ2 and KCNE1-5 rarely cause typical atrial fibrillation in a referral clinic population.

  3. Dominant de novo DSP mutations cause erythrokeratodermia-cardiomyopathy syndrome.

    Science.gov (United States)

    Boyden, Lynn M; Kam, Chen Y; Hernández-Martín, Angela; Zhou, Jing; Craiglow, Brittany G; Sidbury, Robert; Mathes, Erin F; Maguiness, Sheilagh M; Crumrine, Debra A; Williams, Mary L; Hu, Ronghua; Lifton, Richard P; Elias, Peter M; Green, Kathleen J; Choate, Keith A

    2016-01-15

    Disorders of keratinization (DOK) show marked genotypic and phenotypic heterogeneity. In most cases, disease is primarily cutaneous, and further clinical evaluation is therefore rarely pursued. We have identified subjects with a novel DOK featuring erythrokeratodermia and initially-asymptomatic, progressive, potentially fatal cardiomyopathy, a finding not previously associated with erythrokeratodermia. We show that de novo missense mutations clustered tightly within a single spectrin repeat of DSP cause this novel cardio-cutaneous disorder, which we term erythrokeratodermia-cardiomyopathy (EKC) syndrome. We demonstrate that DSP mutations in our EKC syndrome subjects affect localization of desmosomal proteins and connexin 43 in the skin, and result in desmosome aggregation, widening of intercellular spaces, and lipid secretory defects. DSP encodes desmoplakin, a primary component of desmosomes, intercellular adhesion junctions most abundant in the epidermis and heart. Though mutations in DSP are known to cause other disorders, our cohort features the unique clinical finding of severe whole-body erythrokeratodermia, with distinct effects on localization of desmosomal proteins and connexin 43. These findings add a severe, previously undescribed syndrome featuring erythrokeratodermia and cardiomyopathy to the spectrum of disease caused by mutation in DSP, and identify a specific region of the protein critical to the pathobiology of EKC syndrome and to DSP function in the heart and skin. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. CD48-deficient T-lymphocytes from DMBA-treated rats have de novo mutations in the endogenous Pig-a gene.

    Science.gov (United States)

    Dobrovolsky, Vasily N; Revollo, Javier; Pearce, Mason G; Pacheco-Martinez, M Monserrat; Lin, Haixia

    2015-10-01

    A major question concerning the scientific and regulatory acceptance of the rodent red blood cell-based Pig-a gene mutation assay is the extent to which mutants identified by their phenotype in the assay are caused by mutations in the Pig-a gene. In this study, we identified T-lymphocytes deficient for the glycosylphosphatidylinositol-anchored surface marker, CD48, in control and 7,12-dimethylbenz[a]anthracene (DMBA)-treated rats using a flow cytometric assay and determined the spectra of mutations in the endogenous Pig-a gene in these cells. CD48-deficient T-cells were seeded by sorting at one cell per well into 96-well plates, expanded into clones, and exons of their genomic Pig-a were sequenced. The majority (78%) of CD48-deficient T-cell clones from DMBA-treated rats had mutations in the Pig-a gene. The spectrum of DMBA-induced Pig-a mutations was dominated by mutations at A:T, with the mutated A being on the nontranscribed strand and A → T transversion being the most frequent change. The spectrum of Pig-a mutations in DMBA-treated rats was different from the spectrum of Pig-a mutations in N-ethyl-N-nitrosourea (ENU)-treated rats, but similar to the spectrum of DMBA mutations for another endogenous X-linked gene, Hprt. Only 15% of CD48-deficient mutants from control animals contained Pig-a mutations; T-cell biology may be responsible for a relatively large fraction of false Pig-a mutant lymphocytes in control animals. Among the verified mutants from control rats, the most common were frameshifts and deletions. The differences in the spectra of spontaneous, DMBA-, and ENU-induced Pig-a mutations suggest that the flow cytometric Pig-a assay detects de novo mutation in the endogenous Pig-a gene. © 2015 Wiley Periodicals, Inc.

  5. Hot-spot KIF5A mutations cause familial ALS

    Science.gov (United States)

    Yilmaz, Rüstem; Müller, Kathrin; Grehl, Torsten; Petri, Susanne; Meyer, Thomas; Grosskreutz, Julian; Weydt, Patrick; Ruf, Wolfgang; Neuwirth, Christoph; Weber, Markus; Pinto, Susana; Claeys, Kristl G; Schrank, Berthold; Jordan, Berit; Knehr, Antje; Günther, Kornelia; Hübers, Annemarie; Zeller, Daniel; Kubisch, Christian; Jablonka, Sibylle; Klopstock, Thomas; de Carvalho, Mamede; Sperfeld, Anne; Borck, Guntram; Volk, Alexander E; Dorst, Johannes; Weis, Joachim; Otto, Markus; Schuster, Joachim; Del Tredici, Kelly; Braak, Heiko; Danzer, Karin M; Freischmidt, Axel; Meitinger, Thomas; Strom, Tim M; Ludolph, Albert C; Andersen, Peter M; Weishaupt, Jochen H; Weyen, Ute; Hermann, Andreas; Hagenacker, Tim; Koch, Jan Christoph; Lingor, Paul; Göricke, Bettina; Zierz, Stephan; Baum, Petra; Wolf, Joachim; Winkler, Andrea; Young, Peter; Bogdahn, Ulrich; Prudlo, Johannes; Kassubek., Jan

    2018-01-01

    Abstract Heterozygous missense mutations in the N-terminal motor or coiled-coil domains of the kinesin family member 5A (KIF5A) gene cause monogenic spastic paraplegia (HSP10) and Charcot-Marie-Tooth disease type 2 (CMT2). Moreover, heterozygous de novo frame-shift mutations in the C-terminal domain of KIF5A are associated with neonatal intractable myoclonus, a neurodevelopmental syndrome. These findings, together with the observation that many of the disease genes associated with amyotrophic lateral sclerosis disrupt cytoskeletal function and intracellular transport, led us to hypothesize that mutations in KIF5A are also a cause of amyotrophic lateral sclerosis. Using whole exome sequencing followed by rare variant analysis of 426 patients with familial amyotrophic lateral sclerosis and 6137 control subjects, we detected an enrichment of KIF5A splice-site mutations in amyotrophic lateral sclerosis (2/426 compared to 0/6137 in controls; P = 4.2 × 10−3), both located in a hot-spot in the C-terminus of the protein and predicted to affect splicing exon 27. We additionally show co-segregation with amyotrophic lateral sclerosis of two canonical splice-site mutations in two families. Investigation of lymphoblast cell lines from patients with KIF5A splice-site mutations revealed the loss of mutant RNA expression and suggested haploinsufficiency as the most probable underlying molecular mechanism. Furthermore, mRNA sequencing of a rare non-synonymous missense mutation (predicting p.Arg1007Gly) located in the C-terminus of the protein shortly upstream of the splice donor of exon 27 revealed defective KIF5A pre-mRNA splicing in respective patient-derived cell lines owing to abrogation of the donor site. Finally, the non-synonymous single nucleotide variant rs113247976 (minor allele frequency = 1.00% in controls, n = 6137), also located in the C-terminal region [p.(Pro986Leu) in exon 26], was significantly enriched in familial amyotrophic lateral sclerosis patients (minor

  6. Homozygous STIL mutation causes holoprosencephaly and microcephaly in two siblings.

    Directory of Open Access Journals (Sweden)

    Charlotte Mouden

    Full Text Available Holoprosencephaly (HPE is a frequent congenital malformation of the brain characterized by impaired forebrain cleavage and midline facial anomalies. Heterozygous mutations in 14 genes have been identified in HPE patients that account for only 30% of HPE cases, suggesting the existence of other HPE genes. Data from homozygosity mapping and whole-exome sequencing in a consanguineous Turkish family were combined to identify a homozygous missense mutation (c.2150G>A; p.Gly717Glu in STIL, common to the two affected children. STIL has a role in centriole formation and has previously been described in rare cases of microcephaly. Rescue experiments in U2OS cells showed that the STIL p.Gly717Glu mutation was not able to fully restore the centriole duplication failure following depletion of endogenous STIL protein indicating the deleterious role of the mutation. In situ hybridization experiments using chick embryos demonstrated that expression of Stil was in accordance with a function during early patterning of the forebrain. It is only the second time that a STIL homozygous mutation causing a recessive form of HPE was reported. This result also supports the genetic heterogeneity of HPE and increases the panel of genes to be tested for HPE diagnosis.

  7. De Novo Mutations in EBF3 Cause a Neurodevelopmental Syndrome.

    Science.gov (United States)

    Sleven, Hannah; Welsh, Seth J; Yu, Jing; Churchill, Mair E A; Wright, Caroline F; Henderson, Alex; Horvath, Rita; Rankin, Julia; Vogt, Julie; Magee, Alex; McConnell, Vivienne; Green, Andrew; King, Mary D; Cox, Helen; Armstrong, Linlea; Lehman, Anna; Nelson, Tanya N; Williams, Jonathan; Clouston, Penny; Hagman, James; Németh, Andrea H

    2017-01-05

    Early B cell factor 3 (EBF3) is an atypical transcription factor that is thought to influence the laminar formation of the cerebral cortex. Here, we report that de novo mutations in EBF3 cause a complex neurodevelopmental syndrome. The mutations were identified in two large-scale sequencing projects: the UK Deciphering Developmental Disorders (DDD) study and the Canadian Clinical Assessment of the Utility of Sequencing and Evaluation as a Service (CAUSES) study. The core phenotype includes moderate to severe intellectual disability, and many individuals exhibit cerebellar ataxia, subtle facial dysmorphism, strabismus, and vesicoureteric reflux, suggesting that EBF3 has a widespread developmental role. Pathogenic de novo variants identified in EBF3 include multiple loss-of-function and missense mutations. Structural modeling suggested that the missense mutations affect DNA binding. Functional analysis of mutant proteins with missense substitutions revealed reduced transcriptional activities and abilities to form heterodimers with wild-type EBF3. We conclude that EBF3, a transcription factor previously unknown to be associated with human disease, is important for brain and other organ development and warrants further investigation. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  8. Somatic mutation, a cause of biliary atresia: A hypothesis.

    Science.gov (United States)

    Fabre, Alexandre; Roman, Céline; Roquelaure, Bertrand

    2017-05-01

    Despite many years of research, the causes of biliary atresia still remain elusive. Infection, immune disorder, toxins or maternal microchimerism have been cited as potential triggers of biliary atresia. This is a rare disease with a stable incidence over the years although with sizeable ethnic variations. This stability suggests that environmental factors have in fact only a slight influence. During the search for etiologies, twin studies have often helped disentangle the genetic from the environmental. For this condition, twin studies have mainly demonstrated a lack of concordance between twins (either monozygotic or dizygotic), ruling out Mendelian, infectious or toxic causes. Indeed, for toxic or infectious embryopathy, the concordance for twins (especially monozygotic) is about 80%. Paradoxically, these data suggest that biliary atresia has neither a genetic nor an environmental cause. One way of severing the Gordian knot is to hypothesize a role for post zygotic somatic mutation, leading to genetic mosaicism (as a cause of biliary atresia). In recent years, post zygotic mutation has been identified as a cause of non-cancerous disease ranging from dysmorphic syndrome to specific organ abnormalities. A potential model for this condition could be post zygotic mutation or copy number variations in genes or regulatory regions, triggering the cascade of events leading to inflammatory and obliterative cholangiopathy. These events could be enhanced by genetic susceptibility explaining the ethnic variations. In these models, the rate of mosaicism in different parts of the liver could explain the success rate of the Kasai procedure. This hypothesis can be tested: as most children with biliary atresia are eligible for the Kasai procedure, genetic material from the liver and ductal plate can be collected easily. If the hypothesis is correct, whole genome sequencing or copy number variation studies at individual cell level should allow to identify the expected low level

  9. Mutations in calmodulin cause ventricular tachycardia and sudden cardiac death

    DEFF Research Database (Denmark)

    Nyegaard, Mette; Overgaard, Michael Toft; Sondergaard, M.T.

    2012-01-01

    Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a devastating inherited disorder characterized by episodic syncope and/or sudden cardiac arrest during exercise or acute emotion in individuals without structural cardiac abnormalities. Although rare, CPVT is suspected to cause...... a substantial part of sudden cardiac deaths in young individuals. Mutations in RYR2, encoding the cardiac sarcoplasmic calcium channel, have been identified as causative in approximately half of all dominantly inherited CPVT cases. Applying a genome-wide linkage analysis in a large Swedish family with a severe...... calmodulin-binding-domain peptide at low calcium concentrations. We conclude that calmodulin mutations can cause severe cardiac arrhythmia and that the calmodulin genes are candidates for genetic screening of individual cases and families with idiopathic ventricular tachycardia and unexplained sudden cardiac...

  10. Congenital myopathy is caused by mutation of HACD1.

    Science.gov (United States)

    Muhammad, Emad; Reish, Orit; Ohno, Yusuke; Scheetz, Todd; Deluca, Adam; Searby, Charles; Regev, Miriam; Benyamini, Lilach; Fellig, Yakov; Kihara, Akio; Sheffield, Val C; Parvari, Ruti

    2013-12-20

    Congenital myopathies are heterogeneous inherited diseases of muscle characterized by a range of distinctive histologic abnormalities. We have studied a consanguineous family with congenital myopathy. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous non-sense mutation in 3-hydroxyacyl-CoA dehydratase 1 (HACD1) in affected individuals. The mutation results in non-sense mediated decay of the HACD1 mRNA to 31% of control levels in patient muscle and completely abrogates the enzymatic activity of dehydration of 3-hydroxyacyl-CoA, the third step in the elongation of very long-chain fatty acids (VLCFAs). We describe clinical findings correlated with a deleterious mutation in a gene not previously known to be associated with congenital myopathy in humans. We suggest that the mutation in the HACD1 gene causes a reduction in the synthesis of VLCFAs, which are components of membrane lipids and participants in physiological processes, leading to congenital myopathy. These data indicate that HACD1 is necessary for muscle function.

  11. CSB-PGBD3 Mutations Cause Premature Ovarian Failure.

    Directory of Open Access Journals (Sweden)

    Yingying Qin

    2015-07-01

    Full Text Available Premature ovarian failure (POF is a rare, heterogeneous disorder characterized by cessation of menstruation occurring before the age of 40 years. Genetic etiology is responsible for perhaps 25% of cases, but most cases are sporadic and unexplained. In this study, through whole exome sequencing in a non-consanguineous family having four affected members with POF and Sanger sequencing in 432 sporadic cases, we identified three novel mutations in the fusion gene CSB-PGBD3. Subsequently functional studies suggest that mutated CSB-PGBD3 fusion protein was impaired in response to DNA damage, as indicated by delayed or absent recruitment to damaged sites. Our data provide the first evidence that mutations in the CSB-PGBD3 fusion protein can cause human disease, even in the presence of functional CSB, thus potentially explaining conservation of the fusion protein for 43 My since marmoset. The localization of the CSB-PGBD3 fusion protein to UVA-induced nuclear DNA repair foci further suggests that the CSB-PGBD3 fusion protein, like many other proteins that can cause POF, modulates or participates in DNA repair.

  12. Similar phenotypes caused by mutations in OTOG and OTOGL

    Science.gov (United States)

    Oonk, Anne M.M.; Leijendeckers, Joop M.; Huygen, Patrick L.M.; Schraders, Margit; del Campo, Miguel; del Castillo, Ignacio; Tekin, Mustafa; Feenstra, Ilse; Beynon, Andy J.; Kunst, Henricus P.M.; Snik, Ad F.M.; Kremer, Hannie; Admiraal, Ronald J.C.; Pennings, Ronald J.E.

    2013-01-01

    Objectives recently, OTOG and OTOGL were identified as human deafness genes. Currently, only four families are known to have autosomal recessive hearing loss based on mutations in these genes. Since the two genes code for proteins (otogelin and otogelin-like) that are strikingly similar in structure and localization in the inner ear, this study is focused on characterizing and comparing the hearing loss caused by mutations in these genes. Design To evaluate this type of hearing, an extensive set of audiometric and vestibular examinations was performed in the 13 patients from four families. Results all families show a flat to downsloping configuration of the audiogram with mild to moderate sensorineural hearing loss. Speech recognition scores remain good (>90%). Hearing loss is not significantly different in the four families and the psychophysical test results also do not differ between the families. Vestibular examinations show evidence for vestibular hyporeflexia. Conclusion since otogelin and otogelin-like are localized in the tectorial membrane, one could expect a cochlear conductive hearing loss, as was previously shown in DFNA13 (COL11A2) and DFNA8/12 (TECTA) patients. Results of psychophysical examinations, however, do not support this. Furthermore, the authors can conclude that there are no phenotypic differences between hearing loss based on mutations in OTOG or OTOGL. This phenotype description will facilitate counseling of hearing loss caused by defects in either of these two genes. PMID:24378291

  13. CtIP Mutations Cause Seckel and Jawad Syndromes.

    Directory of Open Access Journals (Sweden)

    Per Qvist

    2011-10-01

    Full Text Available Seckel syndrome is a recessively inherited dwarfism disorder characterized by microcephaly and a unique head profile. Genetically, it constitutes a heterogeneous condition, with several loci mapped (SCKL1-5 but only three disease genes identified: the ATR, CENPJ, and CEP152 genes that control cellular responses to DNA damage. We previously mapped a Seckel syndrome locus to chromosome 18p11.31-q11.2 (SCKL2. Here, we report two mutations in the CtIP (RBBP8 gene within this locus that result in expression of C-terminally truncated forms of CtIP. We propose that these mutations are the molecular cause of the disease observed in the previously described SCKL2 family and in an additional unrelated family diagnosed with a similar form of congenital microcephaly termed Jawad syndrome. While an exonic frameshift mutation was found in the Jawad family, the SCKL2 family carries a splicing mutation that yields a dominant-negative form of CtIP. Further characterization of cell lines derived from the SCKL2 family revealed defective DNA damage induced formation of single-stranded DNA, a critical co-factor for ATR activation. Accordingly, SCKL2 cells present a lowered apoptopic threshold and hypersensitivity to DNA damage. Notably, over-expression of a comparable truncated CtIP variant in non-Seckel cells recapitulates SCKL2 cellular phenotypes in a dose-dependent manner. This work thus identifies CtIP as a disease gene for Seckel and Jawad syndromes and defines a new type of genetic disease mechanism in which a dominant negative mutation yields a recessively inherited disorder.

  14. De novo SOX11 mutations cause Coffin-Siris syndrome.

    Science.gov (United States)

    Tsurusaki, Yoshinori; Koshimizu, Eriko; Ohashi, Hirofumi; Phadke, Shubha; Kou, Ikuyo; Shiina, Masaaki; Suzuki, Toshifumi; Okamoto, Nobuhiko; Imamura, Shintaro; Yamashita, Michiaki; Watanabe, Satoshi; Yoshiura, Koh-ichiro; Kodera, Hirofumi; Miyatake, Satoko; Nakashima, Mitsuko; Saitsu, Hirotomo; Ogata, Kazuhiro; Ikegawa, Shiro; Miyake, Noriko; Matsumoto, Naomichi

    2014-06-02

    Coffin-Siris syndrome (CSS) is a congenital disorder characterized by growth deficiency, intellectual disability, microcephaly, characteristic facial features and hypoplastic nails of the fifth fingers and/or toes. We previously identified mutations in five genes encoding subunits of the BAF complex, in 55% of CSS patients. Here we perform whole-exome sequencing in additional CSS patients, identifying de novo SOX11 mutations in two patients with a mild CSS phenotype. sox11a/b knockdown in zebrafish causes brain abnormalities, potentially explaining the brain phenotype of CSS. SOX11 is the downstream transcriptional factor of the PAX6-BAF complex, highlighting the importance of the BAF complex and SOX11 transcriptional network in brain development.

  15. Mutations of CEP83 Cause Infantile Nephronophthisis and Intellectual Disability

    Science.gov (United States)

    Failler, Marion; Gee, Heon Yung; Krug, Pauline; Joo, Kwangsic; Halbritter, Jan; Belkacem, Lilya; Filhol, Emilie; Porath, Jonathan D.; Braun, Daniela A.; Schueler, Markus; Frigo, Amandine; Alibeu, Olivier; Masson, Cécile; Brochard, Karine; Hurault de Ligny, Bruno; Novo, Robert; Pietrement, Christine; Kayserili, Hulya; Salomon, Rémi; Gubler, Marie-Claire; Otto, Edgar A.; Antignac, Corinne; Kim, Joon; Benmerah, Alexandre; Hildebrandt, Friedhelm; Saunier, Sophie

    2014-01-01

    Ciliopathies are a group of hereditary disorders associated with defects in cilia structure and function. The distal appendages (DAPs) of centrioles are involved in the docking and anchoring of the mother centriole to the cellular membrane during ciliogenesis. The molecular composition of DAPs was recently elucidated and mutations in two genes encoding DAPs components (CEP164/NPHP15, SCLT1) have been associated with human ciliopathies, namely nephronophthisis and orofaciodigital syndrome. To identify additional DAP components defective in ciliopathies, we independently performed targeted exon sequencing of 1,221 genes associated with cilia and 5 known DAP protein-encoding genes in 1,255 individuals with a nephronophthisis-related ciliopathy. We thereby detected biallelic mutations in a key component of DAP-encoding gene, CEP83, in seven families. All affected individuals had early-onset nephronophthisis and four out of eight displayed learning disability and/or hydrocephalus. Fibroblasts and tubular renal cells from affected individuals showed an altered DAP composition and ciliary defects. In summary, we have identified mutations in CEP83, another DAP-component-encoding gene, as a cause of infantile nephronophthisis associated with central nervous system abnormalities in half of the individuals. PMID:24882706

  16. Niemann-Pick type C mutations cause lipid traffic jam.

    Science.gov (United States)

    Liscum, L

    2000-03-01

    The Niemann-Pick C protein (NPC1) is required for cholesterol transport from late endosomes and lysosomes to other cellular membranes. Mutations in NPC1 cause lysosomal lipid storage and progressive neurological degeneration. Cloning of the NPC1 gene has given us tools with which to investigate the function of this putative cholesterol transporter. Here, we discuss recent studies indicating that NPC1 is not a cholesterol-specific transport molecule. Instead, NPC1 appears to be required for the vesicular shuttling of both lipids and fluid-phase constituents from multivesicular late endosomes to destinations such as the trans-Golgi network.

  17. A novel TRPC6 mutation that causes childhood FSGS.

    Directory of Open Access Journals (Sweden)

    Saskia F Heeringa

    2009-11-01

    Full Text Available TRPC6, encoding a member of the transient receptor potential (TRP superfamily of ion channels, is a calcium-permeable cation channel, which mediates capacitive calcium entry into the cell. Until today, seven different mutations in TRPC6 have been identified as a cause of autosomal-dominant focal segmental glomerulosclerosis (FSGS in adults.Here we report a novel TRPC6 mutation that leads to early onset FSGS. We identified one family in whom disease segregated with a novel TRPC6 mutation (M132T, that also affected pediatric individuals as early as nine years of age. Twenty-one pedigrees compatible with an autosomal-dominant mode of inheritance and biopsy-proven FSGS were selected from a worldwide cohort of 550 families with steroid resistant nephrotic syndrome (SRNS. Whole cell current recordings of the mutant TRPC6 channel, compared to the wild-type channel, showed a 3 to 5-fold increase in the average out- and inward TRPC6 current amplitude. The mean inward calcium current of M132T was 10-fold larger than that of wild-type TRPC6. Interestingly, M132T mutants also lacked time-dependent inactivation. Generation of a novel double mutant M132T/N143S did not further augment TRPC6 channel activity.In summary, our data shows that TRPC6 mediated FSGS can also be found in children. The large increase in channel currents and impaired channel inactivation caused by the M132T mutant leads to an aggressive phenotype that underlines the importance of calcium dose channeled through TRPC6.

  18. Mutations of TMC1 cause deafness by disrupting mechanoelectrical transduction

    Science.gov (United States)

    Nakanishi, Hiroshi; Kurima, Kiyoto; Kawashima, Yoshiyuki; Griffith, Andrew J.

    2014-01-01

    Objective Mutations of transmembrane channel-like 1 gene (TMC1) can cause dominant (DFNA36) or recessive (DFNB7/B11) deafness. In this article, we describe the characteristics of DFNA36 and DFNB7/B11 deafness, the features of the Tmc1 mutant mouse strains, and recent advances in our understanding of TMC1 function. Methods Publications related to TMC1, DFNA36 or DFNB7/B11 were identified through PubMed. Results All affected DFNA36 subjects showed post-lingual, progressive, sensorineural hearing loss (HL), initially affecting high frequencies. In contrast, almost all affected DFNB7/B11 subjects demonstrated congenital or prelingual severe to profound sensorineural HL. The mouse Tmc1 gene also has dominant and recessive mutant alleles that cause HL in mutant strains, including Beethoven, deafness and Tmc1 knockout mice. These mutant mice have been instrumental for revealing that Tmc1 and its closely related paralog Tmc2 are expressed in cochlear and vestibular hair cells, and are required for hair cell mechanoelectrical transduction (MET). Recent studies suggest that TMC1 and TMC2 may be components of the long-sought hair cell MET channel. Conclusion TMC1 mutations disrupt hair cell MET. PMID:24933710

  19. Unstable mutations: cause of some neurological hereditary diseases

    International Nuclear Information System (INIS)

    Cuenca Berger, P.; Morales Montero, F.

    1999-01-01

    Unstable mutations or amplification of triplets constitute a kind of genetic alteration discovered during the last decade. They had been found inside or near genes important for the normal neurological function of the human being. In some cases, the presence of the amplification causes the inactivation of the gene or the synthesis of a new product which functions different from the original protein. Some common characteristics of diseases caused by the amplification of triplets are that it affects the nervous system and are degenerative in nature. The expression of the manifestations varies according to age. Most of them show genetic anticipation in which the severity of the manifestations increases with each generation and appear at an earlier age. In most cases, the severity of the symptoms is correlated positively to the size of the amplification. The diagnosis of an affected individual in a family may indicate the presence of an altered gene in other relatives. These relatives may not present evident signs of the illness either because it is of late onset or because they carry premutations. The molecular diagnosis of these mutations is important to estimate the risk of developing the disease and/or of transmitting the illness to the descendants and to eliminate the fears of healthy relatives who have inherited normal copies of the gene. (Author) [es

  20. Mutations of TMC1 cause deafness by disrupting mechanoelectrical transduction.

    Science.gov (United States)

    Nakanishi, Hiroshi; Kurima, Kiyoto; Kawashima, Yoshiyuki; Griffith, Andrew J

    2014-10-01

    Mutations of transmembrane channel-like 1 gene (TMC1) can cause dominant (DFNA36) or recessive (DFNB7/B11) deafness. In this article, we describe the characteristics of DFNA36 and DFNB7/B11 deafness, the features of the Tmc1 mutant mouse strains, and recent advances in our understanding of TMC1 function. Publications related to TMC1, DFNA36, or DFNB7/B11 were identified through PubMed. All affected DFNA36 subjects showed post-lingual, progressive, sensorineural hearing loss (HL), initially affecting high frequencies. In contrast, almost all affected DFNB7/B11 subjects demonstrated congenital or prelingual severe to profound sensorineural HL. The mouse Tmc1 gene also has dominant and recessive mutant alleles that cause HL in mutant strains, including Beethoven, deafness, and Tmc1 knockout mice. These mutant mice have been instrumental for revealing that Tmc1 and its closely related paralog Tmc2 are expressed in cochlear and vestibular hair cells, and are required for hair cell mechanoelectrical transduction (MET). Recent studies suggest that TMC1 and TMC2 may be components of the long-sought hair cell MET channel. TMC1 mutations disrupt hair cell MET. Published by Elsevier Ireland Ltd.

  1. Molecular analyses of novel ASAH1 mutations causing Farber lipogranulomatosis: analyses of exonic splicing enhancer inactivating mutation.

    Science.gov (United States)

    Bashyam, M D; Chaudhary, A K; Kiran, M; Reddy, V; Nagarajaram, H A; Dalal, A; Bashyam, L; Suri, D; Gupta, A; Gupta, N; Kabra, M; Puri, R D; RamaDevi, R; Kapoor, S; Danda, S

    2014-12-01

    Farber lipogranulomatosis is a rare autosomal recessive lysosomal storage disorder caused by mutations in the ASAH1 gene. In the largest ever study, we identified and characterized ASAH1 mutations from 11 independent Farber disease (FD) families. A total of 13 different mutations were identified including 1 splice, 1 polypyrimidine tract (PPT) deletion and 11 missense mutations. Eleven mutations were exclusive to the Indian population. The IVS6+4A>G splice and IVS5-16delTTTTC PPT deletion mutations resulted in skipping of exon 6 precluding thereby the region responsible for cleavage of enzyme precursor. A missense mutation (p.V198A) resulted in skipping of exon 8 due to inactivation of an exonic splicing enhancer (ESE) element. This is the first report of mutations affecting PPT and ESE in the ASAH1 gene resulting in FD. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Splicing aberrations caused by constitutional RB1 gene mutations in ...

    Indian Academy of Sciences (India)

    Analysis of RB1 mRNA from blood leukocytes of patients with retinoblastoma identified the effects of mutations involving consensus splice site, exonic substitution and whole-exon deletions identified in genomic DNA of these patients. In addition, this study identified mutations in cases in which no mutations were detectable ...

  3. Lynch Syndrome Caused by Germline PMS2 Mutations

    DEFF Research Database (Denmark)

    Ten Broeke, Sanne W; Brohet, Richard M; Tops, Carli M

    2015-01-01

    years, and there was a significant difference in mean age of CRC between the probands (mean, 47 years; range, 26 to 68 years) and other family members with a PMS2 mutation (mean, 58 years; range, 31 to 86 years; P cancers of the small bowel, ovaries, breast...... families, suggesting the influence of genetic modifiers and lifestyle factors on cancer risks.......PURPOSE: The clinical consequences of PMS2 germline mutations are poorly understood compared with other Lynch-associated mismatch repair gene (MMR) mutations. The aim of this European cohort study was to define the cancer risk faced by PMS2 mutation carriers. METHODS: Data were collected from 98...

  4. [Mutation analysis and prenatal diagnosis in families of X-linked agammaglobulinemia caused by BTK gene mutation].

    Science.gov (United States)

    Kong, Xiangdong; Mo, Guiling; Liu, Ning; Tian, Peichao; Chen, Minfang

    2014-05-13

    To evaluate the genetic diagnostic feasibility of Bruton's tyrosine kinase (BTK) gene in three families with X-linked agammagobulinemia (XLA) birth history, mutation analysis and prenatal genetic diagnosis of BTK gene for two families with XLA. Polymerase chain reaction (PCR) was applied to amplify the regions of exon and exon-intron boundaries of BTK gene in 3 unrelated patients of XLA and their mothers from January 2011 to June 2012. The PCR products were further analyzed by direct sequencing. Prenatal genetic diagnosis was performed by chorionic villus sampling after genotyping of mothers of probands. Three novel mutations of BTK gene were identified in 3 pedigrees of XLA. A missense mutation c.1117C > A (p.L373I) were detected in pedigree 1. The mutation was possible damage by predicting in sillico. A nonsense mutation c.126T > G (p.Y42X) was found in pedigree 2. A single base deletion mutation c.1679delC (p. P560fsX10) was found in pedigree 3. The three mutations, p.L373I, p.Y42X and p. P560fsX10 were novel. The three novel mutations were absent in the 100 normal controls. The male fetus in pedigree 3 was free of mutations identical to the proband and the female fetus in pedigree 2 was a carrier. The two families continued the pregnancies and the infants showed no symptom of XLA after one year old. Three novel mutations were identified. The mutations of p.Y42X and p. P560fsX10 in BTK gene may be the major causes of pedigrees 2 and 3 with XLA. The mutation p.L373I of BTK gene is possibly the cause of pedigree 1 with XLA, but functional verification is needed. For pedigree of XLA, direct sequencing of BTK gene is available for providing genetic counseling, prenatal diagnosis.

  5. Homozygous mutation in the NPHP3 gene causing foetal nephronophthisis

    DEFF Research Database (Denmark)

    Abdullah, Uzma; Farooq, Muhammad; Fatima, Ambrin

    2017-01-01

    We present a case of a foetal sonographic finding of hyper-echogenic kidneys, which led to a strategic series of genetic tests and identified a homozygous mutation (c.424C > T, p. R142*) in the NPHP3 gene. Our study provides a rare presentation of NPHP3-related ciliopathy and adds to the mutation...

  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, IJ; 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. 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

  8. Mutations in KCNT1 cause a spectrum of focal epilepsies

    Science.gov (United States)

    Møller, Rikke S.; Heron, Sarah E.; Larsen, Line H. G.; Lim, Chiao Xin; Ricos, Michael G.; Bayly, Marta A.; van Kempen, Marjan J. A.; Klinkenberg, Sylvia; Andrews, Ian; Kelley, Kent; Ronen, Gabriel M.; Callen, David; McMahon, Jacinta M.; Yendle, Simone C.; Carvill, Gemma L.; Mefford, Heather C.; Nabbout, Rima; Poduri, Annapurna; Striano, Pasquale; Baglietto, Maria G.; Zara, Federico; Smith, Nicholas J.; Pridmore, Clair; Gardella, Elena; Nikanorova, Marina; Dahl, Hans Atli; Gellert, Pia; Scheffer, Ingrid E.; Gunning, Boudewijn; Kragh-Olsen, Bente; Dibbens, Leanne M.

    2018-01-01

    Summary Autosomal dominant mutations in the sodium-gated potassium channel subunit gene KCNT1 have been associated with two distinct seizure syndromes, nocturnal frontal lobe epilepsy (NFLE) and malignant migrating focal seizures of infancy (MMFSI). To further explore the phenotypic spectrum associated with KCNT1, we examined individuals affected with focal epilepsy or an epileptic encephalopathy for mutations in the gene. We identified KCNT1 mutations in 12 previously unreported patients with focal epilepsy, multifocal epilepsy, cardiac arrhythmia, and in a family with sudden unexpected death in epilepsy (SUDEP), in addition to patients with NFLE and MMFSI. In contrast to the 100% penetrance so far reported for KCNT1 mutations, we observed incomplete penetrance. It is notable that we report that the one KCNT1 mutation, p.Arg398Gln, can lead to either of the two distinct phenotypes, ADNFLE or MMFSI, even within the same family. This indicates that genotype–phenotype relationships for KCNT1 mutations are not straightforward. We demonstrate that KCNT1 mutations are highly pleiotropic and are associated with phenotypes other than ADNFLE and MMFSI. KCNT1 mutations are now associated with Ohtahara syndrome, MMFSI, and nocturnal focal epilepsy. They may also be associated with multifocal epilepsy and cardiac disturbances. PMID:26122718

  9. Oxidative Stress in Dilated Cardiomyopathy Caused by MYBPC3 Mutation

    NARCIS (Netherlands)

    T.L. Lynch (Thomas L.); M. Sivaguru (Mayandi); M. Velayutham (Murugesan); A.J. Cardounel (Arturo J.); M. Michels (Michelle); D. Barefield (David); S. Govindan (Suresh); C.D. Remedios (Cristobal Dos); J. van der Velden (Jolanda); S. Sadayappan (Sakthivel)

    2015-01-01

    textabstractCardiomyopathies can result from mutations in genes encoding sarcomere proteins including MYBPC3, which encodes cardiac myosin binding protein-C (cMyBP-C). However, whether oxidative stress is augmented due to contractile dysfunction and cardiomyocyte damage in MYBPC3-mutated

  10. FKRP mutations, including a founder mutation, cause phenotype variability in Chinese patients with dystroglycanopathies.

    Science.gov (United States)

    Fu, Xiaona; Yang, Haipo; Wei, Cuijie; Jiao, Hui; Wang, Shuo; Yang, Yanling; Han, Chunxi; Wu, Xiru; Xiong, Hui

    2016-12-01

    Mutations in the fukutin-related protein (FKRP) gene have been associated with dystroglycanopathies, which are common in Europe but rare in Asia. Our study aimed to retrospectively analyze and characterize the clinical, myopathological and genetic features of 12 Chinese patients with FKRP mutations. Three patients were diagnosed with congenital muscular dystrophy type 1C (MDC1C) and nine patients were diagnosed with limb girdle muscular dystrophy type 2I (LGMD2I). Three muscle biopsy specimens had dystrophic changes and reduced glycosylated α-dystroglycan staining, and two showed reduced expression of laminin α2. Two known and 13 novel mutations were identified in our single center cohort. Interestingly, the c.545A>G mutation was found in eight of the nine LGMD2I patients as a founder mutation and this founder mutation in Chinese patients differs from the one seen in European patients. Moreover, patients homozygous for the c.545A>G mutation were clinically asymptomatic, a less severe phenotype than in compound heterozygous patients with the c.545A>G mutation. The 13 novel mutations of FKRP significantly expanded the mutation spectrum of MDC1C and LGMD2I, and the different founder mutations indicate the ethnic difference in FKRP mutations.

  11. Characteristics, causes and evolutionary consequences of male-biased mutation.

    Science.gov (United States)

    Ellegren, Hans

    2007-01-07

    Mutation has traditionally been considered a random process, but this paradigm is challenged by recent evidence of divergence rate heterogeneity in different genomic regions. One facet of mutation rate variation is the propensity for genetic change to correlate with the number of germ cell divisions, reflecting the replication-dependent origin of many mutations. Haldane was the first to connect this association of replication and mutation to the difference in the number of cell divisions in oogenesis (low) and spermatogenesis (usually high), and the resulting sex difference in the rate of mutation. The concept of male-biased mutation has been thoroughly analysed in recent years using an evolutionary approach, in which sequence divergence of autosomes and/or sex chromosomes are compared to allow inference about the relative contribution of mothers and fathers in the accumulation of mutations. For instance, assuming that a neutral sequence is analysed, that rate heterogeneity owing to other factors is cancelled out by the investigation of many loci and that the effect of ancestral polymorphism is properly taken into account, the male-to-female mutation rate ratio, alpham, can be solved from the observed difference in rate of X and Y chromosome divergence. The male mutation bias is positively correlated with the relative excess of cell divisions in the male compared to the female germ line, as evidenced by a generation time effect: in mammals, alpham is estimated at approximately 4-6 in primates, approximately 3 in carnivores and approximately 2 in small rodents. Another life-history correlate is sexual selection: when there is intense sperm competition among males, increased sperm production will be associated with a larger number of mitotic cell divisions in spermatogenesis and hence an increase in alpham. Male-biased mutation has implications for important aspects of evolutionary biology such as mate choice in relation to mutation load, sexual selection and the

  12. Congenital myopathy is caused by mutation of HACD1

    OpenAIRE

    Muhammad, Emad; Reish, Orit; Ohno, Yusuke; Scheetz, Todd; DeLuca, Adam; Searby, Charles; Regev, Miriam; Benyamini, Lilach; Fellig, Yakov; Kihara, Akio; Sheffield, Val C.; Parvari, Ruti

    2013-01-01

    Congenital myopathies are heterogeneous inherited diseases of muscle characterized by a range of distinctive histologic abnormalities. We have studied a consanguineous family with congenital myopathy. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous non-sense mutation in 3-hydroxyacyl-CoA dehydratase 1 (HACD1) in affected individuals. The mutation results in non-sense mediated decay of the HACD1 mRNA to 31% of control levels in patient muscle and completely abro...

  13. Error-prone polymerase activity causes multinucleotide mutations in humans.

    Science.gov (United States)

    Harris, Kelley; Nielsen, Rasmus

    2014-09-01

    About 2% of human genetic polymorphisms have been hypothesized to arise via multinucleotide mutations (MNMs), complex events that generate SNPs at multiple sites in a single generation. MNMs have the potential to accelerate the pace at which single genes evolve and to confound studies of demography and selection that assume all SNPs arise independently. In this paper, we examine clustered mutations that are segregating in a set of 1092 human genomes, demonstrating that the signature of MNM becomes enriched as large numbers of individuals are sampled. We estimate the percentage of linked SNP pairs that were generated by simultaneous mutation as a function of the distance between affected sites and show that MNMs exhibit a high percentage of transversions relative to transitions, findings that are reproducible in data from multiple sequencing platforms and cannot be attributed to sequencing error. Among tandem mutations that occur simultaneously at adjacent sites, we find an especially skewed distribution of ancestral and derived alleles, with GC → AA, GA → TT, and their reverse complements making up 27% of the total. These mutations have been previously shown to dominate the spectrum of the error-prone polymerase Pol ζ, suggesting that low-fidelity DNA replication by Pol ζ is at least partly responsible for the MNMs that are segregating in the human population. We develop statistical estimates of MNM prevalence that can be used to correct phylogenetic and population genetic inferences for the presence of complex mutations. © 2014 Harris and Nielsen; Published by Cold Spring Harbor Laboratory Press.

  14. Disabilities caused by unstable mutations in Costa Rica

    Directory of Open Access Journals (Sweden)

    Patricia Cuenca

    2004-09-01

    Full Text Available La distrofia miotónica tipo1 (DM1 y el síndrome del cromosoma X frágil (FRAXA son dos enfermedades hereditarias relativamente comunes. Ambas constituyen ejemplos de un nuevo tipo de mecanismo mutacional, llamado mutaciones inestables o dinámicas, expansión de tripletas, o amplificación del ADN. La DM1 se considera como la distrofia muscular más frecuente en los adultos y FRAXA es la principal causa de retardo mental hereditario. Este trabajo presenta resultados actualizados de un estudio prospectivo no aleatorio en pacientes clínicamente afectados, que se realiza con el objetivo de confirmar el diagnóstico con técnicas moleculares (Hibridación de Southern y reacción en cadena de la polimerasa, PCR, y llevar a cabo el tamizaje en cascada del resto de la familia para ofrecerles consejo genético adecuado. Se confirmó el diagnóstico clínico inicial en la mayoría de los casos de distrofia miotónica, pero en los casos con retardo mental, más de la mitad de los análisis resultaron negativos para la amplificación en el gen FMR1, específica de FRAXA. La razón principal para esto podría ser el cuadro clínico muy sutil que muestran los niños afectados antes de la pubertad. Los únicos métodos disponibles para prevenir estas discapacidades por el momento son, el tamizaje en cascada, el consejo genético y el aborto selectivo. De los cuales, el último no se puede llevar a cabo según las leyes vigentes en Costa Rica.Myotonic dystrophy and fragile X syndrome are two genetically determined relatively common disabilities. Both are examples of a new type of mutation mechanism called unstable or dynamic mutations, triple repeats expansions or DNA amplification. Fragile X syndrome is recognized as the main cause of hereditary mental retardation and myotonic dystrophy is considered the most common muscular dystrophy of adults. This is a prospective non randomized study of clinically affected people, in order to confirm the diagnosis with

  15. Mutations in PAX3 that cause Waardenburg syndrome type I: Ten new mutations and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, C.T.; Hoth, C.F.; Milunsky, A. [Boston Univ. School of Medicine, MA (United States)] [and others

    1995-08-28

    Waardenburg syndrome (WS) is an autosomal-dominant disorder characterized by sensorineural hearing loss, dystopia canthorum, and pigmentary disturbances, and it represents the most common form of inherited deafness in infants. WS type I is characterized by the presence of dystopia canthorum, while individuals with WS type II have normally-located canthi. WS type III is similar to WS type I but is also characterized by musculoskeletal abnormalities. Defects in the PAX3 gene, a transcription factor expressed during embryonic development, have been shown to cause WS types I and III in several families. In contrast, mutations in PAX3 do not cause WS type II, and linkage of the disease to other chromosomal regions has been demonstrated. We describe 10 additional mutations in the PAX3 gene in families with WS type I. Eight of these mutations are in the region of PAX3, where only one mutation has been previously described. These mutations, together with those previously reported, cover essentially the entire PAX3 gene and represent a wide spectrum of mutations that can cause WS type I. Thus far, all but one of the mutations are private; only one mutation has been reported in two apparently unrelated families. Our analysis thus far demonstrates little correlation between genotype and phenotype; deletions of the entire PAX3 gene result in phenotypes indistinguishable from those associated with single-base substitutions in the paired domain or homeodomain of PAX3. Moreover, two similar mutations in close proximity can result in significantly different phenotypes, WS type I in one family and WS type III in another. 47 refs., 3 figs., 5 tabs.

  16. Oxidative Stress in Dilated Cardiomyopathy Caused by MYBPC3 Mutation

    Directory of Open Access Journals (Sweden)

    Thomas L. Lynch

    2015-01-01

    Full Text Available Cardiomyopathies can result from mutations in genes encoding sarcomere proteins including MYBPC3, which encodes cardiac myosin binding protein-C (cMyBP-C. However, whether oxidative stress is augmented due to contractile dysfunction and cardiomyocyte damage in MYBPC3-mutated cardiomyopathies has not been elucidated. To determine whether oxidative stress markers were elevated in MYBPC3-mutated cardiomyopathies, a previously characterized 3-month-old mouse model of dilated cardiomyopathy (DCM expressing a homozygous MYBPC3 mutation (cMyBP-C(t/t was used, compared to wild-type (WT mice. Echocardiography confirmed decreased percentage of fractional shortening in DCM versus WT hearts. Histopathological analysis indicated a significant increase in myocardial disarray and fibrosis while the second harmonic generation imaging revealed disorganized sarcomeric structure and myocyte damage in DCM hearts when compared to WT hearts. Intriguingly, DCM mouse heart homogenates had decreased glutathione (GSH/GSSG ratio and increased protein carbonyl and lipid malondialdehyde content compared to WT heart homogenates, consistent with elevated oxidative stress. Importantly, a similar result was observed in human cardiomyopathy heart homogenate samples. These results were further supported by reduced signals for mitochondrial semiquinone radicals and Fe-S clusters in DCM mouse hearts measured using electron paramagnetic resonance spectroscopy. In conclusion, we demonstrate elevated oxidative stress in MYPBC3-mutated DCM mice, which may exacerbate the development of heart failure.

  17. Mutations that Cause Human Disease: A Computational/Experimental Approach

    Energy Technology Data Exchange (ETDEWEB)

    Beernink, P; Barsky, D; Pesavento, B

    2006-01-11

    International genome sequencing projects have produced billions of nucleotides (letters) of DNA sequence data, including the complete genome sequences of 74 organisms. These genome sequences have created many new scientific opportunities, including the ability to identify sequence variations among individuals within a species. These genetic differences, which are known as single nucleotide polymorphisms (SNPs), are particularly important in understanding the genetic basis for disease susceptibility. Since the report of the complete human genome sequence, over two million human SNPs have been identified, including a large-scale comparison of an entire chromosome from twenty individuals. Of the protein coding SNPs (cSNPs), approximately half leads to a single amino acid change in the encoded protein (non-synonymous coding SNPs). Most of these changes are functionally silent, while the remainder negatively impact the protein and sometimes cause human disease. To date, over 550 SNPs have been found to cause single locus (monogenic) diseases and many others have been associated with polygenic diseases. SNPs have been linked to specific human diseases, including late-onset Parkinson disease, autism, rheumatoid arthritis and cancer. The ability to predict accurately the effects of these SNPs on protein function would represent a major advance toward understanding these diseases. To date several attempts have been made toward predicting the effects of such mutations. The most successful of these is a computational approach called ''Sorting Intolerant From Tolerant'' (SIFT). This method uses sequence conservation among many similar proteins to predict which residues in a protein are functionally important. However, this method suffers from several limitations. First, a query sequence must have a sufficient number of relatives to infer sequence conservation. Second, this method does not make use of or provide any information on protein structure, which

  18. Mutations in the NHEJ component XRCC4 cause primordial dwarfism

    NARCIS (Netherlands)

    J.E. Murray (Jennie E.); M. van der Burg (Mirjam); H. IJspeert (Hanna); P. Carroll (Paula); Q. Wu (Qian); T. Ochi (Takashi); A. Leitch (Andrea); E.S. Miller (Edward S.); B. Kysela (Boris); A. Jawad (Alireza); A. Bottani (Armand); F. Brancati (Fred); M. Cappa (Marco); V. Cormier-Daire (Valerie); C. Deshpande (Charu); E.A. Faqeih (Eissa A.); G.E. Graham (Gail E.); E. Ranza (Emmanuelle); T.L. Blundell (Tom L.); A.P. Jackson (Andrew); G.S. Stewart (Grant S.); L.S. Bicknell (Louise)

    2015-01-01

    textabstractNon-homologous end joining (NHEJ) is a key cellular process ensuring genome integrity. Mutations in several components of the NHEJ pathway have been identified, often associated with severe combined immunodeficiency (SCID), consistent with the requirement for NHEJ during V(D)J

  19. Cantu syndrome is caused by mutations in ABCC9

    NARCIS (Netherlands)

    van Bon, B.W.; Gilissen, C.F.H.A.; Grange, D.K.; Hennekam, R.C.; Kayserili, H.; Engels, H.; Reutter, H.; Ostergaard, J.R.; Morava, E.; Tsiakas, K.; Isidor, B.; Le Merrer, M.; Eser, M.; Wieskamp, N.; de Vries, P.; Steehouwer, M.; Veltman, J.A.; Robertson, S.P.; Brunner, H.G.; Vries, L.B.A. de; Hoischen, A.

    2012-01-01

    Cantu syndrome is a rare disorder characterized by congenital hypertrichosis, neonatal macrosomia, a distinct osteochondrodysplasia, and cardiomegaly. Using an exome-sequencing approach applied to one proband-parent trio and three unrelated single cases, we identified heterozygous mutations in ABCC9

  20. Cantu Syndrome Is Caused by Mutations in ABCC9

    NARCIS (Netherlands)

    van Bon, Bregje W. M.; Gilissen, Christian; Grange, Dorothy K.; Hennekam, Raoul C. M.; Kayserili, Hülya; Engels, Hartmut; Reutter, Heiko; Ostergaard, John R.; Morava, Eva; Tsiakas, Konstantinos; Isidor, Bertrand; Le Merrer, Martine; Eser, Metin; Wieskamp, Nienke; de Vries, Petra; Steehouwer, Marloes; Veltman, Joris A.; Robertson, Stephen P.; Brunner, Han G.; de Vries, Bert B. A.; Hoischen, Alexander

    2012-01-01

    Cantu syndrome is a rare disorder characterized by congenital hypertrichosis, neonatal macrosomia, a distinct osteochondrodysplasia, and cardiomegaly. Using an exome-sequencing approach applied to one proband-parent trio and three unrelated single cases, we identified heterozygous mutations in ABCC9

  1. Mutations in KCNT1 cause a spectrum of focal epilepsies

    DEFF Research Database (Denmark)

    Møller, Rikke Steensbjerre; Heron, Sarah E.; Larsen, Line H. G.

    2015-01-01

    Autosomal dominant mutations in the sodium-gated potassium channel subunit gene KCNT1 have been associated with two distinct seizure syndromes, nocturnal frontal lobe epilepsy (NFLE) and malignant migrating focal seizures of infancy (MMFSI). To further explore the phenotypic spectrum associated w...

  2. FGFR3 mutation causes abnormal membranous ossification in achondroplasia.

    Science.gov (United States)

    Di Rocco, Federico; Biosse Duplan, Martin; Heuzé, Yann; Kaci, Nabil; Komla-Ebri, Davide; Munnich, Arnold; Mugniery, Emilie; Benoist-Lasselin, Catherine; Legeai-Mallet, Laurence

    2014-06-01

    FGFR3 gain-of-function mutations lead to both chondrodysplasias and craniosynostoses. Achondroplasia (ACH), the most frequent dwarfism, is due to an FGFR3-activating mutation which results in impaired endochondral ossification. The effects of the mutation on membranous ossification are unknown. Fgfr3(Y367C/+) mice mimicking ACH and craniofacial analysis of patients with ACH and FGFR3-related craniosynostoses provide an opportunity to address this issue. Studying the calvaria and skull base, we observed abnormal cartilage and premature fusion of the synchondroses leading to modifications of foramen magnum shape and size in Fgfr3(Y367C/+) mice, ACH and FGFR3-related craniosynostoses patients. Partial premature fusion of the coronal sutures and non-ossified gaps in frontal bones were also present in Fgfr3(Y367C/+) mice and ACH patients. Our data provide strong support that not only endochondral ossification but also membranous ossification is severely affected in ACH. Demonstration of the impact of FGFR3 mutations on craniofacial development should initiate novel pharmacological and surgical therapeutic approaches.

  3. TUBB4A de novo mutations cause isolated hypomyelination

    NARCIS (Netherlands)

    Pizzino, Amy; Pierson, Tyler Mark; Guo, Yiran; Helman, Guy; Fortini, Sebastian; Guerrero, Kether; Saitta, Sulagna; Murphy, Jennifer Louise Patrick; Padiath, Quasar; Xie, Yi; Hakonarson, Hakon; Xu, Xun; Funari, Tara; Fox, Michelle; Taft, Ryan J.; van der Knaap, Marjo S.; Bernard, Geneviève; Schiffmann, Raphael; Simons, Cas; Vanderver, Adeline

    2014-01-01

    We present a series of unrelated patients with isolated hypomyelination, with or without mild cerebellar atrophy, and de novo TUBB4A mutations. Patients in 2 large institutional review board-approved leukodystrophy bioregistries at Children's National Medical Center and Montreal Children's Hospital

  4. Two novel mutations in ILDR1 gene cause autosomal recessive ...

    Indian Academy of Sciences (India)

    Social Welfare and Rehabilitation Sciences, for genetic diag- nosis. According to the guidelines of the Ethic Committee .... (b) Pure tone air and bone conduction audiograms from left (blue) and right (red) ears of an affected individual in each family. (c) Sequence chromatographs of the mutated part of the ILDR1 gene in ...

  5. Splicing aberrations caused by constitutional RB1 gene mutations in ...

    Indian Academy of Sciences (India)

    Analysis of RB1 mRNA from blood leukocytes of patients with retinoblastoma identified the effects of mutations involving consensus splice site, .... bilateral Rb. Genomic DNA analysis from peripheral blood was as described by Parsam .... the patterns are not always the same in different studies (Klutz et al. 2002; Taylor et al.

  6. Two Novel De Novo GARS Mutations Cause Early-Onset Axonal Charcot-Marie-Tooth Disease.

    Directory of Open Access Journals (Sweden)

    Yi-Chu Liao

    Full Text Available Mutations in the GARS gene have been identified in a small number of patients with Charcot-Marie-Tooth disease (CMT type 2D or distal spinal muscular atrophy type V, for whom disease onset typically occurs during adolescence or young adulthood, initially manifesting as weakness and atrophy of the hand muscles. The role of GARS mutations in patients with inherited neuropathies in Taiwan remains elusive.Mutational analyses of the coding regions of GARS were performed using targeted sequencing of 54 patients with molecularly unassigned axonal CMT, who were selected from 340 unrelated CMT patients. Two heterozygous mutations in GARS, p.Asp146Tyr and p.Met238Arg, were identified; one in each patient. Both are novel de novo mutations. The p.Asp146Tyr mutation is associated with a severe infantile-onset neuropathy and the p.Met238Arg mutation results in childhood-onset disability.GARS mutations are an uncommon cause of CMT in Taiwan. The p.Asp146Tyr and p.Met238Arg mutations are associated with early-onset axonal CMT. These findings broaden the mutational spectrum of GARS and also highlight the importance of considering GARS mutations as a disease cause in patients with early-onset neuropathies.

  7. GRIN1 mutations cause encephalopathy with infantile-onset epilepsy, and hyperkinetic and stereotyped movement disorders.

    Science.gov (United States)

    Ohba, Chihiro; Shiina, Masaaki; Tohyama, Jun; Haginoya, Kazuhiro; Lerman-Sagie, Tally; Okamoto, Nobuhiko; Blumkin, Lubov; Lev, Dorit; Mukaida, Souichi; Nozaki, Fumihito; Uematsu, Mitsugu; Onuma, Akira; Kodera, Hirofumi; Nakashima, Mitsuko; Tsurusaki, Yoshinori; Miyake, Noriko; Tanaka, Fumiaki; Kato, Mitsuhiro; Ogata, Kazuhiro; Saitsu, Hirotomo; Matsumoto, Naomichi

    2015-06-01

    Recently, de novo mutations in GRIN1 have been identified in patients with nonsyndromic intellectual disability and epileptic encephalopathy. Whole exome sequencing (WES) analysis of patients with genetically unsolved epileptic encephalopathies identified four patients with GRIN1 mutations, allowing us to investigate the phenotypic spectrum of GRIN1 mutations. Eighty-eight patients with unclassified early onset epileptic encephalopathies (EOEEs) with an age of onset A) with a mutant allele frequency of 16% (in DNA of blood leukocytes) was detected in one patient. Three mutations were located in the transmembrane domain (3/4, 75%), and one in the extracellular loop near transmembrane helix 1. All the mutations were predicted to impair the function of the NMDA receptor. Clinical features of de novo GRIN1 mutations include infantile involuntary movements, seizures, and hand stereotypies, suggesting that GRIN1 mutations cause encephalopathy resulting in seizures and movement disorders. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

  8. Nocturnal frontal lobe epilepsy caused by a mutation in the GATOR1 complex gene NPRL3.

    Science.gov (United States)

    Korenke, Georg-Christoph; Eggert, Marlene; Thiele, Holger; Nürnberg, Peter; Sander, Thomas; Steinlein, Ortrud K

    2016-03-01

    Mutations in NPRL3, one of three genes that encode proteins of the mTORC1-regulating GATOR1 complex, have recently been reported to cause cortical dysplasia with focal epilepsy. We have now analyzed a multiplex epilepsy family by whole exome sequencing and identified a frameshift mutation (NM_001077350.2; c.1522delG; p.E508Rfs*46) within exon 13 of NPRL3. This truncating mutation causes an epilepsy phenotype characterized by early childhood onset of mainly nocturnal frontal lobe epilepsy. The penetrance in our family was low (three affected out of six mutation carriers), compared to families with either ion channel- or DEPDC5-associated familial nocturnal frontal lobe epilepsy. The absence of apparent structural brain abnormalities suggests that mutations in NPRL3 are not necessarily associated with focal cortical dysplasia but might be able to cause epilepsy by different, yet unknown pathomechanisms. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

  9. Mutations in the CEP290 (NPHP6) Gene Are a Frequent Cause of Leber Congenital Amaurosis

    Science.gov (United States)

    den Hollander, Anneke I.; Koenekoop, Robert K.; Yzer, Suzanne; Lopez, Irma; Arends, Maarten L.; Voesenek, Krysta E. J.; Zonneveld, Marijke N.; Strom, Tim M.; Meitinger, Thomas; Brunner, Han G.; Hoyng, Carel B.; van den Born, L. Ingeborgh; Rohrschneider, Klaus; Cremers, Frans P. M.

    2006-01-01

    Leber congenital amaurosis (LCA) is one of the main causes of childhood blindness. To date, mutations in eight genes have been described, which together account for ∼45% of LCA cases. We localized the genetic defect in a consanguineous LCA-affected family from Quebec and identified a splice defect in a gene encoding a centrosomal protein (CEP290). The defect is caused by an intronic mutation (c.2991+1655A→G) that creates a strong splice-donor site and inserts a cryptic exon in the CEP290 messenger RNA. This mutation was detected in 16 (21%) of 76 unrelated patients with LCA, either homozygously or in combination with a second deleterious mutation on the other allele. CEP290 mutations therefore represent one of the most frequent causes of LCA identified so far. PMID:16909394

  10. TSEN54 mutations cause pontocerebellar hypoplasia type 5

    OpenAIRE

    Namavar, Yasmin; Chitayat, David; Barth, Peter G; van Ruissen, Fred; de Wissel, Marit B; Poll-The, Bwee Tien; Silver, Rachel; Baas, Frank

    2011-01-01

    Pontocerebellar hypoplasia (PCH) is a group of autosomal recessive neurodegenerative disorders characterized by prenatal onset of stunted brain growth and progressive atrophy predominantly affecting cerebellum, pons and olivary nuclei, and to a lesser extent also the cerebral cortex. Six subtypes (PCH1–6) were described and genes for four types (PCH1, 2, 4 and 6) were identified. Mutations in the tRNA splicing endonuclease subunit (TSEN) genes 54, 2 and 34 are found in PCH2 and PCH4. One fami...

  11. Mutations in DNMT1 cause autosomal dominant cerebellar ataxia, deafness and narcolepsy

    DEFF Research Database (Denmark)

    Winkelmann, Juliane; Lin, Ling; Schormair, Barbara

    2012-01-01

    to HDAC2. It is also highly expressed in immune cells and required for the differentiation of CD4+ into T regulatory cells. Mutations in exon 20 of this gene were recently reported to cause hereditary sensory neuropathy with dementia and hearing loss (HSAN1). Our mutations are all located in exon 21...

  12. Dominant beta-catenin mutations cause intellectual disability with recognizable syndromic features

    NARCIS (Netherlands)

    Tucci, V.; Kleefstra, T.; Hardy, A.; Heise, I.; Maggi, S.; Willemsen, M.H.; Hilton, H.; Esapa, C.; Simon, M.; Buenavista, M.T.; McGuffin, L.J.; Vizor, L.; Dodero, L.; Tsaftaris, S.; Romero, R.; Nillesen, W.N.; Vissers, L.E.L.M.; Kempers, M.J.E.; Silfhout, A.T. van; Iqbal, Z.; Orlando, M.; Maccione, A.; Lassi, G.; Farisello, P.; Contestabile, A.; Tinarelli, F.; Nieus, T.; Raimondi, A.; Greco, B.; Cantatore, D.; Gasparini, L.; Berdondini, L.; Bifone, A.; Gozzi, A.; Wells, S.; Nolan, P.M.

    2014-01-01

    The recent identification of multiple dominant mutations in the gene encoding beta-catenin in both humans and mice has enabled exploration of the molecular and cellular basis of beta-catenin function in cognitive impairment. In humans, beta-catenin mutations that cause a spectrum of

  13. Novel COL4A1 mutations cause cerebral small vessel disease by haploinsufficiency

    NARCIS (Netherlands)

    Lemmens, R.; Maugeri, A.; Niessen, H.W.M.; Goris, A.; Tousseyn, T.; Demaerel, P.; Corveleyn, A.; Robberecht, W.; van der Knaap, M.S.; Thijs, V.N.; Zwijnenburg, P.J.G.

    2013-01-01

    Mutations in COL4A1 have been identified in families with hereditary small vessel disease of the brain presumably due to a dominant-negative mechanism. Here, we report on two novel mutations in COL4A1 in two families with porencephaly, intracerebral hemorrhage and severe white matter disease caused

  14. Clinical course of cone dystrophy caused by mutations in the RPGR gene

    NARCIS (Netherlands)

    Thiadens, Alberta A. H. J.; Soerjoesing, Gyan G.; Florijn, Ralph J.; Tjiam, A. G.; den Hollander, Anneke I.; van den Born, L. Ingeborgh; Riemslag, Frans C.; Bergen, Arthur A. B.; Klaver, Caroline C. W.

    2011-01-01

    Mutations in the RPGR gene predominantly cause rod photoreceptor disorders with a large variability in clinical course. In this report, we describe two families with mutations in this gene and cone involvement. We investigated an X-linked cone dystrophy family (1) with 25 affected males, 25 female

  15. Clinical course of cone dystrophy caused by mutations in the RPGR gene

    NARCIS (Netherlands)

    Thiadens, A.A.H.J.; Soerjoesing, G.G.; Florijn, R.J.; Tjiam, A.G.; Hollander, A.I. den; Born, L.I. van den; Riemslag, F.C.; Bergen, A.A.B.; Klaver, C.C.

    2011-01-01

    BACKGROUND: Mutations in the RPGR gene predominantly cause rod photoreceptor disorders with a large variability in clinical course. In this report, we describe two families with mutations in this gene and cone involvement. METHODS: We investigated an X-linked cone dystrophy family (1) with 25

  16. Clinical course of cone dystrophy caused by mutations in the RPGR gene

    NARCIS (Netherlands)

    A.A.H.J. Thiadens (Alberta); G.G. Soerjoesing (Gyan); R.J. Florijn; A.G. Tjiam; A.I. Hollander (Anneke); L.I. van den Born (Ingeborgh); F.C.C. Riemslag (Frans); A.A.B. Bergen (Arthur); C.C.W. Klaver (Caroline)

    2011-01-01

    textabstractBackground: Mutations in the RPGR gene predominantly cause rod photoreceptor disorders with a large variability in clinical course. In this report, we describe two families with mutations in this gene and cone involvement. Methods: We investigated an X-linked cone dystrophy family (1)

  17. Late onset axonal Charcot-Marie-Tooth phenotype caused by a novel myelin protein zero mutation

    NARCIS (Netherlands)

    Bienfait, H. M. E.; Faber, C. G.; Baas, F.; Gabreëls-Festen, A. A. W. M.; Koelman, J. H. T. M.; Hoogendijk, J. E.; Verschuuren, J. J.; Wokke, J. H. J.; de Visser, M.

    2006-01-01

    A late onset axonal Charcot-Marie-Tooth phenotype is described, resulting from a novel mutation in the myelin protein zero (MPZ) gene. Comparative computer modelling of the three dimensional structure of the MPZ protein predicts that this mutation does not cause a significant structural change. The

  18. LPIN1 gene mutations: a major cause of severe rhabdomyolysis in early childhood

    NARCIS (Netherlands)

    Michot, Caroline; Hubert, Laurence; Brivet, Michèle; de Meirleir, Linda; Valayannopoulos, Vassili; Müller-Felber, Wolfgang; Venkateswaran, Ramesh; Ogier, Hélène; Desguerre, Isabelle; Altuzarra, Cécilia; Thompson, Elizabeth; Smitka, Martin; Huebner, Angela; Husson, Marie; Horvath, Rita; Chinnery, Patrick; Vaz, Frederic M.; Munnich, Arnold; Elpeleg, Orly; Delahodde, Agnès; de Keyzer, Yves; de Lonlay, Pascale

    2010-01-01

    Autosomal recessive LPIN1 mutations have been recently described as a novel cause of rhabdomyolysis in a few families. The purpose of the study was to evaluate the prevalence of LPIN1 mutations in patients exhibiting severe episodes of rhabdomyolysis in infancy. After exclusion of primary fatty acid

  19. Phenotype and genotype in 52 patients with Rubinstein-Taybi syndrome caused by EP300 mutations.

    Science.gov (United States)

    Fergelot, Patricia; Van Belzen, Martine; Van Gils, Julien; Afenjar, Alexandra; Armour, Christine M; Arveiler, Benoit; Beets, Lex; Burglen, Lydie; Busa, Tiffany; Collet, Marie; Deforges, Julie; de Vries, Bert B A; Dominguez Garrido, Elena; Dorison, Nathalie; Dupont, Juliette; Francannet, Christine; Garciá-Minaúr, Sixto; Gabau Vila, Elisabeth; Gebre-Medhin, Samuel; Gener Querol, Blanca; Geneviève, David; Gérard, Marion; Gervasini, Cristina Giovanna; Goldenberg, Alice; Josifova, Dragana; Lachlan, Katherine; Maas, Saskia; Maranda, Bruno; Moilanen, Jukka S; Nordgren, Ann; Parent, Philippe; Rankin, Julia; Reardon, Willie; Rio, Marlène; Roume, Joëlle; Shaw, Adam; Smigiel, Robert; Sojo, Amaia; Solomon, Benjamin; Stembalska, Agnieszka; Stumpel, Constance; Suarez, Francisco; Terhal, Paulien; Thomas, Simon; Touraine, Renaud; Verloes, Alain; Vincent-Delorme, Catherine; Wincent, Josephine; Peters, Dorien J M; Bartsch, Oliver; Larizza, Lidia; Lacombe, Didier; Hennekam, Raoul C

    2016-12-01

    Rubinstein-Taybi syndrome (RSTS) is a developmental disorder characterized by a typical face and distal limbs abnormalities, intellectual disability, and a vast number of other features. Two genes are known to cause RSTS, CREBBP in 60% and EP300 in 8-10% of clinically diagnosed cases. Both paralogs act in chromatin remodeling and encode for transcriptional co-activators interacting with >400 proteins. Up to now 26 individuals with an EP300 mutation have been published. Here, we describe the phenotype and genotype of 42 unpublished RSTS patients carrying EP300 mutations and intragenic deletions and offer an update on another 10 patients. We compare the data to 308 individuals with CREBBP mutations. We demonstrate that EP300 mutations cause a phenotype that typically resembles the classical RSTS phenotype due to CREBBP mutations to a great extent, although most facial signs are less marked with the exception of a low-hanging columella. The limb anomalies are more similar to those in CREBBP mutated individuals except for angulation of thumbs and halluces which is very uncommon in EP300 mutated individuals. The intellectual disability is variable but typically less marked whereas the microcephaly is more common. All types of mutations occur but truncating mutations and small rearrangements are most common (86%). Missense mutations in the HAT domain are associated with a classical RSTS phenotype but otherwise no genotype-phenotype correlation is detected. Pre-eclampsia occurs in 12/52 mothers of EP300 mutated individuals versus in 2/59 mothers of CREBBP mutated individuals, making pregnancy with an EP300 mutated fetus the strongest known predictor for pre-eclampsia. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Recessive Osteogenesis Imperfecta Caused by Missense Mutations in SPARC

    Science.gov (United States)

    Mendoza-Londono, Roberto; Fahiminiya, Somayyeh; Majewski, Jacek; Tétreault, Martine; Nadaf, Javad; Kannu, Peter; Sochett, Etienne; Howard, Andrew; Stimec, Jennifer; Dupuis, Lucie; Roschger, Paul; Klaushofer, Klaus; Palomo, Telma; Ouellet, Jean; Al-Jallad, Hadil; Mort, John S.; Moffatt, Pierre; Boudko, Sergei; Bächinger, Hans-Peter; Rauch, Frank

    2015-01-01

    Secreted protein, acidic, cysteine-rich (SPARC) is a glycoprotein that binds to collagen type I and other proteins in the extracellular matrix. Using whole-exome sequencing to identify the molecular defect in two unrelated girls with severe bone fragility and a clinical diagnosis of osteogenesis imperfecta type IV, we identified two homozygous variants in SPARC (GenBank: NM_003118.3; c.497G>A [p.Arg166His] in individual 1; c.787G>A [p.Glu263Lys] in individual 2). Published modeling and site-directed mutagenesis studies had previously shown that the residues substituted by these mutations form an intramolecular salt bridge in SPARC and are essential for the binding of SPARC to collagen type I. The amount of SPARC secreted by skin fibroblasts was reduced in individual 1 but appeared normal in individual 2. The migration of collagen type I alpha chains produced by these fibroblasts was mildly delayed on SDS-PAGE gel, suggesting some overmodification of collagen during triple helical formation. Pulse-chase experiments showed that collagen type I secretion was mildly delayed in skin fibroblasts from both individuals. Analysis of an iliac bone sample from individual 2 showed that trabecular bone was hypermineralized on the material level. In conclusion, these observations show that homozygous mutations in SPARC can give rise to severe bone fragility in humans. PMID:26027498

  1. 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. © 2013 Wiley Periodicals, Inc.

  2. Hexosamine Biosynthetic Pathway Mutations Cause Neuromuscular Transmission Defect

    Science.gov (United States)

    Senderek, Jan; Müller, Juliane S.; Dusl, Marina; Strom, Tim M.; Guergueltcheva, Velina; Diepolder, Irmgard; Laval, Steven H.; Maxwell, Susan; Cossins, Judy; Krause, Sabine; Muelas, Nuria; Vilchez, Juan J.; Colomer, Jaume; Mallebrera, Cecilia Jimenez; Nascimento, Andres; Nafissi, Shahriar; Kariminejad, Ariana; Nilipour, Yalda; Bozorgmehr, Bita; Najmabadi, Hossein; Rodolico, Carmelo; Sieb, Jörn P.; Steinlein, Ortrud K.; Schlotter, Beate; Schoser, Benedikt; Kirschner, Janbernd; Herrmann, Ralf; Voit, Thomas; Oldfors, Anders; Lindbergh, Christopher; Urtizberea, Andoni; von der Hagen, Maja; Hübner, Angela; Palace, Jacqueline; Bushby, Kate; Straub, Volker; Beeson, David; Abicht, Angela; Lochmüller, Hanns

    2011-01-01

    Neuromuscular junctions (NMJs) are synapses that transmit impulses from motor neurons to skeletal muscle fibers leading to muscle contraction. Study of hereditary disorders of neuromuscular transmission, termed congenital myasthenic syndromes (CMS), has helped elucidate fundamental processes influencing development and function of the nerve-muscle synapse. Using genetic linkage, we find 18 different biallelic mutations in the gene encoding glutamine-fructose-6-phosphate transaminase 1 (GFPT1) in 13 unrelated families with an autosomal recessive CMS. Consistent with these data, downregulation of the GFPT1 ortholog gfpt1 in zebrafish embryos altered muscle fiber morphology and impaired neuromuscular junction development. GFPT1 is the key enzyme of the hexosamine pathway yielding the amino sugar UDP-N-acetylglucosamine, an essential substrate for protein glycosylation. Our findings provide further impetus to study the glycobiology of NMJ and synapses in general. PMID:21310273

  3. Review and update of mutations causing Waardenburg syndrome.

    Science.gov (United States)

    Pingault, Véronique; Ente, Dorothée; Dastot-Le Moal, Florence; Goossens, Michel; Marlin, Sandrine; Bondurand, Nadège

    2010-04-01

    Waardenburg syndrome (WS) is characterized by the association of pigmentation abnormalities, including depigmented patches of the skin and hair, vivid blue eyes or heterochromia irides, and sensorineural hearing loss. However, other features such as dystopia canthorum, musculoskeletal abnormalities of the limbs, Hirschsprung disease, or neurological defects are found in subsets of patients and used for the clinical classification of WS. Six genes are involved in this syndrome: PAX3 (encoding the paired box 3 transcription factor), MITF (microphthalmia-associated transcription factor), EDN3 (endothelin 3), EDNRB (endothelin receptor type B), SOX10 (encoding the Sry bOX10 transcription factor), and SNAI2 (snail homolog 2), with different frequencies. In this review we provide an update on all WS genes and set up mutation databases, summarize molecular and functional data available for each of them, and discuss the applications in diagnostics and genetic counseling. (c) 2010 Wiley-Liss, Inc.

  4. De novo mutations in ATP1A3 cause alternating hemiplegia of childhood

    Science.gov (United States)

    Heinzen, Erin L.; Swoboda, Kathryn J.; Hitomi, Yuki; Gurrieri, Fiorella; Nicole, Sophie; de Vries, Boukje; Tiziano, F. Danilo; Fontaine, Bertrand; Walley, Nicole M.; Heavin, Sinéad; Panagiotakaki, Eleni; Fiori, Stefania; Abiusi, Emanuela; Di Pietro, Lorena; Sweney, Matthew T.; Newcomb, Tara M.; Viollet, Louis; Huff, Chad; Jorde, Lynn B.; Reyna, Sandra P.; Murphy, Kelley J.; Shianna, Kevin V.; Gumbs, Curtis E.; Little, Latasha; Silver, Kenneth; Ptác̆ek, Louis J.; Haan, Joost; Ferrari, Michel D.; Bye, Ann M.; Herkes, Geoffrey K.; Whitelaw, Charlotte M.; Webb, David; Lynch, Bryan J.; Uldall, Peter; King, Mary D.; Scheffer, Ingrid E.; Neri, Giovanni; Arzimanoglou, Alexis; van den Maagdenberg, Arn M.J.M.; Sisodiya, Sanjay M.; Mikati, Mohamad A.; Goldstein, David B.; Nicole, Sophie; Gurrieri, Fiorella; Neri, Giovanni; de Vries, Boukje; Koelewijn, Stephany; Kamphorst, Jessica; Geilenkirchen, Marije; Pelzer, Nadine; Laan, Laura; Haan, Joost; Ferrari, Michel; van den Maagdenberg, Arn; Zucca, Claudio; Bassi, Maria Teresa; Franchini, Filippo; Vavassori, Rosaria; Giannotta, Melania; Gobbi, Giuseppe; Granata, Tiziana; Nardocci, Nardo; De Grandis, Elisa; Veneselli, Edvige; Stagnaro, Michela; Gurrieri, Fiorella; Neri, Giovanni; Vigevano, Federico; Panagiotakaki, Eleni; Oechsler, Claudia; Arzimanoglou, Alexis; Nicole, Sophie; Giannotta, Melania; Gobbi, Giuseppe; Ninan, Miriam; Neville, Brian; Ebinger, Friedrich; Fons, Carmen; Campistol, Jaume; Kemlink, David; Nevsimalova, Sona; Laan, Laura; Peeters-Scholte, Cacha; van den Maagdenberg, Arn; Casaer, Paul; Casari, Giorgio; Sange, Guenter; Spiel, Georg; Boneschi, Filippo Martinelli; Zucca, Claudio; Bassi, Maria Teresa; Schyns, Tsveta; Crawley, Francis; Poncelin, Dominique; Vavassori, Rosaria

    2012-01-01

    Alternating hemiplegia of childhood (AHC) is a rare, severe neurodevelopmental syndrome characterized by recurrent hemiplegic episodes and distinct neurologic manifestations. AHC is usually a sporadic disorder with unknown etiology. Using exome sequencing of seven patients with AHC, and their unaffected parents, we identified de novo nonsynonymous mutations in ATP1A3 in all seven AHC patients. Subsequent sequence analysis of ATP1A3 in 98 additional patients revealed that 78% of AHC cases have a likely causal ATP1A3 mutation, including one inherited mutation in a familial case of AHC. Remarkably, six ATP1A3 mutations explain the majority of patients, including one observed in 36 patients. Unlike ATP1A3 mutations that cause rapid-onset-dystonia-parkinsonism, AHC-causing mutations revealed consistent reductions in ATPase activity without effects on protein expression. This work identifies de novo ATP1A3 mutations as the primary cause of AHC, and offers insight into disease pathophysiology by expanding the spectrum of phenotypes associated with mutations in this gene. PMID:22842232

  5. Characterization of mutations causing rifampicin and isoniazid resistance of Mycobacterium tuberculosis in Syria.

    Science.gov (United States)

    Madania, Ammar; Habous, Maya; Zarzour, Hana; Ghoury, Ifad; Hebbo, Barea

    2012-01-01

    In order to characterize mutations causing rifampicin and isoniazid resistance of M. tuberculosis in Syria, 69 rifampicin resistant (Rif(r)) and 72 isoniazid resistant (Inh(r)) isolates were screened for point mutations in hot spots of the rpoB, katG and inhA genes by DNA sequencing and real time PCR. Of 69 Rif(r) isolates, 62 (90%) had mutations in the rifampin resistance determining region (RRDR) of the rpoB gene, with codons 531 (61%), 526 (13%), and 516 (8.7%) being the most commonly mutated. We found two new mutations (Asp516Thr and Ser531Gly) described for the first time in the rpoB-RRDR in association with rifampicin resistance. Only one mutation (Ile572Phe) was found outside the rpoB-RRDR. Of 72 Inh(r) strains, 30 (41.6%) had a mutation in katGcodon315 (with Ser315Thr being the predominant alteration), and 23 (32%) harbored the inhA(-15C-->T) mutation. While the general pattern of rpoB-RRDR and katG mutations reflected those found worldwide, the prevalence of the inhA(-15C-->T mutation was above the value found in most other countries, emphasizing the great importance of testing the inhA(-15C-->T) mutation for prediction of isoniazid resistance in Syria. Sensitivity of a rapid test using real time PCR and 3'-Minor groove binder (MGB) probes in detecting Rif(r) and Inh(r) isolates was 90% and 69.4%, respectively. This demonstrates that a small set of MGB-probes can be used in real time PCR in order to detect most mutations causing resistance to rifampicin and isoniazid.

  6. Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes

    DEFF Research Database (Denmark)

    Schubert, J.; Siekierska, A.; Langlois, M.

    2014-01-01

    Febrile seizures affect 2-4% of all children(1) and have a strong genetic component(2). Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2)(3-5) have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encoding...... syntaxin-1B(6), that are associated with both febrile seizures and epilepsy. Whole-exome sequencing in independent large pedigrees(7,8) identified cosegregating STX1B mutations predicted to cause an early truncation or an in-frame insertion or deletion. Three additional nonsense or missense mutations....... Wild-type human syntaxin-1B but not a mutated protein rescued the effects of stx1b knockdown in zebrafish. Our results thus implicate STX1B and the presynaptic release machinery in fever-associated epilepsy syndromes....

  7. A frame-shift mutation of PMS2 is a widespread cause of Lynch syndrome

    DEFF Research Database (Denmark)

    Clendenning, Mark; Senter, Leigha; Hampel, Heather

    2008-01-01

    BACKGROUND: When compared to the other mismatch repair genes involved in Lynch syndrome, the identification of mutations within PMS2 has been limited (syndrome cases...... are caused by PMS2. This disparity is primarily due to complications in the study of this gene caused by interference from pseudogene sequences. METHODS: Using a recently developed method for detecting PMS2 specific mutations, we have screened 99 patients who are likely candidates for PMS2 mutations based...... on immunohistochemical analysis. RESULTS: We have identified a frequently occurring frame-shift mutation (c.736_741del6ins11) in 12 ostensibly unrelated Lynch syndrome patients (20% of patients we have identified with a deleterious mutation in PMS2, n=61). These individuals all display the rare allele (population...

  8. Mutations in the SPG7 gene cause chronic progressive external ophthalmoplegia through disordered mitochondrial DNA maintenance.

    Science.gov (United States)

    Pfeffer, Gerald; Gorman, Gráinne S; Griffin, Helen; Kurzawa-Akanbi, Marzena; Blakely, Emma L; Wilson, Ian; Sitarz, Kamil; Moore, David; Murphy, Julie L; Alston, Charlotte L; Pyle, Angela; Coxhead, Jon; Payne, Brendan; Gorrie, George H; Longman, Cheryl; Hadjivassiliou, Marios; McConville, John; Dick, David; Imam, Ibrahim; Hilton, David; Norwood, Fiona; Baker, Mark R; Jaiser, Stephan R; Yu-Wai-Man, Patrick; Farrell, Michael; McCarthy, Allan; Lynch, Timothy; McFarland, Robert; Schaefer, Andrew M; Turnbull, Douglass M; Horvath, Rita; Taylor, Robert W; Chinnery, Patrick F

    2014-05-01

    Despite being a canonical presenting feature of mitochondrial disease, the genetic basis of progressive external ophthalmoplegia remains unknown in a large proportion of patients. Here we show that mutations in SPG7 are a novel cause of progressive external ophthalmoplegia associated with multiple mitochondrial DNA deletions. After excluding known causes, whole exome sequencing, targeted Sanger sequencing and multiplex ligation-dependent probe amplification analysis were used to study 68 adult patients with progressive external ophthalmoplegia either with or without multiple mitochondrial DNA deletions in skeletal muscle. Nine patients (eight probands) were found to carry compound heterozygous SPG7 mutations, including three novel mutations: two missense mutations c.2221G>A; p.(Glu741Lys), c.2224G>A; p.(Asp742Asn), a truncating mutation c.861dupT; p.Asn288*, and seven previously reported mutations. We identified a further six patients with single heterozygous mutations in SPG7, including two further novel mutations: c.184-3C>T (predicted to remove a splice site before exon 2) and c.1067C>T; p.(Thr356Met). The clinical phenotype typically developed in mid-adult life with either progressive external ophthalmoplegia/ptosis and spastic ataxia, or a progressive ataxic disorder. Dysphagia and proximal myopathy were common, but urinary symptoms were rare, despite the spasticity. Functional studies included transcript analysis, proteomics, mitochondrial network analysis, single fibre mitochondrial DNA analysis and deep re-sequencing of mitochondrial DNA. SPG7 mutations caused increased mitochondrial biogenesis in patient muscle, and mitochondrial fusion in patient fibroblasts associated with the clonal expansion of mitochondrial DNA mutations. In conclusion, the SPG7 gene should be screened in patients in whom a disorder of mitochondrial DNA maintenance is suspected when spastic ataxia is prominent. The complex neurological phenotype is likely a result of the clonal

  9. Mutations in repeating structural motifs of tropomyosin cause gain of function in skeletal muscle myopathy patients.

    Science.gov (United States)

    Marston, Steven; Memo, Massimiliano; Messer, Andrew; Papadaki, Maria; Nowak, Kristen; McNamara, Elyshia; Ong, Royston; El-Mezgueldi, Mohammed; Li, Xiaochuan; Lehman, William

    2013-12-15

    The congenital myopathies include a wide spectrum of clinically, histologically and genetically variable neuromuscular disorders many of which are caused by mutations in genes for sarcomeric proteins. Some congenital myopathy patients have a hypercontractile phenotype. Recent functional studies demonstrated that ACTA1 K326N and TPM2 ΔK7 mutations were associated with hypercontractility that could be explained by increased myofibrillar Ca(2+) sensitivity. A recent structure of the complex of actin and tropomyosin in the relaxed state showed that both these mutations are located in the actin-tropomyosin interface. Tropomyosin is an elongated molecule with a 7-fold repeated motif of around 40 amino acids corresponding to the 7 actin monomers it interacts with. Actin binds to tropomyosin electrostatically at two points, through Asp25 and through a cluster of amino acids that includes Lys326, mutated in the gain-of-function mutation. Asp25 interacts with tropomyosin K6, next to K7 that was mutated in the other gain-of-function mutation. We identified four tropomyosin motifs interacting with Asp25 (K6-K7, K48-K49, R90-R91 and R167-K168) and three E-E/D-K/R motifs interacting with Lys326 (E139, E181 and E218), and we predicted that the known skeletal myopathy mutations ΔK7, ΔK49, R91G, ΔE139, K168E and E181K would cause a gain of function. Tests by an in vitro motility assay confirmed that these mutations increased Ca(2+) sensitivity, while mutations not in these motifs (R167H, R244G) decreased Ca(2+) sensitivity. The work reported here explains the molecular mechanism for 6 out of 49 known disease-causing mutations in the TPM2 and TPM3 genes, derived from structural data of the actin-tropomyosin interface.

  10. Molecular Basis of DFNB73: Mutations of BSND Can Cause Nonsyndromic Deafness or Bartter Syndrome

    Science.gov (United States)

    Riazuddin, Saima; Anwar, Saima; Fischer, Martin; Ahmed, Zubair M.; Khan, Shahid Y.; Janssen, Audrey G.H.; Zafar, Ahmad U.; Scholl, Ute; Husnain, Tayyab; Belyantseva, Inna A.; Friedman, Penelope L.; Riazuddin, Sheikh; Friedman, Thomas B.; Fahlke, Christoph

    2009-01-01

    BSND encodes barttin, an accessory subunit of renal and inner ear chloride channels. To date, all mutations of BSND have been shown to cause Bartter syndrome type IV, characterized by significant renal abnormalities and deafness. We identified a BSND mutation (p.I12T) in four kindreds segregating nonsyndromic deafness linked to a 4.04-cM interval on chromosome 1p32.3. The functional consequences of p.I12T differ from BSND mutations that cause renal failure and deafness in Bartter syndrome type IV. p.I12T leaves chloride channel function unaffected and only interferes with chaperone function of barttin in intracellular trafficking. This study provides functional data implicating a hypomorphic allele of BSND as a cause of apparent nonsyndromic deafness. We demonstrate that BSND mutations with different functional consequences are the basis for either syndromic or nonsyndromic deafness. PMID:19646679

  11. Fifteen novel FBN1 mutations causing Marfan syndrome detected by heteroduplex analysis of genomic amplicons

    Energy Technology Data Exchange (ETDEWEB)

    Nijbroek, G.; Sood, S.; McIntosh, I. [John Hopkins Univ. School of Medicine, Baltimore, MD (United States)] [and others

    1995-07-01

    Mutations in the gene encoding fibrillin-1 (FBN1), a component of the extracellular microfibril, cause the Marfan syndrome (MFS). This statement is supported by the observations that the classic Marfan phenotype cosegregates with intragenic and/or flanking marker alleles in all families tested and that a significant number of FBN1 mutations have been identified in affected individuals. We have now devised a method to screen the entire coding sequence and flanking splice junctions of FBN1. On completion for a panel of nine probands with classic MFS, six new mutations were identified that accounted for disease in seven (78%) of nine patients. Nine additional new mutations have been characterized in the early stages of a larger screening project. These 15 mutations were equally distributed throughout the gene and, with one exception, were specific to single families. One-third of mutations created premature termination codons, and 6 of 15 substituted residues with putative significance for calcium finding to epidermal growth factor (EGF)-like domains. Mutations causing severe and rapidly progressive disease that presents in the neonatal period can occur in a larger region of the gene than previously demonstrated, and the nature of the mutation is as important a determinant as its location, in predisposing to this phenotype. 56 refs., 5 figs., 3 tabs.

  12. A new F-box protein 7 gene mutation causing typical Parkinson's disease.

    Science.gov (United States)

    Lohmann, Ebba; Coquel, Anne-Sophie; Honoré, Aurélie; Gurvit, Hakan; Hanagasi, Hasmet; Emre, Murat; Leutenegger, Anne L; Drouet, Valérie; Sahbatou, Mourad; Guven, Gamze; Erginel-Unaltuna, Nihan; Deleuze, Jean-Francois; Lesage, Suzanne; Brice, Alexis

    2015-07-01

    Recessive mutations in the F-box protein 7 gene (FBXO7; PARK15) have been identified as a cause of the parkinsonian-pyramidal syndrome. Here, we report clinical and genetic findings in a Turkish family with novel FBXO7 mutations. Whole exome and targeted Sanger sequencing were performed for genetic analysis in a family with two members affected by Parkinson's disease (PD). All family members underwent detailed clinical, mental, and neurological examination. The new p.L34R (c.101 T>G) FBXO7 mutation was detected in a homozygous state in two Turkish sibs with typical levodopa-responsive PD. This is the first time a FBXO7 mutation has been identified that causes a phenotype compatible with typical idiopathic PD and presents with some of its common nonmotor features, such as rapid eye movement sleep behavior disorder, depression, and anxiety. © 2015 International Parkinson and Movement Disorder Society.

  13. Presymptomatic generalized brain atrophy in frontotemporal dementia caused by CHMP2B mutation

    DEFF Research Database (Denmark)

    Rohrer, Jonathan D; Ahsan, R Laila; Isaacs, Adrian M

    2009-01-01

    BACKGROUND/AIMS: CHMP2B mutations are a rare cause of familial frontotemporal dementia (FTD). The clinical syndrome is dominated by personality change and behavioural symptoms, but language, memory, calculation and praxis impairments are also seen early in the course of the disease. There are no ......BACKGROUND/AIMS: CHMP2B mutations are a rare cause of familial frontotemporal dementia (FTD). The clinical syndrome is dominated by personality change and behavioural symptoms, but language, memory, calculation and praxis impairments are also seen early in the course of the disease...... gene mutation carriers. CONCLUSIONS: This finding suggests that mutations in CHMP2B have widespread effects throughout the brain, leading to a neuro-anatomical signature distinct from other diseases in the frontotemporal lobar degeneration spectrum....

  14. No muscle involvement in myoclonus-dystonia caused by epsilon-sarcoglycan gene mutations1

    DEFF Research Database (Denmark)

    Hjermind, L.E.; Vissing, J.; Asmus, F.

    2008-01-01

    homologous and may substitute for one-another in different tissues. We therefore investigated whether mutations in SGCE also cause abnormalities of skeletal and myocardial muscle. Six patients with clinically and genetically verified M-D and no signs of limb-girdle muscular dystrophy were included. Skeletal......Mutations in the epsilon-sarcoglycan gene (SGCE) can cause autosomal dominant inherited myoclonus-dystonia (M-D). Defects in other sarcoglycans; alpha-, beta-, gamma-, and delta can cause autosomal recessive inherited limb girdle muscular dystrophies. epsilon- and alpha-sarcoglycans are very...

  15. SAAMBE: Webserver to Predict the Charge of Binding Free Energy Caused by Amino Acids Mutations.

    Science.gov (United States)

    Petukh, Marharyta; Dai, Luogeng; Alexov, Emil

    2016-04-12

    Predicting the effect of amino acid substitutions on protein-protein affinity (typically evaluated via the change of protein binding free energy) is important for both understanding the disease-causing mechanism of missense mutations and guiding protein engineering. In addition, researchers are also interested in understanding which energy components are mostly affected by the mutation and how the mutation affects the overall structure of the corresponding protein. Here we report a webserver, the Single Amino Acid Mutation based change in Binding free Energy (SAAMBE) webserver, which addresses the demand for tools for predicting the change of protein binding free energy. SAAMBE is an easy to use webserver, which only requires that a coordinate file be inputted and the user is provided with various, but easy to navigate, options. The user specifies the mutation position, wild type residue and type of mutation to be made. The server predicts the binding free energy change, the changes of the corresponding energy components and provides the energy minimized 3D structure of the wild type and mutant proteins for download. The SAAMBE protocol performance was tested by benchmarking the predictions against over 1300 experimentally determined changes of binding free energy and a Pearson correlation coefficient of 0.62 was obtained. How the predictions can be used for discriminating disease-causing from harmless mutations is discussed. The webserver can be accessed via http://compbio.clemson.edu/saambe_webserver/.

  16. Reciprocal sign epistasis between frequently experimentally evolved adaptive mutations causes a rugged fitness landscape.

    Directory of Open Access Journals (Sweden)

    Daniel J Kvitek

    2011-04-01

    Full Text Available The fitness landscape captures the relationship between genotype and evolutionary fitness and is a pervasive metaphor used to describe the possible evolutionary trajectories of adaptation. However, little is known about the actual shape of fitness landscapes, including whether valleys of low fitness create local fitness optima, acting as barriers to adaptive change. Here we provide evidence of a rugged molecular fitness landscape arising during an evolution experiment in an asexual population of Saccharomyces cerevisiae. We identify the mutations that arose during the evolution using whole-genome sequencing and use competitive fitness assays to describe the mutations individually responsible for adaptation. In addition, we find that a fitness valley between two adaptive mutations in the genes MTH1 and HXT6/HXT7 is caused by reciprocal sign epistasis, where the fitness cost of the double mutant prohibits the two mutations from being selected in the same genetic background. The constraint enforced by reciprocal sign epistasis causes the mutations to remain mutually exclusive during the experiment, even though adaptive mutations in these two genes occur several times in independent lineages during the experiment. Our results show that epistasis plays a key role during adaptation and that inter-genic interactions can act as barriers between adaptive solutions. These results also provide a new interpretation on the classic Dobzhansky-Muller model of reproductive isolation and display some surprising parallels with mutations in genes often associated with tumors.

  17. A Novel Mutation in the EDAR Gene Causes Severe Autosomal Recessive Hypohidrotic Ectodermal Dysplasia

    DEFF Research Database (Denmark)

    Henningsen, Emil; Svendsen, Mathias Tiedemann; Lildballe, D. L.

    2014-01-01

    nasal discharge. The girl was the second born child of first-cousin immigrants from Northern Iraq. A novel homozygous mutation (c.84delC) in the EDAR gene was identified. This mutation most likely causes a frameshift in the protein product (p.S29fs*74). This results in abolition of all ectodysplasin......-mediated NF-kB signalling. This complete loss-of-function mutation likely accounts for the severe clinical abnormalities in ectodermal structures in the described patient. (C) 2014 Wiley Periodicals, Inc....

  18. A De Novo Mutation in Causes Generalized Dystonia in 2 Unrelated Children

    Directory of Open Access Journals (Sweden)

    Yasemin Gulcan Kurt MD

    2016-03-01

    Full Text Available Dystonia is often associated with the symmetrical basal ganglia lesions of Leigh syndrome. However, it has also been associated with mitochondrial ND mutations, with or without Leber hereditary optic neuropathy. The m.14459G>A mutation in ND6 causes dystonia with or without familial Leber hereditary optic neuropathy. We report heteroplasmic 14459G>A mutations in 2 unrelated children with nonmaternally inherited generalized dystonia and showing bilateral magnetic resonance imaging lesions in nucleus pallidus and putamen. Both children have reached their teenage years, and they are intellectually active, despite their motor problems.

  19. A novel nonsense mutation in the WFS1 gene causes the Wolfram syndrome.

    Science.gov (United States)

    Noorian, Shahab; Savad, Shahram; Mohammadi, Davood Shah

    2016-05-01

    Wolfram syndrome is a rare autosomal recessive neurodegenerative disorder, which is mostly caused by mutations in the WFS1 gene. The WFS1 gene product, which is called wolframin, is thought to regulate the function of endoplasmic reticulum. The endoplasmic reticulum has a critical role in protein folding and material transportation within the cell or to the surface of the cell. Identification of new mutations in WFS1 gene will unravel the molecular pathology of WS. The aim of this case report study is to describe a novel mutation in exon 4 of the WFS1 gene (c.330C>A) in a 9-year-old boy with WS.

  20. Two missense mutations in KCNQ1 cause pituitary hormone deficiency and maternally inherited gingival fibromatosis

    DEFF Research Database (Denmark)

    Tommiska, Johanna; Känsäkoski, Johanna; Skibsbye, Lasse

    2017-01-01

    Familial growth hormone deficiency provides an opportunity to identify new genetic causes of short stature. Here we combine linkage analysis with whole-genome resequencing in patients with growth hormone deficiency and maternally inherited gingival fibromatosis. We report that patients from three...... associated with maternally inherited gingival fibromatosis is an allelic disorder with cardiac arrhythmia syndromes caused by KCNQ1 mutations....

  1. Novel CACNA1S mutation causes autosomal dominant hypokalemic periodic paralysis in a Chinese family.

    Science.gov (United States)

    Wang, Qiufen; Liu, Mugen; Xu, Chunsheng; Tang, Zhaohui; Liao, Yuhua; Du, Rong; Li, Wei; Wu, Xiaoyan; Wang, Xu; Liu, Ping; Zhang, Xianqin; Zhu, Jianfang; Ren, Xiang; Ke, Tie; Wang, Qing; Yang, Junguo

    2005-03-01

    Hypokalemic periodic paralysis (HypoPP) is an autosomal dominant disorder which is characterized by periodic attacks of muscle weakness associated with a decrease in the serum potassium level. The skeletal muscle calcium channel alpha-subunit gene CACNA1S is a major disease-causing gene for HypoPP, however, only three specific HypoPP-causing mutations, Arg528His, Arg1,239His and Arg1,239Gly, have been identified in CACNA1S to date. In this study, we studied a four-generation Chinese family with HypoPP with 43 living members and 19 affected individuals. Linkage analysis showed that the causative mutation in the family is linked to the CACNA1S gene with a LOD score of 6.7. DNA sequence analysis revealed a heterozygous C to G transition at nucleotide 1,582, resulting in a novel 1,582C-->G (Arg528Gly) mutation. The Arg528Gly mutation co-segregated with all affected individuals in the family, and was not present in 200 matched normal controls. The penetrance of the Arg528Gly mutation was complete in male mutation carriers, however, a reduced penetrance of 83% (10/12) was observed in female carriers. No differences were detected for age-at-onset and severity of the disease (frequency of symptomatic attacks per year) between male and female patients. Oral intake of KCl is effective in blocking the symptomatic attacks. This study identifies a novel Arg528Gly mutation in the CACNA1S gene that causes HypoPP in a Chinese family, expands the spectrum of mutations causing HypoPP, and demonstrates a gender difference in the penetrance of the disease.

  2. Mutations in SYNGAP1 Cause Intellectual Disability, Autism, and a Specific Form of Epilepsy by Inducing Haploinsufficiency

    DEFF Research Database (Denmark)

    Berryer, Martin H; Hamdan, Fadi F; Klitten, Laura L

    2013-01-01

    De novo mutations in SYNGAP1, which codes for a RAS/RAP GTP-activating protein, cause nonsyndromic intellectual disability (NSID). All disease-causing point mutations identified until now in SYNGAP1 are truncating, raising the possibility of an association between this type of mutations and NSID...

  3. The Lebanese mutation as an important cause of familial hypercholesterolemia in Brazil

    Directory of Open Access Journals (Sweden)

    Alberto F.L.

    1999-01-01

    Full Text Available Familial hypercholesterolemia (FH is a common autosomal disorder that affects about one in 500 individuals in most Western populations and is caused by a defect in the low-density-lipoprotein receptor (LDLr gene. In this report we determined the molecular basis of FH in 59 patients from 31 unrelated Brazilian families. All patients were screened for the Lebanese mutation, gross abnormalities of the LDLr gene, and the point mutation in the codon 3500 of the apolipoprotein B-100 gene. None of the 59 patients presented the apoB-3500 mutation, suggesting that familial defective ApoB-100 (FDB is not a major cause of inherited hypercholesterolemia in Brazil. A novel 4-kb deletion in the LDLr gene, spanning from intron 12 to intron 14, was characterized in one family. Both 5' and 3' breakpoint regions were located within Alu repetitive sequences, which are probably involved in the crossing over that generated this rearrangement. The Lebanese mutation was detected in 9 of the 31 families, always associated with Arab ancestry. Two different LDLr gene haplotypes were demonstrated in association with the Lebanese mutation. Our results suggest the importance of the Lebanese mutation as a cause of FH in Brazil and by analogy the same feature may be expected in other countries with a large Arab population, such as North American and Western European countries.

  4. Cap +1 mutation; an unsuspected cause of beta thalassaemia transmission in Pakistan

    Directory of Open Access Journals (Sweden)

    Sadia Usman Babar

    2009-12-01

    Full Text Available Objective: Thalassemia is one of the most common genetic disorders worldwide. Cap +1 mutation which causes ‘silent beta thalassemia’ is present around all ethnic groups of Pakistan. This study was designed to detect the frequency of Cap+1 mutation in Pakistani Population.Materials and Methods: Molecular genetic for Cap+1 beta thalassemic mutation was done by extracting DNA from whole blood by using Genomic DNA Purification Kit (Gentra system USA. Amplification Refractory Mutation System (ARMS primers were designed for detection of normal and mutant DNA.Basic hematological parameters were performed by using automated analyzer (Sysmex KX-21. Cellulose acetate hemoglobin electrophoresis was done by using semi-automated technique (INTERLAB Roma Microtech Series Electrophoresis system 4.23. Results: The frequency of Cap+1 mutation was observed 5% (10/200 in targeted thalassemic families (having patients with beta-thalassemia intermedia while its frequency was observed 2% (12/600 in total thalassemic genes in Pakistani population. Conclusion: Cap+1 (A-C is a silent mutation and it has very minimum effect on beta globin synthesis because of which it produces very less clinical severity and certain important laboratory diagnostic tests like basic hematological parameters and Hb A2 levels are also remain in normal range. Therefore individuals with Cap+1 mutation may produce children with beta-thalassemia intermedia if they marry an individual with beta-thalassemia minor. Cap+1 (A-C mutation is an unsuspected cause of beta thalassemia transmission in Pakistani population. This mutation can identify at molecular level. As this molecular defect is difficult to diagnose in Laboratory with routine laboratory tests because of that it has become a serious hindrance for thalassemia prevention program in Pakistan.

  5. Mutations in noncoding regions of GJB1 are a major cause of X-linked CMT

    Science.gov (United States)

    Tomaselli, Pedro J.; Rossor, Alexander M.; Horga, Alejandro; Jaunmuktane, Zane; Carr, Aisling; Saveri, Paola; Piscosquito, Giuseppe; Pareyson, Davide; Laura, Matilde; Blake, Julian C.; Poh, Roy; Polke, James; Houlden, Henry

    2017-01-01

    Objective: To determine the prevalence and clinical and genetic characteristics of patients with X-linked Charcot-Marie-Tooth disease (CMT) due to mutations in noncoding regions of the gap junction β-1 gene (GJB1). Methods: Mutations were identified by bidirectional Sanger sequence analysis of the 595 bases of the upstream promoter region, and 25 bases of the 3′ untranslated region (UTR) sequence in patients in whom mutations in the coding region had been excluded. Clinical and neurophysiologic data were retrospectively collected. Results: Five mutations were detected in 25 individuals from 10 kindreds representing 11.4% of all cases of CMTX1 diagnosed in our neurogenetics laboratory between 1996 and 2016. Four pathogenic mutations, c.-17G>A, c.-17+1G>T, c.-103C>T, and c.-146-90_146-89insT were detected in the 5′UTR. A novel mutation, c.*15C>T, was detected in the 3′ UTR of GJB1 in 2 unrelated families with CMTX1 and is the first pathogenic mutation in the 3′UTR of any myelin-associated CMT gene. Mutations segregated with the phenotype, were at sites predicted to be pathogenic, and were not present in the normal population. Conclusions: Mutations in noncoding DNA are a major cause of CMTX1 and highlight the importance of mutations in noncoding DNA in human disease. Next-generation sequencing platforms for use in inherited neuropathy should therefore include coverage of these regions. PMID:28283593

  6. Somatic USP8 Gene Mutations Are a Common Cause of Pediatric Cushing Disease.

    Science.gov (United States)

    Faucz, Fabio R; Tirosh, Amit; Tatsi, Christina; Berthon, Annabel; Hernández-Ramírez, Laura C; Settas, Nikolaos; Angelousi, Anna; Correa, Ricardo; Papadakis, Georgios Z; Chittiboina, Prashant; Quezado, Martha; Pankratz, Nathan; Lane, John; Dimopoulos, Aggeliki; Mills, James L; Lodish, Maya; Stratakis, Constantine A

    2017-08-01

    Somatic mutations in the ubiquitin-specific protease 8 (USP8) gene have been recently identified as the most common genetic alteration in patients with Cushing disease (CD). However, the frequency of these mutations in the pediatric population has not been extensively assessed. We investigated the status of the USP8 gene at the somatic level in a cohort of pediatric patients with corticotroph adenomas. The USP8 gene was fully sequenced in both germline and tumor DNA samples from 42 pediatric patients with CD. Clinical, biochemical, and imaging data were compared between patients with and without somatic USP8 mutations. Five different USP8 mutations (three missense, one frameshift, and one in-frame deletion) were identified in 13 patients (31%), all of them located in exon 14 at the previously described mutational hotspot, affecting the 14-3-3 binding motif of the protein. Patients with somatic mutations were older at disease presentation [mean 5.1 ± 2.1 standard deviation (SD) vs 13.1 ± 3.6 years, P = 0.03]. Levels of urinary free cortisol, midnight serum cortisol, and adrenocorticotropic hormone, as well as tumor size and frequency of invasion of the cavernous sinus, were not significantly different between the two groups. However, patients harboring somatic USP8 mutations had a higher likelihood of recurrence compared with patients without mutations (46.2% vs 10.3%, P = 0.009). Somatic USP8 gene mutations are a common cause of pediatric CD. Patients harboring a somatic mutation had a higher likelihood of tumor recurrence, highlighting the potential importance of this molecular defect for the disease prognosis and the development of targeted therapeutic options. Copyright © 2017 Endocrine Society

  7. Mutations in MME cause an autosomal‐recessive Charcot–Marie–Tooth disease type 2

    Science.gov (United States)

    Higuchi, Yujiro; Hashiguchi, Akihiro; Yuan, Junhui; Yoshimura, Akiko; Mitsui, Jun; Ishiura, Hiroyuki; Tanaka, Masaki; Ishihara, Satoshi; Tanabe, Hajime; Nozuma, Satoshi; Okamoto, Yuji; Matsuura, Eiji; Ohkubo, Ryuichi; Inamizu, Saeko; Shiraishi, Wataru; Yamasaki, Ryo; Ohyagi, Yasumasa; Kira, Jun‐ichi; Oya, Yasushi; Yabe, Hayato; Nishikawa, Noriko; Tobisawa, Shinsuke; Matsuda, Nozomu; Masuda, Masayuki; Kugimoto, Chiharu; Fukushima, Kazuhiro; Yano, Satoshi; Yoshimura, Jun; Doi, Koichiro; Nakagawa, Masanori; Morishita, Shinichi; Tsuji, Shoji

    2016-01-01

    Objective The objective of this study was to identify new causes of Charcot–Marie–Tooth (CMT) disease in patients with autosomal‐recessive (AR) CMT. Methods To efficiently identify novel causative genes for AR‐CMT, we analyzed 303 unrelated Japanese patients with CMT using whole‐exome sequencing and extracted recessive variants/genes shared among multiple patients. We performed mutation screening of the newly identified membrane metalloendopeptidase (MME) gene in 354 additional patients with CMT. We clinically, genetically, pathologically, and radiologically examined 10 patients with the MME mutation. Results We identified recessive mutations in MME in 10 patients. The MME gene encodes neprilysin (NEP), which is well known to be one of the most prominent beta‐amyloid (Aβ)‐degrading enzymes. All patients had a similar phenotype consistent with late‐onset axonal neuropathy. They showed muscle weakness, atrophy, and sensory disturbance in the lower extremities. All the MME mutations could be loss‐of‐function mutations, and we confirmed a lack/decrease of NEP protein expression in a peripheral nerve. No patients showed symptoms of dementia, and 1 patient showed no excess Aβ in Pittsburgh compound‐B positron emission tomography imaging. Interpretation Our results indicate that loss‐of‐function MME mutations are the most frequent cause of adult‐onset AR‐CMT2 in Japan, and we propose that this new disease should be termed AR‐CMT2T. A loss‐of‐function MME mutation did not cause early‐onset Alzheimer's disease. Identifying the MME mutation responsible for AR‐CMT could improve the rate of molecular diagnosis and the understanding of the molecular mechanisms of CMT. Ann Neurol 2016;79:659–672 PMID:26991897

  8. FAM83H mutations cause ADHCAI and alter intracellular protein localization.

    Science.gov (United States)

    Lee, S-K; Lee, K-E; Jeong, T-S; Hwang, Y-H; Kim, S; Hu, J C-C; Simmer, J P; Kim, J-W

    2011-03-01

    Mutations in a family with sequence similarity 83 member H (FAM83H) cause autosomal-dominant hypocalcification amelogenesis imperfecta (ADH CAI). All FAM83H ADHCAI-causing mutations terminate translation or shift the reading frame within the specific exon 5 segment that encodes from Ser(287) to Glu(694). Mutations near Glu(694) cause a milder, more localized phenotype. We identified disease-causing FAM83H mutations in two families with ADHCAI: family 1 (g.3115C>T, c.1993 C>T, p.Q665X) and family 2 (g.3151C>T, c.2029 C>T, p.Q677X). We also tested the hypothesis that truncation mutations alter the intracellular localization of FAM83H. Wild-type FAM83H and p.E694X mutant FAM83H fused to green fluorescent protein (GFP) localized in the cytoplasm of HEK293T cells, but the mutant FAM83H proteins (p.R325X, p.W460X, and p.Q677X) fused to GFP localized mainly in the nucleus with slight expression in the cytoplasm. We conclude that nuclear targeting of the truncated FAM83H protein contributes to the severe, generalized enamel phenotype.

  9. A functional alternative splicing mutation in AIRE gene causes autoimmune polyendocrine syndrome type 1.

    Directory of Open Access Journals (Sweden)

    Junyu Zhang

    Full Text Available Autoimmune polyendocrine syndrome type 1 (APS-1 is a rare autosomal recessive disease defined by the presence of two of the three conditions: mucocutaneous candidiasis, hypoparathyroidism, and Addison's disease. Loss-of-function mutations of the autoimmune regulator (AIRE gene have been linked to APS-1. Here we report mutational analysis and functional characterization of an AIRE mutation in a consanguineous Chinese family with APS-1. All exons of the AIRE gene and adjacent exon-intron sequences were amplified by PCR and subsequently sequenced. We identified a homozygous missense AIRE mutation c.463G>A (p.Gly155Ser in two siblings with different clinical features of APS-1. In silico splice-site prediction and minigene analysis were carried out to study the potential pathological consequence. Minigene splicing analysis and subsequent cDNA sequencing revealed that the AIRE mutation potentially compromised the recognition of the splice donor of intron 3, causing alternative pre-mRNA splicing by intron 3 retention. Furthermore, the aberrant AIRE transcript was identified in a heterozygous carrier of the c.463G>A mutation. The aberrant intron 3-retaining transcript generated a truncated protein (p.G155fsX203 containing the first 154 AIRE amino acids and followed by 48 aberrant amino acids. Therefore, our study represents the first functional characterization of the alternatively spliced AIRE mutation that may explain the pathogenetic role in APS-1.

  10. Identities and frequencies of mutations of the otoferlin gene (OTOF) causing DFNB9 deafness in Pakistan

    Science.gov (United States)

    Choi, BY; Ahmed, ZM; Riazuddin, S; Bhinder, MA; Shahzad, M; Husnain, T; Riazuddin, S; Griffith, AJ; Friedman, TB

    2012-01-01

    Mutations in OTOF, encoding otoferlin, cause non-syndromic recessive hearing loss. The goal of our study was to define the identities and frequencies of OTOF mutations in a model population. We screened a cohort of 557 large consanguineous Pakistani families segregating recessive, severe-to-profound, prelingual-onset deafness for linkage to DFNB9. There were 13 families segregating deafness consistent with linkage to markers for DFNB9. We analyzed the genomic nucleotide sequence of OTOF and detected probable pathogenic sequence variants among all 13 families. These include the previously reported nonsense mutation p.R708X and 10 novel variants: 3 nonsense mutations (p.R425X, p.W536X, and p.Y1603X), 1 frameshift (c.1103_1104delinsC), 1 single amino acid deletion (p.E766del) and 5 missense substitutions of conserved residues (p.L573R, p.A1090E, p.E1733K, p.R1856Q and p.R1939W). OTOF mutations thus account for deafness in 13 (2.3%) of 557 Pakistani families. This overall prevalence is similar, but the mutation spectrum is different from those for Western populations. In addition, we demonstrate the existence of an alternative splice isoform of OTOF expressed in the human cochlea. This isoform must be required for human hearing because it encodes a unique alternative C-terminus affected by some DFNB9 mutations. PMID:19250381

  11. Primary ciliary dyskinesia-causing mutations in Amish and Mennonite communities.

    Science.gov (United States)

    Ferkol, Thomas W; Puffenberger, Erik G; Lie, Hauw; Helms, Cynthia; Strauss, Kevin A; Bowcock, Anne; Carson, John L; Hazucha, Milan; Morton, D Holmes; Patel, Anand C; Leigh, Margaret W; Knowles, Michael R; Zariwala, Maimoona A

    2013-08-01

    To determine whether individuals with primary ciliary dyskinesia (PCD) from unrelated Amish and Mennonite families harbor a single and unique founder mutation. Subjects from Amish and Mennonite communities in several states were enrolled in the study. All subjects were clinically characterized, and nasal nitric oxide levels were measured. Nasal epithelial scrapings were collected from several subjects for ciliary ultrastructural analyses. DNA was isolated from patients with PCD and their unaffected first- and second-degree relatives. Genome-wide homozygosity mapping, linkage analyses, targeted mutation analyses, and exome sequencing were performed. All subjects from Old-Order Amish communities from Pennsylvania were homozygous for a nonsense mutant DNAH5 allele, c.4348C>T (p.Q1450X). Two affected siblings from an unrelated Mennonite family in Arkansas were homozygous for the same nonsense DNAH5 mutation. Children with PCD from an Amish family from Wisconsin had biallelic DNAH5 mutations, c.4348C>T (p.Q1450X) and c.10815delT (p.P3606HfsX23), and mutations in other genes associated with PCD were also identified in this community. The Amish and Mennonite subjects from geographically dispersed and socially isolated communities had the same founder DNAH5 mutation, owing to the common heritage of these populations. However, disease-causing mutations in other PCD-associated genes were also found in affected individuals in these communities, illustrating the genetic heterogeneity in this consanguineous population. Copyright © 2013 Mosby, Inc. All rights reserved.

  12. Mutations in SLC20A2 are a major cause of familial idiopathic basal ganglia calcification

    Science.gov (United States)

    Hsu, Sandy Chan; Sears, Renee L.; Lemos, Roberta R.; Quintáns, Beatriz; Huang, Alden; Spiteri, Elizabeth; Nevarez, Lisette; Mamah, Catherine; Zatz, Mayana; Pierce, Kerrie D.; Fullerton, Janice M.; Adair, John C.; Berner, Jon E.; Bower, Matthew; Brodaty, Henry; Carmona, Olga; Dobricić, Valerija; Fogel, Brent L.; García-Estevez, Daniel; Goldman, Jill; Goudreau, John L.; Hopfer, Suellen; Janković, Milena; Jaumà, Serge; Jen, Joanna C.; Kirdlarp, Suppachok; Klepper, Joerg; Kostić, Vladimir; Lang, Anthony E.; Linglart, Agnès; Maisenbacher, Melissa K.; Manyam, Bala V.; Mazzoni, Pietro; Miedzybrodzka, Zofia; Mitarnun, Witoon; Mitchell, Philip B.; Mueller, Jennifer; Novaković, Ivana; Paucar, Martin; Paulson, Henry; Simpson, Sheila A.; Svenningsson, Per; Tuite, Paul; Vitek, Jerrold; Wetchaphanphesat, Suppachok; Williams, Charles; Yang, Michele; Schofield, Peter R.; de Oliveira, João R. M.; Sobrido, María-Jesús

    2014-01-01

    Familial idiopathic basal ganglia calcification (IBGC) or Fahr’s disease is a rare neurodegenerative disorder characterized by calcium deposits in the basal ganglia and other brain regions, which is associated with neuropsychiatric and motor symptoms. Familial IBGC is genetically heterogeneous and typically transmitted in an autosomal dominant fashion. We performed a mutational analysis of SLC20A2, the first gene found to cause IBGC, to assess its genetic contribution to familial IBGC. We recruited 218 subjects from 29 IBGC-affected families of varied ancestry and collected medical history, neurological exam, and head CT scans to characterize each patient’s disease status. We screened our patient cohort for mutations in SLC20A2. Twelve novel (nonsense, deletions, missense, and splice site) potentially pathogenic variants, one synonymous variant, and one previously reported mutation were identified in 13 families. Variants predicted to be deleterious cosegregated with disease in five families. Three families showed nonsegregation with clinical disease of such variants, but retrospective review of clinical and neuroimaging data strongly suggested previous misclassification. Overall, mutations in SLC20A2 account for as many as 41 % of our familial IBGC cases. Our screen in a large series expands the catalog of SLC20A2 mutations identified to date and demonstrates that mutations in SLC20A2 are a major cause of familial IBGC. Non-perfect segregation patterns of predicted deleterious variants highlight the challenges of phenotypic assessment in this condition with highly variable clinical presentation. PMID:23334463

  13. Germinal mosaicism of PAX3 mutation caused Waardenburg syndrome type I.

    Science.gov (United States)

    Chen, Kaitian; Zhan, Yuan; Wu, Xuan; Zong, Ling; Jiang, Hongyan

    2018-01-01

    Waardenburg syndrome mutations are most often recurrent or de novo. The rate of familial recurrence is low and families with several affected children are extremely rare. In this study, we aimed to clarify the underlying hereditary cause of Waardenburg syndrome type I in two siblings in a Chinese family, with a mother affected by prelingual mild hearing loss and a father who was negative for clinical symptoms of Waardenburg syndrome and had a normal hearing threshold. Complete characteristic features of the family members were recorded and genetic sequencing and parent-child relationship analyses were performed. The two probands were found to share double mutations in the PAX3/GJB2 genes that caused concurrent hearing loss in Waardenburg syndrome type I. Their mother carried the GJB2 c.109G > A homozygous mutation; however, neither the novel PAX3 c.592delG mutation, nor the Waardenburg syndrome phenotype, was observed in either parent. These previously unreported digenic mutations in PAX3/GJB2 resulted in deafness associated with Waardenburg syndrome type I in this family. To our knowledge, this is the first report describing germinal mosaicism in Waardenburg syndrome. This concept is important because it complicates genetic counseling of this family regarding the risk of recurrence of the mutations in subsequent pregnancies. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. c.376G>A mutation in WFS1 gene causes Wolfram syndrome without deafness.

    Science.gov (United States)

    Safarpour Lima, Behnam; Ghaedi, Hamid; Daftarian, Narsis; Ahmadieh, Hamid; Jamshidi, Javad; Khorrami, Mehdi; Noroozi, Rezvan; Sohrabifar, Nasim; Assarzadegan, Farhad; Hesami, Omid; Taghavi, Shaghayegh; Ahmadifard, Azadeh; Atakhorrami, Minoo; Rahimi-Aliabadi, Simin; Shahmohammadibeni, Neda; Alehabib, Elham; Andarva, Monavvar; Darvish, Hossein; Emamalizadeh, Babak

    2016-02-01

    Wolfram syndrome is one of the rare autosomal recessive, progressive, neurodegenerative disorders, characterized by diabetes mellitus and optic atrophy. Several other features are observed in patients including deafness, ataxia, and peripheral neuropathy. A gene called WFS1 is identified on chromosome 4p, responsible for Wolfram syndrome. We investigated a family consisted of parents and 8 children, which 5 of them have been diagnosed for Wolfram syndrome. WFS1 gene in all family members was sequenced for causative mutations. A mutation (c.376G>A, p.A126T) was found in all affected members in homozygous state and in both parents in heterozygous state. The bioinformatics analysis showed the deleterious effects of this nucleotide change on the structure and function of the protein product. As all of the patients in the family showed the homozygote mutation, and parents were both heterozygote, this mutation is probably the cause of the disease. We identified this mutation in homozygous state for the first time as Wolfram syndrome causation. We also showed that this mutation probably doesn't cause deafness in affected individuals. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Loss of stability and hydrophobicity of presenilin 1 mutations causing Alzheimer's Disease

    DEFF Research Database (Denmark)

    Somavarapu, Arun Kumar; Kepp, Kasper Planeta

    2016-01-01

    Nearly 200 mutations in the gene coding for presenilin 1 (PSEN1) cause early-onset Alzheimer's Disease, yet the molecular mechanism remains obscure. As a meta-analysis, we compiled available clinical and biochemical data for PSEN1 variants and correlated these to chemical properties of the mutants...... protein stability. This explains why the many mutations that spread out across the protein and far from the catalytic aspartates can cause disease. The identified molecular determinants of clinical age of symptom onset may be relevant to future presenilin-modulating therapies specifically directed towards...

  16. Gain-of-function SOS1 mutations cause a distinctive form of noonansyndrome

    Energy Technology Data Exchange (ETDEWEB)

    Tartaglia, Marco; Pennacchio, Len A.; Zhao, Chen; Yadav, KamleshK.; Fodale, Valentina; Sarkozy, Anna; Pandit, Bhaswati; Oishi, Kimihiko; Martinelli, Simone; Schackwitz, Wendy; Ustaszewska, Anna; Martin, Joes; Bristow, James; Carta, Claudio; Lepri, Francesca; Neri, Cinzia; Vasta,Isabella; Gibson, Kate; Curry, Cynthia J.; Lopez Siguero, Juan Pedro; Digilio, Maria Cristina; Zampino, Giuseppe; Dallapiccola, Bruno; Bar-Sagi, Dafna; Gelb, Brude D.

    2006-09-01

    Noonan syndrome (NS) is a developmental disordercharacterized by short stature, facial dysmorphia, congenital heartdefects and skeletal anomalies1. Increased RAS-mitogenactivated proteinkinase (MAPK) signaling due to PTPN11 and KRAS mutations cause 50 percentof NS2-6. Here, we report that 22 of 129 NS patients without PTPN11 orKRAS mutation (17 percent) have missense mutations in SOS1, which encodesa RAS-specific guanine nucleotide exchange factor (GEF). SOS1 mutationscluster at residues implicated in the maintenance of SOS1 in itsautoinhibited form and ectopic expression of two NS-associated mutantsinduced enhanced RAS activation. The phenotype associated with SOS1defects is distinctive, although within NS spectrum, with a highprevalence of ectodermal abnormalities but generally normal developmentand linear growth. Our findings implicate for the first timegain-of-function mutations in a RAS GEF in inherited disease and define anew mechanism by which upregulation of the RAS pathway can profoundlychange human development.

  17. A novel heterozygous SOX2 mutation causing congenital bilateral anophthalmia, hypogonadotropic hypogonadism and growth hormone deficiency.

    Science.gov (United States)

    Macchiaroli, Annamaria; Kelberman, Daniel; Auriemma, Renata Simona; Drury, Suzanne; Islam, Lily; Giangiobbe, Sara; Ironi, Gabriele; Lench, Nicholas; Sowden, Jane C; Colao, Annamaria; Pivonello, Rosario; Cavallo, Luciano; Gasperi, Maurizio; Faienza, Maria Felicia

    2014-01-25

    Heterozygous de novo mutations in SOX2 have been reported in approximately 10-20% of patients with unilateral or bilateral anophthalmia or microphthalmia. An additional phenotype of hypopituitarism, with anterior pituitary hypoplasia and hypogonadotropic hypogonadism, has been reported in patients carrying SOX2 alterations. We report a novel heterozygous mutation in the SOX2 gene in a male affected with congenital bilateral anophthalmia, hypogonadotrophic hypogonadism and growth hormone deficiency. The mutation we describe is a cytosine deletion in position 905 (c905delC) which causes frameshift and an aberrant C-terminal domain. Our report highlights the fact that subjects affected with eye anomalies and harboring SOX2 mutations are at high risk for gonadotropin deficiency, which has important implications for their clinical management. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. De novo SHANK3 mutation causes Rett syndrome-like phenotype in a female patient.

    Science.gov (United States)

    Hara, Munetsugu; Ohba, Chihiro; Yamashita, Yushiro; Saitsu, Hirotomo; Matsumoto, Naomichi; Matsuishi, Toyojiro

    2015-07-01

    Rett syndrome (RTT) is a neurodevelopmental disorder predominantly affecting females. Females with the MECP2 mutations exhibit a broad spectrum of clinical manifestations ranging from classical Rett syndrome to asymptomatic carriers. Mutations of genes encoding cyclin-dependent kinase-like 5 (CDKL5) and forkhead box G1 (FOXG1) are also found in early onset RTT variants. Here, we present the first report of a female patient with RTT-like phenotype caused by SHANK3 (SH3 and multiple ankylin repeat domain 3) mutation, indicating that the clinical spectrum of SHANK3 mutations may extend to RTT-like phenotype in addition to (severe) developmental delay, absence of expressive speech, autistic behaviors and intellectual disability. © 2015 Wiley Periodicals, Inc.

  19. Congenital goitrous primary hypothyroidism in two German families caused by novel thyroid peroxidase (TPO) gene mutations.

    Science.gov (United States)

    Altmann, K; Hermanns, P; Mühlenberg, R; Fricke-Otto, S; Wentzell, R; Pohlenz, J

    2013-06-01

    Congenital hypothyroidism occurs with a prevalence of approximately 1:3 500. Defects in thyroid hormone synthesis which lead to goitrous hypothyroidism account for 10-15% of these cases. Several genetic defects have been characterized and mutations in the thyroid peroxidase (TPO) gene are the most common cause for dyshormonogenesis.So far, more than 80 mutations in the TPO gene have been described, resulting in a variable decrease in TPO bioactivity. Clinically TPO defects manifest with congenital primary goitrous hypothyroidism.We here present 2 children with congenital primary hypothyroidism, who were identified to have compound heterozygous TPO mutations. They both shared the same novel mutation in the TPO gene (C756R) in exon 13. One case presented with an apparently dominant inheritance of thyroid dyshormonogenesis. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

  20. Mutation in filamin A causes periventricular heterotopia, developmental regression, and West syndrome in males.

    Science.gov (United States)

    Masruha, Marcelo R; Caboclo, Luis O S F; Carrete, Henrique; Cendes, Iscia L; Rodrigues, Murilo G; Garzon, Eliana; Yacubian, Elza M T; Sakamoto, Américo C; Sheen, Volney; Harney, Megan; Neal, Jason; Hill, R Sean; Bodell, Adria; Walsh, Christopher; Vilanova, Luiz C P

    2006-01-01

    Familial periventricular heterotopia (PH) represents a disorder of neuronal migration resulting in multiple gray-matter nodules along the lateral ventricular walls. Prior studies have shown that mutations in the filamin A (FLNA) gene can cause PH through an X-linked dominant pattern. Heterozygotic female patients usually remain asymptomatic until the second or third decade of life, when they may have predominantly focal seizures, whereas hemizygotic male fetuses typically die in utero. Recent studies have also reported mutations in FLNA in male patients with PH who are cognitively normal. We describe PH in three male siblings with PH due to FLNA, severe developmental regression, and West syndrome. The study includes the three affected brothers and their parents. Video-EEG recordings and magnetic resonance image (MRI) scanning were performed on all individuals. Mutations for FLNA were detected by using polymerase chain reaction (PCR) on genomic DNA followed by single-stranded conformational polymorphism (SSCP) analysis or sequencing. Two of the siblings are monozygotic twins, and all had West syndrome with hypsarrhythmia on EEG. MRI of the brain revealed periventricular nodules of cerebral gray-matter intensity, typical for PH. Mutational analyses demonstrated a cytosine-to-thymidine missense mutation (c. C1286T), resulting in a threonine-to-methionine amino acid substitution in exon 9 of the FLNA gene. The association between PH and West syndrome, to our knowledge, has not been previously reported. Males with PH have been known to harbor FLNA mutations, although uniformly, they either show early lethality or survive and have a normal intellect. The current studies show that FLNA mutations can cause periventricular heterotopia, developmental regression, and West syndrome in male patients, suggesting that this type of FLNA mutation may contribute to severe neurologic deficits.

  1. Missense mutations in LRP5 are not a common cause of idiopathic osteoporosis in adult men.

    Science.gov (United States)

    Crabbe, Patricia; Balemans, Wendy; Willaert, Andy; van Pottelbergh, Inge; Cleiren, Erna; Coucke, Paul J; Ai, Minrong; Goemaere, Stefan; van Hul, Wim; de Paepe, Anne; Kaufman, Jean-Marc

    2005-11-01

    We studied whether the LRP5 gene contributes to the clinical phenotype of IO in men. Mutation analysis in 66 IO men revealed a range of sequence variants, of which two missense variants were shown to be of functional relevance. Mutations in the LDL receptor-related protein 5 (LRP5) gene have been associated with extreme bone phenotypes, which makes LRP5 a plausible candidate gene for idiopathic osteoporosis (IO). In 66 men with IO, all 23 exons and exon-intron boundaries of the LRP5 gene were screened for mutations, and functional analyses were performed for those that were putatively involved in the phenotype. Mutation analysis in the IO probands revealed five missense mutations, of which 1067C>T (S356L), 1364C>T (S455L), and 4609G>A (A1537T) were of potential functional significance because they were located in highly conserved regions of LRP5 and not found in a control panel. Segregation analysis in the respective families could not exclude their possible causality for IO. Furthermore, functional analyses clearly showed an inhibitory effect of mutations 1067C>T and 1364C>T on Wnt signal transduction. These effects are most likely caused by impaired LRP5 synthesis in the case of 1067C>T and failure of protein trafficking to the cell surface for 1364C>T. For 2 of 66 IO probands, a mutation in the LRP5 gene with proven functionality was found. The findings indicate that carrying an LRP5 mutation is a risk factor for IO, but that overall, IO in men is infrequently underlied by such a mutation.

  2. A novel STXBP1 mutation causes typical Rett syndrome in a Japanese girl.

    Science.gov (United States)

    Yuge, Kotaro; Iwama, Kazuhiro; Yonee, Chihiro; Matsufuji, Mayumi; Sano, Nozomi; Saikusa, Tomoko; Yae, Yukako; Yamashita, Yushiro; Mizuguchi, Takeshi; Matsumoto, Naomichi; Matsuishi, Toyojiro

    2018-03-12

    Rett syndrome (RTT) is a neurodevelopmental disorder mostly caused by mutations in Methyl-CpG-binding protein 2 (MECP2); however, mutations in various other genes may lead to RTT-like phenotypes. Here, we report the first case of a Japanese girl with RTT caused by a novel syntaxin-binding protein 1 (STXBP1) frameshift mutation (c.60delG, p.Lys21Argfs*16). She showed epilepsy at one year of age, regression of acquired psychomotor abilities thereafter, and exhibited stereotypic hand and limb movements at 3 years of age. Her epilepsy onset was earlier than is typical for RTT patients. However, she fully met the 2010 diagnostic criteria of typical RTT. STXBP1 mutations cause early infantile epileptic encephalopathy (EIEE), various intractable epilepsies, and neurodevelopmental disorders. However, the case described here presented a unique clinical presentation of typical RTT without EIEE and a novel STXBP1 mutation. Copyright © 2018 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  3. Compound heterozygous mutations in UBA5 causing early-onset epileptic encephalopathy in two sisters.

    Science.gov (United States)

    Arnadottir, Gudny A; Jensson, Brynjar O; Marelsson, Sigurdur E; Sulem, Gerald; Oddsson, Asmundur; Kristjansson, Ragnar P; Benonisdottir, Stefania; Gudjonsson, Sigurjon A; Masson, Gisli; Thorisson, Gudmundur A; Saemundsdottir, Jona; Magnusson, Olafur Th; Jonasdottir, Adalbjorg; Jonasdottir, Aslaug; Sigurdsson, Asgeir; Gudbjartsson, Daniel F; Thorsteinsdottir, Unnur; Arngrimsson, Reynir; Sulem, Patrick; Stefansson, Kari

    2017-10-02

    Epileptic encephalopathies are a group of childhood epilepsies that display high phenotypic and genetic heterogeneity. The recent, extensive use of next-generation sequencing has identified a large number of genes in epileptic encephalopathies, including UBA5 in which biallelic mutations were first described as pathogenic in 2016 (Colin E et al., Am J Hum Genet 99(3):695-703, 2016. Muona M et al., Am J Hum Genet 99(3):683-694, 2016). UBA5 encodes an activating enzyme for a post-translational modification mechanism known as ufmylation, and is the first gene from the ufmylation pathway that is linked to disease. We sequenced the genomes of two sisters with early-onset epileptic encephalopathy along with their unaffected parents in an attempt to find a genetic cause for their condition. The sisters, born in 2004 and 2006, presented with infantile spasms at six months of age, which later progressed to recurrent, treatment-resistant seizures. We detected a compound heterozygous genotype in UBA5 in the sisters, a genotype not seen elsewhere in an Icelandic reference set of 30,067 individuals nor in public databases. One of the mutations, c.684G > A, is a paternally inherited exonic splicing mutation, occuring at the last nucleotide of exon 7 of UBA5. The mutation is predicted to disrupt the splice site, resulting in loss-of-function of one allele of UBA5. The second mutation is a maternally inherited missense mutation, p.Ala371Thr, previously reported as pathogenic when in compound heterozygosity with a loss-of-function mutation in UBA5 and is believed to produce a hypomorphic allele. Supportive of this, we have identified three adult Icelanders homozygous for the p.Ala371Thr mutation who show no signs of neurological disease. We describe compound heterozygous mutations in the UBA5 gene in two sisters with early-onset epileptic encephalopathy. To our knowledge, this is the first description of mutations in UBA5 since the initial discovery that pathogenic biallelic

  4. Novel Mutations and Mutation Combinations ofTMPRSS3Cause Various Phenotypes in One Chinese Family with Autosomal Recessive Hearing Impairment.

    Science.gov (United States)

    Gao, Xue; Yuan, Yong-Yi; Wang, Guo-Jian; Xu, Jin-Cao; Su, Yu; Lin, Xi; Dai, Pu

    2017-01-01

    Autosomal recessive hearing impairment with postlingual onset is rare. Exceptions are caused by mutations in the TMPRSS3 gene, which can lead to prelingual (DFNB10) as well as postlingual deafness (DFNB8). TMPRSS3 mutations can be classified as mild or severe, and the phenotype is dependent on the combination of TMPRSS3 mutations. The combination of two severe mutations leads to profound hearing impairment with a prelingual onset, whereas severe mutations in combination with milder TMPRSS3 mutations lead to a milder phenotype with postlingual onset. We characterized a Chinese family (number FH1523) with not only prelingual but also postlingual hearing impairment. Three mutations in TMPRSS3 , one novel mutation c.36delC [p.(Phe13Serfs⁎12)], and two previously reported pathogenic mutations, c.916G>A (p.Ala306Thr) and c.316C>T (p.Arg106Cys), were identified. Compound heterozygous mutations of p.(Phe13Serfs⁎12) and p.Ala306Thr manifest as prelingual, profound hearing impairment in the patient (IV: 1), whereas the combination of p.Arg106Cys and p.Ala306Thr manifests as postlingual, milder hearing impairment in the patient (II: 2, II: 3, II: 5), suggesting that p.Arg106Cys mutation has a milder effect than p.(Phe13Serfs⁎12). We concluded that different combinations of TMPRSS3 mutations led to different hearing impairment phenotypes (DFNB8/DFNB10) in this family.

  5. Two novel mutations in the PPIB gene cause a rare pedigree of osteogenesis imperfecta type IX.

    Science.gov (United States)

    Jiang, Yu; Pan, Jingxin; Guo, Dongwei; Zhang, Wei; Xie, Jie; Fang, Zishui; Guo, Chunmiao; Fang, Qun; Jiang, Weiying; Guo, Yibin

    2017-06-01

    Osteogenesis imperfecta (OI) is a rare genetic skeletal disorder characterized by increased bone fragility and vulnerability to fractures. PPIB is identified as a candidate gene for OI-IX, here we detect two pathogenic mutations in PPIB and analyze the genotype-phenotype correlation in a Chinese family with OI. Next-generation sequencing (NGS) was used to screen the whole exome of the parents of proband. Screening of variation frequency, evolutionary conservation comparisons, pathogenicity evaluation, and protein structure prediction were conducted to assess the pathogenicity of the novel mutations. Sanger sequencing was used to confirm the candidate variants. RTQ-PCR was used to analyze the PPIB gene expression. All mutant genes screened out by NGS were excluded except PPIB. Two novel heterozygous PPIB mutations (father, c.25A>G; mother, c.509G>A) were identified in relation to osteogenesis imperfecta type IX. Both mutations were predicted to be pathogenic by bioinformatics analysis and RTQ-PCR analysis revealed downregulated PPIB expression in the two carriers. We report a rare pedigree with an autosomal recessive osteogenesis imperfecta type IX (OI-IX) caused by two novel PPIB mutations identified for the first time in China. The current study expands our knowledge of PPIB mutations and their associated phenotypes, and provides new information on the genetic defects associated with this disease for clinical diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. A de novo nonsense PDGFB mutation causing idiopathic basal ganglia calcification with laryngeal dystonia.

    Science.gov (United States)

    Nicolas, Gaël; Jacquin, Agnès; Thauvin-Robinet, Christel; Rovelet-Lecrux, Anne; Rouaud, Olivier; Pottier, Cyril; Aubriot-Lorton, Marie-Hélène; Rousseau, Stéphane; Wallon, David; Duvillard, Christian; Béjot, Yannick; Frébourg, Thierry; Giroud, Maurice; Campion, Dominique; Hannequin, Didier

    2014-10-01

    Idiopathic basal ganglia calcification (IBGC) is characterized by brain calcification and a wide variety of neurologic and psychiatric symptoms. In families with autosomal dominant inheritance, three causative genes have been identified: SLC20A2, PDGFRB, and, very recently, PDGFB. Whereas in clinical practice sporadic presentation of IBGC is frequent, well-documented reports of true sporadic occurrence are rare. We report the case of a 20-year-old woman who presented laryngeal dystonia revealing IBGC. Her healthy parents' CT scans were both normal. We identified in the proband a new nonsense mutation in exon 4 of PDGFB, c.439C>T (p.Gln147*), which was absent from the parents' DNA. This mutation may result in a loss-of-function of PDGF-B, which has been shown to cause IBGC in humans and to disrupt the blood-brain barrier in mice, resulting in brain calcification. The c.439C>T mutation is located between two previously reported nonsense mutations, c.433C>T (p.Gln145*) and c.445C>T (p.Arg149*), on a region that could be a hot spot for de novo mutations. We present the first full demonstration of the de novo occurrence of an IBGC-causative mutation in a sporadic case.

  7. EPILEPSY CAUSED BY PCDH19 GENE MUTATION: A REVIEW OF LITERATURE AND THE AUTHORS’ OBSERVATIONS

    Directory of Open Access Journals (Sweden)

    K. Yu. Mukhin

    2016-01-01

    Full Text Available Mutation in the PCDH19 gene was first described by L.M. Dibbens et al. in 2008. Mutations in this gene are associated with epilepsy and mental retardation limited to females. The clinical manifestations that are observed in some patients with PCDH19 mutation and Dravet syndrome that is caused by mutation in the SCN1A gene include the onset of febrile and afebrile seizures in infancy, serial seizures during fever, and regression in development after the onset of seizures. Due to the fact that the two diseases have common clinical signs, it is best to test for PCDH19 mutation in patients with the clinical picture of Dravet syndrome and a negative test for SCN1A. In general, the number of scientific papers devoted to analysis and recommendations for the choice of therapy in patients with rare genetic pathology is small now. We analyzed the specific features of clinical signs and therapy in our two observed female patients aged 4 and 11 years with verified PCDH19 mutation. Both patients were noted to have severe epilepsy with febrile convulsions with the development of status epilepticus and to be unresponsive to antiepileptic therapy. The use of different antiepileptic drugs (valproate, oxcarbazepine, phenobarbital, topiramate, levetiracetam at different combinations failed to control the course of epilepsy in the 4-year-old patient whereas the 11-year-old patient who took a combination of valproic acid and benzodiazepines achieved a positive effect.

  8. Autosomal recessive mutations in THOC6 cause intellectual disability: syndrome delineation requiring forward and reverse phenotyping.

    Science.gov (United States)

    Amos, J S; Huang, L; Thevenon, J; Kariminedjad, A; Beaulieu, C L; Masurel-Paulet, A; Najmabadi, H; Fattahi, Z; Beheshtian, M; Tonekaboni, S H; Tang, S; Helbig, K L; Alcaraz, W; Rivière, J-B; Faivre, L; Innes, A M; Lebel, R R; Boycott, K M

    2017-01-01

    THOC6 is a part of the THO complex, which is involved in coordinating mRNA processing with export. The THO complex interacts with additional components to form the larger TREX complex (transcription export complex). Previously, a homozygous missense mutation in THOC6 in the Hutterite population was reported in association with syndromic intellectual disability. Using exome sequencing, we identified three unrelated patients with bi-allelic mutations in THOC6 associated with intellectual disability and additional clinical features. Two of the patients were compound heterozygous for a stop and a missense mutation, and the third was homozygous for a missense mutation; the missense mutations were predicted to be pathogenic by in silico analysis and modeling. Clinical features of the three newly identified patients and those previously reported are reviewed; intellectual disability is moderate to severe, and malformations are variable including renal and heart defects, cleft palate, microcephaly, and corpus callosum dysgenesis. Facial features are variable and include tall forehead, short upslanting palpebral fissures +/- deep set eyes, and a long nose with overhanging columella. These subtle facial features render the diagnosis difficult to make in isolation with certainty. Our results expand the mutational and clinical spectrum of this rare disease, confirm that THOC6 is an intellectual disability causing gene, while providing insight into the importance of the THO complex in neurodevelopment. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Mutations in the DNA methyltransferase gene, DNMT3A, cause an overgrowth syndrome with intellectual disability

    Science.gov (United States)

    Tatton-Brown, Katrina; Seal, Sheila; Ruark, Elise; Harmer, Jenny; Ramsay, Emma; del Vecchio Duarte, Silvana; Zachariou, Anna; Hanks, Sandra; O’Brien, Eleanor; Aksglaede, Lise; Baralle, Diana; Dabir, Tabib; Gener, Blanca; Goudie, David; Homfray, Tessa; Kumar, Ajith; Pilz, Daniela T; Selicorni, Angelo; Temple, I Karen; Van Maldergem, Lionel; Yachelevich, Naomi; van Montfort, Robert; Rahman, Nazneen

    2014-01-01

    Overgrowth disorders are a heterogeneous group of conditions characterised by increased growth parameters and variable other clinical features, such as intellectual disability and facial dysmorphism1. To identify novel causes of human overgrowth we performed exome sequencing in 10 proband-parent trios and detected two de novo DNMT3A mutations. We identified 11 additional de novo mutations through DNMT3A sequencing of a further 142 individuals with overgrowth. The mutations were all located in functional DNMT3A domains and protein modelling suggests they interfere with domain-domain interactions and histone binding. No similar mutations were present in 1000 UK population controls (13/152 vs 0/1000; P<0.0001). Mutation carriers had a distinctive facial appearance, intellectual disability and increased height. DNMT3A encodes a key methyltransferase essential for establishing the methylation imprint in embryogenesis and is commonly somatically mutated in acute myeloid leukaemia2-4. Thus DNMT3A joins an emerging group of epigenetic DNA and histone modifying genes associated with both developmental growth disorders and haematological malignancies5. PMID:24614070

  10. Novel CACNA1S mutation causes autosomal dominant hypokalemic periodic paralysis in a South American family.

    Science.gov (United States)

    Ke, Tie; Gomez, Cladelis Rubio; Mateus, Heidi Eliana; Castano, Juan Andres; Wang, Qing Kenneth

    2009-11-01

    Hypokalaemic periodic paralysis (HypoPP) is an autosomal dominant disorder, which is characterized by periodic attacks of muscle weakness associated with a decrease in the serum potassium level. A major disease-causing gene for HypoPP has been identified as CACNA1S, which encodes the skeletal muscle calcium channel alpha-subunit with four transmembrane domains (I-IV), each with six transmembrane segments (S1-S6). To date, all CACNA1S mutations identified in HypoPP patients are located within the voltage-sensor S4 segment. In this study we report a novel CACNA1S mutation in a new region of the protein, the S3 segment of domain III. We characterized a four-generation South American family with HypoPP. Genetic analysis identified a novel V876E mutation in all HypoPP patients in the family, but not in normal family members or 160 control people. Clinical analysis indicates that mutation V876E is associated with a severe outcome as characterized by a very early age of onset, complete penetrance and a severe prognosis including death. These results identify a new mutation in CACNA1S and expand the spectrum of CACNA1S mutations associated with HypoPP.

  11. Functional Cathepsin C mutations cause different Papillon-Lefèvre syndrome phenotypes.

    Science.gov (United States)

    Noack, Barbara; Görgens, Heike; Schacher, Beate; Puklo, Magda; Eickholz, Peter; Hoffmann, Thomas; Schackert, Hans Konrad

    2008-04-01

    The autosomal-recessive Papillon-Lefèvre syndrome (PLS) is characterized by severe aggressive periodontitis, combined with palmoplantar hyperkeratosis, and is caused by mutations in the Cathepsin C (CTSC) gene. This study aimed to identify CTSC mutations in different PLS phenotypes, including atypical forms and isolated pre-pubertal aggressive periodontitis (PAP). Thirteen families with different phenotypes were analysed by direct sequencing of the entire coding region and the regulatory regions of CTSC. The function of novel mutations was tested with enzyme activity measurements. In 11 of 13 families, 12 different pathogenic CTSC mutations were found in 10 typical PLS patients, three atypical cases and one PAP patient. Out of four novel mutations, three result in protein truncation and are thus considered to be pathogenic. The homozygous c.854C>T nucleotide exchange (p.P285L) was associated with an almost complete loss of enzyme activity. The observed phenotypic heterogeneity could not be associated with specific genotypes. The phenotypic variability of the PLS associated with an identical genetic background may reflect the influence of additional genetic or environmental factors on disease characteristics. CTSC mutation analyses should be considered for differential diagnosis in all children suffering from severe aggressive periodontitis.

  12. Inherited Cardiac Diseases Caused by Mutations in the Nav1.5 Sodium Channel

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Jacob; Winkel, Bo Gregers; Grunnet, Morten

    2009-01-01

    Cardiac Diseases Caused by SCN5A Mutations. A prerequisite for a normal cardiac function is a proper generation and propagation of electrical impulses. Contraction of the heart is obtained through a delicate matched transmission of the electrical impulses. A pivotal element of the impulse...

  13. DNA methyltransferase 3B mutations linked to the ICF syndrome cause dysregulation of lymphogenesis genes.

    NARCIS (Netherlands)

    Ehrlich, M.; Buchanan, K.L.; Tsien, F.; Jiang, G.; Sun, B.; Uicker, W.; Weemaes, C.M.R.; Smeets, D.F.C.M.; Sperling, K.; Belohradsky, B.H.; Tommerup, N.; Misek, D.E.; Rouillard, J.M.; Kuick, R.; Hanash, S.M.

    2001-01-01

    ICF (immunodeficiency, centromeric region instability and facial anomalies) is a recessive disease caused by mutations in the DNA methyltransferase 3B gene (DNMT3B). Patients have immunodeficiency, chromosome 1 (Chr1) and Chr16 pericentromeric anomalies in mitogen-stimulated lymphocytes, a small

  14. DCDC2 mutations cause a renal-hepatic ciliopathy by disrupting Wnt signaling

    NARCIS (Netherlands)

    Schueler, Markus; Braun, Daniela A; Chandrasekar, Gayathri; Gee, Heon Yung; Klasson, Timothy D.; Halbritter, Jan; Bieder, Andrea; Porath, Jonathan D; Airik, Rannar; Zhou, Weibin; LoTurco, Joseph J; Che, Alicia; Otto, Edgar A; Böckenhauer, Detlef; Sebire, Neil J; Honzik, Tomas; Harris, Peter C; Koon, Sarah J; Gunay-Aygun, Meral; Saunier, Sophie; Zerres, Klaus; Bruechle, Nadina Ortiz; Drenth, Joost P H; Pelletier, Laurence; Tapia-Páez, Isabel; Lifton, Richard P; Giles, R; Kere, Juha; Hildebrandt, Friedhelm

    2015-01-01

    Nephronophthisis-related ciliopathies (NPHP-RC) are recessive diseases characterized by renal dysplasia or degeneration. We here identify mutations of DCDC2 as causing a renal-hepatic ciliopathy. DCDC2 localizes to the ciliary axoneme and to mitotic spindle fibers in a cell-cycle-dependent manner.

  15. MRPL44 mutations cause a slowly progressive multisystem disease with childhood-onset hypertrophic cardiomyopathy

    NARCIS (Netherlands)

    Distelmaier, F.; Haack, T.B.; Catarino, C.B.; Gallenmuller, C.; Rodenburg, R.J.T.; Strom, T.M.; Baertling, F.; Meitinger, T.; Mayatepek, E.; Prokisch, H.; Klopstock, T.

    2015-01-01

    Defects in mitochondrial translation may lead to combined respiratory chain deficiency and typically cause childhood-onset multisystem disease. Only recently, a homozygous missense mutation (c.467T > G, p.Leu156Arg) in MRPL44, encoding a protein of the large subunit of the mitochondrial ribosome,

  16. Audiometric Characteristics of a Dutch Family with a New Mutation in GATA3 Causing HDR Syndrome.

    NARCIS (Netherlands)

    Beelen, E. van; Leijendeckers, J.M.; Admiraal, R.J.C.; Huygen, P.L.M.; Hoefsloot, L.H.; Pennings, R.J.E.; Snik, A.F.M.; Kunst, H.P.M.

    2014-01-01

    We present the case of a Dutch family with a new mutation (c523_528dup) in GATA3 causing HDR syndrome. HDR syndrome is characterised by hypoparathyroidism, deafness and renal defects. In this study, we describe the audiometric characteristics of 5 patients from this family. Their hearing impairment

  17. Germline mutations in WTX cause a sclerosing skeletal dysplasia but do not predispose to tumorigenesis

    NARCIS (Netherlands)

    Jenkins, Zandra A.; van Kogelenberg, Margriet; Morgan, Tim; Jeffs, Aaron; Fukuzawa, Ryuji; Pearl, Esther; Thaller, Christina; Hing, Anne V.; Porteous, Mary E.; Garcia-Miñaur, Sixto; Bohring, Axel; Lacombe, Didier; Stewart, Fiona; Fiskerstrand, Torunn; Bindoff, Laurence; Berland, Siren; Adès, Lesley C.; Tchan, Michel; David, Albert; Wilson, Louise C.; Hennekam, Raoul C. M.; Donnai, Dian; Mansour, Sahar; Cormier-Daire, Valérie; Robertson, Stephen P.

    2009-01-01

    Abnormalities in WNT signaling are implicated in a broad range of developmental anomalies and also in tumorigenesis. Here we demonstrate that germline mutations in WTX (FAM123B), a gene that encodes a repressor of canonical WNT signaling, cause an X-linked sclerosing bone dysplasia, osteopathia

  18. Frontotemporal dementia caused by CHMP2B mutation is characterised by neuronal lysosomal storage pathology

    DEFF Research Database (Denmark)

    Clayton, Emma L.; Mizielinska, Sarah; Edgar, James R.

    2015-01-01

    Mutations in the charged multivesicular body protein 2B (CHMP2B) cause frontotemporal dementia (FTD). We report that mice which express FTD-causative mutant CHMP2B at physiological levels develop a novel lysosomal storage pathology characterised by large neuronal autofluorescent aggregates. The a...

  19. Identification of an unusual variant peroxisome biogenesis disorder caused by mutations in the PEX16 gene

    NARCIS (Netherlands)

    Ebberink, M.S.; Csanyi, B.; Chong, W.K.; Denis, S.; Sharp, P.; Mooijer, P.A.W.; Dekker, C.J.M.; Spooner, C.; Ngu, L.H.; de Sousa, C.; Wanders, R.J.A.; Fietz, M.J.; Clayton, P.T.; Waterham, H.R.; Ferdinandusse, S.

    2010-01-01

    Background Zellweger syndrome spectrum disorders are caused by mutations in any of at least 12 different PEX genes. This includes PEX16, which encodes an integral peroxisomal membrane protein involved in peroxisomal membrane assembly. PEX16-defective patients have been reported to have a severe

  20. Recurrent spontaneous pneumothoraces and bullous emphysema. A novel mutation causing Birt-Hogg-Dube syndrome.

    Science.gov (United States)

    Burkett, Andrew; Coffey, Niamh; Tomiak, Eva; Voduc, Nha

    2016-01-01

    Birt-Hogg-Dube syndrome (BHDS) is a rare form of classically cystic lung disease that may present with spontaneous pneumothorax. The associated skin manifestations (fibrofolliculomas) are not always present. This article describes a case of spontaneous pneumothorax secondary to bullous emphysema in an otherwise healthy gentleman caused by a novel mutation in the folliculin (FLCN) gene.

  1. Features of 5'-splice-site efficiency derived from disease-causing mutations and comparative genomics

    DEFF Research Database (Denmark)

    Roca, Xavier; Olson, Andrew J; Rao, Atmakuri R

    2008-01-01

    Many human diseases, including Fanconi anemia, hemophilia B, neurofibromatosis, and phenylketonuria, can be caused by 5'-splice-site (5'ss) mutations that are not predicted to disrupt splicing, according to position weight matrices. By using comparative genomics, we identify pairwise dependencies...

  2. De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome

    NARCIS (Netherlands)

    Riviere, Jean-Baptiste; van Bon, Bregje W. M.; Hoischen, Alexander; Kholmanskikh, Stanislav S.; O'Roak, Brian J.; Gilissen, Christian; Gijsen, Sabine; Sullivan, Christopher T.; Christian, Susan L.; Abdul-Rahman, Omar A.; Atkin, Joan F.; Chassaing, Nicolas; Drouin-Garraud, Valerie; Fry, Andrew E.; Fryns, Jean-Pierre; Gripp, Karen W.; Kempers, Marlies; Kleefstra, Tjitske; Mancini, Grazia M. S.; Nowaczyk, Malgorzata J. M.; van Ravenswaaij-Arts, Conny M. A.; Roscioli, Tony; Marble, Michael; Rosenfeld, Jill A.; Siu, Victoria M.; de Vries, Bert B. A.; Shendure, Jay; Verloes, Alain; Veltman, Joris A.; Brunner, Han G.; Ross, M. Elizabeth; Pilz, Daniela T.; Dobyns, William B.

    Brain malformations are individually rare but collectively common causes of developmental disabilities(1-3). Many forms of malformation occur sporadically and are associated with reduced reproductive fitness, pointing to a causative role for de novo mutations(4,5). Here, we report a study of

  3. Protein-truncating mutations in ASPM cause variable reduction in brain size

    NARCIS (Netherlands)

    Bond, Jacquelyn; Scott, Sheila; Hampshire, Daniel J.; Springell, Kelly; Corry, Peter; Abramowicz, Marc J.; Mochida, Ganesh H.; Hennekam, Raoul C. M.; Maher, Eamonn R.; Fryns, Jean-Pierre; Alswaid, Abdulrahman; Jafri, Hussain; Rashid, Yasmin; Mubaidin, Ammar; Walsh, Christopher A.; Roberts, Emma; Woods, C. Geoffrey

    2003-01-01

    Mutations in the ASPM gene at the MCPH5 locus are expected to be the most common cause of human autosomal recessive primary microcephaly (MCPH), a condition in which there is a failure of normal fetal brain development, resulting in congenital microcephaly and mental retardation. We have performed

  4. Mutations in KRT5 and KRT14 cause epidermolysis bullosa simplex in 75% of the patients

    NARCIS (Netherlands)

    Bolling, M. C.; Lemmink, H. H.; Jansen, G. H. L.; Jonkman, M. F.

    P>Background Epidermolysis bullosa simplex (EBS) is a mechanobullous genodermatosis that may be caused by mutations in the genes KRT5 and KRT14 encoding the basal epidermal keratins 5 (K5) and 14 (K14). Three main clinical subtypes of EBS exist, differing in onset, distribution and severity of skin

  5. Absent Thalami Caused by a Homozygous EARS2 Mutation: Expanding Disease Spectrum of LTBL

    NARCIS (Netherlands)

    Kevelam, Sietske H.; Klouwer, Femke C. C.; Fock, Johanna M.; Salomons, Gajja S.; Bugiani, Marianna; van der Knaap, Marjo S.

    2016-01-01

    Leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) is caused by autosomal recessive EARS2 mutations. Onset is most often in infancy, but in severe cases in the neonatal period. Patients typically have magnetic resonance imaging (MRI) signal abnormalities involving

  6. Absent Thalami Caused by a Homozygous EARS2 Mutation : Expanding Disease Spectrum of LTBL

    NARCIS (Netherlands)

    Kevelam, Sietske H.; Klouwer, Femke C. C.; Fock, Johanna M.; Salomons, Gajja S.; Bugiani, Marianna; van der Knaap, Marjo S.

    Leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) is caused by autosomal recessive EARS2 mutations. Onset is most often in infancy, but in severe cases in the neonatal period. Patients typically have magnetic resonance imaging (MRI) signal abnormalities involving

  7. Establishing the precise evolutionary history of a gene improves prediction of disease-causing missense mutations.

    Science.gov (United States)

    Adebali, Ogun; Reznik, Alexander O; Ory, Daniel S; Zhulin, Igor B

    2016-10-01

    Predicting the phenotypic effects of mutations has become an important application in clinical genetic diagnostics. Computational tools evaluate the behavior of the variant over evolutionary time and assume that variations seen during the course of evolution are probably benign in humans. However, current tools do not take into account orthologous/paralogous relationships. Paralogs have dramatically different roles in Mendelian diseases. For example, whereas inactivating mutations in the NPC1 gene cause the neurodegenerative disorder Niemann-Pick C, inactivating mutations in its paralog NPC1L1 are not disease-causing and, moreover, are implicated in protection from coronary heart disease. We identified major events in NPC1 evolution and revealed and compared orthologs and paralogs of the human NPC1 gene through phylogenetic and protein sequence analyses. We predicted whether an amino acid substitution affects protein function by reducing the organism's fitness. Removing the paralogs and distant homologs improved the overall performance of categorizing disease-causing and benign amino acid substitutions. The results show that a thorough evolutionary analysis followed by identification of orthologs improves the accuracy in predicting disease-causing missense mutations. We anticipate that this approach will be used as a reference in the interpretation of variants in other genetic diseases as well.Genet Med 18 10, 1029-1036.

  8. Recessive mutations in PTHR1 cause contrasting skeletal dysplasias in Eiken and Blomstrand syndromes

    DEFF Research Database (Denmark)

    Duchatelet, Sabine; Ostergaard, Elsebet; Cortes, Dina

    2005-01-01

    Eiken syndrome is a rare autosomal recessive skeletal dysplasia. We identified a truncation mutation in the C-terminal cytoplasmic tail of the parathyroid hormone (PTH)/PTH-related peptide (PTHrP) type 1 receptor (PTHR1) gene as the cause of this syndrome. Eiken syndrome differs from Jansen...

  9. Wolfram gene (WFS1) mutation causes autosomal dominant congenital nuclear cataract in humans.

    Science.gov (United States)

    Berry, Vanita; Gregory-Evans, Cheryl; Emmett, Warren; Waseem, Naushin; Raby, Jacob; Prescott, DeQuincy; Moore, Anthony T; Bhattacharya, Shomi S

    2013-12-01

    Congenital cataracts are an important cause of bilateral visual impairment in infants. Through genome-wide linkage analysis in a four-generation family of Irish descent, the disease-associated gene causing autosomal-dominant congenital nuclear cataract was mapped to chromosome 4p16.1. The maximum logarithm of odds (LOD) score was 2.62 at a recombination fraction θ=0, obtained for marker D4S432 physically close to the Wolfram gene (WFS1). By sequencing the coding regions and intron-exon boundaries of WFS1, we identified a DNA substitution (c.1385A-to-G) in exon 8, causing a missense mutation at codon 462 (E462G) of the Wolframin protein. This is the first report of a mutation in this gene causing an isolated nuclear congenital cataract. These findings suggest that the membrane trafficking protein Wolframin may be important for supporting the developing lens.

  10. A novel NHS mutation causes Nance-Horan Syndrome in a Chinese family.

    Science.gov (United States)

    Tian, Qi; Li, Yunping; Kousar, Rizwana; Guo, Hui; Peng, Fenglan; Zheng, Yu; Yang, Xiaohua; Long, Zhigao; Tian, Runyi; Xia, Kun; Lin, Haiying; Pan, Qian

    2017-01-07

    Nance-Horan Syndrome (NHS) (OMIM: 302350) is a rare X-linked developmental disorder characterized by bilateral congenital cataracts, with occasional dental anomalies, characteristic dysmorphic features, brachymetacarpia and mental retardation. Carrier females exhibit similar manifestations that are less severe than in affected males. Here, we report a four-generation Chinese family with multiple affected individuals presenting Nance-Horan Syndrome. Whole-exome sequencing combined with RT-PCR and Sanger sequencing was used to search for a genetic cause underlying the disease phenotype. Whole-exome sequencing identified in all affected individuals of the family a novel donor splicing site mutation (NM_198270: c.1045 + 2T > A) in intron 4 of the gene NHS, which maps to chromosome Xp22.13. The identified mutation results in an RNA processing defect causing a 416-nucleotide addition to exon 4 of the mRNA transcript, likely producing a truncated NHS protein. The donor splicing site mutation NM_198270: c.1045 + 2T > A of the NHS gene is the causative mutation in this Nance-Horan Syndrome family. This research broadens the spectrum of NHS gene mutations, contributing to our understanding of the molecular genetics of NHS.

  11. Mutations in plasmalemma vesicle-associated protein cause severe syndromic protein-losing enteropathy.

    Science.gov (United States)

    Broekaert, Ilse Julia; Becker, Kerstin; Gottschalk, Ingo; Körber, Friederike; Dötsch, Jörg; Thiele, Holger; Altmüller, Janine; Nürnberg, Peter; Hünseler, Christoph; Cirak, Sebahattin

    2018-04-16

    Protein-losing enteropathy (PLE) is characterised by gastrointestinal protein leakage due to loss of mucosal integrity or lymphatic abnormalities. PLE can manifest as congenital diarrhoea and should be differentiated from other congenital diarrhoeal disorders. Primary PLEs are genetically heterogeneous and the underlying genetic defects are currently emerging. We report an infant with fatal PLE for whom we aimed to uncover the underlying pathogenic mutation. We performed whole exome sequencing (WES) for the index patient. Variants were classified based on the American College of Medical Genetics and Genomics guidelines. WES results and our detailed clinical description of the patient were compared with the literature. We discovered a novel homozygous stop mutation (c.988C>T, p.Q330*) in the Plasmalemma Vesicle-Associated Protein ( PLVAP ) gene in a newborn with fatal PLE, facial dysmorphism, and renal, ocular and cardiac anomalies. The Q330* mutation is predicted to result in complete loss of PLVAP protein expression leading to deletion of the diaphragms of endothelial fenestrae, resulting in plasma protein extravasation and PLE. Recently, another single homozygous stop mutation in PLVAP causing lethal PLE in an infant was reported. Our findings validate PLVAP mutations as a cause of syndromic PLE. Prenatal anomalies, severe PLE and syndromic features may guide the diagnosis of this rare disease. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. Exome sequencing identifies MAX mutations as a cause of hereditary pheochromocytoma.

    Science.gov (United States)

    Comino-Méndez, Iñaki; Gracia-Aznárez, Francisco J; Schiavi, Francesca; Landa, Iñigo; Leandro-García, Luis J; Letón, Rocío; Honrado, Emiliano; Ramos-Medina, Rocío; Caronia, Daniela; Pita, Guillermo; Gómez-Graña, Alvaro; de Cubas, Aguirre A; Inglada-Pérez, Lucía; Maliszewska, Agnieszka; Taschin, Elisa; Bobisse, Sara; Pica, Giuseppe; Loli, Paola; Hernández-Lavado, Rafael; Díaz, José A; Gómez-Morales, Mercedes; González-Neira, Anna; Roncador, Giovanna; Rodríguez-Antona, Cristina; Benítez, Javier; Mannelli, Massimo; Opocher, Giuseppe; Robledo, Mercedes; Cascón, Alberto

    2011-06-19

    Hereditary pheochromocytoma (PCC) is often caused by germline mutations in one of nine susceptibility genes described to date, but there are familial cases without mutations in these known genes. We sequenced the exomes of three unrelated individuals with hereditary PCC (cases) and identified mutations in MAX, the MYC associated factor X gene. Absence of MAX protein in the tumors and loss of heterozygosity caused by uniparental disomy supported the involvement of MAX alterations in the disease. A follow-up study of a selected series of 59 cases with PCC identified five additional MAX mutations and suggested an association with malignant outcome and preferential paternal transmission of MAX mutations. The involvement of the MYC-MAX-MXD1 network in the development and progression of neural crest cell tumors is further supported by the lack of functional MAX in rat PCC (PC12) cells and by the amplification of MYCN in neuroblastoma and suggests that loss of MAX function is correlated with metastatic potential.

  13. Novel COL4A1 mutations cause cerebral small vessel disease by haploinsufficiency.

    Science.gov (United States)

    Lemmens, Robin; Maugeri, Alessandra; Niessen, Hans W M; Goris, An; Tousseyn, Thomas; Demaerel, Philippe; Corveleyn, Anniek; Robberecht, Wim; van der Knaap, Marjo S; Thijs, Vincent N; Zwijnenburg, Petra J G

    2013-01-15

    Mutations in COL4A1 have been identified in families with hereditary small vessel disease of the brain presumably due to a dominant-negative mechanism. Here, we report on two novel mutations in COL4A1 in two families with porencephaly, intracerebral hemorrhage and severe white matter disease caused by haploinsufficiency. Two families with various clinical presentations of cerebral microangiopathy and autosomal dominant inheritance were examined. Clinical, neuroradiological and genetic investigations were performed. Electron microscopy of the skin was also performed. In one of the families, sequence analysis revealed a one base deletion, c.2085del, leading to a frameshift and a premature stopcodon, p.(Gly696fs). In the other family, a splice site mutation was identified, c.2194-1G>A, which most likely leads to skipping of an exon with a frameshift and premature termination as a result. In fibroblasts of affected individuals from both the families, nonsense-mediated decay (NMD) of the mutant COL4A1 messenger RNAs (mRNAs) and a clear reduction of COL4A1 protein expression were demonstrated, indicating haploinsufficiency of COL4A1. Moreover, thickening of the capillary basement membrane in the skin was documented, similar to reports in patients with COL4A1 missense mutations. These findings suggest haploinsufficiency, a different mechanism from the commonly assumed dominant-negative effect, for COL4A1 mutations as a cause of (antenatal) intracerebral hemorrhage and white matter disease.

  14. Mutations in C5ORF42 cause Joubert syndrome in the French Canadian population.

    Science.gov (United States)

    Srour, Myriam; Schwartzentruber, Jeremy; Hamdan, Fadi F; Ospina, Luis H; Patry, Lysanne; Labuda, Damian; Massicotte, Christine; Dobrzeniecka, Sylvia; Capo-Chichi, José-Mario; Papillon-Cavanagh, Simon; Samuels, Mark E; Boycott, Kym M; Shevell, Michael I; Laframboise, Rachel; Désilets, Valérie; Maranda, Bruno; Rouleau, Guy A; Majewski, Jacek; Michaud, Jacques L

    2012-04-06

    Joubert syndrome (JBTS) is an autosomal-recessive disorder characterized by a distinctive mid-hindbrain malformation, developmental delay with hypotonia, ocular-motor apraxia, and breathing abnormalities. Although JBTS was first described more than 40 years ago in French Canadian siblings, the causal mutations have not yet been identified in this family nor in most French Canadian individuals subsequently described. We ascertained a cluster of 16 JBTS-affected individuals from 11 families living in the Lower St. Lawrence region. SNP genotyping excluded the presence of a common homozygous mutation that would explain the clustering of these individuals. Exome sequencing performed on 15 subjects showed that nine affected individuals from seven families (including the original JBTS family) carried rare compound-heterozygous mutations in C5ORF42. Two missense variants (c.4006C>T [p.Arg1336Trp] and c.4690G>A [p.Ala1564Thr]) and a splicing mutation (c.7400+1G>A), which causes exon skipping, were found in multiple subjects that were not known to be related, whereas three other truncating mutations (c.6407del [p.Pro2136Hisfs*31], c.4804C>T [p.Arg1602*], and c.7477C>T [p.Arg2493*]) were identified in single individuals. None of the unaffected first-degree relatives were compound heterozygous for these mutations. Moreover, none of the six putative mutations were detected among 477 French Canadian controls. Our data suggest that mutations in C5ORF42 explain a large portion of French Canadian individuals with JBTS. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  15. Functional Study of Ectodysplasin-A Mutations Causing Non-Syndromic Tooth Agenesis

    Science.gov (United States)

    Liu, Yang; Liu, Haochen; Zhao, Hongshan; Zhang, Guozhong; Snead, Malcolm L.; Han, Dong; Feng, Hailan

    2016-01-01

    Recent studies have demonstrated that ectodysplasin-A (EDA) mutations are associated with non-syndromic tooth agenesis. Indeed, we were the first to report three novel EDA mutations (A259E, R289C and R334H) in sporadic non-syndromic tooth agenesis. We studied the mechanism linking EDA mutations and non-syndromic tooth agenesis in human embryonic kidney 293T cells and mouse ameloblast-derived LS8 cells transfected with mutant isoforms of EDA. The receptor binding capability of the mutant EDA1 protein was impaired in comparison to wild-type EDA1. Although the non-syndromic tooth agenesis-causing EDA1 mutants possessed residual binding capability, the transcriptional activation of the receptor’s downstream target, nuclear factor κB (NF-κB), was compromised. We also analyzed the changes of selected genes in other signaling pathways, such as WNT and BMP, after EDA mutation. We found that non-syndromic tooth agenesis-causing EDA1 mutant proteins upregulate BMP4 (bone morphogenetic protein 4) mRNA expression and downregulate WNT10A and WNT10B (wingless-type MMTV integration site family member 10A and 10B) mRNA expression. Our results indicated that non-syndromic tooth agenesis causing EDA mutations (A259E, R289C and R334H) were loss-of-function, and suggested that EDA may regulate the expression of WNT10A, WNT10B and BMP4 via NF-κB during tooth development. The results from our study may help to understand the molecular mechanism linking specific EDA mutations with non-syndromic tooth agenesis. PMID:27144394

  16. Exome Sequencing Reveals Mutations in AIRE as a Cause of Isolated Hypoparathyroidism.

    Science.gov (United States)

    Li, Dong; Streeten, Elizabeth A; Chan, Alice; Lwin, Wint; Tian, Lifeng; Pellegrino da Silva, Renata; Kim, Cecilia E; Anderson, Mark S; Hakonarson, Hakon; Levine, Michael A

    2017-05-01

    Most cases of autosomal recessive hypoparathyroidism (HYPO) are caused by loss-of-function mutations in GCM2 or PTH. The objective of this study was to identify the underlying genetic basis for isolated HYPO in a kindred in which 3 of 10 siblings were affected. We studied the parents and the three adult affected subjects, each of whom was diagnosed with HYPO in the first decade of life. We collected clinical and biochemical data and performed whole exome sequencing analysis on DNA from the three affected subjects after negative genetic testing for known causes of HYPO. Whole exome sequencing followed by Sanger sequencing revealed that all three affected subjects were compound heterozygous for two previously reported mutations, c.967_979delCTGTCCCCTCCGC:p.(L323SfsX51) and c.995+(3_5)delGAGinsTAT, in AIRE, which encodes the autoimmune regulator protein that is defective in autoimmune polyglandular syndrome type 1 (APS-1). Each parent carries one mutation, and all of the children of the patients are either heterozygous for one mutation or wild type. The affected sister developed premature ovarian failure, but the two affected brothers have no other features of APS-1 despite elevated serum levels of anti-interferon-α antibodies. Our findings indicate that biallelic mutations in AIRE can cause isolated HYPO as well as syndromic APS-1. The presence of antibodies to interferon-α provides a highly sensitive indicator for loss of AIRE function and represents a useful marker for isolated HYPO due to AIRE mutations. Copyright © 2017 Endocrine Society

  17. Disease-causing mutations in exon 11 of the medium-chain acyl-CoA dehydrogenase gene

    DEFF Research Database (Denmark)

    Andresen, B S; Jensen, T G; Bross, P

    1994-01-01

    Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most commonly recognized defect of the mitochondrial beta-oxidation in humans. It is a potentially fatal, autosomal recessive inherited defect. Most patients with MCAD deficiency are homozygous for a single disease-causing mutation (G985......), causing a change from lysine to glutamate at position 304 (K304E) in the mature MCAD. Only seven non-G985 mutations, all of which are rare, have been reported. Because the G985 mutation and three of the non-G985 mutations are located in exon 11, it has been suggested that this exon may be a mutational hot...

  18. Mutations in POGLUT1, Encoding Protein O-Glucosyltransferase 1, Cause Autosomal-Dominant Dowling-Degos Disease

    OpenAIRE

    Basmanav, F. Buket; Oprisoreanu, Ana-Maria; Pasternack, Sandra M.; Thiele, Holger; Fritz, Günter; Wenzel, Jörg; Größer, Leopold; Wehner, Maria; Wolf, Sabrina; Fagerberg, Christina; Bygum, Anette; Altmüller, Janine; Rütten, Arno; Parmentier, Laurent; El Shabrawi-Caelen, Laila

    2014-01-01

    Dowling-Degos disease (DDD) is an autosomal-dominant genodermatosis characterized by progressive and disfiguring reticulate hyperpigmentation. We previously identified loss-of-function mutations in KRT5 but were only able to detect pathogenic mutations in fewer than half of our subjects. To identify additional causes of DDD, we performed exome sequencing in five unrelated affected individuals without mutations in KRT5. Data analysis identified three heterozygous mutations from these individua...

  19. Neonatal Marfan syndrome caused by an exon 25 mutation of the fibrillin-1 gene.

    Science.gov (United States)

    Elçioglu, N H; Akalin, F; Elçioglu, M; Comeglio, P; Child, A H

    2004-01-01

    Neonatal Marfan syndrome caused by an exon 25 mutation of the Fibrillin-1 gene: We describe a male infant with severe arachnodactyly, hypermobility of the fingers, flexion contractures of elbows, wrists, hips, and knees, microretrognathia, crumpled ears, rockerbottom feet, loose redundant skin, and lens dislocations. Cardiac valve insufficiency and aortic dilatation resulted in cardiac failure, decompensated with digitalisation and death occurred at the age of 4 months. This case represents the severe end of the clinical spectrum of Marfan syndrome, namely neonatal Marfan syndrome. Molecular diagnostic analyses confirmed a de novo exon 25 mutation in the FBN1 gene.

  20. [WT1 mutation as a cause of progressive nephropathy in Frasier syndrome--case report].

    Science.gov (United States)

    Wasilewska, Anna; Zoch-Zwierz, Walentyna; Tenderenda, Edyta; Rybi-Szumińska, Agnieszka; Kołodziejczyk, Zbigniew

    2009-06-01

    Frasier syndrome is an uncommon genetic disorder featuring progressive glomerulopathy, male pseudohermaphroditism and gonadal dysgenesis. It is caused by mutations in intron 9 of the WT1 gene. Because of its rarity there is limited literature available on the diagnosis and treatment of this syndrome. The aim of the study was to present the clinicopathological findings and molecular analysis of phenotypically female adolescent presenting with severe proteinuria and primary amenorrhea. The significance of early recognition of Frasier syndrome and its differentiation from Denys-Drash syndrome was discussed. WT1 mutation analysis should be routinely done in females with steroid-resistant nephritic syndrome.

  1. A recurring dominant negative mutation causes autosomal dominant growth hormone deficiency - a clinical research center study

    Energy Technology Data Exchange (ETDEWEB)

    Cogan, J.D.; Prince, M.; Phillips, J. [Vanderbilt Univ. School of Medicine, Nashville, TN (United States)] [and others

    1995-12-01

    Familial isolated GH deficiency type II (IGHD-II) is an autosomal dominant disorder that has been previously shown in some patients to be caused by heterogeneous GH gene defects that affect GH messenger RNA (mRNA) splicing. We report here our findings of multiple G{r_arrow}A transitions of the first base of the donor splice site of IVS 3 (+1G{r_arrow}A) in IGHD II subjects from three nonrelated kindreds from Sweden, North America, and South Africa. This + 1G{r_arrow}A substitution creates an NlaIII site that was used to demonstrate that all affected individuals in all three families were heterozygous for the mutation. To determine the effect of this mutation of GH mRNA processing, HeLa cells were transfected with expression plasmids containing normal or mutant +1G{r_arrow}A alleles, and complementary DNAs from the resulting GH mRNAs were sequenced. The mutation was found to destroy the GH IVS3 donor splice site, causing skipping of exon 3 and loss of the codons for amino acids 32-71 of the mature GH peptide from the mutant GH mRNA. Our finding of exon 3 skipping in transcripts of the +1G{r_arrow}A mutant allele is identical to our previous report of a different sixth base transition (+6T{r_arrow}C) mutation of the IVS 3 donor splice site that also causes IGHD II. Microsatellite analysis of an affected subjects` DNA from each of the three nonrelated kindreds indicates that the +1G{r_arrow}A mutation arose independently in each family. Finding that neither grandparent has the mutation in the first family suggests that it arose de novo in that family. Our data indicate that (1) +1G{r_arrow}A IVS 3 mutations perturb GH mRNA splicing and cause IGHD II; and (2) these mutations can present as de novo GHD cases. 13 refs., 4 figs., 1 tab.

  2. Two new mutations in the glucose-6-phosphatase gene cause glycogen storage disease in Hungarian patients.

    Science.gov (United States)

    Parvari, R; Lei, K J; Szonyi, L; Narkis, G; Moses, S; Chou, J Y

    1997-01-01

    Glycogen storage disease type 1a (von Gierke disease, GSD-1A) is caused by the deficiency of microsomal glucose-6-phosphatase (G6Pase) activity which catalyzes the final common step of glycogenolysis and gluconeogenesis. The cloning of the G6Pase cDNA and characterization of the human G6Pase gene enabled the identification of the mutations causing GSD-1a. This, in turn, allows the development of non-invasive DNA-based diagnosis that provides reliable carrier testing and prenatal diagnosis. Here we report on two new mutations E110Q and D38V causing GSD-1a in two Hungarian patients. The analyses of these mutations by site-directed mutagenesis followed by transient expression assays demonstrated that E110Q retains 17% of G6Pase enzymatic activity while the D38V abolishes the enzymatic activity. The patient with the E110Q has G222R as his other mutation. G222R was also shown to preserve about 4% of the G6Pase enzymatic activity. Nevertheless, the patient presented with the classical severe symptomatology of the GSD-1a.

  3. Severe combined immunodeficiency in Frisian Water Dogs caused by a RAG1 mutation.

    Science.gov (United States)

    Verfuurden, B; Wempe, F; Reinink, P; van Kooten, P J S; Martens, E; Gerritsen, R; Vos, J H; Rutten, V P M G; Leegwater, P A

    2011-06-01

    Mortality of pups at 8-12 weeks of age was frequently observed in Frisian Water Dogs. Blood parameters and clinical signs of newborns from three litters were monitored. Three pups from two litters showed strongly reduced levels of immunoglobulins and lymphocytes. These dogs were euthanized after first display of disease. Concurrent clinical and pathological features were consistent with a diagnosis of severe combined immunodeficiency (SCID). Defective V(D)J recombination is one of the causes of SCID in humans and animals. Eight genes involved in V(D)J recombination were investigated by segregation analysis of closely located microsatellite markers and by DNA sequence analysis. A nonsense mutation in the gene coding for V(D)J recombination factor RAG1 was identified in DNA from the cases at a position similar to that of nonsense mutations found in human SCID. It was concluded that SCID due to a mutation of RAG1 led to the high mortality.

  4. Transgenic rat model of neurodegeneration caused by mutation in the TDP gene.

    Science.gov (United States)

    Zhou, Hongxia; Huang, Cao; Chen, Han; Wang, Dian; Landel, Carlisle P; Xia, Pedro Yuxing; Bowser, Robert; Liu, Yong-Jian; Xia, Xu Gang

    2010-03-26

    TDP-43 proteinopathies have been observed in a wide range of neurodegenerative diseases. Mutations in the gene encoding TDP-43 (i.e., TDP) have been identified in amyotrophic lateral sclerosis (ALS) and in frontotemporal lobe degeneration associated with motor neuron disease. To study the consequences of TDP mutation in an intact system, we created transgenic rats expressing normal human TDP or a mutant form of human TDP with a M337V substitution. Overexpression of mutant, but not normal, TDP caused widespread neurodegeneration that predominantly affected the motor system. TDP mutation reproduced ALS phenotypes in transgenic rats, as seen by progressive degeneration of motor neurons and denervation atrophy of skeletal muscles. This robust rat model also recapitulated features of TDP-43 proteinopathies including the formation of TDP-43 inclusions, cytoplasmic localization of phosphorylated TDP-43, and fragmentation of TDP-43 protein. TDP transgenic rats will be useful for deciphering the mechanisms underlying TDP-43-related neurodegenerative diseases.

  5. Recurrent and founder mutations in the Netherlands: cardiac Troponin I (TNNI3) gene mutations as a cause of severe forms of hypertrophic and restrictive cardiomyopathy

    NARCIS (Netherlands)

    van den Wijngaard, A.; Volders, P.; van Tintelen, J. P.; Jongbloed, J. D. H.; van den Berg, M. P.; Lekanne Deprez, R. H.; Mannens, M. M. A. M.; Hofmann, N.; Slegtenhorst, M.; Dooijes, D.; Michels, M.; Arens, Y.; Jongbloed, R.; Smeets, B. J. M.

    2011-01-01

    Background About 2-7% of familial cardiomyopathy cases are caused by a mutation in the gene encoding cardiac troponin 1 (TNNI3). The related clinical phenotype is usually severe with early onset. Here we report on all currently known mutations in the Dutch population and compared these with those

  6. ITGB6 loss-of-function mutations cause autosomal recessive amelogenesis imperfecta.

    Science.gov (United States)

    Wang, Shih-Kai; Choi, Murim; Richardson, Amelia S; Reid, Bryan M; Lin, Brent P; Wang, Susan J; Kim, Jung-Wook; Simmer, James P; Hu, Jan C-C

    2014-04-15

    Integrins are cell-surface adhesion receptors that bind to extracellular matrices (ECM) and mediate cell-ECM interactions. Some integrins are known to play critical roles in dental enamel formation. We recruited two Hispanic families with generalized hypoplastic amelogenesis imperfecta (AI). Analysis of whole-exome sequences identified three integrin beta 6 (ITGB6) mutations responsible for their enamel malformations. The female proband of Family 1 was a compound heterozygote with an ITGB6 transition mutation in Exon 4 (g.4545G > A c.427G > A p.Ala143Thr) and an ITGB6 transversion mutation in Exon 6 (g.27415T > A c.825T > A p.His275Gln). The male proband of Family 2 was homozygous for an ITGB6 transition mutation in Exon 11 (g.73664C > T c.1846C > T p.Arg616*) and hemizygous for a transition mutation in Exon 6 of Nance-Horan Syndrome (NHS Xp22.13; g.355444T > C c.1697T > C p.Met566Thr). These are the first disease-causing ITGB6 mutations to be reported. Immunohistochemistry of mouse mandibular incisors localized ITGB6 to the distal membrane of differentiating ameloblasts and pre-ameloblasts, and then ITGB6 appeared to be internalized by secretory stage ameloblasts. ITGB6 expression was strongest in the maturation stage and its localization was associated with ameloblast modulation. Our findings demonstrate that early and late amelogenesis depend upon cell-matrix interactions. Our approach (from knockout mouse phenotype to human disease) demonstrates the power of mouse reverse genetics in mutational analysis of human genetic disorders and attests to the need for a careful dental phenotyping in large-scale knockout mouse projects.

  7. Novel mutations in EVC cause aberrant splicing in Ellis-van Creveld syndrome.

    Science.gov (United States)

    Shi, Lisong; Luo, Chunyan; Ahmed, Mairaj K; Attaie, Ali B; Ye, Xiaoqian

    2016-04-01

    Ellis-van Creveld syndrome (EvC) is a rare autosomal recessive disorder characterized by disproportionate chondrodysplasia, postaxial polydactyly, nail dystrophy, dental abnormalities and in a proportion of patients, congenital cardiac malformations. Weyers acrofacial dysostosis (Weyers) is another dominantly inherited disorder allelic to EvC syndrome but with milder phenotypes. Both disorders can result from loss-of-function mutations in either EVC or EVC2 gene, and phenotypes associated with the two gene mutations are clinically indistinguishable. We present here a clinical and molecular analysis of a Chinese family manifested specific features of EvC syndrome. Sequencing of both EVC and EVC2 identified two novel heterozygous splice site mutations c.384+5G>C in intron 3 and c.1465-1G>A in intron 10 in EVC, which were inherited from mother and father, respectively. In vitro minigene expression assay, RT-PCR and sequencing analysis demonstrated that c.384+5G>C mutation abolished normal splice site and created a new cryptic acceptor site within exon 4, whereas c.1465-1G>A mutation affected consensus splice junction site and resulted in full exon 11 skipping. These two aberrant pre-mRNA splicing processes both produced in-frame abnormal transcripts that possibly led to abolishment of important functional domains. To our knowledge, this is the first report of EVC mutations that cause EvC syndrome in Chinese population. Our data revealed that EVC splice site mutations altered splicing pattern and helped elucidate the pathogenesis of EvC syndrome.

  8. A KCNQ1 mutation causes age-dependant bradycardia and persistent atrial fibrillation.

    Science.gov (United States)

    Ki, Chang-Seok; Jung, Chae Lim; Kim, Hyun-ji; Baek, Kwan-Hyuck; Park, Seung Jung; On, Young Keun; Kim, Ki-Suk; Noh, Su Jin; Youm, Jae Boum; Kim, June Soo; Cho, Hana

    2014-03-01

    Atrial fibrillation (AF) is the most common arrhythmia. Gain-of-function mutations in KCNQ1, the pore-forming α-subunit of the slow delayed rectifier K current (IKs) channel, have been associated with AF. The purpose of this study was functional assessment of a mutation in KCNQ1 identified in a family with persistent AF and sinus bradycardia. We investigated whether this KCNQ1 missense mutation could form the genetic basis for AF and bradycardia simultaneously in this family. Sanger sequencing in a family with hereditary persistent AF identified a novel KCNQ1 variant (V241F) in a highly conserved region of S4 domain. The proband and her son developed bradycardia and persistent AF in an age-dependent fashion. The other son was a mutation carrier but he showed sinus bradycardia and not AF. Whole-cell patch clamp electrophysiology showed that V241F mutation in KCNQ1 shifted the activation curve to the left and dramatically slowed deactivation, leading to a constitutively open-like phenotype. Computer modeling showed that V241F would slow pacemaker activity. Also, simulations of atrial excitation predicted that V241F results in extreme shortening of action potential duration, possibly resulting in AF. Our study indicates that V241F might cause sinus bradycardia by increasing IKs. Additionally, V241F likely shortens atrial refractoriness to promote a substrate for reentry. KCNQ1 mutations have previously been described in AF, yet this is the first time a mutation in KCNQ1 is associated with age-dependent bradycardia and persistent AF. This finding further supports the hypothesis that sinus node dysfunction contributes to the development of AF.

  9. Mutations in SULT2B1 Cause Autosomal-Recessive Congenital Ichthyosis in Humans.

    Science.gov (United States)

    Heinz, Lisa; Kim, Gwang-Jin; Marrakchi, Slaheddine; Christiansen, Julie; Turki, Hamida; Rauschendorf, Marc-Alexander; Lathrop, Mark; Hausser, Ingrid; Zimmer, Andreas D; Fischer, Judith

    2017-06-01

    Ichthyoses are a clinically and genetically heterogeneous group of genodermatoses associated with abnormal scaling of the skin over the whole body. Mutations in nine genes are known to cause non-syndromic forms of autosomal-recessive congenital ichthyosis (ARCI). However, not all genetic causes for ARCI have been discovered to date. Using whole-exome sequencing (WES) and multigene panel screening, we identified 6 ARCI-affected individuals from three unrelated families with mutations in Sulfotransferase family 2B member 1 (SULT2B1), showing their causative association with ARCI. Cytosolic sulfotransferases form a large family of enzymes that are involved in the synthesis and metabolism of several steroids in humans. We identified four distinct mutations including missense, nonsense, and splice site mutations. We demonstrated the loss of SULT2B1 expression at RNA and protein levels in keratinocytes from individuals with ARCI by functional analyses. Furthermore, we succeeded in reconstructing the morphologic skin alterations in a 3D organotypic tissue culture model with SULT2B1-deficient keratinocytes and fibroblasts. By thin layer chromatography (TLC) of extracts from these organotypic cultures, we could show the absence of cholesterol sulfate, the metabolite of SULT2B1, and an increased level of cholesterol, indicating a disturbed cholesterol metabolism of the skin upon loss-of-function mutation in SULT2B1. In conclusion, our study reveals an essential role for SULT2B1 in the proper development of healthy human skin. Mutation in SULT2B1 leads to an ARCI phenotype via increased proliferation of human keratinocytes, thickening of epithelial layers, and altered epidermal cholesterol metabolism. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  10. Autosomal Dominant Hypoparathyroidism Caused by Germline Mutation in GNA11: Phenotypic and Molecular Characterization

    Science.gov (United States)

    Li, Dong; Opas, Evan E.; Tuluc, Florin; Metzger, Daniel L.; Hou, Cuiping; Hakonarson, Hakon

    2014-01-01

    Context: Most cases of autosomal dominant hypoparathyroidism (ADH) are caused by gain-of-function mutations in CASR or dominant inhibitor mutations in GCM2 or PTH. Objective: Our objectives were to identify the genetic basis for ADH in a multigenerational family and define the underlying disease mechanism. Subjects: Here we evaluated a multigenerational family with ADH in which affected subjects had normal sequences in these genes and were shorter than unaffected family members. Methods: We collected clinical and biochemical data from 6 of 11 affected subjects and performed whole-exome sequence analysis on DNA from two affected sisters and their affected father. Functional studies were performed after expression of wild-type and mutant Gα11 proteins in human embryonic kidney-293-CaR cells that stably express calcium-sensing receptors. Results: Whole-exome-sequencing followed by Sanger sequencing revealed a heterozygous mutation, c.179G>T; p.R60L, in GNA11, which encodes the α-subunit of G11, the principal heterotrimeric G protein that couples calcium-sensing receptors to signal activation in parathyroid cells. Functional studies of Gα11 R60L showed increased accumulation of intracellular concentration of free calcium in response to extracellular concentration of free calcium with a significantly decreased EC50 compared with wild-type Gα11. By contrast, R60L was significantly less effective than the oncogenic Q209L form of Gα11 as an activator of the MAPK pathway. Compared to subjects with CASR mutations, patients with GNA11 mutations lacked hypercalciuria and had normal serum magnesium levels. Conclusions: Our findings indicate that the germline gain-of-function mutation of GNA11 is a cause of ADH and implicate a novel role for GNA11 in skeletal growth. PMID:24823460

  11. 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. © The Author 2015. Published by Oxford University Press.

  12. Mutations in Dnaaf1 and Lrrc48 Cause Hydrocephalus, Laterality Defects, and Sinusitis in Mice

    Directory of Open Access Journals (Sweden)

    Seungshin Ha

    2016-08-01

    Full Text Available We have previously described a forward genetic screen in mice for abnormalities of brain development. Characterization of two hydrocephalus mutants by whole-exome sequencing after whole-genome SNP mapping revealed novel recessive mutations in Dnaaf1 and Lrrc48. Mouse mutants of these two genes have not been previously reported. The Dnaaf1 mutant carries a mutation at the splice donor site of exon 4, which results in abnormal transcripts. The Lrrc48 mutation is a missense mutation at a highly conserved leucine residue, which is also associated with a decrease in Lrrc48 transcription. Both Dnaaf1 and Lrrc48 belong to a leucine-rich repeat-containing protein family and are components of the ciliary axoneme. Their Chlamydomonas orthologs are known to be required for normal ciliary beat frequency or flagellar waveform, respectively. Some Dnaaf1 or Lrrc48 homozygote mutants displayed laterality defects, suggesting a motile cilia defect in the embryonic node. Mucus accumulation and neutrophil infiltration in the maxillary sinuses suggested sinusitis. Dnaaf1 mutants showed postnatal lethality, and none survived to weaning age. Lrrc48 mutants survive to adulthood, but had male infertility. ARL13B immunostaining showed the presence of motile cilia in the mutants, and the distal distribution of DNAH9 in the axoneme of upper airway motile cilia appeared normal. The phenotypic abnormalities suggest that mutations in Dnaaf1 and Lrrc48 cause defects in motile cilia function.

  13. De novo mutations in HCN1 cause early infantile epileptic encephalopathy.

    Science.gov (United States)

    Nava, Caroline; Dalle, Carine; Rastetter, Agnès; Striano, Pasquale; de Kovel, Carolien G F; Nabbout, Rima; Cancès, Claude; Ville, Dorothée; Brilstra, Eva H; Gobbi, Giuseppe; Raffo, Emmanuel; Bouteiller, Delphine; Marie, Yannick; Trouillard, Oriane; Robbiano, Angela; Keren, Boris; Agher, Dahbia; Roze, Emmanuel; Lesage, Suzanne; Nicolas, Aude; Brice, Alexis; Baulac, Michel; Vogt, Cornelia; El Hajj, Nady; Schneider, Eberhard; Suls, Arvid; Weckhuysen, Sarah; Gormley, Padhraig; Lehesjoki, Anna-Elina; De Jonghe, Peter; Helbig, Ingo; Baulac, Stéphanie; Zara, Federico; Koeleman, Bobby P C; Haaf, Thomas; LeGuern, Eric; Depienne, Christel

    2014-06-01

    Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels contribute to cationic Ih current in neurons and regulate the excitability of neuronal networks. Studies in rat models have shown that the Hcn1 gene has a key role in epilepsy, but clinical evidence implicating HCN1 mutations in human epilepsy is lacking. We carried out exome sequencing for parent-offspring trios with fever-sensitive, intractable epileptic encephalopathy, leading to the discovery of two de novo missense HCN1 mutations. Screening of follow-up cohorts comprising 157 cases in total identified 4 additional amino acid substitutions. Patch-clamp recordings of Ih currents in cells expressing wild-type or mutant human HCN1 channels showed that the mutations had striking but divergent effects on homomeric channels. Individuals with mutations had clinical features resembling those of Dravet syndrome with progression toward atypical absences, intellectual disability and autistic traits. These findings provide clear evidence that de novo HCN1 point mutations cause a recognizable early-onset epileptic encephalopathy in humans.

  14. Transient neonatal diabetes mellitus caused by a de novo ABCC8 gene mutation

    Directory of Open Access Journals (Sweden)

    Jung Hyun Kong

    2011-04-01

    Full Text Available Transient neonatal diabetes mellitus (TNDM is a rare form of diabetes mellitus that presents within the first 6 months of life with remission in infancy or early childhood. TNDM is mainly caused by anomalies in the imprinted region on chromosome 6q24; however, recently, mutations in the ABCC8 gene, which encodes sulfonylurea receptor 1 (SUR1, have also been implicated in TNDM. Herein, we present the case of a male child with TNDM whose mutational analysis revealed a heterozygous c.3547C&gt;T substitution in the ABCC8 gene, leading to an Arg1183Trp mutation in the SUR1 protein. The parents were clinically unaffected and did not show a mutation in the ABCC8 gene. This is the first case of a de novo ABCC8 gene mutation in a Korean patient with TNDM. The patient was initially treated with insulin and successfully switched to sulfonylurea therapy at 14 months of age. Remission of diabetes had occurred at the age of 16 months. Currently, the patient is 21 months old and is euglycemic without any insulin or oral hypoglycemic agents. His growth and physical development are normal, and there are no delays in achieving neurological and developmental milestones.

  15. Brief Report: IFIH1 Mutation Causes Systemic Lupus Erythematosus With Selective IgA Deficiency.

    Science.gov (United States)

    Van Eyck, Lien; De Somer, Lien; Pombal, Diana; Bornschein, Simon; Frans, Glynis; Humblet-Baron, Stéphanie; Moens, Leen; de Zegher, Francis; Bossuyt, Xavier; Wouters, Carine; Liston, Adrian

    2015-06-01

    To identify the underlying genetic defect in a 16-year-old girl with severe early-onset and refractory systemic lupus erythematosus (SLE), IgA deficiency, and mild lower limb spasticity without neuroradiologic manifestations. Whole-exome sequencing and extensive immunologic analysis were performed on samples from the index patient. We identified a de novo p.R779H IFIH1 gain-of-function mutation in a patient with severe early-onset SLE, selective IgA deficiency, and mild lower limb spasticity. The same mutation in IFIH1 was recently identified in patients with Aicardi-Goutières syndrome, a rare neuroimmunologic disorder associated with elevated levels of type I interferon (IFN). IFN induced with helicase C domain 1 functions as an intracellular innate immune receptor that senses viral nucleic acids and leads to the induction of type I IFN and proinflammatory cytokines. Despite systemic immunosuppressive treatment, disease activity persisted in the patient and was associated with elevated serum levels of IFNα and up-regulation of IFIH1 itself. This finding adds a new genetic causation for Mendelian lupus and greatly extends the disease spectrum associated with mutations in IFIH1 (ranging from inflammatory encephalopathy to prototypic systemic autoimmune disease). This marked phenotypic heterogeneity, despite an identical mutation, demonstrates the importance of modifying factors in type I IFN-dependent pathologies caused by mutations in IFIH1. © 2015, American College of Rheumatology.

  16. De Novo Mutations in CHAMP1 Cause Intellectual Disability with Severe Speech Impairment

    Science.gov (United States)

    Hempel, Maja; Cremer, Kirsten; Ockeloen, Charlotte W.; Lichtenbelt, Klaske D.; Herkert, Johanna C.; Denecke, Jonas; Haack, Tobias B.; Zink, Alexander M.; Becker, Jessica; Wohlleber, Eva; Johannsen, Jessika; Alhaddad, Bader; Pfundt, Rolph; Fuchs, Sigrid; Wieczorek, Dagmar; Strom, Tim M.; van Gassen, Koen L.I.; Kleefstra, Tjitske; Kubisch, Christian; Engels, Hartmut; Lessel, Davor

    2015-01-01

    CHAMP1 encodes a protein with a function in kinetochore-microtubule attachment and in the regulation of chromosome segregation, both of which are known to be important for neurodevelopment. By trio whole-exome sequencing, we have identified de novo deleterious mutations in CHAMP1 in five unrelated individuals affected by intellectual disability with severe speech impairment, motor developmental delay, muscular hypotonia, and similar dysmorphic features including short philtrum and a tented upper and everted lover lip. In addition to two frameshift and one nonsense mutations, we found an identical nonsense mutation, c.1192C>T (p.Arg398∗), in two affected individuals. All mutations, if resulting in a stable protein, are predicted to lead to the loss of the functionally important zinc-finger domains in the C terminus of the protein, which regulate CHAMP1 localization to chromosomes and the mitotic spindle, thereby providing a mechanistic understanding for their pathogenicity. We thus establish deleterious de novo mutations in CHAMP1 as a cause of intellectual disability. PMID:26340335

  17. Characterization of a novel founder MSH6 mutation causing Lynch syndrome in the French Canadian population.

    Science.gov (United States)

    Castellsagué, E; Liu, J; Volenik, A; Giroux, S; Gagné, R; Maranda, B; Roussel-Jobin, A; Latreille, J; Laframboise, R; Palma, L; Kasprzak, L; Marcus, V A; Breguet, M; Nolet, S; El-Haffaf, Z; Australie, K; Gologan, A; Aleynikova, O; Oros-Klein, K; Greenwood, C; Mes-Masson, A M; Provencher, D; Tischkowitz, M; Chong, G; Rousseau, F; Foulkes, W D

    2015-06-01

    We identified an MSH6 mutation (c.10C>T, p.Gln4*) causing Lynch syndrome (LS) in 11 French Canadian (FC) families from the Canadian province of Quebec. We aimed to investigate the molecular and clinical implications of this mutation among FC carriers and to assess its putative founder origin. We studied 11 probands and 27 family members. Additionally 6433 newborns, 187 colorectal cancer (CRC) cases, 381 endometrial cancer (EC) cases and 179 additional controls, all of them from Quebec, were used. Found in approximately 1 of 400 newborns, the mutation is one of the most common LS mutations described. We have found that this mutation confers a greater risk for EC than for CRC, both in the 11 studied families and in the unselected cases: EC [odds ratio (OR) = 7.5, p French settlers. Application of the results of this study could significantly improve the molecular testing and clinical management of LS families in Quebec. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Further evidence for GRIN2B mutation as the cause of severe epileptic encephalopathy.

    Science.gov (United States)

    Smigiel, Robert; Kostrzewa, Grazyna; Kosinska, Joanna; Pollak, Agnieszka; Stawinski, Piotr; Szmida, Elzbieta; Bloch, Michal; Szymanska, Krystyna; Karpinski, Pawel; Sasiadek, Maria M; Ploski, Rafal

    2016-12-01

    Epileptic encephalopathies (EE) include a range of severe epilepsies in which intractable seizures or severe sub-clinical epileptiform activity are accompanied by impairment of motor and cognitive functions. Mutations in several genes including ion channels and other genes whose function is not completely understood have been associated to some EE. In this report, we provide a detailed clinical description of a sporadic male patient with early-onset epilepsy and epileptic encephalopathy in whom we performed complete exome sequencing (WES) and identified a GRIN2B mutation. The GRIN2B splicing mutation in intron 10 (c.2011-1G>A) was revealed in a WES study. The result was confirmed by Sanger sequencing. No mutation was found in both parents. Our finding confirms that early-onset EE may be caused not only by gain-of-function variants but also by splice site mutations-in particular those affecting the splice acceptor site of the 10th intron of the GRIN2B gene. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  19. Cauli: a mouse strain with an Ift140 mutation that results in a skeletal ciliopathy modelling Jeune syndrome.

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    Kerry A Miller

    2013-08-01

    Full Text Available Cilia are architecturally complex organelles that protrude from the cell membrane and have signalling, sensory and motility functions that are central to normal tissue development and homeostasis. There are two broad categories of cilia; motile and non-motile, or primary, cilia. The central role of primary cilia in health and disease has become prominent in the past decade with the recognition of a number of human syndromes that result from defects in the formation or function of primary cilia. This rapidly growing class of conditions, now known as ciliopathies, impact the development of a diverse range of tissues including the neural axis, craniofacial structures, skeleton, kidneys, eyes and lungs. The broad impact of cilia dysfunction on development reflects the pivotal position of the primary cilia within a signalling nexus involving a growing number of growth factor systems including Hedgehog, Pdgf, Fgf, Hippo, Notch and both canonical Wnt and planar cell polarity. We have identified a novel ENU mutant allele of Ift140, which causes a mid-gestation embryonic lethal phenotype in homozygous mutant mice. Mutant embryos exhibit a range of phenotypes including exencephaly and spina bifida, craniofacial dysmorphism, digit anomalies, cardiac anomalies and somite patterning defects. A number of these phenotypes can be attributed to alterations in Hedgehog signalling, although additional signalling systems are also likely to be involved. We also report the identification of a homozygous recessive mutation in IFT140 in a Jeune syndrome patient. This ENU-induced Jeune syndrome model will be useful in delineating the origins of dysmorphology in human ciliopathies.

  20. Neonatal severe hyperparathyroidism caused by homozygous mutation in CASR: A rare cause of life-threatening hypercalcemia.

    Science.gov (United States)

    Murphy, Heidi; Patrick, Jessica; Báez-Irizarry, Eileen; Lacassie, Yves; Gómez, Ricardo; Vargas, Alfonso; Barkemeyer, Brian; Kanotra, Sohit; Zambrano, Regina M

    2016-04-01

    Neonatal severe hyperparathyroidism (NSHPT) is a rare, life-threatening condition that presents with severe hypercalcemia, hyperparathyroidism, and osteopenia in the newborn period. Treatment of NSHPT traditionally includes hydration and bisphosphonates; however newer calcimimetic agents, such as cinacalcet, are now being utilized to prevent or delay parathyroidectomy which is technically difficult in the newborn. Medical treatment success is related to calcium sensing receptor (CaSR) genotype. We report a 4-day-old infant who presented with hyperbilirubinemia, poor feeding, weight loss, severe hypotonia and was ultimately diagnosed with NSHPT. The patient's total serum calcium level of 36.8 mg/dL (reference range: 8.5-10.4 mg/dL) is, to our knowledge, the highest ever documented in this setting. Exome data previously obtained on the infant's parents was re-analyzed demonstrating bi-parental heterozygosity for a mutation of the CASR gene: c.206G > A, and Sanger sequencing data confirmed the patient was a homozygote for the same mutation. Though a patient with the same CaSR gene mutation described here has responded to cinacalcet, our patient did not respond and required parathyroidectomy. Though this case has previously been published as a surgical case report, a full report of the medical management and underlying genetic etiology is warranted; this case underscores the importance of disclosing bi-parental heterozygosity for a gene causing severe neonatal disease particularly when treatment is available and illustrates the need for further in vitro studies of this CaSR mutation. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. A frame-shift mutation of PMS2 is a widespread cause of Lynch syndrome

    DEFF Research Database (Denmark)

    Clendenning, Mark; Senter, Leigha; Hampel, Heather

    2008-01-01

    BACKGROUND: When compared to the other mismatch repair genes involved in Lynch syndrome, the identification of mutations within PMS2 has been limited (... are caused by PMS2. This disparity is primarily due to complications in the study of this gene caused by interference from pseudogene sequences. METHODS: Using a recently developed method for detecting PMS2 specific mutations, we have screened 99 patients who are likely candidates for PMS2 mutations based...

  2. Autosomal recessive retinitis pigmentosa caused by mutations in the MAK gene.

    Science.gov (United States)

    Stone, Edwin M; Luo, Xunda; Héon, Elise; Lam, Byron L; Weleber, Richard G; Halder, Jennifer A; Affatigato, Louisa M; Goldberg, Jacqueline B; Sumaroka, Alexander; Schwartz, Sharon B; Cideciyan, Artur V; Jacobson, Samuel G

    2011-12-28

    To determine the disease expression in autosomal recessive (ar) retinitis pigmentosa (RP) caused by mutations in the MAK (male germ cell-associated kinase) gene. Patients with RP and MAK gene mutations (n = 24; age, 32-77 years at first visit) were studied by ocular examination, perimetry, and optical coherence tomography (OCT). All but one MAK patient were homozygous for an identical truncating mutation in exon 9 and had Ashkenazi Jewish heritage. The carrier frequency of this mutation among 1207 unrelated Ashkenazi control subjects was 1 in 55, making it the most common cause of heritable retinal disease in this population and MAK-associated RP the sixth most common Mendelian disease overall in this group. Visual acuities could be normal into the eighth decade of life. Kinetic fields showed early loss in the superior-temporal quadrant. With more advanced disease, superior and midperipheral function was lost, but the nasal field remained. Only a central island was present at late stages. Pigmentary retinopathy was less prominent in the superior nasal quadrant. Rod-mediated vision was abnormal but detectable in the residual field; all patients had rod>cone dysfunction. Photoreceptor layer thickness was normal centrally but decreased with eccentricity. At the stages studied, there was no evidence of photoreceptor ciliary elongation. The patterns of disease expression in the MAK form of arRP showed some resemblance to patterns described in autosomal dominant RP, especially the form caused by RP1 mutations. The similarity in phenotypes is of interest, considering that there is experimental evidence of interaction between Mak and RP1 in the photoreceptor cilium.

  3. Homozygous and compound-heterozygous mutations in TGDS cause Catel-Manzke syndrome.

    Science.gov (United States)

    Ehmke, Nadja; Caliebe, Almuth; Koenig, Rainer; Kant, Sarina G; Stark, Zornitza; Cormier-Daire, Valérie; Wieczorek, Dagmar; Gillessen-Kaesbach, Gabriele; Hoff, Kirstin; Kawalia, Amit; Thiele, Holger; Altmüller, Janine; Fischer-Zirnsak, Björn; Knaus, Alexej; Zhu, Na; Heinrich, Verena; Huber, Celine; Harabula, Izabela; Spielmann, Malte; Horn, Denise; Kornak, Uwe; Hecht, Jochen; Krawitz, Peter M; Nürnberg, Peter; Siebert, Reiner; Manzke, Hermann; Mundlos, Stefan

    2014-12-04

    Catel-Manzke syndrome is characterized by Pierre Robin sequence and a unique form of bilateral hyperphalangy causing a clinodactyly of the index finger. We describe the identification of homozygous and compound heterozygous mutations in TGDS in seven unrelated individuals with typical Catel-Manzke syndrome by exome sequencing. Six different TGDS mutations were detected: c.892A>G (p.Asn298Asp), c.270_271del (p.Lys91Asnfs(∗)22), c.298G>T (p.Ala100Ser), c.294T>G (p.Phe98Leu), c.269A>G (p.Glu90Gly), and c.700T>C (p.Tyr234His), all predicted to be disease causing. By using haplotype reconstruction we showed that the mutation c.298G>T is probably a founder mutation. Due to the spectrum of the amino acid changes, we suggest that loss of function in TGDS is the underlying mechanism of Catel-Manzke syndrome. TGDS (dTDP-D-glucose 4,6-dehydrogenase) is a conserved protein belonging to the SDR family and probably plays a role in nucleotide sugar metabolism. Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  4. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. A recurrent de novo mutation in KCNC1 causes progressive myoclonus epilepsy

    DEFF Research Database (Denmark)

    Muona, M.; Berkovic, S. F.; Dibbens, L. M.

    2015-01-01

    Progressive myoclonus epilepsies (PMEs) are a group of rare, inherited disorders manifesting with action myoclonus, tonicclonic seizures and ataxia. We sequenced the exomes of 84 unrelated individuals with PME of unknown cause and molecularly solved 26 cases (31%). Remarkably, a recurrent de novo...... mutation, c. 959G>A (p.Arg320His), in KCNC1 was identified as a new major cause for PME. Eleven unrelated exome-sequenced (13%) and two affected individuals in a secondary cohort (7%) had this mutation. KCNC1 encodes K(V)3.1, a subunit of the K(V)3 voltage-gated potassium ion channels, which are major...... determinants of high-frequency neuronal firing. Functional analysis of the Arg320His mutant channel showed a dominant-negative loss-of-function effect. Ten cases had pathogenic mutations in known PME-associated genes (NEU1, NHLRC1, AFG3L2, EPM2A, CLN6 and SERPINI1). Identification of mutations in PRNP, SACS...

  6. Exploring the cause of drug resistance by the detrimental missense mutations in KIT receptor: computational approach.

    Science.gov (United States)

    Rajasekaran, R; Sethumadhavan, Rao

    2010-08-01

    In this work, we computationally identified the most detrimental missense mutations of KIT receptor causing gastrointestinal stromal tumors and analyzed the drug resistance of these missense mutations. Out of 31 missense mutations, 19 variants were commonly found less stable, deleterious and damaging by I-Mutant 2.0, SIFT and PolyPhen programs, respectively. Subsequently, we performed modeling of these 19 variants to understand their change in conformations with respect to native KIT receptor by computing their RMSD. Further, the native and 19 mutants were docked with the drug 'Imatinib' to explain the drug resistance of these detrimental missense mutations. Among the 19 mutants, we found by docking studies that 12 mutants, namely, F584C, F584L, V654A, L656P, T670I, R804W, D816F, D816V, D816Y, N822K, Y823D and E839K had less binding affinity with Imatinib than the native type. Finally, we analyzed that the loss of binding affinity of these 12 mutants, was due to altered flexibility in their binding amino acids with Imatinib as compared with native type by normal mode analysis. In our work, we found the novel data that the majority of the drug-binding amino acids in those 12 mutants had encountered loss of flexibility, which could be the theoretical basis for the cause of drug insensitivity.

  7. Mutations in the glutaminyl-tRNA synthetase gene cause early-onset epileptic encephalopathy.

    Science.gov (United States)

    Kodera, Hirofumi; Osaka, Hitoshi; Iai, Mizue; Aida, Noriko; Yamashita, Akio; Tsurusaki, Yoshinori; Nakashima, Mitsuko; Miyake, Noriko; Saitsu, Hirotomo; Matsumoto, Naomichi

    2015-02-01

    Aminoacylation is the process of attaching amino acids to their cognate tRNA, and thus is essential for the translation of mRNA into protein. This direct interaction of tRNA with amino acids is catalyzed by aminoacyl-tRNA synthetases. Using whole-exome sequencing, we identified compound heterozygous mutations [c.169T>C (p.Tyr57His) and c.1485dup (p.Lys496*)] in QARS, which encodes glutaminyl-tRNA synthetase, in two siblings with early-onset epileptic encephalopathy (EOEE). Recessive mutations in QARS, including the loss-of-function missense mutation p.Tyr57His, have been reported to cause intractable seizures with progressive microcephaly. The p.Lys496* mutation is novel and causes truncation of the QARS protein, leading to a deletion of part of the catalytic domain and the entire anticodon-binding domain. Transient expression of the p.Lys496* mutant in neuroblastoma 2A cells revealed diminished and aberrantly aggregated expression, indicating the loss-of-function nature of this mutant. Together with the previous report, our data suggest that abnormal aminoacylation is one of the underlying pathologies of EOEE.

  8. Mutation spectrum and genotype-phenotype correlation of hearing loss patients caused by SLC26A4 mutations in the Japanese: a large cohort study.

    Science.gov (United States)

    Miyagawa, Maiko; Nishio, Shin-Ya; Usami, Shin-Ichi

    2014-05-01

    Mutations in SLC26A4 cause a broad phenotypic spectrum, from typical Pendred syndrome to nonsyndromic hearing loss associated with enlarged vestibular aqueduct. Identification of these mutations is important for accurate diagnosis, proper medical management and appropriate genetic counseling and requires updated information regarding spectrum, clinical characteristics and genotype-phenotype correlations, based on a large cohort. In 100 patients with bilateral enlarged vestibular aqueduct among 1511 Japanese hearing loss probands registered in our gene bank, goiter data were available for 79, of whom 15 had Pendred syndrome and 64 had nonsyndromic hearing loss. We clarified the mutation spectrum for the SLC26A4 mutations and also summarized hearing levels, progression, fluctuation and existence of genotype-phenotype correlation. SLC26A4 mutations were identified in 82 of the 100 patients (82.0%). Of the Pendred syndrome patients, 93% (14/15) were carriers, as were 77% (49/64) of the nonsyndromic hearing loss patients. Clinical characteristics of patients with SLC26A4 mutations were congenital, fluctuating and progressive hearing loss usually associated with vertigo and/or goiter. We found no genotype-phenotype correlations, indicating that, unlike in the case of GJB2 mutations, the phenotype cannot be predicted from the genotype. Our mutation analysis confirmed the importance of mutations in the SLC26A4 gene among hearing loss patients with enlarged vestibular aqueduct and revealed the mutation spectrum, essential information when performing genetic testing.

  9. Loss-of-activity-mutation in the cardiac chloride-bicarbonate exchanger AE3 causes short QT syndrome

    DEFF Research Database (Denmark)

    Thorsen, Kasper; Dam, Vibeke S.; Kjaer-Sorensen, Kasper

    2017-01-01

    unrelated families with SQTS. The mutation causes reduced surface expression of AE3 and reduced membrane bicarbonate transport. Slc4a3 knockdown in zebrafish causes increased cardiac pHi, short QTc, and reduced systolic duration, which is rescued by wildtype but not mutated SLC4A3. Mechanistic analyses...

  10. Mutations in LRP5 cause primary osteoporosis without features of OI by reducing Wnt signaling activity

    Directory of Open Access Journals (Sweden)

    Korvala Johanna

    2012-04-01

    Full Text Available Abstract Background Primary osteoporosis is a rare childhood-onset skeletal condition whose pathogenesis has been largely unknown. We have previously shown that primary osteoporosis can be caused by heterozygous missense mutations in the Low-density lipoprotein receptor-related protein 5 (LRP5 gene, and the role of LRP5 is further investigated here. Methods LRP5 was analyzed in 18 otherwise healthy children and adolescents who had evidence of osteoporosis (manifested as reduced bone mineral density i.e. BMD, recurrent peripheral fractures and/or vertebral compression fractures but who lacked the clinical features of osteogenesis imperfecta (OI or other known syndromes linked to low BMD. Also 51 controls were analyzed. Methods used in the genetic analyses included direct sequencing and multiplex ligation-dependent probe amplification (MLPA. In vitro studies were performed using luciferase assay and quantitative real-time polymerase chain reaction (qPCR to examine the effect of two novel and three previously identified mutations on the activity of canonical Wnt signaling and on expression of tryptophan hydroxylase 1 (Tph1 and 5-hydroxytryptamine (5-Htr1b. Results Two novel LRP5 mutations (c.3446 T > A; p.L1149Q and c.3553 G > A; p.G1185R were identified in two patients and their affected family members. In vitro analyses showed that one of these novel mutations together with two previously reported mutations (p.C913fs, p.R1036Q significantly reduced the activity of the canonical Wnt signaling pathway. Such reductions may lead to decreased bone formation, and could explain the bone phenotype. Gut-derived Lrp5 has been shown to regulate serotonin synthesis by controlling the production of serotonin rate-limiting enzyme, Tph1. LRP5 mutations did not affect Tph1 expression, and only one mutant (p.L1149Q reduced expression of serotonin receptor 5-Htr1b (p Conclusions Our results provide additional information on the role of LRP5 mutations and their

  11. Mutations in LRP5 cause primary osteoporosis without features of OI by reducing Wnt signaling activity.

    Science.gov (United States)

    Korvala, Johanna; Jüppner, Harald; Mäkitie, Outi; Sochett, Etienne; Schnabel, Dirk; Mora, Stefano; Bartels, Cynthia F; Warman, Matthew L; Deraska, Donald; Cole, William G; Hartikka, Heini; Ala-Kokko, Leena; Männikkö, Minna

    2012-04-10

    Primary osteoporosis is a rare childhood-onset skeletal condition whose pathogenesis has been largely unknown. We have previously shown that primary osteoporosis can be caused by heterozygous missense mutations in the Low-density lipoprotein receptor-related protein 5 (LRP5) gene, and the role of LRP5 is further investigated here. LRP5 was analyzed in 18 otherwise healthy children and adolescents who had evidence of osteoporosis (manifested as reduced bone mineral density i.e. BMD, recurrent peripheral fractures and/or vertebral compression fractures) but who lacked the clinical features of osteogenesis imperfecta (OI) or other known syndromes linked to low BMD. Also 51 controls were analyzed. Methods used in the genetic analyses included direct sequencing and multiplex ligation-dependent probe amplification (MLPA). In vitro studies were performed using luciferase assay and quantitative real-time polymerase chain reaction (qPCR) to examine the effect of two novel and three previously identified mutations on the activity of canonical Wnt signaling and on expression of tryptophan hydroxylase 1 (Tph1) and 5-hydroxytryptamine (5-Htr1b). Two novel LRP5 mutations (c.3446 T > A; p.L1149Q and c.3553 G > A; p.G1185R) were identified in two patients and their affected family members. In vitro analyses showed that one of these novel mutations together with two previously reported mutations (p.C913fs, p.R1036Q) significantly reduced the activity of the canonical Wnt signaling pathway. Such reductions may lead to decreased bone formation, and could explain the bone phenotype. Gut-derived Lrp5 has been shown to regulate serotonin synthesis by controlling the production of serotonin rate-limiting enzyme, Tph1. LRP5 mutations did not affect Tph1 expression, and only one mutant (p.L1149Q) reduced expression of serotonin receptor 5-Htr1b (p LRP5 mutations and their effects on the development of juvenile-onset primary osteoporosis, and hence the pathogenesis of the disorder. The

  12. MBTPS2 mutations cause defective regulated intramembrane proteolysis in X-linked osteogenesis imperfecta

    Science.gov (United States)

    Lindert, Uschi; Cabral, Wayne A.; Ausavarat, Surasawadee; Tongkobpetch, Siraprapa; Ludin, Katja; Barnes, Aileen M.; Yeetong, Patra; Weis, Maryann; Krabichler, Birgit; Srichomthong, Chalurmpon; Makareeva, Elena N.; Janecke, Andreas R.; Leikin, Sergey; Röthlisberger, Benno; Rohrbach, Marianne; Kennerknecht, Ingo; Eyre, David R.; Suphapeetiporn, Kanya; Giunta, Cecilia; Marini, Joan C.; Shotelersuk, Vorasuk

    2016-01-01

    Osteogenesis imperfecta (OI) is a collagen-related bone dysplasia. We identified an X-linked recessive form of OI caused by defects in MBTPS2, which encodes site-2 metalloprotease (S2P). MBTPS2 missense mutations in two independent kindreds with moderate/severe OI cause substitutions at highly conserved S2P residues. Mutant S2P has normal stability, but impaired functioning in regulated intramembrane proteolysis (RIP) of OASIS, ATF6 and SREBP transcription factors, consistent with decreased proband secretion of type I collagen. Further, hydroxylation of the collagen lysine residue (K87) critical for crosslinking is reduced in proband bone tissue, consistent with decreased lysyl hydroxylase 1 in proband osteoblasts. Reduced collagen crosslinks presumptively undermine bone strength. Also, proband osteoblasts have broadly defective differentiation. These mutations provide evidence that RIP plays a fundamental role in normal bone development. PMID:27380894

  13. A novel SERPINA1 mutation causing serum alpha(1-antitrypsin deficiency.

    Directory of Open Access Journals (Sweden)

    Darren N Saunders

    Full Text Available Mutations in the SERPINA1 gene can cause deficiency in the circulating serine protease inhibitor α(1-Antitrypsin (α(1AT. α(1AT deficiency is the major contributor to pulmonary emphysema and liver disease in persons of European ancestry, with a prevalence of 1 in 2500 in the USA. We present the discovery and characterization of a novel SERPINA1 mutant from an asymptomatic Middle Eastern male with circulating α(1AT deficiency. This 49 base pair deletion mutation (T379Δ, originally mistyped by IEF, causes a frame-shift replacement of the last sixteen α(1AT residues and adds an extra twenty-four residues. Functional analysis showed that the mutant protein is not secreted and prone to intracellular aggregation.

  14. Mutations in the Human Ca{sup 2+}-sensing-receptor gene that cause familial hypocalciuric hypercalcemia

    Energy Technology Data Exchange (ETDEWEB)

    Yah-Huei Wu Chou [Chang Gung Memorial Hospital, Taoyuan (Taiwan, Province of China); Pollak, M.R.; Brown, E.M.; Seidman, J.G.; Seidman, C.E. [Harvard Univ., Boston, MA (United States); Brandi, M.L. [Univ. Florence (Italy); Toss, G.; Arnqvist, H. [Linkoping Univ. (Sweden)

    1995-05-01

    We report five novel mutations in the human Ca{sup 2+}-sensing-receptor gene that cause familial hypocalciuric hypercalcemia (FHH) or neonatal severe hyperparathyroidism. Each gene defect is a missense mutation that encodes a nonconservative amino acid alteration. These mutations are each predicted to be in the Ca{sup 2+}-sensing receptor`s large extracellular domain. In three families with FHH linked to the Ca{sup 2+}-sensing-receptor gene on chromosome 3 and in unrelated individuals probands with FHH, mutations were not detected in protein-coding sequences. On the basis of these data and previous analyses, we suggest that there are a wide range of mutations that cause FHH. Mutations that perturb the structure and function of the extracellular or transmembrane domains of the receptor and those that affect noncoding sequences of the Ca{sup 2+}-sensing-receptor gene can cause FHH. 23 refs., 2 figs., 1 tab.

  15. Treatable childhood neuronopathy caused by mutations in riboflavin transporter RFVT2

    Science.gov (United States)

    Foley, A. Reghan; Menezes, Manoj P.; Pandraud, Amelie; Gonzalez, Michael A.; Al-Odaib, Ahmad; Abrams, Alexander J.; Sugano, Kumiko; Yonezawa, Atsushi; Manzur, Adnan Y.; Burns, Joshua; Hughes, Imelda; McCullagh, B. Gary; Jungbluth, Heinz; Lim, Ming J.; Lin, Jean-Pierre; Megarbane, Andre; Urtizberea, J. Andoni; Shah, Ayaz H.; Antony, Jayne; Webster, Richard; Broomfield, Alexander; Ng, Joanne; Mathew, Ann A.; O’Byrne, James J.; Forman, Eva; Scoto, Mariacristina; Prasad, Manish; O’Brien, Katherine; Olpin, Simon; Oppenheim, Marcus; Hargreaves, Iain; Land, John M.; Wang, Min X.; Carpenter, Kevin; Horvath, Rita; Straub, Volker; Lek, Monkol; Gold, Wendy; Farrell, Michael O.; Brandner, Sebastian; Phadke, Rahul; Matsubara, Kazuo; McGarvey, Michael L.; Scherer, Steven S.; Baxter, Peter S.; King, Mary D.; Clayton, Peter; Rahman, Shamima; Reilly, Mary M.; Ouvrier, Robert A.; Christodoulou, John; Züchner, Stephan; Muntoni, Francesco

    2014-01-01

    Childhood onset motor neuron diseases or neuronopathies are a clinically heterogeneous group of disorders. A particularly severe subgroup first described in 1894, and subsequently called Brown-Vialetto-Van Laere syndrome, is characterized by progressive pontobulbar palsy, sensorineural hearing loss and respiratory insufficiency. There has been no treatment for this progressive neurodegenerative disorder, which leads to respiratory failure and usually death during childhood. We recently reported the identification of SLC52A2, encoding riboflavin transporter RFVT2, as a new causative gene for Brown-Vialetto-Van Laere syndrome. We used both exome and Sanger sequencing to identify SLC52A2 mutations in patients presenting with cranial neuropathies and sensorimotor neuropathy with or without respiratory insufficiency. We undertook clinical, neurophysiological and biochemical characterization of patients with mutations in SLC52A2, functionally analysed the most prevalent mutations and initiated a regimen of high-dose oral riboflavin. We identified 18 patients from 13 families with compound heterozygous or homozygous mutations in SLC52A2. Affected individuals share a core phenotype of rapidly progressive axonal sensorimotor neuropathy (manifesting with sensory ataxia, severe weakness of the upper limbs and axial muscles with distinctly preserved strength of the lower limbs), hearing loss, optic atrophy and respiratory insufficiency. We demonstrate that SLC52A2 mutations cause reduced riboflavin uptake and reduced riboflavin transporter protein expression, and we report the response to high-dose oral riboflavin therapy in patients with SLC52A2 mutations, including significant and sustained clinical and biochemical improvements in two patients and preliminary clinical response data in 13 patients with associated biochemical improvements in 10 patients. The clinical and biochemical responses of this SLC52A2-specific cohort suggest that riboflavin supplementation can

  16. Observational cohort study of ventricular arrhythmia in adults with Marfan syndrome caused by FBN1 mutations.

    Directory of Open Access Journals (Sweden)

    Ali Aydin

    Full Text Available Marfan syndrome is associated with ventricular arrhythmia but risk factors including FBN1 mutation characteristics require elucidation.We performed an observational cohort study of 80 consecutive adults (30 men, 50 women aged 42±15 years with Marfan syndrome caused by FBN1 mutations. We assessed ventricular arrhythmia on baseline ambulatory electrocardiography as >10 premature ventricular complexes per hour (>10 PVC/h, as ventricular couplets (Couplet, or as non-sustained ventricular tachycardia (nsVT, and during 31±18 months of follow-up as ventricular tachycardia (VT events (VTE such as sudden cardiac death (SCD, and sustained ventricular tachycardia (sVT. We identified >10 PVC/h in 28 (35%, Couplet/nsVT in 32 (40%, and VTE in 6 patients (8%, including 3 with SCD (4%. PVC>10/h, Couplet/nsVT, and VTE exhibited increased N-terminal pro-brain natriuretic peptide serum levels(P10/h and Couplet/nsVT also related to increased indexed end-systolic LV diameters (P = .024 and P = .020, to moderate mitral valve regurgitation (P = .018 and P = .003, and to prolonged QTc intervals (P = .001 and P = .006, respectively. Moreover, VTE related to mutations in exons 24-32 (P = .021. Kaplan-Meier analysis corroborated an association of VTE with increased NT-proBNP (P<.001 and with mutations in exons 24-32 (P<.001.Marfan syndrome with causative FBN1 mutations is associated with an increased risk for arrhythmia, and affected persons may require life-long monitoring. Ventricular arrhythmia on electrocardiography, signs of myocardial dysfunction and mutations in exons 24-32 may be risk factors of VTE.

  17. Confirmation of mutations in PROSC as a novel cause of vitamin B 6 -dependent epilepsy.

    Science.gov (United States)

    Plecko, Barbara; Zweier, Markus; Begemann, Anaïs; Mathis, Deborah; Schmitt, Bernhard; Striano, Pasquale; Baethmann, Martina; Vari, Maria Stella; Beccaria, Francesca; Zara, Federico; Crowther, Lisa M; Joset, Pascal; Sticht, Heinrich; Papuc, Sorina Mihaela; Rauch, Anita

    2017-12-01

    Vitamin-B 6 -dependent epilepsies are a heterogenous group of treatable disorders due to mutations in several genes ( ALDH7A1, PNPO, ALPL or ALDH4A1 ). In neonatal seizures, defects in ALDH7A1 and PNPO explain a major fraction of cases. Very recently biallelic mutations in PROSC were shown to be a novel cause in five families. We identified four further unrelated patients harbouring a total of six different mutations, including four novel disease mutations. Vitamin B 6 plasma profiles on pyridoxine did not enable the differentiation of patients with PROSC mutations. All four patients were normocephalic and had normal cranial imaging. Pyridoxine monotherapy allowed complete seizure control in one, while two patients had occasional febrile or afebrile seizures and one needed additional valproate therapy for photosensitive seizures. Two patients underwent a controlled pyridoxine withdrawal with signs of encephalopathy within a couple of days. Three had favourable outcome with normal intellectual properties at age 12.5, 15.5 and 30 years, respectively, while one child had marked developmental delay at age 27 months. The clinical and electroencephalographic phenotype in patients with PROSC mutations was indistinguishable from ALDH7A1 and PNPO deficiency. We therefore confirm PROSC as a novel gene for vitamin-B 6 -dependent epilepsy and delineate a non-specific plasma vitamin B 6 profile under pyridoxine treatment. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  18. Troponin Mutation Caused Diastolic Dysfunction and Experimental Treatment in Transgenic Mice with Cardiomyopathy.

    Science.gov (United States)

    Xu, Yang; Tian, Jie; Huang, Xupei

    2014-01-01

    Troponin, a contractile protein of the thin filament of striated muscle, consists of three subunits: troponin C (TnC), troponin T (TnT), and troponin I (TnI). Cardiac troponin I (cTnI) plays a critical role in regulation of cardiac function. The physiological effect of cTnI, as an inhibitory subunit of troponin complex, is to prevent the interaction between myosin heavy chain heads and actins, i.e. the cross-bridge formation, and to ensure a proper relaxation of cardiac myofilaments. In pathological conditions, the deficiency of cTnI or mutations in cTnI especially in the C-terminus of cTnI is associated with diastolic dysfunction caused by myofibril hypersensitivity to Ca 2+ . Our laboratory has generated cTnI knockout mouse model to investigate the cellular and molecular function of cTnI and created cTnI mutant disease mouse models to explore the pathophysiology caused by cTnI mutations in the heart. Here, we present our recent studies on physiological function of cTnI in the heart and the pathological consequences caused by the cTnI mutations in the diseased heart using the transgenic mouse models. The mechanisms underlying diastolic dysfunction and heart failure caused by cTnI mutations are explored in cell-based assays and in transgenic animal models. These studies provide us with useful information in searching for therapeutic strategies and target-oriented medication for the treatment of diastolic dysfunction and heart failure.

  19. Dystonia-Causing Mutations as a Contribution to the Etiology of Spasmodic Dysphonia.

    Science.gov (United States)

    de Gusmão, Claudio M; Fuchs, Tania; Moses, Andrew; Multhaupt-Buell, Trisha; Song, Phillip C; Ozelius, Laurie J; Franco, Ramon A; Sharma, Nutan

    2016-10-01

    Spasmodic dysphonia is a focal dystonia of the larynx with heterogeneous manifestations and association with familial risk factors. There are scarce data to allow precise understanding of etiology and pathophysiology. Screening for dystonia-causing genetic mutations has the potential to allow accurate diagnosis, inform about genotype-phenotype correlations, and allow a better understanding of mechanisms of disease. Cross-sectional study. Tertiary academic medical center. We enrolled patients presenting with spasmodic dysphonia to the voice clinic of our academic medical center. Data included demographics, clinical features, family history, and treatments administered. The following genes with disease-causing mutations previously associated with spasmodic dysphonia were screened: TOR1A (DYT1), TUBB4 (DYT4), and THAP1 (DYT6). Eighty-six patients were recruited, comprising 77% females and 23% males. A definite family history of neurologic disorder was present in 15% (13 of 86). Average age (± standard deviation) of symptom onset was 42.1 ± 15.7 years. Most (99%; 85 of 86) were treated with botulinum toxin, and 12% (11 of 86) received oral medications. Genetic screening was negative in all patients for the GAG deletion in TOR1A (DYT1) and in the 5 exons currently associated with disease-causing mutations in TUBB4 (DYT4). Two patients tested positive for novel/rare variants in THAP1 (DYT6). Genetic screening targeted at currently known disease-causing mutations in TOR1A, THAP1, and TUBB4 appears to have low diagnostic yield in sporadic spasmodic dysphonia. In our cohort, only 2 patients tested positive for novel/rare variants in THAP1. Clinicians should make use of genetic testing judiciously and in cost-effective ways. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

  20. Mutations in the DNA methyltransferase gene DNMT3A cause an overgrowth syndrome with intellectual disability

    DEFF Research Database (Denmark)

    Tatton-Brown, Katrina; Seal, Sheila; Ruark, Elise

    2014-01-01

    Overgrowth disorders are a heterogeneous group of conditions characterized by increased growth parameters and other variable clinical features such as intellectual disability and facial dysmorphism. To identify new causes of human overgrowth, we performed exome sequencing in ten proband...... and histone binding. Similar mutations were not present in 1,000 UK population controls (13/152 cases versus 0/1,000 controls; P intellectual disability and greater height. DNMT3A encodes a DNA methyltransferase essential for establishing...

  1. Constitutive insulin sensitivity and obesity my be caused by PTEN mutations

    Directory of Open Access Journals (Sweden)

    E A Pigarova

    2012-12-01

    Full Text Available Реферат по статье: Pal A, Barber TM, Van de Bunt M, Rudge SA, Zhang Q, Lachlan KL, Cooper NS, Linden H, Levy JC, Wakelam MJ, Walker L, Karpe F, Gloyn AL. PTEN mutations as a cause of constitutive insulin sensitivity and obesity. N Engl J Med. 2012 Sep 13;367(11:1002-11.

  2. A novel ICK mutation causes ciliary disruption and lethal endocrine-cerebro-osteodysplasia syndrome.

    Science.gov (United States)

    Oud, Machteld M; Bonnard, Carine; Mans, Dorus A; Altunoglu, Umut; Tohari, Sumanty; Ng, Alvin Yu Jin; Eskin, Ascia; Lee, Hane; Rupar, C Anthony; de Wagenaar, Nathalie P; Wu, Ka Man; Lahiry, Piya; Pazour, Gregory J; Nelson, Stanley F; Hegele, Robert A; Roepman, Ronald; Kayserili, Hülya; Venkatesh, Byrappa; Siu, Victoria M; Reversade, Bruno; Arts, Heleen H

    2016-01-01

    Endocrine-cerebro-osteodysplasia (ECO) syndrome [MIM:612651] caused by a recessive mutation (p.R272Q) in Intestinal cell kinase (ICK) shows significant clinical overlap with ciliary disorders. Similarities are strongest between ECO syndrome, the Majewski and Mohr-Majewski short-rib thoracic dysplasia (SRTD) with polydactyly syndromes, and hydrolethalus syndrome. In this study, we present a novel homozygous ICK mutation in a fetus with ECO syndrome and compare the effect of this mutation with the previously reported ICK variant on ciliogenesis and cilium morphology. Through homozygosity mapping and whole-exome sequencing, we identified a second variant (c.358G > T; p.G120C) in ICK in a Turkish fetus presenting with ECO syndrome. In vitro studies of wild-type and mutant mRFP-ICK (p.G120C and p.R272Q) revealed that, in contrast to the wild-type protein that localizes along the ciliary axoneme and/or is present in the ciliary base, mutant proteins rather enrich in the ciliary tip. In addition, immunocytochemistry revealed a decreased number of cilia in ICK p.R272Q-affected cells. Through identification of a novel ICK mutation, we confirm that disruption of ICK causes ECO syndrome, which clinically overlaps with the spectrum of ciliopathies. Expression of ICK-mutated proteins result in an abnormal ciliary localization compared to wild-type protein. Primary fibroblasts derived from an individual with ECO syndrome display ciliogenesis defects. In aggregate, our findings are consistent with recent reports that show that ICK regulates ciliary biology in vitro and in mice, confirming that ECO syndrome is a severe ciliopathy.

  3. 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.

  4. A novel missense mutation in oncostatin M receptor beta causing primary localized cutaneous amyloidosis.

    Science.gov (United States)

    Saeedi, Marjan; Ebrahim-Habibi, Azadeh; Haghighi, Alireza; Zarrabi, Fariba; Amoli, Mahsa M; Robati, Reza M

    2014-01-01

    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.

  5. A novel homozygous mutation causing hereditary tyrosinemia type I in yakut patient in russia: case report.

    Science.gov (United States)

    Maksimova, Nadezda R; Gurinova, Elizaveta E; Sukhomyasova, Aitalina L; Danilova, Anastasia L; Kaimonov, Vladimir S; Savvina, Mira T; Yakovleva, Aleksandra E; Alekseeva, Elena I

    2016-01-01

    Tyrosinemia type 1 (HT1) (OM IM 276700) is an inborn error of tyrosine catabolism caused be fumarylacetoacetate hedralase deficiency (FAH). In tyrosinemia type I, dietary therapy and nitisinone (Orfandin®), liver transplantation are effective . We present here the first report on identification of FAH mutation in HT1 Yakut patient from Russia with a novel one. The material for the clinical study is based on the genetic data of the patient card with tyrosinemia type 1, which is observed in the medical-genetic consultations Republican Hospital №1-National Medical Center of the Republic of Sakha (Yakutia). For molecular genetic analysis has been used venous whole blood, taken with the written consent from the patient, his relatives and 200 healthy Yakuts. All regions of the FAH gene spanning exons were amplified by PCR and mutational analyses was carried out by direct sequencing. Results of sequencing were confirmed by restriction fragment length polymorphism (PCR-RELF) analyses. 1 one-year-old child was identified with a diagnosis hereditary tyrosinemia type Ia, acute form. In exon 13 of the FAH gene a novel mutation c.1090 G>C (GLu364GLn) in the homozygous state was found in patient, and in heterozygous state in both parents. The child is treated Nitisinone therapy. DNA diagnostics of c.1090 G>C mutation frequency in the FAH gene was conducted using PCR and RFLP analysis in 200 unrelated Yakuts. The frequency of heterozygous carrier was 1.0%.

  6. Two single mutations commonly cause qualitative change of nonspecific carboxylesterases in insects.

    Science.gov (United States)

    Cui, Feng; Lin, Zhe; Wang, Hongsheng; Liu, Silu; Chang, Haijing; Reeck, Gerald; Qiao, Chuanling; Raymond, Michel; Kang, Le

    2011-01-01

    Carboxylesterases provide key mechanisms of resistance to insecticides, particularly organophosphates (OPs), in insects. One resistance mechanism is a qualitative change in the properties of a carboxylesterase. Two mutant forms, G151D and W271L, have been observed, mostly in dipteran species, to affect substrate specificity of enzymes. But whether these two single mutations can commonly change character of insect carboxylesterases is unknown. In our study carboxylesterase genes from seven insects distributed among four orders were cloned, mutated at position 151 or 271 and expressed in Escherichia coli. The kinetics of the purified recombinant proteins was examined towards an artificial carboxylester and two OP insecticides. The G/A151D and W271L mutation significantly reduced carboxylesterase activity in 87.5% and 100% cases, respectively, and at the same time conferred OP hydrolase activities in 62.5% and 87.5% cases, respectively. Thus, the change at position 271 is more effective to influence substrate specificity than that at position 151. These results may suggest that these two mutations have the potential to cause insecticide resistance broadly in insects. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Determining the Location of DNA Modification and Mutation Caused by UVB Light in Skin Cancer

    Science.gov (United States)

    2015-09-01

    were being administered. To address this we obtained an LED bulb from Qphotonics that emits light at 315nm ± 10 nm (10) and incorporated it into a...Award Number: W81XWH-12-1-0333 TITLE: Determining the Location of DNA Modification and Mutation Caused by UVB Light in Skin Cancer PRINCIPAL...Caused by UVB Light in Skin Cancer 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Monica Ransom, PhD Betty Diamond 5d. PROJECT NUMBER

  8. X-Linked Dyskeratosis Congenita Is Predominantly Caused by Missense Mutations in the DKC1 Gene

    OpenAIRE

    Knight, S.W.; Heiss, N.S.; Vulliamy, T.J.; Greschner, S.; Stavrides, G.; Pai, G.S.; Lestringant, G.; Varma, N.; Mason, P.J.; Dokal, I.; Poustka, A.

    1999-01-01

    Dyskeratosis congenita is a rare inherited bone marrow-failure syndrome characterized by abnormal skin pigmentation, nail dystrophy, and mucosal leukoplakia. More than 80% of patients develop bone-marrow failure, and this is the major cause of premature death. The X-linked form of the disease (MIM 305000) has been shown to be caused by mutations in the DKC1 gene. The gene encodes a 514-amino-acid protein, dyskerin, that is homologous to Saccharomyces cerevisiae Cbf5p and rat Nap57 proteins. B...

  9. Novel CACNA1S mutation causes autosomal dominant hypokalemic periodic paralysis in a Chinese family

    OpenAIRE

    Wang, Qiufen; Liu, Mugen; Xu, Chunsheng; Tang, Zhaohui; Liao, Yuhua; Du, Rong; Li, Wei; Wu, Xiaoyan; Wang, Xu; Liu, Ping; Zhang, Xianqin; Zhu, Jianfang; Ren, Xiang; Ke, Tie; Wang, Qing

    2005-01-01

    Hypokalemic periodic paralysis (HypoPP) is an autosomal dominant disorder which is characterized by periodic attacks of muscle weakness associated with a decrease in the serum potassium level. The skeletal muscle calcium channel α-subunit gene CACNA1S is a major disease-causing gene for HypoPP, however, only three specific HypoPP-causing mutations, Arg528His, Arg1,239His and Arg1,239Gly, have been identified in CACNA1S to date. In this study, we studied a four-generation Chinese family with H...

  10. Novel SIL1 mutations cause cerebellar ataxia and atrophy in a French-Canadian family.

    Science.gov (United States)

    Noreau, Anne; La Piana, Roberta; Marcoux, Camille; Dion, Patrick A; Brais, Bernard; Bernard, Geneviève; Rouleau, Guy A

    2015-10-01

    Two French-Canadian sibs with cerebellar ataxia and dysarthria were seen in our neurogenetics clinic. The older brother had global developmental delay and spastic paraplegia. Brain MRIs from these two affected individuals showed moderate to severe cerebellar atrophy. To identify the genetic basis for their disease, we conducted a whole exome sequencing (WES) investigation using genomic DNA prepared from the affected sibs and their healthy father. We identified two mutations in the SIL1 gene, which is reported to cause Marinesco-Sjögren syndrome. This study emphasizes how the diagnosis of patients with ataxic gait and cerebellar atrophy may benefit from WES to identify the genetic cause of their condition.

  11. A somatic mutation in erythro-myeloid progenitors causes neurodegenerative disease.

    Science.gov (United States)

    Mass, Elvira; Jacome-Galarza, Christian E; Blank, Thomas; Lazarov, Tomi; Durham, Benjamin H; Ozkaya, Neval; Pastore, Alessandro; Schwabenland, Marius; Chung, Young Rock; Rosenblum, Marc K; Prinz, Marco; Abdel-Wahab, Omar; Geissmann, Frederic

    2017-09-21

    The pathophysiology of neurodegenerative diseases is poorly understood and there are few therapeutic options. Neurodegenerative diseases are characterized by progressive neuronal dysfunction and loss, and chronic glial activation. Whether microglial activation, which is generally viewed as a secondary process, is harmful or protective in neurodegeneration remains unclear. Late-onset neurodegenerative disease observed in patients with histiocytoses, which are clonal myeloid diseases associated with somatic mutations in the RAS-MEK-ERK pathway such as BRAF(V600E), suggests a possible role of somatic mutations in myeloid cells in neurodegeneration. Yet the expression of BRAF(V600E) in the haematopoietic stem cell lineage causes leukaemic and tumoural diseases but not neurodegenerative disease. Microglia belong to a lineage of adult tissue-resident myeloid cells that develop during organogenesis from yolk-sac erythro-myeloid progenitors (EMPs) distinct from haematopoietic stem cells. We therefore hypothesized that a somatic BRAF(V600E) mutation in the EMP lineage may cause neurodegeneration. Here we show that mosaic expression of BRAF(V600E) in mouse EMPs results in clonal expansion of tissue-resident macrophages and a severe late-onset neurodegenerative disorder. This is associated with accumulation of ERK-activated amoeboid microglia in mice, and is also observed in human patients with histiocytoses. In the mouse model, neurobehavioural signs, astrogliosis, deposition of amyloid precursor protein, synaptic loss and neuronal death were driven by ERK-activated microglia and were preventable by BRAF inhibition. These results identify the fetal precursors of tissue-resident macrophages as a potential cell-of-origin for histiocytoses and demonstrate that a somatic mutation in the EMP lineage in mice can drive late-onset neurodegeneration. Moreover, these data identify activation of the MAP kinase pathway in microglia as a cause of neurodegeneration and this offers

  12. CAV3 mutations causing exercise intolerance, myalgia and rhabdomyolysis: Expanding the phenotypic spectrum of caveolinopathies.

    Science.gov (United States)

    Scalco, Renata Siciliani; Gardiner, Alice R; Pitceathly, Robert D S; Hilton-Jones, David; Schapira, Anthony H; Turner, Chris; Parton, Matt; Desikan, Mahalekshmi; Barresi, Rita; Marsh, Julie; Manzur, Adnan Y; Childs, Anne-Marie; Feng, Lucy; Murphy, Elaine; Lamont, Phillipa J; Ravenscroft, Gianina; Wallefeld, William; Davis, Mark R; Laing, Nigel G; Holton, Janice L; Fialho, Doreen; Bushby, Kate; Hanna, Michael G; Phadke, Rahul; Jungbluth, Heinz; Houlden, Henry; Quinlivan, Ros

    2016-08-01

    Rhabdomyolysis is often due to a combination of environmental trigger(s) and genetic predisposition; however, the underlying genetic cause remains elusive in many cases. Mutations in CAV3 lead to various neuromuscular phenotypes with partial overlap, including limb girdle muscular dystrophy type 1C (LGMD1C), rippling muscle disease, distal myopathy and isolated hyperCKemia. Here we present a series of eight patients from seven families presenting with exercise intolerance and rhabdomyolysis caused by mutations in CAV3 diagnosed by next generation sequencing (NGS) (n = 6). Symptoms included myalgia (n = 7), exercise intolerance (n = 7) and episodes of rhabdomyolysis (n = 2). Percussion-induced rapid muscle contractions (PIRCs) were seen in five out of six patients examined. A previously reported heterozygous mutation in CAV3 (p.T78M) and three novel variants (p.V14I, p.F41S, p.F54V) were identified. Caveolin-3 immunolabeling in muscle was normal in 3/4 patients; however, immunoblotting showed more than 50% reduction of caveolin-3 in five patients compared with controls. This case series demonstrates that exercise intolerance, myalgia and rhabdomyolysis may be caused by CAV3 mutations and broadens the phenotypic spectrum of caveolinopathies. In our series, immunoblotting was a more sensitive method to detect reduced caveolin-3 levels than immunohistochemistry in skeletal muscle. Patients presenting with muscle pain, exercise intolerance and rhabdomyolysis should be routinely tested for PIRCs as this may be an important clinical clue for caveolinopathies, even in the absence of other "typical" features. The use of NGS may expand current knowledge concerning inherited diseases, and unexpected/atypical phenotypes may be attributed to well-known human disease genes. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Two novel connexin32 mutations cause early onset X-linked Charcot-Marie-Tooth disease

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    Sand Jette C

    2007-07-01

    Full Text Available Abstract Background X-linked Charcot-Marie Tooth (CMT is caused by mutations in the connexin32 gene that encodes a polypeptide which is arranged in hexameric array and form gap junctions. Methods We describe two novel mutations in the connexin32 gene in two Norwegian families. Results Family 1 had a c.225delG (R75fsX83 which causes a frameshift and premature stop codon at position 247. This probably results in a shorter non-functional protein structure. Affected individuals had an early age at onset usually in the first decade. The symptoms were more severe in men than women. All had severe muscle weakness in the legs. Several abortions were observed in this family. Family 2 had a c.536 G>A (C179Y transition which causes a change of the highly conserved cysteine residue, i.e. disruption of at least one of three disulfide bridges. The mean age at onset was in the first decade. Muscle wasting was severe and correlated with muscle weakness in legs. The men and one woman also had symptom from their hands. The neuropathy is demyelinating and the nerve conduction velocities were in the intermediate range (25–49 m/s. Affected individuals had symmetrical clinical findings, while the neurophysiology revealed minor asymmetrical findings in nerve conduction velocity in 6 of 10 affected individuals. Conclusion The two novel mutations in the connexin32 gene are more severe than the majority of previously described mutations possibly due to the severe structural change of the gap junction they encode.

  14. Case reports of juvenile GM1 gangliosidosisis type II caused by mutation in GLB1 gene.

    Science.gov (United States)

    Karimzadeh, Parvaneh; Naderi, Samaneh; Modarresi, Farzaneh; Dastsooz, Hassan; Nemati, Hamid; Farokhashtiani, Tayebeh; Shamsian, Bibi Shahin; Inaloo, Soroor; Faghihi, Mohammad Ali

    2017-07-17

    Type II or juvenile GM1-gangliosidosis is an autosomal recessive lysosomal storage disorder, which is clinically distinct from infantile form of the disease by the lack of characteristic cherry-red spot and hepatosplenomegaly. The disease is characterized by slowly progressive neurodegeneration and mild skeletal changes. Due to the later age of onset and uncharacteristic presentation, diagnosis is frequently puzzled with other ataxic and purely neurological disorders. Up to now, 3-4 types of GM1-gangliosidosis have been reported and among them type I is the most common phenotype with the age of onset around 6 months. Various forms of GM1-gangliosidosis are caused by GLB1 gene mutations but severity of the disease and age of onset are directly related to the position and the nature of deleterious mutations. However, due to its unique genetic cause and overlapping clinical features, some researchers believe that GM1 gangliosidosis represents an overlapped disease spectrum instead of four distinct types. Here, we report a less frequent type of autosomal recessive GM1 gangliosidosis with perplexing clinical presentation in three families in the southwest part of Iran, who are unrelated but all from "Lurs" ethnic background. To identify disease-causing mutations, Whole Exome Sequencing (WES) utilizing next generation sequencing was performed. Four patients from three families were investigated with the age of onset around 3 years old. Clinical presentations were ataxia, gate disturbances and dystonia leading to wheelchair-dependent disability, regression of intellectual abilities, and general developmental regression. They all were born in consanguineous families with no previous documented similar disease in their parents. A homozygote missense mutation in GLB1 gene (c. 601 G > A, p.R201C) was found in all patients. Using Sanger sequencing this identified mutation was confirmed in the proband, their parents, grandparents, and extended family members, confirming

  15. [Diabetes mellitus caused by a mutation of glucokinase gene. Report of an affected family].

    Science.gov (United States)

    Pollak C, Felipe; Lagos L, Marcela; Santos M, José L; Poggi, Helena; Urzúa C, Abraham; Rumié C, Hana

    2017-09-01

    Maturity-Onset Diabetes of the Young (MODY) refers to a heterogeneous group of monogenic diabetes. Unlike other types of MODY characterized by genetic defects in transcription factors, MODY 2 is triggered by metabolic alterations caused by mutations of glucokinase (GCK), the first enzyme of the glycolytic pathway. We report a three-generation Chilean family with multiple cases affected with this disease. The index case is a patient who presented severe neonatal hyperglycemia (831 mg/dl, without ketosis) requiring continuous infusion of insulin, which was suspended after 48 hours with normalization of blood glucose. Subsequently, continuous glucose monitoring at 4 months of age revealed 47% of tissue glucose levels above 140 mg/dl, with fasting glucose levels between 120 and 166 mg/dl. The genetic analysis revealed a previously reported mutation in heterozygous state of the GCK gene (c.148C>T; p.His50Tyr). This mutation was also identified in more than one affected relative in the last two generations, with a transmission pattern suggestive of dominant inheritance. GCK gene sequencing led to a correct molecular diagnosis of MODY 2 while bioinformatic analysis indicated the possible molecular causes of the enzyme dysfunction. The knowledge of the molecular diagnosis allowed an adequate medical treatment for this disease.

  16. S149R, a novel mutation in the ABCD1 gene causing X-linked adrenoleukodystrophy

    Science.gov (United States)

    Ying, Hui; Li, Hongyu; Chen, Jing; Xu, Chao

    2017-01-01

    X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder. It is a heterogeneous disorder caused by mutations in the ATP-binding cassette protein subfamily D1 (ABCD1) gene, encoding the peroxisomal membrane protein ALDP, which is involved in the transmembrane transport of very long-chain fatty acids. For the first time, we report a case of olivopontocerebellar X-ALD on the Chinese mainland. In this study, a novel mutation (c.447T>A; p.S149R) in ABCD1 was detected in a patient diagnosed with X-ALD. The mutant amino acid is well conserved among species. Bioinformatics analysis predicted the substitution to be deleterious and to cause structural changes in the adrenoleukodystrophy protein. Immunofluorescence showed an altered subcellular localization of the S149R mutant protein, which may lead to defects in the degradation of very long chain fatty acids in peroxisomes. We therefore suggest that the novel mutation, which alters ALDP structure, subcellular distribution and function, is responsible for X-ALD. PMID:29152099

  17. Homozygous ARHGEF2 mutation causes intellectual disability and midbrain-hindbrain malformation.

    Directory of Open Access Journals (Sweden)

    Ethiraj Ravindran

    2017-04-01

    Full Text Available Mid-hindbrain malformations can occur during embryogenesis through a disturbance of transient and localized gene expression patterns within these distinct brain structures. Rho guanine nucleotide exchange factor (ARHGEF family members are key for controlling the spatiotemporal activation of Rho GTPase, to modulate cytoskeleton dynamics, cell division, and cell migration. We identified, by means of whole exome sequencing, a homozygous frameshift mutation in the ARHGEF2 as a cause of intellectual disability, a midbrain-hindbrain malformation, and mild microcephaly in a consanguineous pedigree of Kurdish-Turkish descent. We show that loss of ARHGEF2 perturbs progenitor cell differentiation and that this is associated with a shift of mitotic spindle plane orientation, putatively favoring more symmetric divisions. The ARHGEF2 mutation leads to reduction in the activation of the RhoA/ROCK/MLC pathway crucial for cell migration. We demonstrate that the human brain malformation is recapitulated in Arhgef2 mutant mice and identify an aberrant migration of distinct components of the precerebellar system as a pathomechanism underlying the midbrain-hindbrain phenotype. Our results highlight the crucial function of ARHGEF2 in human brain development and identify a mutation in ARHGEF2 as novel cause of a neurodevelopmental disorder.

  18. Gain-of-function FHF1 mutation causes early-onset epileptic encephalopathy with cerebellar atrophy.

    Science.gov (United States)

    Siekierska, Aleksandra; Isrie, Mala; Liu, Yue; Scheldeman, Chloë; Vanthillo, Niels; Lagae, Lieven; de Witte, Peter A M; Van Esch, Hilde; Goldfarb, Mitchell; Buyse, Gunnar M

    2016-06-07

    Voltage-gated sodium channel (Nav)-encoding genes are among early-onset epileptic encephalopathies (EOEE) targets, suggesting that other genes encoding Nav-binding proteins, such as fibroblast growth factor homologous factors (FHFs), may also play roles in these disorders. To identify additional genes for EOEE, we performed whole-exome sequencing in a family quintet with 2 siblings with a lethal disease characterized by EOEE and cerebellar atrophy. The pathogenic nature and functional consequences of the identified sequence alteration were determined by electrophysiologic studies in vitro and in vivo. A de novo heterozygous missense mutation was identified in the FHF1 gene (FHF1AR114H, FHF1BR52H) in the 2 affected siblings. The mutant FHF1 proteins had a strong gain-of-function phenotype in transfected Neuro2A cells, enhancing the depolarizing shifts in Nav1.6 voltage-dependent fast inactivation, predicting increased neuronal excitability. Surprisingly, the gain-of-function effect is predicted to result from weaker interaction of mutant FHF1 with the Nav cytoplasmic tail. Transgenic overexpression of mutant FHF1B in zebrafish larvae enhanced epileptiform discharges, demonstrating the epileptic potential of this FHF1 mutation in the affected children. Our data demonstrate that gain-of-function FHF mutations can cause neurologic disorder, and expand the repertoire of genetic causes (FHF1) and mechanisms (altered Nav gating) underlying EOEE and cerebellar atrophy. © 2016 American Academy of Neurology.

  19. A GDF5 point mutation strikes twice--causing BDA1 and SYNS2.

    Directory of Open Access Journals (Sweden)

    Elisa Degenkolbe

    Full Text Available Growth and Differentiation Factor 5 (GDF5 is a secreted growth factor that belongs to the Bone Morphogenetic Protein (BMP family and plays a pivotal role during limb development. GDF5 is a susceptibility gene for osteoarthritis (OA and mutations in GDF5 are associated with a wide variety of skeletal malformations ranging from complex syndromes such as acromesomelic chondrodysplasias to isolated forms of brachydactylies or multiple synostoses syndrome 2 (SYNS2. Here, we report on a family with an autosomal dominant inherited combination of SYNS2 and additional brachydactyly type A1 (BDA1 caused by a single point mutation in GDF5 (p.W414R. Functional studies, including chondrogenesis assays with primary mesenchymal cells, luciferase reporter gene assays and Surface Plasmon Resonance analysis, of the GDF5(W414R variant in comparison to other GDF5 mutations associated with isolated BDA1 (p.R399C or SYNS2 (p.E491K revealed a dual pathomechanism characterized by a gain- and loss-of-function at the same time. On the one hand insensitivity to the main GDF5 antagonist NOGGIN (NOG leads to a GDF5 gain of function and subsequent SYNS2 phenotype. Whereas on the other hand, a reduced signaling activity, specifically via the BMP receptor type IA (BMPR1A, is likely responsible for the BDA1 phenotype. These results demonstrate that one mutation in the overlapping interface of antagonist and receptor binding site in GDF5 can lead to a GDF5 variant with pathophysiological relevance for both, BDA1 and SYNS2 development. Consequently, our study assembles another part of the molecular puzzle of how loss and gain of function mutations in GDF5 affect bone development in hands and feet resulting in specific types of brachydactyly and SYNS2. These novel insights into the biology of GDF5 might also provide further clues on the pathophysiology of OA.

  20. UBIAD1 mutation alters a mitochondrial prenyltransferase to cause Schnyder corneal dystrophy.

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    Michael L Nickerson

    2010-05-01

    Full Text Available Mutations in a novel gene, UBIAD1, were recently found to cause the autosomal dominant eye disease Schnyder corneal dystrophy (SCD. SCD is characterized by an abnormal deposition of cholesterol and phospholipids in the cornea resulting in progressive corneal opacification and visual loss. We characterized lesions in the UBIAD1 gene in new SCD families and examined protein homology, localization, and structure.We characterized five novel mutations in the UBIAD1 gene in ten SCD families, including a first SCD family of Native American ethnicity. Examination of protein homology revealed that SCD altered amino acids which were highly conserved across species. Cell lines were established from patients including keratocytes obtained after corneal transplant surgery and lymphoblastoid cell lines from Epstein-Barr virus immortalized peripheral blood mononuclear cells. These were used to determine the subcellular localization of mutant and wild type protein, and to examine cholesterol metabolite ratios. Immunohistochemistry using antibodies specific for UBIAD1 protein in keratocytes revealed that both wild type and N102S protein were localized sub-cellularly to mitochondria. Analysis of cholesterol metabolites in patient cell line extracts showed no significant alteration in the presence of mutant protein indicating a potentially novel function of the UBIAD1 protein in cholesterol biochemistry. Molecular modeling was used to develop a model of human UBIAD1 protein in a membrane and revealed potentially critical roles for amino acids mutated in SCD. Potential primary and secondary substrate binding sites were identified and docking simulations indicated likely substrates including prenyl and phenolic molecules.Accumulating evidence from the SCD familial mutation spectrum, protein homology across species, and molecular modeling suggest that protein function is likely down-regulated by SCD mutations. Mitochondrial UBIAD1 protein appears to have a highly

  1. A novel nonsense mutation in keratin 10 causes a familial case of recessive epidermolytic ichthyosis

    Science.gov (United States)

    Gutierrez, Jeydith A; Hannoush, Zeina C; Vargas, Luis G; Momany, Allison; Garcia, Carmen C; Murray, Jeffrey C; Dunnwald, Martine

    2013-01-01

    Epidermolytic ichthyosis (EI) is a rare skin disorder characterized by generalized erythroderma and cutaneous blistering at birth, which is substituted by hyperkeratosis later in life. It is caused by autosomal dominant mutations in highly conserved regions of KRT1 and KRT10. To date, only four mutations with autosomal recessive inheritance of EI have been described in consanguineous families. All of them affect the 2B domain of KRT10. In the present study, we describe four patients with EI (including one lethal case) born from unaffected parents in a consanguineous family of a native Venezuelan community. The objective of this study was to characterize the clinical, genetic, and morphological aspects of the disease in this family, as well as understand its functional implications. Genomic DNA was sequenced for KRT10 and KRT1. Immunofluoresence for keratin expression was performed on cutaneous biopsies. After examination of cutaneous biopsies histology, our results showed hyperkeratosis and acantholysis with an expanded granular layer. Sequencing of KRT10 demonstrated a nonsense mutation (p.Tyr282Ter.) corresponding to the 1B domain of the protein in patients and a heterozygous pattern in other family members, resulting in complete absence of K10. The loss of K10 was compensated by upregulation of K14 and K17. In conclusion, this novel mutation in KRT10 is the first recessive genetic variation that is not located in the so called “hot spot” for recessive EI, suggesting that other areas of the gene are also susceptible for such mutations. PMID:23957016

  2. Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis

    Science.gov (United States)

    Gomez-Ospina, Natalia; Potter, Carol J.; Xiao, Rui; Manickam, Kandamurugu; Kim, Mi-Sun; Kim, Kang Ho; Shneider, Benjamin L.; Picarsic, Jennifer L.; Jacobson, Theodora A.; Zhang, Jing; He, Weimin; Liu, Pengfei; Knisely, A. S.; Finegold, Milton J.; Muzny, Donna M.; Boerwinkle, Eric; Lupski, James R.; Plon, Sharon E.; Gibbs, Richard A.; Eng, Christine M.; Yang, Yaping; Washington, Gabriel C.; Porteus, Matthew H.; Berquist, William E.; Kambham, Neeraja; Singh, Ravinder J.; Xia, Fan; Enns, Gregory M.; Moore, David D.

    2016-01-01

    Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection. PMID:26888176

  3. Ataxia and Hypogonadotropic Hypogonadism with Intrafamilial Variability Caused by RNF216 Mutation.

    Science.gov (United States)

    Alqwaifly, Mohammed; Bohlega, Saeed

    2016-06-15

    Gordon Holmes syndrome (GHS) is a distinct phenotype of autosomal recessive cerebellar ataxia, characterized by ataxia, dementia, reproductive defects and hypogonadism; it has been recently found to be associated with RNF216 mutation. We performed whole-exome sequencing and filtered the resulting novel variants by the coordinates of the shared autozygome. We identified a novel splicing variant in RNF216 that is likely to abolish the canonical splice site at the junction of exon/intron 13 (NM_207111.3:c.2061G>A). We herein report two patients with GHS caused by a novel RNF216 mutation as the first follow up report on RNF216-related GHS, and show interfamilial variability of phenotype supporting the previously reported RNF216-related cases.

  4. Ataxia and hypogonadotropic hypogonadism with intrafamilial variability caused by RNF216 mutation

    Directory of Open Access Journals (Sweden)

    Mohammed Alqwaifly

    2016-06-01

    Full Text Available Gordon Holmes syndrome (GHS is a distinct phenotype of autosomal recessive cerebellar ataxia, characterized by ataxia, dementia, reproductive defects and hypogonadism; it has been recently found to be associated with RNF216 mutation. We performed whole-exome sequencing and filtered the resulting novel variants by the coordinates of the shared autozygome. We identified a novel splicing variant in RNF216 that is likely to abolish the canonical splice site at the junction of exon/intron 13 (NM_207111.3:c.2061G>A. We herein report two patients with GHS caused by a novel RNF216 mutation as the first follow up report on RNF216-related GHS, and show interfamilial variability of phenotype supporting the previously reported RNF216-related cases.

  5. Waardenburg syndrome: a rare cause of inherited neuropathy due to SOX10 mutation.

    Science.gov (United States)

    Bogdanova-Mihaylova, Petya; Alexander, Michael D; Murphy, Raymond P J; Murphy, Sinéad M

    2017-09-01

    Waardenburg syndrome (WS) is a rare disorder comprising sensorineural deafness and pigmentation abnormalities. Four distinct subtypes are defined based on the presence or absence of additional symptoms. Mutations in six genes have been described in WS. SOX10 mutations are usually associated with a more severe phenotype of WS with peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, and Hirschsprung disease. Here we report a 32-year-old man with a novel heterozygous missense variant in SOX10 gene, who presented with congenital deafness, Hirschsprung disease, iris heterochromia, foot deformity, and intermediate conduction velocity length-dependent sensorimotor neuropathy. This case highlights that the presence of other non-neuropathic features in a patient with presumed hereditary neuropathy should alert the clinician to possible atypical rare causes. © 2017 Peripheral Nerve Society.

  6. Two missense mutations in KCNQ1 cause pituitary hormone deficiency and maternally inherited gingival fibromatosis

    DEFF Research Database (Denmark)

    Tommiska, Johanna; Känsäkoski, Johanna; Skibsbye, Lasse

    2017-01-01

    unrelated families harbor either of two missense mutations, c.347G>T p.(Arg116Leu) or c.1106C>T p.(Pro369Leu), in KCNQ1, a gene previously implicated in the long QT interval syndrome. Kcnq1 is expressed in hypothalamic GHRH neurons and pituitary somatotropes. Co-expressing KCNQ1 with the KCNE2 β......-subunit shows that both KCNQ1 mutants increase current levels in patch clamp analyses and are associated with reduced pituitary hormone secretion from AtT-20 cells. In conclusion, our results reveal a role for the KCNQ1 potassium channel in the regulation of human growth, and show that growth hormone deficiency...... associated with maternally inherited gingival fibromatosis is an allelic disorder with cardiac arrhythmia syndromes caused by KCNQ1 mutations....

  7. A novel mutation in the SH3BP2 gene causes cherubism: case report

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    Yu Shi-Feng

    2006-12-01

    Full Text Available Abstract Background Cherubism is a rare hereditary multi-cystic disease of the jaws, characterized by its typical appearance in early childhood, and stabilization and remission after puberty. It is genetically transmitted in an autosomal dominant fashion and the gene coding for SH3-binding protein 2 (SH3BP2 may be involved. Case presentation We investigated a family consisting of 21 members with 3 female affected individuals with cherubism from Northern China. Of these 21 family members, 17 were recruited for the genetic analysis. We conducted the direct sequence analysis of the SH3BP2 gene among these 17 family members. A disease-causing mutation was identified in exon 9 of the gene. It was an A1517G base change, which leads to a D419G amino acid substitution. Conclusion To our knowledge, the A1517G mutation has not been reported previously in cherubism. This finding is novel.

  8. A connexin 26 mutation causes a syndrome of sensorineural hearing loss and palmoplantar hyperkeratosis (MIM 148350)

    OpenAIRE

    Heathcote, K.; Syrris, P.; Carter, N.; Patton, M.

    2000-01-01

    We report a missense mutation in the connexin 26 gene (GJB2) in a family with an autosomal dominant syndrome of hearing loss and hyperkeratosis. The affected family members have high frequency, slowly progressive, bilateral, sensorineural hearing loss and palmoplantar hyperkeratosis. The mutation causes an amino acid substitution (G59A), which may disrupt a reverse turn in the first extracellular loop of connexin 26. Connexin 26 mutations have been reported in syndromes of deafness and palmop...

  9. Mutations in the glucose-6-phosphatase gene that cause glycogen storage disease type 1a

    Energy Technology Data Exchange (ETDEWEB)

    Chou, J.Y.; Lei, K.J.; Shelly, L.L. [National Institutes of Health, Bethesda, MD (United States)

    1994-09-01

    Glycogen storage disease (GSD) type la (von Gierke disease) is caused by the deficiency of glucose-6-phosphatase (G6Pase), the key enzyme in glucose homeostasis. The disease presents with clinical manifestations of severe hypoglycemia, hepatomegaly, growth retardation, lactic acidemia, hyperlipidemia, and hyperuricemia. We have succeeded in isolating a murine G6Pase cDNA from a normal mouse liver cDNA library by differentially screening method. We then isolated the human G6Pase cDNA and gene. To date, we have characterized the G6Pase genes of twelve GSD type la patients and uncovered a total of six different mutations. The mutations are comprised of R83C (an Arg at codon 83 to a Cys), Q347X (a Gly at codon 347 to a stop codon), 459insTA (a two basepair insertion at nucleotide 459 yielding a truncated G6Pase of 129 residues), R295C (an Arg at codon 295 to a Cys), G222R (a Gly at codon 222 to an Arg) and {delta}F327 (a codon deletion for Phe-327 at nucleotides 1058 to 1060). The relative incidences of these mutations are 37.5% (R83C), 33.3% (Q347X), 16.6% (459insTA), 4.2% (G222R), 4.2% (R295C) and 4.2% ({delta}F327). Site-directed mutagenesis and transient expression assays demonstrated that the R83C, Q347X, R295C, and {delta}F327 mutations abolished whereas the G222R mutation greatly reduced G6Pase activity. We further characterized the structure-function requirements of amino acids 83, 222, and 295 in G6Pase catalysis. The identification of mutations in GSD type la patients has unequivocally established the molecular basis of the type la disorder. Knowledge of the mutations may be applied to prenatal diagnosis and opens the way for developing and evaluating new therapeutic approaches.

  10. Myopathic lamin mutations cause reductive stress and activate the nrf2/keap-1 pathway.

    Directory of Open Access Journals (Sweden)

    George Dialynas

    2015-05-01

    Full Text Available Mutations in the human LMNA gene cause muscular dystrophy by mechanisms that are incompletely understood. The LMNA gene encodes A-type lamins, intermediate filaments that form a network underlying the inner nuclear membrane, providing structural support for the nucleus and organizing the genome. To better understand the pathogenesis caused by mutant lamins, we performed a structural and functional analysis on LMNA missense mutations identified in muscular dystrophy patients. These mutations perturb the tertiary structure of the conserved A-type lamin Ig-fold domain. To identify the effects of these structural perturbations on lamin function, we modeled these mutations in Drosophila Lamin C and expressed the mutant lamins in muscle. We found that the structural perturbations had minimal dominant effects on nuclear stiffness, suggesting that the muscle pathology was not accompanied by major structural disruption of the peripheral nuclear lamina. However, subtle alterations in the lamina network and subnuclear reorganization of lamins remain possible. Affected muscles had cytoplasmic aggregation of lamins and additional nuclear envelope proteins. Transcription profiling revealed upregulation of many Nrf2 target genes. Nrf2 is normally sequestered in the cytoplasm by Keap-1. Under oxidative stress Nrf2 dissociates from Keap-1, translocates into the nucleus, and activates gene expression. Unexpectedly, biochemical analyses revealed high levels of reducing agents, indicative of reductive stress. The accumulation of cytoplasmic lamin aggregates correlated with elevated levels of the autophagy adaptor p62/SQSTM1, which also binds Keap-1, abrogating Nrf2 cytoplasmic sequestration, allowing Nrf2 nuclear translocation and target gene activation. Elevated p62/SQSTM1 and nuclear enrichment of Nrf2 were identified in muscle biopsies from the corresponding muscular dystrophy patients, validating the disease relevance of our Drosophila model. Thus, novel

  11. Kufs disease, the major adult form of neuronal ceroid lipofuscinosis, caused by mutations in CLN6.

    LENUS (Irish Health Repository)

    Arsov, Todor

    2011-05-13

    The molecular basis of Kufs disease is unknown, whereas a series of genes accounting for most of the childhood-onset forms of neuronal ceroid lipofuscinosis (NCL) have been identified. Diagnosis of Kufs disease is difficult because the characteristic lipopigment is largely confined to neurons and can require a brain biopsy or autopsy for final diagnosis. We mapped four families with Kufs disease for whom there was good evidence of autosomal-recessive inheritance and found two peaks on chromosome 15. Three of the families were affected by Kufs type A disease and presented with progressive myoclonus epilepsy, and one was affected by type B (presenting with dementia and motor system dysfunction). Sequencing of a candidate gene in one peak shared by all four families identified no mutations, but sequencing of CLN6, found in the second peak and shared by only the three families affected by Kufs type A disease, revealed pathogenic mutations in all three families. We subsequently sequenced CLN6 in eight other families, three of which were affected by recessive Kufs type A disease. Mutations in both CLN6 alleles were found in the three type A cases and in one family affected by unclassified Kufs disease. Mutations in CLN6 are the major cause of recessive Kufs type A disease. The phenotypic differences between variant late-infantile NCL, previously found to be caused by CLN6, and Kufs type A disease are striking; there is a much later age at onset and lack of visual involvement in the latter. Sequencing of CLN6 will provide a simple diagnostic strategy in this disorder, in which definitive identification usually requires invasive biopsy.

  12. Mutations in a TGF-β ligand, TGFB3, cause syndromic aortic aneurysms and dissections.

    Science.gov (United States)

    Bertoli-Avella, Aida M; Gillis, Elisabeth; Morisaki, Hiroko; Verhagen, Judith M A; de Graaf, Bianca M; van de Beek, Gerarda; Gallo, Elena; Kruithof, Boudewijn P T; Venselaar, Hanka; Myers, Loretha A; Laga, Steven; Doyle, Alexander J; Oswald, Gretchen; van Cappellen, Gert W A; Yamanaka, Itaru; van der Helm, Robert M; Beverloo, Berna; de Klein, Annelies; Pardo, Luba; Lammens, Martin; Evers, Christina; Devriendt, Koenraad; Dumoulein, Michiel; Timmermans, Janneke; Bruggenwirth, Hennie T; Verheijen, Frans; Rodrigus, Inez; Baynam, Gareth; Kempers, Marlies; Saenen, Johan; Van Craenenbroeck, Emeline M; Minatoya, Kenji; Matsukawa, Ritsu; Tsukube, Takuro; Kubo, Noriaki; Hofstra, Robert; Goumans, Marie Jose; Bekkers, Jos A; Roos-Hesselink, Jolien W; van de Laar, Ingrid M B H; Dietz, Harry C; Van Laer, Lut; Morisaki, Takayuki; Wessels, Marja W; Loeys, Bart L

    2015-04-07

    Aneurysms affecting the aorta are a common condition associated with high mortality as a result of aortic dissection or rupture. Investigations of the pathogenic mechanisms involved in syndromic types of thoracic aortic aneurysms, such as Marfan and Loeys-Dietz syndromes, have revealed an important contribution of disturbed transforming growth factor (TGF)-β signaling. This study sought to discover a novel gene causing syndromic aortic aneurysms in order to unravel the underlying pathogenesis. We combined genome-wide linkage analysis, exome sequencing, and candidate gene Sanger sequencing in a total of 470 index cases with thoracic aortic aneurysms. Extensive cardiological examination, including physical examination, electrocardiography, and transthoracic echocardiography was performed. In adults, imaging of the entire aorta using computed tomography or magnetic resonance imaging was done. Here, we report on 43 patients from 11 families with syndromic presentations of aortic aneurysms caused by TGFB3 mutations. We demonstrate that TGFB3 mutations are associated with significant cardiovascular involvement, including thoracic/abdominal aortic aneurysm and dissection, and mitral valve disease. Other systemic features overlap clinically with Loeys-Dietz, Shprintzen-Goldberg, and Marfan syndromes, including cleft palate, bifid uvula, skeletal overgrowth, cervical spine instability and clubfoot deformity. In line with previous observations in aortic wall tissues of patients with mutations in effectors of TGF-β signaling (TGFBR1/2, SMAD3, and TGFB2), we confirm a paradoxical up-regulation of both canonical and noncanonical TGF-β signaling in association with up-regulation of the expression of TGF-β ligands. Our findings emphasize the broad clinical variability associated with TGFB3 mutations and highlight the importance of early recognition of the disease because of high cardiovascular risk. Copyright © 2015 American College of Cardiology Foundation. Published by

  13. Mutations in G-protein coupled receptors and their ligands as the molecular cause of endocrine diseases: from mutation detection to structure-function relation-ships

    OpenAIRE

    Biebermann, Heike

    2010-01-01

    G protein coupled receptors (GPCR) are the largest family of integral membrane proteins. GPCR transmit the information of extracellular signal into the cell where they influence the activity of effector systems that in turn modulated the concentration of second messengers. Genetic variations in GPCR are the molecular cause of a variety of human diseases. Mutations could lead to inactivation of the receptors or to ligand-independent constitutive activation. Moreover mutations in ligands fo...

  14. Generalized arterial calcification of infancy and pseudoxanthoma elasticum can be caused by mutations in either ENPP1 or ABCC6

    NARCIS (Netherlands)

    Nitschke, Y.; Baujat, G.; Botschen, U.; Wittkampf, T.; du Moulin, M.; Stella, J.; Le Merrer, M.; Guest, G.; Lambot, K.; Tazarourte-Pinturier, M.F.; Chassaing, N.; Roche, O.; Feenstra, I.; Loechner, K.; Deshpande, C.; Garber, S.J.; Chikarmane, R.; Steinmann, B.; Shahinyan, T.; Martorell, L.; Davies, J.; Smith, W.E.; Kahler, S.G.; McCulloch, M.; Wraige, E.; Loidi, L.; Hohne, W.; Martin, L.; Hadj-Rabia, S.; Terkeltaub, R.; Rutsch, F.

    2012-01-01

    Spontaneous pathologic arterial calcifications in childhood can occur in generalized arterial calcification of infancy (GACI) or in pseudoxanthoma elasticum (PXE). GACI is associated with biallelic mutations in ENPP1 in the majority of cases, whereas mutations in ABCC6 are known to cause PXE.

  15. Disease-causing mutations in exon 11 of the medium-chain acyl-CoA dehydrogenase gene

    DEFF Research Database (Denmark)

    Andresen, B S; Jensen, T G; Bross, P

    1994-01-01

    spot. Here we describe the results from sequence analysis of exon 11 and part of the flanking introns from 36 compound heterozygous patients with MCAD deficiency. We have identified four previously unknown disease-causing mutations (M301T, S311R, R324X, and E359X) and two silent mutations in exon 11...

  16. Antisense Oligonucleotide (AON)-based Therapy for Leber Congenital Amaurosis Caused by a Frequent Mutation in CEP290

    NARCIS (Netherlands)

    Collin, R.W.J.; Hollander, A.I. den; Velde-Visser, S.D. van der; Bennicelli, J.; Bennett, J.; Cremers, F.P.M.

    2012-01-01

    Leber congenital amaurosis (LCA) is the most severe form of inherited retinal degeneration, with an onset in the first year of life. The most frequent mutation that causes LCA, present in at least 10% of individuals with LCA from North-American and Northern-European descent, is an intronic mutation

  17. Stickler syndrome caused by COL2A1 mutations: genotype-phenotype correlation in a series of 100 patients

    DEFF Research Database (Denmark)

    Hoornaert, Kristien P; Vereecke, Inge; Dewinter, Chantal

    2010-01-01

    Stickler syndrome is an autosomal dominant connective tissue disorder caused by mutations in different collagen genes. The aim of our study was to define more precisely the phenotype and genotype of Stickler syndrome type 1 by investigating a large series of patients with a heterozygous mutation...

  18. Mutations in two nonhomologous genes in a head-to-head configuration cause Ellis-van Creveld syndrome.

    NARCIS (Netherlands)

    Ruiz-Perez, V.L.; Tompson, S.W.; Blair, H.J.; Espinoza-Valdez, C.; Lapunzina, P.; Silva, E.O.; Hamel, B.C.J.; Gibbs, J.L.; Young, I.D.; Wright, M.J.; Goodship, J.A.

    2003-01-01

    Ellis-van Creveld syndrome (EvC) is an autosomal recessive skeletal dysplasia. Elsewhere, we described mutations in EVC in patients with this condition (Ruiz-Perez et al. 2000). We now report that mutations in EVC2 also cause EvC. These two genes lie in a head-to-head configuration that is conserved

  19. Stickler syndrome caused by COL2A1 mutations: genotype-phenotype correlation in a series of 100 patients

    DEFF Research Database (Denmark)

    Hoornaert, Kristien P; Vereecke, Inge; Dewinter, Chantal

    2010-01-01

    Stickler syndrome is an autosomal dominant connective tissue disorder caused by mutations in different collagen genes. The aim of our study was to define more precisely the phenotype and genotype of Stickler syndrome type 1 by investigating a large series of patients with a heterozygous mutation ...

  20. Phenotypic variability in a family with capillary malformations caused by a mutation in the RASA1 gene

    NARCIS (Netherlands)

    de Wijn, Robert S.; Oduber, Charlène E. U.; Breugem, Corstiaan C.; Alders, Marielle; Hennekam, Raoul C. M.; van der Horst, Chantal M. A. M.

    2012-01-01

    Hereditary capillary malformations are known to be caused by mutations in the RASA1 gene. The associated phenotype is still subject of debate. The purpose of this study was to conduct a RASA1 mutation analysis in the family that led to the initial discovery of the 5q locus, and to delineate the

  1. De novo CCND2 mutations leading to stabilization of cyclin D2 cause megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome

    NARCIS (Netherlands)

    G.M. Mirzaa (Ghayda); D.A. Parry (David); N.K. Fry; K.A. Giamanco (Kristin); J.A. Schwartzentruber (Jeremy); M. Vanstone (Megan); C.V. Logan (Clare); N. Roberts (Nicola); C.A. Johnson (Colin); S. Singh (Shawn); S.S. Kholmanskikh (Stanislav); C. Adams (Carissa); R.D. Hodge (Rebecca); R.F. Hevner (Robert); D.T. Bonthron (David); K.P.J. Braun (Kees P.); L. Faivre (Laurence); J.-B. Riviere; C. St-Onge (Christina); K.W. Gripp (Karen); G.M.S. Mancini (Grazia); K. Pang (Ki); E. Sweeney (Elizabeth); H. van Esch (Hilde); N.E. Verbeek (Nienke); D. Wieczorek (Dagmar); M. Steinraths (Michelle); J. Majewski (Jacek); K.M. Boycott (Kym); D.T. Pilz (Daniela); M.E. Ross (M Elizabeth); W.B. Dobyns (William); E. Sheridan (Eamonn); J. Friedman; S. Michaud; F. Bernier (Francois); M. Brudno (M.); B. Fernandez (B.); A. Knoppers (Annelies); J. Samuels (Jonathan); S.W. Scherer (Stephen)

    2014-01-01

    textabstractActivating mutations in genes encoding phosphatidylinositol 3-kinase (PI3K)-AKT pathway components cause megalencephaly-polymicrogyria-polydactyly- hydrocephalus syndrome (MPPH, OMIM 603387). Here we report that individuals with MPPH lacking upstream PI3K-AKT pathway mutations carry de

  2. De novo heterozygous mutations in SMC3 cause a range of Cornelia de Lange syndrome-overlapping phenotypes

    DEFF Research Database (Denmark)

    Gil-Rodríguez, María Concepción; Deardorff, Matthew A; Ansari, Morad

    2015-01-01

    LS-like features caused by mutations in SMC3. Modeling of the mutation effects on protein structure suggests a dominant-negative effect on the multimeric cohesin complex. When compared with typical CdLS, many SMC3-associated phenotypes are also characterized by postnatal microcephaly but with a less distinctive...

  3. Mutations in Three Genes Encoding Proteins Involved in Hair Shaft Formation Cause Uncombable Hair Syndrome.

    Science.gov (United States)

    Ü Basmanav, F Buket; Cau, Laura; Tafazzoli, Aylar; Méchin, Marie-Claire; Wolf, Sabrina; Romano, Maria Teresa; Valentin, Frederic; Wiegmann, Henning; Huchenq, Anne; Kandil, Rima; Garcia Bartels, Natalie; Kilic, Arzu; George, Susannah; Ralser, Damian J; Bergner, Stefan; Ferguson, David J P; Oprisoreanu, Ana-Maria; Wehner, Maria; Thiele, Holger; Altmüller, Janine; Nürnberg, Peter; Swan, Daniel; Houniet, Darren; Büchner, Aline; Weibel, Lisa; Wagner, Nicola; Grimalt, Ramon; Bygum, Anette; Serre, Guy; Blume-Peytavi, Ulrike; Sprecher, Eli; Schoch, Susanne; Oji, Vinzenz; Hamm, Henning; Farrant, Paul; Simon, Michel; Betz, Regina C

    2016-12-01

    Uncombable hair syndrome (UHS), also known as "spun glass hair syndrome," "pili trianguli et canaliculi," or "cheveux incoiffables" is a rare anomaly of the hair shaft that occurs in children and improves with age. UHS is characterized by dry, frizzy, spangly, and often fair hair that is resistant to being combed flat. Until now, both simplex and familial UHS-affected case subjects with autosomal-dominant as well as -recessive inheritance have been reported. However, none of these case subjects were linked to a molecular genetic cause. Here, we report the identification of UHS-causative mutations located in the three genes PADI3 (peptidylarginine deiminase 3), TGM3 (transglutaminase 3), and TCHH (trichohyalin) in a total of 11 children. All of these individuals carry homozygous or compound heterozygous mutations in one of these three genes, indicating an autosomal-recessive inheritance pattern in the majority of UHS case subjects. The two enzymes PADI3 and TGM3, responsible for posttranslational protein modifications, and their target structural protein TCHH are all involved in hair shaft formation. Elucidation of the molecular outcomes of the disease-causing mutations by cell culture experiments and tridimensional protein models demonstrated clear differences in the structural organization and activity of mutant and wild-type proteins. Scanning electron microscopy observations revealed morphological alterations in hair coat of Padi3 knockout mice. All together, these findings elucidate the molecular genetic causes of UHS and shed light on its pathophysiology and hair physiology in general. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  4. Late-onset Zellweger spectrum disorder caused by PEX6 mutations mimicking X-linked adrenoleukodystrophy.

    Science.gov (United States)

    Tran, Christel; Hewson, Stacy; Steinberg, Steven J; Mercimek-Mahmutoglu, Saadet

    2014-08-01

    Zellweger spectrum disorder is an autosomal recessively inherited multisystem disorder caused by one of the 13 different PEX gene defects resulting in defective peroxisomal assembly and multiple peroxisomal enzyme deficiencies. We report a new patient with late-onset Zellweger spectrum disorder mimicking X-linked adrenoleukodystrophy. This 8.5-year-old boy with normal development until 6.5 years of age presented with bilateral sensorineural hearing loss during a school hearing test. He then developed acute-onset diplopia, clumsiness, and cognitive dysfunction at age 7 years. Magnetic resonance imaging of the brain revealed symmetric leukodystrophy, although without gadolinium enhancement. Elevated plasma very long chain fatty acid levels were suggestive of X-linked adrenoleukodystrophy, but his ABCD1 gene had normal coding sequence and dosage. Additional studies of cultured skin fibroblasts were consistent with Zellweger spectrum disorder. Molecular testing identified disease-causing compound heterozygous mutations in the PEX6 gene supporting the Zellweger spectrum disorder diagnosis in this patient. We describe a new patient with late-onset Zellweger spectrum disorder caused by PEX6 mutations who presented with an acute neurodegenerative disease course mimicking X-linked adrenoleukodystrophy. This finding provides an additional reason that molecular confirmation is important for the genetic counseling and management of patients with a clinical and biochemical diagnosis of X-linked adrenoleukodystrophy. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Phenotypic Variability of Osteogenesis Imperfecta Type V Caused by an IFITM5 Mutation

    Science.gov (United States)

    Shapiro, Jay R; Lietman, Caressa; Grover, Monica; Lu, James T; Nagamani, Sandesh CS; Dawson, Brian C; Baldridge, Dustin M; Bainbridge, Matthew N; Cohn, Dan H; Blazo, Maria; Roberts, Timothy T; Brennen, Feng-Shu; Wu, Yimei; Gibbs, Richard A; Melvin, Pamela; Campeau, Philippe M; Lee, Brendan H

    2013-01-01

    In a large cohort of osteogenesis imperfecta type V (OI type V) patients (17 individuals from 12 families), we identified the same mutation in the 5′ untranslated region (5′UTR) of the interferon-induced transmembrane protein 5 (IFITM5) gene by whole exome and Sanger sequencing (IFITM5 c.–14C > T) and provide a detailed description of their phenotype. This mutation leads to the creation of a novel start codon adding five residues to IFITM5 and was recently reported in several other OI type V families. The variability of the phenotype was quite large even within families. Whereas some patients presented with the typical calcification of the forearm interosseous membrane, radial head dislocation and hyperplastic callus (HPC) formation following fractures, others had only some of the typical OI type V findings. Thirteen had calcification of interosseous membranes, 14 had radial head dislocations, 10 had HPC, 9 had long bone bowing, 11 could ambulate without assistance, and 1 had mild unilateral mixed hearing loss. The bone mineral density varied greatly, even within families. Our study thus highlights the phenotypic variability of OI type V caused by the IFITM5 mutation. PMID:23408678

  6. Isolated cardiomyopathy caused by a DMD nonsense mutation in somatic mosaicism: genetic normalization in skeletal muscle.

    Science.gov (United States)

    Juan-Mateu, J; Paradas, C; Olivé, M; Verdura, E; Rivas, E; González-Quereda, L; Rodríguez, M J; Baiget, M; Gallano, P

    2012-12-01

    X-linked dilated cardiomyopathy is a pure cardiac dystrophinopathy phenotype mainly caused by DMD mutations that present a specific transcription effect in cardiac tissue. We report a 26-year-old male who presented with severe dilated cardiomyopathy and high creatine kinase. The patient did not complain of skeletal muscle weakness. A muscle biopsy showed mild dystrophic changes and a low proportion of dystrophin-negative fibres. A molecular study identified a nonsense DMD mutation (p.Arg2098X) in somatic mosaicism. The ratio of mutant versus normal allele in blood and skeletal muscle suggests selective pressure against mutant muscle cells, a process known as genetic normalization. We hypothesize that this process may have mitigated skeletal muscle symptoms in this patient. This is the second report of a DMD somatic mosaic with evidence of genetic normalization in muscle. Somatic DMD mutations should be considered in patients presenting with idiopathic dilated cardiomyopathy. © 2011 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  7. De novo mutations of KIAA2022 in females cause intellectual disability and intractable epilepsy

    Science.gov (United States)

    de Lange, Iris M; Helbig, Katherine L; Weckhuysen, Sarah; Møller, Rikke S; Velinov, Milen; Dolzhanskaya, Natalia; Marsh, Eric; Helbig, Ingo; Devinsky, Orrin; Tang, Sha; Mefford, Heather C; Myers, Candace T; van Paesschen, Wim; Striano, Pasquale; van Gassen, Koen; van Kempen, Marjan; de Kovel, Carolien G F; Piard, Juliette; Minassian, Berge A; Nezarati, Marjan M; Pessoa, André; Jacquette, Aurelia; Maher, Bridget; Balestrini, Simona; Sisodiya, Sanjay; Warde, Marie Therese Abi; De St Martin, Anne; Chelly, Jamel; van ‘t Slot, Ruben; Van Maldergem, Lionel; Brilstra, Eva H; Koeleman, Bobby P C

    2016-01-01

    Background Mutations in the KIAA2022 gene have been reported in male patients with X-linked intellectual disability, and related female carriers were unaffected. Here, we report 14 female patients who carry a heterozygous de novo KIAA2022 mutation and share a phenotype characterised by intellectual disability and epilepsy. Methods Reported females were selected for genetic testing because of substantial developmental problems and/or epilepsy. X-inactivation and expression studies were performed when possible. Results All mutations were predicted to result in a frameshift or premature stop. 12 out of 14 patients had intractable epilepsy with myoclonic and/or absence seizures, and generalised in 11. Thirteen patients had mild to severe intellectual disability. This female phenotype partially overlaps with the reported male phenotype which consists of more severe intellectual disability, microcephaly, growth retardation, facial dysmorphisms and, less frequently, epilepsy. One female patient showed completely skewed X-inactivation, complete absence of RNA expression in blood and a phenotype similar to male patients. In the six other tested patients, X-inactivation was random, confirmed by a non-significant twofold to threefold decrease of RNA expression in blood, consistent with the expected mosaicism between cells expressing mutant or normal KIAA2022 alleles. Conclusions Heterozygous loss of KIAA2022 expression is a cause of intellectual disability in females. Compared with its hemizygous male counterpart, the heterozygous female disease has less severe intellectual disability, but is more often associated with a severe and intractable myoclonic epilepsy. PMID:27358180

  8. Hydrocephalus due to multiple ependymal malformations is caused by mutations in the MPDZ gene.

    Science.gov (United States)

    Saugier-Veber, Pascale; Marguet, Florent; Lecoquierre, François; Adle-Biassette, Homa; Guimiot, Fabien; Cipriani, Sara; Patrier, Sophie; Brasseur-Daudruy, Marie; Goldenberg, Alice; Layet, Valérie; Capri, Yline; Gérard, Marion; Frébourg, Thierry; Laquerrière, Annie

    2017-05-01

    Congenital hydrocephalus is considered as either acquired due to haemorrhage, infection or neoplasia or as of developmental nature and is divided into two subgroups, communicating and obstructive. Congenital hydrocephalus is either syndromic or non-syndromic, and in the latter no cause is found in more than half of the patients. In patients with isolated hydrocephalus, L1CAM mutations represent the most common aetiology. More recently, a founder mutation has also been reported in the MPDZ gene in foetuses presenting massive hydrocephalus, but the neuropathology remains unknown. We describe here three novel homozygous null mutations in the MPDZ gene in foetuses whose post-mortem examination has revealed a homogeneous phenotype characterized by multiple ependymal malformations along the aqueduct of Sylvius, the third and fourth ventricles as well as the central canal of the medulla, consisting in multifocal rosettes with immature cell accumulation in the vicinity of ependymal lining early detached from the ventricular zone. MPDZ also named MUPP1 is an essential component of tight junctions which are expressed from early brain development in the choroid plexuses and ependyma. Alterations in the formation of tight junctions within the ependyma very likely account for the lesions observed and highlight for the first time that primary multifocal ependymal malformations of the ventricular system is genetically determined in humans. Therefore, MPDZ sequencing should be performed when neuropathological examination reveals multifocal ependymal rosette formation within the aqueduct of Sylvius, of the third and fourth ventricles and of the central canal of the medulla.

  9. A novel mutation causing mild, atypical fumarylacetoacetase deficiency (Tyrosinemia type I: a case report

    Directory of Open Access Journals (Sweden)

    Kvittingen Eli-Anne

    2009-12-01

    Full Text Available Abstract A male patient, born to unrelated Belgian parents, presented at 4 months with epistaxis, haematemesis and haematochezia. On physical examination he presented petechiae and haematomas, and a slightly enlarged liver. Serum transaminases were elevated to 5-10 times upper limit of normal, alkaline phosphatases were 1685 U/L (180 s ( Fumarylacetoacetase (FAH protein and activity in cultured fibroblasts and liver tissue were decreased but not absent. 4-hydroxyphenylpyruvate dioxygenase activity in liver was normal, which is atypical for tyrosinemia type I. A novel mutation was found in the FAH gene: c.103G>A (Ala35Thr. In vitro expression studies showed this mutation results in a strongly decreased FAH protein expression. Dietary treatment with phenylalanine and tyrosine restriction was initiated at 4 months, leading to complete clinical and biochemical normalisation. The patient, currently aged 12 years, shows a normal physical and psychomotor development. This is the first report of mild tyrosinemia type I disease caused by an Ala35Thr mutation in the FAH gene, presenting atypically without increase of the diagnostically important toxic metabolites succinylacetone and succinylacetoacetate.

  10. Novel TCAP mutation c.32C>A causing limb girdle muscular dystrophy 2G.

    Directory of Open Access Journals (Sweden)

    Amirtharaj Francis

    Full Text Available TCAP encoded telethonin is a 19 kDa protein, which plays an important role in anchoring titin in Z disc of the sarcomere, and is known to cause LGMD2G, a rare muscle disorder characterised by proximal and distal lower limb weakness, calf hypertrophy and loss of ambulation. A total of 300 individuals with ARLGMD were recruited for this study. Among these we identified 8 clinically well characterised LGMD2G cases from 7 unrelated Dravidian families. Clinical examination revealed predominantly proximo-distal form of weakness, scapular winging, muscle atrophy, calf hypertrophy and foot drop, immunoblot showed either complete absence or severe reduction of telethonin. Genetic analysis revealed a novel nonsense homozygous mutation c.32C>A, p.(Ser11* in three patients of a consanguineous family and an 8 bp homozygous duplication c.26_33dupAGGTGTCG, p.(Arg12fs31* in another patient. Both mutations possibly lead to truncated protein or nonsense mediated decay. We could not find any functionally significant TCAP mutation in the remaining 6 samples, except for two other polymorphisms, c.453A>C, p.( =  and c.-178G>T, which were found in cases and controls. This is the first report from India to demonstrate TCAP association with LGMD2G.

  11. Mouse H6 Homeobox 1 (Hmx1 mutations cause cranial abnormalities and reduced body mass

    Directory of Open Access Journals (Sweden)

    Munroe Robert J

    2009-04-01

    involvement. Additionally, these mutant Hmx1 alleles represent the first mouse models of a recently-discovered Oculo-Auricular syndrome caused by mutation of the orthologous human gene.

  12. Mouse H6 Homeobox 1 (Hmx1) mutations cause cranial abnormalities and reduced body mass

    Science.gov (United States)

    Munroe, Robert J; Prabhu, Vinay; Acland, Greg M; Johnson, Kenneth R; Harris, Belinda S; O'Brien, Tim P; Welsh, Ian C; Noden, Drew M; Schimenti, John C

    2009-01-01

    , these mutant Hmx1 alleles represent the first mouse models of a recently-discovered Oculo-Auricular syndrome caused by mutation of the orthologous human gene. PMID:19379485

  13. Mouse H6 Homeobox 1 (Hmx1) mutations cause cranial abnormalities and reduced body mass.

    Science.gov (United States)

    Munroe, Robert J; Prabhu, Vinay; Acland, Greg M; Johnson, Kenneth R; Harris, Belinda S; O'Brien, Tim P; Welsh, Ian C; Noden, Drew M; Schimenti, John C

    2009-04-20

    represent the first mouse models of a recently-discovered Oculo-Auricular syndrome caused by mutation of the orthologous human gene.

  14. Mutations in GALC cause late-onset Krabbe disease with predominant cerebellar ataxia.

    Science.gov (United States)

    Shao, Yi-Hong; Choquet, Karine; La Piana, Roberta; Tétreault, Martine; Dicaire, Marie-Josée; Boycott, Kym M; Majewski, Jacek; Brais, Bernard

    2016-04-01

    Mutations in GALC cause Krabbe disease. This autosomal recessive leukodystrophy generally presents in early infancy as a severe disorder, but sometimes manifests as a milder adult-onset disease with spastic paraplegia as the main symptom. We recruited a family with five affected individuals presenting with adult-onset predominant cerebellar ataxia with mild spasticity. Whole exome sequencing (WES) revealed one novel and one previously reported compound heterozygous variants in GALC. Magnetic resonance imaging (MRI) confirmed the presence of typical Krabbe features. Our findings expand the phenotypic spectrum of adult-onset Krabbe disease and demonstrate the usefulness of combining WES and pattern-specific MRI for the diagnosis of neurodegenerative diseases.

  15. Mutations in c10orf11, a melanocyte-differentiation gene, cause autosomal-recessive albinism

    DEFF Research Database (Denmark)

    Grønskov, Karen; Dooley, Christopher M; Østergaard, Elsebet

    2013-01-01

    in an individual originating from Lithuania. Immunohistochemistry showed localization of C10orf11 in melanoblasts and melanocytes in human fetal tissue, but no localization was seen in retinal pigment epithelial cells. Knockdown of the zebrafish (Danio rerio) homolog with the use of morpholinos resulted...... in substantially decreased pigmentation and a reduction of the apparent number of pigmented melanocytes. The morphant phenotype was rescued by wild-type C10orf11, but not by mutant C10orf11. In conclusion, we have identified a melanocyte-differentiation gene, C10orf11, which when mutated causes autosomal...

  16. Mutations in the glucose-6-phosphatase gene that cause glycogen storage disease Type 1a

    Energy Technology Data Exchange (ETDEWEB)

    Lei, K.J.; Shelly, L.L.; Pan, C.J.; Sidbury, J.B.; Chou, J.Y. (National Institutes of Health, Bethesda, MD (United States))

    1993-10-22

    Glycogen storage disease (GSD) type 1a is caused by the deficiency of d-glucose-6-phosphatase (G6Pase), the key enzyme in glucose homeostasis. Despite both a high incidence and morbidity, the molecular mechanisms underlying this deficiency have eluded characterization. In the present study, the molecular and biochemical characterization of the human G6Pase complementary DNA, its gene, and the expressed protein, which is indistinguishable from human microsomal G6Pase are reported. Several mutations in the G6Pase gene of affected individuals that completely inactivate the enzyme have been identified. These results establish the molecular basis of this disease and open the way for future gene therapy.

  17. A Novel Homozygous Mutation in FOXC1 Causes Axenfeld Rieger Syndrome with Congenital Glaucoma.

    Directory of Open Access Journals (Sweden)

    Shazia Micheal

    Full Text Available Anterior segment dysgenesis (ASD disorders are a group of clinically and genetically heterogeneous phenotypes in which frequently cornea, iris, and lens are affected. This study aimed to identify novel mutations in PAX6, PITX2 and FOXC1 in families with anterior segment dysgenesis disorders.We studied 14 Pakistani and one Mexican family with Axenfeld Rieger syndrome (ARS; n = 10 or aniridia (n = 5. All affected and unaffected family members underwent full ophthalmologic and general examinations. Total genomic DNA was isolated from peripheral blood. PCR and Sanger sequencing were performed for the exons and intron-exon boundaries of the FOXC1, PAX6, and PITX2 genes.Mutations were identified in five of the 15 probands; four variants were novel and one variant was described previously. A novel de novo variant (c.225C>A; p.Tyr75* was identified in the PAX6 gene in two unrelated probands with aniridia. In addition, a known variant (c.649C>T; p.Arg217* in PAX6 segregated in a family with aniridia. In the FOXC1 gene, a novel heterozygous variant (c.454T>C; p.Trp152Arg segregated with the disease in a Mexican family with ARS. A novel homozygous variant (c.92_100del; p.Ala31_Ala33del in the FOXC1 gene segregated in a Pakistani family with ARS and congenital glaucoma.Our study expands the mutation spectrum of the PAX6 and FOXC1 genes in individuals with anterior segment dysgenesis disorders. In addition, our study suggests that FOXC1 mutations, besides typical autosomal dominant ARS, can also cause ARS with congenital glaucoma through an autosomal recessive inheritance pattern. Our results thus expand the disease spectrum of FOXC1, and may lead to a better understanding of the role of FOXC1 in development.

  18. A gain of function mutation in TNFRSF11B encoding osteoprotegerin causes osteoarthritis with chondrocalcinosis.

    Science.gov (United States)

    Ramos, Yolande F M; Bos, Steffan D; van der Breggen, Ruud; Kloppenburg, Margreet; Ye, Kai; Lameijer, Eric-Wubbo E M W; Nelissen, Rob G H H; Slagboom, P Eline; Meulenbelt, Ingrid

    2015-09-01

    To identify pathogenic mutations that reveal underlying biological mechanisms driving osteoarthritis (OA). Exome sequencing was applied to two distant family members with dominantly inherited early onset primary OA at multiple joint sites with chondrocalcinosis (familial generalised osteoarthritis, FOA). Confirmation of mutations occurred by genotyping and linkage analyses across the extended family. The functional effect of the mutation was investigated by means of a cell-based assay. To explore generalisability, mRNA expression analysis of the relevant genes in the discovered pathway was explored in preserved and osteoarthritic articular cartilage of independent patients undergoing joint replacement surgery. We identified a heterozygous, probably damaging, read-through mutation (c.1205A=>T; p.Stop402Leu) in TNFRSF11B encoding osteoprotegerin that is likely causal to the OA phenotype in the extended family. In a bone resorption assay, the mutant form of osteoprotegerin showed enhanced capacity to inhibit osteoclastogenesis and bone resorption. Expression analyses in preserved and affected articular cartilage of independent OA patients showed that upregulation of TNFRSF11B is a general phenomenon in the pathophysiological process. Albeit that the role of the molecular pathway of osteoprotegerin has been studied in OA, we are the first to demonstrate that enhanced osteoprotegerin function could be a directly underlying cause. We advocate that agents counteracting the function of osteoprotegerin could comply with new therapeutic interventions of OA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  19. Homozygous Mutations in WEE2 Cause Fertilization Failure and Female Infertility.

    Science.gov (United States)

    Sang, Qing; Li, Bin; Kuang, Yanping; Wang, Xueqian; Zhang, Zhihua; Chen, Biaobang; Wu, Ling; Lyu, Qifeng; Fu, Yonglun; Yan, Zheng; Mao, Xiaoyan; Xu, Yao; Mu, Jian; Li, Qiaoli; Jin, Li; He, Lin; Wang, Lei

    2018-04-05

    Fertilization is a fundamental process of development and is a prerequisite for successful human reproduction. In mice, although several receptor proteins have been shown to play important roles in the process of fertilization, only three genes have been shown to cause fertilization failure and infertility when deleted in vivo. In clinical practice, some infertility case subjects suffer from recurrent failure of in vitro fertilization and intracytoplasmic sperm injection attempts due to fertilization failure, but the genetic basis of fertilization failure in humans remains largely unknown. Wee2 is a key oocyte-specific kinase involved in the control of meiotic arrest in mice, but WEE2 has not been associated with any diseases in humans. In this study, we identified homozygous mutations in WEE2 that are responsible for fertilization failure in humans. All four independent affected individuals had homozygous loss-of-function missense mutations or homozygous frameshift protein-truncating mutations, and the phenotype of fertilization failure was shown to follow a Mendelian recessive inheritance pattern. All four mutations significantly decreased the amount of WEE2 protein in vitro and in affected individuals' oocytes in vivo, and they all led to abnormal serine phosphorylation of WEE2 and reduced tyrosine 15 phosphorylation of Cdc2 in vitro. In addition, injection of WEE2 cRNA into affected individuals' oocytes rescued the fertilization failure phenotype and led to the formation of blastocysts in vitro. This work presents a novel gene responsible for human fertilization failure and has implications for future therapeutic treatments for infertility cases. Copyright © 2018 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  20. Mutations in EXTL3 Cause Neuro-immuno-skeletal Dysplasia Syndrome.

    Science.gov (United States)

    Oud, Machteld M; Tuijnenburg, Paul; Hempel, Maja; van Vlies, Naomi; Ren, Zemin; Ferdinandusse, Sacha; Jansen, Machiel H; Santer, René; Johannsen, Jessika; Bacchelli, Chiara; Alders, Marielle; Li, Rui; Davies, Rosalind; Dupuis, Lucie; Cale, Catherine M; Wanders, Ronald J A; Pals, Steven T; Ocaka, Louise; James, Chela; Müller, Ingo; Lehmberg, Kai; Strom, Tim; Engels, Hartmut; Williams, Hywel J; Beales, Phil; Roepman, Ronald; Dias, Patricia; Brunner, Han G; Cobben, Jan-Maarten; Hall, Christine; Hartley, Taila; Le Quesne Stabej, Polona; Mendoza-Londono, Roberto; Davies, E Graham; de Sousa, Sérgio B; Lessel, Davor; Arts, Heleen H; Kuijpers, Taco W

    2017-02-02

    EXTL3 regulates the biosynthesis of heparan sulfate (HS), important for both skeletal development and hematopoiesis, through the formation of HS proteoglycans (HSPGs). By whole-exome sequencing, we identified homozygous missense mutations c.1382C>T, c.1537C>T, c.1970A>G, and c.2008T>G in EXTL3 in nine affected individuals from five unrelated families. Notably, we found the identical homozygous missense mutation c.1382C>T (p.Pro461Leu) in four affected individuals from two unrelated families. Affected individuals presented with variable skeletal abnormalities and neurodevelopmental defects. Severe combined immunodeficiency (SCID) with a complete absence of T cells was observed in three families. EXTL3 was most abundant in hematopoietic stem cells and early progenitor T cells, which is in line with a SCID phenotype at the level of early T cell development in the thymus. To provide further support for the hypothesis that mutations in EXTL3 cause a neuro-immuno-skeletal dysplasia syndrome, and to gain insight into the pathogenesis of the disorder, we analyzed the localization of EXTL3 in fibroblasts derived from affected individuals and determined glycosaminoglycan concentrations in these cells as well as in urine and blood. We observed abnormal glycosaminoglycan concentrations and increased concentrations of the non-sulfated chondroitin disaccharide D0a0 and the disaccharide D0a4 in serum and urine of all analyzed affected individuals. In summary, we show that biallelic mutations in EXTL3 disturb glycosaminoglycan synthesis and thus lead to a recognizable syndrome characterized by variable expression of skeletal, neurological, and immunological abnormalities. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  1. Waardenburg syndrome type 4: report of two new cases caused by SOX10 mutations in Spain.

    Science.gov (United States)

    Fernández, Raquel M; Núñez-Ramos, Raquel; Enguix-Riego, M Valle; Román-Rodríguez, Francisco José; Galán-Gómez, Enrique; Blesa-Sánchez, Emilio; Antiñolo, Guillermo; Núñez-Núñez, Ramón; Borrego, Salud

    2014-02-01

    Shah-Waardenburg syndrome or Waardenburg syndrome type 4 (WS4) is a neurocristopathy characterized by the association of deafness, depigmentation and Hirschsprung disease. Three disease-causing genes have been identified so far for WS4: EDNRB, EDN3, and SOX10. SOX10 mutations, found in 45-55% of WS4 patients, are inherited in autosomal dominant way. In addition, mutations in SOX10 are also responsible for an extended syndrome involving peripheral and central neurological phenotypes, referred to as PCWH (peripheral demyelinating neuropathy, central dysmyelinating leucodystrophy, Waardenburg syndrome, Hirschsprung disease). Such mutations are mostly private, and a high intra- and inter-familial variability exists. In this report, we present a patient with WS4 and a second with PCWH due to SOX10 mutations supporting again the genetic and phenotypic heterogeneity of these syndromes. Interestingly, the WS4 family carries an insertion of 19 nucleotides in exon 5 of SOX10, which results in distinct phenotypes along three different generations: hypopigmentation in the maternal grandmother, hearing loss in the mother, and WS4 in the proband. Since mosaicism cannot explain the three different related-WS features observed in this family, we propose as the most plausible explanation the existence of additional molecular events, acting in an additive or multiplicative fashion, in genes or regulatory regions unidentified so far. On the other hand, the PCWH case was due to a de novo deletion in exon 5 of the gene. Efforts should be devoted to unravel the mechanisms underlying the intrafamilial phenotypic variability observed in the families affected, and to identify new genes responsible for the still unsolved WS4 cases. © 2013 Wiley Periodicals, Inc.

  2. Identification of a disease-causing mutation in a Chinese patient with retinitis pigmentosa by targeted next-generation sequencing

    DEFF Research Database (Denmark)

    Xiao, Jianping; Guo, Xueqin; Wang, Yong

    2017-01-01

    disease-causing mutations. Sanger sequencing was performed on all subjects to confirm the candidate mutations and assess cosegregation within the family. Results: Clinical examinations of the proband showed typical characteristics of RP. Three candidate heterozygous mutations in 3 genes associated with RP...... were detected in the proband by targeted NGS. The 3 mutations were confirmed by Sanger sequencing and the deletion (c.357_358delAA) in PRPF31 was shown to cosegregate with RP phenotype in 7 affected family members, but not in 3 unaffected family members. Conclusions: The deletion (c.357_358del......Purpose: To identify disease-causing mutations in a Chinese patient with retinitis pigmentosa (RP). Methods: A detailed clinical examination was performed on the proband. Targeted next-generation sequencing (NGS) combined with bioinformatics analysis was performed on the proband to detect candidate...

  3. Loss-of-activity-mutation in the cardiac chloride-bicarbonate exchanger AE3 causes short QT syndrome

    DEFF Research Database (Denmark)

    Thorsen, Kasper; Dam, Vibeke S.; Kjaer-Sorensen, Kasper

    2017-01-01

    Patients with short QT syndrome (SQTS) may present with syncope, ventricular fibrillation or sudden cardiac death. Six SQTS susceptibility genes, encoding cation channels, explain ... unrelated families with SQTS. The mutation causes reduced surface expression of AE3 and reduced membrane bicarbonate transport. Slc4a3 knockdown in zebrafish causes increased cardiac pHi, short QTc, and reduced systolic duration, which is rescued by wildtype but not mutated SLC4A3. Mechanistic analyses...

  4. Novel association of neurofibromatosis type 1-causing mutations in families with neurofibromatosis-Noonan syndrome.

    Science.gov (United States)

    Ekvall, Sara; Sjörs, Kerstin; Jonzon, Anders; Vihinen, Mauno; Annerén, Göran; Bondeson, Marie-Louise

    2014-03-01

    Neurofibromatosis-Noonan syndrome (NFNS) is a rare condition with clinical features of both neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). All three syndromes belong to the RASopathies, which are caused by dysregulation of the RAS-MAPK pathway. The major gene involved in NFNS is NF1, but co-occurring NF1 and PTPN11 mutations in NFNS have been reported. Knowledge about possible involvement of additional RASopathy-associated genes in NFNS is, however, very limited. We present a comprehensive clinical and molecular analysis of eight affected individuals from three unrelated families displaying features of NF1 and NFNS. The genetic etiology of the clinical phenotypes was investigated by mutation analysis, including NF1, PTPN11, SOS1, KRAS, NRAS, BRAF, RAF1, SHOC2, SPRED1, MAP2K1, MAP2K2, and CBL. All three families harbored a heterozygous NF1 variant, where the first family had a missense variant, c.5425C>T;p.R1809C, the second family a recurrent 4bp-deletion, c.6789_6792delTTAC;p.Y2264Tfs*6, and the third family a splice-site variant, c.2991-1G>A, resulting in skipping of exon 18 and an in-frame deletion of 41 amino acids. These NF1 variants have all previously been reported in NF1 patients. Surprisingly, both c.6789_6792delTTAC and c.2991-1G>A are frequently associated with NF1, but association to NFNS has, to our knowledge, not previously been reported. Our results support the notion that NFNS represents a variant of NF1, genetically distinct from NS, and is caused by mutations in NF1, some of which also cause classical NF1. Due to phenotypic overlap between NFNS and NS, we propose screening for NF1 mutations in NS patients, preferentially when café-au-lait spots are present. © 2013 Wiley Periodicals, Inc.

  5. FAM20A mutations can cause enamel-renal syndrome (ERS.

    Directory of Open Access Journals (Sweden)

    Shih-Kai Wang

    Full Text Available Enamel-renal syndrome (ERS is an autosomal recessive disorder characterized by severe enamel hypoplasia, failed tooth eruption, intrapulpal calcifications, enlarged gingiva, and nephrocalcinosis. Recently, mutations in FAM20A were reported to cause amelogenesis imperfecta and gingival fibromatosis syndrome (AIGFS, which closely resembles ERS except for the renal calcifications. We characterized three families with AIGFS and identified, in each case, recessive FAM20A mutations: family 1 (c.992G>A; g.63853G>A; p.Gly331Asp, family 2 (c.720-2A>G; g.62232A>G; p.Gln241_Arg271del, and family 3 (c.406C>T; g.50213C>T; p.Arg136* and c.1432C>T; g.68284C>T; p.Arg478*. Significantly, a kidney ultrasound of the family 2 proband revealed nephrocalcinosis, revising the diagnosis from AIGFS to ERS. By characterizing teeth extracted from the family 3 proband, we demonstrated that FAM20A(-/- molars lacked true enamel, showed extensive crown and root resorption, hypercementosis, and partial replacement of resorbed mineral with bone or coalesced mineral spheres. Supported by the observation of severe ectopic calcifications in the kidneys of Fam20a null mice, we conclude that FAM20A, which has a kinase homology domain and localizes to the Golgi, is a putative Golgi kinase that plays a significant role in the regulation of biomineralization processes, and that mutations in FAM20A cause both AIGFS and ERS.

  6. FAM20A Mutations Can Cause Enamel-Renal Syndrome (ERS)

    Science.gov (United States)

    Wang, Shih-Kai; Aref, Parissa; Hu, Yuanyuan; Milkovich, Rachel N.; Simmer, James P.; El-Khateeb, Mohammad; Daggag, Hinda; Baqain, Zaid H.; Hu, Jan C-C.

    2013-01-01

    Enamel-renal syndrome (ERS) is an autosomal recessive disorder characterized by severe enamel hypoplasia, failed tooth eruption, intrapulpal calcifications, enlarged gingiva, and nephrocalcinosis. Recently, mutations in FAM20A were reported to cause amelogenesis imperfecta and gingival fibromatosis syndrome (AIGFS), which closely resembles ERS except for the renal calcifications. We characterized three families with AIGFS and identified, in each case, recessive FAM20A mutations: family 1 (c.992G>A; g.63853G>A; p.Gly331Asp), family 2 (c.720-2A>G; g.62232A>G; p.Gln241_Arg271del), and family 3 (c.406C>T; g.50213C>T; p.Arg136* and c.1432C>T; g.68284C>T; p.Arg478*). Significantly, a kidney ultrasound of the family 2 proband revealed nephrocalcinosis, revising the diagnosis from AIGFS to ERS. By characterizing teeth extracted from the family 3 proband, we demonstrated that FAM20A −/− molars lacked true enamel, showed extensive crown and root resorption, hypercementosis, and partial replacement of resorbed mineral with bone or coalesced mineral spheres. Supported by the observation of severe ectopic calcifications in the kidneys of Fam20a null mice, we conclude that FAM20A, which has a kinase homology domain and localizes to the Golgi, is a putative Golgi kinase that plays a significant role in the regulation of biomineralization processes, and that mutations in FAM20A cause both AIGFS and ERS. PMID:23468644

  7. A Founder Mutation in VPS11 Causes an Autosomal Recessive Leukoencephalopathy Linked to Autophagic Defects.

    Directory of Open Access Journals (Sweden)

    Jinglan Zhang

    2016-04-01

    Full Text Available Genetic leukoencephalopathies (gLEs are a group of heterogeneous disorders with white matter abnormalities affecting the central nervous system (CNS. The causative mutation in ~50% of gLEs is unknown. Using whole exome sequencing (WES, we identified homozygosity for a missense variant, VPS11: c.2536T>G (p.C846G, as the genetic cause of a leukoencephalopathy syndrome in five individuals from three unrelated Ashkenazi Jewish (AJ families. All five patients exhibited highly concordant disease progression characterized by infantile onset leukoencephalopathy with brain white matter abnormalities, severe motor impairment, cortical blindness, intellectual disability, and seizures. The carrier frequency of the VPS11: c.2536T>G variant is 1:250 in the AJ population (n = 2,026. VPS11 protein is a core component of HOPS (homotypic fusion and protein sorting and CORVET (class C core vacuole/endosome tethering protein complexes involved in membrane trafficking and fusion of the lysosomes and endosomes. The cysteine 846 resides in an evolutionarily conserved cysteine-rich RING-H2 domain in carboxyl terminal regions of VPS11 proteins. Our data shows that the C846G mutation causes aberrant ubiquitination and accelerated turnover of VPS11 protein as well as compromised VPS11-VPS18 complex assembly, suggesting a loss of function in the mutant protein. Reduced VPS11 expression leads to an impaired autophagic activity in human cells. Importantly, zebrafish harboring a vps11 mutation with truncated RING-H2 domain demonstrated a significant reduction in CNS myelination following extensive neuronal death in the hindbrain and midbrain. Thus, our study reveals a defect in VPS11 as the underlying etiology for an autosomal recessive leukoencephalopathy disorder associated with a dysfunctional autophagy-lysosome trafficking pathway.

  8. MKS1 mutations cause Joubert syndrome with agenesis of the corpus callosum.

    Science.gov (United States)

    Bader, Ingrid; Decker, E; Mayr, J A; Lunzer, V; Koch, J; Boltshauser, E; Sperl, W; Pietsch, P; Ertl-Wagner, B; Bolz, H; Bergmann, C; Rittinger, O

    2016-08-01

    Joubert syndrome (JS) is a clinically and genetically heterogeneous ciliopathy characterized by episodic hyperpnea and apnea, hypotonia, ataxia, cognitive impairment and ocular motor apraxia. The "molar tooth sign" is pathognomonic of this condition. Mutations in the MKS1 gene are a major cause of Meckel-Gruber syndrome (MKS), the most common form of syndromic neural tube defects, frequently resulting in perinatal lethality. We present the phenotype and genotype of a child with severe JS and agenesis of the corpus callosum (ACC). In our patient, a next generation sequencing (NGS) approach revealed the following two variants of the MKS1 gene: first, a novel missense variant [ c.240G > T (p.Trp80Cys)], which affects a residue that is evolutionarily highly conserved in mammals and ciliates; second, a 29 bp deletion in intron 15 [c.1408-35_1408-7del29], a founder mutation, which in a homozygous state constitutes the major cause of MKS in Finland. We review the MKS1-variants in all of the eleven JS patients reported to date and compare these patients to our case. To our knowledge, this is the first patient with Joubert syndrome and agenesis of the corpus callosum where a potentially causal genotype is provided. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Parotid Sebaceous Carcinoma in Patient with Muir Torre Syndrome, Caused by MSH2 Mutation.

    Science.gov (United States)

    Neelakantan, Iyer Vishwas; Di Palma, Silvana; Smith, C E T; McCoombe, A

    2016-09-01

    Sebaceous carcinoma of parotid gland are extremely rare with only 29 cases reported so far. The development of parotid sebaceous carcinoma in association with mutation in the mismatch repair gene that causes Muir Torre Syndrome (MTS), a subset of Lynch Syndrome, is still unclear. This study describes such a case and reviews the literature to see if an association between parotid sebaceous carcinoma and multiple visceral malignancies seen in Lynch Syndrome has ever been described. MTS represents a small subset of the Hereditary Non Polyposis Colorectal Carcinoma family, thought to be a subtype of Lynch Syndrome, where patients are prone to develop multiple visceral cancers involving gastrointestinal and genitourinary tract along with sebaceous and non-sebaceous tumours of the skin. MTS is a rare hereditary, autosomal dominant cancer syndrome caused by Microsatellite Instability and defect in DNA mismatch repair protein. The germline mutation involves mostly hMSH2 and hMLH1 genes. In MTS the skin of the head and neck area with the periocular region in particular, is affected but sebaceous carcinomas of the parotid associated with visceral malignancies has not yet been reported in literature. Here we report an index case of sebaceous carcinoma of parotid gland in a patient with MTS.

  10. X-linked agammaglobulinemia caused by new mutation in BTK gene: a case report.

    Science.gov (United States)

    Havlicekova, Zuzana; Jesenak, Milos; Freiberger, Tomas; Banovcin, Peter

    2014-09-01

    Primary immunodeficiencies (PID) are becoming a recognized public health problem worldwide. The most important subgroup of these disorders are the antibody deficiencies. X-linked agammaglobulinaemia was the first described entity of this group and is characterised by early onset of recurrent bacterial infections, profound deficiency of all immunoglobulin isotypes and markedly reduced number of peripheral B-lymphocytes. We report the case of a 10-year old boy with X-linked agammaglobulinaemia caused by a previously non-described mutation in BTK gene with typical clinical presentation but delayed diagnosis. Following diagnosis, substitution therapy with intravenous immunoglobulins was started and the clinical status of the patient improved. We reported a case of X-linked agammaglobulinaemia with delayed diagnosis despite the typical anamnestic signs for primary humoral immunodeficiency. The disease was caused by a previously non-reported mutation in the BTK gene. Measurement of serum immunoglobulins should be performed in all children with recurrent, complicated respiratory infections as a screening test for humoral immunodeficiencies.

  11. Two missense mutations in KCNQ1 cause pituitary hormone deficiency and maternally inherited gingival fibromatosis.

    Science.gov (United States)

    Tommiska, Johanna; Känsäkoski, Johanna; Skibsbye, Lasse; Vaaralahti, Kirsi; Liu, Xiaonan; Lodge, Emily J; Tang, Chuyi; Yuan, Lei; Fagerholm, Rainer; Kanters, Jørgen K; Lahermo, Päivi; Kaunisto, Mari; Keski-Filppula, Riikka; Vuoristo, Sanna; Pulli, Kristiina; Ebeling, Tapani; Valanne, Leena; Sankila, Eeva-Marja; Kivirikko, Sirpa; Lääperi, Mitja; Casoni, Filippo; Giacobini, Paolo; Phan-Hug, Franziska; Buki, Tal; Tena-Sempere, Manuel; Pitteloud, Nelly; Veijola, Riitta; Lipsanen-Nyman, Marita; Kaunisto, Kari; Mollard, Patrice; Andoniadou, Cynthia L; Hirsch, Joel A; Varjosalo, Markku; Jespersen, Thomas; Raivio, Taneli

    2017-11-03

    Familial growth hormone deficiency provides an opportunity to identify new genetic causes of short stature. Here we combine linkage analysis with whole-genome resequencing in patients with growth hormone deficiency and maternally inherited gingival fibromatosis. We report that patients from three unrelated families harbor either of two missense mutations, c.347G>T p.(Arg116Leu) or c.1106C>T p.(Pro369Leu), in KCNQ1, a gene previously implicated in the long QT interval syndrome. Kcnq1 is expressed in hypothalamic GHRH neurons and pituitary somatotropes. Co-expressing KCNQ1 with the KCNE2 β-subunit shows that both KCNQ1 mutants increase current levels in patch clamp analyses and are associated with reduced pituitary hormone secretion from AtT-20 cells. In conclusion, our results reveal a role for the KCNQ1 potassium channel in the regulation of human growth, and show that growth hormone deficiency associated with maternally inherited gingival fibromatosis is an allelic disorder with cardiac arrhythmia syndromes caused by KCNQ1 mutations.

  12. ARCN1 Mutations Cause a Recognizable Craniofacial Syndrome Due to COPI-Mediated Transport Defects.

    Science.gov (United States)

    Izumi, Kosuke; Brett, Maggie; Nishi, Eriko; Drunat, Séverine; Tan, Ee-Shien; Fujiki, Katsunori; Lebon, Sophie; Cham, Breana; Masuda, Koji; Arakawa, Michiko; Jacquinet, Adeline; Yamazumi, Yusuke; Chen, Shu-Ting; Verloes, Alain; Okada, Yuki; Katou, Yuki; Nakamura, Tomohiko; Akiyama, Tetsu; Gressens, Pierre; Foo, Roger; Passemard, Sandrine; Tan, Ene-Choo; El Ghouzzi, Vincent; Shirahige, Katsuhiko

    2016-08-04

    Cellular homeostasis is maintained by the highly organized cooperation of intracellular trafficking systems, including COPI, COPII, and clathrin complexes. COPI is a coatomer protein complex responsible for intracellular protein transport between the endoplasmic reticulum and the Golgi apparatus. The importance of such intracellular transport mechanisms is underscored by the various disorders, including skeletal disorders such as cranio-lenticulo-sutural dysplasia and osteogenesis imperfect, caused by mutations in the COPII coatomer complex. In this article, we report a clinically recognizable craniofacial disorder characterized by facial dysmorphisms, severe micrognathia, rhizomelic shortening, microcephalic dwarfism, and mild developmental delay due to loss-of-function heterozygous mutations in ARCN1, which encodes the coatomer subunit delta of COPI. ARCN1 mutant cell lines were revealed to have endoplasmic reticulum stress, suggesting the involvement of ER stress response in the pathogenesis of this disorder. Given that ARCN1 deficiency causes defective type I collagen transport, reduction of collagen secretion represents the likely mechanism underlying the skeletal phenotype that characterizes this condition. Our findings demonstrate the importance of COPI-mediated transport in human development, including skeletogenesis and brain growth. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  13. How do Mutations in GJB1 Cause X-linked Charcot-Marie-Tooth Disease?

    Science.gov (United States)

    Kleopa, Kleopas A.; Abrams, Charles K.; Scherer, Steven S.

    2012-01-01

    The X-linked form of Charcot-Marie-Tooth disease (CMT1X) is the second most common form of hereditary motor and sensory neuropathy. The clinical phenotype is characterized by progressive weakness, atrophy, and sensory abnormalities that are most pronounced in the distal extremities. Some patients have CNS manifestations. Affected males have moderate to severe symptoms, whereas heterozygous females are usually less affected. Neurophysiology shows intermediate slowing of conduction and length-dependent axonal loss. Nerve biopsies show more prominent axonal degeneration than de/remyelination. Mutations in GJB1, the gene that encodes the gap junction (GJ) protein connexin32 (Cx32) cause CMT1X; more than 400 different mutations have been described. Many Cx32 mutants fail to form functional GJs, or form GJs with abnormal biophysical properties. Schwann cells and oligodendrocytes express Cx32, and the GJs formed by Cx32 play an important role in the homeostasis of myelinated axons. Animal models of CMT1X demonstrate that loss of Cx32 in myelinating Schwann cells causes a demyelinating neuropathy. Effective therapies remain to be developed. PMID:22771394

  14. Novel mutations causing biotinidase deficiency in individuals identified by newborn screening in Michigan including an unique intronic mutation that alters mRNA expression of the biotinidase gene.

    Science.gov (United States)

    Li, H; Spencer, L; Nahhas, F; Miller, J; Fribley, A; Feldman, G; Conway, R; Wolf, B

    2014-07-01

    Biotinidase deficiency (BD) is an autosomal recessive disorder resulting in the inability to recycle the vitamin biotin. Individuals with biotinidase deficiency can develop neurological and cutaneous symptoms if they are not treated with biotin. To date, more than 165 mutations in the biotinidase gene (BTD) have been reported. Essentially all the mutations result in enzymatic activities with less than 10% of mean normal serum enzyme activity (profound biotinidase deficiency) with the exception of the c.1330G>C (p.D444H) mutation, which results in an enzyme having 50% of mean normal serum activity and causes partial biotinidase deficiency (10-30% of mean normal serum biotinidase activity) if there is a mutation for profound biotinidase deficiency on the second allele. We now reported eight novel mutations in ten children identified by newborn screening in Michigan from 1988 to the end of 2012. Interestingly, one intronic mutation, c.310-15delT, results in an approximately two-fold down-regulation of BTD mRNA expression by Quantitative real-time reverse-transcription PCR (qRT-PCR). This is the first report of an intronic mutation in the BTD gene with demonstration of its effect on enzymatic activity by altering mRNA expression. This study identified three other mutations likely to cause partial biotinidase deficiency. These results emphasize the importance of full gene sequencing of BTD on patients with biotinidase deficiency to better understand the genotype and phenotype correlation in the future. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. A de novo missense mutation of FGFR2 causes facial dysplasia syndrome in Holstein cattle.

    Science.gov (United States)

    Agerholm, Jørgen S; McEvoy, Fintan J; Heegaard, Steffen; Charlier, Carole; Jagannathan, Vidhya; Drögemüller, Cord

    2017-08-02

    Surveillance for bovine genetic diseases in Denmark identified a hitherto unreported congenital syndrome occurring among progeny of a Holstein sire used for artificial breeding. A genetic aetiology due to a dominant inheritance with incomplete penetrance or a mosaic germline mutation was suspected as all recorded cases were progeny of the same sire. Detailed investigations were performed to characterize the syndrome and to reveal its cause. Seven malformed calves were submitted examination. All cases shared a common morphology with the most striking lesions being severe facial dysplasia and complete prolapse of the eyes. Consequently the syndrome was named facial dysplasia syndrome (FDS). Furthermore, extensive brain malformations, including microencephaly, hydrocephalus, lobation of the cerebral hemispheres and compression of the brain were present. Subsequent data analysis of progeny of the sire revealed that around 0.5% of his offspring suffered from FDS. High density single nucleotide polymorphism (SNP) genotyping data of the seven cases and their parents were used to map the defect in the bovine genome. Significant genetic linkage was obtained for three regions, including chromosome 26 where whole genome sequencing of a case-parent trio revealed two de novo variants perfectly associated with the disease: an intronic SNP in the DMBT1 gene and a single non-synonymous variant in the FGFR2 gene. This FGFR2 missense variant (c.927G>T) affects a gene encoding a member of the fibroblast growth factor receptor family, where amino acid sequence is highly conserved between members and across species. It is predicted to change an evolutionary conserved tryptophan into a cysteine residue (p.Trp309Cys). Both variant alleles were proven to result from de novo mutation events in the germline of the sire. FDS is a novel genetic disorder of Holstein cattle. Mutations in the human FGFR2 gene are associated with various dominant inherited craniofacial dysostosis syndromes. Given

  16. Heterozygous Germline Mutations in the CBL Tumor-Suppressor Gene Cause a Noonan Syndrome-like Phenotype

    Science.gov (United States)

    Martinelli, Simone; De Luca, Alessandro; Stellacci, Emilia; Rossi, Cesare; Checquolo, Saula; Lepri, Francesca; Caputo, Viviana; Silvano, Marianna; Buscherini, Francesco; Consoli, Federica; Ferrara, Grazia; Digilio, Maria C.; Cavaliere, Maria L.; van Hagen, Johanna M.; Zampino, Giuseppe; van der Burgt, Ineke; Ferrero, Giovanni B.; Mazzanti, Laura; Screpanti, Isabella; Yntema, Helger G.; Nillesen, Willy M.; Savarirayan, Ravi; Zenker, Martin; Dallapiccola, Bruno; Gelb, Bruce D.; Tartaglia, Marco

    2010-01-01

    RAS signaling plays a key role in controlling appropriate cell responses to extracellular stimuli and participates in early and late developmental processes. Although enhanced flow through this pathway has been established as a major contributor to oncogenesis, recent discoveries have revealed that aberrant RAS activation causes a group of clinically related developmental disorders characterized by facial dysmorphism, a wide spectrum of cardiac disease, reduced growth, variable cognitive deficits, ectodermal and musculoskeletal anomalies, and increased risk for certain malignancies. Here, we report that heterozygous germline mutations in CBL, a tumor-suppressor gene that is mutated in myeloid malignancies and encodes a multivalent adaptor protein with E3 ubiquitin ligase activity, can underlie a phenotype with clinical features fitting or partially overlapping Noonan syndrome (NS), the most common condition of this disease family. Independent CBL mutations were identified in two sporadic cases and two families from among 365 unrelated subjects who had NS or suggestive features and were negative for mutations in previously identified disease genes. Phenotypic heterogeneity and variable expressivity were documented. Mutations were missense changes altering evolutionarily conserved residues located in the RING finger domain or the linker connecting this domain to the N-terminal tyrosine kinase binding domain, a known mutational hot spot in myeloid malignancies. Mutations were shown to affect CBL-mediated receptor ubiquitylation and dysregulate signal flow through RAS. These findings document that germline mutations in CBL alter development to cause a clinically variable condition that resembles NS and that possibly predisposes to malignancies. PMID:20619386

  17. Exome Sequencing and Functional Validation in Zebrafish Identify GTDC2 Mutations as a Cause of Walker-Warburg Syndrome

    Science.gov (United States)

    Manzini, M. Chiara; Tambunan, Dimira E.; Hill, R. Sean; Yu, Tim W.; Maynard, Thomas M.; Heinzen, Erin L.; Shianna, Kevin V.; Stevens, Christine R.; Partlow, Jennifer N.; Barry, Brenda J.; Rodriguez, Jacqueline; Gupta, Vandana A.; Al-Qudah, Abdel-Karim; Eyaid, Wafaa M.; Friedman, Jan M.; Salih, Mustafa A.; Clark, Robin; Moroni, Isabella; Mora, Marina; Beggs, Alan H.; Gabriel, Stacey B.; Walsh, Christopher A.

    2012-01-01

    Whole-exome sequencing (WES), which analyzes the coding sequence of most annotated genes in the human genome, is an ideal approach to studying fully penetrant autosomal-recessive diseases, and it has been very powerful in identifying disease-causing mutations even when enrollment of affected individuals is limited by reduced survival. In this study, we combined WES with homozygosity analysis of consanguineous pedigrees, which are informative even when a single affected individual is available, to identify genetic mutations responsible for Walker-Warburg syndrome (WWS), a genetically heterogeneous autosomal-recessive disorder that severely affects the development of the brain, eyes, and muscle. Mutations in seven genes are known to cause WWS and explain 50%–60% of cases, but multiple additional genes are expected to be mutated because unexplained cases show suggestive linkage to diverse loci. Using WES in consanguineous WWS-affected families, we found multiple deleterious mutations in GTDC2 (also known as AGO61). GTDC2’s predicted role as an uncharacterized glycosyltransferase is consistent with the function of other genes that are known to be mutated in WWS and that are involved in the glycosylation of the transmembrane receptor dystroglycan. Therefore, to explore the role of GTDC2 loss of function during development, we used morpholino-mediated knockdown of its zebrafish ortholog, gtdc2. We found that gtdc2 knockdown in zebrafish replicates all WWS features (hydrocephalus, ocular defects, and muscular dystrophy), strongly suggesting that GTDC2 mutations cause WWS. PMID:22958903

  18. Mutations in the ABCA4 (ABCR) Gene Are the Major Cause of Autosomal Recessive Cone-Rod Dystrophy

    Science.gov (United States)

    Maugeri, Alessandra; Klevering, B. Jeroen; Rohrschneider, Klaus; Blankenagel, Anita; Brunner, Han G.; Deutman, August F.; Hoyng, Carel B.; Cremers, Frans P. M.

    2000-01-01

    The photoreceptor cell–specific ATP-binding cassette transporter gene (ABCA4; previously denoted “ABCR”) is mutated in most patients with autosomal recessive (AR) Stargardt disease (STGD1) or fundus flavimaculatus (FFM). In addition, a few cases with AR retinitis pigmentosa (RP) and AR cone-rod dystrophy (CRD) have been found to have ABCA4 mutations. To evaluate the importance of the ABCA4 gene as a cause of AR CRD, we selected 5 patients with AR CRD and 15 patients with isolated CRD, all from Germany and The Netherlands . Single-strand conformation–polymorphism analysis and sequencing revealed 19 ABCA4 mutations in 13 (65%) of 20 patients. In six patients, mutations were identified in both ABCA4 alleles; in seven patients, mutations were detected in one allele. One complex ABCA4 allele (L541P;A1038V) was found exclusively in German patients with CRD; one patient carried this complex allele homozygously, and five others were compound heterozygous. These findings suggest that mutations in the ABCA4 gene are the major cause of AR CRD. A primary role of the ABCA4 gene in STGD1/FFM and AR CRD, together with the gene's involvement in an as-yet-unknown proportion of cases with AR RP, strengthens the idea that mutations in the ABCA4 gene could be the most frequent cause of inherited retinal dystrophy in humans. PMID:10958761

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Specific point mutations in Lactobacillus casei ATCC 27139 cause a phenotype switch from Lac- to Lac+.

    Science.gov (United States)

    Tsai, Yu-Kuo; Chen, Hung-Wen; Lo, Ta-Chun; Lin, Thy-Hou

    2009-03-01

    Lactose metabolism is a changeable phenotype in strains of Lactobacillus casei. In this study, we found that L. casei ATCC 27139 was unable to utilize lactose. However, when exposed to lactose as the sole carbon source, spontaneous Lac(+) clones could be obtained. A gene cluster (lacTEGF-galKETRM) involved in the metabolism of lactose and galactose in L. casei ATCC 27139 (Lac(-)) and its Lac(+) revertant (designated strain R1) was sequenced and characterized. We found that only one nucleotide, located in the lacTEGF promoter (lacTp), of the two lac-gal gene clusters was different. The protein sequence identity between the lac-gal gene cluster and those reported previously for some L. casei (Lac(+)) strains was high; namely, 96-100 % identity was found and no premature stop codon was identified. A single point mutation located within the lacTp promoter region was also detected for each of the 41 other independently isolated Lac(+) revertants of L. casei ATCC 27139. The revertants could be divided into six classes based on the positions of the point mutations detected. Primer extension experiments conducted on transcription from lacTp revealed that the lacTp promoter of these six classes of Lac(+) revertants was functional, while that of L. casei ATCC 27139 was not. Northern blotting experiments further confirmed that the lacTEGF operon of strain R1 was induced by lactose but suppressed by glucose, whereas no blotting signal was ever detected for L. casei ATCC 27139. These results suggest that a single point mutation in the lacTp promoter was able to restore the transcription of a fully functional lacTEGF operon and cause a phenotype switch from Lac(-) to Lac(+) for L. casei ATCC 27139.

  1. Human CalDAG-GEFI gene (RASGRP2) mutation affects platelet function and causes severe bleeding.

    Science.gov (United States)

    Canault, Matthias; Ghalloussi, Dorsaf; Grosdidier, Charlotte; Guinier, Marie; Perret, Claire; Chelghoum, Nadjim; Germain, Marine; Raslova, Hana; Peiretti, Franck; Morange, Pierre E; Saut, Noemie; Pillois, Xavier; Nurden, Alan T; Cambien, François; Pierres, Anne; van den Berg, Timo K; Kuijpers, Taco W; Alessi, Marie-Christine; Tregouet, David-Alexandre

    2014-06-30

    The nature of an inherited platelet disorder was investigated in three siblings affected by severe bleeding. Using whole-exome sequencing, we identified the culprit mutation (cG742T) in the RAS guanyl-releasing protein-2 (RASGRP2) gene coding for calcium- and DAG-regulated guanine exchange factor-1 (CalDAG-GEFI). Platelets from individuals carrying the mutation present a reduced ability to activate Rap1 and to perform proper αIIbβ3 integrin inside-out signaling. Expression of CalDAG-GEFI mutant in HEK293T cells abolished Rap1 activation upon stimulation. Nevertheless, the PKC- and ADP-dependent pathways allow residual platelet activation in the absence of functional CalDAG-GEFI. The mutation impairs the platelet's ability to form thrombi under flow and spread normally as a consequence of reduced Rac1 GTP-binding. Functional deficiencies were confined to platelets and megakaryocytes with no leukocyte alteration. This contrasts with the phenotype seen in type III leukocyte adhesion deficiency caused by the absence of kindlin-3. Heterozygous did not suffer from bleeding and have normal platelet aggregation; however, their platelets mimicked homozygous ones by failing to undergo normal adhesion under flow and spreading. Rescue experiments on cultured patient megakaryocytes corrected the functional deficiency after transfection with wild-type RASGRP2. Remarkably, the presence of a single normal allele is sufficient to prevent bleeding, making CalDAG-GEFI a novel and potentially safe therapeutic target to prevent thrombosis. © 2014 Canault et al.

  2. Bestrophin gene mutations cause canine multifocal retinopathy: a novel animal model for best disease.

    Science.gov (United States)

    Guziewicz, Karina E; Zangerl, Barbara; Lindauer, Sarah J; Mullins, Robert F; Sandmeyer, Lynne S; Grahn, Bruce H; Stone, Edwin M; Acland, Gregory M; Aguirre, Gustavo D

    2007-05-01

    Canine multifocal retinopathy (cmr) is an autosomal recessive disorder of multiple dog breeds. The disease shares a number of clinical and pathologic similarities with Best macular dystrophy (BMD), and cmr is proposed as a new large animal model for Best disease. cmr was characterized by ophthalmoscopy and histopathology and compared with BMD-affected patients. BEST1 (alias VMD2), the bestrophin gene causally associated with BMD, was evaluated in the dog. Canine ortholog cDNA sequence was cloned and verified using RPE/choroid 5'- and 3'-RACE. Expression of the canine gene transcripts and protein was analyzed by Northern and Western blotting and immunocytochemistry. All exons and the flanking splice junctions were screened by direct sequencing. The clinical phenotype and pathology of cmr closely resemble lesions of BMD. Canine VMD2 spans 13.7 kb of genomic DNA on CFA18 and shows a high level of conservation among eukaryotes. The transcript is predominantly expressed in RPE/choroid and encodes bestrophin, a 580-amino acid protein of 66 kDa. Immunocytochemistry of normal canine retina demonstrated specific localization of protein to the RPE basolateral plasma membranes. Two disease-specific sequence alterations were identified in the canine VMD2 gene: a C(73)T stop mutation in cmr1 and a G(482)A missense mutation in cmr2. The authors propose these two spontaneous mutations in the canine VMD2 gene, which cause cmr, as the first naturally occurring animal model of BMD. Further development of the cmr models will permit elucidation of the complex molecular mechanism of these retinopathies and the development of potential therapies.

  3. Novel PAX3 mutations causing Waardenburg syndrome type 1 in Tunisian patients.

    Science.gov (United States)

    Trabelsi, Mediha; Nouira, Malek; Maazoul, Faouzi; Kraoua, Lilia; Meddeb, Rim; Ouertani, Ines; Chelly, Imen; Benoit, Valérie; Besbes, Ghazi; Mrad, Ridha

    2017-12-01

    Waardenburg syndrome (WS) is an auditory-pigmentary disease characterized by a clinical and genetic variability. WS is classified into four types depending on the presence or absence of additional symptoms: WS1, WS2, WS3 and WS4. Type 1 and 3 are mostly caused by PAX3 mutations, while type 2 and type 4 are genetically heterogeneous. The aims of this study are to confirm the diagnostic of WS1 by the sequencing of PAX3 gene and to evaluate the genotype phenotype correlation. A clinical classification was established for 14 patients WS, as proposed by the Waardenburg Consortium, and noted a predominance of type 1 and type 2 with 6 patients WS1, 7 patients WS2 and 1 patient WS3. A significant inter and intra-familial clinical heterogeneity was also observed. A sequencing of PAX3 gene in the 6 patients WS1 confirmed the diagnosis in 4 of them by revealing three novel mutations that modify two functional domains of the protein: the c.942delC; the c.933_936dupTTAC and the c.164delTCCGCCACA. These three variations are most likely responsible for the phenotype, however their pathogenic effects need to be confirmed by functional studies. The MLPA analysis of the 2 patients who were sequence negative for PAX3 gene revealed, in one of them, a heterozygous deletion of exons 5 to 9 confirming the WS1 diagnosis. Both clinical and molecular approaches led to the conclusion that there is a lack of genotype-phenotype correlation in WS1, an element that must be taken into account in genetic counseling. The absence of PAX3 mutation in one patient WS1 highlights the fact that the clinical classification is sometimes insufficient to distinguish WS1 from other types WS hence the interest of sequencing the other WS genes in this patient. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. De novo mutations of KIAA2022 in females cause intellectual disability and intractable epilepsy.

    Science.gov (United States)

    de Lange, Iris M; Helbig, Katherine L; Weckhuysen, Sarah; Møller, Rikke S; Velinov, Milen; Dolzhanskaya, Natalia; Marsh, Eric; Helbig, Ingo; Devinsky, Orrin; Tang, Sha; Mefford, Heather C; Myers, Candace T; van Paesschen, Wim; Striano, Pasquale; van Gassen, Koen; van Kempen, Marjan; de Kovel, Carolien G F; Piard, Juliette; Minassian, Berge A; Nezarati, Marjan M; Pessoa, André; Jacquette, Aurelia; Maher, Bridget; Balestrini, Simona; Sisodiya, Sanjay; Warde, Marie Therese Abi; De St Martin, Anne; Chelly, Jamel; van 't Slot, Ruben; Van Maldergem, Lionel; Brilstra, Eva H; Koeleman, Bobby P C

    2016-12-01

    Mutations in the KIAA2022 gene have been reported in male patients with X-linked intellectual disability, and related female carriers were unaffected. Here, we report 14 female patients who carry a heterozygous de novo KIAA2022 mutation and share a phenotype characterised by intellectual disability and epilepsy. Reported females were selected for genetic testing because of substantial developmental problems and/or epilepsy. X-inactivation and expression studies were performed when possible. All mutations were predicted to result in a frameshift or premature stop. 12 out of 14 patients had intractable epilepsy with myoclonic and/or absence seizures, and generalised in 11. Thirteen patients had mild to severe intellectual disability. This female phenotype partially overlaps with the reported male phenotype which consists of more severe intellectual disability, microcephaly, growth retardation, facial dysmorphisms and, less frequently, epilepsy. One female patient showed completely skewed X-inactivation, complete absence of RNA expression in blood and a phenotype similar to male patients. In the six other tested patients, X-inactivation was random, confirmed by a non-significant twofold to threefold decrease of RNA expression in blood, consistent with the expected mosaicism between cells expressing mutant or normal KIAA2022 alleles. Heterozygous loss of KIAA2022 expression is a cause of intellectual disability in females. Compared with its hemizygous male counterpart, the heterozygous female disease has less severe intellectual disability, but is more often associated with a severe and intractable myoclonic epilepsy. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  5. Mutations in c10orf11, a melanocyte-differentiation gene, cause autosomal-recessive albinism.

    Science.gov (United States)

    Grønskov, Karen; Dooley, Christopher M; Østergaard, Elsebet; Kelsh, Robert N; Hansen, Lars; Levesque, Mitchell P; Vilhelmsen, Kaj; Møllgård, Kjeld; Stemple, Derek L; Rosenberg, Thomas

    2013-03-07

    Autosomal-recessive albinism is a hypopigmentation disorder with a broad phenotypic range. A substantial fraction of individuals with albinism remain genetically unresolved, and it has been hypothesized that more genes are to be identified. By using homozygosity mapping of an inbred Faroese family, we identified a 3.5 Mb homozygous region (10q22.2-q22.3) on chromosome 10. The region contains five protein-coding genes, and sequencing of one of these, C10orf11, revealed a nonsense mutation that segregated with the disease and showed a recessive inheritance pattern. Investigation of additional albinism-affected individuals from the Faroe Islands revealed that five out of eight unrelated affected persons had the nonsense mutation in C10orf11. Screening of a cohort of autosomal-recessive-albinism-affected individuals residing in Denmark showed a homozygous 1 bp duplication in C10orf11 in an individual originating from Lithuania. Immunohistochemistry showed localization of C10orf11 in melanoblasts and melanocytes in human fetal tissue, but no localization was seen in retinal pigment epithelial cells. Knockdown of the zebrafish (Danio rerio) homolog with the use of morpholinos resulted in substantially decreased pigmentation and a reduction of the apparent number of pigmented melanocytes. The morphant phenotype was rescued by wild-type C10orf11, but not by mutant C10orf11. In conclusion, we have identified a melanocyte-differentiation gene, C10orf11, which when mutated causes autosomal-recessive albinism in humans. Copyright © 2013 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  6. Loss-of-function mutations in SOX10 cause Kallmann syndrome with deafness.

    Science.gov (United States)

    Pingault, Veronique; Bodereau, Virginie; Baral, Viviane; Marcos, Severine; Watanabe, Yuli; Chaoui, Asma; Fouveaut, Corinne; Leroy, Chrystel; Vérier-Mine, Odile; Francannet, Christine; Dupin-Deguine, Delphine; Archambeaud, Françoise; Kurtz, François-Joseph; Young, Jacques; Bertherat, Jérôme; Marlin, Sandrine; Goossens, Michel; Hardelin, Jean-Pierre; Dodé, Catherine; Bondurand, Nadege

    2013-05-02

    Transcription factor SOX10 plays a role in the maintenance of progenitor cell multipotency, lineage specification, and cell differentiation and is a major actor in the development of the neural crest. It has been implicated in Waardenburg syndrome (WS), a rare disorder characterized by the association between pigmentation abnormalities and deafness, but SOX10 mutations cause a variable phenotype that spreads over the initial limits of the syndrome definition. On the basis of recent findings of olfactory-bulb agenesis in WS individuals, we suspected SOX10 was also involved in Kallmann syndrome (KS). KS is defined by the association between anosmia and hypogonadotropic hypogonadism due to incomplete migration of neuroendocrine gonadotropin-releasing hormone (GnRH) cells along the olfactory, vomeronasal, and terminal nerves. Mutations in any of the nine genes identified to date account for only 30% of the KS cases. KS can be either isolated or associated with a variety of other symptoms, including deafness. This study reports SOX10 loss-of-function mutations in approximately one-third of KS individuals with deafness, indicating a substantial involvement in this clinical condition. Study of SOX10-null mutant mice revealed a developmental role of SOX10 in a subpopulation of glial cells called olfactory ensheathing cells. These mice indeed showed an almost complete absence of these cells along the olfactory nerve pathway, as well as defasciculation and misrouting of the nerve fibers, impaired migration of GnRH cells, and disorganization of the olfactory nerve layer of the olfactory bulbs. Copyright © 2013 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  7. Adaptation of respiratory chain biogenesis to cytochrome c oxidase deficiency caused by SURF1 gene mutations.

    Science.gov (United States)

    Kovářová, Nikola; Cížková Vrbacká, Alena; Pecina, Petr; Stránecký, Viktor; Pronicka, Ewa; Kmoch, Stanislav; Houštěk, Josef

    2012-07-01

    The loss of Surf1 protein leads to a severe COX deficiency manifested as a fatal neurodegenerative disorder, the Leigh syndrome (LS(COX)). Surf1 appears to be involved in the early step of COX assembly but its function remains unknown. The aim of the study was to find out how SURF1 gene mutations influence expression of OXPHOS and other pro-mitochondrial genes and to further characterize the altered COX assembly. Analysis of fibroblast cell lines from 9 patients with SURF1 mutations revealed a 70% decrease of the COX complex content to be associated with 32-54% upregulation of respiratory chain complexes I, III and V and accumulation of Cox5a subunit. Whole genome expression profiling showed a general decrease of transcriptional activity in LS(COX) cells and indicated that the adaptive changes in OXPHOS complexes are due to a posttranscriptional compensatory mechanism. Electrophoretic and WB analysis showed that in mitochondria of LS(COX) cells compared to controls, the assembled COX is present entirely in a supercomplex form, as I-III₂-IV supercomplex but not as larger supercomplexes. The lack of COX also caused an accumulation of I-III₂ supercomplex. The accumulated Cox5a was mainly present as a free subunit. We have found out that the major COX assembly subcomplexes accumulated due to SURF1 mutations range in size between approximately 85-140kDa. In addition to the originally proposed S2 intermediate they might also represent Cox1-containing complexes lacking other COX subunits. Unlike the assembled COX, subcomplexes are unable to associate with complexes I and III. © 2012 Elsevier B.V. All rights reserved.

  8. Somatic mutations in mismatch repair genes in sporadic gastric carcinomas are not a cause but a consequence of the mutator phenotype

    NARCIS (Netherlands)

    Pinto, Mafalda; Wub, Ying; Mensink, Rob G. J.; Cirnes, Luis; Seruca, Raquel; Hofstra, Robert M. W.

    2008-01-01

    In hereditary nonpolyposis colorectal cancer (HNPCC), patients' mismatch repair (MMR) gene mutations cause MMR deficiency, leading to microsatellite instability (MSI-H). MSI-H is also found in a substantial fraction of sporadic gastric carcinomas (SGC), mainly due to MLH1 promoter hypermethylation,

  9. LRPPRC mutations cause early-onset multisystem mitochondrial disease outside of the French-Canadian population.

    Science.gov (United States)

    Oláhová, Monika; Hardy, Steven A; Hall, Julie; Yarham, John W; Haack, Tobias B; Wilson, William C; Alston, Charlotte L; He, Langping; Aznauryan, Erik; Brown, Ruth M; Brown, Garry K; Morris, Andrew A M; Mundy, Helen; Broomfield, Alex; Barbosa, Ines A; Simpson, Michael A; Deshpande, Charu; Moeslinger, Dorothea; Koch, Johannes; Stettner, Georg M; Bonnen, Penelope E; Prokisch, Holger; Lightowlers, Robert N; McFarland, Robert; Chrzanowska-Lightowlers, Zofia M A; Taylor, Robert W

    2015-12-01

    Mitochondrial Complex IV [cytochrome c oxidase (COX)] deficiency is one of the most common respiratory chain defects in humans. The clinical phenotypes associated with COX deficiency include liver disease, cardiomyopathy and Leigh syndrome, a neurodegenerative disorder characterized by bilateral high signal lesions in the brainstem and basal ganglia. COX deficiency can result from mutations affecting many different mitochondrial proteins. The French-Canadian variant of COX-deficient Leigh syndrome is unique to the Saguenay-Lac-Saint-Jean region of Québec and is caused by a founder mutation in the LRPPRC gene. This encodes the leucine-rich pentatricopeptide repeat domain protein (LRPPRC), which is involved in post-transcriptional regulation of mitochondrial gene expression. Here, we present the clinical and molecular characterization of novel, recessive LRPPRC gene mutations, identified using whole exome and candidate gene sequencing. The 10 patients come from seven unrelated families of UK-Caucasian, UK-Pakistani, UK-Indian, Turkish and Iraqi origin. They resemble the French-Canadian Leigh syndrome patients in having intermittent severe lactic acidosis and early-onset neurodevelopmental problems with episodes of deterioration. In addition, many of our patients have had neonatal cardiomyopathy or congenital malformations, most commonly affecting the heart and the brain. All patients who were tested had isolated COX deficiency in skeletal muscle. Functional characterization of patients' fibroblasts and skeletal muscle homogenates showed decreased levels of mutant LRPPRC protein and impaired Complex IV enzyme activity, associated with abnormal COX assembly and reduced steady-state levels of numerous oxidative phosphorylation subunits. We also identified a Complex I assembly defect in skeletal muscle, indicating different roles for LRPPRC in post-transcriptional regulation of mitochondrial mRNAs between tissues. Patient fibroblasts showed decreased steady-state levels

  10. [Mutation analyses and prenatal diagnosis in two families of X linked severe combined immunodeficiency caused by IL2RG gene novel mutation].

    Science.gov (United States)

    Kong, Xiangdong; Liu, Ning; Xu, Xueju; Wu, Qinghua; Zhao, Zhenhua; Bai, Qiaoling; Meng, Jingjing

    2014-04-29

    To evaluate the diagnostic feasibility of mutation analysis and prenatal genetic diagnosis genetic analysis of IL2RG gene in two families with a birth history of X-linked severe combined immunodeficiency (X-SCID). Blood samples of a male infant patient of X-SCID and his mother in family 1 and the parents of another deceased child with X-SCID in family 2 from January 2012 to February 2013 were collected.Eight exons comprising IL2RG open reading frame and their exon/intron boundaries were analyzed by bi-directional direct sequencing of polymerase chain reaction (PCR) products. Prenatal genetic diagnoses were performed by chorionic villus sampling after the genotypes of maternal probands were identified in family 1. Two mutations of IL2RG gene were identified in these two families. The c.361-363delGAG (p.E121del) mutation was identified in family 1. The c.510-511insGAACT (p.W173X) mutation appeared in family 2. The two mutations of c.361-363delGAG (p.E121del) and c.510-511insGAACT (p.W173X) were novel. The two novel mutations were absent in 100 normal controls. The pregnancy in family 1 continued and the infant showed no symptom of X-SCID at 1 year after birth. The aunt (II-3) of proband in family 1 was not a carrier. The female fetus in family 1 had no mutation. Two novel mutations of c.361-363delGAG (p.E121del) and c.510-511insGAACT (p.W173X) in IL2RG gene may be a major cause of disease in two families with X-SCID. And direct sequencing of IL2RG gene provides genetic counseling, prenatal diagnosis and carrier screening for families with X-SCID.

  11. MASA syndrome is caused by mutations in the neural cell adhesion gene, L1CAM

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, C.E.; Wang, Y.; Schroer, R.J.; Stevenson, R.E. [Greenwood Genetic Center, SC (United States)

    1994-09-01

    The MASA syndrome is a recessive X-linked disorder characterized by Mental retardation, Adducted thumbs, Shuffling gait and Aphasia. Recently we found that MASA in one family was likely caused by a point mutation in exon 6 of the L1CAM gene. This gene has also been shown to be involved in X-linked hydrocephalus (HSAS). We have screened 60 patients with either sporadic HSAS or MASA as well as two additional families with MASA. For the screening, we initially utilized 3 cDNA probes for the L1CAM gene. In one of the MASA families, K8310, two affected males were found to have an altered BglII band. The band was present in their carrier mother but not in their normal brothers. This band was detected by the entire cDNA probe as well as the cDNA probe for 3{prime} end of the gene. Analysis of the L1CAM sequence indicated the altered BglII site is distal to the exon 28 but proximal to the punative poly A signal site. It is hypothesized that this point mutation alters the stability of the L1CAM mRNA. This is being tested using cell lines established from the two affected males.

  12. Loss-of-function mutations in HOXC13 cause pure hair and nail ectodermal dysplasia.

    Science.gov (United States)

    Lin, Zhimiao; Chen, Quan; Shi, Lei; Lee, Mingyang; Giehl, Kathrin A; Tang, Zhanli; Wang, Huijun; Zhang, Jie; Yin, Jinghua; Wu, Lingshen; Xiao, Ruo; Liu, Xuanzhu; Dai, Lanlan; Zhu, Xuejun; Li, Ruoyu; Betz, Regina C; Zhang, Xue; Yang, Yong

    2012-11-02

    Pure hair and nail ectodermal dysplasia (PHNED) is a congenital condition characterized by hypotrichosis and nail dystrophy. Autosomal-recessive PHNED has previously been mapped to chromosomal region 12q12-q14.1, which contains the type II hair keratin and HOXC clusters. Hoxc13-null mice are known to develop hair and nail defects very similar to those seen in human PHNED. We performed whole-exome sequencing in a consanguineous Chinese family affected by PHNED and identified a homozygous nonsense mutation (c.390C>A [p.Tyr130(∗)]) in HOXC13 in all affected individuals. In an additional affected female from a consanguineous Afghan family, we found a 27.6 kb homozygous microdeletion involving the first exon of HOXC13. We examined HOXC13 expression in scalp specimen obtained from the index individual of the Chinese family and detected dramatically reduced mRNA levels in skin tissue and nearly absent protein staining in hair follicles, suggesting a mechanism of nonsense-mediated mRNA decay. We also observed markedly decreased expression of four HOXC13 target genes in the specimen. Taken together, our results demonstrate that loss-of-function mutations in HOXC13 cause autosomal-recessive PHNED and further highlight the importance of HOXC13 in hair and nail development. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  13. PRKAR1A mutation causing pituitary-dependent Cushing disease in a patient with Carney complex.

    Science.gov (United States)

    Kiefer, Florian W; Winhofer, Yvonne; Iacovazzo, Donato; Korbonits, Márta; Wolfsberger, Stefan; Knosp, Engelbert; Trautinger, Franz; Höftberger, Romana; Krebs, Michael; Luger, Anton; Gessl, Alois

    2017-08-01

    Carney complex (CNC) is an autosomal dominant condition caused, in most cases, by an inactivating mutation of the PRKAR1A gene, which encodes for the type 1 alpha regulatory subunit of protein kinase A. CNC is characterized by the occurrence of endocrine overactivity, myxomas and typical skin manifestations. Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD) is the most frequent endocrine disease observed in CNC. Here, we describe the first case of a patient with CNC and adrenocorticotropic hormone (ACTH)-dependent Cushing disease due to a pituitary corticotroph adenoma. Loss-of-heterozygosity analysis of the pituitary tumour revealed loss of the wild-type copy of PRKAR1A , suggesting a role of this gene in the pituitary adenoma development. PRKAR1A loss-of-function mutations can rarely lead to ACTH-secreting pituitary adenomas in CNC patients. Pituitary-dependent disease should be considered in the differential diagnosis of Cushing syndrome in CNC patients. © 2017 European Society of Endocrinology.

  14. Two α1-Globin Gene Point Mutations Causing Severe Hb H Disease.

    Science.gov (United States)

    Jiang, Hua; Huang, Lv-Yin; Zhen, Li; Jiang, Fan; Li, Dong-Zhi

    Hb H disease is generally a moderate form of α-thalassemia (α-thal) that rarely requires regular blood transfusions. In this study, two Chinese families with members carrying transfusion-dependent Hb H disease were investigated for rare mutations on the α-globin genes (HBA1, HBA2). In one family, Hb Zürich-Albisrieden [α59(E8)Gly→Arg; HBA1: c.178G>C] in combination with the Southeast Asian (- - SEA ) deletion was the defect responsible for the severe phenotype. In another family, a novel hemoglobin (Hb) variant named Hb Sichuan (HBA1: c.393_394insT), causes α-thal and a severe phenotype when associated with the - - SEA deletion. As these two HBA1 mutations can present as continuous blood transfusion-dependent α-thal, it is important to take this point into account for detecting the carriers, especially in couples in which one partner is already a known α 0 -thal carrier.

  15. Homozygous Mutations in PXDN Cause Congenital Cataract, Corneal Opacity, and Developmental Glaucoma

    Science.gov (United States)

    Khan, Kamron; Rudkin, Adam; Parry, David A.; Burdon, Kathryn P.; McKibbin, Martin; Logan, Clare V.; Abdelhamed, Zakia I.A.; Muecke, James S.; Fernandez-Fuentes, Narcis; Laurie, Kate J.; Shires, Mike; Fogarty, Rhys; Carr, Ian M.; Poulter, James A.; Morgan, Joanne E.; Mohamed, Moin D.; Jafri, Hussain; Raashid, Yasmin; Meng, Ngy; Piseth, Horm; Toomes, Carmel; Casson, Robert J.; Taylor, Graham R.; Hammerton, Michael; Sheridan, Eamonn; Johnson, Colin A.; Inglehearn, Chris F.; Craig, Jamie E.; Ali, Manir

    2011-01-01

    Anterior segment dysgenesis describes a group of heterogeneous developmental disorders that affect the anterior chamber of the eye and are associated with an increased risk of glaucoma. Here, we report homozygous mutations in peroxidasin (PXDN) in two consanguineous Pakistani families with congenital cataract-microcornea with mild to moderate corneal opacity and in a consanguineous Cambodian family with developmental glaucoma and severe corneal opacification. These results highlight the diverse ocular phenotypes caused by PXDN mutations, which are likely due to differences in genetic background and environmental factors. Peroxidasin is an extracellular matrix-associated protein with peroxidase catalytic activity, and we confirmed localization of the protein to the cornea and lens epithelial layers. Our findings imply that peroxidasin is essential for normal development of the anterior chamber of the eye, where it may have a structural role in supporting cornea and lens architecture as well as an enzymatic role as an antioxidant enzyme in protecting the lens, trabecular meshwork, and cornea against oxidative damage. PMID:21907015

  16. GABRB3 mutations: a new and emerging cause of early infantile epileptic encephalopathy.

    Science.gov (United States)

    Papandreou, Apostolos; McTague, Amy; Trump, Natalie; Ambegaonkar, Gautam; Ngoh, Adeline; Meyer, Esther; Scott, Richard H; Kurian, Manju A

    2016-04-01

    The gamma-aminobutyric acid type A receptor β3 gene (GABRB3) encodes the β3-subunit of the gamma-aminobutyric acid type A (GABAA ) receptor, which mediates inhibitory signalling within the central nervous system. Recently, GABRB3 mutations have been identified in a few patients with infantile spasms and Lennox-Gastaut syndrome. We report the clinical and electrographic features of a novel case of GABRB3-related early-onset epileptic encephalopathy. Our patient presented with neonatal hypotonia and feeding difficulties, then developed pharmacoresistant epileptic encephalopathy, characterized by multiple seizure types from 3 months of age. Electroencephalography demonstrated ictal generalized and interictal multifocal epileptiform abnormalities. Using a SureSelectXT custom multiple gene panel covering 48 early infantile epileptic encephalopathy/developmental delay genes, a novel de novo GABRB3 heterozygous missense mutation, c.860C>T (p.Thr287Ile), was identified and confirmed on Sanger sequencing. GABRB3 is an emerging cause of early-onset epilepsy. Novel genetic technologies, such as whole-exome/genome sequencing and multiple gene panels, will undoubtedly identify further cases, allowing more detailed electroclinical delineation of the GABRB3-related genotypic and phenotypic spectra. © 2015 The Authors. Developmental Medicine & Child Neurology published by John Wiley & Sons Ltd on behalf of Mac Keith Press.

  17. Mutations in SNRPB, encoding components of the core splicing machinery, cause cerebro-costo-mandibular syndrome.

    Science.gov (United States)

    Bacrot, Séverine; Doyard, Mathilde; Huber, Céline; Alibeu, Olivier; Feldhahn, Niklas; Lehalle, Daphné; Lacombe, Didier; Marlin, Sandrine; Nitschke, Patrick; Petit, Florence; Vazquez, Marie-Paule; Munnich, Arnold; Cormier-Daire, Valérie

    2015-02-01

    Cerebro-costo-mandibular syndrome (CCMS) is a developmental disorder characterized by the association of Pierre Robin sequence and posterior rib defects. Exome sequencing and Sanger sequencing in five unrelated CCMS patients revealed five heterozygous variants in the small nuclear ribonucleoprotein polypeptides B and B1 (SNRPB) gene. This gene includes three transcripts, namely transcripts 1 and 2, encoding components of the core spliceosomal machinery (SmB' and SmB) and transcript 3 undergoing nonsense-mediated mRNA decay. All variants were located in the premature termination codon (PTC)-introducing alternative exon of transcript 3. Quantitative RT-PCR analysis revealed a significant increase in transcript 3 levels in leukocytes of CCMS individuals compared to controls. We conclude that CCMS is due to heterozygous mutations in SNRPB, enhancing inclusion of a SNRPB PTC-introducing alternative exon, and show that this developmental disease is caused by defects in the splicing machinery. Our finding confirms the report of SNRPB mutations in CCMS patients by Lynch et al. (2014) and further extends the clinical and molecular observations. © 2014 WILEY PERIODICALS, INC.

  18. Mutations of LRTOMT, a fusion gene with alternative reading frames, cause nonsyndromic deafness in humans

    Science.gov (United States)

    Ahmed, Zubair M; Masmoudi, Saber; Kalay, Ersan; Belyantseva, Inna A; Mosrati, Mohamed Ali; Collin, Rob W J; Riazuddin, Saima; Hmani-Aifa, Mounira; Venselaar, Hanka; Kawar, Mayya N; Abdelaziz, Tlili; van der Zwaag, Bert; Khan, Shahid Y; Ayadi, Leila; Riazuddin, S Amer; Morell, Robert J; Griffith, Andrew J; Charfedine, Ilhem; Çaylan, Refik; Oostrik, Jaap; Karaguzel, Ahmet; Ghorbel, Abdelmonem; Riazuddin, Sheikh; Friedman, Thomas B; Ayadi, Hammadi; Kremer, Hannie

    2012-01-01

    Many proteins necessary for sound transduction have been discovered through positional cloning of genes that cause deafness1–3. In this study, we report that mutations of LRTOMT are associated with profound non-syndromic hearing loss at the DFNB63 locus on human chromosome 11q13.3-q13.4. LRTOMT has two alternative reading frames and encodes two different proteins, LRTOMT1 and LRTOMT2, that are detected by Western blot analyses. LRTOMT2 is a putative methyltransferase. During evolution, novel transcripts can arise through partial or complete coalescence of genes4. We provide evidence that in the primate lineage LRTOMT evolved from the fusion of two neighboring ancestral genes, which exist as separate genes (Lrrc51and Tomt) in rodents. PMID:18953341

  19. Heterozygosity for a Bub1 mutation causes female-specific germ cell aneuploidy in mice

    Energy Technology Data Exchange (ETDEWEB)

    Leland, Shawn; Nagarajan, Prabakaran; Polyzos, Aris; Thomas, Sharon; Samaan, George; Donnell, Robert; Marchetti, Francesco; Venkatachalam, Sundaresan

    2009-06-24

    Aneuploidy, the most common chromosomal abnormality at birth and the main ascertained cause of pregnancy loss in humans, originates primarily from chromosome segregation errors during oogenesis. Here we report that heterozygosity for a mutation in the mitotic checkpoint kinase gene, Bub1, induces aneuploidy in female germ cells of mice, and that the effect increases with advancing maternal age. Analysis of Bub1 heterozygous oocytes showed that aneuploidy occurred primarily during the first meiotic division and involved premature sister chromatid separation. Furthermore, aneuploidy was inherited in zygotes and resulted in the loss of embryos after implantation. The incidence of aneuploidy in zygotes was sufficient to explain the reduced litter size in matings with Bub1 heterozygous females. No effects were seen in germ cells from heterozygous males. These findings show that Bub1 dysfunction is linked to inherited aneuploidy in female germ cells and may contribute to the maternal age-related increase in aneuploidy and pregnancy loss.

  20. Mutations in Three Genes Encoding Proteins Involved in Hair Shaft Formation Cause Uncombable Hair Syndrome

    DEFF Research Database (Denmark)

    Ü Basmanav, F Buket; Cau, Laura; Tafazzoli, Aylar

    2016-01-01

    Uncombable hair syndrome (UHS), also known as "spun glass hair syndrome," "pili trianguli et canaliculi," or "cheveux incoiffables" is a rare anomaly of the hair shaft that occurs in children and improves with age. UHS is characterized by dry, frizzy, spangly, and often fair hair that is resistant...... in the majority of UHS case subjects. The two enzymes PADI3 and TGM3, responsible for posttranslational protein modifications, and their target structural protein TCHH are all involved in hair shaft formation. Elucidation of the molecular outcomes of the disease-causing mutations by cell culture experiments...... and tridimensional protein models demonstrated clear differences in the structural organization and activity of mutant and wild-type proteins. Scanning electron microscopy observations revealed morphological alterations in hair coat of Padi3 knockout mice. All together, these findings elucidate the molecular genetic...

  1. A de novo missense mutation of FGFR2 causes facial dysplasia syndrome in Holstein cattle

    DEFF Research Database (Denmark)

    Agerholm, Jørgen Steen; McEvoy, Fintan; Heegaard, Steffen

    2017-01-01

    Background Surveillance for bovine genetic diseases in Denmark identified a hitherto unreported congenital syndrome occurring among progeny of a Holstein sire used for artificial breeding. A genetic aetiology due to a dominant inheritance with incomplete penetrance or a mosaic germline mutation...... was suspected as all recorded cases were progeny of the same sire. Detailed investigations were performed to characterize the syndrome and to reveal its cause. Results Seven malformed calves were submitted examination. All cases shared a common morphology with the most striking lesions being severe facial...... dysplasia and complete prolapse of the eyes. Consequently the syndrome was named facial dysplasia syndrome (FDS). Furthermore, extensive brain malformations, including microencephaly, hydrocephalus, lobation of the cerebral hemispheres and compression of the brain were present. Subsequent data analysis...

  2. Clinical Features of a Family with Multiple Endocrine Neoplasia Type 2A Caused by the D631Y RET Mutation.

    Science.gov (United States)

    Ospina, Naykky Singh; Maraka, Spyridoula; Donegan, Diane; Morris, John C

    2017-10-01

    We describe a family with multiple endocrine neoplasia type 2A (MEN2A) caused by the D631Y RET mutation resulting in an atypical phenotype. The index case was a 24-year-old man with history of recurrent anaplastic ependymoma incidentally found to have the D631Y RET mutation. At first assessment, four family members had evidence of large pheochromocytomas. One patient was found to have micromedullary thyroid cancer at 79 years of age. None of the patients had primary hyperparathyroidism. Patients with MEN2A caused by a D631Y RET mutation most commonly present with pheochromocytomas. Medullary thyroid cancer is a less common part of the syndrome when compared with other RET mutations.

  3. STXBP1 mutations cause not only Ohtahara syndrome but also West syndrome--result of Japanese cohort study.

    Science.gov (United States)

    Otsuka, Motoko; Oguni, Hirokazu; Liang, Jao-Shwann; Ikeda, Hiroko; Imai, Katsumi; Hirasawa, Kyoko; Imai, Kaoru; Tachikawa, Emiko; Shimojima, Keiko; Osawa, Makiko; Yamamoto, Toshiyuki

    2010-12-01

    We performed STXBP1 mutation analyses in 86 patients with various types of epilepsies, including 10 patients with OS, 43 with West syndrome, 2 with Lennox-Gastaut syndrome, 12 with symptomatic generalized epilepsy, 14 with symptomatic partial epilepsy, and 5 with other undetermined types of epilepsy. In all patients, the etiology was unknown, but ARX and CDKL5 mutations were negative in all cases. All coding exons of STXBP1 were analyzed by direct-sequencing. Two de novo nucleotide alterations of STXBP1 were identified in two patients with Ohtahara and West syndrome, respectively. No de novo or deleterious mutations in STXBP1 were found in the remaining 84 patients with various types of symptomatic epilepsies. This is the first case report showing that STXBP1 mutations caused West syndrome from the onset of epilepsy. STXBP1 analysis should be considered as an etiology of symptomatic West syndrome without explainable cause. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

  4. A novel splicing mutation in COL1A1 gene caused type I osteogenesis imperfecta in a Chinese family.

    Science.gov (United States)

    Peng, Hao; Zhang, Yuhui; Long, Zhigao; Zhao, Ding; Guo, Zhenxin; Xue, Jinjie; Xie, Zhiguo; Xiong, Zhimin; Xu, Xiaojuan; Su, Wei; Wang, Bing; Xia, Kun; Hu, Zhengmao

    2012-07-10

    Osteogenesis imperfect (OI) is a heritable connective tissue disorder with bone fragility as a cardinal manifestation, accompanied by short stature, dentinogenesis imperfecta, hyperlaxity of ligaments and skin, blue sclerae and hearing loss. Dominant form of OI is caused by mutations in the type I procollagen genes, COL1A1/A2. Here we identified a novel splicing mutation c.3207+1G>A (GenBank ID: JQ236861) in the COL1A1 gene that caused type I OI in a Chinese family. RNA splicing analysis proved that this mutation created a new splicing site at c.3200, and then led to frameshift. This result further enriched the mutation spectrum of type I procollagen genes. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. De Novo Mutations in PDE10A Cause Childhood-Onset Chorea with Bilateral Striatal Lesions.

    Science.gov (United States)

    Mencacci, Niccolò E; Kamsteeg, Erik-Jan; Nakashima, Kosuke; R'Bibo, Lea; Lynch, David S; Balint, Bettina; Willemsen, Michèl A A P; Adams, Matthew E; Wiethoff, Sarah; Suzuki, Kazunori; Davies, Ceri H; Ng, Joanne; Meyer, Esther; Veneziano, Liana; Giunti, Paola; Hughes, Deborah; Raymond, F Lucy; Carecchio, Miryam; Zorzi, Giovanna; Nardocci, Nardo; Barzaghi, Chiara; Garavaglia, Barbara; Salpietro, Vincenzo; Hardy, John; Pittman, Alan M; Houlden, Henry; Kurian, Manju A; Kimura, Haruhide; Vissers, Lisenka E L M; Wood, Nicholas W; Bhatia, Kailash P

    2016-04-07

    Chorea is a hyperkinetic movement disorder resulting from dysfunction of striatal medium spiny neurons (MSNs), which form the main output projections from the basal ganglia. Here, we used whole-exome sequencing to unravel the underlying genetic cause in three unrelated individuals with a very similar and unique clinical presentation of childhood-onset chorea and characteristic brain MRI showing symmetrical bilateral striatal lesions. All individuals were identified to carry a de novo heterozygous mutation in PDE10A (c.898T>C [p.Phe300Leu] in two individuals and c.1000T>C [p.Phe334Leu] in one individual), encoding a phosphodiesterase highly and selectively present in MSNs. PDE10A contributes to the regulation of the intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Both substitutions affect highly conserved amino acids located in the regulatory GAF-B domain, which, by binding to cAMP, stimulates the activity of the PDE10A catalytic domain. In silico modeling showed that the altered residues are located deep in the binding pocket, where they are likely to alter cAMP binding properties. In vitro functional studies showed that neither substitution affects the basal PDE10A activity, but they severely disrupt the stimulatory effect mediated by cAMP binding to the GAF-B domain. The identification of PDE10A mutations as a cause of chorea further motivates the study of cAMP signaling in MSNs and highlights the crucial role of striatal cAMP signaling in the regulation of basal ganglia circuitry. Pharmacological modulation of this pathway could offer promising etiologically targeted treatments for chorea and other hyperkinetic movement disorders. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  6. A Turkish family with Sjögren-Larsson syndrome caused by a novel ALDH3A2 mutation

    Directory of Open Access Journals (Sweden)

    Faruk Incecik

    2013-01-01

    Full Text Available Sjögren-Larsson syndrome (SLS is an inherited neurocutaneous disorder caused by mutations in the aldehyde dehydrogenase family 3 member A2 (ALDH3A2 gene that encodes fatty aldehyde dehydrogenase. Affected patients display ichthyosis, mental retardation, and spastic diplegia. More than 70 mutations in ALDH3A2 have been discovered in SLS patients. We diagnosed two brothers age of 12 and 20 years with characteristic features of this rare syndrome. Magnetic resonance imaging showed demyelinating disease in both of them. We described a novel homozygous, c. 835 T > A (p.Y279N mutation in exon 6 in two patients.

  7. Early onset of hypokalaemic periodic paralysis caused by a novel mutation of the CACNA1S gene.

    Science.gov (United States)

    Chabrier, S; Monnier, N; Lunardi, J

    2008-10-01

    We report a precocious and atypical form of hypokalaemic periodic paralysis, with clinical manifestations at birth and first episodes of paralysis occurring as early as 1 year of age, although onset of this disease usually occurs between 5-35 years. Extensive molecular analysis showed that the disease was caused by a novel de novo p.Arg897Ser mutation in the CACNA1S gene. The mutation mapped to a new region of the protein, the S4 voltage sensing segment of domain III, at odds with previously reported mutations that exclusively affected domains II and IV.

  8. Stickler syndrome caused by COL2A1 mutations: genotype-phenotype correlation in a series of 100 patients

    DEFF Research Database (Denmark)

    Hoornaert, Kristien P; Vereecke, Inge; Dewinter, Chantal

    2010-01-01

    Stickler syndrome is an autosomal dominant connective tissue disorder caused by mutations in different collagen genes. The aim of our study was to define more precisely the phenotype and genotype of Stickler syndrome type 1 by investigating a large series of patients with a heterozygous mutation...... in COL2A1. In 188 probands with the clinical diagnosis of Stickler syndrome, the COL2A1 gene was analyzed by either a mutation scanning technique or bidirectional fluorescent DNA sequencing. The effect of splice site alterations was investigated by analyzing mRNA. Multiplex ligation...... with Stickler syndrome....

  9. Further evidence that mutations in INS can be a rare cause of Maturity-Onset Diabetes of the Young (MODY)

    DEFF Research Database (Denmark)

    Boesgaard, Trine W; Pruhova, Stepanka; Andersson, Ehm A

    2010-01-01

    BACKGROUND: Insulin gene (INS) mutations have recently been described as a common cause of permanent neonatal diabetes (PNDM) and a rare cause of diabetes diagnosed in childhood or adulthood. METHODS: INS was sequenced in 116 maturity-onset diabetes of the young (MODYX) patients (n = 48 Danish...

  10. Treacher Collins syndrome with craniosynostosis, choanal atresia, and esophageal regurgitation caused by a novel nonsense mutation in TCOF1.

    Science.gov (United States)

    Horiuchi, Katsumi; Ariga, Tadashi; Fujioka, Hirotaka; Kawashima, Kunihiro; Yamamoto, Yuhei; Igawa, Hiroharu; Sakiyama, Yukio; Sugihara, Tsuneki

    2004-07-15

    Treacher Collins syndrome (TCS) is caused by mutations in TCOF1 of the nonsense, small deletion, and small insertion types, which most likely result in haploinsufficiency. We report a novel de novo nonsense mutation 2731C --> T, resulting in Arg911Stop, which truncates the protein. Our patient had the classic findings of TCS, but with documented craniosynostosis, choanal atresia, and esophageal regurgitation. Copyright 2004 Wiley-Liss, Inc.

  11. Murine muscular dystrophy caused by a mutation in the laminin alpha 2 (Lama2) gene

    DEFF Research Database (Denmark)

    Xu, H; Wu, X R; Wewer, U M

    1994-01-01

    The classic murine muscular dystrophy strain, dy, was first described almost 40 years ago. We have identified the molecular basis of an allele of dy, called dy2J, by detecting a mutation in the laminin alpha 2 chain gene--the first identified mutation in laminin-2. The G to A mutation in a splice...

  12. Waardenburg syndrome type II in a Chinese patient caused by a novel nonsense mutation in the SOX10 gene.

    Science.gov (United States)

    Ma, Jing; Zhang, Tie-Song; Lin, Ken; Sun, Hao; Jiang, Hong-Chao; Yang, Yan-Li; Low, Fan; Gao, Ying-Qin; Ruan, Biao

    2016-06-01

    Waardenburg syndrome is a congenital genetic disorder. It is the most common type of syndromic hearing impairment with highly genetic heterogeneity and proved to be related by 6 genes as follows: PAX3, MITF, SNAI2, EDN3, EDNRB and SOX10. This article aims to identify the genetic causes of a Chinese WS child patient. A Chinese WS child was collected for clinical data collection by questionnaire survey. DNA samples of proband and his parents were extracted from peripheral blood samples. Six candidate genes were sequenced by the Trusight One sequencing panel on the illumina NextSeq 500 platform. A novel nonsense heterozygous mutation was found in the coding region of exon 2 in the SOX10 gene of proband. The novel nonsense heterozygous mutation could cause the replacement of the 55th lysine codon by stop codon (484T > C, C142R) and further more possibly cause terminating the protein translation in advance. However, both proband's parents had no mutation of genes above mentioned. The gene mutation of SOX10 [NM_006941.3 c.163A > T] is a novel nonsense mutation. No record of this mutation has been found in dbSNP, HGMD, 1000 Genomes Project, ClinVar and ESP6500 databases. It meets the condition of PS2 of strong evidence in 2015 ACMG Standards and Guidelines. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Mutation analyses and prenatal diagnosis in families of X-linked severe combined immunodeficiency caused by IL2Rγ gene novel mutation.

    Science.gov (United States)

    Bai, Q L; Liu, N; Kong, X D; Xu, X J; Zhao, Z H

    2015-06-11

    We investigated the feasibility of interleukin-2 receptor gamma (IL2Rγ) gene based on gene mutation analysis and pre-natal diagnosis of X-linked severe combined immunodeficiency (X-SCID). Blood samples of patients and their parents of X-SCID (family 1) and X-SCID (family 2) were collected. IL2Rγ gene sequences of the 2 families were analyzed using bi-directional direct sequencing by polymerase chain reaction. DNA sequence changes in the IL2Rγ gene exon region and shear zone were also analyzed. We also sequenced the IL2Rγ gene in 100 healthy individuals. Prenatal genetic diagnoses for a high-risk fetus in family 1 were performed by chorionic villus sampling after determining each family's genotypes. The suspect fe-male in family 1 underwent carrier detection. Two novel mutations of IL2Rγ gene were identified, including c.361-363delGAG (p.E121del) in the patient and his mother in family 1, and c.510-511insGAACT (p.W173X) heterozygous mutation in the proband's mother in family 2. These mutations were absent in the 100 controls. Prenatal diagnosis of early pregnancy in the female fetus of family 1 was performed; the fetus was heterozygous, which was confirmed at postnatal follow-up. The suspect female in family 1 showed no mutation in carrier detection. The novel p.E121del and p.W173X mutations in IL2Rγ may have been the primary causes of disease in 2 families with X-SCID. In couples with an X-SCID reproductive history, prenatal gene mutation analysis of IL2Rγ can effectively prevent the birth of children with X-SCID and carrier detection for suspected females.

  14. Biallelic CACNA1A mutations cause early onset epileptic encephalopathy with progressive cerebral, cerebellar, and optic nerve atrophy.

    Science.gov (United States)

    Reinson, Karit; Õiglane-Shlik, Eve; Talvik, Inga; Vaher, Ulvi; Õunapuu, Anne; Ennok, Margus; Teek, Rita; Pajusalu, Sander; Murumets, Ülle; Tomberg, Tiiu; Puusepp, Sanna; Piirsoo, Andres; Reimand, Tiia; Õunap, Katrin

    2016-08-01

    The CACNA1A gene encodes the transmembrane pore-forming alpha-1A subunit of the Cav 2.1 P/Q-type voltage-gated calcium channel. Several heterozygous mutations within this gene, including nonsense mutations, missense mutations, and expansion of cytosine-adenine-guanine repeats, are known to cause three allelic autosomal dominant conditions-episodic ataxia type 2, familial hemiplegic migraine type 1, and spinocerebellar ataxia type 6. An association with epilepsy and CACNA1A mutations has also been described. However, the link with epileptic encephalopathies has emerged only recently. Here we describe two patients, sister and brother, with compound heterozygous mutations in CACNA1A. Exome sequencing detected biallelic mutations in CACNA1A: A missense mutation c.4315T>A (p.Trp1439Arg) in exon 27, and a seven base pair deletion c.472_478delGCCTTCC (p.Ala158Thrfs*6) in exon 3. Both patients were normal at birth, but developed daily recurrent seizures in early infancy with concomitant extreme muscular hypotonia, hypokinesia, and global developmental delay. The brain MRI images showed progressive cerebral, cerebellar, and optic nerve atrophy. At the age of 5, both patients were blind and bedridden with a profound developmental delay. The elder sister died at that age. Their parents and two siblings were heterozygotes for one of those pathogenic mutations and expressed a milder phenotype. Both of them have intellectual disability and in addition the mother has adult onset cerebellar ataxia with a slowly progressive cerebellar atrophy. Compound heterozygous mutations in the CACNA1A gene presumably cause early onset epileptic encephalopathy, and progressive cerebral, cerebellar and optic nerve atrophy with reduced lifespan. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Mutations in POGLUT1, encoding protein O-glucosyltransferase 1, cause autosomal-dominant Dowling-Degos disease.

    Science.gov (United States)

    Basmanav, F Buket; Oprisoreanu, Ana-Maria; Pasternack, Sandra M; Thiele, Holger; Fritz, Günter; Wenzel, Jörg; Größer, Leopold; Wehner, Maria; Wolf, Sabrina; Fagerberg, Christina; Bygum, Anette; Altmüller, Janine; Rütten, Arno; Parmentier, Laurent; El Shabrawi-Caelen, Laila; Hafner, Christian; Nürnberg, Peter; Kruse, Roland; Schoch, Susanne; Hanneken, Sandra; Betz, Regina C

    2014-01-02

    Dowling-Degos disease (DDD) is an autosomal-dominant genodermatosis characterized by progressive and disfiguring reticulate hyperpigmentation. We previously identified loss-of-function mutations in KRT5 but were only able to detect pathogenic mutations in fewer than half of our subjects. To identify additional causes of DDD, we performed exome sequencing in five unrelated affected individuals without mutations in KRT5. Data analysis identified three heterozygous mutations from these individuals, all within the same gene. These mutations, namely c.11G>A (p.Trp4*), c.652C>T (p.Arg218*), and c.798-2A>C, are within POGLUT1, which encodes protein O-glucosyltransferase 1. Further screening of unexplained cases for POGLUT1 identified six additional mutations, as well as two of the above described mutations. Immunohistochemistry of skin biopsies of affected individuals with POGLUT1 mutations showed significantly weaker POGLUT1 staining in comparison to healthy controls with strong localization of POGLUT1 in the upper parts of the epidermis. Immunoblot analysis revealed that translation of either wild-type (WT) POGLUT1 or of the protein carrying the p.Arg279Trp substitution led to the expected size of about 50 kDa, whereas the c.652C>T (p.Arg218*) mutation led to translation of a truncated protein of about 30 kDa. Immunofluorescence analysis identified a colocalization of the WT protein with the endoplasmic reticulum and a notable aggregating pattern for the truncated protein. Recently, mutations in POFUT1, which encodes protein O-fucosyltransferase 1, were also reported to be responsible for DDD. Interestingly, both POGLUT1 and POFUT1 are essential regulators of Notch activity. Our results furthermore emphasize the important role of the Notch pathway in pigmentation and keratinocyte morphology. Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  16. Familial Ehlers-Danlos syndrome with lethal arterial events caused by a mutation in COL5A1.

    Science.gov (United States)

    Monroe, Glen R; Harakalova, Magdalena; van der Crabben, Saskia N; Majoor-Krakauer, Danielle; Bertoli-Avella, Aida M; Moll, Frans L; Oranen, Björn I; Dooijes, Dennis; Vink, Aryan; Knoers, Nine V; Maugeri, Alessandra; Pals, Gerard; Nijman, Isaac J; van Haaften, Gijs; Baas, Annette F

    2015-06-01

    Different forms of Ehlers-Danlos syndrome (EDS) exist, with specific phenotypes and associated genes. Vascular EDS, caused by heterozygous mutations in the COL3A1 gene, is characterized by fragile vasculature with a high risk of catastrophic vascular events at a young age. Classic EDS, caused by heterozygous mutations in the COL5A1 or COL5A2 genes, is characterized by fragile, hyperextensible skin and joint laxity. To date, vessel rupture in four unrelated classic EDS patients with a confirmed COL5A1 mutation has been reported. We describe familial occurrence of a phenotype resembling vascular EDS in a mother and her two sons, who all died at an early age from arterial ruptures. Diagnostic Sanger sequencing in the proband failed to detect aberrations in COL3A1, COL1A1, COL1A2, TGFBR1, TGFBR2, SMAD3, and ACTA2. Next, the proband's DNA was analyzed using a next-generation sequencing approach targeting 554 genes linked to vascular disease (VASCULOME project). A novel heterozygous mutation in COL5A1 was detected, resulting in an essential glycine substitution at the C-terminal end of the triple helix domain (NM_000093.4:c.4610G>T; p.Gly1537Val). This mutation was also present in DNA isolated from autopsy material of the index's brother. No material was available from the mother, but the mutation was excluded in her parents, siblings and in the father of her sons, suggesting that the COL5A1 mutation occurred in the mother's genome de novo. In conclusion, we report familial occurrence of lethal arterial events caused by a COL5A1 mutation. © 2015 Wiley Periodicals, Inc.

  17. Colon cancer-associated mutator DNA polymerase δ variant causes expansion of dNTP pools increasing its own infidelity.

    Science.gov (United States)

    Mertz, Tony M; Sharma, Sushma; Chabes, Andrei; Shcherbakova, Polina V

    2015-05-12

    Defects in DNA polymerases δ (Polδ) and ε (Polε) cause hereditary colorectal cancer and have been implicated in the etiology of some sporadic colorectal and endometrial tumors. We previously reported that the yeast pol3-R696W allele mimicking a human cancer-associated variant, POLD1-R689W, causes a catastrophic increase in spontaneous mutagenesis. Here, we describe the mechanism of this extraordinary mutator effect. We found that the mutation rate increased synergistically when the R696W mutation was combined with defects in Polδ proofreading or mismatch repair, indicating that pathways correcting DNA replication errors are not compromised in pol3-R696W mutants. DNA synthesis by purified Polδ-R696W was error-prone, but not to the extent that could account for the unprecedented mutator phenotype of pol3-R696W strains. In a search for cellular factors that augment the mutagenic potential of Polδ-R696W, we discovered that pol3-R696W causes S-phase checkpoint-dependent elevation of dNTP pools. Abrogating this elevation by strategic mutations in dNTP metabolism genes eliminated the mutator effect of pol3-R696W, whereas restoration of high intracellular dNTP levels restored the mutator phenotype. Further, the use of dNTP concentrations present in pol3-R696W cells for in vitro DNA synthesis greatly decreased the fidelity of Polδ-R696W and produced a mutation spectrum strikingly similar to the spectrum observed in vivo. The results support a model in which (i) faulty synthesis by Polδ-R696W leads to a checkpoint-dependent increase in dNTP levels and (ii) this increase mediates the hypermutator effect of Polδ-R696W by facilitating the extension of mismatched primer termini it creates and by promoting further errors that continue to fuel the mutagenic pathway.

  18. Mutation Spectrum of Common Deafness-Causing Genes in Patients with Non-Syndromic Deafness in the Xiamen Area, China.

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    Yi Jiang

    Full Text Available In China, approximately 30,000 babies are born with hearing impairment each year. However, the molecular factors causing congenital hearing impairment in the Xiamen area of Fujian province have not been evaluated. To provide accurate genetic testing and counseling in the Xiamen area, we investigated the molecular etiology of non-syndromic deafness in a deaf population from Xiamen. Unrelated students with hearing impairment (n = 155 who attended Xiamen Special Education School in Fujian Province were recruited for this study. Three common deafness-related genes, GJB2, SLC26A4, and mtDNA12SrRNA, were analyzed using all-exon sequencing. GJB2 mutations were detected in 27.1% (42/155 of the entire cohort. The non-syndromic hearing loss (NSHL hotspot mutations c.109G>A (p.V37I and c.235delC were found in this population, whereas the Caucasian hotspot mutation c.35delG was not. The allelic frequency of the c.109G>A mutation was 9.03% (28/310, slightly higher than that of c.235delC (8.39%, 26/310, which is the most common GJB2 mutation in most areas of China. The allelic frequency of the c.109G>A mutation was significantly higher in this Xiamen's deaf population than that in previously reported cohorts (P = 0.00. The SLC26A4 mutations were found in 16.77% (26/155 of this cohort. The most common pathogenic allele was c.IVS7-2A>G (6.13%, 19/310, and the second most common was the c.1079C>T (p.A360V mutation (1.94%, 6/310 which has rarely been reported as a hotspot mutation in other studies. The mutation rate of mtDNA12SrRNA in this group was 3.87% (6/155, all being the m.A1555G mutation. These findings show the specificity of the common deaf gene-mutation spectrum in this area. According to this study, there were specific hotspot mutations in Xiamen deaf patients. Comprehensive sequencing analysis of the three common deaf genes can help portray the mutation spectrum and develop optimal testing strategies for deaf patients in this area.

  19. Mutations in the MORC2 gene cause axonal Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Sevilla, Teresa; Lupo, Vincenzo; Martínez-Rubio, Dolores; Sancho, Paula; Sivera, Rafael; Chumillas, María J; García-Romero, Mar; Pascual-Pascual, Samuel I; Muelas, Nuria; Dopazo, Joaquín; Vílchez, Juan J; Palau, Francesc; Espinós, Carmen

    2016-01-01

    Charcot-Marie-Tooth disease (CMT) is a complex disorder with wide genetic heterogeneity. Here we present a new axonal Charcot-Marie-Tooth disease form, associated with the gene microrchidia family CW-type zinc finger 2 (MORC2). Whole-exome sequencing in a family with autosomal dominant segregation identified the novel MORC2 p.R190W change in four patients. Further mutational screening in our axonal Charcot-Marie-Tooth disease clinical series detected two additional sporadic cases, one patient who also carried the same MORC2 p.R190W mutation and another patient that harboured a MORC2 p.S25L mutation. Genetic and in silico studies strongly supported the pathogenicity of these sequence variants. The phenotype was variable and included patients with congenital or infantile onset, as well as others whose symptoms started in the second decade. The patients with early onset developed a spinal muscular atrophy-like picture, whereas in the later onset cases, the initial symptoms were cramps, distal weakness and sensory impairment. Weakness and atrophy progressed in a random and asymmetric fashion and involved limb girdle muscles, leading to a severe incapacity in adulthood. Sensory loss was always prominent and proportional to disease severity. Electrophysiological studies were consistent with an asymmetric axonal motor and sensory neuropathy, while fasciculations and myokymia were recorded rather frequently by needle electromyography. Sural nerve biopsy revealed pronounced multifocal depletion of myelinated fibres with some regenerative clusters and occasional small onion bulbs. Morc2 is expressed in both axons and Schwann cells of mouse peripheral nerve. Different roles in biological processes have been described for MORC2. As the silencing of Charcot-Marie-Tooth disease genes have been associated with DNA damage response, it is tempting to speculate that a deregulation of this pathway may be linked to the axonal degeneration observed in MORC2 neuropathy, thus adding a

  20. Mutation at the Evi1 locus in Junbo mice causes susceptibility to otitis media.

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    Nicholas Parkinson

    2006-10-01

    Full Text Available Otitis media (OM, inflammation of the middle ear, remains the most common cause of hearing impairment in children. It is also the most common cause of surgery in children in the developed world. There is evidence from studies of the human population and mouse models that there is a significant genetic component predisposing to OM, yet nothing is known about the underlying genetic pathways involved in humans. We identified an N-ethyl-N-nitrosourea-induced dominant mouse mutant Junbo with hearing loss due to chronic suppurative OM and otorrhea. This develops from acute OM that arises spontaneously in the postnatal period, with the age of onset and early severity dependent on the microbiological status of the mice and their air quality. We have identified the causal mutation, a missense change in the C-terminal zinc finger region of the transcription factor Evi1. This protein is expressed in middle ear basal epithelial cells, fibroblasts, and neutrophil leukocytes at postnatal day 13 and 21 when inflammatory changes are underway. The identification and characterization of the Junbo mutant elaborates a novel role for Evi1 in mammalian disease and implicates a new pathway in genetic predisposition to OM.

  1. EYS Mutations Causing Autosomal Recessive Retinitis Pigmentosa: Changes of Retinal Structure and Function with Disease Progression

    Directory of Open Access Journals (Sweden)

    David B. McGuigan

    2017-07-01

    Full Text Available Mutations in the EYS (eyes shut homolog gene are a common cause of autosomal recessive (ar retinitis pigmentosa (RP. Without a mammalian model of human EYS disease, there is limited understanding of details of disease expression and rates of progression of the retinal degeneration. We studied clinically and with chromatic static perimetry, spectral-domain optical coherence tomography (OCT, and en face autofluoresence imaging, a cohort of 15 patients (ages 12–51 at first visit, some of whom had longitudinal data of function and structure. Rod sensitivity was able to be measured by chromatic perimetry in most patients at their earliest visits and some patients retained patchy rod function into the fifth decade of life. As expected from RP, cone sensitivity persisted after rod function was no longer measurable. The photoreceptor nuclear layer of the central retina was abnormal except at the fovea in most patients at first visit. Perifoveal disease measured over a period of years indicated that photoreceptor structural loss was followed by dysmorphology of the inner retina and loss of retinal pigment epithelial integrity. Although there could be variability in severity, preliminary analyses of the rates of vision loss suggested that EYS is a more rapidly progressive disease than other ciliopathies causing arRP, such as USH2A and MAK.

  2. Gly369Cys mutation in mouse FGFR3 causes achondroplasia by affecting both chondrogenesis and osteogenesis

    Science.gov (United States)

    Chen, Lin; Adar, Rivka; Yang, Xiao; Monsonego, Efrat O.; Li, Cuiling; Hauschka, Peter V.; Yayon, Avner; Deng, Chu-Xia

    1999-01-01

    Missense mutations in fibroblast growth factor receptor 3 (FGFR3) result in several human skeletal dysplasias, including the most common form of dwarfism, achondroplasia. Here we show that a glycine-to-cysteine substitution at position 375 (Gly375Cys) in human FGFR3 causes ligand-independent dimerization and phosphorylation of FGFR3 and that the equivalent substitution at position 369 (Gly369Cys) in mouse FGFR3 causes dwarfism with features mimicking human achondroplasia. Accordingly, homozygous mice were more severely affected than heterozygotes. The resulting mutant mice exhibited macrocephaly and shortened limbs due to retarded endochondral bone growth and premature closure of cranial base synchondroses. Compared with their wild-type littermates, mutant mice growth plates shared an expanded resting zone and narrowed proliferating and hypertrophic zones, which is correlated with the activation of Stat proteins and upregulation of cell-cycle inhibitors. Reduced bone density is accompanied by increased activity of osteoclasts and upregulation of genes that are related to osteoblast differentiation, including osteopontin, osteonectin, and osteocalcin. These data reveal an essential role for FGF/FGFR3 signals in both chondrogenesis and osteogenesis during endochondral ossification. J. Clin. Invest. 104:1517–1525 (1999). PMID:10587515

  3. Bromodomain Inhibitors Correct Bioenergetic Deficiency Caused by Mitochondrial Disease Complex I Mutations.

    Science.gov (United States)

    Barrow, Joeva J; Balsa, Eduardo; Verdeguer, Francisco; Tavares, Clint D J; Soustek, Meghan S; Hollingsworth, Louis R; Jedrychowski, Mark; Vogel, Rutger; Paulo, Joao A; Smeitink, Jan; Gygi, Steve P; Doench, John; Root, David E; Puigserver, Pere

    2016-10-06

    Mitochondrial diseases comprise a heterogeneous group of genetically inherited disorders that cause failures in energetic and metabolic function. Boosting residual oxidative phosphorylation (OXPHOS) activity can partially correct these failures. Herein, using a high-throughput chemical screen, we identified the bromodomain inhibitor I-BET 525762A as one of the top hits that increases COX5a protein levels in complex I (CI) mutant cybrid cells. In parallel, bromodomain-containing protein 4 (BRD4), a target of I-BET 525762A, was identified using a genome-wide CRISPR screen to search for genes whose loss of function rescues death of CI-impaired cybrids grown under conditions requiring OXPHOS activity for survival. We show that I-BET525762A or loss of BRD4 remodeled the mitochondrial proteome to increase the levels and activity of OXPHOS protein complexes, leading to rescue of the bioenergetic defects and cell death caused by mutations or chemical inhibition of CI. These studies show that BRD4 inhibition may have therapeutic implications for the treatment of mitochondrial diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Novel FOXA2 mutation causes Hyperinsulinism, Hypopituitarism with Craniofacial and Endoderm-derived organ abnormalities.

    Science.gov (United States)

    Giri, Dinesh; Vignola, Maria Lillina; Gualtieri, Angelica; Scagliotti, Valeria; McNamara, Paul; Peak, Matthew; Didi, Mohammed; Gaston-Massuet, Carles; Senniappan, Senthil

    2017-11-15

    Congenital hypopituitarism (CH) is characterized by the deficiency of one or more pituitary hormones and can present alone or in association with complex disorders. Congenital hyperinsulinism (CHI) is a disorder of unregulated insulin secretion despite hypoglycaemia that can occur in isolation or as part of a wider syndrome. Molecular diagnosis is unknown in many cases of CH and CHI. The underlying genetic etiology causing the complex phenotype of CH and CHI is unknown. In this study, we identified a de novo heterozygous mutation in the developmental transcription factor, forkhead box A2, FOXA2 (c.505T>C, p.S169P) in a child with CHI and CH with craniofacial dysmorphic features, choroidal coloboma and endoderm-derived organ malformations in liver, lung and gastrointestinal tract by whole exome sequencing. The mutation is at a highly conserved residue within the DNA binding domain. We demonstrated strong expression of Foxa2 mRNA in the developing hypothalamus, pituitary, pancreas, lungs and oesophagus of mouse embryos using in situ hybridization. Expression profiling on human embryos by immunohistochemistry showed strong expression of hFOXA2 in the neural tube, third ventricle, diencephalon and pancreas. Transient transfection of HEK293T cells with Wt (Wild type) hFOXA2 or mutant hFOXA2 showed an impairment in transcriptional reporter activity by the mutant hFOXA2. Further analyses using western blot assays showed that the FOXA2 p.(S169P) variant is pathogenic resulting in lower expression levels when compared with Wt hFOXA2. Our results show, for the first time, the causative role of FOXA2 in a complex congenital syndrome with hypopituitarism, hyperinsulinism and endoderm-derived organ abnormalities. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Albinism-causing mutations in recombinant human tyrosinase alter intrinsic enzymatic activity.

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    Monika B Dolinska

    Full Text Available Tyrosinase (TYR catalyzes the rate-limiting, first step in melanin production and its gene (TYR is mutated in many cases of oculocutaneous albinism (OCA1, an autosomal recessive cause of childhood blindness. Patients with reduced TYR activity are classified as OCA1B; some OCA1B mutations are temperature-sensitive. Therapeutic research for OCA1 has been hampered, in part, by the absence of purified, active, recombinant wild-type and mutant human enzymes.The intra-melanosomal domain of human tyrosinase (residues 19-469 and two OCA1B related temperature-sensitive mutants, R422Q and R422W were expressed in insect cells and produced in T. ni larvae. The short trans-membrane fragment was deleted to avoid potential protein insolubility, while preserving all other functional features of the enzymes. Purified tyrosinase was obtained with a yield of >1 mg per 10 g of larval biomass. The protein was a monomeric glycoenzyme with maximum enzyme activity at 37°C and neutral pH. The two purified mutants when compared to the wild-type protein were less active and temperature sensitive. These differences are associated with conformational perturbations in secondary structure.The intramelanosomal domains of recombinant wild-type and mutant human tyrosinases are soluble monomeric glycoproteins with activities which mirror their in vivo function. This advance allows for the structure - function analyses of different mutant TYR proteins and correlation with their corresponding human phenotypes; it also provides an important tool to discover drugs that may improve tyrosinase activity and treat OCA1.

  6. Albinism-Causing Mutations in Recombinant Human Tyrosinase Alter Intrinsic Enzymatic Activity

    Science.gov (United States)

    Dolinska, Monika B.; Kovaleva, Elena; Backlund, Peter; Wingfield, Paul T.; Brooks, Brian P.; Sergeev, Yuri V.

    2014-01-01

    Background Tyrosinase (TYR) catalyzes the rate-limiting, first step in melanin production and its gene (TYR) is mutated in many cases of oculocutaneous albinism (OCA1), an autosomal recessive cause of childhood blindness. Patients with reduced TYR activity are classified as OCA1B; some OCA1B mutations are temperature-sensitive. Therapeutic research for OCA1 has been hampered, in part, by the absence of purified, active, recombinant wild-type and mutant human enzymes. Methodology/Principal Findings The intra-melanosomal domain of human tyrosinase (residues 19–469) and two OCA1B related temperature-sensitive mutants, R422Q and R422W were expressed in insect cells and produced in T. ni larvae. The short trans-membrane fragment was deleted to avoid potential protein insolubility, while preserving all other functional features of the enzymes. Purified tyrosinase was obtained with a yield of >1 mg per 10 g of larval biomass. The protein was a monomeric glycoenzyme with maximum enzyme activity at 37°C and neutral pH. The two purified mutants when compared to the wild-type protein were less active and temperature sensitive. These differences are associated with conformational perturbations in secondary structure. Conclusions/Significance The intramelanosomal domains of recombinant wild-type and mutant human tyrosinases are soluble monomeric glycoproteins with activities which mirror their in vivo function. This advance allows for the structure – function analyses of different mutant TYR proteins and correlation with their corresponding human phenotypes; it also provides an important tool to discover drugs that may improve tyrosinase activity and treat OCA1. PMID:24392141

  7. Missense mutations in the WD40 domain of AHI1 cause non-syndromic retinitis pigmentosa.

    Science.gov (United States)

    Nguyen, Thanh-Minh T; Hull, Sarah; Roepman, Ronald; van den Born, L Ingeborgh; Oud, Machteld M; de Vrieze, Erik; Hetterschijt, Lisette; Letteboer, Stef J F; van Beersum, Sylvia E C; Blokland, Ellen A; Yntema, Helger G; Cremers, Frans P M; van der Zwaag, Paul A; Arno, Gavin; van Wijk, Erwin; Webster, Andrew R; Haer-Wigman, Lonneke

    2017-09-01

    Recent findings suggesting that Abelson helper integration site 1 ( AHI1 ) is involved in non-syndromic retinal disease have been debated, as the functional significance of identified missense variants was uncertain. We assessed whether AHI1 variants cause non-syndromic retinitis pigmentosa (RP). Exome sequencing was performed in three probands with RP. The effects of the identified missense variants in AHI1 were predicted by three-dimensional structure homology modelling. Ciliary parameters were evaluated in patient's fibroblasts, and recombinant mutant proteins were expressed in ciliated retinal pigmented epithelium cells. In the three patients with RP, three sets of compound heterozygous variants were detected in AHI1 (c.2174G>A; p.Trp725* and c.2258A>T; p.Asp753Val, c.660delC; p.Ser221Glnfs*10 and c.2090C>T; p.Pro697Leu, c.2087A>G; p.His696Arg and c.2429C>T; p.Pro810Leu). All four missense variants were present in the conserved WD40 domain of Jouberin, the ciliary protein encoded by AHI1 , with variable predicted implications for the domain structure. No significant changes in the percentage of ciliated cells, nor in cilium length or intraflagellar transport were detected. However, expression of mutant recombinant Jouberin in ciliated cells showed a significantly decreased enrichment at the ciliary base. This report confirms that mutations in AHI1 can underlie autosomal recessive RP. Moreover, it structurally and functionally validates the effect of the RP-associated AHI1 variants on protein function, thus proposing a new genotype-phenotype correlation for AHI1 mutation associated retinal ciliopathies. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  8. Albinism-causing mutations in recombinant human tyrosinase alter intrinsic enzymatic activity.

    Science.gov (United States)

    Dolinska, Monika B; Kovaleva, Elena; Backlund, Peter; Wingfield, Paul T; Brooks, Brian P; Sergeev, Yuri V

    2014-01-01

    Tyrosinase (TYR) catalyzes the rate-limiting, first step in melanin production and its gene (TYR) is mutated in many cases of oculocutaneous albinism (OCA1), an autosomal recessive cause of childhood blindness. Patients with reduced TYR activity are classified as OCA1B; some OCA1B mutations are temperature-sensitive. Therapeutic research for OCA1 has been hampered, in part, by the absence of purified, active, recombinant wild-type and mutant human enzymes. The intra-melanosomal domain of human tyrosinase (residues 19-469) and two OCA1B related temperature-sensitive mutants, R422Q and R422W were expressed in insect cells and produced in T. ni larvae. The short trans-membrane fragment was deleted to avoid potential protein insolubility, while preserving all other functional features of the enzymes. Purified tyrosinase was obtained with a yield of >1 mg per 10 g of larval biomass. The protein was a monomeric glycoenzyme with maximum enzyme activity at 37°C and neutral pH. The two purified mutants when compared to the wild-type protein were less active and temperature sensitive. These differences are associated with conformational perturbations in secondary structure. The intramelanosomal domains of recombinant wild-type and mutant human tyrosinases are soluble monomeric glycoproteins with activities which mirror their in vivo function. This advance allows for the structure - function analyses of different mutant TYR proteins and correlation with their corresponding human phenotypes; it also provides an important tool to discover drugs that may improve tyrosinase activity and treat OCA1.

  9. A mutation in Nischarin causes otitis media via LIMK1 and NF-κB pathways

    Science.gov (United States)

    Purnell, Tom; Parker, Andrew; Ball, Greg; Gale, Richard; Williams, Debbie; Simon, Michelle M.; Mallon, Ann-Marie; Bhutta, Mahmood F.; Burton, Martin J.

    2017-01-01

    Otitis media (OM), inflammation of the middle ear (ME), is a common cause of conductive hearing impairment. Despite the importance of the disease, the aetiology of chronic and recurrent forms of middle ear inflammatory disease remains poorly understood. Studies of the human population suggest that there is a significant genetic component predisposing to the development of chronic OM, although the underlying genes are largely unknown. Using N-ethyl-N-nitrosourea mutagenesis we identified a recessive mouse mutant, edison, that spontaneously develops a conductive hearing loss due to chronic OM. The causal mutation was identified as a missense change, L972P, in the Nischarin (NISCH) gene. edison mice develop a serous or granulocytic effusion, increasingly macrophage and neutrophil rich with age, along with a thickened, inflamed mucoperiosteum. We also identified a second hypomorphic allele, V33A, with only modest increases in auditory thresholds and reduced incidence of OM. NISCH interacts with several proteins, including ITGA5 that is thought to have a role in modulating VEGF-induced angiogenesis and vascularization. We identified a significant genetic interaction between Nisch and Itga5; mice heterozygous for Itga5-null and homozygous for edison mutations display a significantly increased penetrance and severity of chronic OM. In order to understand the pathological mechanisms underlying the OM phenotype, we studied interacting partners to NISCH along with downstream signalling molecules in the middle ear epithelia of edison mouse. Our analysis implicates PAK1 and RAC1, and downstream signalling in LIMK1 and NF-κB pathways in the development of chronic OM. PMID:28806779

  10. Mutations in the Chromatin Regulator Gene BRPF1 Cause Syndromic Intellectual Disability and Deficient Histone Acetylation.

    Science.gov (United States)

    Yan, Kezhi; Rousseau, Justine; Littlejohn, Rebecca Okashah; Kiss, Courtney; Lehman, Anna; Rosenfeld, Jill A; Stumpel, Constance T R; Stegmann, Alexander P A; Robak, Laurie; Scaglia, Fernando; Nguyen, Thi Tuyet Mai; Fu, He; Ajeawung, Norbert F; Camurri, Maria Vittoria; Li, Lin; Gardham, Alice; Panis, Bianca; Almannai, Mohammed; Sacoto, Maria J Guillen; Baskin, Berivan; Ruivenkamp, Claudia; Xia, Fan; Bi, Weimin; Cho, Megan T; Potjer, Thomas P; Santen, Gijs W E; Parker, Michael J; Canham, Natalie; McKinnon, Margaret; Potocki, Lorraine; MacKenzie, Jennifer J; Roeder, Elizabeth R; Campeau, Philippe M; Yang, Xiang-Jiao

    2017-01-05

    Identification of over 500 epigenetic regulators in humans raises an interesting question regarding how chromatin dysregulation contributes to different diseases. Bromodomain and PHD finger-containing protein 1 (BRPF1) is a multivalent chromatin regulator possessing three histone-binding domains, one non-specific DNA-binding module, and several motifs for interacting with and activating three lysine acetyltransferases. Genetic analyses of fish brpf1 and mouse Brpf1 have uncovered an important role in skeletal, hematopoietic, and brain development, but it remains unclear how BRPF1 is linked to human development and disease. Here, we describe an intellectual disability disorder in ten individuals with inherited or de novo monoallelic BRPF1 mutations. Symptoms include infantile hypotonia, global developmental delay, intellectual disability, expressive language impairment, and facial dysmorphisms. Central nervous system and spinal abnormalities are also seen in some individuals. These clinical features overlap with but are not identical to those reported for persons with KAT6A or KAT6B mutations, suggesting that BRPF1 targets these two acetyltransferases and additional partners in humans. Functional assays showed that the resulting BRPF1 variants are pathogenic and impair acetylation of histone H3 at lysine 23, an abundant but poorly characterized epigenetic mark. We also found a similar deficiency in different lines of Brpf1-knockout mice. These data indicate that aberrations in the chromatin regulator gene BRPF1 cause histone H3 acetylation deficiency and a previously unrecognized intellectual disability syndrome. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  11. A mutation in Nischarin causes otitis media via LIMK1 and NF-κB pathways.

    Directory of Open Access Journals (Sweden)

    Michael Crompton

    2017-08-01

    Full Text Available Otitis media (OM, inflammation of the middle ear (ME, is a common cause of conductive hearing impairment. Despite the importance of the disease, the aetiology of chronic and recurrent forms of middle ear inflammatory disease remains poorly understood. Studies of the human population suggest that there is a significant genetic component predisposing to the development of chronic OM, although the underlying genes are largely unknown. Using N-ethyl-N-nitrosourea mutagenesis we identified a recessive mouse mutant, edison, that spontaneously develops a conductive hearing loss due to chronic OM. The causal mutation was identified as a missense change, L972P, in the Nischarin (NISCH gene. edison mice develop a serous or granulocytic effusion, increasingly macrophage and neutrophil rich with age, along with a thickened, inflamed mucoperiosteum. We also identified a second hypomorphic allele, V33A, with only modest increases in auditory thresholds and reduced incidence of OM. NISCH interacts with several proteins, including ITGA5 that is thought to have a role in modulating VEGF-induced angiogenesis and vascularization. We identified a significant genetic interaction between Nisch and Itga5; mice heterozygous for Itga5-null and homozygous for edison mutations display a significantly increased penetrance and severity of chronic OM. In order to understand the pathological mechanisms underlying the OM phenotype, we studied interacting partners to NISCH along with downstream signalling molecules in the middle ear epithelia of edison mouse. Our analysis implicates PAK1 and RAC1, and downstream signalling in LIMK1 and NF-κB pathways in the development of chronic OM.

  12. Biallelic SUN5 Mutations Cause Autosomal-Recessive Acephalic Spermatozoa Syndrome.

    Science.gov (United States)

    Zhu, Fuxi; Wang, Fengsong; Yang, Xiaoyu; Zhang, Jingjing; Wu, Huan; Zhang, Zhou; Zhang, Zhiguo; He, Xiaojin; Zhou, Ping; Wei, Zhaolian; Gecz, Jozef; Cao, Yunxia

    2016-10-06

    Acephalic spermatozoa syndrome is a rare and severe form of teratozoospermia characterized by a predominance of headless spermatozoa in the ejaculate. Family clustering and consanguinity suggest a genetic origin; however, causative mutations have yet to be identified. We performed whole-exome sequencing in two unrelated infertile men and subsequent variant filtering identified one homozygous (c.824C>T [p.Thr275Met]) and one compound heterozygous (c.1006C>T [p.Arg356Cys] and c.485T>A [p.Met162Lys]) SUN5 (also named TSARG4) variants. Sanger sequencing of SUN5 in 15 additional unrelated infertile men revealed four compound heterozygous (c.381delA [p.Val128Serfs ∗ 7] and c.824C>T [p.Thr275Met]; c.381delA [p.Val128Serfs ∗ 7] and c.781G>A [p.Val261Met]; c.216G>A [p.Trp72 ∗ ] and c.1043A>T [p.Asn348Ile]; c.425+1G>A/c.1043A>T [p.Asn348Ile]) and two homozygous (c.851C>G [p.Ser284 ∗ ]; c.350G>A [p.Gly114Arg]) variants in six individuals. These 10 SUN5 variants were found in 8 of 17 unrelated men, explaining the genetic defect in 47.06% of the affected individuals in our cohort. These variants were absent in 100 fertile population-matched control individuals. SUN5 variants lead to absent, significantly reduced, or truncated SUN5, and certain variants altered SUN5 distribution in the head-tail junction of the sperm. In summary, these results demonstrate that biallelic SUN5 mutations cause male infertility due to autosomal-recessive acephalic spermatozoa syndrome. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    Wang, Shih-Kai; Chan, Hui-Chen; Makovey, Igor; Simmer, James P; Hu, Jan C-C

    2012-01-01

    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.

  14. SLC1A4 mutations cause a novel disorder of intellectual disability, progressive microcephaly, spasticity and thin corpus callosum.

    Science.gov (United States)

    Heimer, G; Marek-Yagel, D; Eyal, E; Barel, O; Oz Levi, D; Hoffmann, C; Ruzzo, E K; Ganelin-Cohen, E; Lancet, D; Pras, E; Rechavi, G; Nissenkorn, A; Anikster, Y; Goldstein, D B; Ben Zeev, B

    2015-10-01

    Two unrelated patients, presenting with significant global developmental delay, severe progressive microcephaly, seizures, spasticity and thin corpus callosum (CC) underwent trio whole-exome sequencing. No candidate variant was found in any known genes related to the phenotype. However, crossing the data of the patients illustrated that they both manifested pathogenic variants in the SLC1A4 gene which codes the ASCT1 transporter of serine and other neutral amino acids. The Ashkenazi patient is homozygous for a deleterious missense c.766G>A, p.(E256K) mutation whereas the Ashkenazi-Iraqi patient is compound heterozygous for this mutation and a nonsense c.945delTT, p.(Leu315Hisfs*42) mutation. Structural prediction demonstrates truncation of significant portion of the protein by the nonsense mutation and speculates functional disruption by the missense mutation. Both mutations are extremely rare in general population databases, however, the missense mutation was found in heterozygous mode in 1:100 Jewish Ashkenazi controls suggesting a higher carrier rate among Ashkenazi Jews. We conclude that SLC1A4 is the disease causing gene of a novel neurologic disorder manifesting with significant intellectual disability, severe postnatal microcephaly, spasticity and thin CC. The role of SLC1A4 in the serine transport from astrocytes to neurons suggests a possible pathomechanism for this disease and implies a potential therapeutic approach. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. De novo heterozygous mutations in SMC3 cause a range of Cornelia de Lange syndrome-overlapping phenotypes.

    Science.gov (United States)

    Gil-Rodríguez, María Concepción; Deardorff, Matthew A; Ansari, Morad; Tan, Christopher A; Parenti, Ilaria; Baquero-Montoya, Carolina; Ousager, Lilian B; Puisac, Beatriz; Hernández-Marcos, María; Teresa-Rodrigo, María Esperanza; Marcos-Alcalde, Iñigo; Wesselink, Jan-Jaap; Lusa-Bernal, Silvia; Bijlsma, Emilia K; Braunholz, Diana; Bueno-Martinez, Inés; Clark, Dinah; Cooper, Nicola S; Curry, Cynthia J; Fisher, Richard; Fryer, Alan; Ganesh, Jaya; Gervasini, Cristina; Gillessen-Kaesbach, Gabriele; Guo, Yiran; Hakonarson, Hakon; Hopkin, Robert J; Kaur, Maninder; Keating, Brendan J; Kibaek, María; Kinning, Esther; Kleefstra, Tjitske; Kline, Antonie D; Kuchinskaya, Ekaterina; Larizza, Lidia; Li, Yun R; Liu, Xuanzhu; Mariani, Milena; Picker, Jonathan D; Pié, Ángeles; Pozojevic, Jelena; Queralt, Ethel; Richer, Julie; Roeder, Elizabeth; Sinha, Anubha; Scott, Richard H; So, Joyce; Wusik, Katherine A; Wilson, Louise; Zhang, Jianguo; Gómez-Puertas, Paulino; Casale, César H; Ström, Lena; Selicorni, Angelo; Ramos, Feliciano J; Jackson, Laird G; Krantz, Ian D; Das, Soma; Hennekam, Raoul C M; Kaiser, Frank J; FitzPatrick, David R; Pié, Juan

    2015-04-01

    Cornelia de Lange syndrome (CdLS) is characterized by facial dysmorphism, growth failure, intellectual disability, limb malformations, and multiple organ involvement. Mutations in five genes, encoding subunits of the cohesin complex (SMC1A, SMC3, RAD21) and its regulators (NIPBL, HDAC8), account for at least 70% of patients with CdLS or CdLS-like phenotypes. To date, only the clinical features from a single CdLS patient with SMC3 mutation has been published. Here, we report the efforts of an international research and clinical collaboration to provide clinical comparison of 16 patients with CdLS-like features caused by mutations in SMC3. Modeling of the mutation effects on protein structure suggests a dominant-negative effect on the multimeric cohesin complex. When compared with typical CdLS, many SMC3-associated phenotypes are also characterized by postnatal microcephaly but with a less distinctive craniofacial appearance, a milder prenatal growth retardation that worsens in childhood, few congenital heart defects, and an absence of limb deficiencies. While most mutations are unique, two unrelated affected individuals shared the same mutation but presented with different phenotypes. This work confirms that de novo SMC3 mutations account for ∼ 1%-2% of CdLS-like phenotypes. © 2015 WILEY PERIODICALS, INC.

  16. Mapping and exome sequencing identifies a mutation in the IARS gene as the cause of hereditary perinatal weak calf syndrome.

    Science.gov (United States)

    Hirano, Takashi; Kobayashi, Naohiko; Matsuhashi, Tamako; Watanabe, Daisaku; Watanabe, Toshio; Takasuga, Akiko; Sugimoto, Mayumi; Sugimoto, Yoshikazu

    2013-01-01

    We identified an IARS (isoleucyl-tRNA synthetase) c.235G>C (p.Val79Leu) substitution as the causative mutation for neonatal weakness with intrauterine growth retardation (perinatal weak calf syndrome). In Japanese Black cattle, the syndrome was frequently found in calves sired by Bull A. Hence, we employed homozygosity mapping and linkage analysis. In order to identify the perinatal weak calf syndrome locus in a 4.04-Mb region of BTA 8, we analysed a paternal half-sibling family with a BovineSNP50 BeadChip and microsatellites. In this critical region, we performed exome sequencing to identify a causative mutation. Three variants were detected as possible candidates for causative mutations that were predicted to disrupt the protein function, including a G>C (p.Val79Leu) mutation in IARS c.235. The IARS c.235G>C mutation was not a homozygous risk allele in the 36 healthy offspring of Bull A. Moreover, the IARS Val79 residue and its flanking regions were evolutionarily and highly conserved. The IARS mutant (Leu79) had decreased aminoacylation activity. Additionally, the homozygous mutation was not found in any of 1526 healthy cattle. Therefore, we concluded that the IARS c.235G>C mutation was the cause of hereditary perinatal weak calf syndrome.

  17. Identification of FASTKD2 compound heterozygous mutations as the underlying cause of autosomal recessive MELAS-like syndrome.

    Science.gov (United States)

    Yoo, Da Hye; Choi, Young-Chul; Nam, Da Eun; Choi, Sun Seong; Kim, Ji Won; Choi, Byung-Ok; Chung, Ki Wha

    2017-07-01

    Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a condition that affects many parts of the body, particularly the brain and muscles. This study examined a Korean MELAS-like syndrome patient with seizure, stroke-like episode, and optic atrophy. Target sequencing of whole mtDNA and 73 nuclear genes identified compound heterozygous mutations p.R205X and p.L255P in the FASTKD2. Each of his unaffected parents has one of the two mutations, and both mutations were not found in 302 controls. FASTKD2 encodes a FAS-activated serine-threonine (FAST) kinase domain 2 which locates in the mitochondrial inner compartment. A FASTKD2 nonsense mutation was once reported as the cause of a recessive infantile mitochondrial encephalomyopathy. The present case showed relatively mild symptoms with a late onset age, compared to a previous patient with FASTKD2 mutation, implicating an inter-allelic clinical heterogeneity. Because this study is the second report of an autosomal recessive mitochondrial encephalomyopathy patient with a FASTKD2 mutation, it will extend the phenotypic spectrum of the FASTKD2 mutation. Copyright © 2017. Published by Elsevier B.V.

  18. Exonization of an Intronic LINE-1 Element Causing Becker Muscular Dystrophy as a Novel Mutational Mechanism in Dystrophin Gene.

    Science.gov (United States)

    Gonçalves, Ana; Oliveira, Jorge; Coelho, Teresa; Taipa, Ricardo; Melo-Pires, Manuel; Sousa, Mário; Santos, Rosário

    2017-10-03

    A broad mutational spectrum in the dystrophin ( DMD ) gene, from large deletions/duplications to point mutations, causes Duchenne/Becker muscular dystrophy (D/BMD). Comprehensive genotyping is particularly relevant considering the mutation-centered therapies for dystrophinopathies. We report the genetic characterization of a patient with disease onset at age 13 years, elevated creatine kinase levels and reduced dystrophin labeling, where multiplex-ligation probe amplification (MLPA) and genomic sequencing failed to detect pathogenic variants. Bioinformatic, transcriptomic (real time PCR, RT-PCR), and genomic approaches (Southern blot, long-range PCR, and single molecule real-time sequencing) were used to characterize the mutation. An aberrant transcript was identified, containing a 103-nucleotide insertion between exons 51 and 52, with no similarity with the DMD gene. This corresponded to the partial exonization of a long interspersed nuclear element (LINE-1), disrupting the open reading frame. Further characterization identified a complete LINE-1 (~6 kb with typical hallmarks) deeply inserted in intron 51. Haplotyping and segregation analysis demonstrated that the mutation had a de novo origin. Besides underscoring the importance of mRNA studies in genetically unsolved cases, this is the first report of a disease-causing fully intronic LINE-1 element in DMD , adding to the diversity of mutational events that give rise to D/BMD.

  19. Genotype–phenotype characteristics and baseline natural history of heritable neuropathies caused by mutations in the MPZ gene

    Science.gov (United States)

    Feely, Shawna; Scherer, Steven S.; Herrmann, David N.; Burns, Joshua; Muntoni, Francesco; Li, Jun; Siskind, Carly E.; Day, John W.; Laura, Matilde; Sumner, Charlotte J.; Lloyd, Thomas E.; Ramchandren, Sindhu; Shy, Rosemary R.; Grider, Tiffany; Bacon, Chelsea; Finkel, Richard S.; Yum, Sabrina W.; Moroni, Isabella; Piscosquito, Giuseppe; Pareyson, Davide; Reilly, Mary M.; Shy, Michael E.

    2015-01-01

    We aimed to characterize genotype–phenotype correlations and establish baseline clinical data for peripheral neuropathies caused by mutations in the myelin protein zero (MPZ) gene. MPZ mutations are the second leading cause of Charcot–Marie–Tooth disease type 1. Recent research makes clinical trials for patients with MPZ mutations a realistic possibility. However, the clinical severity varies with different mutations and natural history data on progression is sparse. We present cross-sectional data to begin to define the phenotypic spectrum and clinical baseline of patients with these mutations. A cohort of patients with MPZ gene mutations was identified in 13 centres of the Inherited Neuropathies Consortium - Rare Disease Clinical Research Consortium (INC-RDCRC) between 2009 and 2012 and at Wayne State University between 1996 and 2009. Patient phenotypes were quantified by the Charcot–Marie–Tooth disease neuropathy score version 1 or 2 and the Charcot–Marie–Tooth disease paediatric scale outcome instruments. Genetic testing was performed in all patients and/or in first- or second-degree relatives to document mutation in MPZ gene indicating diagnosis of Charcot–Marie–Tooth disease type 1B. There were 103 patients from 71 families with 47 different MPZ mutations with a mean age of 40 years (range 3–84 years). Patients and mutations were separated into infantile, childhood and adult-onset groups. The infantile onset group had higher Charcot–Marie–Tooth disease neuropathy score version 1 or 2 and slower nerve conductions than the other groups, and severity increased with age. Twenty-three patients had no family history of Charcot–Marie–Tooth disease. Sixty-one patients wore foot/ankle orthoses, 19 required walking assistance or support, and 10 required wheelchairs. There was hearing loss in 21 and scoliosis in 17. Forty-two patients did not begin walking until after 15 months of age. Half of the infantile onset patients then required

  20. XLID-Causing Mutations and Associated Genes Challenged in Light of Data From Large-Scale Human Exome Sequencing

    OpenAIRE

    Piton, Amélie; Redin, Claire; Mandel, Jean-Louis

    2013-01-01

    Because of the unbalanced sex ratio (1.3–1.4 to 1) observed in intellectual disability (ID) and the identification of large ID-affected families showing X-linked segregation, much attention has been focused on the genetics of X-linked ID (XLID). Mutations causing monogenic XLID have now been reported in over 100 genes, most of which are commonly included in XLID diagnostic gene panels. Nonetheless, the boundary between true mutations and rare non-disease-causing variants often remains elusive...

  1. A synonymous mutation in TCOF1 causes Treacher Collins syndrome due to mis-splicing of a constitutive exon.

    Science.gov (United States)

    Macaya, D; Katsanis, S H; Hefferon, T W; Audlin, S; Mendelsohn, N J; Roggenbuck, J; Cutting, G R

    2009-08-01

    Interpretation of the pathogenicity of sequence alterations in disease-associated genes is challenging. This is especially true for novel alterations that lack obvious functional consequences. We report here on a patient with Treacher Collins syndrome (TCS) found to carry a previously reported mutation, c.122C > T, which predicts p.A41V, and a novel synonymous mutation, c.3612A > C. Pedigree analysis showed that the c.122C > T mutation segregated with normal phenotypes in multiple family members while the c.3612A > C was de novo in the patient. Analysis of TCOF1 RNA in lymphocytes showed a transcript missing exon 22. These results show that TCS in the patient is due to haploinsufficiency of TCOF1 caused by the synonymous de novo c.3612A > C mutation. This study highlights the importance of clinical and pedigree evaluation in the interpretation of known and novel sequence alterations. 2009 Wiley-Liss, Inc.

  2. A new mutation in the gene encoding mitochondrial seryl-tRNA synthetase as a cause of HUPRA syndrome.

    Science.gov (United States)

    Rivera, Henry; Martín-Hernández, Elena; Delmiro, Aitor; García-Silva, María Teresa; Quijada-Fraile, Pilar; Muley, Rafael; Arenas, Joaquín; Martín, Miguel A; Martínez-Azorín, Francisco

    2013-09-13

    HUPRA syndrome is a rare mitochondrial disease characterized by hyperuricemia, pulmonary hypertension, renal failure in infancy and alkalosis. This syndrome was previously described in three patients with a homozygous mutation c.1169A > G (p.D390G) in SARS2, encoding the mitochondrial seryl-tRNA synthetase. Here we report the clinical and genetic findings in a girl and her brother. Both patients were clinically diagnosed with the HUPRA syndrome. Analysis of the pedigree identified a new homozygous mutation c.1205G > A (p.R402H) in SARS2 gene. This mutation is very rare in the population and it is located at the C-terminal globular domain of the homodimeric enzyme very close to p.D390G. Several data support that p.R402H mutation in SARS2 is a new cause of HUPRA syndrome.

  3. NBAS mutations cause acute liver failure: when acetaminophen is not a culprit.

    Science.gov (United States)

    Calvo, Pier Luigi; Tandoi, Francesco; Haak, Tobias B; Brunati, Andrea; Pinon, Michele; Olio, Dominic Dell; Romagnoli, Renato; Spada, Marco

    2017-09-25

    Pediatric acute-liver-failure due to acetaminophen (APAP) administration at therapeutic dosage is rare, while viral infections and metabolic defects are the prevalent causes. Yet, as acetaminophen is routinely used in febrile illnesses, it may be mistakenly held responsible for the acute liver damage. An 11 month old boy had been on acetaminophen for 10 days (total dose 720 mg = 72 mg/kg) when he developed acute-liver-failure with encephalopathy. As he rapidly improved on N-acetylcysteine (NAC) infusion, it was concluded that chronic acetaminophen administration in an infant had lead to acute-liver-failure even at therapeutic doses, that N-acetylcysteine infusion had been life-saving and should be immediately started in similar circumstances. The child, however, had two further episodes of acute liver damage over a 34-month period, without having been given acetaminophen, as the parents carefully avoided using it. His clinical, laboratory and radiological findings between the acute episodes were unremarkable. His features and skeletal surveys were not suggestive of a syndromic condition. He then went on to suffer another episode of acute-liver-failure with multi-organ failure, necessitating an urgent liver transplant. All efforts to come to a diagnosis for the causes of his recurrent episodes of liver failure had been unsuccessful, until a biallelic mutation in the NBAS gene was reported to be associated with recurrent acute-liver-failure in children. The boy's DNA analysis revealed compound heterozygous pathogenic mutations in the NBAS gene. Liver failure episodes in these patients are triggered and worsened by fever, most likely due to thermal susceptibility of hepatocytes, hence APAP, rather than being a culprit, is part of the supportive treatment. We suggest that, in acute-liver-failure with a history of acetaminophen exposure at therapeutic dosage, clinicians should not be contented with administering NAC, but should consider an alternative etiology

  4. [A de novo mutation of P gene causes oculocutaneous albinism type 2 with prenatal diagnosis].

    Science.gov (United States)

    Zhang, Liyun; Xu, Bei; Zhong, Yanfang; Chen, Xiaofei; Zheng, Hui; Jiang, Weiying; Li, Hongyi

    2013-06-01

    To determine the genotype of a family affected with oculocutaneous albinism (OCA) and to provide genetic counseling and prenatal diagnosis. To determine the genotypes and mutational sites through PCR and sequencing for all exons and exon-intron junctions of 4 OCA genes in the proband and the P gene of her parents. Prenatal genotyping of the fetus was carried out using amniocentesis sample. The patient was diagnosed with OCA2 based on a genotype of c.1327G>A/c.2360C>T. Her father was heterozygous for c.2360C> T, whilst her mother has none of the two mutations. c.1327G>A is therefore a maternal de novo mutation. Neither of the mutations was found in the fetus. A maternally inherited de novo mutation c.1327G>A has been identified in the patient. In order to detect de novo mutations, full sequence analysis is necessary.

  5. High Frequency of Pulmonary Hypertension-Causing Gene Mutation in Chinese Patients with Chronic Thromboembolic Pulmonary Hypertension.

    Directory of Open Access Journals (Sweden)

    Qunying Xi

    Full Text Available The pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH is unknown. Histopathologic studies revealed that pulmonary vasculature lesions similar to idiopathic pulmonary arterial hypertension (PAH existed in CTEPH patients as well. It's well-known that genetic predisposition plays an important role in the mechanism of PAH. So we hypothesized that PAH-causing gene mutation might exist in some CTEPH patients and act as a background to facilitate the development of CTEPH. In this study, we analyzed 7 PAH-causing genes including BMPR2, ACVRL1, ENG, SMAD9, CAV1, KCNK3, and CBLN2 in 49 CTEPH patients and 17 patients recovered from pulmonary embolism (PE but without pulmonary hypertension(PH. The results showed that the nonsynonymous mutation rate in CTEPH patients is significantly higher than that in PE without PH patients (25 out of 49 (51% CTEPH patients vs. 3 out of 17 PE without PH patients (18%; p = 0.022. Four CTEPH patients had the same point mutation in ACVRL1 exon 10 (c.1450C>G, a mutation approved to be associated with PH in a previous study. In addition, we identified two CTEPH associated SNPs (rs3739817 and rs55805125. Our results suggest that PAH-causing gene mutation might play an important role in the development of CTEPH.

  6. Mild and severe muscular dystrophy caused by a single {gamma}-sarcoglycan mutation

    Energy Technology Data Exchange (ETDEWEB)

    McNally, E.M.; Boennemann, C.G.; Lidov, H.G.W. [Brigham and Women`s Hospital, Boston, MA (United States)] [and others

    1996-11-01

    Autosomal recessive muscular dystrophy is genetically heterogeneous. One form of this disorder, limb-girdle muscular dystrophy type 2C (LGMD 2C), is prevalent in northern Africa and has been shown to be associated with a single mutation in the gene encoding the dystrophin-associated protein {gamma}-sarcoglycan. The previous mutation analysis of {gamma}-sarcoglycan required the availability of muscle biopsies. To establish a mutation assay for genomic DNA, the intron-exon structure of the {gamma}-sarcoglycan gene was determined, and primers were designed to amplify each of the exons encoding {gamma}-sarcoglycan. We studied a group of Brazilian muscular dystrophy patients for mutations in the {gamma}-sarcoglycan gene. These patients were selected on the basis of autosomal inheritance and/or the presence of normal dystrophin and/or deficiency of {alpha}-sarcoglycan immunostaining. Four of 19 patients surveyed had a single, homozygous mutation in the {gamma}-sarcoglycan gene. The mutation identified in these patients, all of African-Brazilian descent, is identical to that seen in the North African population, suggesting that even patients of remote African descent may carry this mutation. The phenotype in these patients varied considerably. Of four families with an identical mutation, three have a severe Duchenne-like muscular dystrophy. However, one family has much milder symptoms, suggesting that other loci may be present that modify the severity of the clinical course resulting from {gamma}-sarcoglycan gene mutations. 19 refs., 5 figs., 3 tabs.

  7. The myopathy-causing mutation DNM2-S619L leads to defective tubulation in vitro and in developing zebrafish

    Directory of Open Access Journals (Sweden)

    Elizabeth M. Gibbs

    2014-01-01

    Full Text Available DNM2 is a ubiquitously expressed GTPase that regulates multiple subcellular processes. Mutations in DNM2 are a common cause of centronuclear myopathy, a severe disorder characterized by altered skeletal muscle structure and function. The precise mechanisms underlying disease-associated DNM2 mutations are unresolved. We examined the common DNM2-S619L mutation using both in vitro and in vivo approaches. Expression of DNM2-S619L in zebrafish led to the accumulation of aberrant vesicular structures and to defective excitation-contraction coupling. Expression of DNM2-S619L in COS7 cells resulted in defective BIN1-dependent tubule formation. These data suggest that DNM2-S619L causes disease, in part, by interfering with membrane tubulation.

  8. Audiometric characteristics of a dutch family with a new mutation in GATA3 causing HDR syndrome.

    Science.gov (United States)

    van Beelen, E; Leijendeckers, J M; Admiraal, R J C; Huygen, P L M; Hoefsloot, L H; Pennings, R J E; Snik, A F M; Kunst, H P M

    2014-01-01

    We present the case of a Dutch family with a new mutation (c523_528dup) in GATA3 causing HDR syndrome. HDR syndrome is characterised by hypoparathyroidism, deafness and renal defects. In this study, we describe the audiometric characteristics of 5 patients from this family. Their hearing impairment was congenital, bilateral and symmetric. Audiograms showed mild-to-moderate hearing impairment with a flat audiogram configuration. Higher frequencies tended to be affected more strongly. Cross-sectional analyses showed no progression, and a mean audiogram was established. Psychophysical measurements in 3 HDR patients - including speech reception in noise, loudness scaling, gap detection and difference limen for frequency - were obtained to assess hearing function in greater detail. Overall, the results of the psychophysical measurements indicated characteristics of outer hair cell loss. CT scanning showed no anomalies in 3 of the HDR patients. Although 2 patients displayed vestibular symptoms, no anomalies in the vestibular system were found by vestibulo-ocular examination. Our results are in agreement with the theory that outer hair cell malfunctioning can play a major role in HDR syndrome.

  9. Mutations in DDX58, which Encodes RIG-I, Cause Atypical Singleton-Merten Syndrome

    Science.gov (United States)

    Jang, Mi-Ae; Kim, Eun Kyoung; Now, Hesung; Nguyen, Nhung T.H.; Kim, Woo-Jong; Yoo, Joo-Yeon; Lee, Jinhyuk; Jeong, Yun-Mi; Kim, Cheol-Hee; Kim, Ok-Hwa; Sohn, Seongsoo; Nam, Seong-Hyeuk; Hong, Yoojin; Lee, Yong Seok; Chang, Sung-A; Jang, Shin Yi; Kim, Jong-Won; Lee, Myung-Shik; Lim, So Young; Sung, Ki-Sun; Park, Ki-Tae; Kim, Byoung Joon; Lee, Joo-Heung; Kim, Duk-Kyung; Kee, Changwon; Ki, Chang-Seok

    2015-01-01

    Singleton-Merten syndrome (SMS) is an autosomal-dominant multi-system disorder characterized by dental dysplasia, aortic calcification, skeletal abnormalities, glaucoma, psoriasis, and other conditions. Despite an apparent autosomal-dominant pattern of inheritance, the genetic background of SMS and information about its phenotypic heterogeneity remain unknown. Recently, we found a family affected by glaucoma, aortic calcification, and skeletal abnormalities. Unlike subjects with classic SMS, affected individuals showed normal dentition, suggesting atypical SMS. To identify genetic causes of the disease, we performed exome sequencing in this family and identified a variant (c.1118A>C [p.Glu373Ala]) of DDX58, whose protein product is also known as RIG-I. Further analysis of DDX58 in 100 individuals with congenital glaucoma identified another variant (c.803G>T [p.Cys268Phe]) in a family who harbored neither dental anomalies nor aortic calcification but who suffered from glaucoma and skeletal abnormalities. Cys268 and Glu373 residues of DDX58 belong to ATP-binding motifs I and II, respectively, and these residues are predicted to be located closer to the ADP and RNA molecules than other nonpathogenic missense variants by protein structure analysis. Functional assays revealed that DDX58 alterations confer constitutive activation and thus lead to increased interferon (IFN) activity and IFN-stimulated gene expression. In addition, when we transduced primary human trabecular meshwork cells with c.803G>T (p.Cys268Phe) and c.1118A>C (p.Glu373Ala) mutants, cytopathic effects and a significant decrease in cell number were observed. Taken together, our results demonstrate that DDX58 mutations cause atypical SMS manifesting with variable expression of glaucoma, aortic calcification, and skeletal abnormalities without dental anomalies. PMID:25620203

  10. A Mutation in LTBP2 Causes Congenital Glaucoma in Domestic Cats (Felis catus).

    Science.gov (United States)

    Kuehn, Markus H; Lipsett, Koren A; Menotti-Raymond, Marilyn; Whitmore, S Scott; Scheetz, Todd E; David, Victor A; O'Brien, Stephen J; Zhao, Zhongyuan; Jens, Jackie K; Snella, Elizabeth M; Ellinwood, N Matthew; McLellan, Gillian J

    2016-01-01

    The glaucomas are a group of diseases characterized by optic nerve damage that together represent a leading cause of blindness in the human population and in domestic animals. Here we report a mutation in LTBP2 that causes primary congenital glaucoma (PCG) in domestic cats. We identified a spontaneous form of PCG in cats and established a breeding colony segregating for PCG consistent with fully penetrant, autosomal recessive inheritance of the trait. Elevated intraocular pressure, globe enlargement and elongated ciliary processes were consistently observed in all affected cats by 8 weeks of age. Varying degrees of optic nerve damage resulted by 6 months of age. Although subtle lens zonular instability was a common feature in this cohort, pronounced ectopia lentis was identified in less than 10% of cats examined. Thus, glaucoma in this pedigree is attributed to histologically confirmed arrest in the early post-natal development of the aqueous humor outflow pathways in the anterior segment of the eyes of affected animals. Using a candidate gene approach, significant linkage was established on cat chromosome B3 (LOD 18.38, θ = 0.00) using tightly linked short tandem repeat (STR) loci to the candidate gene, LTBP2. A 4 base-pair insertion was identified in exon 8 of LTBP2 in affected individuals that generates a frame shift that completely alters the downstream open reading frame and eliminates functional domains. Thus, we describe the first spontaneous and highly penetrant non-rodent model of PCG identifying a valuable animal model for primary glaucoma that closely resembles the human disease, providing valuable insights into mechanisms underlying the disease and a valuable animal model for testing therapies.

  11. A small indel mutation in an anthocyanin transporter causes variegated colouration of peach flowers.

    Science.gov (United States)

    Cheng, Jun; Liao, Liao; Zhou, Hui; Gu, Chao; Wang, Lu; Han, Yuepeng

    2015-12-01

    The ornamental peach cultivar 'Hongbaihuatao (HBH)' can simultaneously bear pink, red, and variegated flowers on a single tree. Anthocyanin content in pink flowers is extremely low, being only 10% that of a red flower. Surprisingly, the expression of anthocyanin structural and potential regulatory genes in white flowers was not significantly lower than that in both pink and red flowers. However, proteomic analysis revealed a GST encoded by a gene-regulator involved in anthocyanin transport (Riant)-which is expressed in the red flower, but almost undetectable in the variegated flower. The Riant gene contains an insertion-deletion (indel) polymorphism in exon 3. In white flowers, the Riant gene is interrupted by a 2-bp insertion in the last exon, which causes a frameshift and a premature stop codon. In contrast, both pink and red flowers that arise from bud sports are heterozygous for the Riant locus, with one functional allele due to the 2-bp deletion or a novel 1-bp insertion. Southern blot analysis indicated that the Riant gene occurs in a single copy in the peach genome and it is not interrupted by a transposon. The function of the Riant gene was confirmed by its ectopic expression in the Arabidopsis tt19 mutant, where it complements the anthocyanin phenotype, but not the proanthocyanidin pigmentation in seed coat. Collectively,these results indicate that a small indel mutation in the Riant gene, which is not the result of a transposon insertion or excision, causes variegated colouration of peach flowers. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. A Mutation in LTBP2 Causes Congenital Glaucoma in Domestic Cats (Felis catus.

    Directory of Open Access Journals (Sweden)

    Markus H Kuehn

    Full Text Available The glaucomas are a group of diseases characterized by optic nerve damage that together represent a leading cause of blindness in the human population and in domestic animals. Here we report a mutation in LTBP2 that causes primary congenital glaucoma (PCG in domestic cats. We identified a spontaneous form of PCG in cats and established a breeding colony segregating for PCG consistent with fully penetrant, autosomal recessive inheritance of the trait. Elevated intraocular pressure, globe enlargement and elongated ciliary processes were consistently observed in all affected cats by 8 weeks of age. Varying degrees of optic nerve damage resulted by 6 months of age. Although subtle lens zonular instability was a common feature in this cohort, pronounced ectopia lentis was identified in less than 10% of cats examined. Thus, glaucoma in this pedigree is attributed to histologically confirmed arrest in the early post-natal development of the aqueous humor outflow pathways in the anterior segment of the eyes of affected animals. Using a candidate gene approach, significant linkage was established on cat chromosome B3 (LOD 18.38, θ = 0.00 using tightly linked short tandem repeat (STR loci to the candidate gene, LTBP2. A 4 base-pair insertion was identified in exon 8 of LTBP2 in affected individuals that generates a frame shift that completely alters the downstream open reading frame and eliminates functional domains. Thus, we describe the first spontaneous and highly penetrant non-rodent model of PCG identifying a valuable animal model for primary glaucoma that closely resembles the human disease, providing valuable insights into mechanisms underlying the disease and a valuable animal model for testing therapies.

  13. Homozygous indel mutation in CDH11 as the probable cause of Elsahy-Waters syndrome.

    Science.gov (United States)

    Taskiran, Ekim Z; Karaosmanoglu, Beren; Koşukcu, Can; Doğan, Özlem A; Taylan-Şekeroğlu, Hande; Şimşek-Kiper, Pelin Ö; Utine, Eda G; Boduroğlu, Koray; Alikaşifoğlu, Mehmet

    2017-12-01

    Two sisters from a consanguineous couple were seen in genetics department for facial dysmorphic features and glaucoma. They both had broad foreheads, hypertelorism, megalocorneas, thick eyebrows with synophrys, flat malar regions, broad and bulbous noses, and mild prognathism. Both had glaucoma, younger one also had cataracts and phthisis bulbi. Other findings included bilateral partial cutaneous syndactyly of 2nd and 3rd fingers, history of impacted teeth with dentigerous cyst in the elder one, and intellectual disability (mild and borderline). The sisters were considered to have Elsahy-Waters syndrome. In order to elucidate the underlying molecular cause, sisters and their healthy parents were genotyped by SNP arrays, followed by homozygosity mapping. Homozygous regions were further analyzed by exome sequencing in one affected individual. A homozygous indel variant segregating with the condition was detected in CDH11 (c.1116_1117delinsGATCATCAG, p.(Ile372MetfsTer9)), which was then validated by using Sanger sequencing. CDH11 encodes cadherin 11 (osteo-cadherin) that regulates cell-cell adhesion, cell polarization and migration, as well as osteogenic differentiation. Further experiments revealed that CDH11 expression was decreased in patient-derived fibroblasts as compared to the heterozygous parent and another healthy donor. Immunostaining showed absence of the protein expression in patient fibroblasts. In addition, cell proliferation rate was slow and osteogenic differentiation potential was delayed. We consider that this study reveals loss-of-function mutations in CDH11 as a probable cause of this phenotype. Next generation sequencing in further patients would both prove this gene as causative, and finely delineate this clinical spectrum further contributing in identification of other possibly involved gene(s). © 2017 Wiley Periodicals, Inc.

  14. Characterization of V71M mutation in the aquaporin-2 gene causing ...

    Indian Academy of Sciences (India)

    In this study, we report a consanguineous family with an autosomal recessive NDI. We have identified a c.211G>A mutation in AQP2 gene. It is the first mutation in this gene reported in North Africa. Structural modelling of the V71M mutant has shown that the cavity corresponding to the water channel seems to be reduced.

  15. A novel mutation in the ELOVL4 gene causes autosomal dominant Stargardt-like macular dystrophy.

    NARCIS (Netherlands)

    Maugeri, A.; Meire, F.; Hoyng, C.B.; Vink, C.W.; Regemorter, N. van; Karan, G.; Yang, Z.; Cremers, F.P.M.; Zhang, K.

    2004-01-01

    PURPOSE: To conduct clinical and genetic studies in a European family with autosomal dominant Stargardt-like macular dystrophy (adSTGD-like MD) and to investigate the functional consequences of a novel ELOVL4 mutation. METHODS: Ophthalmic examination and mutation screening by direct sequencing of

  16. Mutations in the Gene PRRT2 Cause Paroxysmal Kinesigenic Dyskinesia with Infantile Convulsions

    NARCIS (Netherlands)

    Lee, Hsien-Yang; Huang, Yong; Bruneau, Nadine; Roll, Patrice; Roberson, Elisha D. O.; Hermann, Mark; Quinn, Emily; Maas, James; Edwards, Robert; Ashizawa, Tetsuo; Baykan, Betul; Bhatia, Kailash; Bressman, Susan; Bruno, Michiko K.; Brunt, Ewout R.; Caraballo, Roberto; Echenne, Bernard; Fejerman, Natalio; Frucht, Steve; Gurnett, Christina A.; Hirsch, Edouard; Houlden, Henry; Jankovic, Joseph; Lee, Wei-Ling; Lynch, David R.; Mohammed, Shehla; Mueller, Ulrich; Nespeca, Mark P.; Renner, David; Rochette, Jacques; Rudolf, Gabrielle; Saiki, Shinji; Soong, Bing-Wen; Swoboda, Kathryn J.; Tucker, Sam; Wood, Nicholas; Hanna, Michael; Bowcock, Anne M.; Szepetowski, Pierre; Fu, Ying-Hui; Ptacek, Louis J.

    2012-01-01

    Paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC) is an episodic movement disorder with autosomal-dominant inheritance and high penetrance, but the causative genetic mutation is unknown. We have now identified four truncating mutations involving the gene PRRT2 in the vast

  17. De novo mutations of KIAA2022 in females cause intellectual disability and intractable epilepsy

    NARCIS (Netherlands)

    de Lange, Iris M; Helbig, Katherine L; Weckhuysen, Sarah; Møller, Rikke S; Velinov, Milen; Dolzhanskaya, Natalia; Marsh, Eric; Helbig, Ingo; Devinsky, Orrin; Tang, Sha; Mefford, Heather C; Myers, Candace T; van Paesschen, Wim; Striano, Pasquale; van Gassen, Koen; van Kempen, Marjan; de Kovel, Carolien G F; Piard, Juliette; Minassian, Berge A; Nezarati, Marjan M; Pessoa, André; Jacquette, Aurelia; Maher, Bridget; Balestrini, Simona; Sisodiya, Sanjay; Warde, Marie Therese Abi; De St Martin, Anne; Chelly, Jamel; van 't Slot, Ruben; Van Maldergem, Lionel; Brilstra, Eva H; Koeleman, Bobby P C

    2016-01-01

    BACKGROUND: Mutations in the KIAA2022 gene have been reported in male patients with X-linked intellectual disability, and related female carriers were unaffected. Here, we report 14 female patients who carry a heterozygous de novo KIAA2022 mutation and share a phenotype characterised by intellectual

  18. De novo mutations of KIAA2022 in females cause intellectual disability and intractable epilepsy

    DEFF Research Database (Denmark)

    de Lange, Iris M; Helbig, Katherine L; Weckhuysen, Sarah

    2016-01-01

    BACKGROUND: Mutations in the KIAA2022 gene have been reported in male patients with X-linked intellectual disability, and related female carriers were unaffected. Here, we report 14 female patients who carry a heterozygous de novo KIAA2022 mutation and share a phenotype characterised by intellect...

  19. De novo mutations in the genome organizer CTCF cause intellectual disability

    DEFF Research Database (Denmark)

    Gregor, Anne; Oti, Martin; Kouwenhoven, Evelyn N

    2013-01-01

    mutations and one de novo missense mutation in CTCF in individuals with intellectual disability, microcephaly, and growth retardation. Furthermore, an individual with a larger deletion including CTCF was identified. CTCF (CCCTC-binding factor) is one of the most important chromatin organizers in vertebrates...

  20. Origin and migration of an Afrikaner founder mutation FHAfrikaner-2 (V408M) causing familial hypercholesterolemia

    NARCIS (Netherlands)

    Defesche, J. C.; van Diermen, D. E.; Hayden, M. R.; Kastelein, J. P.

    1996-01-01

    Of the three major Afrikaner founder mutations, responsible for more than 95% of Familial Hypercholesterolemia cases among South African Afrikaners, one mutation called V408M or FHAfrikaner-2 was identified in the Netherlands. Subsequent analysis of a group of Canadian patients of Dutch origin with

  1. De novo mutations in synaptic transmission genes including DNM1 cause epileptic encephalopathies

    DEFF Research Database (Denmark)

    2014-01-01

    analyzed exome-sequencing data of 356 trios with the "classical" epileptic encephalopathies, infantile spasms and Lennox Gastaut syndrome, including 264 trios previously analyzed by the Epi4K/EPGP consortium. In this expanded cohort, we find 429 de novo mutations, including de novo mutations in DNM1...

  2. Two novel compound heterozygous mutations in the BCKDHB gene that cause the intermittent form of maple syrup urine disease.

    Science.gov (United States)

    Guo, Yi; Liming, Liu; Jiang, Li

    2015-12-01

    Intermittent maple syrup urine disease (MSUD) is a potentially life-threatening metabolic disorder caused by a deficiency of branched chain α-ketoacid dehydrogenase (BCKD) complex. In contrast to classic MSUD, children with the intermittent form usually have an atypical clinical manifestation. Here, we describe the presenting symptoms and clinical course of a Chinese boy with intermittent MSUD. Mutation analysis identified two previously unreported mutations in exon 7 of the BCKDHB gene: c.767A > G (p.Y256C) and c.768C > G (p.Y256X); the parents were each heterozygous for one of these mutations. In silico analysis predicted Y256C probably affects protein structure; Y256X leads to a premature stop codon. This case demonstrates intermittent MSUD should be suspected in cases with symptoms of recurrent encephalopathy, especially ataxia or marked drowsiness, which usually present after the neonatal period and in conjunction with infection. symmetrical basal ganglia damage but normal myelination in the posterior limb will assist differential diagnosis; alloisoleucine is a useful diagnostic marker and mutation analysis may be of prognostic value. These novel mutations Y256C and Y256X result in the clinical manifestation of a variant form of MSUD, expanding the mutation spectrum of this disease.

  3. Multiple nevoid basal cell carcinoma syndrome associated with congenital orbital teratoma, caused by a PTCH1 frameshift mutation.

    Science.gov (United States)

    Rodrigues, A L; Carvalho, A; Cabral, R; Carneiro, V; Gilardi, P; Duarte, C P; Puente-Prieto, J; Santos, P; Mota-Vieira, L

    2014-07-25

    Gorlin-Goltz syndrome, or nevoid basal cell carcinoma syndrome (NBCCS), is a rare autosomal dominant disorder caused by mutations in the PTCH1 gene and shows a high level of penetrance and variable expressivity. The syndrome is characterized by developmental abnormalities or neoplasms and is diagnosed with 2 major criteria, or with 1 major and 2 minor criteria. Here, we report a new clinical manifestation associated with this syndrome in a boy affected by NBCCS who had congenital orbital teratoma at birth. Later, at the age of 15 years, he presented with 4 major and 4 minor criteria of NBCCS, including multiple basal cell carcinoma and 2 odontogenic keratocysts of the jaw, both confirmed by histology, more than 5 palmar pits, calcification of the cerebral falx, extensive meningeal calcifications, macrocephaly, hypertelorism, frontal bosses, and kyphoscoliosis. PTCH1 mutation analysis revealed the heterozygous germline mutation c.290dupA. This mutation generated a frameshift within exon 2 and an early premature stop codon (p.Asn97LysfsX43), predicting a truncated protein with complete loss of function. Identification of this mutation is useful for genetic counseling. Although the clinical symptoms are well-known, our case contributes to the understanding of phenotypic variability in NBCCS, highlighting that PTCH1 mutations cannot be used for predicting disease burden and reinforces the need of a multidisciplinary team in the diagnosis, treatment, and follow-up of NBCCS patients.

  4. NK cells are intrinsically functional in pigs with Severe Combined Immunodeficiency (SCID) caused by spontaneous mutations in the Artemis gene

    Science.gov (United States)

    We have identified Severe Combined Immunodeficiency (SCID) in a line of Yorkshire pigs at Iowa State University. These SCID pigs lack B-cells and T-cells, but possess Natural Killer (NK) cells. This SCID phenotype is caused by recessive mutations in the Artemis gene. Interestingly, two human tumor c...

  5. Early microgliosis precedes neuronal loss and behavioural impairment in mice with a frontotemporal dementia-causing CHMP2B mutation

    DEFF Research Database (Denmark)

    Clayton, Emma L.; Mancuso, Renzo; Nielsen, Troels Tolstrup

    2017-01-01

    Frontotemporal dementia (FTD)-causing mutations in the CHMP2B gene lead to the generation of mutant C-terminally truncated CHMP2B. We report that transgenic mice expressing endogenous levels of mutant CHMP2B developed late-onset brain volume loss associated with frank neuronal loss and FTD-like c...

  6. Phenotypic spectrum of autosomal recessive cone-rod dystrophies caused by mutations in the ABCA4 (ABCR) gene.

    NARCIS (Netherlands)

    Klevering, B.J.; Blankenagel, A.; Maugeri, A.; Cremers, F.P.M.; Hoyng, C.B.; Rohrschneider, K.

    2002-01-01

    PURPOSE: To describe the phenotype of 12 patients with autosomal recessive or isolated cone-rod types of progressive retinal degeneration (CRD) caused by mutations in the ABCA4 gene. METHODS: The charts of patients who had originally received a diagnosis of isolated or autosomal recessive CRD were

  7. Atypical early-onset Alzheimer's disease caused by the Iranian APP mutation

    DEFF Research Database (Denmark)

    Lindquist, S.G.; Nielsen, J.E.; Stokholm, J.

    2008-01-01

    BACKGROUND: Approximately 1% of all cases of Alzheimer's disease are inherited autosomal dominantly, and to date, three causative genes have been found, the Presenilin 1 (PSEN1) gene, the Presenilin 2 (PSEN2) gene and the Amyloid precursor protein (APP) gene. We describe atypical phenotypic...... features in a family with a pathogenic APP gene mutation and discuss possible explanations for these atypical features. METHODS AND RESULTS: We report a family with a history of dementia compatible with autosomal dominant transmission. The disease course in the proband was not typical for Alzheimer...... mutation, APP Thr714Ala (the Iranian mutation). CONCLUSIONS: The atypical clinical phenotype with long prodromal phase, autonomic failure and seizures in this new proband with the APP Thr714Ala mutation illustrates the clinical heterogeneity in families with identical pathogenic mutations Udgivelsesdato...

  8. A novel mutation of α-galactosidase A gene causes Fabry disease mimicking primary erythromelalgia in a Chinese family.

    Science.gov (United States)

    Ge, Wei; Wei, Bin; Zhu, Hao; Miao, Zhigang; Zhang, Weimin; Leng, Cuihua; Li, Jizhen; Zhang, Dan; Sun, Miao; Xu, Xingshun

    2017-05-01

    Fabry disease is an X-linked genetic disorder caused by the mutations of α-galactosidase A (GLA, MIM 300644) gene presenting with various clinical symptoms including small-fiber peripheral neuropathy and limb burning pain. Here, we reported a Chinese pedigree with the initial diagnosis of primary erythromelalgia in an autosomal dominant (AD)-inherited pattern. Mutation analysis of SCN9A and GLA genes by direct sequencing and functional analysis of a novel mutation of GLA in cells were performed. Our data did not show any pathological mutations in SCN9A gene; however, a novel missense mutation c.139T>C (p.W47R) of GLA was identified in a male proband as well as two female carriers in this family. Enzyme assay of α-galactosidase A activity showed deficient enzyme activity in male patients and female carriers, further confirming the diagnosis of Fabry disease. Finally, a functional analysis indicated that the replacement of the 47th amino acid tryptophan (W47) with arginine (W47R) or glycine (W47G) led to reduced activity of α-galactosidase A in 293T cells. Therefore, these findings demonstrated that the novel mutation p.W47R of GLA is the cause of Fabry disease. Because Fabry disease and primary erythromelalgia share similar symptoms, it is a good strategy for clinical physicians to perform genetic mutation screenings on both SCN9A and GLA genes in those patients with limb burning pain but without a clear inheritant pattern.

  9. A novel missense mutation in the SLC26A4 gene causes nonsyndromic hearing loss and enlarged vestibular aqueduct.

    Science.gov (United States)

    He, Xiaoguang; Peng, Qi; Li, Siping; Zhu, Pengyuan; Wu, Chunqiu; Rao, Chunbao; Chang, Jiang; Xie, Mingyu; Zhong, Baimao; Lu, Xiaomei

    2017-04-01

    We aimed to investigate the genetic causes of hearing loss in a Chinese proband with nonsyndromic hearing loss and enlarged vestibular aqueduct syndrome. We conducted clinical and genetic evaluations in a deaf proband and his normal-hearing parents. Multiplex PCR technology combined with Ion Torrent™ next-generation sequencing technology was used to detect the pathogenic mutations. As a control, a group of 1500 previously studied healthy newborns from the same ethnic background were subjected to deafness gene screening using the same method as in our previous study. The proband harbored two mutations in the SLC26A4 gene in the form of compound heterozygosity. He was found to be heterozygous for a novel mutation named c.1742 G > T (p.Arg581Met) in exon 13 and for the known mutation c.589 G > A (p.Gly197Arg). These variants were carried in the heterozygous state by the parents and therefore co-segregated with the genetic disease. The c.1742 G > T (p.Arg581Met) mutation was absent in 1500 healthy newborns. Protein alignment indicated high evolutionary conservation of the p.R581 residue, and this mutation was predicted by PolyPhen-2 and other online tools to be damaging. This study demonstrates that the novel mutation c.1742 G > T (p.Arg581Met) in compound heterozygosity with c.589 G > A in the SLC26A4 gene is the main cause of deafness in a family clinically diagnosed with enlarged vestibular aqueduct (EVA). Our study will provide a basic foundation for further investigations to elucidate the SLC26A4-related mechanisms of hearing loss. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. IVS8+1 DelG, a Novel Splice Site Mutation Causing DFNA5 Deafness in a Chinese Family.

    Science.gov (United States)

    Li-Yang, Mei-Na; Shen, Xiao-Fei; Wei, Qin-Jun; Yao, Jun; Lu, Ya-Jie; Cao, Xin; Xing, Guang-Qian

    2015-09-20

    Nonsyndromic hearing loss (NSHL) is highly heterogeneous, in which more than 90 causative genes have currently been identified. DFNA5 is one of the deafness genes that known to cause autosomal dominant NSHL. Until date, only five DFNA5 mutations have been described in eight families worldwide. In this study, we reported the identification of a novel pathogenic mutation causing DFNA5 deafness in a five-generation Chinese family. After detailed clinical evaluations of this family, the genomic DNA of three affected individuals was selected for targeted exome sequencing of 101 known deafness genes, as well as mitochondrial DNA and microRNA regions. Co-segregation analysis between the hearing loss and the candidate variant was confirmed in available family members by direct polymerase chain reaction (PCR)-Sanger sequencing. Real-time PCR (RT-PCR) was performed to investigate the potential effect of the pathogenic mutation on messenger RNA splicing. Clinical evaluations revealed a similar deafness phenotype in this family to that of previously reported DFNA5 families with autosomal dominant, late-onset hearing loss. Molecular analysis identified a novel splice site mutation in DFNA5 intron 8 (IVS8+1 delG). The mutation segregated with the hearing loss of the family and was absent in 120 unrelated control DNA samples of Chinese origin. RT-PCR showed skipping of exon 8 in the mutant transcript. We identified a novel DFNA5 mutation IVS8+1 delG in a Chinese family which led to skipping of exon 8. This is the sixth DFNA5 mutation relates to hearing loss and the second one in DFNA5 intron 8. Our findings provide further support to the hypothesis that the DFNA5-associated hearing loss represents a mechanism of gain-of-function.

  11. GRIN2D Recurrent De Novo Dominant Mutation Causes a Severe Epileptic Encephalopathy Treatable with NMDA Receptor Channel Blockers.

    Science.gov (United States)

    Li, Dong; Yuan, Hongjie; Ortiz-Gonzalez, Xilma R; Marsh, Eric D; Tian, Lifeng; McCormick, Elizabeth M; Kosobucki, Gabrielle J; Chen, Wenjuan; Schulien, Anthony J; Chiavacci, Rosetta; Tankovic, Anel; Naase, Claudia; Brueckner, Frieder; von Stülpnagel-Steinbeis, Celina; Hu, Chun; Kusumoto, Hirofumi; Hedrich, Ulrike B S; Elsen, Gina; Hörtnagel, Konstanze; Aizenman, Elias; Lemke, Johannes R; Hakonarson, Hakon; Traynelis, Stephen F; Falk, Marni J

    2016-10-06

    N-methyl-D-aspartate receptors (NMDARs) are ligand-gated cation channels that mediate excitatory synaptic transmission. Genetic mutations in multiple NMDAR subunits cause various childhood epilepsy syndromes. Here, we report a de novo recurrent heterozygous missense mutation-c.1999G>A (p.Val667Ile)-in a NMDAR gene previously unrecognized to harbor disease-causing mutations, GRIN2D, identified by exome and candidate panel sequencing in two unrelated children with epileptic encephalopathy. The resulting GluN2D p.Val667Ile exchange occurs in the M3 transmembrane domain involved in channel gating. This gain-of-function mutation increases glutamate and glycine potency by 2-fold, increases channel open probability by 6-fold, and reduces receptor sensitivity to endogenous negative modulators such as extracellular protons. Moreover, this mutation prolongs the deactivation time course after glutamate removal, which controls the synaptic time course. Transfection of cultured neurons with human GRIN2D cDNA harboring c.1999G>A leads to dendritic swelling and neuronal cell death, suggestive of excitotoxicity mediated by NMDAR over-activation. Because both individuals' seizures had proven refractory to conventional antiepileptic medications, the sensitivity of mutant NMDARs to FDA-approved NMDAR antagonists was evaluated. Based on these results, oral memantine was administered to both children, with resulting mild to moderate improvement in seizure burden and development. The older proband subsequently developed refractory status epilepticus, with dramatic electroclinical improvement upon treatment with ketamine and magnesium. Overall, these results suggest that NMDAR antagonists can be useful as adjuvant epilepsy therapy in individuals with GRIN2D gain-of-function mutations. This work further demonstrates the value of functionally evaluating a mutation, enabling mechanistic understanding and therapeutic modeling to realize precision medicine for epilepsy. Copyright © 2016

  12. Novel biallelic mutations in the PNPT1 gene encoding a mitochondrial-RNA-import protein PNPase cause delayed myelination.

    Science.gov (United States)

    Sato, R; Arai-Ichinoi, N; Kikuchi, A; Matsuhashi, T; Numata-Uematsu, Y; Uematsu, M; Fujii, Y; Murayama, K; Ohtake, A; Abe, T; Kure, S

    2018-02-01

    Recent studies suggest that impaired transcription or mitochondrial translation of small RNAs can cause abnormal myelination. A polynucleotide phosphorylase (PNPase) encoded by PNPT1 facilitates the import of small RNAs into mitochondria. PNPT1 mutations have been reported in patients with neurodevelopmental diseases with mitochondrial dysfunction. We report here 2 siblings with PNPT1 mutations who presented delayed myelination as well as mitochondrial dysfunction. We identified compound heterozygous mutations (c.227G>A; p.Gly76Asp and c.574C>T; p.Arg192*) in PNPT1 by quartet whole-exome sequencing. Analyses of skin fibroblasts from the patient showed that PNPase expression was markedly decreased and that import of the small RNA RNaseP into mitochondria was impaired. Exogenous expression of wild-type PNPT1, but not mutants, rescued ATP production in patient skin fibroblasts, suggesting the pathogenicity of the identified mutations. Our cases expand the phenotypic spectrum of PNPT1 mutations that can cause delayed myelination. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Sar1-GTPase-dependent ER exit of KATP channels revealed by a mutation causing congenital hyperinsulinism

    DEFF Research Database (Denmark)

    Taneja, Tarvinder K; Mankouri, Jamel; Karnik, Rucha

    2009-01-01

    The ATP-sensitive potassium (K(ATP)) channel controls insulin secretion by coupling glucose metabolism to excitability of the pancreatic beta-cell membrane. The channel comprises four subunits each of Kir6.2 and the sulphonylurea receptor (SUR1), encoded by KCNJ11 and ABCC8, respectively. Mutations...... caused by one such mutation in Kir6.2, E282K. The study led to the discovery that Kir6.2 contains a di-acidic ER exit signal, (280)DLE(282), which promotes concentration of the channel into COPII-enriched ER exit sites prior to ER export via a process that requires Sar1-GTPase. The E282K mutation...... abrogates the exit signal, and thereby prevents the ER export and surface expression of the channel. When co-expressed, the mutant subunit was able to associate with the wild-type Kir6.2 and form functional channels. Thus unlike most mutations, the E282K mutation does not cause protein mis-folding. Since...

  14. Altered heme catabolism by heme oxygenase-1 caused by mutations in human NADPH cytochrome P450 reductase

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Amit V., E-mail: amit@pandeylab.org [Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern (Switzerland); Flueck, Christa E.; Mullis, Primus E. [Pediatric Endocrinology, Diabetology and Metabolism, Department of Clinical Research, University of Bern, Tiefenaustrasse 120c, CH-3004 Bern (Switzerland)

    2010-09-24

    Research highlights: {yields} Mutations in POR identified from patients lead to reduced HO-1 activities. {yields} POR mutation Y181D affecting FMN binding results in total loss of HO-1 activity. {yields} POR mutations A287P, C569Y and V608F, lost 50-70% activity. {yields} Mutations in FAD binding domain, R457H, Y459H and V492E lost all HO-1 activity. {yields} POR polymorphisms P228L, R316W, G413S, A503V and G504R have normal activity. -- Abstract: Human heme oxygenase-1 (HO-1) carries out heme catabolism supported by electrons supplied from the NADPH through NADPH P450 reductase (POR, CPR). Previously we have shown that mutations in human POR cause a rare form of congenital adrenal hyperplasia. In this study, we have evaluated the effects of mutations in POR on HO-1 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified HO-1 to measure heme degradation in a coupled assay using biliverdin reductase. Here we show that mutations in POR found in patients may reduce HO-1 activity, potentially influencing heme catabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had total loss of HO-1 activity, while POR mutations A287P, C569Y and V608F lost 50-70% activity. The POR variants P228L, R316W and G413S, A503V and G504R identified as polymorphs had close to WT activity. Loss of HO-1 activity may result in increased oxidative neurotoxicity, anemia, growth retardation and iron deposition. Further examination of patients affected with POR deficiency will be required to assess the metabolic effects of reduced HO-1 activity in affected individuals.

  15. A synthetic combination of mutations, including fs(1)pyrSu(b), rSu(b) and b, causes female sterility and reduces embryonic viability in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Piskur, Jure; Gojkovic, Zoran; Bahn, E.

    1999-01-01

    A Drosophila melangaster mutant, fs(1)pyr(Su(b)), carrying a mutation that maps to the tip of the X chromosome, has been isolated. The mutation, when present alone, does not confer a detectable phenotype. However, this mutation causes female sterility and reduces embryonic viability when combined...

  16. ALS5/SPG11/KIAA1840 mutations cause autosomal recessive axonal Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Montecchiani, Celeste; Pedace, Lucia; Lo Giudice, Temistocle; Casella, Antonella; Mearini, Marzia; Gaudiello, Fabrizio; Pedroso, José L; Terracciano, Chiara; Caltagirone, Carlo; Massa, Roberto; St George-Hyslop, Peter H; Barsottini, Orlando G P; Kawarai, Toshitaka; Orlacchio, Antonio

    2016-01-01

    Charcot-Marie-Tooth disease is a group of hereditary peripheral neuropathies that share clinical characteristics of progressive distal muscle weakness and atrophy, foot deformities, distal sensory loss, as well as diminished tendon reflexes. Hundreds of causative DNA changes have been found, but much of the genetic basis of the disease is still unexplained. Mutations in the ALS5/SPG11/KIAA1840 gene are a frequent cause of autosomal recessive hereditary spastic paraplegia with thin corpus callosum and peripheral axonal neuropathy, and account for ∼ 40% of autosomal recessive juvenile amyotrophic lateral sclerosis. The overlap of axonal Charcot-Marie-Tooth disease with both diseases, as well as the common autosomal recessive inheritance pattern of thin corpus callosum and axonal Charcot-Marie-Tooth disease in three related patients, prompted us to analyse the ALS5/SPG11/KIAA1840 gene in affected individuals with autosomal recessive axonal Charcot-Marie-Tooth disease. We investigated 28 unrelated families with autosomal recessive axonal Charcot-Marie-Tooth disease defined by clinical, electrophysiological, as well as pathological evaluation. Besides, we screened for all the known genes related to axonal autosomal recessive Charcot-Marie-Tooth disease (CMT2A2/HMSN2A2/MFN2, CMT2B1/LMNA, CMT2B2/MED25, CMT2B5/NEFL, ARCMT2F/dHMN2B/HSPB1, CMT2K/GDAP1, CMT2P/LRSAM1, CMT2R/TRIM2, CMT2S/IGHMBP2, CMT2T/HSJ1, CMTRID/COX6A1, ARAN-NM/HINT and GAN/GAN), for the genes related to autosomal recessive hereditary spastic paraplegia with thin corpus callosum and axonal peripheral neuropathy (SPG7/PGN, SPG15/ZFYVE26, SPG21/ACP33, SPG35/FA2H, SPG46/GBA2, SPG55/C12orf65 and SPG56/CYP2U1), as well as for the causative gene of peripheral neuropathy with or without agenesis of the corpus callosum (SLC12A6). Mitochondrial disorders related to Charcot-Marie-Tooth disease type 2 were also excluded by sequencing POLG and TYMP genes. An additional locus for autosomal recessive Charcot

  17. ALS5/SPG11/ KIAA1840 mutations cause autosomal recessive axonal Charcot–Marie–Tooth disease

    Science.gov (United States)

    Montecchiani, Celeste; Pedace, Lucia; Lo Giudice, Temistocle; Casella, Antonella; Mearini, Marzia; Gaudiello, Fabrizio; Pedroso, José L.; Terracciano, Chiara; Caltagirone, Carlo; Massa, Roberto; St George-Hyslop, Peter H.; Barsottini, Orlando G. P.; Kawarai, Toshitaka

    2016-01-01

    Abstract Charcot–Marie–Tooth disease is a group of hereditary peripheral neuropathies that share clinical characteristics of progressive distal muscle weakness and atrophy, foot deformities, distal sensory loss, as well as diminished tendon reflexes. Hundreds of causative DNA changes have been found, but much of the genetic basis of the disease is still unexplained. Mutations in the ALS5/SPG11/ KIAA1840 gene are a frequent cause of autosomal recessive hereditary spastic paraplegia with thin corpus callosum and peripheral axonal neuropathy, and account for ∼40% of autosomal recessive juvenile amyotrophic lateral sclerosis. The overlap of axonal Charcot–Marie–Tooth disease with both diseases, as well as the common autosomal recessive inheritance pattern of thin corpus callosum and axonal Charcot–Marie–Tooth disease in three related patients, prompted us to analyse the ALS5/SPG11/ KIAA1840 gene in affected individuals with autosomal recessive axonal Charcot–Marie–Tooth disease. We investigated 28 unrelated families with autosomal recessive axonal Charcot–Marie–Tooth disease defined by clinical, electrophysiological, as well as pathological evaluation. Besides, we screened for all the known genes related to axonal autosomal recessive Charcot–Marie-Tooth disease (CMT2A2/HMSN2A2/ MFN2 , CMT2B1/ LMNA , CMT2B2/ MED25 , CMT2B5/ NEFL , ARCMT2F/dHMN2B/ HSPB1 , CMT2K/ GDAP1 , CMT2P/ LRSAM1 , CMT2R/ TRIM2 , CMT2S/ IGHMBP2 , CMT2T/ HSJ1 , CMTRID/ COX6A1 , ARAN-NM/ HINT and GAN/ GAN ), for the genes related to autosomal recessive hereditary spastic paraplegia with thin corpus callosum and axonal peripheral neuropathy (SPG7/ PGN , SPG15/ ZFYVE26, SPG21/ ACP33 , SPG35/ FA2H , SPG46/ GBA2 , SPG55/ C12orf65 and SPG56/ CYP2U1 ), as well as for the causative gene of peripheral neuropathy with or without agenesis of the corpus callosum ( SLC12A6 ) . Mitochondrial disorders related to Charcot–Marie–Tooth disease type 2 were also excluded by sequencing POLG and

  18. Characterization of novel StAR (steroidogenic acute regulatory protein mutations causing non-classic lipoid adrenal hyperplasia.

    Directory of Open Access Journals (Sweden)

    Christa E Flück

    Full Text Available CONTEXT: Steroidogenic acute regulatory protein (StAR is crucial for transport of cholesterol to mitochondria where biosynthesis of steroids is initiated. Loss of StAR function causes lipoid congenital adrenal hyperplasia (LCAH. OBJECTIVE: StAR gene mutations causing partial loss of function manifest atypical and may be mistaken as familial glucocorticoid deficiency. Only a few mutations have been reported. DESIGN: To report clinical, biochemical, genetic, protein structure and functional data on two novel StAR mutations, and to compare them with published literature. SETTING: Collaboration between the University Children's Hospital Bern, Switzerland, and the CIBERER, Hospital Vall d'Hebron, Autonomous University, Barcelona, Spain. PATIENTS: Two subjects of a non-consanguineous Caucasian family were studied. The 46,XX phenotypic normal female was diagnosed with adrenal insufficiency at the age of 10 months, had normal pubertal development and still has no signs of hypergonodatropic hypogonadism at 32 years of age. Her 46,XY brother was born with normal male external genitalia and was diagnosed with adrenal insufficiency at 14 months. Puberty was normal and no signs of hypergonadotropic hypogonadism are present at 29 years of age. RESULTS: StAR gene analysis revealed two novel compound heterozygote mutations T44HfsX3 and G221S. T44HfsX3 is a loss-of-function StAR mutation. G221S retains partial activity (∼30% and is therefore responsible for a milder, non-classic phenotype. G221S is located in the cholesterol binding pocket and seems to alter binding/release of cholesterol. CONCLUSIONS: StAR mutations located in the cholesterol binding pocket (V187M, R188C, R192C, G221D/S seem to cause non-classic lipoid CAH. Accuracy of genotype-phenotype prediction by in vitro testing may vary with the assays employed.

  19. Mutations in the sodium channel gene SCN2A cause neonatal epilepsy with late-onset episodic ataxia.

    Science.gov (United States)

    Schwarz, N; Hahn, A; Bast, T; Müller, S; Löffler, H; Maljevic, S; Gaily, E; Prehl, I; Biskup, S; Joensuu, T; Lehesjoki, A-E; Neubauer, B A; Lerche, H; Hedrich, U B S

    2016-02-01

    Mutations in SCN2A cause epilepsy syndromes of variable severity including neonatal-infantile seizures. In one case, we previously described additional childhood-onset episodic ataxia. Here, we corroborate and detail the latter phenotype in three further cases. We describe the clinical characteristics, identify the causative SCN2A mutations and determine their functional consequences using whole-cell patch-clamping in mammalian cells. In total, four probands presented with neonatal-onset seizures remitting after five to 13 months. In early childhood, they started to experience repeated episodes of ataxia, accompanied in part by headache or back pain lasting minutes to several hours. In two of the new cases, we detected the novel mutation p.Arg1882Gly. While this mutation occurred de novo in both patients, one of them carries an additional known variant on the same SCN2A allele, inherited from the unaffected father (p.Gly1522Ala). Whereas p.Arg1882Gly alone shifted the activation curve by -4 mV, the combination of both variants did not affect activation, but caused a depolarizing shift of voltage-dependent inactivation, and a significant increase in Na(+) current density and protein production. p.Gly1522Ala alone did not change channel gating. The third new proband carries the same de novo SCN2A gain-of-function mutation as our first published case (p.Ala263Val). Our findings broaden the clinical spectrum observed with SCN2A gain-of-function mutations, showing that fairly different biophysical mechanisms can cause a convergent clinical phenotype of neonatal seizures and later onset episodic ataxia.

  20. Identification of an Agrin Mutation that Causes Congenital Myasthenia and Affects Synapse Function

    Science.gov (United States)

    Huzé, Caroline; Bauché, Stéphanie; Richard, Pascale; Chevessier, Frédéric; Goillot, Evelyne; Gaudon, Karen; Ben Ammar, Asma; Chaboud, Annie; Grosjean, Isabelle; Lecuyer, Heba-Aude; Bernard, Véronique; Rouche, Andrée; Alexandri, Nektaria; Kuntzer, Thierry; Fardeau, Michel; Fournier, Emmanuel; Brancaccio, Andrea; Rüegg, Markus A.; Koenig, Jeanine; Eymard, Bruno; Schaeffer, Laurent; Hantaï, Daniel

    2009-01-01

    We report the case of a congenital myasthenic syndrome due to a mutation in AGRN, the gene encoding agrin, an extracellular matrix molecule released by the nerve and critical for formation of the neuromuscular junction. Gene analysis identified a homozygous missense mutation, c.5125G>C, leading to the p.Gly1709Arg variant. The muscle-biopsy specimen showed a major disorganization of the neuromuscular junction, including changes in the nerve-terminal cytoskeleton and fragmentation of the synaptic gutters. Experiments performed in nonmuscle cells or in cultured C2C12 myotubes and using recombinant mini-agrin for the mutated and the wild-type forms showed that the mutated form did not impair the activation of MuSK or change the total number of induced acetylcholine receptor aggregates. A solid-phase assay using the dystrophin glycoprotein complex showed that the mutation did not affect the binding of agrin to α-dystroglycan. Injection of wild-type or mutated agrin into rat soleus muscle induced the formation of nonsynaptic acetylcholine receptor clusters, but the mutant protein specifically destabilized the endogenous neuromuscular junctions. Importantly, the changes observed in rat muscle injected with mutant agrin recapitulated the pre- and post-synaptic modifications observed in the patient. These results indicate that the mutation does not interfere with the ability of agrin to induce postsynaptic structures but that it dramatically perturbs the maintenance of the neuromuscular junction. PMID:19631309

  1. Biallelic Mutations in PATL2 Cause Female Infertility Characterized by Oocyte Maturation Arrest.

    Science.gov (United States)

    Chen, Biaobang; Zhang, Zhihua; Sun, Xiaoxi; Kuang, Yanping; Mao, Xiaoyan; Wang, Xueqian; Yan, Zheng; Li, Bin; Xu, Yao; Yu, Min; Fu, Jing; Mu, Jian; Zhou, Zhou; Li, Qiaoli; Jin, Li; He, Lin; Sang, Qing; Wang, Lei

    2017-10-05

    Oocyte maturation arrest results in female infertility, but the genetic determinants of human oocyte maturation arrest remain largely unknown. Previously, we identified TUBB8 mutations responsible for human oocyte maturation arrest, indicating the important role of genetic factors in the disorder. However, TUBB8 mutations account for only around 30% of individuals with oocyte maturation arrest; thus, the disorder is likely to involve other genetic factors that are as yet unknown. Here, we initially identified a homozygous nonsense mutation of PATL2 (c.784C>T [p.Arg262 ∗ ]) in a consanguineous family with a phenotype characterized by human oocyte germinal vesicle (GV) arrest. Subsequent mutation screening of PATL2 in a cohort of 179 individuals identified four additional independent individuals with compound-heterozygous PATL2 mutations with slight phenotypic variability. A genetic burden test further confirmed the genetic contribution of PATL2 to human oocyte maturation arrest. By western blot in HeLa cells, identification of splicing events in affected individuals' granulosa cells, and immunostaining in affected individuals' oocytes, we provide evidence that mutations in PATL2 lead to decreased amounts of protein. These findings suggest an important role for PATL2 mutations in oocyte maturation arrest and expand our understanding of the genetic basis of female infertility. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  2. PYCR2 Mutations cause a lethal syndrome of microcephaly and failure to thrive.

    Science.gov (United States)

    Zaki, Maha S; Bhat, Gifty; Sultan, Tipu; Issa, Mahmoud; Jung, Hea-Jin; Dikoglu, Esra; Selim, Laila; G Mahmoud, Imam; Abdel-Hamid, Mohamed S; Abdel-Salam, Ghada; Marin-Valencia, Isaac; Gleeson, Joseph G

    2016-07-01

    A study was undertaken to characterize the clinical features of the newly described hypomyelinating leukodystrophy type 10 with microcephaly. This is an autosomal recessive disorder mapped to chromosome 1q42.12 due to mutations in the PYCR2 gene, encoding an enzyme involved in proline synthesis in mitochondria. From several international clinics, 11 consanguineous families were identified with PYCR2 mutations by whole exome or targeted sequencing, with detailed clinical and radiological phenotyping. Selective mutations from patients were tested for effect on protein function. The characteristic clinical presentation of patients with PYCR2 mutations included failure to thrive, microcephaly, craniofacial dysmorphism, progressive psychomotor disability, hyperkinetic movements, and axial hypotonia with variable appendicular spasticity. Patients did not survive beyond the first decade of life. Brain magnetic resonance imaging showed global brain atrophy and white matter T2 hyperintensities. Routine serum metabolic profiles were unremarkable. Both nonsense and missense mutations were identified, which impaired protein multimerization. PYCR2-related syndrome represents a clinically recognizable condition in which PYCR2 mutations lead to protein dysfunction, not detectable on routine biochemical assessments. Mutations predict a poor outcome, probably as a result of impaired mitochondrial function. Ann Neurol 2016;80:59-70. © 2016 American Neurological Association.

  3. Compensatory mutations cause excess of antagonistic epistasis in RNA secondary structure folding

    Directory of Open Access Journals (Sweden)

    Adami Christoph

    2003-02-01

    Full Text Available Background The rate at which fitness declines as an organism's genome accumulates random mutations is an important variable in several evolutionary theories. At an intuitive level, it might seem natural that random mutations should tend to interact synergistically, such that the rate of mean fitness decline accelerates as the number of random mutations is increased. However, in a number of recent studies, a prevalence of antagonistic epistasis (the tendency of multiple mutations to have a mitigating rather than reinforcing effect has been observed. Results We studied in silico the net amount and form of epistatic interactions in RNA secondary structure folding by measuring the fraction of neutral mutants as a function of mutational distance d. We found a clear prevalence of antagonistic epistasis in RNA secondary structure folding. By relating the fraction of neutral mutants at distance d to the average neutrality at distance d, we showed that this prevalence derives from the existence of many compensatory mutations at larger mutational distances. Conclusions Our findings imply that the average direction of epistasis in simple fitness landscapes is directly related to the density with which fitness peaks are distributed in these landscapes.

  4. Molecular analysis on germline mutation caused by low-dose irradiation

    International Nuclear Information System (INIS)

    Uchiyama, R.; Fujikawa, K.; Nishimura, M.; Adzuma, H.; Shimada, Y.; Yamauchi, M.

    2003-01-01

    Full text: Genetic heterogeneity and a low frequency of germline mutation at single-copy gene loci have limited the direct measurement of germline mutation in human populations. Two conflicting results have been reported for the effect of ionizing radiation on germline mutation in human populations. A study conducted on the first-generation progeny of the survivors of the atomic bombs at Hiroshima and Nagasaki found no significant increase in germline mutations. On the other hand, a significant increase in germline mutation was reported among the human population in the Belarus area after the Chernobyl accident in 1986. We investigated the germline mutation at the molecular level using experimental mouse strains with different genetic backgrounds to assess the risk of ionizing radiation on human populations. The C3H male parents were exposed to X ray (0, 0.3, 1, and 3Gy) and mated with unexposed C57BL females after two weeks interval, so as to detect the germline mutation occurred at the spermatid stage. Genomic DNA samples were prepared from the both parents and F1s, and the genomic DNA sequences were compared between parents and offspring at the specific genomic gene loci, such as adenine phosphoribosyl transferase (aprt) gene and cytidine triphosphate synthetase (ctps) gene, using the automated DNA sequencer. Also hypervariable Pc-1 (Ms6-hm) minisatellite repeat locus was analyzed by using Southern blot hybridization technique. Our preliminary results indicated that the changes of the restriction DNA fragment length in offspring did not reflect the occurrence of the mutation, such as point mutation, insertion, and deletion, in the genomic gene loci including the intervening sequence (intron)

  5. Tafazzin gene mutations are uncommon causes of dilated cardiomyopathy in adults

    Directory of Open Access Journals (Sweden)

    Matthew Taylor

    2011-07-01

    Full Text Available Barth syndrome is an X-linked genetic condition featuring neutropenia, skeletal myopathy, and dilated cardiomyopathy in boys due to tafazzin (TAZ mutations. Pure dilated cardiomyopathy without other features of Barth syndrome may also result from TAZ mutations and survival into adulthood has been described. Although TAZ testing is routinely included in dilated cardiomyopathy panels in adults, the prevalence of TAZ mutations in the adult population, including women who may be at risk to develop later onset disease due to TAZ mutations, has not been measured. We screened 292 families with dilated cardiomyopathy (209 male and 83 female probands for TAZ mutations using denaturing high-performance liquid chromatography and sequence analysis. Putative mutations were evaluated based on standard criteria including screening available relatives and healthy controls and for effects on splicing efficiency in the case of one intronic variant. Two variants suspicious for being pathogenic were found in two unrelated families (c.387T>C, Phe128Ser and c.507C>T, Leu169Leu. The Phe128Ser variant had been previously reported as a pathogenic mutation; however we determined that this variant is instead a rare polymorphism restricted to African Americans. The Leu169Leu variant was detected in a male patient and altered RNA processing in our minigene assay supporting a pathogenic role. No mutations in female subjects were detected. Tafazzin mutations were rare in our population of adults with dilated cardiomyopathy and none were found in females. Our findings indicate that genetic testing for tafazzin should not be routinely performed in dilated cardiomyopathy as suggested by current guidelines. Furthermore, the Phe128Ser variant is not pathogenic, but likely represents a benign polymorphism in persons of African American ancestry.

  6. A newly distal hereditary motor neuropathy caused by a rare AIFM1 mutation.

    Science.gov (United States)

    Sancho, Paula; Sánchez-Monteagudo, Ana; Collado, Antonio; Marco-Marín, Clara; Domínguez-González, Cristina; Camacho, Ana; Knecht, Erwin; Espinós, Carmen; Lupo, Vincenzo

    2017-12-01

    In two siblings, who suffer from an early childhood-onset axonal polyneuropathy with exclusive involvement of motor fibers, the c.629T>C (p.F210S) mutation was identified in the X-linked AIFM1 gene, which encodes for the apoptosis-inducing factor (AIF). The mutation was predicted as deleterious, according to in silico analysis. A decreased expression of the AIF protein, altered cellular morphology, and a fragmented mitochondrial network were observed in the proband's fibroblasts. This new form of motor neuropathy expands the phenotypic spectrum of AIFM1 mutations and therefore, the AIFM1 gene should be considered in the diagnosis of hereditary motor neuropathies.

  7. Evolutionary constraints and the neutral theory. [mutation-caused nucleotide substitutions in DNA

    Science.gov (United States)

    Jukes, T. H.; Kimura, M.

    1984-01-01

    The neutral theory of molecular evolution postulates that nucleotide substitutions inherently take place in DNA as a result of point mutations followed by random genetic drift. In the absence of selective constraints, the substitution rate reaches the maximum value set by the mutation rate. The rate in globin pseudogenes is about 5 x 10 to the -9th substitutions per site per year in mammals. Rates slower than this indicate the presence of constraints imposed by negative (natural) selection, which rejects and discards deleterious mutations.

  8. Reciprocal mouse and human limb phenotypes caused by gain- and loss-of-function mutations affecting Lmbr1.

    OpenAIRE

    Clark, R M; Marker, P C; Roessler, E; Dutra, A; Schimenti, J C; Muenke, M; Kingsley, D M

    2001-01-01

    The major locus for dominant preaxial polydactyly in humans has been mapped to 7q36. In mice the dominant Hemimelic extra toes (Hx) and Hammertoe (Hm) mutations map to a homologous chromosomal region and cause similar limb defects. The Lmbr1 gene is entirely within the small critical intervals recently defined for both the mouse and human mutations and is misexpressed at the exact time that the mouse Hx phenotype becomes apparent during limb development. This result suggests that Lmbr1 may un...

  9. Early onset of hypokalaemic periodic paralysis caused by a novel mutation of the CACNA1S gene.

    OpenAIRE

    Chabrier, S.; Monnier, Nicole; Lunardi, Joël

    2008-01-01

    International audience; We report a precocious and atypical form of hypokalaemic periodic paralysis, with clinical manifestations at birth and first episodes of paralysis occurring as early as 1 year of age, although onset of this disease usually occurs between 5-35 years. Extensive molecular analysis showed that the disease was caused by a novel de novo p.Arg897Ser mutation in the CACNA1S gene. The mutation mapped to a new region of the protein, the S4 voltage sensing segment of domain III, ...

  10. Mutations in the VNTR of the carboxyl-ester lipase gene (CEL) are a rare cause of monogenic diabetes.

    Science.gov (United States)

    Torsvik, Janniche; Johansson, Stefan; Johansen, Anders; Ek, Jakob; Minton, Jayne; Raeder, Helge; Ellard, Sian; Hattersley, Andrew; Pedersen, Oluf; Hansen, Torben; Molven, Anders; Njølstad, Pål R

    2010-01-01

    We have previously shown that heterozygous single-base deletions in the carboxyl-ester lipase (CEL) gene cause exocrine and endocrine pancreatic dysfunction in two multigenerational families. These deletions were found in the first and fourth repeats of a variable number of tandem repeats (VNTR), which has proven challenging to sequence due to high GC-content and considerable length variation. We have therefore developed a screening method consisting of a multiplex PCR followed by fragment analysis. The method detected putative disease-causing insertions and deletions in the proximal repeats of the VNTR, and determined the VNTR-length of each allele. When blindly testing 56 members of the two families with known single-base deletions in the CEL VNTR, the method correctly assessed the mutation carriers. Screening of 241 probands from suspected maturity-onset diabetes of the young (MODY) families negative for mutations in known MODY genes (95 individuals from Denmark and 146 individuals from UK) revealed no deletions in the proximal repeats of the CEL VNTR. However, we found one Danish patient with a short, novel CEL allele containing only three VNTR repeats (normal range 7-23 in healthy controls). This allele co-segregated with diabetes or impaired glucose tolerance in the patient's family as six of seven mutation carriers were affected. We also identified individuals who had three copies of a complete CEL VNTR. In conclusion, the CEL gene is highly polymorphic, but mutations in CEL are likely to be a rare cause of monogenic diabetes.

  11. Congenital Hypothyroidism Caused by a PAX8 Gene Mutation Manifested as Sodium/Iodide Symporter Gene Defect

    Directory of Open Access Journals (Sweden)

    Wakako Jo

    2010-01-01

    Full Text Available Loss-of-function mutations of the PAX8 gene are considered to mainly cause congenital hypothyroidism (CH due to thyroid hypoplasia. However, some patients with PAX8 mutation have demonstrated a normal-sized thyroid gland. Here we report a CH patient caused by a PAX8 mutation, which manifested as iodide transport defect (ITD. Hypothyroidism was detected by neonatal screening and L-thyroxine replacement was started immediately. Although 123I scintigraphy at 5 years of age showed that the thyroid gland was in the normal position and of small size, his iodide trapping was low. The ratio of the saliva/plasma radioactive iodide was low. He did not have goiter; however laboratory findings suggested that he had partial ITD. Gene analyses showed that the sodium/iodide symporter (NIS gene was normal; instead, a mutation in the PAX8 gene causing R31H substitution was identified. The present report demonstrates that individuals with defective PAX8 can have partial ITD, and thus genetic analysis is useful for differential diagnosis.

  12. Mutations in GREB1L Cause Bilateral Kidney Agenesis in Humans and Mice.

    Science.gov (United States)

    De Tomasi, Lara; David, Pierre; Humbert, Camille; Silbermann, Flora; Arrondel, Christelle; Tores, Frédéric; Fouquet, Stéphane; Desgrange, Audrey; Niel, Olivier; Bole-Feysot, Christine; Nitschké, Patrick; Roume, Joëlle; Cordier, Marie-Pierre; Pietrement, Christine; Isidor, Bertrand; Khau Van Kien, Philippe; Gonzales, Marie; Saint-Frison, Marie-Hélène; Martinovic, Jelena; Novo, Robert; Piard, Juliette; Cabrol, Christelle; Verma, Ishwar C; Puri, Ratna; Journel, Hubert; Aziza, Jacqueline; Gavard, Laurent; Said-Menthon, Marie-Hélène; Heidet, Laurence; Saunier, Sophie; Jeanpierre, Cécile

    2017-11-02

    Congenital anomalies of the kidney and urinary tract (CAKUT) constitute a major cause of chronic kidney disease in children and 20% of prenatally detected anomalies. CAKUT encompass a spectrum of developmental kidney defects, including renal agenesis, hypoplasia, and cystic and non-cystic dysplasia. More than 50 genes have been reported as mutated in CAKUT-affected case subjects. However, the pathophysiological mechanisms leading to bilateral kidney agenesis (BKA) remain largely elusive. Whole-exome or targeted exome sequencing of 183 unrelated familial and/or severe CAKUT-affected case subjects, including 54 fetuses with BKA, led to the identification of 16 heterozygous variants in GREB1L (growth regulation by estrogen in breast cancer 1-like), a gene reported as a target of retinoic acid signaling. Four loss-of-function and 12 damaging missense variants, 14 being absent from GnomAD, were identified. Twelve of them were present in familial or simplex BKA-affected case subjects. Female BKA-affected fetuses also displayed uterus agenesis. We demonstrated a significant association between GREB1L variants and BKA. By in situ hybridization, we showed expression of Greb1l in the nephrogenic zone in developing mouse kidney. We generated a Greb1l knock-out mouse model by CRISPR-Cas9. Analysis at E13.5 revealed lack of kidneys and genital tract anomalies in male and female Greb1l -/- embryos and a slight decrease in ureteric bud branching in Greb1l +/- embryos. We showed that Greb1l invalidation in mIMCD3 cells affected tubulomorphogenesis in 3D-collagen culture, a phenotype rescued by expression of the wild-type human protein. This demonstrates that GREB1L plays a major role in early metanephros and genital development in mice and humans. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  13. Mutations in EBF3 Disturb Transcriptional Profiles and Cause Intellectual Disability, Ataxia, and Facial Dysmorphism.

    Science.gov (United States)

    Harms, Frederike Leonie; Girisha, Katta M; Hardigan, Andrew A; Kortüm, Fanny; Shukla, Anju; Alawi, Malik; Dalal, Ashwin; Brady, Lauren; Tarnopolsky, Mark; Bird, Lynne M; Ceulemans, Sophia; Bebin, Martina; Bowling, Kevin M; Hiatt, Susan M; Lose, Edward J; Primiano, Michelle; Chung, Wendy K; Juusola, Jane; Akdemir, Zeynep C; Bainbridge, Matthew; Charng, Wu-Lin; Drummond-Borg, Margaret; Eldomery, Mohammad K; El-Hattab, Ayman W; Saleh, Mohammed A M; Bézieau, Stéphane; Cogné, Benjamin; Isidor, Bertrand; Küry, Sébastien; Lupski, James R; Myers, Richard M; Cooper, Gregory M; Kutsche, Kerstin

    2017-01-05

    From a GeneMatcher-enabled international collaboration, we identified ten individuals affected by intellectual disability, speech delay, ataxia, and facial dysmorphism and carrying a deleterious EBF3 variant detected by whole-exome sequencing. One 9-bp duplication and one splice-site, five missense, and two nonsense variants in EBF3 were found; the mutations occurred de novo in eight individuals, and the missense variant c.625C>T (p.Arg209Trp) was inherited by two affected siblings from their healthy mother, who is mosaic. EBF3 belongs to the early B cell factor family (also known as Olf, COE, or O/E) and is a transcription factor involved in neuronal differentiation and maturation. Structural assessment predicted that the five amino acid substitutions have damaging effects on DNA binding of EBF3. Transient expression of EBF3 mutant proteins in HEK293T cells revealed mislocalization of all but one mutant in the cytoplasm, as well as nuclear localization. By transactivation assays, all EBF3 mutants showed significantly reduced or no ability to activate transcription of the reporter gene CDKN1A, and in situ subcellular fractionation experiments demonstrated that EBF3 mutant proteins were less tightly associated with chromatin. Finally, in RNA-seq and ChIP-seq experiments, EBF3 acted as a transcriptional regulator, and mutant EBF3 had reduced genome-wide DNA binding and gene-regulatory activity. Our findings demonstrate that variants disrupting EBF3-mediated transcriptional regulation cause intellectual disability and developmental delay and are present in ∼0.1% of individuals with unexplained neurodevelopmental disorders. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  14. Focal palmoplantar keratoderma caused by an autosomal dominant inherited mutation in the desmoglein 1 gene

    NARCIS (Netherlands)

    Milingou, M; Wood, P; Masouye, [No Value; McLean, WH; Borradori, L

    2006-01-01

    Background: Palmoplantar keratodermas (PPK) encompass a large genetically heterogeneous group of diseases associated with hyperkeratosis of the soles and/or palms that occur either isolated or in association with other cutaneous and extracutaneous manifestations. Pathogenic mutations in the

  15. Mutations in SPRTN cause early onset hepatocellular carcinoma, genomic instability and progeroid features

    NARCIS (Netherlands)

    Lessel, Davor; Vaz, Bruno; Halder, Swagata; Lockhart, Paul J.; Marinovic-Terzic, Ivana; Lopez-Mosqueda, Jaime; Philipp, Melanie; Sim, Joe C. H.; Smith, Katherine R.; Oehler, Judith; Cabrera, Elisa; Freire, Raimundo; Pope, Kate; Nahid, Amsha; Norris, Fiona; Leventer, Richard J.; Delatycki, Martin B.; Barbi, Gotthold; von Ameln, Simon; Högel, Josef; Degoricija, Marina; Fertig, Regina; Burkhalter, Martin D.; Hofmann, Kay; Thiele, Holger; Altmüller, Janine; Nürnberg, Gudrun; Nürnberg, Peter; Bahlo, Melanie; Martin, George M.; Aalfs, Cora M.; Oshima, Junko; Terzic, Janos; Amor, David J.; Dikic, Ivan; Ramadan, Kristijan; Kubisch, Christian

    2014-01-01

    Age-related degenerative and malignant diseases represent major challenges for health care systems. Elucidation of the molecular mechanisms underlying carcinogenesis and age-associated pathologies is thus of growing biomedical relevance. We identified biallelic germline mutations in SPRTN (also

  16. Desmin mutations as a cause of right ventricular heart failure affect the intercalated disks

    NARCIS (Netherlands)

    Otten, Ellen; Asimaki, Angeliki; Maass, Alexander; van Langen, Irene M.; van der Wal, Allard; de Jonge, Nicolaas; van den Berg, Maarten P.; Saffitz, Jeffrey E.; Wilde, Arthur A. M.; Jongbloed, Jan D. H.; van Tintelen, J. Peter

    BACKGROUND Mutations in the gene encoding desmin (DES), an intermediate filament protein, underlie a heterogeneous phenotype, which is referred to as desmin-related myopathy (DRM). Right ventricular involvement including an arrhythmogenic right ventricular cardiomyopathy (ARVC)(-like) phenotype has

  17. Desmin mutations as a cause of right ventricular heart failure affect the intercalated disks

    NARCIS (Netherlands)

    Otten, Ellen; Asimaki, Angeliki; Maass, Alexander; van Langen, Irene M.; van der Wal, Allard; de Jonge, Nicolaas; van den Berg, Maarten P.; Saffitz, Jeffrey E.; Wilde, Arthur A. M.; Jongbloed, Jan D. H.; van Tintelen, J. Peter

    2010-01-01

    BACKGROUND Mutations in the gene encoding desmin (DES), an intermediate filament protein, underlie a heterogeneous phenotype, which is referred to as desmin-related myopathy (DRM). Right ventricular involvement including an arrhythmogenic right ventricular cardiomyopathy (ARVC)(-like) phenotype has

  18. Phenotypic Conservation in Patients With X-Linked Retinitis Pigmentosa Caused by RPGR Mutations

    Science.gov (United States)

    Zahid, Sarwar; Khan, Naheed; Branham, Kari; Othman, Mohammad; Karoukis, Athanasios J.; Sharma, Nisha; Moncrief, Ashley; Mahmood, Mahdi N.; Sieving, Paul A.; Swaroop, Anand; Heckenlively, John R.; Jayasundera, Thiran

    2015-01-01

    IMPORTANCE For patients with X-linked retinitis pigmentosa and clinicians alike, phenotypic variability can be challenging because it complicates counseling regarding patients’ likely visual prognosis. OBJECTIVE To evaluate the clinical findings from patients with X-linked retinitis pigmentosa with 13 distinct RPGR mutations and assess for phenotypic concordance or variability. DESIGN Retrospective medical record review of data collected from 1985 to 2011. SETTING Kellogg Eye Center, University of Michigan. PATIENTS A total of 42 patients with X-linked retinitis pigmentosa with mutations in RPGR. Age at first visit ranged from 4 to 53 years, with follow-up ranging from 1 to 11 visits (median follow-up time, 5.5 years; range, 1.4-32.7 years, for 23 patients with >1 visit). MAIN OUTCOMES AND MEASURES Clinical data assessed for concordance included visual acuity (VA), Goldmann visual fields (GVFs), and full-field electroretinography (ERG). Electroretinography phenotype (cone-rod vs rod-cone dysfunction) was defined by the extent of photopic vs scotopic abnormality. Qualitative GVF phenotype was determined by the GVF pattern, where central or peripheral loss suggested cone or rod dysfunction, respectively. Goldmann visual fields were also quantified and compared among patients. RESULTS Each mutation was detected in 2 or more related or unrelated patients. Five mutations in 11 patients displayed strong concordance of VA, while 4 mutations in 16 patients revealed moderate concordance of VA. A definitive cone-rod or rod-cone ERG pattern consistent among patients was found in 6 of 13 mutations (46.2%); the remaining mutations were characterized by patients demonstrating both phenotypes or who had limited data or nonrecordable ERG values. Concordant GVF phenotypes (7 rod-cone pattern vs 4 cone-rod pattern) were seen in 11 of 13 mutations (84.6%). All 6 mutations displaying a constant ERG pattern within the mutation group revealed a GVF phenotype consistent with the ERG

  19. Non-DNA binding, dominant-negative, human PPARγ mutations cause lipodystrophic insulin resistance

    OpenAIRE

    Agostini, Maura; Schoenmakers, Erik; Mitchell, Catherine; Szatmari, Istvan; Savage, David; Smith, Aaron; Rajanayagam, Odelia; Semple, Robert; Luan, Jian'an; Bath, Louise; Zalin, Anthony; Labib, Mourad; Kumar, Sudhesh; Simpson, Helen; Blom, Dirk

    2006-01-01

    PPARgamma is essential for adipogenesis and metabolic homeostasis. We describe mutations in the DNA and ligand binding domains of human PPARgamma in lipodystrophic, severe insulin resistance. These receptor mutants lack DNA binding and transcriptional activity but can translocate to the nucleus, interact with PPARgamma coactivators and inhibit coexpressed wild-type receptor. Expression of PPARgamma target genes is markedly attenuated in mutation-containing versus receptor haploinsufficent pri...

  20. Cantú Syndrome Is Caused by Mutations in ABCC9

    OpenAIRE

    van Bon, Bregje W.M.; Gilissen, Christian; Grange, Dorothy K.; Hennekam, Raoul C.M.; Kayserili, Hülya; Engels, Hartmut; Reutter, Heiko; Ostergaard, John R.; Morava, Eva; Tsiakas, Konstantinos; Isidor, Bertrand; Le Merrer, Martine; Eser, Metin; Wieskamp, Nienke; de Vries, Petra

    2012-01-01

    Cantú syndrome is a rare disorder characterized by congenital hypertrichosis, neonatal macrosomia, a distinct osteochondrodysplasia, and cardiomegaly. Using an exome-sequencing approach applied to one proband-parent trio and three unrelated single cases, we identified heterozygous mutations in ABCC9 in all probands. With the inclusion of the remaining cohort of ten individuals with Cantú syndrome, a total of eleven mutations in ABCC9 were found. The de novo occurrence in all six simplex cases...

  1. Mutations in the Matrin 3 gene cause familial amyotrophic lateral sclerosis.

    Science.gov (United States)

    Johnson, Janel O; Pioro, Erik P; Boehringer, Ashley; Chia, Ruth; Feit, Howard; Renton, Alan E; Pliner, Hannah A; Abramzon, Yevgeniya; Marangi, Giuseppe; Winborn, Brett J; Gibbs, J Raphael; Nalls, Michael A; Morgan, Sarah; Shoai, Maryam; Hardy, John; Pittman, Alan; Orrell, Richard W; Malaspina, Andrea; Sidle, Katie C; Fratta, Pietro; Harms, Matthew B; Baloh, Robert H; Pestronk, Alan; Weihl, Conrad C; Rogaeva, Ekaterina; Zinman, Lorne; Drory, Vivian E; Borghero, Giuseppe; Mora, Gabriele; Calvo, Andrea; Rothstein, Jeffrey D; Drepper, Carsten; Sendtner, Michael; Singleton, Andrew B; Taylor, J Paul; Cookson, Mark R; Restagno, Gabriella; Sabatelli, Mario; Bowser, Robert; Chiò, Adriano; Traynor, Bryan J

    2014-05-01

    MATR3 is an RNA- and DNA-binding protein that interacts with TDP-43, a disease protein linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Using exome sequencing, we identified mutations in MATR3 in ALS kindreds. We also observed MATR3 pathology in ALS-affected spinal cords with and without MATR3 mutations. Our data provide more evidence supporting the role of aberrant RNA processing in motor neuron degeneration.

  2. De novo nonsense mutations in ASXL1 cause Bohring-Opitz syndrome

    DEFF Research Database (Denmark)

    Hoischen, Alexander; van Bon, Bregje W M; Rodríguez-Santiago, Benjamín

    2011-01-01

    Bohring-Opitz syndrome is characterized by severe intellectual disability, distinctive facial features and multiple congenital malformations. We sequenced the exomes of three individuals with Bohring-Opitz syndrome and in each identified heterozygous de novo nonsense mutations in ASXL1, which...... is required for maintenance of both activation and silencing of Hox genes. In total, 7 out of 13 subjects with a Bohring-Opitz phenotype had de novo ASXL1 mutations, suggesting that the syndrome is genetically heterogeneous....

  3. Clinical and Prognostic Profiles of Cardiomyopathies Caused by Mutations in the Troponin T Gene.

    Science.gov (United States)

    Ripoll-Vera, Tomás; Gámez, José María; Govea, Nancy; Gómez, Yolanda; Núñez, Juana; Socías, Lorenzo; Escandell, Ángela; Rosell, Jorge

    2016-02-01

    Mutations in the troponin T gene (TTNT2) have been associated in small studies with the development of hypertrophic cardiomyopathy characterized by a high risk of sudden death and mild hypertrophy. We describe the clinical course of patients carrying mutations in this gene. We analyzed the clinical characteristics and prognosis of patients with mutations in the TNNT2 gene who were seen in an inherited cardiac disease unit. Of 180 families with genetically studied cardiomyopathies, 21 families (11.7%) were identified as having mutations in TNNT2: 10 families had Arg92Gln, 5 had Arg286His, 3 had Arg278Cys, 1 had Arg92Trp, 1 had Arg94His, and 1 had Ile221Thr. Thirty-three additional genetic carriers were identified through family assessment. The study included 54 genetic carriers: 56% were male, and the mean average age was 41 ± 17 years. There were 33 cases of hypertrophic cardiomyopathy, 9 of dilated cardiomyopathy, and 1 of noncompaction cardiomyopathy, and maximal myocardial thickness was 18.5 ± 6mm. Ventricular dysfunction was present in 30% of individuals and a history of sudden death in 62%. During follow-up, 4 patients died and 14 (33%) received a defibrillator (8 probands, 6 relatives). Mean survival was 54 years. Carriers of Arg92Gln had early disease development, high penetrance, a high risk of sudden death, a high rate of defibrillator implantation, and a high frequency of mixed phenotype. Mutations in the TNNT2 gene were more common in this series than in previous studies. The clinical and prognostic profiles depended on the mutation present. Carriers of the Arg92Gln mutation developed hypertrophic or dilated cardiomyopathy and had a significantly worse prognosis than those with other mutations in TNNT2 or other sarcomeric genes. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  4. A single point-mutation within the melanophilin gene causes the lavender plumage colour dilution phenotype in the chicken

    Directory of Open Access Journals (Sweden)

    Tixier-Boichard Michèle

    2008-01-01

    Full Text Available Abstract Background The lavender phenotype in the chicken causes the dilution of both black (eumelanin and red/brown (phaeomelanin pigments. Defects in three genes involved in intracellular melanosomal transport, previously described in mammals, give rise to similar diluted pigmentation phenotypes as those seen in lavender chickens. Results We have used a candidate-gene approach based on an expectation of homology with mammals to isolate a gene involved in pigmentation in chicken. Comparative sequence analysis of candidate genes in the chicken identified a strong association between a mutation in the MLPH gene and the diluted pigmentation phenotype. This mutation results in the amino acid change R35W, at a site also associated with similar phenotypes in mice, humans and cats. Conclusion This is the first time that an avian species with a mutation in the MLPH gene has been reported.

  5. A cis-acting regulatory mutation causes premature hair graying and susceptibility to melanoma in the horse.

    Science.gov (United States)

    Rosengren Pielberg, Gerli; Golovko, Anna; Sundström, Elisabeth; Curik, Ino; Lennartsson, Johan; Seltenhammer, Monika H; Druml, Thomas; Binns, Matthew; Fitzsimmons, Carolyn; Lindgren, Gabriella; Sandberg, Kaj; Baumung, Roswitha; Vetterlein, Monika; Strömberg, Sara; Grabherr, Manfred; Wade, Claire; Lindblad-Toh, Kerstin; Pontén, Fredrik; Heldin, Carl-Henrik; Sölkner, Johann; Andersson, Leif

    2008-08-01

    In horses, graying with age is an autosomal dominant trait associated with a high incidence of melanoma and vitiligo-like depigmentation. Here we show that the Gray phenotype is caused by a 4.6-kb duplication in intron 6 of STX17 (syntaxin-17) that constitutes a cis-acting regulatory mutation. Both STX17 and the neighboring NR4A3 gene are overexpressed in melanomas from Gray horses. Gray horses carrying a loss-of-function mutation in ASIP (agouti signaling protein) had a higher incidence of melanoma, implying that increased melanocortin-1 receptor signaling promotes melanoma development in Gray horses. The Gray horse provides a notable example of how humans have cherry-picked mutations with favorable phenotypic effects in domestic animals.

  6. EDNRB mutations cause Waardenburg syndrome type II in the heterozygous state.

    Science.gov (United States)

    Issa, Sarah; Bondurand, Nadege; Faubert, Emmanuelle; Poisson, Sylvain; Lecerf, Laure; Nitschke, Patrick; Deggouj, Naima; Loundon, Natalie; Jonard, Laurence; David, Albert; Sznajer, Yves; Blanchet, Patricia; Marlin, Sandrine; Pingault, Veronique

    2017-05-01

    Waardenburg syndrome (WS) is a genetic disorder characterized by sensorineural hearing loss and pigmentation anomalies. The clinical definition of four WS types is based on additional features due to defects in structures mostly arising from the neural crest, with type I and type II being the most frequent. While type I is tightly associated to PAX3 mutations, WS type II (WS2) remains partly enigmatic with mutations in known genes (MITF, SOX10) accounting for only 30% of the cases. We performed exome sequencing in a WS2 index case and identified a heterozygous missense variation in EDNRB. Interestingly, homozygous (and very rare heterozygous) EDNRB mutations are already described in type IV WS (i.e., in association with Hirschsprung disease [HD]) and heterozygous mutations in isolated HD. Screening of a WS2 cohort led to the identification of an overall of six heterozygous EDNRB variations. Clinical phenotypes, pedigrees and molecular segregation investigations unraveled a dominant mode of inheritance with incomplete penetrance. In parallel, cellular and functional studies showed that each of the mutations impairs the subcellular localization of the receptor or induces a defective downstream signaling pathway. Based on our results, we now estimate EDNRB mutations to be responsible for 5%-6% of WS2. © 2017 Wiley Periodicals, Inc.

  7. Loss-of-function CARD8 mutation causes NLRP3 inflammasome activation and Crohn's disease.

    Science.gov (United States)

    Mao, Liming; Kitani, Atsushi; Similuk, Morgan; Oler, Andrew J; Albenberg, Lindsey; Kelsen, Judith; Aktay, Atiye; Quezado, Martha; Yao, Michael; Montgomery-Recht, Kim; Fuss, Ivan J; Strober, Warren

    2018-02-06

    In these studies we evaluated the contribution of the NLRP3 inflammasome to Crohn's disease (CD) in a kindred containing individuals having a missense mutation in CARD8, a protein known to inhibit this inflammasome. Whole exome sequencing and PCR studies identified that the affected individuals had a V44I mutation in a single allele of the T60 isoform of CARD8. The serum levels of IL-1β in the affected individuals were increased compared with that in healthy controls and their peripheral monocytes produced increased amounts of IL-1β when stimulated by NLRP3 activators. Immunoblot studies probing the basis of these findings showed that mutated T60 CARD8 fails to down-regulate the NLRP3 inflammasome because it does not bind to NLRP3 and inhibit its oligomerization. In addition, these studies showed that mutated T60 CARD8 exerts a dominant negative effect by its capacity to bind to and form oligomers with unmutated T60 or T48 CARD8 that impede their binding to NLRP3. Finally, inflammasome activation studies revealed that intact but not mutated CARD8 prevents NLRP3 deubiquitination and serine dephosphorylation. CD due to a CARD8 mutation was not effectively treated by anti-TNF-α, but did respond to IL-1β inhibitors. Thus, patients with anti-TNF-α-resistant CD may respond to this treatment option.

  8. Homozygosity Mapping Reveals Mutations of GRXCR1 as a Cause of Autosomal-Recessive Nonsyndromic Hearing Impairment

    Science.gov (United States)

    Schraders, Margit; Lee, Kwanghyuk; Oostrik, Jaap; Huygen, Patrick L.M.; Ali, Ghazanfar; Hoefsloot, Lies H.; Veltman, Joris A.; Cremers, Frans P.M.; Basit, Sulman; Ansar, Muhammad; Cremers, Cor W.R.J.; Kunst, Henricus P.M.; Ahmad, Wasim; Admiraal, Ronald J.C.; Leal, Suzanne M.; Kremer, Hannie

    2010-01-01

    We identified overlapping homozygous regions within the DFNB25 locus in two Dutch and ten Pakistani families with sensorineural autosomal-recessive nonsyndromic hearing impairment (arNSHI). Only one of the families, W98-053, was not consanguineous, and its sibship pointed toward a reduced critical region of 0.9 Mb. This region contained the GRXCR1 gene, and the orthologous mouse gene was described to be mutated in the pirouette (pi) mutant with resulting hearing loss and circling behavior. Sequence analysis of the GRXCR1 gene in hearing-impaired family members revealed splice-site mutations in two Dutch families and a missense and nonsense mutation, respectively, in two Pakistani families. The splice-site mutations are predicted to cause frameshifts and premature stop codons. In family W98-053, this could be confirmed by cDNA analysis. GRXCR1 is predicted to contain a GRX-like domain. GRX domains are involved in reversible S-glutathionylation of proteins and thereby in the modulation of activity and/or localization of these proteins. The missense mutation is located in this domain, whereas the nonsense and splice-site mutations may result in complete or partial absence of the GRX-like domain or of the complete protein. Hearing loss in patients with GRXCR1 mutations is congenital and is moderate to profound. Progression of the hearing loss was observed in family W98-053. Vestibular dysfunction was observed in some but not all affected individuals. Quantitative analysis of GRXCR1 transcripts in fetal and adult human tissues revealed a preferential expression of the gene in fetal cochlea, which may explain the nonsyndromic nature of the hearing impairment. PMID:20137778

  9. A case report of novel mutation in PRF1 gene, which causes familial autosomal recessive hemophagocytic lymphohistiocytosis.

    Science.gov (United States)

    Bordbar, Mohammad Reza; Modarresi, Farzaneh; Farazi Fard, Mohammad Ali; Dastsooz, Hassan; Shakib Azad, Nader; Faghihi, Mohammad Ali

    2017-05-03

    Hemophagocytic Lymphohistiocytosis (HLH) is a life-threatening immunodeficiency and multi-organ disease that affects people of all ages and ethnic groups. Common symptoms and signs of this disease are high fever, hepatosplenomegaly, and cytopenias. Familial form of HLH disease, which is an autosomal recessive hematological disorder is due to disease-causing mutations in several genes essential for NK and T-cell granule-mediated cytotoxic function. For an effective cytotoxic response from cytotoxic T lymphocyte or NK cell encountering an infected cell or tumor cell, different processes are required, including trafficking, docking, priming, membrane fusion, and entry of cytotoxic granules into the target cell leading to apoptosis. Therefore, genes involved in these steps play important roles in the pathogenesis of HLH disease which include PRF1, UNC13D (MUNC13-4), STX11, and STXBP2 (MUNC18-2). Here, we report a novel missense mutation in an 8-year-old boy suffered from hepatosplenomegaly, hepatitis, epilepsy and pancytopenia. The patient was born to a first-cousin parents with no previous documented disease in his parents. To identify mutated gene in the proband, Whole Exome Sequencing (WES) utilizing next generation sequencing was used on an Illumina HiSeq 2000 platform on DNA sample from the patient. Results showed a novel deleterious homozygous missense mutation in PRF1 gene (NM_001083116: exon3: c. 1120 T > G, p.W374G) in the patient and then using Sanger sequencing it was confirmed in the proband and his parents. Since his parents were heterozygous for the identified mutation, autosomal recessive pattern of inheritance was confirmed in the family. Our study identified a rare new pathogenic missense mutation in PRF1 gene in patient with HLH disease and it is the first report of mutation in PRF1 in Iranian patients with this disease.

  10. Colon cancer-associated mutator DNA polymerase δ variant causes expansion of dNTP pools increasing its own infidelity

    Science.gov (United States)

    Mertz, Tony M.; Sharma, Sushma; Chabes, Andrei; Shcherbakova, Polina V.

    2015-01-01

    Defects in DNA polymerases δ (Polδ) and ε (Polε) cause hereditary colorectal cancer and have been implicated in the etiology of some sporadic colorectal and endometrial tumors. We previously reported that the yeast pol3-R696W allele mimicking a human cancer-associated variant, POLD1-R689W, causes a catastrophic increase in spontaneous mutagenesis. Here, we describe the mechanism of this extraordinary mutator effect. We found that the mutation rate increased synergistically when the R696W mutation was combined with defects in Polδ proofreading or mismatch repair, indicating that pathways correcting DNA replication errors are not compromised in pol3-R696W mutants. DNA synthesis by purified Polδ-R696W was error-prone, but not to the extent that could account for the unprecedented mutator phenotype of pol3-R696W strains. In a search for cellular factors that augment the mutagenic potential of Polδ-R696W, we discovered that pol3-R696W causes S-phase checkpoint-dependent elevation of dNTP pools. Abrogating this elevation by strategic mutations in dNTP metabolism genes eliminated the mutator effect of pol3-R696W, whereas restoration of high intracellular dNTP levels restored the mutator phenotype. Further, the use of dNTP concentrations present in pol3-R696W cells for in vitro DNA synthesis greatly decreased the fidelity of Polδ-R696W and produced a mutation spectrum strikingly similar to the spectrum observed in vivo. The results support a model in which (i) faulty synthesis by Polδ-R696W leads to a checkpoint-dependent increase in dNTP levels and (ii) this increase mediates the hypermutator effect of Polδ-R696W by facilitating the extension of mismatched primer termini it creates and by promoting further errors that continue to fuel the mutagenic pathway. PMID:25827231

  11. Biallelic mutations in DYNC2LI1 are a rare cause of Ellis-van Creveld syndrome.

    Science.gov (United States)

    Niceta, M; Margiotti, K; Digilio, M C; Guida, V; Bruselles, A; Pizzi, S; Ferraris, A; Memo, L; Laforgia, N; Dentici, M L; Consoli, F; Torrente, I; Ruiz-Perez, V L; Dallapiccola, B; Marino, B; De Luca, A; Tartaglia, M

    2018-03-01

    Ellis-van Creveld syndrome (EvC) is a chondral and ectodermal dysplasia caused by biallelic mutations in the EVC, EVC2 and WDR35 genes. A proportion of cases with clinical diagnosis of EvC, however, do not carry mutations in these genes. To identify the genetic cause of EvC in a cohort of mutation-negative patients, exome sequencing was undertaken in a family with 3 affected members, and mutation scanning of a panel of clinically and functionally relevant genes was performed in 24 additional subjects with features fitting/overlapping EvC. Compound heterozygosity for the c.2T>C (p.Met1?) and c.662C>T (p.Thr221Ile) variants in DYNC2LI1, which encodes a component of the intraflagellar transport-related dynein-2 complex previously found mutated in other short-rib thoracic dysplasias, was identified in the 3 affected members of the first family. Targeted resequencing detected compound heterozygosity for the same missense variant and a truncating change (p.Val141*) in 2 siblings with EvC from a second family, while a newborn with a more severe phenotype carried 2 DYNC2LI1 truncating variants. Our findings indicate that DYNC2LI1 mutations are associated with a wider clinical spectrum than previously appreciated, including EvC, with the severity of the phenotype likely depending on the extent of defective DYNC2LI1 function. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Mutations in RIT1 cause Noonan syndrome with possible juvenile myelomonocytic leukemia but are not involved in acute lymphoblastic leukemia.

    Science.gov (United States)

    Cavé, Hélène; Caye, Aurélie; Ghedira, Nehla; Capri, Yline; Pouvreau, Nathalie; Fillot, Natacha; Trimouille, Aurélien; Vignal, Cédric; Fenneteau, Odile; Alembik, Yves; Alessandri, Jean-Luc; Blanchet, Patricia; Boute, Odile; Bouvagnet, Patrice; David, Albert; Dieux Coeslier, Anne; Doray, Bérénice; Dulac, Olivier; Drouin-Garraud, Valérie; Gérard, Marion; Héron, Delphine; Isidor, Bertrand; Lacombe, Didier; Lyonnet, Stanislas; Perrin, Laurence; Rio, Marlène; Roume, Joëlle; Sauvion, Sylvie; Toutain, Annick; Vincent-Delorme, Catherine; Willems, Marjorie; Baumann, Clarisse; Verloes, Alain

    2016-08-01

    Noonan syndrome is a heterogeneous autosomal dominant disorder caused by mutations in at least eight genes involved in the RAS/MAPK signaling pathway. Recently, RIT1 (Ras-like without CAAX 1) has been shown to be involved in the pathogenesis of some patients. We report a series of 44 patients from 30 pedigrees (including nine multiplex families) with mutations in RIT1. These patients display a typical Noonan gestalt and facial phenotype. Among the probands, 8.7% showed postnatal growth retardation, 90% had congenital heart defects, 36% had hypertrophic cardiomyopathy (a lower incidence compared with previous report), 50% displayed speech delay and 52% had learning difficulties, but only 22% required special education. None had major skin anomalies. One child died perinatally of juvenile myelomonocytic leukemia. Compared with the canonical Noonan phenotype linked to PTPN11 mutations, patients with RIT1 mutations appear to be less severely growth retarded and more frequently affected by cardiomyopathy. Based on our experience, we estimate that RIT1 could be the cause of 5% of Noonan syndrome patients. Because mutations found constitutionally in Noonan syndrome are also found in several tumors in adulthood, we evaluated the potential contribution of RIT1 to leukemogenesis in Noonan syndrome. We screened 192 pediatric cases of acute lymphoblastic leukemias (96 B-ALL and 96 T-ALL) and 110 cases of juvenile myelomonocytic leukemias (JMML), but detected no variation in these tumoral samples, suggesting that Noonan patients with germline RIT1 mutations are not at high risk to developing JMML or ALL, and that RIT1 has at most a marginal role in these sporadic malignancies.

  13. Mild thyroid peroxidase deficiency caused by TPO mutations with residual activity: Correlation between clinical phenotypes and enzymatic activity.

    Science.gov (United States)

    Narumi, Satoshi; Fox, Larry A; Fukudome, Keisuke; Sakaguchi, Zenichi; Sugisawa, Chiho; Abe, Kiyomi; Kameyama, Kaori; Hasegawa, Tomonobu

    2017-11-29

    Thyroid peroxidase (TPO) deficiency, caused by biallelic TPO mutations, is a well-established genetic form of congenital hypothyroidism (CH). More than 100 patients have been published, and the patients have been diagnosed mostly in the frame of newborn screening (NBS) programs. Correlation between clinical phenotypes and TPO activity remains unclear. Here, we report clinical and molecular findings of two unrelated TPO mutation-carrying mildly hypothyroid patients. The two patients were born at term after an uneventful pregnancy and delivery, and were NBS negative. They sought medical attention due to goiter at age 8 years. Evaluation of the thyroid showed mild elevation of serum TSH levels, normal or slightly low serum T 4 levels, high serum T 3 to T 4 molar ratio, high serum thyroglobulin levels, and high thyroidal 123 I uptake. We performed next-generation sequencing-based genetic screening, and found that one patient was compound heterozygous for two novel TPO mutations (p.Asp224del; c.820-2A>G), and the other was homozygous for a previously known mutation (p.Trp527Cys). In vitro functional analyses using HEK293 cells showed that the two amino acid-altering mutations (p.Asp224del and p.Trp527Cys) caused partial loss of the enzymatic activity. In conclusion, we report that TPO mutations with residual activity are associated with mild TPO deficiency, which is clinically characterized by marked goiter, mild TSH elevation, high serum T 3 to T 4 molar ratio, and high serum thyroglobulin levels. Our findings illuminate the hitherto under-recognized correlation between clinical phenotypes and residual enzymatic activity among patients with TPO deficiency.

  14. Coffin-Siris Syndrome with obesity, macrocephaly, hepatomegaly and hyperinsulinism caused by a mutation in the ARID1B gene.

    Science.gov (United States)

    Vals, Mari-Anne; Õiglane-Shlik, Eve; Nõukas, Margit; Shor, Riina; Peet, Aleksandr; Kals, Mart; Kivistik, Paula Ann; Metspalu, Andres; Õunap, Katrin

    2014-11-01

    Coffin-Siris Syndrome (CSS, MIM 135900) is a rare genetic disorder, and mutations in ARID1B were recently shown to cause CSS. In this study, we report a novel ARID1B mutation identified by whole-exome sequencing in a patient with clinical features of CSS. We identified a novel heterozygous frameshift mutation c.1584delG in exon 2 of ARID1B (NM_020732.3) predicting a premature stop codon p.(Leu528Phefs*65). Sanger sequencing confirmed the c.1584delG mutation as a de novo in the proband and that it was not present either in her parents, half-sister or half-brother. Clinically, the patient presented with extreme obesity, macrocephaly, hepatomegaly, hyperinsulinism and polycystic ovarian syndrome (PCOS), which have previously not been described in CSS patients. We suggest that obesity, macrocephaly, hepatomegaly and/or PCOS may be added to the list of clinical features of ARID1B mutations, but further clinical reports are required to make a definite conclusion.

  15. Coffin–Siris Syndrome with obesity, macrocephaly, hepatomegaly and hyperinsulinism caused by a mutation in the ARID1B gene

    Science.gov (United States)

    Vals, Mari-Anne; Õiglane-Shlik, Eve; Nõukas, Margit; Shor, Riina; Peet, Aleksandr; Kals, Mart; Kivistik, Paula Ann; Metspalu, Andres; Õunap, Katrin

    2014-01-01

    Coffin–Siris Syndrome (CSS, MIM 135900) is a rare genetic disorder, and mutations in ARID1B were recently shown to cause CSS. In this study, we report a novel ARID1B mutation identified by whole-exome sequencing in a patient with clinical features of CSS. We identified a novel heterozygous frameshift mutation c.1584delG in exon 2 of ARID1B (NM_020732.3) predicting a premature stop codon p.(Leu528Phefs*65). Sanger sequencing confirmed the c.1584delG mutation as a de novo in the proband and that it was not present either in her parents, half-sister or half-brother. Clinically, the patient presented with extreme obesity, macrocephaly, hepatomegaly, hyperinsulinism and polycystic ovarian syndrome (PCOS), which have previously not been described in CSS patients. We suggest that obesity, macrocephaly, hepatomegaly and/or PCOS may be added to the list of clinical features of ARID1B mutations, but further clinical reports are required to make a definite conclusion. PMID:24569609

  16. A Novel non-sense Mutation in Keratin 10 Causes a Familial Case of Recessive Epidermolytic Ichthyosis.

    Science.gov (United States)

    Gutierrez, Jeydith A; Hannoush, Zeina C; Vargas, Luis G; Momany, Allison; Garcia, Carmen C; Murray, Jeffrey C; Dunnwald, Martine

    2013-07-01

    Epidermolytic ichthyosis (EI) is a rare skin disorder characterized by generalized erythroderma and cutaneous blistering at birth, which is substituted by hyperkeratosis later in life. It is caused by autosomal dominant mutations in highly conserved regions of KRT1 and KRT10 . To date, only 4 mutations with autosomal recessive inheritance of EI have been described in consanguineous families. All of them affect the 2B domain of KRT10 . In the present study we describe four patients with EI (including one lethal case) born from unaffected parents in a consanguineous family of a native Venezuelan community. The objective of this study was to characterize the clinical, genetic and morphological aspects of the disease in this family, as well as understand its functional implications. Genomic DNA was sequenced for KRT10 and KRT1. Immunofluoresence for keratin expression was performed on cutaneous biopsies. After examination of cutaneous biopsies histology, our results showed hyperkeratosis and acantholysis with an expanded granular layer. Sequencing of KRT10 demonstrated a non-sense mutation (p.Tyr282Ter.) corresponding to the 1B domain of the protein in patients and a heterozygous pattern in other family members, resulting in complete absence of K10. The loss of K10 was compensated by upregulation of K14 and K17. In conclusion, this novel mutation in KRT10 is the first recessive genetic variation that is not located in the so called "hot spot" for recessive EI, suggesting that other areas of the gene are also susceptible for such mutations.

  17. Autosomal recessive agammaglobulinemia due to defect in μ heavy chain caused by a novel mutation in the IGHM gene.

    Science.gov (United States)

    Silva, P; Justicia, A; Regueiro, A; Fariña, S; Couselo, J M; Loidi, L

    2017-09-01

    Agammaglobulinemia is a primary immunodeficiency disorder characterized by profoundly low or absent serum antibodies and low or absent circulating B cells. The most common form is X-linked agammaglobulinemia (XLA) caused by mutations in BTK gene. The remaining cases, clinically similar to XLA, are autosomal recessive agammaglobulinemia (ARA). Nearly 30% of ARA cases present mutations in the μ heavy constant region gene IGHM. Here, we present a 7-month-old patient, born from non-consanguineous parents, who is affected by ARA due to defect in the μ heavy chain. The genetic study showed that the patient is compound heterozygous for an IGHM gene deletion and the novel nonsense mutation X57331.1:g.275C>A (p.Tyr43*) (ClinVar Accession Number: SCV000537868.1). This finding allows for an adequate genetic counseling to the family and also broadens the spectrum of already described point mutations at this locus. The IGHM gene is very complex and it is likely that yet unidentified mutations appear in other patients.

  18. The first two confirmed sub-Saharan African families with germline TP53 mutations causing Li-Fraumeni syndrome.

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    Macaulay, Shelley; Goodyear, Quintin Clive; Kruger, Mia; Chen, Wenlong; Essop, Fahmida; Krause, Amanda

    2018-02-01

    Li-Fraumeni syndrome is a rare inherited cancer syndrome characterised by the early onset of specific cancers. Li-Fraumeni syndrome (LFS) is associated with germline mutations in the tumour suppressor gene, TP53. This study reports the first cases of molecularly confirmed LFS germline mutations in sub-Saharan Africa. Three black African patients, all with LFS-associated cancers, were seen through the Clinical and Counselling Section of the Division of Human Genetics at the National Health Laboratory Service and University of the Witwatersrand in Johannesburg, South Africa, during 2011-2012. All three patients (two were related) were recruited into this research study. Sequence analysis of the coding region of the TP53 gene identified a Class IV (likely pathogenic) variant, c.326T > C (p.Phe109Ser), in the two related patients, and a known pathogenic mutation, c.1010G > A (p.Arg337His), also referred to as the Brazilian founder mutation, in the other patient. A confirmed diagnosis in these patients will assist in tailored medical management (it is recommended that individuals carrying a germline TP53 mutation avoid radiotherapy as this might cause secondary radiotherapy-induced malignancies) and in addition, genetic testing of at-risk family members can be offered. Very little is known and documented on LFS in African individuals. Despite the small number of patients in this study, the results support the need for diagnostic genetic testing for LFS in South Africa.

  19. Phenotypic variability in patients with osteogenesis imperfecta caused by BMP1 mutations.

    Science.gov (United States)

    Pollitt, Rebecca C; Saraff, Vrinda; Dalton, Ann; Webb, Emma A; Shaw, Nick J; Sobey, Glenda J; Mughal, M Zulf; Hobson, Emma; Ali, Farhan; Bishop, Nicholas J; Arundel, Paul; Högler, Wolfgang; Balasubramanian, Meena

    2016-12-01

    Osteogenesis Imperfecta (OI) is an inherited bone fragility disorder most commonly associated with autosomal dominant mutations in the type I collagen genes. Autosomal recessive mutations in a number of genes have also been described, including the BMP1 gene that encodes the mammalian Tolloid (mTLD) and its shorter isoform bone morphogenic protein-1 (BMP1). To date, less than 20 individuals with OI have been identified with BMP1 mutations, with skeletal phenotypes ranging from mild to severe and progressively deforming. In the majority of patients, bone fragility was associated with increased bone mineral density (BMD); however, the full range of phenotypes associated with BMP1 remains unclear. Here, we describe three children with mutations in BMP1 associated with a highly variable phenotype: a sibship homozygous for the c.2188delC mutation that affects only the shorter BMP1 isoform and a further patient who is compound heterozygous for a c.1293C>G nonsense mutation and a c.1148G>A missense mutation in the CUB1 domain. These individuals had recurrent fractures from early childhood, are hypermobile and have no evidence of dentinogenesis imperfecta. The homozygous siblings with OI had normal areal BMD by dual energy X-ray absorptiometry whereas the third patient presented with a high bone mass phenotype. Intravenous bisphosphonate therapy was started in all patients, but discontinued in two patients and reduced in another due to concerns about increasing bone stiffness leading to chalk-stick fractures. Given the association of BMP1-related OI with very high bone material density, concerns remain whether anti-resorptive therapy is indicated in this ultra-rare form of OI.© 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Detection of fetal mutations causing hemoglobinopathies by non-invasive prenatal diagnosis from maternal plasma

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    E D′Souza

    2013-01-01

    Full Text Available Background: Prenatal diagnosis of hemoglobinopathies enables couples at risk to have a healthy child. Currently used fetal sampling procedures are invasive with some risk of miscarriage. A non-invasive approach to obtain fetal deoxyribonucleic acid (DNA for diagnosis would eliminate this risk. Aim: To develop and evaluate a non-invasive prenatal diagnostic approach for hemoglobinopathies using cell-free fetal DNA circulating in the maternal plasma. Settings and Design: Couples referred to us for prenatal diagnosis of hemoglobinopathies where the maternal and paternal mutations were different were included in the study. Materials and Methods: Maternal peripheral blood was collected at different periods of gestation before the invasive fetal sampling procedure was done. The blood was centrifuged to isolate the plasma and prepare DNA. A size separation approach was used to isolate fetal DNA. Nested polymerase chain reaction (PCR-based protocols were developed for detection of the presence or absence of the paternal mutation. Results and Conclusions: There were 30 couples where the parental mutations were different. Of these, in 14 cases the paternal mutation was absent and in 16 cases it was present in the fetus. Using cell-free fetal DNA from maternal plasma, the absence of the paternal mutation was accurately determined in 12 of the 14 cases and the presence of the paternal mutation was correctly identified in 12 of the 16 cases. Thus, this non-invasive approach gave comparable results to those obtained by the conventional invasive fetal sampling methods in 24 cases giving an accuracy of 80.0%. Although the nested PCR approach enabled amplification of small quantities of cell-free DNA from maternal plasma at different periods of gestation after size separation to eliminate the more abundant maternal DNA, an accurate diagnosis of the presence or absence of the paternal mutation in the fetus was not possible in all cases to make it clinically

  1. Chediak-Higashi syndrome: description of two novel homozygous missense mutations causing divergent clinical phenotype.

    Science.gov (United States)

    Sánchez-Guiu, Isabel; Antón, Ana I; García-Barberá, Nuria; Navarro-Fernández, José; Martínez, Constantino; Fuster, Jose L; Couselo, Jose M; Ortuño, Francisco J; Vicente, Vicente; Rivera, Jose; Lozano, Maria L

    2014-01-01

    Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disease resulting from mutations in the LYST/CHS1 gene, which encodes for a 429 kDa protein, CHS1/LYST, that regulates vesicle trafficking and determines the size of lysosomes and other organelles. To date, 60 different mutations have been characterized, and a reasonably straightforward phenotype-genotype correlation has been suggested. We describe two patients on opposite ends of the CHS clinical spectrum with novel missense mutations. We characterized these patients in terms of their mutations, protein localization and expression, mRNA stability, and electrostatic potential. Patient 1 is the first report of a severe early-onset CHS with a homozygous missense mutation (c.11362 G>A, p.G3725R) in the LYST/CHS1 gene. This molecular change results in a reduction at the CHS1 protein level, not due to an mRNA effect, but maybe a consequence of both, a change in the structure of the protein and most likely attributable to the remarkable serious perturbation in the electrostatic potential. Patient 2, who exhibited the adolescence form of the disease, was found to be homozygous for a novel missense mutation c.961 T>C, p.C258R, which seemed to have minor effect on the structure of the CHS1/LYST protein. Reexamining accepted premises of missense mutant alleles being reported among patients with clinically mild forms of the disorder should be carried out, and attempts to link genotype and clinical phenotype require identifying the actual molecular effect of the mutation. Early and accurate diagnosis of the severity of the disease is extremely important to early differentiate patients who would benefit from premature enrollment into a transplantation protocol. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. BRCA mutations cause reduction in miR-200c expression in triple negative breast cancer.

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    Erturk, Elif; Cecener, Gulsah; Tezcan, Gulcin; Egeli, Unal; Tunca, Berrin; Gokgoz, Sehsuvar; Tolunay, Sahsine; Tasdelen, Ismet

    2015-02-10

    Triple negative breast cancer (TNBC) is the most aggressive and poorly understood subclass of breast cancer (BC). Over the recent years, miRNA expression studies have been providing certain detailed overview that aberrant expression of miRNAs is associated with TNBC. Although TNBC tumors are strongly connected with loss of function of BRCA genes, there is no knowledge about the effect of BRCA mutation status on miRNA expressions in TNBC cases. The aims of this study were to evaluate the expression profile of miRNAs that plays role in TNBC progression and the role of BRCA mutations in their regulation. The expression level of BC associated 13 miRNAs was analyzed in 7 BRCA mutations positive, 6 BRCA mutations negative TNBC cases and 20 non-tumoral tissues using RT-PCR. According to RT2 Profiler PCR Array Data Analysis, let-7a expression was 4.67 fold reduced in TNBCs as compared to normal tissues (P=0.031). In addition, miR-200c expression was 5.75 fold reduced in BRCA mutation positive TNBC tumors (P=0.005). Analysis revealed a negative correlation between miR-200c and VEGFA expressions (r=-468). Thus, miR-200c may be involved in invasion and metastasis in TNBC cases with BRCA mutation. In this study we provide the knowledge on the first report of association between microRNA-200c and BRCA mutations in TNBC. Further studies and evaluations are required, but this miRNA may provide novel therapeutic molecular targets for TNBC treatment and new directions for the development of anticancer drugs. Copyright © 2014. Published by Elsevier B.V.

  3. Pseudodominant inheritance of goitrous congenital hypothyroidism caused by TPO mutations: molecular and in silico studies.

    Science.gov (United States)

    Deladoëy, Johnny; Pfarr, Nicole; Vuissoz, Jean-Marc; Parma, Jasmine; Vassart, Gilbert; Biesterfeld, Stefan; Pohlenz, Joachim; Van Vliet, Guy

    2008-02-01

    Most cases of goitrous congenital hypothyroidism (CH) from thyroid dyshormonogenesis 1) follow a recessive mode of inheritance and 2) are due to mutations in the thyroid peroxidase gene (TPO). We report the genetic mechanism underlying the apparently dominant inheritance of goitrous CH in a nonconsanguineous family of French Canadian origin. Two brothers identified by newborn TSH screening had severe hypothyroidism and a goiter with increased (99m)Tc uptake. The mother was euthyroid, but the father and two paternal uncles had also been diagnosed with goitrous CH. After having excluded PAX8 gene mutations, we hypothesized that the underlying defect could be TPO mutations. Both compound heterozygous siblings had inherited a mutant TPO allele carried by their mother (c.1496delC; p.Pro499Argfs2X), and from their father, one brother had inherited a missense mutation (c.1978C-->G; p.Gln660Glu) and the other an insertion (c.1955insT; p.Phe653Valfs15X). The thyroid gland of one uncle who is a compound heterozygote for TPO mutations (p.Phe653Valfs15X/p.Gln660Glu) was removed because of concurrent multiple endocrine neoplasia type 2A. Immunohistochemistry revealed normal TPO staining, implying that Gln660Glu TPO is expressed properly. Modeling of this mutant in silico suggests that its three-dimensional structure is conserved, whereas the electrostatic binding energy between the Gln660Glu TPO and its heme group becomes repulsive. We report a pedigree presenting with pseudodominant goitrous CH due to segregation of three different TPO mutations. Although goitrous CH generally follows a recessive mode of inheritance, the high frequency of TPO mutations carriers may lead to pseudodominant inheritance.

  4. Mutations in the lysosomal [beta]-galactosidase gene that cause the adult form of GMI gangliosidosis

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, S.; Rafi, M.A.; Wenger, D.A. (Thomas Jefferson Univ., Philadelphia, PA (United States))

    1994-06-01

    Three adult patients with acid-galactosidase deficiency/GM1 gangliosidosis who were from two unrelated families of Scandinavian descent were found to share a common point mutation in the coding region of the corresponding gene. The patients share common clinical features, including early dysarthria, mild ataxia, and bone abnormalities. When cDNA from the two patients in family 1 was PCR amplified and sequenced, most (39/41) of the clones showed a C-to-T transition (C[yields]T) at nucleotide 245 (counting from the initiation codon). This mutation changes the codon for the Thr(ACG) to Met(ATG). Mutant and normal sequences were also found in that position in genomic DNA, indicating the presence of another mutant allele. Genomic DNA from the patient in family 2 revealed the same point mutation in one allele. It was determined that in each family only the father carried the C[yields]T mutation. Expression studies showed that this mutation produced 3%-4% of [beta]-galactosidase activity, confirming its deleterious effects. The cDNA clones from the patients in family 1 that did not contain the C[yields]T revealed a 20-bp insertion of intronic sequence between nucleotides 75 and 76, the location of the first intron. Further analysis showed the insertion of a T near the 5[prime] splice donor site which led to the use of a cryptic splice site. It appears that the C[yields]T mutation results in enough functional enzyme to produce a mild adult form of the disease, even in the presence of a second mutation that likely produces nonfunctional enzyme. 31 refs., 7 figs., 1 tab.

  5. Naturally occurring rhodopsin mutation in the dog causes retinal dysfunction and degeneration mimicking human dominant retinitis pigmentosa.

    Science.gov (United States)

    Kijas, James W; Cideciyan, Artur V; Aleman, Tomas S; Pianta, Michael J; Pearce-Kelling, Susan E; Miller, Brian J; Jacobson, Samuel G; Aguirre, Gustavo D; Acland, Gregory M

    2002-04-30

    Rhodopsin is the G protein-coupled receptor that is activated by light and initiates the transduction cascade leading to night (rod) vision. Naturally occurring pathogenic rhodopsin (RHO) mutations have been previously identified only in humans and are a common cause of dominantly inherited blindness from retinal degeneration. We identified English Mastiff dogs with a naturally occurring dominant retinal degeneration and determined the cause to be a point mutation in the RHO gene (Thr4Arg). Dogs with this mutant allele manifest a retinal phenotype that closely mimics that in humans with RHO mutations. The phenotypic features shared by dog and man include a dramatically slowed time course of recovery of rod photoreceptor function after light exposure and a distinctive topographic pattern to the retinal degeneration. The canine disease offers opportunities to explore the basis of prolonged photoreceptor recovery after light in RHO mutations and determine whether there are links between the dysfunction and apoptotic retinal cell death. The RHO mutant dog also becomes the large animal needed for preclinical trials of therapies for a major subset of human retinopathies.

  6. Predicting Binding Free Energy Change Caused by Point Mutations with Knowledge-Modified MM/PBSA Method.

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    Marharyta Petukh

    2015-07-01

    Full Text Available A new methodology termed Single Amino Acid Mutation based change in Binding free Energy (SAAMBE was developed to predict the changes of the binding free energy caused by mutations. The method utilizes 3D structures of the corresponding protein-protein complexes and takes advantage of both approaches: sequence- and structure-based methods. The method has two components: a MM/PBSA-based component, and an additional set of statistical terms delivered from statistical investigation of physico-chemical properties of protein complexes. While the approach is rigid body approach and does not explicitly consider plausible conformational changes caused by the binding, the effect of conformational changes, including changes away from binding interface, on electrostatics are mimicked with amino acid specific dielectric constants. This provides significant improvement of SAAMBE predictions as indicated by better match against experimentally determined binding free energy changes over 1300 mutations in 43 proteins. The final benchmarking resulted in a very good agreement with experimental data (correlation coefficient 0.624 while the algorithm being fast enough to allow for large-scale calculations (the average time is less than a minute per mutation.

  7. Point mutation of Arg440 to his in cytochrome P450c17 causes severe 17{alpha}-hydroxylase deficiency

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    Fardella, C.E.; Hum, D.W.; Miller, W.L. [Univ. of California, San Francisco, CA (United States); Homoki, J. [Univ. of Ulm (Germany)

    1994-07-01

    Genetic disorders in the gene encoding P450c17 cause 17{alpha}-hydroxylase deficiency. The consequent defects in the synthesis of cortisol and sex steroids cause sexual infantilism and a female phenotype in both genetic sexes as well as mineralorcorticoid excess and hypertension. A 15-yr-old patient from Germany was seen for absent pubertal development and mild hypertension with hypokalemia, high concentrations of 17-deoxysteroids, and hypergonadotropic hypogonadism. Analysis of her P450c17 gene by polymerase chain reaction amplification and direct sequencing showed mutation of codon 440 from CGC (Arg) to CAC (His). Expression of a vector encoding this mutated form of P450c17 in transfected nonsteroidogenic COS-1 cells showed that the mutant P450c17 protein was produced, but it lacked both 17{alpha}-hydroxylase and 17,20-lyase activities. To date, 15 different P450c17 mutations have been described in 23 patients with 17{alpha}-hydroxylase deficiency, indicating that mutations in this gene are due to random events. 36 refs., 3 figs., 2 tabs.

  8. A nonsense mutation in the acid α-glucosidase gene causes Pompe disease in Finnish and Swedish Lapphunds.

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    Eija H Seppälä

    Full Text Available Pompe disease is a recessively inherited and often fatal disorder caused by the deficiency of acid α-glucosidase, an enzyme encoded by the GAA gene and needed to break down glycogen in lysosomes. This glycogen storage disease type II has been reported also in Swedish Lapphund dogs. Here we describe the genetic defect in canine Pompe disease and show that three related breeds from Scandinavia carry the same mutation. The affected dogs are homozygous for the GAA c.2237G>A mutation leading to a premature stop codon at amino acid position 746. The corresponding mutation has previously been reported in humans and causes infantile Pompe disease in combination with a second fully deleterious mutation. The affected dogs from both the Finnish as well as the Swedish breed mimic infantile-onset Pompe disease genetically, but also clinico-pathologically. Therefore this canine model provides a valuable tool for preclinical studies aimed at the development of gene therapy in Pompe disease.

  9. Novel mutations in genes encoding subcortical maternal complex proteins may cause human embryonic developmental arrest.

    Science.gov (United States)

    Wang, Xueqian; Song, Di; Mykytenko, Dmytro; Kuang, Yanping; Lv, Qifeng; Li, Bin; Chen, Biaobang; Mao, Xiaoyan; Xu, Yao; Zukin, Valery; Mazur, Pavlo; Mu, Jian; Yan, Zheng; Zhou, Zhou; Li, Qiaoli; Liu, Suying; Jin, Li; He, Lin; Sang, Qing; Sun, Zhaogui; Dong, Xi; Wang, Lei

    2018-03-21

    Successful human reproduction initiates from normal gamete formation, fertilization and early embryonic development. Abnormalities in any of these steps will lead to infertility. Many infertile patients undergo several failures of IVF and intracytoplasmic sperm injection (ICSI) cycles, and embryonic developmental arrest is a common phenotype in cases of recurrent failure of IVF/ICSI attempts. However, the genetic basis for this phenotype is poorly understood. The subcortical maternal complex (SCMC) genes play important roles during embryonic development, and using whole-exome sequencing novel biallelic mutations in the SCMC genes TLE6, PADI6 and KHDC3L were identified in four patients with embryonic developmental arrest. A mutation in TLE6 was found in a patient with cleaved embryos that arrested on day 3 and failed to form blastocysts. Two patients with embryos that arrested at the cleavage stage had mutations in PADI6, and a mutation in KHDC3L was found in a patient with embryos arrested at the morula stage. No mutations were identified in these genes in an additional 80 patients. These findings provide further evidence for the important roles of TLE6, PADI6 and KHDC3L in embryonic development. This work lays the foundation for the genetic diagnosis of patients with recurrent IVF/ICSI failure. Copyright © 2018 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  10. Disruption of germination and seedling development in Brassica napus by mutations causing severe seed hormonal imbalance

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    Tung eNguyen

    2016-03-01

    Full Text Available The Brassica napus (oilseed rape accession 1012-98 shows a disturbed germination phenotype that was thought to be associated with its lack of testa pigmentation and thin seed coat. Here we demonstrate that the disturbed germination and seedling development are actually due to independent mutations that disrupt the balance of hormone metabolites and their regulators in the seeds. High-throughput UPLC-MS/MS hormone profiling of seeds and seedlings before and after germination revealed that 1012-98 has a severely disturbed hormone balance with extremely atypical, excessive quantities of auxin and ABA metabolites. The resulting hypersensitivity to abscisic acid (ABA and a corresponding increase in dormancy often results in death of the embryo after imbibition or high frequencies of disturbed, often lethal developmental phenotypes, resembling Arabidopsis mutants for the auxin regulatory factor gene ARF10 or the auxin-overproducing transgenic line iaaM-OX. Molecular cloning of Brassica ARF10 orthologues revealed four loci in normal B. napus, two derived from the Brassica A genome and two from the C genome. On the other hand, the phenotypic mutant 1012-98 exhibited amplification of C-genome BnaC.ARF10 copy number along with a chimeric allele originating from recombination between homoeologous A and C genome loci which lead to minor increase of Bna.ARF10 transcription on the critical timepoint for seed germination, the indirect regulator of ABI3, the germinative inhibitor. Bna.GH3.5 expression was upregulated to conjugate free auxin to IAA-asp between 2-6 DAS. Functional amino acid changes were also found in important DNA binding domains of one BnaC.ARF10 locus, suggesting that regulatory changes in Bna.ARF10 are collectively responsible for the observed phenotpyes in 1012-98. To our knowledge, this study is the first to report disruption of germination and seedling development in Brassica napus caused by the crosstalk of auxin-ABA and the

  11. Disruption of Germination and Seedling Development in Brassica napus by Mutations Causing Severe Seed Hormonal Imbalance.

    Science.gov (United States)

    Nguyen, Tung C T; Obermeier, Christian; Friedt, Wolfgang; Abrams, Suzanne R; Snowdon, Rod J

    2016-01-01

    The Brassica napus (oilseed rape) accession 1012-98 shows a disturbed germination phenotype that was thought to be associated with its lack of testa pigmentation and thin seed coat. Here, we demonstrate that the disturbed germination and seedling development are actually due to independent mutations that disrupt the balance of hormone metabolites and their regulators in the seeds. High-throughput UPLC-MS/MS hormone profiling of seeds and seedlings before and after germination revealed that 1012-98 has a severely disturbed hormone balance with extremely atypical, excessive quantities of auxin and ABA metabolites. The resulting hypersensitivity to abscisic acid (ABA) and a corresponding increase in dormancy often results in death of the embryo after imbibition or high frequencies of disturbed, often lethal developmental phenotypes, resembling Arabidopsis mutants for the auxin regulatory factor gene ARF10 or the auxin-overproducing transgenic line iaaM-OX. Molecular cloning of Brassica ARF10 orthologs revealed four loci in normal B. napus, two derived from the Brassica A genome and two from the C genome. On the other hand, the phenotypic mutant 1012-98 exhibited amplification of C-genome BnaC.ARF10 copy number along with a chimeric allele originating from recombination between homeologous A and C genome loci which lead to minor increase of Bna.ARF10 transcription on the critical timepoint for seed germination, the indirect regulator of ABI3, the germinative inhibitor. Bna.GH3.5 expression was upregulated to conjugate free auxin to IAA-asp between 2 and 6 DAS. Functional amino acid changes were also found in important DNA binding domains of one BnaC.ARF10 locus, suggesting that regulatory changes in Bna.ARF10 are collectively responsible for the observed phenotpyes in 1012-98. To our knowledge, this study is the first to report disruption of germination and seedling development in Brassica napus caused by the crosstalk of auxin-ABA and the corresponding regulators Bna

  12. Interleukin-6 Deficiency Does Not Affect Motor Neuron Disease Caused by Superoxide Dismutase 1 Mutation.

    Science.gov (United States)

    Han, Yongmei; Ripley, Barry; Serada, Satoshi; Naka, Tetsuji; Fujimoto, Minoru

    2016-01-01

    Amyotrophic Lateral Sclerosis (ALS) is an adult-onset, progressive, motor neuron degenerative disease. Recent evidence indicates that inflammation is associated with many neurodegenerative diseases including ALS. Previously, abnormal levels of inflammatory cytokines including IL-1β, IL-6 and TNF-α were described in ALS patients and/or in mouse ALS models. In addition, one study showed that blocking IL-1β could slow down progression of ALS-like symptoms in mice. In this study, we examined a role for IL-6 in ALS, using an animal model for familial ALS. Mice with mutant SOD1 (G93A) transgene, a model for familial ALS, were used in this study. The expression of the major inflammatory cytokines, IL-6, IL-1β and TNF-α, in spinal cords of these SOD1 transgenic (TG) mice were assessed by real time PCR. Mice were then crossed with IL-6(-/-) mice to generate SOD1TG/IL-6(-/-) mice. SOD1 TG/IL-6(-/-) mice (n = 17) were compared with SOD1 TG/IL-6(+/-) mice (n = 18), SOD1 TG/IL-6(+/+) mice (n = 11), WT mice (n = 15), IL-6(+/-) mice (n = 5) and IL-6(-/-) mice (n = 8), with respect to neurological disease severity score, body weight and the survival. We also histologically compared the motor neuron loss in lumber spinal cords and the atrophy of hamstring muscles between these mouse groups. Levels of IL-6, IL-1β and TNF-α in spinal cords of SOD1 TG mice was increased compared to WT mice. However, SOD1 TG/IL-6(-/-) mice exhibited weight loss, deterioration in motor function and shortened lifespan (167.55 ± 11.52 days), similarly to SOD1 TG /IL-6(+/+) mice (164.31±12.16 days). Motor neuron numbers and IL-1β and TNF-α levels in spinal cords were not significantly different in SOD1 TG /IL-6(-/-) mice and SOD1 TG /IL-6 (+/+) mice. These results provide compelling preclinical evidence indicating that IL-6 does not directly contribute to motor neuron disease caused by SOD1 mutations.

  13. Interleukin-6 Deficiency Does Not Affect Motor Neuron Disease Caused by Superoxide Dismutase 1 Mutation.

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    Yongmei Han

    Full Text Available Amyotrophic Lateral Sclerosis (ALS is an adult-onset, progressive, motor neuron degenerative disease. Recent evidence indicates that inflammation is associated with many neurodegenerative diseases including ALS. Previously, abnormal levels of inflammatory cytokines including IL-1β, IL-6 and TNF-α were described in ALS patients and/or in mouse ALS models. In addition, one study showed that blocking IL-1β could slow down progression of ALS-like symptoms in mice. In this study, we examined a role for IL-6 in ALS, using an animal model for familial ALS.Mice with mutant SOD1 (G93A transgene, a model for familial ALS, were used in this study. The expression of the major inflammatory cytokines, IL-6, IL-1β and TNF-α, in spinal cords of these SOD1 transgenic (TG mice were assessed by real time PCR. Mice were then crossed with IL-6(-/- mice to generate SOD1TG/IL-6(-/- mice. SOD1 TG/IL-6(-/- mice (n = 17 were compared with SOD1 TG/IL-6(+/- mice (n = 18, SOD1 TG/IL-6(+/+ mice (n = 11, WT mice (n = 15, IL-6(+/- mice (n = 5 and IL-6(-/- mice (n = 8, with respect to neurological disease severity score, body weight and the survival. We also histologically compared the motor neuron loss in lumber spinal cords and the atrophy of hamstring muscles between these mouse groups.Levels of IL-6, IL-1β and TNF-α in spinal cords of SOD1 TG mice was increased compared to WT mice. However, SOD1 TG/IL-6(-/- mice exhibited weight loss, deterioration in motor function and shortened lifespan (167.55 ± 11.52 days, similarly to SOD1 TG /IL-6(+/+ mice (164.31±12.16 days. Motor neuron numbers and IL-1β and TNF-α levels in spinal cords were not significantly different in SOD1 TG /IL-6(-/- mice and SOD1 TG /IL-6 (+/+ mice.These results provide compelling preclinical evidence indicating that IL-6 does not directly contribute to motor neuron disease caused by SOD1 mutations.

  14. Pathological hemichannels associated with human Cx26 mutations causing Keratitis-Ichthyosis-Deafness syndrome

    Science.gov (United States)

    Levit, Noah A.; Mese, Gulistan; Basaly, Mena-George R.; White, Thomas W.

    2011-01-01

    Connexin (Cx) proteins form intercellular gap junction channels by first assembling into single membrane hemichannels that then dock to connect the cytoplasm of two adjacent cells. Gap junctions are highly specialized structures that allow the direct passage of small molecules between cells to maintain tissue homeostasis. Functional activity of nonjunctional hemichannels has now been shown in several experimental systems. Hemichannels may constitute an important diffusional exchange pathway with the extracellular space, but the extent of their normal physiological role is currently unknown. Aberrant hemichannel activity has been linked to mutations of connexin proteins involved in genetic diseases. Here, we review a proposed role for hemichannels in the pathogenesis of Keratitis-Ichthyosis-Deafness (KID) syndrome associated with connexin26 (Cx26) mutations. Continued functional evaluation of mutated hemichannels linked to human hereditary disorders may provide additional insights into the mechanisms governing their regulation in normal physiology and dysregulation in disease. PMID:21933663

  15. A mutation in canine CLN5 causes neuronal ceroid lipofuscinosis in Border collie dogs.

    Science.gov (United States)

    Melville, Scott A; Wilson, Carmen L; Chiang, Chiu S; Studdert, Virginia P; Lingaas, Frode; Wilton, Alan N

    2005-09-01

    Neuronal ceroid lipofuscinosis (NCL) is a neurodegenerative disease found in Border collie dogs, humans, and other animals. Disease gene studies in humans and animals provided candidates for the NCL gene in Border collies. A combination of linkage analysis and comparative genomics localized the gene to CFA22 in an area syntenic to HSA13q that contains the CLN5 gene responsible for the Finnish variant of human late infantile NCL. Sequencing of CLN5 revealed a nonsense mutation (Q206X) within exon 4 that correlated with NCL in Border collies. This truncation mutation should result in a protein product of a size similar to that of some mutations identified in human CLN5 and therefore the Border collie may make a good model for human NCL. A simple test was developed to enable screening of the Border collie population for carriers so the disease can be eliminated as a problem in the breed.

  16. Mutations in the Gene PRRT2 Cause Paroxysmal Kinesigenic Dyskinesia with Infantile Convulsions

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    Hsien-Yang Lee

    2012-01-01

    Full Text Available Paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC is an episodic movement disorder with autosomal-dominant inheritance and high penetrance, but the causative genetic mutation is unknown. We have now identified four truncating mutations involving the gene PRRT2 in the vast majority (24/25 of well-characterized families with PKD/IC. PRRT2 truncating mutations were also detected in 28 of 78 additional families. PRRT2 encodes a proline-rich transmembrane protein of unknown function that has been reported to interact with the t-SNARE, SNAP25. PRRT2 localizes to axons but not to dendritic processes in primary neuronal culture, and mutants associated with PKD/IC lead to dramatically reduced PRRT2 levels, leading ultimately to neuronal hyperexcitability that manifests in vivo as PKD/IC.

  17. A mutation in the MATP gene causes the cream coat colour in the horse

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    Guérin Gérard

    2003-01-01

    Full Text Available Abstract In horses, basic colours such as bay or chestnut may be partially diluted to buckskin and palomino, or extremely diluted to cream, a nearly white colour with pink skin and blue eyes. This dilution is expected to be controlled by one gene and we used both candidate gene and positional cloning strategies to identify the "cream mutation". A horse panel including reference colours was established and typed for different markers within or in the neighbourhood of two candidate genes. Our data suggest that the causal mutation, a G to A transition, is localised in exon 2 of the MATP gene leading to an aspartic acid to asparagine substitution in the encoded protein. This conserved mutation was also described in mice and humans, but not in medaka.

  18. Confirmation that RIPK4 mutations cause not only Bartsocas-Papas syndrome but also CHAND syndrome.

    Science.gov (United States)

    Busa, Tiffany; Jeraiby, Mohammed; Clémenson, Alix; Manouvrier, Sylvie; Granados, Viviana; Philip, Nicole; Touraine, Renaud

    2017-11-01

    CHAND syndrome is an autosomal recessive disorder characterized by curly hair, ankyloblepharon, and nail dysplasia. Only few patients were reported to date. A homozygous RIPK4 mutation was recently identified by homozygosity mapping and whole exome sequencing in three patients from an expanded consanguineous kindred with a clinical diagnosis of CHAND syndrome. RIPK4 was previously known to be implicated in Bartsocas-Papas syndrome, the autosomal recessive form of popliteal pterygium syndrome. We report here two cases of RIPK4 homozygous mutations in a fetus with severe Bartsocas-Papas syndrome and a patient with CHAND syndrome. The patient with CHAND syndrome harbored the same mutation as the one identified in the family previously reported. We thus confirm the implication of RIPK4 gene in CHAND syndrome in addition to Bartsocas-Papas syndrome and discuss genotype/phenotype correlations. © 2017 Wiley Periodicals, Inc.

  19. Muscarinic Acetylcholine Receptor M3 Mutation Causes Urinary Bladder Disease and a Prune-Belly-like Syndrome.

    Science.gov (United States)

    Weber, Stefanie; Thiele, Holger; Mir, Sevgi; Toliat, Mohammad Reza; Sozeri, Betül; Reutter, Heiko; Draaken, Markus; Ludwig, Michael; Altmüller, Janine; Frommolt, Peter; Stuart, Helen M; Ranjzad, Parisa; Hanley, Neil A; Jennings, Rachel; Newman, William G; Wilcox, Duncan T; Thiel, Uwe; Schlingmann, Karl Peter; Beetz, Rolf; Hoyer, Peter F; Konrad, Martin; Schaefer, Franz; Nürnberg, Peter; Woolf, Adrian S

    2011-11-11

    Urinary bladder malformations associated with bladder outlet obstruction are a frequent cause of progressive renal failure in children. We here describe a muscarinic acetylcholine receptor M3 (CHRM3) (1q41-q44) homozygous frameshift mutation in familial congenital bladder malformation associated with a prune-belly-like syndrome, defining an isolated gene defect underlying this sometimes devastating disease. CHRM3 encodes the M3 muscarinic acetylcholine receptor, which we show is present in developing renal epithelia and bladder muscle. These observations may imply that M3 has a role beyond its known contribution to detrusor contractions. This Mendelian disease caused by a muscarinic acetylcholine receptor mutation strikingly phenocopies Chrm3 null mutant mice. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  20. Non-DNA binding, dominant-negative, human PPARγ mutations cause lipodystrophic insulin resistance

    Science.gov (United States)

    Agostini, Maura; Schoenmakers, Erik; Mitchell, Catherine; Szatmari, Istvan; Savage, David; Smith, Aaron; Rajanayagam, Odelia; Semple, Robert; Luan, Jian'an; Bath, Louise; Zalin, Anthony; Labib, Mourad; Kumar, Sudhesh; Simpson, Helen; Blom, Dirk; Marais, David; Schwabe, John; Barroso, Inês; Trembath, Richard; Wareham, Nicholas; Nagy, Laszlo; Gurnell, Mark; O'Rahilly, Stephen; Chatterjee, Krishna

    2006-01-01

    Summary PPARγ is essential for adipogenesis and metabolic homeostasis. We describe mutations in the DNA and ligand binding domains of human PPARγ in lipodystrophic, severe insulin resistance. These receptor mutants lack DNA binding and transcriptional activity but can translocate to the nucleus, interact with PPARγ coactivators and inhibit coexpressed wild-type receptor. Expression of PPARγ target genes is markedly attenuated in mutation-containing versus receptor haploinsufficent primary cells, indicating that such dominant-negative inhibition operates in vivo. Our observations suggest that these mutants restrict wild-type PPARγ action via a non-DNA binding, transcriptional interference mechanism, which may involve sequestration of functionally limiting coactivators. PMID:17011503

  1. Exome sequencing reveals VCP mutations as a cause of familial ALS

    OpenAIRE

    Johnson, Janel O.; Mandrioli, Jessica; Benatar, Michael; Abramzon, Yevgeniya; Van Deerlin, Vivianna M.; Trojanowski, John Q.; Gibbs, J Raphael; Brunetti, Maura; Gronka, Susan; Wuu, Joanne; Ding, Jinhui; McCluskey, Leo; Martinez-Lage, Maria; Falcone, Dana; Hernandez, Dena G.

    2010-01-01

    Using exome sequencing, we identified a p.R191Q amino acid change in the valosin-containing protein (VCP) gene in an Italian family with autosomal dominantly inherited amyotrophic lateral sclerosis (ALS). Mutations in VCP have previously been identified in families with Inclusion Body Myopathy, Paget’s disease and Frontotemporal Dementia (IBMPFD). Screening of VCP in a cohort of 210 familial ALS cases and 78 autopsy-proven ALS cases identified four additional mutations including a p.R155H mut...

  2. Mutation Altering the miR-184 Seed Region Causes Familial Keratoconus with Cataract

    OpenAIRE

    Hughes, Anne E.; Bradley, Declan T.; Campbell, Malcolm; Lechner, Judith; Dash, Durga P.; Simpson, David A.; Willoughby, Colin E.

    2011-01-01

    MicroRNAs (miRNAs) bind to complementary sequences within the 3′ untranslated region (UTR) of mRNAs from hundreds of target genes, leading either to mRNA degradation or suppression of translation. We found that a mutation in the seed region of miR-184 (MIR184) is responsible for familial severe keratoconus combined with early-onset anterior polar cataract by deep sequencing of a linkage region known to contain the mutation. The mutant form fails to compete with miR-205 (MIR205) for overlappin...

  3. Mutations affecting components of the SWI/SNF complex cause Coffin-Siris syndrome.

    Science.gov (United States)

    Tsurusaki, Yoshinori; Okamoto, Nobuhiko; Ohashi, Hirofumi; Kosho, Tomoki; Imai, Yoko; Hibi-Ko, Yumiko; Kaname, Tadashi; Naritomi, Kenji; Kawame, Hiroshi; Wakui, Keiko; Fukushima, Yoshimitsu; Homma, Tomomi; Kato, Mitsuhiro; Hiraki, Yoko; Yamagata, Takanori; Yano, Shoji; Mizuno, Seiji; Sakazume, Satoru; Ishii, Takuma; Nagai, Toshiro; Shiina, Masaaki; Ogata, Kazuhiro; Ohta, Tohru; Niikawa, Norio; Miyatake, Satoko; Okada, Ippei; Mizuguchi, Takeshi; Doi, Hiroshi; Saitsu, Hirotomo; Miyake, Noriko; Matsumoto, Naomichi

    2012-03-18

    By exome sequencing, we found de novo SMARCB1 mutations in two of five individuals with typical Coffin-Siris syndrome (CSS), a rare autosomal dominant anomaly syndrome. As SMARCB1 encodes a subunit of the SWItch/Sucrose NonFermenting (SWI/SNF) complex, we screened 15 other genes encoding subunits of this complex in 23 individuals with CSS. Twenty affected individuals (87%) each had a germline mutation in one of six SWI/SNF subunit genes, including SMARCB1, SMARCA4, SMARCA2, SMARCE1, ARID1A and ARID1B.

  4. Biallelic Mutations in MITF Cause Coloboma, Osteopetrosis, Microphthalmia, Macrocephaly, Albinism, and Deafness.

    Science.gov (United States)

    George, Aman; Zand, Dina J; Hufnagel, Robert B; Sharma, Ruchi; Sergeev, Yuri V; Legare, Janet M; Rice, Gregory M; Scott Schwoerer, Jessica A; Rius, Mariana; Tetri, Laura; Gamm, David M; Bharti, Kapil; Brooks, Brian P

    2016-12-01

    Human MITF is, by convention, called the "microphthalmia-associated transcription factor" because of previously published seminal mouse genetic studies; however, mutations in MITF have never been associated with microphthalmia in humans. Here, we describe a syndrome that we term COMMAD, characterized by coloboma, osteopetrosis, microphthalmia, macrocephaly, albinism, and deafness. COMMAD is associated with biallelic MITF mutant alleles and hence suggests a role for MITF in regulating processes such as optic-fissure closure and bone development or homeostasis, which go beyond what is usually seen in individuals carrying monoallelic MITF mutations. Copyright © 2016. Published by Elsevier Inc.

  5. De novo loss- or gain-of-function mutations in KCNA2 cause epileptic encephalopathy

    DEFF Research Database (Denmark)

    Syrbe, Steffen; Hedrich, Ulrike B S; Riesch, Erik

    2015-01-01

    disability, delayed speech development and sometimes ataxia. Functional studies of the two mutations associated with this phenotype showed almost complete loss of function with a dominant-negative effect. Two further individuals presented with a different and more severe epileptic encephalopathy phenotype....... They carried mutations inducing a drastic gain-of-function effect leading to permanently open channels. These results establish KCNA2 as a new gene involved in human neurodevelopmental disorders through two different mechanisms, predicting either hyperexcitability or electrical silencing of KV1.2-expressing...

  6. Nationwide experience of catecholaminergic polymorphic ventricular tachycardia caused by RyR2 mutations

    DEFF Research Database (Denmark)

    Broendberg, Anders Krogh; Nielsen, Jens Cosedis; Bjerre, Jesper

    2017-01-01

    probands, 18 symptomatic and 10 asymptomatic relatives with a RyR2 mutation. Twenty (87%) probands and 10 (36%) relatives had severe presenting symptoms (sudden cardiac death (SCD), aborted SCD (ASCD) or syncope).As compared with symptomatic relatives, probands had lower age at onset of symptoms (16 years...... of the 28 ICD treated patients (7%). No patients receiving treatment died during follow-up (57 months (IQR, 32-139)). Multifocal atrial tachycardia was the predominant symptom in five patients. CONCLUSIONS: In a national cohort of RyR2 mutation-positive CPVT patients, SCD, ASCD and syncope were presenting...

  7. A nonclassical IFITM5 mutation located in the coding region causes severe osteogenesis imperfecta with prenatal onset.

    Science.gov (United States)

    Hoyer-Kuhn, Heike; Semler, Oliver; Garbes, Lutz; Zimmermann, Katharina; Becker, Jutta; Wollnik, Bernd; Schoenau, Eckhard; Netzer, Christian

    2014-06-01

    Osteogenesis imperfecta (OI) is a hereditary connective tissue disorder characterized by a wide range of skeletal symptoms. Most patients have dominantly inherited or de novo mutations in COL1A1 or COL1A2. Up to 5% of patients have OI type V, characterized by hyperplastic callus formation after fractures, calcification of the interosseous membrane of the forearm, and a mesh-like lamellation pattern observed in bone histology. Recently, a heterozygous mutation in the 5'-untranslated region (UTR) of IFITM5 (c.-14C > T) was identified as the underlying cause of OI type V, and only this specific mutation was subsequently identified in all patient cohorts with this OI subtype. We now present a case of a heterozygous mutation within the coding region of IFITM5 (c.119C > T; p.S40L). The mutation occurred de novo in the patient and resulted in severe OI with prenatal onset and extreme short stature. At the age of 19 months, the typical clinical hallmarks of OI type V were not present. Our finding has important consequences for the genetic "work-up" of patients suspected to have OI, both in prenatal and in postnatal settings: The entire gene-not only the 5'-UTR harboring the "classical" OI type V mutation-has to be analyzed to exclude a causal role of IFITM5. We propose that this should be part of the initial diagnostic steps for genetic laboratories performing SANGER sequencing in OI patients. © 2014 American Society for Bone and Mineral Research.

  8. Homozygous FOXE3 mutations cause non-syndromic, bilateral, total sclerocornea, aphakia, microphthalmia and optic disc coloboma.

    Science.gov (United States)

    Ali, Manir; Buentello-Volante, Beatriz; McKibbin, Martin; Rocha-Medina, J Alberto; Fernandez-Fuentes, Narcis; Koga-Nakamura, Wilson; Ashiq, Aruna; Khan, Kamron; Booth, Adam P; Williams, Grange; Raashid, Yasmin; Jafri, Hussain; Rice, Aine; Inglehearn, Chris F; Zenteno, Juan Carlos

    2010-06-23

    To investigate the genetic basis of recessively-inherited congenital, non syndromic, bilateral, total sclerocornea in two consanguineous pedigrees, one from the Punjab province of Pakistan and the other from the Tlaxcala province of Mexico. Ophthalmic examinations were conducted on each family member to confirm their diagnosis and magnetic resonance imaging (MRI) or ultrasonography of the eyes was performed on some family members. Genomic DNA was analyzed by homozygosity mapping using the Affymetrix 6.0 SNP array and linkage was confirmed with polymorphic microsatellite markers. Candidate genes were sequenced. A diagnosis of autosomal recessive sclerocornea was established for 7 members of the Pakistani and 8 members of the Mexican pedigrees. In the Pakistani family we established linkage to a region on chromosome 1p that contained Forkhead Box E3 (FOXE3), a strong candidate gene since FOXE3 mutations had previously been associated with various anterior segment abnormalities. Sequencing FOXE3 identified the previously reported nonsense mutation, c.720C>A, p.C240X, in the Pakistani pedigree and a novel missense mutation which disrupts an evolutionarily conserved residue in the forkhead domain, c.292T>C, p.Y98H, in the Mexican pedigree. Individuals with heterozygous mutations had no ocular abnormalities. MRI or ultrasonography confirmed that the patients with sclerocornea were also aphakic, had microphthalmia and some had optic disc coloboma. This is the fourth report detailing homozygous FOXE3 mutations causing anterior segment abnormalities in human patients. Previous papers have emphasized aphakia and microphthalmia as the primary phenotype, but we find that the initial diagnosis - and perhaps the only one possible in a rural setting - is one of non-syndromic, bilateral, total sclerocornea. Dominantly inherited anterior segment defects have also been noted in association with heterozygous FOXE3 mutations. However the absence of any abnormalities in the FOXE3

  9. Effect of BRCA Mutations on Metastatic Relapse and Cause-specific Survival After Radical Treatment for Localised Prostate Cancer.

    Science.gov (United States)

    Castro, Elena; Goh, Chee; Leongamornlert, Daniel; Saunders, Ed; Tymrakiewicz, Malgorzata; Dadaev, Tokhir; Govindasami, Koveela; Guy, Michelle; Ellis, Steve; Frost, Debra; Bancroft, Elizabeth; Cole, Trevor; Tischkowitz, Marc; Kennedy, M John; Eason, Jacqueline; Brewer, Carole; Evans, D Gareth; Davidson, Rosemarie; Eccles, Diana; Porteous, Mary E; Douglas, Fiona; Adlard, Julian; Donaldson, Alan; Antoniou, Antonis C; Kote-Jarai, Zsofia; Easton, Douglas F; Olmos, David; Eeles, Rosalind

    2015-08-01

    Germline BRCA mutations are associated with worse prostate cancer (PCa) outcomes; however, the most appropriate management for mutation carriers has not yet been investigated. To evaluate the response of BRCA carriers to conventional treatments for localised PCa by analysing metastasis-free survival (MFS) and cause-specific survival (CSS) following radical prostatectomy (RP) or external-beam radiation therapy (RT). Tumour features and outcomes of 1302 patients with local/locally advanced PCa (including 67 BRCA mutation carriers) were analysed. RP was undergone by 535 patients (35 BRCA); 767 received RT (32 BRCA). Median follow-up was 64 mo. Median survival and 3-, 5-, and 10-yr survival rates were estimated using the Kaplan-Meier method. Generated survival curves were compared using the log-rank test. Cox regression analyses were used to assess the prognostic value of BRCA mutations. A total of 67 BRCA carriers and 1235 noncarriers were included. At 3, 5, and 10 yr after treatment, 97%, 94%, and 84% of noncarriers and 90%, 72%, and 50% of carriers were free from metastasis (pBRCA mutations as an independent prognostic factor for MFS (hazard ratio [HR]: 2.36; 95% confidence interval [CI], 1.38-4.03; p=0.002) and CSS (HR: 2.17; 95% CI, 1.16-4.07; p=0.016). BRCA carriers had worse outcomes than noncarriers when conventionally treated for local/locally advanced PCa. Prostate cancer patients with germline BRCA mutations had worse outcomes than noncarriers when conventionally treated with surgery or radiation therapy. Copyright © 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.

  10. A start codon CMT1X mutation associated with transient encephalomyelitis causes complete loss of Cx32.

    Science.gov (United States)

    Sargiannidou, Irene; Kim, Gun-Ha; Kyriakoudi, Styliana; Eun, Baik-Lin; Kleopa, Kleopas A

    2015-07-01

    X-linked Charcot-Marie-Tooth disease (CMTX1) results from numerous mutations in the GJB1 gene encoding the gap junction protein connexin32 (Cx32) and is one of the commonest forms of inherited neuropathy. Owing to the expression of Cx32 not only in Schwann cells but also in oligodendrocytes, a subset of CMT1X patients develops central nervous system (CNS) clinical manifestations in addition to peripheral neuropathy. While most GJB1 mutations appear to cause peripheral neuropathy through loss of Cx32 function, the cellular mechanisms underlying the CNS manifestations remain controversial. A novel start codon GJB1 mutation (p.Met1Ile) has been found in a CMT1X patient presenting with recurrent episodes of transient encephalomyelitis without apparent signs of peripheral neuropathy. In order to clarify the functional consequences of this mutation, we examined the cellular expression of two different constructs cloned from genomic DNA including the mutated start codon. None of the cloned constructs resulted in detectable expression of Cx32 by immunocytochemistry or immunoblot, although mRNA was produced at normal levels. Furthermore, co-expression with the other major oligodendrocyte connexin, Cx47, had no negative effect on GJ formation by Cx47. Finally, lysosomal and proteasomal inhibition in cells expressing the start codon mutant constructs failed to recover any detection of Cx32 as a result of impaired protein degradation. Our results indicate that the Cx32 start codon mutation is equivalent to a complete loss of the protein with failure of translation, although transcription is not impaired. Thus, complete loss of Cx32 function is sufficient to produce CNS dysfunction with clinical manifestations.

  11. Characterization of a Chinese KCNQ1 mutation (R259H) that shortens repolarization and causes short QT syndrome 2.

    Science.gov (United States)

    Wu, Zhi-Juan; Huang, Yun; Fu, Yi-Cheng; Zhao, Xiao-Jing; Zhu, Chao; Zhang, Yu; Xu, Bin; Zhu, Qing-Lei; Li, Yang

    2015-07-01

    To evaluate the association between a KCNQ1 mutation, R259H, and short QT syndrome (SQTS) and to explore the electrophysiological mechanisms underlying their association. We performed genetic screening of SQTS genes in 25 probands and their family members (63 patients). We used direct sequencing to screen the exons and intron-exon boundaries of candidate genes that encode ion channels which contribute to the repolarization of the ventricular action potential, including KCNQ1, KCNH2, KCNE1, KCNE2, KCNJ2, CACNA1c, CACNB2b and CACNA2D1. In one of the 25 SQTS probands screened, we discovered a KCNQ1 mutation, R259H. We cloned R259H and transiently expressed it in HEK-293 cells; then, currents were recorded using whole cell patch clamp techniques. R259H-KCNQ1 showed significantly increased current density, which was approximately 3-fold larger than that of wild type (WT) after a depolarizing pulse at 1 s. The steady state voltage dependence of the activation and inactivation did not show significant differences between the WT and R259H mutation (P > 0.05), whereas the time constant of deactivation was markedly prolonged in the mutant compared with the WT in terms of the test potentials, which indicated that the deactivation of R259H was markedly slower than that of the WT. These results suggested that the R259H mutation can effectively increase the slowly activated delayed rectifier potassium current (I Ks) in phase 3 of the cardiac action potential, which may be an infrequent cause of QT interval shortening. R259H is a gain-of-function mutation of the KCNQ1 channel that is responsible for SQTS2. This is the first time that the R259H mutation was detected in Chinese people.

  12. Incidence of the endothelin receptor B mutation that causes lethal white foal syndrome in white-patterned horses.

    Science.gov (United States)

    Santschi, E M; Vrotsos, P D; Purdy, A K; Mickelson, J R

    2001-01-01

    To determine incidence of the Ile118Lys endothelin receptor B (EDNRB) mutation responsible for overo lethal white syndrome (OLWS) and its association with specific types of white patterning. 945 horses of white-patterned bloodlines and 55 solid-colored horses of other breeds. Horses were genotyped by use of allele-specific polymerase chain reaction to determine incidence of the Ile118Lys EDNRB mutation. Genotypes detected were homozygous Ile118, homozygous Lys118, and heterozygous. All foals with OLWS were homozygous for the Ile118Lys EDNRB mutation, and adults that were homozygous were not found. White patterning was strongly associated with EDNRB genotype. Color patterns with highest incidence (> 94%) of heterozygotes were frame overo, highly white calico overo, and frame blend overo. White-patterned bloodlines with lowest incidence of heterozygotes (white calico overo, splashed white overo, nonframe blend overo, and breeding-stock solid. The mutation was not detected in solid-colored horses from breeds without white patterning. In homozygotes, the Ile118Lys EDNRB mutation causes OLWS. In heterozygotes, the mutation is usually responsible for a frame overo phenotype. The frame pattern can be combined with other white patterns, making accurate estimation of EDNRB genotype by visual inspection difficult. Wide range of incidence of heterozygotes in various subtypes of white-patterned horses indicates different genetic control of these color patterns. Determination of EDNRB genotype by use of a DNA-based test is the only way to determine with certainty whether white-patterned horses can produce a foal affected with OLWS.

  13. Sporadic infantile epileptic encephalopathy caused by mutations in PCDH19 resembles Dravet syndrome but mainly affects females.

    Directory of Open Access Journals (Sweden)

    Christel Depienne

    2009-02-01

    Full Text Available Dravet syndrome (DS is a genetically determined epileptic encephalopathy mainly caused by de novo mutations in the SCN1A gene. Since 2003, we have performed molecular analyses in a large series of patients with DS, 27% of whom were negative for mutations or rearrangements in SCN1A. In order to identify new genes responsible for the disorder in the SCN1A-negative patients, 41 probands were screened for micro-rearrangements with Illumina high-density SNP microarrays. A hemizygous deletion on chromosome Xq22.1, encompassing the PCDH19 gene, was found in one male patient. To confirm that PCDH19 is responsible for a Dravet-like syndrome, we sequenced its coding region in 73 additional SCN1A-negative patients. Nine different point mutations (four missense and five truncating mutations were identified in 11 unrelated female patients. In addition, we demonstrated that the fibroblasts of our male patient were mosaic for the PCDH19 deletion. Patients with PCDH19 and SCN1A mutations had very similar clinical features including the association of early febrile and afebrile seizures, seizures occurring in clusters, developmental and language delays, behavioural disturbances, and cognitive regression. There were, however, slight but constant differences in the evolution of the patients, including fewer polymorphic seizures (in particular rare myoclonic jerks and atypical absences in those with PCDH19 mutations. These results suggest that PCDH19 plays a major role in epileptic encephalopathies, with a clinical spectrum overlapping that of DS. This disorder mainly affects females. The identification of an affected mosaic male strongly supports the hypothesis that cellular interference is the pathogenic mechanism.

  14. Body fat distribution in women with familial partial lipodystrophy caused by mutation in the lamin A/C gene

    Directory of Open Access Journals (Sweden)

    Luciana Z Monteiro

    2012-01-01

    Full Text Available Familial partial lipodystrophy (FPLD, Dunnigan variety, is an autosomal dominant disorder caused due to missense mutations in the lamin A/C (LMNA gene encoding nuclear lamina proteins. Patients with FPLD are predisposed to metabolic complications of insulin resistance such as diabetes. We sought to evaluate and compare body fat distribution with dual-emission X-ray absorptiometry in women with and without FPLD and identify densitometric, clinical and metabolic features.

  15. 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 ref