ABCD syndrome is caused by a homozygous mutation in the EDNRB gene.

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Verheij, Joke B G M; Kunze, Jürgen; Osinga, Jan; van Essen, Anthonie J; Hofstra, Robert M W

2002-03-15

ABCD syndrome is an autosomal recessive syndrome characterized by albinism, black lock, cell migration disorder of the neurocytes of the gut (Hirschsprung disease [HSCR]), and deafness. This phenotype clearly overlaps with the features of the Shah-Waardenburg syndrome, comprising sensorineural deafness; hypopigmentation of skin, hair, and irides; and HSCR. Therefore, we screened DNA of the index patient of the ABCD syndrome family for mutations in the endothelin B receptor (EDNRB) gene, a gene known to be involved in Shah-Waardenburg syndrome. A homozygous nonsense mutation in exon 3 (R201X) of the EDNRB gene was found. We therefore suggest that ABCD syndrome is not a separate entity, but an expression of Shah-Waardenburg syndrome.

A novel homozygous AP4B1 mutation in two brothers with AP-4 deficiency syndrome and ocular anomalies.

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Accogli, Andrea; Hamdan, Fadi F; Poulin, Chantal; Nassif, Christina; Rouleau, Guy A; Michaud, Jacques L; Srour, Myriam

2018-04-01

Adaptor protein complex-4 (AP-4) is a heterotetrameric protein complex which plays a key role in vesicle trafficking in neurons. Mutations in genes affecting different subunits of AP-4, including AP4B1, AP4E1, AP4S1, and AP4M1, have been recently associated with an autosomal recessive phenotype, consisting of spastic tetraplegia, and intellectual disability (ID). The overlapping clinical picture among individuals carrying mutations in any of these genes has prompted the terms "AP-4 deficiency syndrome" for this clinically recognizable phenotype. Using whole-exome sequencing, we identified a novel homozygous mutation (c.991C>T, p.Q331*, NM_006594.4) in AP4B1 in two siblings from a consanguineous Pakistani couple, who presented with severe ID, progressive spastic tetraplegia, epilepsy, and microcephaly. Sanger sequencing confirmed the mutation was homozygous in the siblings and heterozygous in the parents. Similar to previously reported individuals with AP4B1 mutations, brain MRI revealed ventriculomegaly and white matter loss. Interestingly, in addition to the typical facial gestalt reported in other AP-4 deficiency cases, the older brother presented with congenital left Horner syndrome, bilateral optic nerve atrophy and cataract, which have not been previously reported in this condition. In summary, we report a novel AP4B1 homozygous mutation in two siblings and review the phenotype of AP-4 deficiency, speculating on a possible role of AP-4 complex in eye development. © 2018 Wiley Periodicals, Inc.

A homozygous mutation in a consanguineous family consolidates the role of ALDH1A3 in autosomal recessive microphthalmia

DEFF Research Database (Denmark)

Roos, L; Fang, M; Dali, C

2013-01-01

to the identification of new genes. Very recently, homozygous variations within ALDH1A3 have been associated with autosomal recessive microphthalmia with or without cysts or coloboma, and with variable subphenotypes of developmental delay/autism spectrum disorder in eight families. In a consanguineous family where...... three of the five siblings were affected with microphthalmia/coloboma, we identified a novel homozygous missense mutation in ALDH1A3 using exome sequencing. Of the three affected siblings, one had intellectual disability and one had intellectual disability and autism, while the last one presented...... with normal development. This study contributes further to the description of the clinical spectrum associated with ALDH1A3 mutations, and illustrates the interfamilial clinical variation observed in individuals with ALDH1A3 mutations....

Homozygous LIPE mutation in siblings with multiple symmetric lipomatosis, partial lipodystrophy, and myopathy.

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Zolotov, Sagit; Xing, Chao; Mahamid, Riad; Shalata, Adel; Sheikh-Ahmad, Mohammed; Garg, Abhimanyu

2017-01-01

Despite considerable progress in identifying causal genes for lipodystrophy syndromes, the molecular basis of some peculiar adipose tissue disorders remains obscure. In an Israeli-Arab pedigree with a novel autosomal recessive, multiple symmetric lipomatosis (MSL), partial lipodystrophy and myopathy, we conducted exome sequencing of two affected siblings to identify the disease-causing mutation. The 41-year-old female proband and her 36-year-old brother reported marked accumulation of subcutaneous fat in the face, neck, axillae, and trunk but loss of subcutaneous fat from the lower extremities and progressive distal symmetric myopathy during adulthood. They had increased serum creatine kinase levels, hypertriglyceridemia and low levels of high-density lipoprotein cholesterol. Exome sequencing identified a novel homozygous NC_000019.9:g.42906092C>A variant on chromosome 19, leading to a NM_005357.3:c.3103G>T nucleotide change in coding DNA and corresponding p.(Glu1035*) protein change in hormone sensitive lipase (LIPE) gene as the disease-causing variant. Sanger sequencing further confirmed the segregation of the mutation in the family. Hormone sensitive lipase is the predominant regulator of lipolysis from adipocytes, releasing free fatty acids from stored triglycerides. The homozygous null LIPE mutation could result in marked inhibition of lipolysis from some adipose tissue depots and thus may induce an extremely rare phenotype of MSL and partial lipodystrophy in adulthood associated with complications of insulin resistance, such as diabetes, hypertriglyceridemia and hepatic steatosis. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Homozygous and compound heterozygous mutations in the FBN1 gene: unexpected findings in molecular diagnosis of Marfan syndrome.

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Arnaud, Pauline; Hanna, Nadine; Aubart, Mélodie; Leheup, Bruno; Dupuis-Girod, Sophie; Naudion, Sophie; Lacombe, Didier; Milleron, Olivier; Odent, Sylvie; Faivre, Laurence; Bal, Laurence; Edouard, Thomas; Collod-Beroud, Gwenaëlle; Langeois, Maud; Spentchian, Myrtille; Gouya, Laurent; Jondeau, Guillaume; Boileau, Catherine

2017-02-01

Marfan syndrome (MFS) is an autosomal-dominant connective tissue disorder usually associated with heterozygous mutations in the gene encoding fibrillin-1 (FBN1). Homozygous and compound heterozygous cases are rare events and have been associated with a clinical severe presentation. Report unexpected findings of homozygosity and compound heterozygosity in the course of molecular diagnosis of heterozygous MFS and compare the findings with published cases. In the context of molecular diagnosis of heterozygous MFS, systematic sequencing of the FBN1 gene was performed in 2500 probands referred nationwide. 1400 probands carried a heterozygous mutation in this gene. Unexpectedly, among them four homozygous cases (0.29%) and five compound heterozygous cases (0.36%) were identified (total: 0.64%). Interestingly, none of these cases carried two premature termination codon mutations in the FBN1 gene. Clinical features for these carriers and their families were gathered and compared. There was a large spectrum of severity of the disease in probands carrying two mutated FBN1 alleles, but none of them presented extremely severe manifestations of MFS in any system compared with carriers of only one mutated FBN1 allele. This observation is not in line with the severe clinical features reported in the literature for four homozygous and three compound heterozygous probands. Homozygotes and compound heterozygotes were unexpectedly identified in the course of molecular diagnosis of MFS. Contrary to previous reports, the presence of two mutated alleles was not associated with severe forms of MFS. Although homozygosity and compound heterozygosity are rarely found in molecular diagnosis, they should not be overlooked, especially among consanguineous families. However, no predictive evaluation of severity should be provided. 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/.

Mutations of the catalytic subunit of RAB3GAP cause Warburg Micro syndrome

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Aligianis, Irene A; Johnson, Colin A; Gissen, Paul

2005-01-01

Warburg Micro syndrome (WARBM1) is a severe autosomal recessive disorder characterized by developmental abnormalities of the eye and central nervous system and by microgenitalia. We identified homozygous inactivating mutations in RAB3GAP, encoding RAB3 GTPase activating protein, a key regulator...

A homozygous CARD9 mutation in a family with susceptibility to fungal infections.

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Glocker, Erik-Oliver; Hennigs, Andre; Nabavi, Mohammad; Schäffer, Alejandro A; Woellner, Cristina; Salzer, Ulrich; Pfeifer, Dietmar; Veelken, Hendrik; Warnatz, Klaus; Tahami, Fariba; Jamal, Sarah; Manguiat, Annabelle; Rezaei, Nima; Amirzargar, Ali Akbar; Plebani, Alessandro; Hannesschläger, Nicole; Gross, Olaf; Ruland, Jürgen; Grimbacher, Bodo

2009-10-29

Chronic mucocutaneous candidiasis may be manifested as a primary immunodeficiency characterized by persistent or recurrent infections of the mucosa or the skin with candida species. Most cases are sporadic, but both autosomal dominant inheritance and autosomal recessive inheritance have been described. We performed genetic studies in 36 members of a large, consanguineous five-generation family, in which 4 members had recurrent fungal infections and an additional 3 members died during adolescence, 2 after invasive infection of the brain with candida species. All 36 family members were enrolled in the study, and 22 had blood samples taken for DNA analysis. Homozygosity mapping was used to locate the mutated gene. In the 4 affected family members (patients) and the 18 unaffected members we sequenced CARD9, the gene encoding the caspase recruitment domain-containing protein 9, carried out T-cell phenotyping, and performed functional studies, with the use of either leukocytes from the patients or a reconstituted murine model of the genetic defect. We found linkage (lod score, 3.6) to a genomic interval on chromosome 9q, including CARD9. All four patients had a homozygous point mutation in CARD9, resulting in a premature termination codon (Q295X). Healthy family members had wild-type expression of the CARD9 protein; the four patients lacked wild-type expression, which was associated with low numbers of Th17 cells (helper T cells producing interleukin-17). Functional studies based on genetic reconstitution of myeloid cells from Card9(-/-) mice showed that the Q295X mutation impairs innate signaling from the antifungal pattern-recognition receptor dectin-1. An autosomal recessive form of susceptibility to chronic mucocutaneous candidiasis is associated with homozygous mutations in CARD9. 2009 Massachusetts Medical Society

Effects of track structure and cell inactivation on the calculation of heavy ion mutation rates in mammalian cells

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Cucinotta, F. A.; Wilson, J. W.; Shavers, M. R.; Katz, R.

1996-01-01

It has long been suggested that inactivation severely effects the probability of mutation by heavy ions in mammalian cells. Heavy ions have observed cross sections of inactivation that approach and sometimes exceed the geometric size of the cell nucleus in mammalian cells. In the track structure model of Katz the inactivation cross section is found by summing an inactivation probability over all impact parameters from the ion to the sensitive sites within the cell nucleus. The inactivation probability is evaluated using the dose-response of the system to gamma-rays and the radial dose of the ions and may be equal to unity at small impact parameters for some ions. We show how the effects of inactivation may be taken into account in the evaluation of the mutation cross sections from heavy ions in the track structure model through correlation of sites for gene mutation and cell inactivation. The model is fit to available data for HPRT mutations in Chinese hamster cells and good agreement is found. The resulting calculations qualitatively show that mutation cross sections for heavy ions display minima at velocities where inactivation cross sections display maxima. Also, calculations show the high probability of mutation by relativistic heavy ions due to the radial extension of ions track from delta-rays in agreement with the microlesion concept. The effects of inactivation on mutations rates make it very unlikely that a single parameter such as LET or Z*2/beta(2) can be used to specify radiation quality for heavy ion bombardment.

GNE Myopathy in Turkish Sisters with a Novel Homozygous Mutation

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Diniz, Gulden; Secil, Yaprak; Ceylaner, Serdar; Tokucoglu, Figen; Türe, Sabiha; Celebisoy, Mehmet; İncesu, Tülay Kurt; Akhan, Galip

2016-01-01

Background. Hereditary inclusion body myopathy is caused by biallelic defects in the GNE gene located on chromosome 9p13. It generally affects adults older than 20 years of age. Methods and Results. In this study, we present two Turkish sisters with progressive myopathy and describe a novel mutation in the GNE gene. Both sisters had slightly higher levels of creatine kinase (CK) and muscle weakness. The older sister presented at 38 years of age with an inability to climb steps, weakness, and a steppage gait. Her younger sister was 36 years old and had similar symptoms. The first symptoms of the disorder were seen when the sisters were 30 and 34 years old, respectively. The muscle biopsy showed primary myopathic features and presence of rimmed vacuoles. DNA analysis demonstrated the presence of previously unknown homozygous mutations [c.2152 G>A (p.A718T)] in the GNE genes. Conclusion. Based on our literature survey, we believe that ours is the first confirmed case of primary GNE myopathy with a novel missense mutation in Turkey. These patients illustrate that the muscle biopsy is still an important method for the differential diagnosis of vacuolar myopathies in that the detection of inclusions is required for the definitive diagnosis. PMID:27298745

Homozygous EDNRB mutation in a patient with Waardenburg syndrome type 1.

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Morimoto, Noriko; Mutai, Hideki; Namba, Kazunori; Kaneko, Hiroki; Kosaki, Rika; Matsunaga, Tatsuo

2018-04-01

To examine and expand the genetic spectrum of Waardenburg syndrome type 1 (WS1). Clinical features related to Waardenburg syndrome (WS) were examined in a five-year old patient. Mutation analysis of genes related to WS was performed in the proband and her parents. Molecular modeling of EDNRB and the p.R319W mutant was conducted to predict the pathogenicity of the mutation. The proband showed sensorineural hearing loss, heterochromia iridis, and dystopia canthorum, fulfilling the clinical criteria of WS1. Genetic analyses revealed that the proband had no mutation in PAX3 which has been known as the cause of WS1, but had a homozygous missense mutation (p.R319W) in endothelin receptor type B (EDNRB) gene. The asymptomatic parents had the mutation in a heterozygote state. This mutation has been previously reported in a heterozygous state in a patient with Hirschsprung's disease unaccompanied by WS, but the patient and her parents did not show any symptoms in gastrointestinal tract. Molecular modeling of EDNRB with the p.R319W mutation demonstrated reduction of the positively charged surface area in this region, which might reduce binding ability of EDNRB to G protein and lead to abnormal signal transduction underlying the WS phenotype. Our findings suggested that autosomal recessive mutation in EDNRB may underlie a part of WS1 with the current diagnostic criteria, and supported that Hirschsprung's disease is a multifactorial genetic disease which requires additional factors. Further molecular analysis is necessary to elucidate the gene interaction and to reappraise the current WS classification. Copyright © 2017 Elsevier B.V. All rights reserved.

A homozygous nonsense CEP250 mutation combined with a heterozygous nonsense C2orf71 mutation is associated with atypical Usher syndrome.

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Khateb, Samer; Zelinger, Lina; Mizrahi-Meissonnier, Liliana; Ayuso, Carmen; Koenekoop, Robert K; Laxer, Uri; Gross, Menachem; Banin, Eyal; Sharon, Dror

2014-07-01

Usher syndrome (USH) is a heterogeneous group of inherited retinitis pigmentosa (RP) and sensorineural hearing loss (SNHL) caused by mutations in at least 12 genes. Our aim is to identify additional USH-related genes. Clinical examination included visual acuity test, funduscopy and electroretinography. Genetic analysis included homozygosity mapping and whole exome sequencing (WES). A combination of homozygosity mapping and WES in a large consanguineous family of Iranian Jewish origin revealed nonsense mutations in two ciliary genes: c.3289C>T (p.Q1097*) in C2orf71 and c.3463C>T (p.R1155*) in centrosome-associated protein CEP250 (C-Nap1). The latter has not been associated with any inherited disease and the c.3463C>T mutation was absent in control chromosomes. Patients who were double homozygotes had SNHL accompanied by early-onset and severe RP, while patients who were homozygous for the CEP250 mutation and carried a single mutant C2orf71 allele had SNHL with mild retinal degeneration. No ciliary structural abnormalities in the respiratory system were evident by electron microscopy analysis. CEP250 expression analysis of the mutant allele revealed the generation of a truncated protein lacking the NEK2-phosphorylation region. A homozygous nonsense CEP250 mutation, in combination with a heterozygous C2orf71 nonsense mutation, causes an atypical form of USH, characterised by early-onset SNHL and a relatively mild RP. The severe retinal involvement in the double homozygotes indicates an additive effect caused by nonsense mutations in genes encoding ciliary proteins. 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.

Costs of insensitive acetylcholinesterase insecticide resistance for the malaria vector Anopheles gambiae homozygous for the G119S mutation

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Noel Valérie

2010-01-01

Full Text Available Abstract Background The G119S mutation responsible for insensitive acetylcholinesterase resistance to organophosphate and carbamate insecticides has recently been reported from natural populations of Anopheles gambiae in West Africa. These reports suggest there are costs of resistance associated with this mutation for An. gambiae, especially for homozygous individuals, and these costs could be influential in determining the frequency of carbamate resistance in these populations. Methods Life-history traits of the AcerKis and Kisumu strains of An. gambiae were compared following the manipulation of larval food availability in three separate experiments conducted in an insecticide-free laboratory environment. These two strains share the same genetic background, but differ in being homozygous for the presence or absence of the G119S mutation at the ace-1 locus, respectively. Results Pupae of the resistant strain were significantly more likely to die during pupation than those of the susceptible strain. Ages at pupation were significantly earlier for the resistant strain and their dry starved weights were significantly lighter; this difference in weight remained when the two strains were matched for ages at pupation. Conclusions The main cost of resistance found for An. gambiae mosquitoes homozygous for the G119S mutation was that they were significantly more likely to die during pupation than their susceptible counterparts, and they did so across a range of larval food conditions. Comparing the frequency of G119S in fourth instar larvae and adults emerging from the same populations would provide a way to test whether this cost of resistance is being expressed in natural populations of An. gambiae and influencing the dynamics of this resistance mutation.

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

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Ravindran, Ethiraj; Hu, Hao; Yuzwa, Scott A; Hernandez-Miranda, Luis R; Kraemer, Nadine; Ninnemann, Olaf; Musante, Luciana; Boltshauser, Eugen; Schindler, Detlev; Hübner, Angela; Reinecker, Hans-Christian; Ropers, Hans-Hilger; Birchmeier, Carmen; Miller, Freda D; Wienker, Thomas F; Hübner, Christoph; Kaindl, Angela M

2017-04-01

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.

Homozygous ARHGEF2 mutation causes intellectual disability and midbrain-hindbrain malformation

Science.gov (United States)

Yuzwa, Scott A.; Hernandez-Miranda, Luis R.; Musante, Luciana; Boltshauser, Eugen; Schindler, Detlev; Hübner, Angela; Reinecker, Hans-Christian; Ropers, Hans-Hilger; Miller, Freda D.; Hübner, Christoph; Kaindl, Angela M.

2017-01-01

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. PMID:28453519

Identification of a Novel Homozygous Nonsense Mutation Confirms the Implication of GNAT1 in Rod-Cone Dystrophy.

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Cécile Méjécase

Full Text Available GNAT1, encoding the transducin subunit Gα, is an important element of the phototransduction cascade. Mutations in this gene have been associated with autosomal dominant and autosomal recessive congenital stationary night blindness. Recently, a homozygous truncating GNAT1 mutation was identified in a patient with late-onset rod-cone dystrophy. After exclusion of mutations in genes underlying progressive inherited retinal disorders, by targeted next generation sequencing, a 32 year-old male sporadic case with severe rod-cone dystrophy and his unaffected parents were investigated by whole exome sequencing. This led to the identification of a homozygous nonsense variant, c.963C>A p.(Cys321* in GNAT1, which was confirmed by Sanger sequencing. The mother was heterozygous for this variant whereas the variant was absent in the father. c.963C>A p.(Cys321* is predicted to produce a shorter protein that lacks critical sites for the phototransduction cascade. Our work confirms that the phenotype and the mode of inheritance associated with GNAT1 variants can vary from autosomal dominant, autosomal recessive congenital stationary night blindness to autosomal recessive rod-cone dystrophy.

Novel homozygous FANCL mutation and somatic heterozygous SETBP1 mutation in a Chinese girl with Fanconi Anemia.

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Wu, Weiqing; Liu, Yang; Zhou, Qinghua; Wang, Qin; Luo, Fuwei; Xu, Zhiyong; Geng, Qian; Li, Peining; Zhang, Hui Z; Xie, Jiansheng

2017-07-01

Fanconi Anemia (FA) is a rare genetically heterogeneous disorder with 17 known complement groups caused by mutations in different genes. FA complementation group L (FA-L, OMIM #608111) occurred in 0.2% of all FA and only eight mutant variants in the FANCL gene were documented. Phenotype and genotype correlation in FANCL associated FA is still obscure. Here we describe a Chinese girl with FA-L caused by a novel homozygous mutation c.822_823insCTTTCAGG (p.Asp275LeufsX13) in the FANCL gene. The patient's clinical course was typical for FA with progression to bone marrow failure, and death from acute myelomonocytic leukemia (AML-M4) at 9 years of age. Mutation analysis also detected a likely somatic c.2608G > A (p.Gly870Ser) in the SETBP1 gene. Consistent copy number losses of 7q and 18p and gains of 3q and 21q and accumulated non-clonal single cell chromosomal abnormalities were detected in blood leukocytes as her FA progressed. This is the first Chinese FA-L case caused by a novel FANCL mutation. The somatic gene mutation and copy number aberrations could be used to monitor disease progression and the clinical findings provide further information for genotype-phenotype correlation for FA-L. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Report of Chinese family with severe dermatitis, multiple allergies and metabolic wasting syndrome caused by novel homozygous desmoglein-1 gene mutation.

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Cheng, Ruhong; Yan, Ming; Ni, Cheng; Zhang, Jia; Li, Ming; Yao, Zhirong

2016-10-01

Recently, homozygous mutations in the desmoglein-1 (DSG1) gene and heterozygous mutation in the desmoplakin (DSP) gene have been demonstrated to be associated with severe dermatitis, multiple allergies and metabolic wasting (SAM) syndrome (Mendelian Inheritance in Man no. 615508). We aim to identify the molecular basis for a Chinese pedigree of SAM syndrome. A Chinese pedigree of SAM syndrome was subjected to mutation detection in the DSG1 gene. Sequence analysis of the DSG1 gene and quantitative reverse transcriptase polymerase chain reaction analysis for gene expression of DSG1 using cDNA derived from the epidermis of patients and controls were both performed. Skin biopsies were also taken from patients for pathological study and transmission electron microscopy observation. Novel homozygous splicing mutation c.1892-1delG in the exon-intron border of the DSG1 gene has been demonstrated to be associated with SAM syndrome. We report a new family of SAM syndrome of Asian decent and expand the spectrum of mutations in the DSG1 gene. © 2016 Japanese Dermatological Association.

Lethal/severe osteogenesis imperfecta in a large family: a novel homozygous LEPRE1 mutation and bone histological findings

NARCIS (Netherlands)

van Dijk, Fleur S.; Nikkels, Peter G. J.; den Hollander, Nicolette S.; Nesbitt, Isabel M.; van Rijn, Rick R.; Cobben, Jan M.; Pals, Gerard

2011-01-01

We report a large consanguineous Turkish family in which multiple individuals are affected with autosomal recessive lethal or severe osteogenesis imperfecta (OI) due to a novel homozygous LEPRE1 mutation. In one affected individual histological studies of bone tissue were performed, which may

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.

Identification of a novel homozygous mutation, TMPRSS3: c.535G>A, in a Tibetan family with autosomal recessive non-syndromic hearing loss.

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Dongyan Fan

Full Text Available Different ethnic groups have distinct mutation spectrums associated with inheritable deafness. In order to identify the mutations responsible for congenital hearing loss in the Tibetan population, mutation screening for 98 deafness-related genes by microarray and massively parallel sequencing of captured target exons was conducted in one Tibetan family with familiar hearing loss. A homozygous mutation, TMPRSS3: c.535G>A, was identified in two affected brothers. Both parents are heterozygotes and an unaffected sister carries wild type alleles. The same mutation was not detected in 101 control Tibetan individuals. This missense mutation results in an amino acid change (p.Ala179Thr at a highly conserved site in the scavenger receptor cysteine rich (SRCR domain of the TMPRSS3 protein, which is essential for protein-protein interactions. Thus, this mutation likely affects the interactions of this transmembrane protein with extracellular molecules. According to our bioinformatic analyses, the TMPRSS3: c.535G>A mutation might damage protein function and lead to hearing loss. These data suggest that the homozygous mutation TMPRSS3: c.535G>A causes prelingual hearing loss in this Tibetan family. This is the first TMPRSS3 mutation found in the Chinese Tibetan population.

Identification of a novel homozygous mutation in MYO3A in a Chinese family with DFNB30 non-syndromic hearing impairment.

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Qu, Ronggui; Sang, Qing; Xu, Yao; Feng, Ruizhi; Jin, Li; He, Lin; Wang, Lei

2016-05-01

Hearing loss is a common sensory impairment. Several genetic loci or genes responsible for non-syndrome hearing loss have been identified, including the well-known deafness genes GJB2, MT-RNR1 and SLC26A4. MYO3A belongs to the myosin superfamily. Previously only three mutations in this gene have been found in an Isreali family with DFNB30, in which patients demonstrated progressive hearing loss. In this study, we characterized a consanguineous Kazakh family with congenital hearing loss. By targeted sequence capture and next-generation sequencing, we identified a homozygous mutation and did bioinformatics analysis to this mutation. A homozygous mutation, MYO3A:c.1841C>T (p.S614F), was identified to be responsible for the disease. Ser614 is located in the motor domain of MYO3A that is highly conserved among different species. Molecular modeling predicts that the conserved Ser614 may play an important role in maintaining the stability of β-sheet and the interaction between neighboring β-strand. This is the second report on MYO3A mutations in deafness and the first report in China. The finding help facilitate establishing a better relationship between MYO3A mutation and hearing phenotypes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Early presentation of cystic kidneys in a family with a homozygous INVS mutation.

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Oud, Machteld M; van Bon, Bregje W; Bongers, Ernie M H F; Hoischen, Alexander; Marcelis, Carlo L; de Leeuw, Nicole; Mol, Suzanne J J; Mortier, Geert; Knoers, Nine V A M; Brunner, Han G; Roepman, Ronald; Arts, Heleen H

2014-07-01

Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease that is the most frequent monogenic cause of end-stage renal disease in children. Infantile NPHP, often in combination with other features like situs inversus, are commonly caused by mutations in the INVS gene. INVS encodes the ciliary protein inversin, and mutations induce dysfunction of the primary cilia. In this article, we present a family with two severely affected fetuses that were aborted after discovery of grossly enlarged cystic kidneys by ultrasonography before 22 weeks gestation. Exome sequencing showed that the fetuses were homozygous for a previously unreported nonsense mutation, resulting in a truncation in the IQ1 domain of inversin. This mutation induces nonsense-mediated RNA decay, as suggested by a reduced RNA level in fibroblasts derived from the fetus. However, a significant amount of mutant INVS RNA was present in these fibroblasts, yielding mutant inversin protein that was mislocalized. In control fibroblasts, inversin was present in the ciliary axoneme as well as at the basal body, whereas in the fibroblasts from the fetus, inversin could only be detected at the basal body. The phenotype of both fetuses is partly characteristic of infantile NPHP and Potter sequence. We also identified that the fetuses had mild skeletal abnormalities, including shortening and bowing of long bones, which may expand the phenotypic spectrum associated with INVS mutations. © 2014 Wiley Periodicals, Inc.

A New Mouse Model of Limb-Girdle Muscular Dystrophy Type 2I Homozygous for the Common L276I Mutation Mimicking the Mild Phenotype in Humans

DEFF Research Database (Denmark)

Krag, Thomas O; Vissing, John

2015-01-01

Limb-girdle muscular dystrophy type 2I (LGMD2I) is caused by mutations in the Fukutin-related protein (FKRP) gene, leading to inadequate glycosylation of α-dystroglycan, an important protein linking the extracellular matrix to the cytoskeleton. We created a mouse model of the common FKRP L276I...... mutation and a hemizygous FKRP L276I knockout model. We studied histopathology and protein expression in the models at different ages and found that homozygous FKRP L276I mice developed a mild progressive myopathy with increased muscle regeneration and fibrosis starting from 1 year of age. This was likely...... in maintaining proper glycosylation of α-dystroglycan. The mild progression in the homozygous FKRP L276I model resembles that in patients with LGMD2I who are homozygous for the L276I mutation. This animal model could, therefore, be relevant for understanding the pathophysiology of and developing a treatment...

CRISPR Correction of a Homozygous Low-Density Lipoprotein Receptor Mutation in Familial Hypercholesterolemia Induced Pluripotent Stem Cells.

Science.gov (United States)

Omer, Linda; Hudson, Elizabeth A; Zheng, Shirong; Hoying, James B; Shan, Yuan; Boyd, Nolan L

2017-11-01

Familial hypercholesterolemia (FH) is a hereditary disease primarily due to mutations in the low-density lipoprotein receptor (LDLR) that lead to elevated cholesterol and premature development of cardiovascular disease. Homozygous FH patients (HoFH) with two dysfunctional LDLR alleles are not as successfully treated with standard hypercholesterol therapies, and more aggressive therapeutic approaches to control cholesterol levels must be considered. Liver transplant can resolve HoFH, and hepatocyte transplantation has shown promising results in animals and humans. However, demand for donated livers and high-quality hepatocytes overwhelm the supply. Human pluripotent stem cells can differentiate to hepatocyte-like cells (HLCs) with the potential for experimental and clinical use. To be of future clinical use as autologous cells, LDLR genetic mutations in derived FH-HLCs need to be corrected. Genome editing technology clustered-regularly-interspaced-short-palindromic-repeats/CRISPR-associated 9 (CRISPR/Cas9) can repair pathologic genetic mutations in human induced pluripotent stem cells. We used CRISPR/Cas9 genome editing to permanently correct a 3-base pair homozygous deletion in LDLR exon 4 of patient-derived HoFH induced pluripotent stem cells. The genetic correction restored LDLR-mediated endocytosis in FH-HLCs and demonstrates the proof-of-principle that CRISPR-mediated genetic modification can be successfully used to normalize HoFH cholesterol metabolism deficiency at the cellular level.

A novel NaV1.5 voltage sensor mutation associated with severe atrial and ventricular arrhythmias.

Science.gov (United States)

Wang, Hong-Gang; Zhu, Wandi; Kanter, Ronald J; Silva, Jonathan R; Honeywell, Christina; Gow, Robert M; Pitt, Geoffrey S

2016-03-01

Inherited autosomal dominant mutations in cardiac sodium channels (NaV1.5) cause various arrhythmias, such as long QT syndrome and Brugada syndrome. Although dozens of mutations throughout the protein have been reported, there are few reported mutations within a voltage sensor S4 transmembrane segment and few that are homozygous. Here we report analysis of a novel lidocaine-sensitive recessive mutation, p.R1309H, in the NaV1.5 DIII/S4 voltage sensor in a patient with a complex arrhythmia syndrome. We expressed the wild type or mutant NaV1.5 heterologously for analysis with the patch-clamp and voltage clamp fluorometry (VCF) techniques. p.R1309H depolarized the voltage-dependence of activation, hyperpolarized the voltage-dependence of inactivation, and slowed recovery from inactivation, thereby reducing the channel availability at physiologic membrane potentials. Additionally, p.R1309H increased the "late" Na(+) current. The location of the mutation in DIIIS4 prompted testing for a gating pore current. We observed an inward current at hyperpolarizing voltages that likely exacerbates the loss-of-function defects at resting membrane potentials. Lidocaine reduced the gating pore current. The p.R1309H homozygous NaV1.5 mutation conferred both gain-of-function and loss-of-function effects on NaV1.5 channel activity. Reduction of a mutation-induced gating pore current by lidocaine suggested a therapeutic mechanism. Copyright © 2016 Elsevier Ltd. All rights reserved.

Association of a homozygous nonsense mutation in the ABCA4 (ABCR) gene with cone-rod dystrophy phenotype in an Italian family.

Science.gov (United States)

Simonelli, Francesca; Testa, Francesco; Zernant, Jana; Nesti, Anna; Rossi, Settimio; Rinaldi, Ernesto; Allikmets, Rando

2004-01-01

Genetic variation in the ABCA4 (ABCR) gene has been associated with several distinct retinal phenotypes, including Stargardt disease/fundus flavimaculatus (STGD/FFM), cone-rod dystrophy (CRD), retinitis pigmentosa (RP) and age-related macular degeneration. The current model of genotype/phenotype association suggests that patients harboring deleterious mutations in both ABCR alleles would develop RP-like retinal pathology. Here we describe ABCA4-associated phenotypes, including a proband with a homozygous nonsense mutation in a family from Southern Italy. The proband had been originally diagnosed with STGD. Ophthalmologic examination included kinetic perimetry, electrophysiological studies and fluorescein angiography. DNA of the affected individual and family members was analyzed for variants in all 50 exons of the ABCA4 gene by screening on the ABCR400 microarray. A homozygous nonsense mutation 2971G>T (G991X) was detected in a patient initially diagnosed with STGD based on funduscopic evidence, including bull's eye depigmentation of the fovea and flecks at the posterior pole extending to the mid-peripheral retina. Since this novel nucleotide substitution results in a truncated, nonfunctional, ABCA4 protein, the patient was examined in-depth for the severity of the disease phenotype. Indeed, subsequent electrophysiological studies determined severely reduced cone amplitude as compared to the rod amplitude, suggesting the diagnosis of CRD. ABCR400 microarray is an efficient tool for determining causal genetic variation, including new mutations. A homozygous protein-truncating mutation in ABCA4 can cause a phenotype ranging from STGD to CRD as diagnosed at an early stage of the disease. Only a combination of comprehensive genotype/phenotype correlation studies will determine the proper diagnosis and prognosis of ABCA4-associated pathology. Copyright 2004 S. Karger AG, Basel

Chronic pancreatitis with pancreaticolithiasis and pseudocyst in a 5-year-old boy with homozygous SPINK1 mutation

Energy Technology Data Exchange (ETDEWEB)

Kuehn, Axel C.; Hirsch, Wolfgang [University of Leipzig, Department of Diagnostic Radiology - Pediatric Radiology, Faculty of Medicine, Leipzig (Germany); Teich, Niels; Caca, Karel [University of Leipzig, Department of Internal Medicine II - Gastroenterology / Hepatology, Faculty of Medicine, Leipzig (Germany); Limbach, Anne [University of Leipzig, Department of Pediatrics, Faculty of Medicine, Leipzig (Germany)

2005-09-01

We report a 5-year-old boy with a 5-month history of symptoms owing to chronic pancreatitis. Abdominal imaging revealed a large pseudocyst in the pancreatic tail and concretions in the main pancreatic duct. Successful endoscopic papillotomy and stent implantation were performed. Genetic testing showed homozygous SPINK1-N34S mutation, which is an established risk factor for chronic pancreatitis. (orig.)

Chronic pancreatitis with pancreaticolithiasis and pseudocyst in a 5-year-old boy with homozygous SPINK1 mutation

International Nuclear Information System (INIS)

Kuehn, Axel C.; Hirsch, Wolfgang; Teich, Niels; Caca, Karel; Limbach, Anne

2005-01-01

We report a 5-year-old boy with a 5-month history of symptoms owing to chronic pancreatitis. Abdominal imaging revealed a large pseudocyst in the pancreatic tail and concretions in the main pancreatic duct. Successful endoscopic papillotomy and stent implantation were performed. Genetic testing showed homozygous SPINK1-N34S mutation, which is an established risk factor for chronic pancreatitis. (orig.)

Homozygous mutations in the Fhit gene results in resistance to ionizing radiation and inhibition of apoptosis

International Nuclear Information System (INIS)

Turner, B.C.; Potoczek, M.B.; Ottey, M.; Croce, C.M.; Huebner, K.

2001-01-01

Purpose: The Fhit gene was identified because it represents the most active constitutive chromosome fragile site and has functions often associated with a tumor suppressor gene. Mutations in the Fhit locus have been identified in many cancer-derived cell lines, primary human tumors including lung, head and neck, colon, breast, and esophagus, and are associated with tobacco-induced lung cancers. In this study, we examined the cellular response of mouse epithelial cells with complete loss of Fhit to therapeutic doses of ionizing radiation and the prognostic importance of Fhit protein in early stage breast cancer patients treated with breast conserving therapy. Materials and Methods: Mouse epithelial cell lines containing either homozygous mutant Fhit -/- or wild-type Fhit +/+ were derived from mice (C57BL/6J X 129/SvJ) with either wild-type or inactivated Fhit gene. Clonogenic cell survival assays were carried out on subconfluent cells in logarithmic growth using a 137 Cs irradiator and survival curves were plotted as the log of the surviving cells versus dose and corrected for cloning efficiency. Apoptosis following ionizing radiation was determined by flow cytometry using the Annexin-V FITC kit and DAPI staining. Paraffin-embedded breast tumor blocks were obtained from 42 women with local breast tumor recurrence and 42 matched breast cancer patients without local cancer relapse treated with breast conserving therapy and stained with a 1:4000 dilution of polyclonal antibody to the Fhit protein and scored based on both intensity and distribution of Fhit staining within the invasive breast cancer component. Results: Treatment of Fhit -/- mouse epithelial cells with single fraction doses of ionizing radiation including 2, 4, 6, and 10 Gy result in 4-6 fold increase in cellular survival compared with isogenic parental cells from Fhit +/+ mice. Fhit -/- epithelial cells displayed 3-5 fold lower levels of apoptosis in response to both low and high doses of ionizing

Biallelic germline and somatic mutations in malignant mesothelioma: multiple mutations in transcription regulators including mSWI/SNF genes.

Science.gov (United States)

Yoshikawa, Yoshie; Sato, Ayuko; Tsujimura, Tohru; Otsuki, Taiichiro; Fukuoka, Kazuya; Hasegawa, Seiki; Nakano, Takashi; Hashimoto-Tamaoki, Tomoko

2015-02-01

We detected low levels of acetylation for histone H3 tail lysines in malignant mesothelioma (MM) cell lines resistant to histone deacetylase inhibitors. To identify the possible genetic causes related to the low histone acetylation levels, whole-exome sequencing was conducted with MM cell lines established from eight patients. A mono-allelic variant of BRD1 was common to two MM cell lines with very low acetylation levels. We identified 318 homozygous protein-damaging variants/mutations (18-78 variants/mutations per patient); annotation analysis showed enrichment of the molecules associated with mammalian SWI/SNF (mSWI/SNF) chromatin remodeling complexes and co-activators that facilitate initiation of transcription. In seven of the patients, we detected a combination of variants in histone modifiers or transcription factors/co-factors, in addition to variants in mSWI/SNF. Direct sequencing showed that homozygous mutations in SMARCA4, PBRM1 and ARID2 were somatic. In one patient, homozygous germline variants were observed for SMARCC1 and SETD2 in chr3p22.1-3p14.2. These exhibited extended germline homozygosity and were in regions containing somatic mutations, leading to a loss of BAP1 and PBRM1 expression in MM cell line. Most protein-damaging variants were heterozygous in normal tissues. Heterozygous germline variants were often converted into hemizygous variants by mono-allelic deletion, and were rarely homozygous because of acquired uniparental disomy. Our findings imply that MM might develop through the somatic inactivation of mSWI/SNF complex subunits and/or histone modifiers, including BAP1, in subjects that have rare germline variants of these transcription regulators and/or transcription factors/co-factors, and in regions prone to mono-allelic deletion during oncogenesis. © 2014 UICC.

Sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO) in a sibling pair with a homozygous p.A467T POLG mutation.

LENUS (Irish Health Repository)

McHugh, John C

2012-02-01

Two siblings who developed fifth-decade-onset, concurrent progressive sensory ataxia, dysarthria, and ophthalmoparesis were found to be homozygous for the p.A467T mutation of the polymerase gamma (POLG) gene. The clinical course in both subjects was progression to severe disability. The enlarging spectrum of sensory ataxic neuropathies associated with mitochondrial DNA (mtDNA) instability and POLG mutations should be recognized and considered in the differential diagnosis of this unusual presentation.

Phenotypes in siblings with homozygous mutations of TRAPPC9 and/or MCPH1 support a bifunctional model of MCPH1.

Science.gov (United States)

Duerinckx, Sarah; Meuwissen, Marije; Perazzolo, Camille; Desmyter, Laurence; Pirson, Isabelle; Abramowicz, Marc

2018-04-24

Autosomal recessive intellectual disability (ARID) is vastly heterogeneous. Truncating mutations of TRAPPC9 were reported in 8 ARID families. Autosomal recessive primary microcephaly (MCPH) represents another subgroup of ARID, itself very heterogeneous, where the size of the brain is very small since birth. MCPH1 plays a role at the centrosome via a BRCT1 domain, and in DNA Damage Repair (DDR) via BRCT2 and BRCT3, and it is not clear which of these two mechanisms causes MCPH in man. We studied the phenotype and sequenced the exome in two siblings with MCPH and their unaffected sister. Homozygous mutations of TRAPPC9 (p.Leu178Pro) and of MCPH1 (p.Arg741X) were found in both affected siblings. Brain MRI showed anomalies previously associated with TRAPPC9 defects, supporting the implication of TRAPPC9 in the phenotype. Importantly, the asymptomatic sister with normal head size was homozygous for the MCPH1 truncating mutation and heterozygous for the TRAPPC9 mutation. The affected siblings represent the first ARID cases with a TRAPPC9 missense mutation and with microcephaly of prenatal onset of. Furthermore, their unaffected sister represents strong evidence that the lack of MCPH1 BRCT3 domain does not cause MCPH in man, supporting a bifunctional model of MCPH1 where the centrosomal function is involved in brain volumic development and not the DDR function. © 2018 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.

Acral peeling skin syndrome resulting from a homozygous nonsense mutation in the CSTA gene encoding cystatin A.

Science.gov (United States)

Krunic, Aleksandar L; Stone, Kristina L; Simpson, Michael A; McGrath, John A

2013-01-01

Acral peeling skin syndrome (APSS) is a clinically and genetically heterogeneous disorder. We used whole-exome sequencing to identify the molecular basis of APSS in a consanguineous Jordanian-American pedigree. We identified a homozygous nonsense mutation (p.Lys22X) in the CSTA gene, encoding cystatin A, that was confirmed using Sanger sequencing. Cystatin A is a protease inhibitor found in the cornified cell envelope, and loss-of-function mutations have previously been reported in two cases of exfoliative ichthyosis. Our study expands the molecular pathology of APSS and demonstrates the value of next-generation sequencing in the genetic characterization of inherited skin diseases. © 2013 Wiley Periodicals, Inc.

Identification of a novel WFS1 homozygous nonsense mutation in Jordanian children with Wolfram syndrome.

Science.gov (United States)

Bodoor, Khaldon; Batiha, Osama; Abu-Awad, Ayman; Al-Sarihin, Khaldon; Ziad, Haya; Jarun, Yousef; Abu-Sheikha, Aya; Abu Jalboush, Sara; Alibrahim, Khoulod S

2016-09-01

Wolfram syndrome (WS) is a rare autosomal recessive neurodegenerative disorder characterized by the presentation of early onset type I diabetes mellitus and optic atrophy with later onset diabetes insipidus and deafness. WFS1 gene was identified on chromosome 4p16.1 as the gene responsible for WS disease given that most of the WS patients were found to carry mutations in this gene. This study was carried out to investigate the molecular spectrum of WFS1 gene in Jordanian families. Molecular and clinical characterization was performed on five WS patients from two unrelated Jordanian families. Our data indicated that WS patients of the first family harbored two deletion mutations (V415del and F247fs) located in exon 8 and exon 7 respectively, with a compound heterozygous pattern of inheritance; while in the second family, we identified a novel nonsense mutation (W185X) located in exon 5 in the N-terminal cytoplasmic domain with a homozygous pattern of inheritance. This mutation can be considered as loss of function mutation since the resulting truncated protein lost both the transmembrane domain and the C-terminal domain. Additionally, the W185X mutation lies within the CaM binding domain in wolframin protein which is thought to have a role in the regulation of wolframin function in response to calcium levels.

Seemingly neutral polymorphic variants may confer immunity to splicing-inactivating mutations

DEFF Research Database (Denmark)

Nielsen, Karsten Bork; Sørensen, Suzette; Cartegni, Luca

2007-01-01

assays to show that a missense mutation in exon 5 of the medium-chain acyl-CoA dehydrogenase (MCAD) gene primarily causes exon skipping by inactivating a crucial exonic splicing enhancer (ESE), thus leading to loss of a functional protein and to MCAD deficiency. This ESE functions by antagonizing...

Inactivation of protein translocation by cold-sensitive mutations in the yajC-secDF operon

NARCIS (Netherlands)

Nouwen, N; Driessen, AJM

2005-01-01

Most mutations in the yajC-secDF operon identified via genetic screens confer a cold-sensitive growth phenotype. Here we report that two of these mutations confer this cold-sensitive phenotype by inactivating the SecDF-YajC complex in protein translocation.

TP53 p.R337H is a conditional cancer-predisposing mutation: further evidence from a homozygous patient

International Nuclear Information System (INIS)

Giacomazzi, Juliana; Hainaut, Pierre; Ashton-Prolla, Patricia; Selistre, Simone; Duarte, Juliana; Ribeiro, Jorge Pinto; Vieira, Paulo JC; Souza Macedo, Gabriel de; Rossi, Cristina; Czepielewski, Mauro; Netto, Cristina Brinkmann Oliveira

2013-01-01

Adrenocortical carcinomas (ACCs) are among the most common childhood cancers occurring in infants affected with the Li-Fraumeni and Li- Fraumeni-like (LFS/LFL) syndromes, which are caused by dominant germline mutations in the TP53 gene. In Brazil, a particular mutation, occurring in the tetramerisation domain of the gene, p.R337H, is exceedingly common due to a founder effect and is strongly associated with ACC. In this report, we describe the phenotype and long-term clinical follow-up of a female child diagnosed with ACC and homozygous for the TP53 p.R337H founder mutation. At age 11 months, the patient was diagnosed with a virilising anaplastic adrenal cortical tumour, which was completely excised without disturbing the adrenal capsule. Family history was consistent with an LFL tumour pattern, and genotyping identified the TP53 p.R337H mutation in both alleles in genomic DNA from lymphocytes and fibroblasts. Haplotype analysis confirmed the occurrence of the mutation in the same founder haplotype previously described in other Brazilian patients. No other germline or somatic TP53 mutations or rearrangements were identified. At age 9 years, the child was asymptomatic and had no evidence of endocrine derangements. Full body and brain magnetic resonance imaging (MRI) failed to detect any suspicious proliferative lesions, and cardiopulmonary exercise testing results were within the normal reference for the child’s age, ruling out a major exercise capacity deficiency. This is the first clinical and aerobic functional capacity documentation of a patient who carries two mutant TP53 alleles and no wild-type allele. Our results support the hypothesis that TP53 p.R337H, the most common TP53 mutation ever described in any population, is a conditional mutant. Furthermore, our observations over a long period of clinical follow-up suggest that TP53 p.R337H homozygotes do not have a more severe disease phenotype than do heterozygote carriers of the same mutation. Patients with

A Novel Homozygous Missense Mutation in HOXC13 Leads to Autosomal Recessive Pure Hair and Nail Ectodermal Dysplasia.

Science.gov (United States)

Li, Xiaoxiao; Orseth, Meredith Lee; Smith, J Michael; Brehm, Mary Abigail; Agim, Nnenna Gebechi; Glass, Donald Alexander

2017-03-01

Pure hair and nail ectodermal dysplasia (PHNED) is a rare disorder that presents with hypotrichosis and nail dystrophy while sparing other ectodermal structures such as teeth and sweat glands. We describe a homozygous novel missense mutation in the HOXC13 gene that resulted in autosomal recessive PHNED in a Hispanic child. The mutation c.812A>G (p.Gln271Arg) is located within the DNA-binding domain of the HOXC13 gene, cosegregates within the family, and is predicted to be maximally damaging. This is the first reported case of a missense HOXC13 mutation resulting in PHNED and the first reported case of PHNED identified in a North American family. Our findings illustrate the critical role of HOXC13 in human hair and nail development. © 2017 Wiley Periodicals, Inc.

Key tumor suppressor genes inactivated by "greater promoter" methylation and somatic mutations in head and neck cancer

NARCIS (Netherlands)

Guerrero-Preston, Rafael; Michailidi, Christina; Marchionni, Luigi; Pickering, Curtis R.; Frederick, Mitchell J.; Myers, Jeffrey N.; Yegnasubramanian, Srinivasan; Hadar, Tal; Noordhuis, Maartje G.; Zizkova, Veronika; Fertig, Elana; Agrawal, Nishant; Westra, William; Koch, Wayne; Califano, Joseph; Velculescu, Victor E.; Sidransky, David

Tumor suppressor genes (TSGs) are commonly inactivated by somatic mutation and/or promoter methylation; yet, recent high-throughput genomic studies have not identified key TSGs inactivated by both mechanisms. We pursued an integrated molecular analysis based on methylation binding domain sequencing

Inactivating Mutation screening of Exon 6 and Exon 10E of FSHR gene in women with Polycystic Ovarian Syndrome in Vellore population

Science.gov (United States)

Sekar, Nishu; Sapre, Madhura; Kale, Vaikhari; Prabhu, Yogamaya D.; Renu, Kaviyarasi; Ramgir, Shalaka S.; Abilash, V. G.

2017-11-01

Polycystic Ovarian syndrome (PCOS) is a major cause of infertility in females of reproducing age and is typified by oligo-anovulation, hyperandrogenism, hirsutism and polycystic ovaries. FSHR gene located on chromosome 2 p21 is responsible for the normal follicular development and any deletion or mutation in the gene affects the interaction of FSH with its receptor. Thus, it becomes the candidate gene for PCOS study. Inactivating mutation in FSHR gene limits the receptor’s function by creating a complete block, changing the receptor-ligand complex or the basic hormone signal transduction.To screen the inactivating mutations in Exon 6 and Exon 10E of FSHR gene in women diagnosed with PCOS.PCR-RFLP analysis indicated that there were no inactivating mutations found in Exon 6 and Exon 10E. Variations in hormone levels were seen amongst the PCOS patients. There were no inactivating mutations found in FSHR gene of the women diagnosed with PCOS according to the Rotterdam criteria in Vellore population.

Severe coagulation factor VII deficiency caused by a novel homozygous mutation (p. Trp284Gly) in loop 140s.

Science.gov (United States)

Hao, Xiuping; Cheng, XiaoLi; Ye, Jiajia; Wang, Yingyu; Yang, LiHong; Wang, Mingshan; Jin, Yanhui

2016-06-01

Congenital coagulation factor VII (FVII) deficiency is a rare disorder caused by mutation in F7 gene. Herein, we reported a patient who had unexplained hematuria and vertigo with consanguineous parents. He has been diagnosed as having FVII deficiency based on the results of reduced FVII activity (2.0%) and antigen (12.8%). The thrombin generation tests verified that the proband has obstacles in producing thrombin. Direct sequencing analysis revealed a novel homozygous missense mutation p.Trp284Gly. Also noteworthy is the fact that the mutational residue belongs to structurally conserved loop 140s, which majorly undergo rearrangement after FVII activation. Model analysis indicated that the substitution disrupts these native hydrophobic interactions, which are of great importance to the conformation in the activation domain of FVIIa.

Novel homozygous VHL mutation in exon 2 is associated with congenital polycythemia but not with cancer.

Science.gov (United States)

Lanikova, Lucie; Lorenzo, Felipe; Yang, Chunzhang; Vankayalapati, Hari; Drachtman, Richard; Divoky, Vladimir; Prchal, Josef T

2013-05-09

Germline von Hippel-Lindau (VHL) gene mutations underlie dominantly inherited familial VHL tumor syndrome comprising a predisposition for renal cell carcinoma, pheochromocytoma/paraganglioma, cerebral hemangioblastoma, and endolymphatic sac tumors. However, recessively inherited congenital polycythemia, exemplified by Chuvash polycythemia, has been associated with 2 separate 3' VHL gene mutations in exon 3. It was proposed that different positions of loss-of-function VHL mutations are associated with VHL syndrome cancer predisposition and only C-terminal domain-encoding VHL mutations would cause polycythemia. However, now we describe a new homozygous VHL exon 2 mutation of the VHL gene:(c.413C>T):P138L, which is associated in the affected homozygote with congenital polycythemia but not in her, or her-heterozygous relatives, with cancer or other VHL syndrome tumors. We show that VHL(P138L) has perturbed interaction with hypoxia-inducible transcription factor (HIF)1α. Further, VHL(P138L) protein has decreased stability in vitro. Similarly to what was reported in Chuvash polycythemia and some other instances of HIFs upregulation, VHL(P138L) erythroid progenitors are hypersensitive to erythropoietin. Interestingly, the level of RUNX1/AML1 and NF-E2 transcripts that are specifically upregulated in acquired polycythemia vera were also upregulated in VHL(P138L) granulocytes.

A novel homozygous mutation in the FSHR gene is causative for primary ovarian insufficiency.

Science.gov (United States)

Liu, Hongli; Xu, Xiaofei; Han, Ting; Yan, Lei; Cheng, Lei; Qin, Yingying; Liu, Wen; Zhao, Shidou; Chen, Zi-Jiang

2017-12-01

To identify the potential FSHR mutation in a Chinese woman with primary ovarian insufficiency (POI). Genetic and functional studies. University-based reproductive medicine center. A POI patient, her family members, and another 192 control women with regular menstruation. Ovarian biopsy was performed in the patient. Sanger sequencing was carried out for the patient, her sister, and parents. The novel variant identified was further confirmed with the use of control subjects. Sanger sequencing and genotype analysis to identify the potential variant of the FSHR gene; hematoxylin and eosin staining of the ovarian section to observe the follicular development; Western blotting and immunofluorescence to detect FSH receptor (FSHR) expression; and cyclic adenosine monophosphate (cAMP) assay to monitor FSH-induced signaling. Histologic examination of the ovaries in the patient revealed follicular development up to the early antral stage. Mutational screening and genotype analysis of the FSHR gene identified a novel homozygous mutation c.175C>T (p.R59X) in exon 2, which was inherited in the autosomal recessive mode from her heterozygous parents but was absent in her sister and the 192 control women. Functional studies demonstrated that in vitro the nonsense mutation caused the loss of full-length FSHR expression and that p.R59X mutant showed no response to FSH stimulation in the cAMP level. The mutation p.R59X in FSHR is causative for POI by means of arresting folliculogenesis. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Distinct Mutations Led to Inactivation of Type 1 Fimbriae Expression in Shigella spp.

Science.gov (United States)

Bravo, Verónica; Puhar, Andrea; Sansonetti, Philippe; Parsot, Claude; Toro, Cecilia S.

2015-01-01

Shigella spp. are responsible for bacillary dysentery in humans. The acquisition or the modification of the virulence plasmid encoding factors promoting entry of bacteria into and dissemination within epithelial cells was a critical step in the evolution of these bacteria from their Escherichia coli ancestor(s). Incorporation of genomic islands (GI) and gene inactivation also shaped interactions between these pathogens and their human host. Sequence analysis of the GI inserted next to the leuX tRNA gene in S. boydii, S. dysenteriae, S. flexneri, S. sonnei and enteroinvasive E. coli (EIEC) suggests that this region initially carried the fec, yjhATS and fim gene clusters. The fim cluster encoding type I fimbriae is systematically inactivated in both reference strains and clinical isolates and distinct mutations are responsible for this inactivation in at least three phylogenetic groups. To investigate consequences of the presence of fimbriae on the outcome of the interaction of Shigella with host cells, we used a S. flexneri strain harboring a plasmid encoding the E. coli fim operon. Production of fimbriae by this recombinant strain increased the ability of bacteria to adhere to and enter into epithelial cells and had no effect on their ability to disseminate from cell to cell. The observations that production of type I fimbriae increases invasion of epithelial cells and that independent mutations abolish fimbriae production in Shigella suggest that these mutations correspond to pathoadaptive events. PMID:25811616

Distinct mutations led to inactivation of type 1 fimbriae expression in Shigella spp.

Directory of Open Access Journals (Sweden)

Verónica Bravo

Full Text Available Shigella spp. are responsible for bacillary dysentery in humans. The acquisition or the modification of the virulence plasmid encoding factors promoting entry of bacteria into and dissemination within epithelial cells was a critical step in the evolution of these bacteria from their Escherichia coli ancestor(s. Incorporation of genomic islands (GI and gene inactivation also shaped interactions between these pathogens and their human host. Sequence analysis of the GI inserted next to the leuX tRNA gene in S. boydii, S. dysenteriae, S. flexneri, S. sonnei and enteroinvasive E. coli (EIEC suggests that this region initially carried the fec, yjhATS and fim gene clusters. The fim cluster encoding type I fimbriae is systematically inactivated in both reference strains and clinical isolates and distinct mutations are responsible for this inactivation in at least three phylogenetic groups. To investigate consequences of the presence of fimbriae on the outcome of the interaction of Shigella with host cells, we used a S. flexneri strain harboring a plasmid encoding the E. coli fim operon. Production of fimbriae by this recombinant strain increased the ability of bacteria to adhere to and enter into epithelial cells and had no effect on their ability to disseminate from cell to cell. The observations that production of type I fimbriae increases invasion of epithelial cells and that independent mutations abolish fimbriae production in Shigella suggest that these mutations correspond to pathoadaptive events.

Homozygous SLC6A17 Mutations Cause Autosomal-Recessive Intellectual Disability with Progressive Tremor, Speech Impairment, and Behavioral Problems

Science.gov (United States)

Iqbal, Zafar; Willemsen, Marjolein H.; Papon, Marie-Amélie; Musante, Luciana; Benevento, Marco; Hu, Hao; Venselaar, Hanka; Wissink-Lindhout, Willemijn M.; Vulto-van Silfhout, Anneke T.; Vissers, Lisenka E.L.M.; de Brouwer, Arjan P.M.; Marouillat, Sylviane; Wienker, Thomas F.; Ropers, Hans Hilger; Kahrizi, Kimia; Nadif Kasri, Nael; Najmabadi, Hossein; Laumonnier, Frédéric; Kleefstra, Tjitske; van Bokhoven, Hans

2015-01-01

We report on Dutch and Iranian families with affected individuals who present with moderate to severe intellectual disability and additional phenotypes including progressive tremor, speech impairment, and behavioral problems in certain individuals. A combination of exome sequencing and homozygosity mapping revealed homozygous mutations c.484G>A (p.Gly162Arg) and c.1898C>G (p.Pro633Arg) in SLC6A17. SLC6A17 is predominantly expressed in the brain, encodes a synaptic vesicular transporter of neutral amino acids and glutamate, and plays an important role in the regulation of glutamatergic synapses. Prediction programs and 3D modeling suggest that the identified mutations are deleterious to protein function. To directly test the functional consequences, we investigated the neuronal subcellular localization of overexpressed wild-type and mutant variants in mouse primary hippocampal neuronal cells. Wild-type protein was present in soma, axons, dendrites, and dendritic spines. p.Pro633Arg altered SLC6A17 was found in soma and proximal dendrites but did not reach spines. p.Gly162Arg altered SLC6A17 showed a normal subcellular distribution but was associated with an abnormal neuronal morphology mainly characterized by the loss of dendritic spines. In summary, our genetic findings implicate homozygous SLC6A17 mutations in autosomal-recessive intellectual disability, and their pathogenic role is strengthened by genetic evidence and in silico and in vitro functional analyses. PMID:25704603

Adult siblings with homozygous G6PC3 mutations expand our understanding of the severe congenital neutropenia type 4 (SCN4 phenotype

Directory of Open Access Journals (Sweden)

Fernandez Bridget A

2012-11-01

Full Text Available Abstract Background Severe congenital neutropenia type 4 (SCN4 is an autosomal recessive disorder caused by mutations in the third subunit of the enzyme glucose-6-phosphatase (G6PC3. Its core features are congenital neutropenia and a prominent venous skin pattern, and affected individuals have variable birth defects. Oculocutaneous albinism type 4 (OCA4 is caused by autosomal recessive mutations in SLC45A2. Methods We report a sister and brother from Newfoundland, Canada with complex phenotypes. The sister was previously reported by Cullinane et al., 2011. We performed homozygosity mapping, next generation sequencing and conventional Sanger sequencing to identify mutations that cause the phenotype in this family. We have also summarized clinical data from 49 previously reported SCN4 cases with overlapping phenotypes and interpret the medical histories of these siblings in the context of the literature. Results The siblings’ phenotype is due in part to a homozygous mutation in G6PC3, [c.829C > T, p.Gln277X]. Their ages are 38 and 37 years respectively and they are the oldest SCN4 patients published to date. Both presented with congenital neutropenia and later developed Crohn disease. We suggest that the latter is a previously unrecognized SCN4 manifestation and that not all affected individuals have an intellectual disability. The sister also has a homozygous mutation in SLC45A2, which explains her severe oculocutaneous hypopigmentation. Her brother carried one SLC45A2 mutation and was diagnosed with “partial OCA” in childhood. Conclusions This family highlights that apparently novel syndromes can in fact be caused by two known autosomal recessive disorders.

The spectrum of ABCC8 mutations in Norwegian patients with congenital hyperinsulinism of infancy

DEFF Research Database (Denmark)

Sandal, T; Laborie, L B; Brusgaard, K

2009-01-01

and two families, respectively. KCNJ11 mutations were not found in any patients. Based on our mutation screening, we estimate the minimum birth prevalence of ABCC8-CHI in Norway to 1:70,000 during the past decade. Our results considerably extend the knowledge of the molecular genetics behind CHI...... channel KIR6.2, which are encoded by the genes ABCC8 and KCNJ11, respectively. Activating mutations in the subunit genes can result in monogenic diabetes, whereas inactivating mutations are the most common cause of congenital hyperinsulinism of infancy (CHI). Twenty-six Norwegian probands with CHI were...... analyzed for alterations in ABCC8 and KCNJ11. Fifteen probands (58%) had mutations in the ABCC8 gene. Nine patients were homozygous or compound heterozygous for the mutations, indicating diffuse pancreatic disease. In five patients, heterozygous and paternally inherited mutations were found, suggesting...

A Catalog of Genes Homozygously Deleted in Human Lung Cancer and the Candidacy of PTPRD as a Tumor Suppressor Gene

Science.gov (United States)

Kohno, Takashi; Otsuka, Ayaka; Girard, Luc; Sato, Masanori; Iwakawa, Reika; Ogiwara, Hideaki; Sanchez-Cespedes, Montse; Minna, John D.; Yokota, Jun

2010-01-01

A total of 176 genes homozygously deleted in human lung cancer were identified by DNA array-based whole genome scanning of 52 lung cancer cell lines and subsequent genomic PCR in 74 cell lines, including the 52 cell lines scanned. One or more exons of these genes were homozygously deleted in one (1%) to 20 (27%) cell lines. These genes included known tumor suppressor genes, e.g., CDKN2A/p16, RB1, and SMAD4, and candidate tumor suppressor genes whose hemizygous or homozygous deletions were reported in several types of human cancers, such as FHIT, KEAP1, and LRP1B/LRP-DIP. CDKN2A/p16 and p14ARF located in 9p21 were most frequently deleted (20/74, 27%). The PTPRD gene was most frequently deleted (8/74, 11%) among genes mapping to regions other than 9p21. Somatic mutations, including a nonsense mutation, of the PTPRD gene were detected in 8/74 (11%) of cell lines and 4/95 (4%) of surgical specimens of lung cancer. Reduced PTPRD expression was observed in the majority (>80%) of cell lines and surgical specimens of lung cancer. Therefore, PTPRD is a candidate tumor suppressor gene in lung cancer. Microarray-based expression profiling of 19 lung cancer cell lines also indicated that some of the 176 genes, such as KANK and ADAMTS1, are preferentially inactivated by epigenetic alterations. Genetic/epigenetic as well as functional studies of these 176 genes will increase our understanding of molecular mechanisms behind lung carcinogenesis. PMID:20073072

Mutation formation and inactivation of mammalian cells by heavy ions. 3

International Nuclear Information System (INIS)

Obaturov, G.M.

1984-01-01

Using parameter values of equations for cell inactivation cross-sections, theoretical curves were calculated for cell radiosensitivity (α 1 ) in dependence on LET. There is good agreement between calculated and experimental values of α 1 . The yield of lethal mutations of 1st and 2nd types and their sum in dependence on LET was also calculated. It was shown that for low LET ions cell radiosensitivity is caused by the 2nd type of mutation, independent of LET, proportional to DNA mass and inversely proportional to repair rate. For high LET ions when lethal mutation number per one track is more than one, α 1 is caused by the 1st type of mutation, proportional to cell nuclear cross-section and inversely proportional to LET. For intermediate LET ions α 1 is a complicated function of LET. It is follows from the equations that more than 17% of double strand breaks (DSB) take part in lethal mutation formation. Others are either repaired or formed in the process of experimentally determined DSB yield. (author)

Novel biallelic mutations in MSH6 and PMS2 genes: gene conversion as a likely cause of PMS2 gene inactivation.

Science.gov (United States)

Auclair, Jessie; Leroux, Dominique; Desseigne, Françoise; Lasset, Christine; Saurin, Jean Christophe; Joly, Marie Odile; Pinson, Stéphane; Xu, Xiao Li; Montmain, Gilles; Ruano, Eric; Navarro, Claudine; Puisieux, Alain; Wang, Qing

2007-11-01

Since the first report by our group in 1999, more than 20 unrelated biallelic mutations in DNA mismatch repair genes (MMR) have been identified. In the present report, we describe two novel cases: one carrying compound heterozygous mutations in the MSH6 gene; and the other, compound heterozygous mutations in the PMS2 gene. Interestingly, the inactivation of one PMS2 allele was likely caused by gene conversion. Although gene conversion has been suggested to be a mutation mechanism underlying PMS2 inactivation, this is the first report of its involvement in a pathogenic mutation. The clinical features of biallelic mutation carriers were similar to other previously described patients, with the presence of café-au-lait spots (CALS), early onset of brain tumors, and colorectal neoplasia. Our data provide further evidence of the existence, although rare, of a distinct recessively inherited syndrome on the basis of MMR constitutional inactivation. The identification of this syndrome should be useful for genetic counseling, especially in families with atypical hereditary nonpolyposis colon cancer (HNPCC) associated with childhood cancers, and for the clinical surveillance of these mutation carriers. 2007 Wiley-Liss, Inc.

Homozygous SLC6A17 mutations cause autosomal-recessive intellectual disability with progressive tremor, speech impairment, and behavioral problems.

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Iqbal, Zafar; Willemsen, Marjolein H; Papon, Marie-Amélie; Musante, Luciana; Benevento, Marco; Hu, Hao; Venselaar, Hanka; Wissink-Lindhout, Willemijn M; Vulto-van Silfhout, Anneke T; Vissers, Lisenka E L M; de Brouwer, Arjan P M; Marouillat, Sylviane; Wienker, Thomas F; Ropers, Hans Hilger; Kahrizi, Kimia; Nadif Kasri, Nael; Najmabadi, Hossein; Laumonnier, Frédéric; Kleefstra, Tjitske; van Bokhoven, Hans

2015-03-05

We report on Dutch and Iranian families with affected individuals who present with moderate to severe intellectual disability and additional phenotypes including progressive tremor, speech impairment, and behavioral problems in certain individuals. A combination of exome sequencing and homozygosity mapping revealed homozygous mutations c.484G>A (p.Gly162Arg) and c.1898C>G (p.Pro633Arg) in SLC6A17. SLC6A17 is predominantly expressed in the brain, encodes a synaptic vesicular transporter of neutral amino acids and glutamate, and plays an important role in the regulation of glutamatergic synapses. Prediction programs and 3D modeling suggest that the identified mutations are deleterious to protein function. To directly test the functional consequences, we investigated the neuronal subcellular localization of overexpressed wild-type and mutant variants in mouse primary hippocampal neuronal cells. Wild-type protein was present in soma, axons, dendrites, and dendritic spines. p.Pro633Arg altered SLC6A17 was found in soma and proximal dendrites but did not reach spines. p.Gly162Arg altered SLC6A17 showed a normal subcellular distribution but was associated with an abnormal neuronal morphology mainly characterized by the loss of dendritic spines. In summary, our genetic findings implicate homozygous SLC6A17 mutations in autosomal-recessive intellectual disability, and their pathogenic role is strengthened by genetic evidence and in silico and in vitro functional analyses. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

A homozygous PMS2 founder mutation with an attenuated constitutional mismatch repair deficiency phenotype.

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Li, Lili; Hamel, Nancy; Baker, Kristi; McGuffin, Michael J; Couillard, Martin; Gologan, Adrian; Marcus, Victoria A; Chodirker, Bernard; Chudley, Albert; Stefanovici, Camelia; Durandy, Anne; Hegele, Robert A; Feng, Bing-Jian; Goldgar, David E; Zhu, Jun; De Rosa, Marina; Gruber, Stephen B; Wimmer, Katharina; Young, Barbara; Chong, George; Tischkowitz, Marc D; Foulkes, William D

2015-05-01

Inherited mutations in DNA mismatch repair genes predispose to different cancer syndromes depending on whether they are mono-allelic or bi-allelic. This supports a causal relationship between expression level in the germline and phenotype variation. As a model to study this relationship, our study aimed to define the pathogenic characteristics of a recurrent homozygous coding variant in PMS2 displaying an attenuated phenotype identified by clinical genetic testing in seven Inuit families from Northern Quebec. Pathogenic characteristics of the PMS2 mutation NM_000535.5:c.2002A>G were studied using genotype-phenotype correlation, single-molecule expression detection and single genome microsatellite instability analysis. This PMS2 mutation generates a de novo splice site that competes with the authentic site. In homozygotes, expression of the full-length protein is reduced to a level barely detectable by conventional diagnostics. Median age at primary cancer diagnosis is 22 years among 13 NM_000535.5:c.2002A>G homozygotes, versus 8 years in individuals carrying bi-allelic truncating mutations. Residual expression of full-length PMS2 transcript was detected in normal tissues from homozygotes with cancers in their 20s. Our genotype-phenotype study of c.2002A>G illustrates that an extremely low level of PMS2 expression likely delays cancer onset, a feature that could be exploited in cancer preventive intervention. 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.

Somatic INK4a-ARF locus mutations: a significant mechanism of gene inactivation in squamous cell carcinomas of the head and neck.

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Poi, M J; Yen, T; Li, J; Song, H; Lang, J C; Schuller, D E; Pearl, D K; Casto, B C; Tsai, M D; Weghorst, C M

2001-01-01

The INK4a-ARF locus is located on human chromosome 9p21 and is known to encode two functionally distinct tumor-suppressor genes. The p16(INK4a) (p16) tumor-suppressor gene product is a negative regulator of cyclin-dependent kinases 4 and 6, which in turn positively regulate progression of mammalian cells through the cell cycle. The p14(ARF) tumor-suppressor gene product specifically interacts with human double minute 2, leading to the subsequent stabilization of p53 and G(1) arrest. Previous investigations analyzing the p16 gene in squamous cell carcinomas of the head and neck (SCCHNs) have suggested the predominate inactivating events to be homozygous gene deletions and hypermethylation of the p16 promoter. Somatic mutational inactivation of p16 has been reported to be low (0-10%, with a combined incidence of 25 of 279, or 9%) and to play only a minor role in the development of SCCHN. The present study examined whether this particular mechanism of INK4a/ARF inactivation, specifically somatic mutation, has been underestimated in SCCHN by determining the mutational status of the p16 and p14(ARF) genes in 100 primary SCCHNs with the use of polymerase chain reaction technology and a highly sensitive, nonradioactive modification of single-stranded conformational polymorphism (SSCP) analysis termed "cold" SSCP. Exons 1alpha, 1beta, and 2 of INK4a/ARF were amplified using intron-based primers or a combination of intron- and exon-based primers. A total of 27 SCCHNs (27%) exhibited sequence alterations in this locus, 22 (22%) of which were somatic sequence alterations and five (5%) of which were a single polymorphism in codon 148. Of the 22 somatic alterations, 20 (91%) directly or indirectly involved exon 2, and two (9%) were located within exon 1alpha. No mutations were found in exon 1beta. All 22 somatic mutations would be expected to yield altered p16 proteins, but only 15 of them should affect p14(ARF) proteins. Specific somatic alterations included microdeletions or

Craniofacial abnormalities in homozygous Small eye (Sey/Sey) embryos and newborn mice.

OpenAIRE

Kaufman, M H; Chang, H H; Shaw, J P

1995-01-01

The Small eye (Sey) gene in the mouse is lethal in the homozygous state. It is located on chromosome 2, is a mutation in the Pax-6 gene, and is genetically homologous with the human aniridia 2 (AN2) gene mutation. Numerous studies over the last few years, using genetic and molecular biological approaches, have investigated both the location of the gene as well as its possible mode of action. In the homozygous state, the primary defect appears to be limited to the failure of differentiation of...

Analysis of Transcription Factors Key for Mouse Pancreatic Development Establishes NKX2-2 and MNX1 Mutations as Causes of Neonatal Diabetes in Man

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Flanagan, Sarah E.; De Franco, Elisa; Lango Allen, Hana; Zerah, Michele; Abdul-Rasoul, Majedah M.; Edge, Julie A.; Stewart, Helen; Alamiri, Elham; Hussain, Khalid; Wallis, Sam; de Vries, Liat; Rubio-Cabezas, Oscar; Houghton, Jayne A.L.; Edghill, Emma L.; Patch, Ann-Marie; Ellard, Sian; Hattersley, Andrew T.

2014-01-01

Summary Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development. PMID:24411943

On the effect of certain mutations on the radiosensitivity of haploid and diploid yeast cells

International Nuclear Information System (INIS)

Sokurova, E.N.; Korogodin, V.I.

1978-01-01

Mutation ade 1-6 in haploid cell Saccharomyces cerevisiae increases half as much against radioresistance of cells. Diploid cells lacking in adenine, homozygous by ade 1-6 mutation, are nearly twice as radiosensitive as prototrophic cells. Hence ade 1-6 mutation increases radioresistance of haploid cells and decreases that of diplois. These changes in radioresistance are not connected with variations in the extrapolation number of survival curve, the ability of cells to recover from radiation damages upon cultivation in an innutrient medium, and with the inactivation form ratio. Lack of adenine influences the radioresistance of diploid yeast irrespective of whether it is or it is not affected by homo- or heterozygosity by the locus of mating type

Homozygous SLC6A17 Mutations Cause Autosomal-Recessive Intellectual Disability with Progressive Tremor, Speech Impairment, and Behavioral Problems

OpenAIRE

Iqbal, Zafar; Willemsen, Marjolein H.; Papon, Marie-Amélie; Musante, Luciana; Benevento, Marco; Hu, Hao; Venselaar, Hanka; Wissink-Lindhout, Willemijn M.; Vulto-van Silfhout, Anneke T.; Vissers, Lisenka E.L.M.; de Brouwer, Arjan P.M.; Marouillat, Sylviane; Wienker, Thomas F.; Ropers, Hans Hilger; Kahrizi, Kimia

2015-01-01

We report on Dutch and Iranian families with affected individuals who present with moderate to severe intellectual disability and additional phenotypes including progressive tremor, speech impairment, and behavioral problems in certain individuals. A combination of exome sequencing and homozygosity mapping revealed homozygous mutations c.484G>A (p.Gly162Arg) and c.1898C>G (p.Pro633Arg) in SLC6A17. SLC6A17 is predominantly expressed in the brain, encodes a synaptic vesicular transporter of neu...

Inactivation and mutation induction in Saccharomyces cerevisiae exposed to simulated sunlight: evaluation of action spectra.

Science.gov (United States)

Schenk-Meuser, K; Pawlowsky, K; Kiefer, J

1992-07-15

The effectiveness of polychromatic light irradiation was investigated for haploid yeast cells. Inactivation and mutation induction were measured in both a RAD-wildtype strain and an excision-repair defective strain. The behaviour of vegetative "wet" cells was compared to that of dehydrated cells. The aim of the study was to assess the interaction of UVC with other wavelengths in cells of different states of humidity. The irradiation procedure was therefore carried out using a solar simulator either with full spectrum or with a UVC-blocking filter (modified sunlight) added. The results were analysed on the basis of separately determined action spectra. The summation of the efficiency of individual wavelengths was compared to the values obtained from polychromatic irradiation. It is shown that the effects caused by the whole-spectrum irradiation in wet cells can be predicted sufficiently from the calculation, while dried wildtype cells exhibit higher mutation rates. Thus it can be assumed that drying-specific damage leads to lethal and mutagenic lesions which are processed in different ways, causing a synergistic behaviour in mutation induction. Irradiation of vegetative cells with modified sunlight (UVC-) results in less inactivation and lower mutation rates than were calculated. From these results it can be concluded that this antagonistic behaviour is caused by the interaction of near-UV photoproducts.

The homozygous VHL(D126N) missense mutation is associated with dramatically elevated erythropoietin levels, consequent polycythemia, and early onset severe pulmonary hypertension.

Science.gov (United States)

Sarangi, Susmita; Lanikova, Lucie; Kapralova, Katarina; Acharya, Suchitra; Swierczek, Sabina; Lipton, Jeffrey M; Wolfe, Lawrence; Prchal, Josef T

2014-11-01

von Hippel-Lindau (VHL) protein is the principal negative regulator of hypoxia sensing mediated by transcription factors. Mutations in exon 3 of the VHL gene lead to Chuvash (VHL(R200W)) and Croatian (VHL(H191D)) polycythemias. Here, we describe an infant of Bangladesh ethnicity with a novel homozygous VHL(D126N) mutation with congenital polycythemia and dramatically elevated erythropoietin (EPO) levels, who developed severe fatal pulmonary hypertension. In contrast to Chuvash polycythemia, erythroid progenitors (BFU-Es) did not reveal a marked EPO hypersensitivity. Further, NF-E2 and RUNX1 transcripts that correlate with BFU-Es EPO hypersensitivity in polycythemic mutations were not elevated. © 2014 Wiley Periodicals, Inc.

Odonto-onycho-dermal dysplasia in a patient homozygous for a WNT10A nonsens mutation and mild manifestations of ectodermal dysplasia in carriers of the mutation

DEFF Research Database (Denmark)

Bruun Krøigård, Anne; Clemmensen, Ole; Gjørup, Hans

2016-01-01

was homozygous for a previously reported pathogenic mutation in the WNT10A gene, c.321C > A, p.Cys107*. The skin and nail abnormalities were for many years interpreted as psoriasis and treated accordingly. A thorough clinical examination revealed hypotrichosis and hyperhidrosis of the soles and dental...... history of tooth anomalies, this lead to the clinical suspicion of a hereditary ectodermal dysplasia. CONCLUSION: This case illustrates the challenges of diagnosing ectodermal dysplasia like OODD and highlights the relevance of interdisciplinary cooperation in the diagnosis of rare conditions....

Association of Exon 10A and 10B inactivating mutation of follicle stimulating hormone receptor gene (FSHR) and Polycystic Ovarian Syndrome in Vellore cohort

Science.gov (United States)

Sekar, Nishu; Kulkarni, Rucha; Ozalkar, Sharvari; Prabhu, Yogamaya D.; Renu, Kaviyarasi; Ramgir, Shalaka S.; Abilash, V. G.

2017-11-01

Polycystic ovarian syndrome is the most common heterogenous endocrine disorder in women. Follicle stimulating hormone receptor is associated with normal development as well as maturation of follicles and triggers estrogen production in granulosa cells of the ovary. Inactivating mutation in FSHR gene correlated with reduction of ovarian function in women is due to damage to receptor function. This study aims to investigate whether inactivating mutations, in follicle stimulating hormone receptor gene is related to polycystic ovarian morphology in women with PCOS. Genomic DNA isolated from 15 subjects from Sandhya Hospital, Vellore (10 patients with PCOS and 5 healthy controls) was taken for this study. Patient data included a clinical report, hormonal levels, and ovarian morphological details. DNA isolation was followed by DNA amplification by polymerase chain reaction using Exon 10 A and Exon 10 B primers. The PCR-RFLP analysis was performed using Dde1 restriction enzyme. Here we discuss inactivating mutation found in Exon 10 of FSHR gene in patients with PCOS.The absence of inactivating mutation was observed through PCR-RFLP study on Exon 10A and Exon 10B.

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

Directory of Open Access Journals (Sweden)

Hegele Robert A

2007-09-01

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

Risk scaling factors from inactivation to chromosome aberrations, mutations and oncogenic transformations in mammalian cells

International Nuclear Information System (INIS)

Alkaharam, A.S.; Watt, D.E.

1997-01-01

Analyses of bio-effect mechanisms of damage to mammalian cells in terms of the quality parameter 'mean free path for primary ionisation', for heavy charged particles, strongly suggests that there is a common mechanism for the biological endpoints of chromosome aberrations, mutations and oncogenic transformation. The lethal lesions are identified as unrepaired double-strand breaks in the intracellular DNA. As data for the various endpoints studied can be represented in a unified scheme, for any radiation type, it follows that radiation risk factors can be determined on the basis of simple ratios to the inactivation cross sections. There are intrinsic physical reasons why neutrons can never reach the saturation level of heavier particles for equal fluences. The probabilities of risk with respect to inactivation, for chromosome dicentrics, mutation of the HPRT gene and of oncogenic transformation are respectively 0.24, 5.8 x 10 -5 , and 4.1 x 10 -3 . (author)

Homozygous mutation of focal adhesion kinase in embryonic stem cell derived neurons: normal electrophysiological and morphological properties in vitro

Directory of Open Access Journals (Sweden)

Komiyama NH

2006-06-01

Full Text Available Abstract Background Genetically manipulated embryonic stem (ES cell derived neurons (ESNs provide a powerful system with which to study the consequences of gene manipulation in mature, synaptically connected neurons in vitro. Here we report a study of focal adhesion kinase (FAK, which has been implicated in synapse formation and regulation of ion channels, using the ESN system to circumvent the embryonic lethality of homozygous FAK mutant mice. Results Mouse ES cells carrying homozygous null mutations (FAK-/- were generated and differentiated in vitro into neurons. FAK-/- ESNs extended axons and dendrites and formed morphologically and electrophysiologically intact synapses. A detailed study of NMDA receptor gated currents and voltage sensitive calcium currents revealed no difference in their magnitude, or modulation by tyrosine kinases. Conclusion FAK does not have an obligatory role in neuronal differentiation, synapse formation or the expression of NMDA receptor or voltage-gated calcium currents under the conditions used in this study. The use of genetically modified ESNs has great potential for rapidly and effectively examining the consequences of neuronal gene manipulation and is complementary to mouse studies.

Lumacaftor/ivacaftor, a novel agent for the treatment of cystic fibrosis patients who are homozygous for the F580del CFTR mutation.

Science.gov (United States)

Bulloch, Marilyn N; Hanna, Cameron; Giovane, Richard

2017-10-01

Cystic Fibrosis (CF) is an autosomal recessive disease affecting up to 90,000 people worldwide. Approximately 73% of patients are homozygous for the F508del cystic fibrosis transmembrane conductance regulator [CFTR] mutation. Traditionally treatment has only included supportive care. Therefore, there is a need for safe and effective novel therapies targeting the underlying molecular defects seen with CF. Areas covered: In 2016, the Food and Drug Administration and the European Commission approved LUM/IVA (Orkambi), a CFTR modulator that includes both a CFTR corrector and potentiator, for CF patients homozygous for the F508del CFTR mutation. This article reviews the pharmacologic features, clinical efficacy, and safety of LUM/IVA and summarize the available pre-clinical and clinical data of LUM/IVA use. Expert commentary: LUM/IVA showed modest, but significant improvements from baseline in percent predicted FEV 1 (ppFEV 1 ) as well as a reduction in pulmonary exacerbations by 35% It was shown to be safe for short- and long-term use. Currently, LUM/IVA is the only oral agent in its class available and represents a milestone the development of therapies for the management of CF. Nonetheless, pharmacoeconomic data are necessary to justify its high cost before is use becomes standard of care.

Hypophosphatemic osteomalacia and bone sclerosis caused by a novel homozygous mutation of the FAM20C gene in an elderly man with a mild variant of Raine syndrome.

Science.gov (United States)

Takeyari, Shinji; Yamamoto, Takehisa; Kinoshita, Yuka; Fukumoto, Seiji; Glorieux, Francis H; Michigami, Toshimi; Hasegawa, Kosei; Kitaoka, Taichi; Kubota, Takuo; Imanishi, Yasuo; Shimotsuji, Tsunesuke; Ozono, Keiichi

2014-10-01

Hypophosphatemia and increased serum fibroblast growth factor 23 (FGF23) levels have been reported in young brothers with compound heterozygous mutations for the FAM20C gene; however, rickets was not observed in these cases. We report an adult case of Raine syndrome accompanying hypophosphatemic osteomalacia with a homozygous FAM20C mutation (R408W) associated with increased periosteal bone formation in the long bones and an increase in bone mineral density in the femoral neck. The patient, a 61-year-old man, was born from a cousin-to-cousin marriage. A short stature and severe dental demineralization were reported at an elementary school age. Hypophosphatemia was noted inadvertently at 27years old, at which time he started to take an active vitamin D metabolite (alphacalcidol) and phosphate. He also manifested ossification of the posterior longitudinal ligament. On bone biopsy performed at the age of 41years, we found severe osteomalacia surrounding osteocytes, which appeared to be an advanced form of periosteocytic hypomineralized lesions compared to those reported in patients with X-linked hypophosphatemic rickets. Laboratory data at 61years of age revealed markedly increased serum intact-FGF23 levels, which were likely to be the cause of hypophosphatemia and the decreased level of 1,25(OH)2D. We recently identified a homozygous FAM20C mutation, which was R408W, in this patient. When expressed in HEK293 cells, the R408W mutant protein exhibited impaired kinase activity and secretion. Our findings suggest that certain homozygous FAM20C mutations can cause FGF23-related hypophosphatemic osteomalacia and indicate the multiple roles of FAM20C in bone. Copyright © 2014 Elsevier Inc. All rights reserved.

Novel homozygous mutation, c.400C>T (p.Arg134*), in the PVRL1 gene underlies cleft lip/palate-ectodermal dysplasia syndrome in an Asian patient.

Science.gov (United States)

Yoshida, Kazue; Hayashi, Ryota; Fujita, Hideki; Kubota, Masaya; Kondo, Mai; Shimomura, Yutaka; Niizeki, Hironori

2015-07-01

Cleft lip/palate-ectodermal dysplasia syndrome is a rare, autosomal recessive disorder caused by homozygous loss-of-function mutations of the poliovirus receptor-like 1 (PVRL1) gene encoding nectin-1. Nectin-1 is a cell-cell adhesion molecule that is important for the initial step in the formation of adherens junctions and tight junctions; it is expressed in keratinocytes, neurons, and the developing face and palate. Clinical manifestations comprise a unique facial appearance with cleft lip/palate, ectodermal dysplasia, cutaneous syndactyly of the fingers and/or toes, and in some cases, mental retardation. We present the first report, to our knowledge, of an Asian individual with cleft lip/palate-ectodermal dysplasia syndrome with a novel PVRL1 mutation. A 7-year-old Japanese boy, the first child of a consanguineous marriage, showed hypohidrotic ectodermal dysplasia with sparse, brittle, fine, dry hair and hypodontia, the unique facial appearance with cleft lip/palate, cutaneous syndactyly of the fingers and mild mental retardation. Scanning electron microscopic examination of the hair demonstrated pili torti and pili trianguli et canaliculi. Mutation analysis of exon 2 of PVRL1 revealed a novel homozygous nonsense mutation, c.400C>T (p.Arg134*). His parents were heterozygous for the mutant alleles. All four PVRL1 mutations identified in cleft lip/palate-ectodermal dysplasia syndrome to date, including this study, resulted in truncated proteins that lack the transmembrane domain and intracellular domain of nectin-1, which is necessary to initiate the cell-cell adhesion process. © 2015 Japanese Dermatological Association.

Impact of kinase activating and inactivating patient mutations on binary PKA interactions.

Science.gov (United States)

Röck, Ruth; Mayrhofer, Johanna E; Bachmann, Verena; Stefan, Eduard

2015-01-01

The second messenger molecule cAMP links extracellular signals to intracellular responses. The main cellular cAMP effector is the compartmentalized protein kinase A (PKA). Upon receptor initiated cAMP-mobilization, PKA regulatory subunits (R) bind cAMP thereby triggering dissociation and activation of bound PKA catalytic subunits (PKAc). Mutations in PKAc or RIa subunits manipulate PKA dynamics and activities which contribute to specific disease patterns. Mutations activating cAMP/PKA signaling contribute to carcinogenesis or hormone excess, while inactivating mutations cause hormone deficiency or resistance. Here we extended the application spectrum of a Protein-fragment Complementation Assay based on the Renilla Luciferase to determine binary protein:protein interactions (PPIs) of the PKA network. We compared time- and dose-dependent influences of cAMP-elevation on mutually exclusive PPIs of PKAc with the phosphotransferase inhibiting RIIb and RIa subunits and the protein kinase inhibitor peptide (PKI). We analyzed PKA dynamics following integration of patient mutations into PKAc and RIa. We observed that oncogenic modifications of PKAc(L206R) and RIa(Δ184-236) as well as rare disease mutations in RIa(R368X) affect complex formation of PKA and its responsiveness to cAMP elevation. With the cell-based PKA PPI reporter platform we precisely quantified the mechanistic details how inhibitory PKA interactions and defined patient mutations contribute to PKA functions.

A homozygous MYO7A mutation associated to Usher syndrome and unilateral auditory neuropathy spectrum disorder.

Science.gov (United States)

Xia, Hong; Hu, Pengzhi; Yuan, Lamei; Xiong, Wei; Xu, Hongbo; Yi, Junhui; Yang, Zhijian; Deng, Xiong; Guo, Yi; Deng, Hao

2017-10-01

Usher syndrome (USH) is an autosomal recessive disorder characterized by sensorineural hearing loss, progressive visual loss and night blindness due to retinitis pigmentosa (RP), with or without vestibular dysfunction. The purpose of this study was to detect the causative gene in a consanguineous Chinese family with USH. A c.3696_3706del (p.R1232Sfs*72) variant in the myosin VIIa gene (MYO7A) was identified in the homozygous state by exome sequencing. The co‑segregation of the MYO7A c.3696_3706del variant with the phenotype of deafness and progressive visual loss in the USH family was confirmed by Sanger sequencing. The variant was absent in 200 healthy controls. Therefore, the c.3696_3706del variant may disrupt the interaction between myosin VIIa and other USH1 proteins, and impair melanosome transport in retinal pigment epithelial cells. Notably, bilateral auditory brainstem responses were absent in two patients of the USH family, while distortion product otoacoustic emissions were elicited in the right ears of the two patients, consistent with clinical diagnosis of unilateral auditory neuropathy spectrum disorder. These data suggested that the homozygous c.3696_3706del variant in the MYO7A gene may be the disease‑causing mutation for the disorder in this family. These findings broaden the phenotype spectrum of the MYO7A gene, and may facilitate understanding of the molecular pathogenesis of the disease, and genetic counseling for the family.

Inactivating mutations in ESCO2 cause SC phocomelia and Roberts syndrome: no phenotype-genotype correlation.

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Schüle, Birgitt; Oviedo, Angelica; Johnston, Kathreen; Pai, Shashidhar; Francke, Uta

2005-12-01

The rare, autosomal recessive Roberts syndrome (RBS) is characterized by tetraphocomelia, profound growth deficiency of prenatal onset, craniofacial anomalies, microcephaly, and mental deficiency. SC phocomelia (SC) has a milder phenotype, with a lesser degree of limb reduction and with survival to adulthood. Since heterochromatin repulsion (HR) is characteristic for both disorders and is not complemented in somatic-cell hybrids, it has been hypothesized that the disorders are allelic. Recently, mutations in ESCO2 (establishment of cohesion 1 homolog 2) on 8p21.1 have been reported in RBS. To determine whether ESCO2 mutations are also responsible for SC, we studied three families with SC and two families in which variable degrees of limb and craniofacial abnormalities, detected by fetal ultrasound, led to pregnancy terminations. All cases were positive for HR. We identified seven novel mutations in exons 3-8 of ESCO2. In two families, affected individuals were homozygous--for a 5-nucleotide deletion in one family and a splice-site mutation in the other. In three nonconsanguineous families, probands were compound heterozygous for a single-nucleotide insertion or deletion, a nonsense mutation, or a splice-site mutation. Abnormal splice products were characterized at the RNA level. Since only protein-truncating mutations were identified, regardless of clinical severity, we conclude that genotype does not predict phenotype. Having established that RBS and SC are caused by mutations in the same gene, we delineated the clinical phenotype of the tetraphocomelia spectrum that is associated with HR and ESCO2 mutations and differentiated it from other types of phocomelia that are negative for HR.

Forecasting the Long-Term Clinical and Economic Outcomes of Lumacaftor/Ivacaftor in Cystic Fibrosis Patients with Homozygous phe508del Mutation.

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Dilokthornsakul, Piyameth; Patidar, Mausam; Campbell, Jonathan D

2017-12-01

To forecast lifetime outcomes and cost of lumacaftor/ivacaftor combination therapy in patients with cystic fibrosis (CF) with homozygous phe508del mutation from the US payer perspective. A lifetime Markov model was developed from a US payer perspective. The model included five health states: 1) mild lung disease (percent predicted forced expiratory volume in 1 second [FEV 1 ] >70%), 2) moderate lung disease (40% ≤ FEV 1 ≤ 70%), 3) severe lung disease (FEV 1 < 40%), 4) lung transplantation, and 5) death. All inputs were derived from published literature. We estimated lumacaftor/ivacaftor's improvement in outcomes compared with a non-CF referent population as well as CF-specific mortality estimates. Lumacaftor/ivacaftor was associated with additional 2.91 life-years (95% credible interval 2.55-3.56) and additional 2.42 quality-adjusted life-years (QALYs) (95% credible interval 2.10-2.98). Lumacaftor/ivacaftor was associated with improvements in survival and QALYs equivalent to 27.6% and 20.7%, respectively, for the survival and QALY gaps between CF usual care and their non-CF peers. The incremental lifetime cost was $2,632,249. Lumacaftor/ivacaftor increased life-years and QALYs in CF patients with the homozygous phe508del mutation and moved morbidity and mortality closer to that of their non-CF peers but it came with higher cost. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

High proportion of genetic cases in patients with advanced cardiomyopathy including a novel homozygous Plakophilin 2-gene mutation.

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Baerbel Klauke

Full Text Available Cardiomyopathies might lead to end-stage heart disease with the requirement of drastic treatments like bridging up to transplant or heart transplantation. A not precisely known proportion of these diseases are genetically determined. We genotyped 43 index-patients (30 DCM, 10 ARVC, 3 RCM with advanced or end stage cardiomyopathy using a gene panel which covered 46 known cardiomyopathy disease genes. Fifty-three variants with possible impact on disease in 33 patients were identified. Of these 27 (51% were classified as likely pathogenic or pathogenic in the MYH7, MYL2, MYL3, NEXN, TNNC1, TNNI3, DES, LMNA, PKP2, PLN, RBM20, TTN, and CRYAB genes. Fifty-six percent (n = 24 of index-patients carried a likely pathogenic or pathogenic mutation. Of these 75% (n = 18 were familial and 25% (n = 6 sporadic cases. However, severe cardiomyopathy seemed to be not characterized by a specific mutation profile. Remarkably, we identified a novel homozygous PKP2-missense variant in a large consanguineous family with sudden death in early childhood and several members with heart transplantation in adolescent age.

Severe early onset retinitis pigmentosa in a Moroccan patient with Heimler syndrome due to novel homozygous mutation of PEX1 gene.

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Ratbi, Ilham; Jaouad, Imane Cherkaoui; Elorch, Hamza; Al-Sheqaih, Nada; Elalloussi, Mustapha; Lyahyai, Jaber; Berraho, Amina; Newman, William G; Sefiani, Abdelaziz

2016-10-01

Heimler syndrome (HS) is a rare recessive disorder characterized by sensorineural hearing loss (SNHL), amelogenesis imperfecta, nail abnormalities, and occasional or late-onset retinal pigmentation. It is the mildest form known to date of peroxisome biogenesis disorder caused by hypomorphic mutations of PEX1 and PEX6 genes. We report on a second Moroccan family with Heimler syndrome with early onset, severe visual impairment and important phenotypic overlap with Usher syndrome. The patient carried a novel homozygous missense variant c.3140T > C (p.Leu1047Pro) of PEX1 gene. As standard biochemical screening of blood for evidence of a peroxisomal disorder did not provide a diagnosis in the individuals with HS, patients with SNHL and retinal pigmentation should have mutation analysis of PEX1 and PEX6 genes. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Pregnancy-associated osteoporosis with a heterozygous deactivating LDL receptor-related protein 5 (LRP5) mutation and a homozygous methylenetetrahydrofolate reductase (MTHFR) polymorphism.

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Cook, Fiona J; Mumm, Steven; Whyte, Michael P; Wenkert, Deborah

2014-04-01

Pregnancy-associated osteoporosis (PAO) is a rare, idiopathic disorder that usually presents with vertebral compression fractures (VCFs) within 6 months of a first pregnancy and delivery. Spontaneous improvement is typical. There is no known genetic basis for PAO. A 26-year-old primagravida with a neonatal history of unilateral blindness attributable to hyperplastic primary vitreous sustained postpartum VCFs consistent with PAO. Her low bone mineral density (BMD) seemed to respond to vitamin D and calcium therapy, with no fractures after her next successful pregnancy. Investigation of subsequent fetal losses revealed homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism associated both with fetal loss and with osteoporosis (OP). Because her neonatal unilateral blindness and OP were suggestive of loss-of-function mutation(s) in the gene that encodes LDL receptor-related protein 5 (LRP5), LRP5 exon and splice site sequencing was also performed. This revealed a unique heterozygous 12-bp deletion in exon 21 (c.4454_4465del, p.1485_1488del SSSS) in the patient, her mother and sons, but not her father or brother. Her mother had a normal BMD, no history of fractures, PAO, ophthalmopathy, or fetal loss. Her two sons had no ophthalmopathy and no skeletal issues. Her osteoporotic father (with a family history of blindness) and brother had low BMDs first documented at ages ∼40 and 32 years, respectively. Serum biochemical and bone turnover studies were unremarkable in all subjects. We postulate that our patient's heterozygous LRP5 mutation together with her homozygous MTHFR polymorphism likely predisposed her to low peak BMD. However, OP did not cosegregate in her family with the LRP5 mutation, the homozygous MTHFR polymorphism, or even the combination of the two, implicating additional genetic or nongenetic factors in her PAO. Nevertheless, exploration for potential genetic contributions to PAO may explain part of the pathogenesis of this

A homozygous FITM2 mutation causes a deafness-dystonia syndrome with motor regression and signs of ichthyosis and sensory neuropathy

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Celia Zazo Seco

2017-02-01

Full Text Available A consanguineous family from Pakistan was ascertained to have a novel deafness-dystonia syndrome with motor regression, ichthyosis-like features and signs of sensory neuropathy. By applying a combined strategy of linkage analysis and whole-exome sequencing in the presented family, a homozygous nonsense mutation, c.4G>T (p.Glu2*, in FITM2 was identified. FITM2 and its paralog FITM1 constitute an evolutionary conserved protein family involved in partitioning of triglycerides into cellular lipid droplets. Despite the role of FITM2 in neutral lipid storage and metabolism, no indications for lipodystrophy were observed in the affected individuals. In order to obtain independent evidence for the involvement of FITM2 in the human pathology, downregulation of the single Fitm ortholog, CG10671, in Drosophila melanogaster was pursued using RNA interference. Characteristics of the syndrome, including progressive locomotor impairment, hearing loss and disturbed sensory functions, were recapitulated in Drosophila, which supports the causative nature of the FITM2 mutation. Mutation-based genetic counseling can now be provided to the family and insight is obtained into the potential impact of genetic variation in FITM2.

Bimodal voltage dependence of TRPA1: mutations of a key pore helix residue reveal strong intrinsic voltage-dependent inactivation.

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Wan, Xia; Lu, Yungang; Chen, Xueqin; Xiong, Jian; Zhou, Yuanda; Li, Ping; Xia, Bingqing; Li, Min; Zhu, Michael X; Gao, Zhaobing

2014-07-01

Transient receptor potential A1 (TRPA1) is implicated in somatosensory processing and pathological pain sensation. Although not strictly voltage-gated, ionic currents of TRPA1 typically rectify outwardly, indicating channel activation at depolarized membrane potentials. However, some reports also showed TRPA1 inactivation at high positive potentials, implicating voltage-dependent inactivation. Here we report a conserved leucine residue, L906, in the putative pore helix, which strongly impacts the voltage dependency of TRPA1. Mutation of the leucine to cysteine (L906C) converted the channel from outward to inward rectification independent of divalent cations and irrespective to stimulation by allyl isothiocyanate. The mutant, but not the wild-type channel, displayed exclusively voltage-dependent inactivation at positive potentials. The L906C mutation also exhibited reduced sensitivity to inhibition by TRPA1 blockers, HC030031 and ruthenium red. Further mutagenesis of the leucine to all natural amino acids individually revealed that most substitutions at L906 (15/19) resulted in inward rectification, with exceptions of three amino acids that dramatically reduced channel activity and one, methionine, which mimicked the wild-type channel. Our data are plausibly explained by a bimodal gating model involving both voltage-dependent activation and inactivation of TRPA1. We propose that the key pore helix residue, L906, plays an essential role in responding to the voltage-dependent gating.

A homozygous mutation in the endothelin-3 gene associated with a combined Waardenburg type 2 and Hirschsprung phenotype (Shah-Waardenburg syndrome).

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Hofstra, R M; Osinga, J; Tan-Sindhunata, G; Wu, Y; Kamsteeg, E J; Stulp, R P; van Ravenswaaij-Arts, C; Majoor-Krakauer, D; Angrist, M; Chakravarti, A; Meijers, C; Buys, C H

1996-04-01

Hirschsprung disease (HSCR) or colonic aganglionosis is a congenital disorder characterized by an absence of intramural ganglia along variable lengths of the colon resulting in intestinal obstruction. The incidence of HSCR is 1 in 5,000 live births. Mutations in the RET gene, which codes for a receptor tyrosine kinase, and in EDNRB which codes for the endothelin-B receptor, have been shown to be associated with HSCR in humans. The lethal-spotted mouse which has pigment abnormalities, but also colonic aganglionosis, carries a mutation in the gene coding for endothelin 3 (Edn3), the ligand for the receptor protein encoded by EDNRB. Here, we describe a mutation of the human gene for endothelin 3 (EDN3), homozygously present in a patient with a combined Waardenburg syndrome type 2 (WS2) and HSCR phenotype (Shah-Waardenburg syndrome). The mutation, Cys159Phe, in exon 3 in the ET-3 like domain of EDN3, presumably affects the proteolytic processing of the preproendothelin to the mature peptide EDN3. The patient's parents were first cousins. A previous child in this family had been diagnosed with a similar combination of HSCR, depigmentation and deafness. Depigmentation and deafness were present in other relatives. Moreover, we present a further indication for the involvement of EDNRB in HSCR by reporting a novel mutation detected in one of 40 unselected HSCR patients.

The phenotype of polycythemia due to Croatian homozygous VHL (571C>G:H191D) mutation is different from that of Chuvash polycythemia (VHL 598C>T:R200W).

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Tomasic, Nikica Ljubas; Piterkova, Lucie; Huff, Chad; Bilic, Ernest; Yoon, Donghoon; Miasnikova, Galina Y; Sergueeva, Adelina I; Niu, Xiaomei; Nekhai, Sergei; Gordeuk, Victor; Prchal, Josef T

2013-04-01

Mutations of VHL (a negative regulator of hypoxia-inducible factors) have position-dependent distinct cancer phenotypes. Only two known inherited homozygous VHL mutations exist and they cause polycythemia: Chuvash R200W and Croatian H191D. We report a second polycythemic Croatian H191D homozygote distantly related to the first propositus. Three generations of both families were genotyped for analysis of shared ancestry. Biochemical and molecular tests were performed to better define their phenotypes, with an emphasis on a comparison with Chuvash polycythemia. The VHL H191D mutation did not segregate in the family defined by the known common ancestors of the two subjects, suggesting a high prevalence in Croatians, but haplotype analysis indicated an undocumented common ancestor ∼six generations ago as the founder of this mutation. We show that erythropoietin levels in homozygous VHL H191D individuals are higher than in VHL R200W patients of similar ages, and their native erythroid progenitors, unlike Chuvash R200W, are not hypersensitive to erythropoietin. This observation contrasts with a report suggesting that polycythemia in VHL R200W and H191D homozygotes is due to the loss of JAK2 regulation from VHL R200W and H191D binding to SOCS1. In conclusion, our studies further define the hematologic phenotype of VHL H191D and provide additional evidence for phenotypic heterogeneity associated with the positional effects of VHL mutations.

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

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

2013-01-01

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

Normosmic idiopathic hypogonadotropic hypogonadism due to a novel homozygous nonsense c.C969A (p.Y323X) mutation in the KISS1R gene in three unrelated families.

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Demirbilek, Huseyin; Ozbek, M Nuri; Demir, Korcan; Kotan, L Damla; Cesur, Yasar; Dogan, Murat; Temiz, Fatih; Mengen, Eda; Gurbuz, Fatih; Yuksel, Bilgin; Topaloglu, A Kemal

2015-03-01

The spectrum of genetic alterations in cases of hypogonadotropic hypogonadism continue to expand. However, KISS1R mutations remain rare. The aim of this study was to understand the molecular basis of normosmic idiopathic hypogonadotropic hypogonadism. Clinical characteristics, hormonal studies and genetic analyses of seven cases with idiopathic normosmic hypogonadotropic hypogonadism (nIHH) from three unrelated consanguineous families are presented. One male presented with absence of pubertal onset and required surgery for severe penoscrotal hypospadias and cryptorchidism, while other two males had absence of pubertal onset. Two of four female cases required replacement therapy for pubertal onset and maintenance, whereas the other two had spontaneous pubertal onset but incomplete maturation. In sequence analysis, we identified a novel homozygous nonsense (p.Y323X) mutation (c.C969A) in the last exon of the KISS1R gene in all clinically affected cases. We identified a homozygous nonsense mutation in the KISS1R gene in three unrelated families with nIHH, which enabled us to observe the phenotypic consequences of this rare condition. Escape from nonsense-mediated decay, and thus production of abnormal proteins, may account for the variable severity of the phenotype. Although KISS1R mutations are extremely rare and can cause a heterogeneous phenotype, analysis of the KISS1R gene should be a part of genetic analysis of patients with nIHH, to allow better understanding of phenotype-genotype relationship of KISS1R mutations and the underlying genetic basis of patients with nIHH. © 2014 John Wiley & Sons Ltd.

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

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Hiroshi Kawakami

2014-10-01

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

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

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Kawakami, Hiroshi; Uchiyama, Masaki; Maeda, Tatsuo; Tsunoda, Takahiko; Mitsuhashi, Yoshihiko; Tsuboi, Ryoji

2014-09-01

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

Homozygous PMS2 deletion causes a severe colorectal cancer and multiple adenoma phenotype without extraintestinal cancer.

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Will, Olivia; Carvajal-Carmona, Luis G; Gorman, Patricia; Howarth, Kimberley M; Jones, Angela M; Polanco-Echeverry, Guadalupe M; Chinaleong, Jo-Anne; Günther, Thomas; Silver, Andrew; Clark, Susan K; Tomlinson, Ian

2007-02-01

We report a patient of Indian descent with parental consanguinity, who developed 10 carcinomas and 35 adenomatous polyps at age 23 and duodenal adenocarcinoma at age 25. He also had dysmorphic features, mental retardation, and café-au-lait spots but no brain tumor. We aimed to establish his molecular diagnosis. Germ-line screening for APC and MYH/MUTYH mutations was normal as was immunohistochemistry for MLH1 and MSH2 proteins. Investigation by array-comparative genomic hybridization revealed deletion of a small region on chromosome 7. Using polymerase chain reaction, this region was refined to a 400-kilobase deletion, which included exons 9-15 of the PMS2 gene, and all coding regions of oncomodulin, TRIAD3, and FSCN1. The deletion was confirmed as homozygous, and both parents were carriers. Immunohistochemistry showed absent PMS2 expression in all tumors and normal tissue. Most tumors showed microsatellite instability, more marked at dinucleotide than mononucleotide repeats. The tumors harbored no somatic mutations in APC, BRAF, AXIN2, or beta-catenin, but KRAS2 and TGFBR2 mutations were found. Our patient represents a novel phenotype for homozygous PMS2 mutation and perhaps the most severe colorectal cancer phenotype-in terms of numbers of malignancies at an early age-described to date. PMS2 mutations-and perhaps other homozygous mismatch repair mutations-should be considered in any patient presenting with multiple gastrointestinal tumors, since our patient could not be distinguished clinically from cases with attenuated familial adenomatous polyposis or MUTYH-associated polyposis.

A novel homozygous mutation IVS6+5G>T in CYP11B1 gene in a Vietnamese patient with 11β-hydroxylase deficiency.

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Nguyen, Thi Phuong Mai; Nguyen, Thu Hien; Ngo, Diem Ngoc; Vu, Chi Dung; Nguyen, Thi Kim Lien; Nong, Van Hai; Nguyen, Huy Hoang

2015-07-10

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease which is characterized by a deficiency of one of the enzymes involved in the synthesis of cortisol from cholesterol by the adrenal cortex. CAH cases arising from impaired 11β-hydroxylase are the second most common form. Mutations in the CYP11B1 gene are the cause of 11β-hydroxylase deficiency. This study was performed on a patient with congenital adrenal hyperplasia and with premature development such as enlarged penis, muscle development, high blood pressure, and bone age equivalent of 5 years old at 2 years of chronological age. Biochemical tests for steroids confirmed the diagnosis of CAH. We used PCR and sequencing to screen for mutations in CYP11B1 gene. Results showed that the patient has a novel homozygous mutation of guanine (G) to thymine (T) in intron 6 (IVS6+5G>T). The analysis of this mutation by MaxEntScan boundary software indicated that this mutant could affect the gene splicing during transcription. Copyright © 2015 Elsevier B.V. All rights reserved.

Depolarized inactivation overcomes impaired activation to produce DRG neuron hyperexcitability in a Nav1.7 mutation in a patient with distal limb pain.

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Huang, Jianying; Yang, Yang; Dib-Hajj, Sulayman D; van Es, Michael; Zhao, Peng; Salomon, Jody; Drenth, Joost P H; Waxman, Stephen G

2014-09-10

Sodium channel Nav1.7, encoded by SCN9A, is expressed in DRG neurons and regulates their excitability. Genetic and functional studies have established a critical contribution of Nav1.7 to human pain disorders. We have now characterized a novel Nav1.7 mutation (R1279P) from a female human subject with distal limb pain, in which depolarized fast inactivation overrides impaired activation to produce hyperexcitability and spontaneous firing in DRG neurons. Whole-cell voltage-clamp recordings in human embryonic kidney (HEK) 293 cells demonstrated that R1279P significantly depolarizes steady-state fast-, slow-, and closed-state inactivation. It accelerates deactivation, decelerates inactivation, and facilitates repriming. The mutation increases ramp currents in response to slow depolarizations. Our voltage-clamp analysis showed that R1279P depolarizes channel activation, a change that was supported by our multistate structural modeling. Because this mutation confers both gain-of-function and loss-of-function attributes on the Nav1.7 channel, we tested the impact of R1279P expression on DRG neuron excitability. Current-clamp studies reveal that R1279P depolarizes resting membrane potential, decreases current threshold, and increases firing frequency of evoked action potentials within small DRG neurons. The populations of spontaneously firing and repetitively firing neurons were increased by expressing R1279P. These observations indicate that the dominant proexcitatory gating changes associated with this mutation, including depolarized steady-state fast-, slow-, and closed-state inactivation, faster repriming, and larger ramp currents, override the depolarizing shift of activation, to produce hyperexcitability and spontaneous firing of nociceptive neurons that underlie pain. Copyright © 2014 the authors 0270-6474/14/3412328-13$15.00/0.

A Homozygous Missense Mutation in TGM5 Abolishes Epidermal Transglutaminase 5 Activity and Causes Acral Peeling Skin Syndrome

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Cassidy, Andrew J.; van Steensel, Maurice A. M.; Steijlen, Peter M.; van Geel, Michel; Velden, Jaap van der; Morley, Susan M.; Terrinoni, Alessandro; Melino, Gerry; Candi, Eleonora; McLean, W. H. Irwin

2005-01-01

Peeling skin syndrome is an autosomal recessive genodermatosis characterized by the shedding of the outer epidermis. In the acral form, the dorsa of the hands and feet are predominantly affected. Ultrastructural analysis has revealed tissue separation at the junction between the granular cells and the stratum corneum in the outer epidermis. Genomewide linkage analysis in a consanguineous Dutch kindred mapped the gene to 15q15.2 in the interval between markers D15S1040 and D15S1016. Two homozygous missense mutations, T109M and G113C, were found in TGM5, which encodes transglutaminase 5 (TG5), in all affected persons in two unrelated families. The mutation was present on the same haplotype in both kindreds, indicating a probable ancestral mutation. TG5 is strongly expressed in the epidermal granular cells, where it cross-links a variety of structural proteins in the terminal differentiation of the epidermis to form the cornified cell envelope. An established, in vitro, biochemical cross-linking assay revealed that, although T109M is not pathogenic, G113C completely abolishes TG5 activity. Three-dimensional modeling of TG5 showed that G113C lies close to the catalytic domain, and, furthermore, that this glycine residue is conserved in all known transglutaminases, which is consistent with pathogenicity. Other families with more-widespread peeling skin phenotypes lacked TGM5 mutations. This study identifies the first causative gene in this heterogeneous group of skin disorders and demonstrates that the protein cross-linking function performed by TG5 is vital for maintaining cell-cell adhesion between the outermost layers of the epidermis. PMID:16380904

Phenotypical features of two patients diagnosed with PHARC syndrome and carriers of a new homozygous mutation in the ABHD12 gene.

Science.gov (United States)

Frasquet, Marina; Lupo, Vincenzo; Chumillas, María José; Vázquez-Costa, Juan Francisco; Espinós, Carmen; Sevilla, Teresa

2018-04-15

PHARC (Polyneuropathy, Hearing loss, Ataxia, Retinitis pigmentosa and Cataracts) (MIM# 612674) is an autosomal recessive neurodegenerative disease caused by mutations in the ABHD12 gene. We evaluated two Spanish siblings affected with pes cavus, sensorimotor neuropathy, hearing loss, retinitis pigmentosa and juvenile cataracts in whom the genetic test of ABHD12 revealed a novel homozygous frameshift mutation, c.211_223del (p.Arg71Tyrfs*26). The earliest clinical manifestation in these patients was a demyelinating neuropathy manifested with a Charcot-Marie-Tooth phenotype over three decades. Progressive hearing loss, cataracts and retinitis pigmentosa appeared after the age of 30. We herein describe the complete clinical picture of these two patients, and focus particularly on neuropathy characteristics. This study supports the fact that although PHARC is rare, its phenotype is very characteristic and we should include its study in patients affected with demyelinating polyneuropathy, hearing loss and retinopathy. Copyright © 2018 Elsevier B.V. All rights reserved.

A novel homozygous variant in the SMOC1 gene underlying Waardenburg anophthalmia syndrome.

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Ullah, Asmat; Umair, Muhammad; Ahmad, Farooq; Muhammad, Dost; Basit, Sulman; Ahmad, Wasim

2017-01-01

Waardenburg anophthalmia syndrome (WAS), also known as ophthalmo-acromelic syndrome or anophthalmia-syndactyly, is a rare congenital disorder that segregates in an autosomal recessive pattern. Clinical features of the syndrome include malformation of the eyes and the skeleton. Mostly, WAS is caused by mutations in the SMOC-1 gene. The present report describes a large consanguineous family of Pakistani origin segregating Waardenburg anophthalmia syndrome in an autosomal recessive pattern. Genotyping followed by Sanger sequencing was performed to search for a candidate gene. SNP genotyping using AffymetrixGeneChip Human Mapping 250K Nsp array established a single homozygous region among affected members on chromosome 14q23.1-q24.3 harboring the SMOC1 gene. Sequencing of the gene revealed a novel homozygous missense mutation (c.812G>A; p.Cys271Tyr) in the family. This is the first report of Waardenburg anophthalmia syndrome caused by a SMOC1 variant in a Pakistani population. The mutation identified in the present investigation extends the body of evidence implicating the gene SMOC-1 in causing WAS.

Comprehensive genomic profiling reveals inactivating SMARCA4 mutations and low tumor mutational burden in small cell carcinoma of the ovary, hypercalcemic-type.

Science.gov (United States)

Lin, Douglas I; Chudnovsky, Yakov; Duggan, Bridget; Zajchowski, Deborah; Greenbowe, Joel; Ross, Jeffrey S; Gay, Laurie M; Ali, Siraj M; Elvin, Julia A

2017-12-01

Small cell carcinoma of the ovary, hypercalcemic-type (SCCOHT) is a rare, extremely aggressive neoplasm that usually occurs in young women and is characterized by deleterious germline or somatic SMARCA4 mutations. We performed comprehensive genomic profiling (CGP) to potentially identify additional clinically and pathophysiologically relevant genomic alterations in SCCOHT. CGP assessment of all classes of coding alterations in up to 406 genes commonly altered in cancer and intronic regions for up to 31 genes commonly rearranged in cancer was performed on 18 SCCOHT cases (16 exhibiting classic morphology and 2 cases exhibiting exclusive a large cell variant morphology). In addition, a retrospective database search for clinically advanced ovarian tumors with genomic profiles similar to SCCOHT yielded 3 additional cases originally diagnosed as non-SCCOHT. CGP revealed inactivating SMARCA4 alterations and low tumor mutational burden (TMB) (<6mutations/Mb) in 94% (15/16) of SCCOHT with classic morphology. In contrast, both (2/2) cases exhibiting only large cell variant morphology were hypermutated (TMB scores of 90 and 360mut/Mb) and were wildtype for SMARCA4. In our retrospective search, an index ovarian cancer patient harboring inactivating SMARCA4 alterations, initially diagnosed as endometrioid carcinoma, was re-classified as SCCOHT and responded to an SCCOHT chemotherapy regimen. The vast majority of SCCOHT demonstrate genomic SMARCA4 loss with only rare co-occurring alterations. Our data support a role for CGP in the diagnosis and management of SCCOHT and of other lesions with overlapping histological and clinical features, since identifying the former by genomic profile suggests benefit from an appropriate regimen and treatment decisions, as illustrated by an index patient. Copyright © 2017 Elsevier Inc. All rights reserved.

Germ-line mutations of the p53 tumor suppressor gene in patients with high risk for cancer inactivate the p53 protein.

Science.gov (United States)

Frebourg, T; Kassel, J; Lam, K T; Gryka, M A; Barbier, N; Andersen, T I; Børresen, A L; Friend, S H

1992-07-15

Germ-line mutations in the p53 tumor suppressor gene have been observed in patients with Li-Fraumeni syndrome, brain tumors, second malignancies, and breast cancers. It is unclear whether all of these mutations have inactivated p53 and thereby provide an increased risk for cancer. Therefore, it is necessary to establish the biological significance of these germ-line mutations by the functional and structural analysis of the resulting mutant p53 proteins. We analyzed the ability of seven germ-line mutant proteins observed in patients with Li-Fraumeni syndrome, second primary neoplasms, or familial breast cancer to block the growth of malignant cells and compared the structural properties of the mutant proteins to that of the wild-type protein. Six of seven missense mutations disrupted the growth inhibitory properties and structure of the wild-type protein. One germ-line mutation retained the features of the wild-type p53. Genetic analysis of the breast cancer family in which this mutation was observed indicated that this germ-line mutation was not associated with the development of cancer. These results demonstrate that germ-line p53 mutations observed in patients with Li-Fraumeni syndrome and with second malignancies have inactivated the p53 tumor suppressor gene. The inability of the germ-line p53 mutants to block the growth of malignant cells can explain why patients with these germ-line mutations have an increased risk for cancer. The observation of a functionally silent germ-line mutation indicates that, before associating a germ-line tumor suppressor gene mutation with cancer risk, it is prudent to consider its functional significance.

Germ-line mutations of the p53 tumor suppressor gene in patients with high risk for cancer inactivate the p53 protein.

Science.gov (United States)

Frebourg, T; Kassel, J; Lam, K T; Gryka, M A; Barbier, N; Andersen, T I; Børresen, A L; Friend, S H

1992-01-01

Germ-line mutations in the p53 tumor suppressor gene have been observed in patients with Li-Fraumeni syndrome, brain tumors, second malignancies, and breast cancers. It is unclear whether all of these mutations have inactivated p53 and thereby provide an increased risk for cancer. Therefore, it is necessary to establish the biological significance of these germ-line mutations by the functional and structural analysis of the resulting mutant p53 proteins. We analyzed the ability of seven germ-line mutant proteins observed in patients with Li-Fraumeni syndrome, second primary neoplasms, or familial breast cancer to block the growth of malignant cells and compared the structural properties of the mutant proteins to that of the wild-type protein. Six of seven missense mutations disrupted the growth inhibitory properties and structure of the wild-type protein. One germ-line mutation retained the features of the wild-type p53. Genetic analysis of the breast cancer family in which this mutation was observed indicated that this germ-line mutation was not associated with the development of cancer. These results demonstrate that germ-line p53 mutations observed in patients with Li-Fraumeni syndrome and with second malignancies have inactivated the p53 tumor suppressor gene. The inability of the germ-line p53 mutants to block the growth of malignant cells can explain why patients with these germ-line mutations have an increased risk for cancer. The observation of a functionally silent germ-line mutation indicates that, before associating a germ-line tumor suppressor gene mutation with cancer risk, it is prudent to consider its functional significance. Images PMID:1631137

Progression of subtle motor signs in PINK1 mutation carriers with mild dopaminergic deficit

DEFF Research Database (Denmark)

Eggers, C; Schmidt, A; Hagenah, J

2010-01-01

While homozygous mutations in the PINK1 gene cause recessively inherited early-onset Parkinson disease (PD), heterozygous mutations have been suggested as a susceptibility factor.......While homozygous mutations in the PINK1 gene cause recessively inherited early-onset Parkinson disease (PD), heterozygous mutations have been suggested as a susceptibility factor....

A Novel Homozygous MYO7A Mutation: Case Report

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Mahsa Ahmadi

2018-05-01

Full Text Available MYO7A is an unconventional myosin that is essential for ordinary hearing and vision; mutations in the MYO7A gene result in Usher syndrome type 1B and other disorders. In this manuscript, we reported a mutation (c.4705delA in exon 35, causing the alteration of a Ser amino acid to Ala at codon 1569 (p.H2027del located within the first FERMdomain of the human protein myosin VIIA. This mutation involved in the pathogenesis of hearing loss, congenital night blindness, muscular weakness, skin problem, and difficulty in keeping balance in the 13-year-old female. After checkup the patient’s DNA was extracted from peripheral blood and amplification was performed by PCR. Sequencing method was performed for identification of the mutation. The c.4705delA mutation in exon 35 was found in the patient in heterozygosis form; this means that her mother and father were carriers. This mutation is located on the tail of the myosinVIIA protein and is associated with several disorders.

Germ-line mutations of the p53 tumor suppressor gene in patients with high risk for cancer inactivate the p53 protein.

OpenAIRE

Frebourg, T; Kassel, J; Lam, K T; Gryka, M A; Barbier, N; Andersen, T I; Børresen, A L; Friend, S H

1992-01-01

Germ-line mutations in the p53 tumor suppressor gene have been observed in patients with Li-Fraumeni syndrome, brain tumors, second malignancies, and breast cancers. It is unclear whether all of these mutations have inactivated p53 and thereby provide an increased risk for cancer. Therefore, it is necessary to establish the biological significance of these germ-line mutations by the functional and structural analysis of the resulting mutant p53 proteins. We analyzed the ability of seven germ-...

Dental phenotype in Jalili syndrome due to a c.1312 dupC homozygous mutation in the CNNM4 gene.

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Hans U Luder

Full Text Available Jalili syndrome denotes a recessively inherited combination of an eye disease (cone-rod dystrophy and a dental disorder (amelogenesis imperfecta, which is caused by mutations in the CNNM4 gene. Whereas the ophthalmic consequences of these mutations have been studied comprehensively, the dental phenotype has obtained less attention. A defective transport of magnesium ions by the photoreceptors of the retina is assumed to account for the progressive visual impairment. Since magnesium is also incorporated in the mineral of dental hard tissues, we hypothesized that magnesium concentrations in defective enamel resulting from mutations in CNNM4 would be abnormal, if a similar deficiency of magnesium transport also accounted for the amelogenesis imperfecta. Thus, a detailed analysis of the dental hard tissues was performed in two boys of Kosovan origin affected by Jalili syndrome. Retinal dystrophy of the patients was diagnosed by a comprehensive eye examination and full-field electroretinography. A mutational analysis revealed a c.1312 dupC homozygous mutation in CNNM4, a genetic defect which had already been identified in other Kosovan families and putatively results in loss-of-function of the protein. The evaluation of six primary teeth using light and scanning electron microscopy as well as energy-dispersive X-ray spectroscopy showed that dental enamel was thin and deficient in mineral, suggesting a hypoplastic/hypomineralized type of amelogenesis imperfecta. The reduced mineral density of enamel was accompanied by decreased amounts of calcium, but significantly elevated levels of magnesium. In dentin, however, a similar mineral deficiency was associated with reduced magnesium and normal calcium levels. It is concluded that the c.1312 dupC mutation of CNNM4 results in mineralization defects of both enamel and dentin, which are associated with significantly abnormal magnesium concentrations. Thus, we could not disprove the hypothesis that a

Filaggrin loss-of-function mutations, atopic dermatitis and risk of actinic keratosis

DEFF Research Database (Denmark)

Andersen, Y M F; Egeberg, A; Balslev, E

2017-01-01

BACKGROUND: Common loss-of-function mutations in filaggrin gene (FLG) represent a strong genetic risk factor for atopic dermatitis (AD). Homozygous mutation carriers typically display ichthyosis vulgaris (IV) and many have concomitant AD. Previously, homozygous, but not heterozygous, filaggrin ge...

Novel Homozygous Missense Mutation in RYR1 Leads to Severe Congenital Ptosis, Ophthalmoplegia, and Scoliosis in the Absence of Myopathy.

Science.gov (United States)

Dilaver, Nafi; Mazaheri, Neda; Maroofian, Reza; Zeighami, Jawaher; Seifi, Tahere; Zamani, Mina; Sedaghat, Alireza; Shariati, Gholam Reza; Galehdari, Hamid

2017-12-01

Ryanodine receptor 1 ( RYR1 ) is an intracellular calcium receptor primarily expressed in skeletal muscle with a role in excitation contraction. Both dominant and recessive mutations in the RYR1 gene cause a range of RYR1 -related myopathies and/or susceptibility to malignant hyperthermia (MH). Recently, an atypical manifestation of ptosis, variably presenting with ophthalmoplegia, facial paralysis, and scoliosis but without significant muscle weakness, has been reported in 9 cases from 4 families with bialleic variants in RYR1 . Two affected children from a consanguineous family with severe congenital ptosis, ophthalmoplegia, scoliosis, and distinctive long faces but without skeletal myopathy were studied. To identify the cause of the hereditary condition, DNA from the proband was subjected to whole exome sequencing (WES). WES revealed a novel homozygous missense variant in RYR1 (c.14066T>A; p.IIe4689Asn), which segregated within the family. Although the phenotype of the affected siblings in this study was similar to previously described cases, the clinical features were more severely expressed. Our findings contribute to the expansion of phenotypes related to RYR1 dysfunction. Additionally, it supports a new RYR1 -related clinical presentation without musculoskeletal involvement. It is important that individuals with RYR1 mutations are considered susceptible to MH, as 70% of the MH cases are caused by mutations in the RYR1 gene.

Odonto-onycho-dermal dysplasia in a patient homozygous for a WNT10A nonsense mutation and mild manifestations of ectodermal dysplasia in carriers of the mutation.

Science.gov (United States)

Krøigård, Anne Bruun; Clemmensen, Ole; Gjørup, Hans; Hertz, Jens Michael; Bygum, Anette

2016-03-10

Odonto-onycho-dermal dysplasia (OODD) is a rare form of ectodermal dysplasia characterized by severe oligodontia, onychodysplasia, palmoplantar hyperkeratosis, dry skin, hypotrichosis, and hyperhidrosis of the palms and soles. The ectodermal dysplasias resulting from biallelic mutations in the WNT10A gene result in highly variable phenotypes, ranging from isolated tooth agenesis to OODD and Schöpf-Schulz-Passarge syndrome (SSPS). We identified a female patient, with consanguineous parents, who was clinically diagnosed with OODD. Genetic testing showed that she was homozygous for a previously reported pathogenic mutation in the WNT10A gene, c.321C > A, p.Cys107*. The skin and nail abnormalities were for many years interpreted as psoriasis and treated accordingly. A thorough clinical examination revealed hypotrichosis and hyperhidrosis of the soles and dental examination revealed agenesis of permanent teeth except the two maxillary central incisors. Skin biopsies from the hyperkeratotic palms and soles showed the characteristic changes of eccrine syringofibroadenomatosis, which has been described in patients with ectodermal dysplasias. Together with a family history of tooth anomalies, this lead to the clinical suspicion of a hereditary ectodermal dysplasia. This case illustrates the challenges of diagnosing ectodermal dysplasia like OODD and highlights the relevance of interdisciplinary cooperation in the diagnosis of rare conditions.

Accelerated inactivation of the L-type calcium current due to a mutation in CACNB2b underlies Brugada syndrome

DEFF Research Database (Denmark)

Cordeiro, Jonathan M; Marieb, Mark; Pfeiffer, Ryan

2009-01-01

S in which loss of function is caused by accelerated inactivation of I(Ca). The proband, a 32 year old male, displayed a Type I ST segment elevation in two right precordial ECG leads following a procainamide challenge. EP study was positive with induction of polymorphic VT/VF. Interrogation of implanted ICD...... significantly faster in mutant channels between 0 and + 20 mV. Action potential voltage clamp experiments showed that total charge was reduced by almost half compared to WT. We report the first BrS mutation in CaCNB2b resulting in accelerated inactivation of L-type calcium channel current. Our results suggest...

Clinical Course of Homozygous Hemoglobin Constant Spring in Pediatric Patients.

Science.gov (United States)

Komvilaisak, Patcharee; Jetsrisuparb, Arunee; Fucharoen, Goonnapa; Komwilaisak, Ratana; Jirapradittha, Junya; Kiatchoosakun, Pakaphan

2018-04-17

Hemoglobin (Hb) Constant Spring is an alpha-globin gene variant due to a mutation of the stop codon resulting in the elongation of the encoded polypeptide from 141 to 172 amino acid residues. Patients with homozygous Hb Constant Spring are usually mildly anemic. We retrospectively describe clinical manifestations, diagnosis, laboratory investigations, treatment, and associated findings in pediatric patients with homozygous Hb Constant Spring followed-up at Srinagarind Hospital. Sixteen pediatric cases (5 males and 11 females) were diagnosed in utero (N=6) or postnatal (n=10). Eleven cases were diagnosed with homozygous Hb Constant Spring, 4 with homozygous Hb Constant Spring with heterozygous Hb E, and 1 with homozygous Hb Constant Spring with homozygous Hb E. Three cases were delivered preterm. Six patients had low birth weights. Clinical manifestations included fetal anemia in 6 cases, hepatomegaly in 1 case, hepatosplenomegaly in 2 cases, splenomegaly in 1 case. Twelve cases exhibited early neonatal jaundice, 9 of which required phototherapy. Six cases received red cell transfusions; 1 (3), >1 (3). After the first few months of life, almost all patients had mild microcytic hypochromic anemia and an increased reticulocyte count with a wide red cell distribution (RDW), but no longer required red cell transfusion. At 1 to 2 years of age, some patients still had mild microcytic hypochromic anemia and some had normocytic hypochromic anemia with Hb around 10 g/dL, increased reticulocyte count and wide RDW. Associated findings included hypothyroidism (2), congenital heart diseases (4), genitourinary abnormalities (3), gastrointestinal abnormalities (2), and developmental delay (1). Pediatric patients with homozygous Hb Constant Spring developed severe anemia in utero and up to the age of 2 to 3 months postnatal, requiring blood transfusions. Subsequently, their anemia was mild with no evidence of hepatosplenomegaly. Their Hb level was above 9 g/dL with hypochromic

CYP2R1 mutations causing vitamin D-deficiency rickets.

Science.gov (United States)

Thacher, Tom D; Levine, Michael A

2017-10-01

CYP2R1 is the principal hepatic 25-hydroxylase responsible for the hydroxylation of parent vitamin D to 25-hydroxyvitamin D [25(OH)D]. Serum concentrations of 25(OH)D reflect vitamin D status, because 25(OH)D is the major circulating metabolite of vitamin D. The 1α-hydroxylation of 25(OH)D in the kidney by CYP27B1 generates the fully active vitamin D metabolite, 1,25-dihydroxyvitamin D (1,25(OH) 2 D). The human CYP2R1 gene, located at 11p15.2, has five exons, coding for an enzyme with 501 amino acids. In Cyp2r1-/- knockout mice, serum 25(OH)D levels were reduced by more than 50% compared wild-type mice. Genetic polymorphisms of CYP2R1 account for some of the individual variability of circulating 25(OH)D values in the population. We review the evidence that inactivating mutations in CYP2R1 can lead to a novel form of vitamin D-deficiency rickets resulting from impaired 25-hydroxylation of vitamin D. We sequenced the promoter, exons and intron-exon flanking regions of the CYP2R1 gene in members of 12 Nigerian families with rickets in more than one family member. We found missense mutations (L99P and K242N) in affected members of 2 of 12 families. The L99P mutation had previously been reported as a homozygous defect in an unrelated child of Nigerian origin with rickets. In silico analyses predicted impaired CYP2R1 folding or reduced interaction with substrate vitamin D by L99P and K242N mutations, respectively. In vitro studies of the mutant CYP2R1 proteins in HEK293 cells confirmed normal expression levels but completely absent or markedly reduced 25-hydroxylase activity by the L99P and K242N mutations, respectively. Heterozygous subjects had more moderate biochemical and clinical features of vitamin D deficiency than homozygous subjects. After an oral bolus dose of 50,000 IU of vitamin D 2 or vitamin D 3 , heterozygous subjects had lower increases in serum 25(OH)D than control subjects, and homozygous subjects had minimal increases, supporting a semidominant

A Taiwanese Boy With Congenital Generalized Lipodystrophy Caused by Homozygous Ile262fs Mutation in the BSCL2 Gene

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Hsiu-Hui Huang

2010-11-01

Full Text Available Congenital generalized lipodystrophy (CGL is a rare autosomal recessive disease that is characterized by a near-complete absence of adipose tissue from birth or early infancy. Mutations in the BSCL2 gene are known to result in CGL2, a more severe phenotype than CGL1, with earlier onset, more extensive fat loss and biochemical changes, more severe intellectual impairment, and more severe cardiomyopathy. We report a 3-month-old Taiwanese boy with initial presentation of a lack of subcutaneous fat, prominent musculature, generalized eruptive xanthomas, and extreme hypertriglyceridemia. Absence of mechanical adipose tissue in the orbits and scalp was revealed by head magnetic resonance imaging. Hepatomegaly was noticed, and histological examination of a liver biopsy specimen suggested severe hepatic steatosis and periportal necrosis. However, echocardiography indicated no sign of cardiomyopathy and he showed no distinct intellectual impairment that interfered with daily life. About 1 year later, abdominal computed tomography revealed enlargement of kidneys. He had a homozygous insertion of a nucleotide, 783insG (Ile262fs mutation, in exon 7 of the BSCL2 gene. We reviewed the genotype of CGL cases from Japan, India, China and Taiwan, and found that BSCL2 is a major causative gene for CGL in Asian.

Homozygous TBC1D24 mutation in two siblings with familial infantile myoclonic epilepsy (FIME) and moderate intellectual disability.

Science.gov (United States)

Poulat, Anne-Lise; Ville, Dorothée; de Bellescize, Julitta; André-Obadia, Nathalie; Cacciagli, Pierre; Milh, Mathieu; Villard, Laurent; Lesca, Gaetan

2015-03-01

Mutations in the TBC1D24 gene were first reported in an Italian family with a unique epileptic phenotype consisting of drug-responsive, early-onset idiopathic myoclonic seizures. Patients presented with isolated bilateral or focal myoclonia, which could evolve to long-lasting attacks without loss of consciousness, with a peculiar reflex component, and were associated with generalized tonic-clonic seizures. This entity was named "familial infantile myoclonic epilepsy" (FIME). More recently, TBC1D24 mutations have been shown to cause a variable range of disorders, including epilepsy of various seizure types and severity, non-syndromic deafness, and DOORS syndrome. We report on the electro-clinical features of two brothers, born to first-cousin parents, affected with infantile-onset myoclonic epilepsy. The peculiar epileptic presentation prompted us to perform direct sequencing of the TBC1D24 gene. The patients had very early onset of focal myoclonic fits with variable topography, lasting a few minutes to several hours, without loss of consciousness, which frequently evolved to generalized myoclonus or myoclonic status. Reflex myoclonia were noticed in one patient. Neurological outcome was marked by moderate intellectual disability. Despite the high frequency of seizures, repeated EEG recordings showed normal background rhythm and rare interictal spikes and waves. We found a homozygous missense mutation, c.457G>A/p.Glu153Lys, in the two affected brothers. This observation combined with recent data from the literature, suggest that mutations in TBCD24 cause a pathological continuum, with FIME at the "benign" end and severe drug-refractory epileptic encephalopathy on the severe end. Early-onset myoclonic epilepsy with focal and generalized myoclonic seizures is a common characteristic of this continuum. Copyright © 2015 Elsevier B.V. All rights reserved.

Inactivation of promoter 1B of APC causes partial gene silencing: evidence for a significant role of the promoter in regulation and causative of familial adenomatous polyposis

DEFF Research Database (Denmark)

Rohlin, A; Engwall, Y; Fritzell, K

2011-01-01

Familial adenomatous polyposis (FAP) is caused by germline mutations in the adenomatous polyposis coli (APC) gene. Two promoters, 1A and 1B, have been recognized in APC, and 1B is thought to have a minor role in the regulation of the gene. We have identified a novel deletion encompassing half of ...... homozygous inactivation of APC allowing for alternative genetic models as basis for adenoma formation.Oncogene advance online publication, 6 June 2011; doi:10.1038/onc.2011.201....... in a panel of 20 various normal tissues examined. In FAP-related tumors, the APC germline mutation is proposed to dictate the second hit. Mutations leaving two or three out of seven 20-amino-acid repeats in the central domain of APC intact seem to be required for tumorigenesis. We examined adenomas from...... mutation carriers in Family 1 for second hits in the entire gene without any findings, however, loss of the residual expression of the deleterious allele was observed. Three major conclusions of significant importance in relation to the function of APC can be drawn from this study; (i) germline...

Homozygous EEF1A2 mutation causes dilated cardiomyopathy, failure to thrive, global developmental delay, epilepsy and early death.

Science.gov (United States)

Cao, Siqi; Smith, Laura L; Padilla-Lopez, Sergio R; Guida, Brandon S; Blume, Elizabeth; Shi, Jiahai; Morton, Sarah U; Brownstein, Catherine A; Beggs, Alan H; Kruer, Michael C; Agrawal, Pankaj B

2017-09-15

Eukaryotic elongation factor 1A (EEF1A), is encoded by two distinct isoforms, EEF1A1 and EEF1A2; whereas EEF1A1 is expressed almost ubiquitously, EEF1A2 expression is limited such that it is only detectable in skeletal muscle, heart, brain and spinal cord. Currently, the role of EEF1A2 in normal cardiac development and function is unclear. There have been several reports linking de novo dominant EEF1A2 mutations to neurological issues in humans. We report a pair of siblings carrying a homozygous missense mutation p.P333L in EEF1A2 who exhibited global developmental delay, failure to thrive, dilated cardiomyopathy and epilepsy, ultimately leading to death in early childhood. A third sibling also died of a similar presentation, but DNA was unavailable to confirm the mutation. Functional genomic analysis was performed in S. cerevisiae and zebrafish. In S. cerevisiae, there was no evidence for a dominant-negative effect. Previously identified putative de novo mutations failed to complement yeast strains lacking the EEF1A ortholog showing a major growth defect. In contrast, the introduction of the mutation seen in our family led to a milder growth defect. To evaluate its function in zebrafish, we knocked down eef1a2 expression using translation blocking and splice-site interfering morpholinos. EEF1A2-deficient zebrafish had skeletal muscle weakness, cardiac failure and small heads. Human EEF1A2 wild-type mRNA successfully rescued the morphant phenotype, but mutant RNA did not. Overall, EEF1A2 appears to be critical for normal heart function in humans, and its deficiency results in clinical abnormalities in neurologic function as well as in skeletal and cardiac muscle defects. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A molecular switch driving inactivation in the cardiac K+ channel HERG.

Directory of Open Access Journals (Sweden)

David A Köpfer

Full Text Available K(+ channels control transmembrane action potentials by gating open or closed in response to external stimuli. Inactivation gating, involving a conformational change at the K(+ selectivity filter, has recently been recognized as a major K(+ channel regulatory mechanism. In the K(+ channel hERG, inactivation controls the length of the human cardiac action potential. Mutations impairing hERG inactivation cause life-threatening cardiac arrhythmia, which also occur as undesired side effects of drugs. In this paper, we report atomistic molecular dynamics simulations, complemented by mutational and electrophysiological studies, which suggest that the selectivity filter adopts a collapsed conformation in the inactivated state of hERG. The selectivity filter is gated by an intricate hydrogen bond network around residues S620 and N629. Mutations of this hydrogen bond network are shown to cause inactivation deficiency in electrophysiological measurements. In addition, drug-related conformational changes around the central cavity and pore helix provide a functional mechanism for newly discovered hERG activators.

No evidence for functional inactivation of wild-type p53 protein by MDM2 overexpression in gastric carcinogenesis

NARCIS (Netherlands)

Blok, P.; Craanen, M. E.; Dekker, W.; Offerhaus, G. J.; Tytgat, G. N.

1998-01-01

Inactivation of wild-type p53 during gastric carcinogenesis is usually caused by mutations within exons 5-8 of the p53 gene leading to mutated, usually immunohistochemically detectable p53 proteins. However, functional inactivation of wild-type p53, mimicking mutational inactivation, may also result

Qualitative analysis of mouse specific-locus mutations: information on genetic organization, gene expression, and the chromosomal nature of induced lesions

International Nuclear Information System (INIS)

Russell, L.B.

1982-01-01

Analysis of mouse specific-locus (SL) mutations at three loci has identified over 33 distinct complementation groups - most of which are probably overlapping deficiencies - and 13 to 14 new functional units. The complementation maps that have been generated for the d-se and c regions include numerous vital functions; however, some of the genes in these regions are non-vital. At such loci, hypomorphic mutants must represent intragenic alterations, and some viable nulls could conceivably be intragenic lesions also. Analysis of SL mutations has provided information on genetic expression. Homozygous deficiencies can be completely viable or can kill at any one of a range of developmental stages. Heterozygonus deficiencies of up to 6 cM or more in genetic length have been recovered and propagated. The time of death of homozygous and the degree of inviability of heterozygous deficiencies are related more to specific content of the missing segment than to its length. Combinations of deficiencies with x-autosome translocations that inactivate the homologous region in a mosaic fashion have shown that organismic lethals are not necessarily cell lethal. The spectrum of mutations induced depends on the nature of the mutagen and the type of germ cell exposed. Radiation of spermatogonia produces intragenic as well as null mutations. Spontaneous mutations have an admixture of types not present in populations of mutations induced in germ cells, and this raises doubts concerning the accuracy of doubling-dose calculations in genetic risk estimation. The analysis of SL mutations has yielded genetic tools for the construction of detailed gene-dosage series, cis-trans comparisons, the mapping of known genes and identification of new genes, genetic rescue of various types, and the identification and isolation of DNA sequences

Identification of a point mutation in growth factor repeat C of the low density lipoprotein-receptor gene in a patient with homozygous familial hypercholesterolemia

International Nuclear Information System (INIS)

Soutar, A.K.; Knight, B.L.; Patel, D.D.

1989-01-01

The coding region of the low density lipoprotein (LDL)-receptor gene from a patient (MM) with homozygous familial hypercholesterolemia (FH) has been sequenced from six overlapping 500-base-pair amplified fragments of the cDNA from cultured skin fibroblasts. Two separate single nucleotide base changes from the normal sequence were detected. The first involved substitution of guanine for adenine in the third position of the codon for amino acid residue Cys-27 and did not affect the protein sequence. The second mutation was substitution of thymine for cytosine in the DNA for the codon for amino acid residue 664, changing the codon from CCG (proline) to CTG (leucine) and introducing a new site for the restriction enzyme PstI. MM is a true homozygote with two identical genes, and the mutation cosegregated with clinically diagnosed FH in his family in which first cousin marriages occurred frequently. LDL receptors in MM's skin fibroblasts bind less LDL than normal and with reduced affinity. Thus this naturally occurring single point mutation affects both intracellular transport of the protein and ligand binding and occurs in growth factor-like repeat C, a region that has not previously been found to influence LDL binding

Physical mapping of chromosome 8p22 markers and their homozygous deletion in a metastatic prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Bova, G.S.; Pin, S.S.; Isaacs, W.B. [Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States)]|[Brady Urological Institute, Baltimore, MD (United States)] [and others

1996-07-01

Numerous studies have implicated the short arm of chromosome 8 as the site of one or more tumor suppressor genes inactivated in carcinogenesis of the prostate, colon, lung, and liver. Previously, we identified a homozygous deletion on chromosome 8p22 in a metastatic prostate cancer. To map this homozygous deletion physically, long-range restriction mapping was performed using yeast artificial chromosomes (YACs) spanning approximately 2 Mb of chromosome band 8p22. Subcloned genomic DNA and cDNA probes isolated by hybrid capture from these YACs were mapped in relation to one another, reinforcing map integrity. Mapped single-copy probes from the region were then applied to DNA isolated from a metastatic prostate cancer containing a chromosome 8p22 homozygous deletion and indicated that its deletion spans 730-970 kb. Candidate genes PRLTS (PDGF-receptor {beta}-like tumor suppressor) and CTSB (cathepsin B) are located outside the region of homozygous deletion. Genethon marker D8S549 is located approximately at the center of this region of homozygous deletion. Two new microsatellite polymorphisms, D8S1991 and D8S1992, also located within the region of homozygous deletion on chromosome 8p22, are described. Physical mapping places cosmid CI8-2644 telomeric to MSR (macrophage scavenger receptor), the reverse of a previously published map, altering the interpretation of published deletion studies. This work should prove helpful in the identification of candidate tumor suppressor genes in this region. 47 refs., 5 figs., 1 tab.

Role of KEAP1/NRF2 and TP53 mutations in lung squamous cell carcinoma development and radiotherapy response prediction

Science.gov (United States)

Jeong, Youngtae; Hoang, Ngoc T.; Lovejoy, Alexander; Stehr, Henning; Newman, Aaron M.; Gentles, Andrew J.; Kong, William; Truong, Diana; Martin, Shanique; Chaudhuri, Aadel; Heiser, Diane; Zhou, Li; Say, Carmen; Carter, Justin N.; Hiniker, Susan M.; Loo, Billy W.; West, Robert B.; Beachy, Philip; Alizadeh, Ash A.; Diehn, Maximilian

2016-01-01

Lung squamous cell carcinomas (LSCC) pathogenesis remains incompletely understood and biomarkers predicting treatment response remain lacking. Here we describe novel murine LSCC models driven by loss of Trp53 and Keap1, both of which are frequently mutated in human LSCCs. Homozygous inactivation of Keap1 or Trp53 promoted airway basal stem cell (ABSC) self-renewal, suggesting that mutations in these genes lead to expansion of mutant stem cell clones. Deletion of Trp53 and Keap1 in ABSCs, but not more differentiated tracheal cells, produced tumors recapitulating histological and molecular features of human LSCCs, indicating that they represent the likely cell of origin in this model. Deletion of Keap1 promoted tumor aggressiveness, metastasis, and resistance to oxidative stress and radiotherapy (RT). KEAP1/NRF2 mutation status predicted risk of local recurrence after RT in non-small lung cancer (NSCLC) patients and could be non-invasively identified in circulating tumor DNA. Thus, KEAP1/NRF2 mutations could serve as predictive biomarkers for personalization of therapeutic strategies for NSCLCs. PMID:27663899

Heterozygous and homozygous JAK2(V617F states modeled by induced pluripotent stem cells from myeloproliferative neoplasm patients.

Directory of Open Access Journals (Sweden)

Joseph Saliba

Full Text Available JAK2(V617F is the predominant mutation in myeloproliferative neoplasms (MPN. Modeling MPN in a human context might be helpful for the screening of molecules targeting JAK2 and its intracellular signaling. We describe here the derivation of induced pluripotent stem (iPS cell lines from 2 polycythemia vera patients carrying a heterozygous and a homozygous mutated JAK2(V617F, respectively. In the patient with homozygous JAK2(V617F, additional ASXL1 mutation and chromosome 20 allowed partial delineation of the clonal architecture and assignation of the cellular origin of the derived iPS cell lines. The marked difference in the response to erythropoietin (EPO between homozygous and heterozygous cell lines correlated with the constitutive activation level of signaling pathways. Strikingly, heterozygous iPS cells showed thrombopoietin (TPO-independent formation of megakaryocytic colonies, but not EPO-independent erythroid colony formation. JAK2, PI3K and HSP90 inhibitors were able to block spontaneous and EPO-induced growth of erythroid colonies from GPA(+CD41(+ cells derived from iPS cells. Altogether, this study brings the proof of concept that iPS can be used for studying MPN pathogenesis, clonal architecture, and drug efficacy.

Identification of a homozygous PSTPIP1 mutation in a patient with a PAPA-like syndrome responding to canakinumab treatment.

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Geusau, Alexandra; Mothes-Luksch, Nadine; Nahavandi, Hesam; Pickl, Winfried F; Wise, Carol A; Pourpak, Zahra; Ponweiser, Elisabeth; Eckhart, Leopold; Sunder-Plassmann, Raute

2013-02-01

Pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome (OMIM 604416) is a rare autosomal dominant inherited autoinflammatory syndrome characterized by pyogenic sterile arthritis and less frequently accompanied by pyoderma gangrenosum and acne. It is associated with dominant missense mutations in the proline-serine-threonine phosphatase-interacting protein 1 gene (PSTPIP1) located on chromosome 15. The patient was diagnosed as having features of a PAPA-like syndrome in which cutaneous manifestations, such as pyoderma gangrenosum and acne fulminans, predominated. Sequencing of the PSTPIP1 gene was performed in the patient and his extended family. The patient's DNA analysis revealed a homozygous nucleotide exchange c.773G>C in the PSTPIP1 gene, leading to the substitution of glycine 258 by alanine (p.Gly258Ala), a previously reported heterozygous polymorphism. Heterozygous changes were identified in both of the patient's parents and in 7 other family members, all of whom were asymptomatic. The patient was treated with canakinumab, a human anti-interleukin 1β monoclonal antibody, which led to rapid remission of the symptoms. To our knowledge, this is the first reported case of the resolution of dermatological symptoms associated with a PAPA-like syndrome using canakinumab treatment. Further study of the p.Gly258Ala variant is warranted to determine whether this mutation has a role in causing an apparently recessive cutaneous syndrome resembling PAPA syndrome.

Two novel mutations in the BCKDK (branched-chain keto-acid dehydrogenase kinase) gene are responsible for a neurobehavioral deficit in two pediatric unrelated patients.

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García-Cazorla, Angels; Oyarzabal, Alfonso; Fort, Joana; Robles, Concepción; Castejón, Esperanza; Ruiz-Sala, Pedro; Bodoy, Susanna; Merinero, Begoña; Lopez-Sala, Anna; Dopazo, Joaquín; Nunes, Virginia; Ugarte, Magdalena; Artuch, Rafael; Palacín, Manuel; Rodríguez-Pombo, Pilar; Alcaide, Patricia; Navarrete, Rosa; Sanz, Paloma; Font-Llitjós, Mariona; Vilaseca, Ma Antonia; Ormaizabal, Aida; Pristoupilova, Anna; Agulló, Sergi Beltran

2014-04-01

Inactivating mutations in the BCKDK gene, which codes for the kinase responsible for the negative regulation of the branched-chain α-keto acid dehydrogenase complex (BCKD), have recently been associated with a form of autism in three families. In this work, two novel exonic BCKDK mutations, c.520C>G/p.R174G and c.1166T>C/p.L389P, were identified at the homozygous state in two unrelated children with persistently reduced body fluid levels of branched-chain amino acids (BCAAs), developmental delay, microcephaly, and neurobehavioral abnormalities. Functional analysis of the mutations confirmed the missense character of the c.1166T>C change and showed a splicing defect r.[520c>g;521_543del]/p.R174Gfs1*, for c.520C>G due to the presence of a new donor splice site. Mutation p.L389P showed total loss of kinase activity. Moreover, patient-derived fibroblasts showed undetectable (p.R174Gfs1*) or barely detectable (p.L389P) levels of BCKDK protein and its phosphorylated substrate (phospho-E1α), resulting in increased BCKD activity and the very rapid BCAA catabolism manifested by the patients' clinical phenotype. Based on these results, a protein-rich diet plus oral BCAA supplementation was implemented in the patient homozygous for p.R174Gfs1*. This treatment normalized plasma BCAA levels and improved growth, developmental and behavioral variables. Our results demonstrate that BCKDK mutations can result in neurobehavioral deficits in humans and support the rationale for dietary intervention. © 2014 WILEY PERIODICALS, INC.

New insights into thyroglobulin gene: molecular analysis of seven novel mutations associated with goiter and hypothyroidism.

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Citterio, Cintia E; Machiavelli, Gloria A; Miras, Mirta B; Gruñeiro-Papendieck, Laura; Lachlan, Katherine; Sobrero, Gabriela; Chiesa, Ana; Walker, Joanna; Muñoz, Liliana; Testa, Graciela; Belforte, Fiorella S; González-Sarmiento, Rogelio; Rivolta, Carina M; Targovnik, Héctor M

2013-01-30

The thyroglobulin (TG) gene is organized in 48 exons, spanning over 270 kb on human chromosome 8q24. Up to now, 62 inactivating mutations in the TG gene have been identified in patients with congenital goiter and endemic or non-endemic simple goiter. The purpose of the present study was to identify and characterize new mutations in the TG gene. We report 13 patients from seven unrelated families with goiter, hypothyroidism and low levels of serum TG. All patients underwent clinical, biochemical and imaging evaluation. Single-strand conformation polymorphism (SSCP) analysis, endonuclease restriction analysis, sequencing of DNA, genotyping, population screening, and bioinformatics studies were performed. Molecular analyses revealed seven novel inactivating TG mutations: c.378C>A [p.Y107X], c.2359C>T [p.R768X], c.2736delG [p.R893fsX946], c.3842G>A [p.C1262Y], c.5466delA [p.K1803fsX1833], c.6000C>G [p.C1981W] and c.6605C>G [p.P2183R] and three previously reported mutations: c.886C>T [p.R277X], c.6701C>A [p.A2215D] and c.7006C>T [p.R2317X]. Six patients from two families were homozygous for p.R277X mutation, four were compound heterozygous mutations (p.Y107X/p.C1262Y, p.R893fsX946/p.A2215D, p.K1803fsX1832/p.R2317X), one carried three identified mutations (p.R277X/p.C1981W-p.P2183R) together with a hypothetical micro deletion and the remaining two siblings from another family with typical phenotype had a single p.R768X mutated allele. In conclusion, our results confirm the genetic heterogeneity of TG defects and the pathophysiological importance of altered TG folding as a consequency of truncated TG proteins and missense mutations located in ACHE-like domain or that replace cysteine. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Inactivation of Smad4 in gastric carcinomas.

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Powell, S M; Harper, J C; Hamilton, S R; Robinson, C R; Cummings, O W

1997-10-01

Allelic loss of chromosome 18q has been noted in intestinal type gastric adenocarcinomas. Smad4 is a gene located at 18q that was recently cloned in humans and found to be significantly altered in pancreatic cancers. We sought to determine whether Smad4 genetic alterations played a significant role in gastric tumorigenesis by studying 35 gastric adenocarcinomas of all histopathological types and pathological stages. Microdissected specimens were used for mutational analysis of Smad4 at the nucleotide level, including the entire coding region and intron/exon boundaries. Allelic imbalance was also analyzed at the Smad4 locus using two nearby microsatellite markers. One case of apparent biallelic inactivation of Smad4 was found in our study of 35 gastric carcinomas. A nonsense point mutation at codon 334 was demonstrated, which, similar to other Smad4 mutations, is predicted to truncate the conserved COOH-terminal domain of this protein. This Smad4 C to T transition mutation was proven to be somatically acquired. Allelic loss was also noted on chromosome 18q at a marker near Smad4 in this mutated gastric cancer, apparently producing complete inactivation of Smad4 in this tumor. Significant 18q allelic loss (56% of 34 informative cases) was noted in our gastric carcinomas using microsatellite markers near the Smad4 locus, regardless of histological subtype or pathological stage. Additionally, three cases of microsatellite instability were observed. Thus, Smad4 inactivation was noted in our gastric carcinomas; however, this event was rare. The frequent loss of chromosomal arm 18q observed in gastric cancers suggests the presence of other tumor suppressor genes in this region that are involved in gastric tumorigenesis. Further studies are needed to identify these other targets of inactivation during gastric cancer development.

Copy number neutral loss of heterozygosity at 17p and homozygous mutations of TP53 are associated with complex chromosomal aberrations in patients newly diagnosed with myelodysplastic syndromes.

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Svobodova, Karla; Zemanova, Zuzana; Lhotska, Halka; Novakova, Milena; Podskalska, Lucie; Belickova, Monika; Brezinova, Jana; Sarova, Iveta; Izakova, Silvia; Lizcova, Libuse; Berkova, Adela; Siskova, Magda; Jonasova, Anna; Cermak, Jaroslav; Michalova, Kyra

2016-03-01

Complex karyotypes are seen in approximately 20% of patients with myelodysplastic syndromes (MDS) and are associated with a high risk of transformation to acute myeloid leukemia and poor outcomes in patients. Copy number neutral loss of heterozygosity (CN-LOH, i.e., both copies of a chromosomal pair or their parts originate from one parent) might contribute to increased genomic instability in the bone-marrow cells of patients with MDS. The pathological potential of CN-LOH, which arises as a clonal aberration in a proportion of somatic cells, consists of tumor suppressor gene and oncogene homozygous mutations. The aim of our study was to evaluate the frequency of CN-LOH at 17p in bone-marrow cells of newly diagnosed MDS patients with complex chromosomal aberrations and to assess its correlation with mutations in the TP53 gene (17p13.1). CN-LOH was detected in 40 chromosomal regions in 21 (29%) of 72 patients analyzed. The changes in 27 of the 40 regions identified were sporadic. The most common finding was CN-LOH of the short arm of chromosome 17, which was detected in 13 (18%) of 72 patients. A mutational analysis confirmed the homozygous mutation of TP53 in all CN-LOH 17p patients, among which two frameshift mutations are not registered in the International Agency for Research on Cancer TP53 Database. CN-LOH 17p correlated with aggressive disease (median overall survival 4 months) and was strongly associated with a complex karyotype in the cohort studied, which might cause rapid disease progression in high-risk MDS. No other CN-LOH region previously recorded in MDS or AML patients (1p, 4q, 7q, 11q, 13q, 19q, 21q) was detected in our cohort of patients with complex karyotype examined at the diagnosis of MDS. The LOH region appeared to be balanced (i.e., with no DNA copy number change) when examined with conventional and molecular cytogenetic methods. Therefore, a microarray that detects single-nucleotide polymorphisms is an ideal method with which to identify and

Dietary factors and Truncating APC Mutations in Sporadic Colorectal Adenomas

NARCIS (Netherlands)

Diergaarde, B.; Tiemersma, E.W.; Braam, H.; Muijen, van G.N.P.; Nagengast, F.M.; Kok, F.J.; Kampman, E.

2005-01-01

Inactivating mutations in APC are thought to be early, initiating events in colorectal carcinogenesis. To gain insight into the relationship between diet and inactivating APC mutations, we evaluated associations between dietary factors and the occurrence of these mutations in a Dutch case-control

Dietary factors and truncating APC mutations in sporadic colorectal adenomas.

NARCIS (Netherlands)

Diergaarde, B.; Tiemersma, E.W.; Braam, H.; Muijen, G.N.P. van; Nagengast, F.M.; Kok, F.J.; Kampman, E.

2005-01-01

Inactivating mutations in APC are thought to be early, initiating events in colorectal carcinogenesis. To gain insight into the relationship between diet and inactivating APC mutations, we evaluated associations between dietary factors and the occurrence of these mutations in a Dutch case-control

Clinical expression of patients with the D1152H CFTR mutation.

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Terlizzi, Vito; Carnovale, Vincenzo; Castaldo, Giuseppe; Castellani, Carlo; Cirilli, Natalia; Colombo, Carla; Corti, Fabiola; Cresta, Federico; D'Adda, Alice; Lucarelli, Marco; Lucidi, Vincenzina; Macchiaroli, Annamaria; Madarena, Elisa; Padoan, Rita; Quattrucci, Serena; Salvatore, Donatello; Zarrilli, Federica; Raia, Valeria

2015-07-01

Discordant results were reported on the clinical expression of subjects bearing the D1152H CFTR mutation, and also for the small number of cases reported so far. A retrospective review of clinical, genetic and biochemical data was performed from individuals homozygous or compound heterozygous for the D1152H mutation followed in 12 Italian cystic fibrosis (CF) centers. 89 subjects carrying at least D1152H on one allele were identified. 7 homozygous patients had very mild clinical expression. Over half of the 74 subjects compound heterozygous for D1152H and a I-II-III class mutation had borderline or pathological sweat test and respiratory or gastrointestinal symptoms; one third had pulmonary bacteria colonization and 10/74 cases had complications (i.e. diabetes, allergic bronchopulmonary aspergillosis, and hemoptysis). However, their clinical expression was less severe as compared to a group of CF patients homozygous for the F508del mutation. Finally, 8 subjects compound heterozygous for D1152H and a IV-V class mutation showed very mild disease. The natural history of subjects bearing the D1152H mutation is widely heterogeneous and is influenced by the mutation in trans. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Whole-Exome Sequencing Identifies Homozygous AFG3L2 Mutations in a Spastic Ataxia-Neuropathy Syndrome Linked to Mitochondrial m-AAA Proteases

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Martinelli, Paola; Cherukuri, Praveen F.; Teer, Jamie K.; Hansen, Nancy F.; Cruz, Pedro; Mullikin for the NISC Comparative Sequencing Program, James C.; Blakesley, Robert W.; Golas, Gretchen; Kwan, Justin; Sandler, Anthony; Fuentes Fajardo, Karin; Markello, Thomas; Tifft, Cynthia; Blackstone, Craig; Rugarli, Elena I.; Langer, Thomas; Gahl, William A.; Toro, Camilo

2011-01-01

We report an early onset spastic ataxia-neuropathy syndrome in two brothers of a consanguineous family characterized clinically by lower extremity spasticity, peripheral neuropathy, ptosis, oculomotor apraxia, dystonia, cerebellar atrophy, and progressive myoclonic epilepsy. Whole-exome sequencing identified a homozygous missense mutation (c.1847G>A; p.Y616C) in AFG3L2, encoding a subunit of an m-AAA protease. m-AAA proteases reside in the mitochondrial inner membrane and are responsible for removal of damaged or misfolded proteins and proteolytic activation of essential mitochondrial proteins. AFG3L2 forms either a homo-oligomeric isoenzyme or a hetero-oligomeric complex with paraplegin, a homologous protein mutated in hereditary spastic paraplegia type 7 (SPG7). Heterozygous loss-of-function mutations in AFG3L2 cause autosomal-dominant spinocerebellar ataxia type 28 (SCA28), a disorder whose phenotype is strikingly different from that of our patients. As defined in yeast complementation assays, the AFG3L2Y616C gene product is a hypomorphic variant that exhibited oligomerization defects in yeast as well as in patient fibroblasts. Specifically, the formation of AFG3L2Y616C complexes was impaired, both with itself and to a greater extent with paraplegin. This produced an early-onset clinical syndrome that combines the severe phenotypes of SPG7 and SCA28, in additional to other “mitochondrial” features such as oculomotor apraxia, extrapyramidal dysfunction, and myoclonic epilepsy. These findings expand the phenotype associated with AFG3L2 mutations and suggest that AFG3L2-related disease should be considered in the differential diagnosis of spastic ataxias. PMID:22022284

Whole-exome sequencing identifies homozygous AFG3L2 mutations in a spastic ataxia-neuropathy syndrome linked to mitochondrial m-AAA proteases.

Directory of Open Access Journals (Sweden)

Tyler Mark Pierson

2011-10-01

Full Text Available We report an early onset spastic ataxia-neuropathy syndrome in two brothers of a consanguineous family characterized clinically by lower extremity spasticity, peripheral neuropathy, ptosis, oculomotor apraxia, dystonia, cerebellar atrophy, and progressive myoclonic epilepsy. Whole-exome sequencing identified a homozygous missense mutation (c.1847G>A; p.Y616C in AFG3L2, encoding a subunit of an m-AAA protease. m-AAA proteases reside in the mitochondrial inner membrane and are responsible for removal of damaged or misfolded proteins and proteolytic activation of essential mitochondrial proteins. AFG3L2 forms either a homo-oligomeric isoenzyme or a hetero-oligomeric complex with paraplegin, a homologous protein mutated in hereditary spastic paraplegia type 7 (SPG7. Heterozygous loss-of-function mutations in AFG3L2 cause autosomal-dominant spinocerebellar ataxia type 28 (SCA28, a disorder whose phenotype is strikingly different from that of our patients. As defined in yeast complementation assays, the AFG3L2(Y616C gene product is a hypomorphic variant that exhibited oligomerization defects in yeast as well as in patient fibroblasts. Specifically, the formation of AFG3L2(Y616C complexes was impaired, both with itself and to a greater extent with paraplegin. This produced an early-onset clinical syndrome that combines the severe phenotypes of SPG7 and SCA28, in additional to other "mitochondrial" features such as oculomotor apraxia, extrapyramidal dysfunction, and myoclonic epilepsy. These findings expand the phenotype associated with AFG3L2 mutations and suggest that AFG3L2-related disease should be considered in the differential diagnosis of spastic ataxias.

X inactivation in females with X-linked Charcot-Marie-Tooth disease.

LENUS (Irish Health Repository)

Murphy, Sinéad M

2012-07-01

X-linked Charcot-Marie-Tooth disease (CMT1X) is the second most common inherited neuropathy, caused by mutations in gap junction beta-1 (GJB1). Males have a uniformly moderately severe phenotype while females have a variable phenotype, suggested to be due to X inactivation. We aimed to assess X inactivation pattern in females with CMT1X and correlate this with phenotype using the CMT examination score to determine whether the X inactivation pattern accounted for the variable phenotype in females with CMT1X. We determined X inactivation pattern in 67 females with CMT1X and 24 controls using the androgen receptor assay. We were able to determine which X chromosome carried the GJB1 mutation in 30 females. There was no difference in X inactivation pattern between patients and controls. In addition, there was no correlation between X inactivation pattern in blood and phenotype. A possible explanation for these findings is that the X inactivation pattern in Schwann cells rather than in blood may explain the variable phenotype in females with CMT1X.

Personalized Stem Cell Therapy to Correct Corneal Defects Due to a Unique Homozygous-Heterozygous Mosaicism of Ectrodactyly-Ectodermal Dysplasia-Clefting Syndrome.

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Barbaro, Vanessa; Nasti, Annamaria Assunta; Raffa, Paolo; Migliorati, Angelo; Nespeca, Patrizia; Ferrari, Stefano; Palumbo, Elisa; Bertolin, Marina; Breda, Claudia; Miceli, Francesco; Russo, Antonella; Caenazzo, Luciana; Ponzin, Diego; Palù, Giorgio; Parolin, Cristina; Di Iorio, Enzo

2016-08-01

: Ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome is a rare autosomal dominant disease caused by mutations in the p63 gene. To date, approximately 40 different p63 mutations have been identified, all heterozygous. No definitive treatments are available to counteract and resolve the progressive corneal degeneration due to a premature aging of limbal epithelial stem cells. Here, we describe a unique case of a young female patient, aged 18 years, with EEC and corneal dysfunction, who was, surprisingly, homozygous for a novel and de novo R311K missense mutation in the p63 gene. A detailed analysis of the degree of somatic mosaicism in leukocytes from peripheral blood and oral mucosal epithelial stem cells (OMESCs) from biopsies of buccal mucosa showed that approximately 80% were homozygous mutant cells and 20% were heterozygous. Cytogenetic and molecular analyses excluded genomic alterations, thus suggesting a de novo mutation followed by an allelic gene conversion of the wild-type allele by de novo mutant allele as a possible mechanism to explain the homozygous condition. R311K-p63 OMESCs were expanded in vitro and heterozygous holoclones selected following clonal analysis. These R311K-p63 OMESCs were able to generate well-organized and stratified epithelia in vitro, resembling the features of healthy tissues. This study supports the rationale for the development of cultured autologous oral mucosal epithelial stem cell sheets obtained by selected heterozygous R311K-p63 stem cells, as an effective and personalized therapy for reconstructing the ocular surface of this unique case of EEC syndrome, thus bypassing gene therapy approaches. This case demonstrates that in a somatic mosaicism context, a novel homozygous mutation in the p63 gene can arise as a consequence of an allelic gene conversion event, subsequent to a de novo mutation. The heterozygous mutant R311K-p63 stem cells can be isolated by means of clonal analysis and given their good regenerative

Similarities and discrepancies in homozygous factor VII defects due to mutations in the region of residues Met298 to Cys310 (exon 8) in the catalytic domain of factor VII.

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Girolami, A; Berti de Marinis, G; Bonamigo, E; Vettore, S

2011-06-01

Patients with the Arg304Gln mutation in factor VII Padua (FVII Padua) show discrepant activity levels that depend on the thromboplastin used in the assay system. This report investigates the possibility that residues close to Arg304 (exon 8) show the same discrepant behavior. All available homozygous patients with a mutation in a 13-residue region (preceding and following Arg304) have been evaluated. Only the Arg304Trp mutation showed a discrepancy similar to that shown by the Arg304Gln mutation. Other homozygotes failed to show differences, despite their all being positive for cross-reacting material. Another FVII amino acid residue involved in tissue factor binding and activation is Arg79 (exon 4). No comparison could be carried out because no homozygotes for deficiency in this region have ever been described. The relationship between these 2 residues involved in tissue factor binding and activation has not yet been completely clarified; however, Arg residues 79 and 304 are the only 2 residues definitely shown thus far to be involved in this important function.

CNGA3 mutations in two United Arab Emirates families with achromatopsia.

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Ahuja, Yachna; Kohl, Susanne; Traboulsi, Elias I

2008-07-10

ACHROMATOPSIA RESULTS FROM MUTATIONS IN ONE OF THREE GENES: cyclic nucleotide-gated channel, alpha-3 (CNGA3); cyclic nucleotide-gated channel, beta-3 (CNGB3); and guanine nucleotide-binding protein, alpha-transducing activity polypeptide 2 (GNAT2). We report the responsible mutations in two United Arab Emirates families who have this autosomal recessive disease. Clinical examinations were performed in seven patients from three nuclear families. Molecular genetic testing for common CNGA3 and CNGB3 mutations was undertaken using standard protocols. All patients were extremely light sensitive and had reduced visual acuity and no color perception. Fundus examinations did not show any visible abnormalities. After further pedigree analysis, two of the families were found to be linked through the paternal line. Two mutations in CNGA3 were identified: Arg283Trp and Gly397Val. Family A, the larger pedigree, had one branch in which two sisters and one brother were homozygous for the Gly397Val mutation and another branch in which a brother and sister were compound heterozygous for both aforenamed mutations. Family B, however, only had two brothers who were homozygous for the Arg283Trp mutation. Achromatopsia in these two United Arab Emirates families results from two different mutations in CNGA3. Two branches of the same pedigree had individuals with both homozygous and compound heterozygous disease, demonstrating a complex molecular pathology in this large family.

[A novel homozygous mutation p.E25X in the HSD3B2 gene causing salt wasting 3β-hydroxysteroid dehydrogenases deficiency in a Chinese pubertal girl: a delayed diagnosis until recurrent ovary cysts].

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Huang, Yonglan; Zheng, Jipeng; Xie, Ting; Xiao, Qing; Lu, Shaomei; Li, Xiuzhen; Cheng, Jing; Chen, Lihe; Liu, Li

2014-12-01

3β- hydroxysteroid dehydrogenase deficiency (3βHSD), a rare form of congenital adrenal hyperplasia (CAH) resulted from mutations in the HSD3B2 gene that impair steroidogenesis in both adrenals and gonads. We report clinical features and the results of HSD3B2 gene analysis of a Chinese pubertal girl with salt wasting 3βHSD deficiency. We retrospectively reviewed clinical presentations and steroid profiles of the patient diagnosed in Guangzhou Women and Children's Medical Center in 2013. PCR and direct sequencing were used to identify any mutation in the HSD3B2 gene. A 13-year-old girl was diagnosed as CAH after birth because of salt-wasting with mild clitorimegaly and then was treated with glucocorticoid replacement. Breast and pubic hair development were normal, and menarche occurred at 12 yr, followed by menstrual bleeding about every 45 days. In the last one year laparoscopic operation and ovariocentesis were performed one after another for recurrent ovary cysts. Under corticoid acetate therapy, ACTH 17.10 pmol/L (normal 0-10.12), testosterone 1.31 nmol/L (normal T (p.E25X) was identified in HSD3B2 gene. The girl was homozygous and her mother was heterozygous, while her father was not identified with this mutation. A classic 3βHSD deficiency is characterized by salt wasting and mild virilization in female. Ovary cysts may be the one of features of gonad phenotype indicating ovary 3βHSD deficiency. A novel homozygous mutation c.73G >T(p.E25X) was related to the classical phenotype.

[Association between homozygous c.318A>GT mutation in exon 2 of the EIF2B5 gene and the infantile form of vanishing white matter leukoencephalopathy].

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Esmer, Carmen; Blanco Hernández, Gabriela; Saavedra Alanís, Víctor; Reyes Vaca, Jorge Guillermo; Bravo Oro, Antonio

Vanishing white matter disease is one of the most frequent leukodystrophies in childhood with an autosomal recessive inheritance. A mutation in one of the genes encoding the five subunits of the eukaryotic initiation factor 2 (EIF2B5) is present in 90% of the cases. The diagnosis can be accomplished by the clinical and neuroradiological findings and molecular tests. We describe a thirteen-month-old male with previous normal neurodevelopment, who was hospitalized for vomiting, hyperthermia and irritability. On examination, cephalic perimeter and cranial pairs were normal. Hypotonia, increased muscle stretching reflexes, generalized white matter hypodensity on cranial tomography were found. Fifteen days after discharge, he suffered minor head trauma presenting drowsiness and focal seizures. Magnetic resonance showed generalized hypointensity of white matter. Vanishing white matter disease was suspected, and confirmed by sequencing of the EIF2B5 gene, revealing a homozygous c.318A> T mutation in exon 2. Subsequently, visual acuity was lost and cognitive and motor deterioration was evident. The patient died at six years of age due to severe pneumonia. This case contributes to the knowledge of the mutational spectrum present in Mexican patients and allows to extend the phenotype associated to this mutation. Copyright © 2017. Publicado por Masson Doyma México S.A.

A homozygous mutation in RNU4ATAC as a cause of microcephalic osteodysplastic primordial dwarfism type I (MOPD I) with associated pigmentary disorder.

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Abdel-Salam, Ghada M H; Miyake, Noriko; Eid, Maha M; Abdel-Hamid, Mohamed S; Hassan, Nihal A; Eid, Ola M; Effat, Laila K; El-Badry, Tarek H; El-Kamah, Ghada Y; El-Darouti, Mohamed; Matsumoto, Naomichi

2011-11-01

The designation microcephalic osteodysplastic primordial dwarfism (MOPD) refers to a group of autosomal recessive disorders, comprising microcephaly, growth retardation, and a skeletal dysplasia. The different types of MOPD have been delineated on the basis of clinical, radiological, and genetic criteria. We describe two brothers, born to healthy, consanguineous parents, with intrauterine and postnatal growth retardation, microcephaly with abnormal gyral pattern and partial agenesis of corpus callosum, and skeletal anomalies reminiscent of those described in MOPD type I. This was confirmed by the identification of the homozygous g.55G > A mutation of RNU4ATAC encoding U4atac snRNA. The sibs had yellowish-gray hair, fair skin, and deficient retinal pigmentation. Skin biopsy showed abnormal melanin function but OCA genes were normal. The older sib had an intracranial hemorrhage at 1 week after birth, the younger developed chilblains-like lesions at the age 2½ years old but analysis of the SAMHD1 and TREX1 genes did not show any mutations. To the best of our knowledge, vasculopathy and pigmentary disorders have not been reported in MOPD I. Copyright © 2011 Wiley Periodicals, Inc.

[Analysis of USH2A gene mutation in a Chinese family affected with Usher syndrome].

Science.gov (United States)

Li, Pengcheng; Liu, Fei; Zhang, Mingchang; Wang, Qiufen; Liu, Mugen

2015-08-01

To investigate the disease-causing mutation in a Chinese family affected with Usher syndrome type II. All of the 11 members from the family underwent comprehensive ophthalmologic examination and hearing test, and their genomic DNA were isolated from venous leukocytes. PCR and direct sequencing of USH2A gene were performed for the proband. Wild type and mutant type minigene vectors containing exon 42, intron 42 and exon 43 of the USH2A gene were constructed and transfected into Hela cells by lipofectamine reagent. Reverse transcription (RT)-PCR was carried out to verify the splicing of the minigenes. Pedigree analysis and clinical diagnosis indicated that the patients have suffered from autosomal recessive Usher syndrome type II. DNA sequencing has detected a homozygous c.8559-2A>G mutation of the USH2A gene in the proband, which has co-segregated with the disease in the family. The mutation has affected a conserved splice site in intron 42, which has led to inactivation of the splice site. Minigene experiment has confirmed the retaining of intron 42 in mature mRNA. The c.8559-2A>G mutation in the USH2A gene probably underlies the Usher syndrome type II in this family. The splice site mutation has resulted in abnormal splicing of USH2A pre-mRNA.

Efficacy of Rosuvastatin in Children With Homozygous Familial Hypercholesterolemia and Association With Underlying Genetic Mutations

NARCIS (Netherlands)

Stein, Evan A.; Dann, Eldad J.; Wiegman, Albert; Skovby, Flemming; Gaudet, Daniel; Sokal, Etienne; Charng, Min-Ji; Mohamed, Mafauzy; Luirink, Ilse; Raichlen, Joel S.; Sundén, Mattias; Carlsson, Stefan C.; Raal, Frederick J.; Kastelein, John J. P.

2017-01-01

BACKGROUND Homozygous familial hypercholesterolemia (HoFH), a rare genetic disorder, is characterized by extremely elevated levels of low-density lipoprotein cholesterol (LDL-C) and accelerated atherosclerotic cardiovascular disease. Statin treatment starts at diagnosis, but no statin has been

Targeted next-generation sequencing identifies a homozygous nonsense mutation in ABHD12, the gene underlying PHARC, in a family clinically diagnosed with Usher syndrome type 3.

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Eisenberger, Tobias; Slim, Rima; Mansour, Ahmad; Nauck, Markus; Nürnberg, Gudrun; Nürnberg, Peter; Decker, Christian; Dafinger, Claudia; Ebermann, Inga; Bergmann, Carsten; Bolz, Hanno Jörn

2012-09-02

Usher syndrome (USH) is an autosomal recessive genetically heterogeneous disorder with congenital sensorineural hearing impairment and retinitis pigmentosa (RP). We have identified a consanguineous Lebanese family with two affected members displaying progressive hearing loss, RP and cataracts, therefore clinically diagnosed as USH type 3 (USH3). Our study was aimed at the identification of the causative mutation in this USH3-like family. Candidate loci were identified using genomewide SNP-array-based homozygosity mapping followed by targeted enrichment and next-generation sequencing. Using a capture array targeting the three identified homozygosity-by-descent regions on chromosomes 1q43-q44, 20p13-p12.2 and 20p11.23-q12, we identified a homozygous nonsense mutation, p.Arg65X, in ABHD12 segregating with the phenotype. Mutations of ABHD12, an enzyme hydrolyzing an endocannabinoid lipid transmitter, cause PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract). After the identification of the ABHD12 mutation in this family, one patient underwent neurological examination which revealed ataxia, but no polyneuropathy. ABHD12 is not known to be related to the USH protein interactome. The phenotype of our patient represents a variant of PHARC, an entity that should be taken into account as differential diagnosis for USH3. Our study demonstrates the potential of comprehensive genetic analysis for improving the clinical diagnosis.

Inactivation and mutation of cultured mammalian cells by aluminium characteristic ultrasoft X-rays

International Nuclear Information System (INIS)

Goodhead, D.T.

1977-01-01

Microdosimetric distributions for aluminium K characteristic ultrasoft X-rays and 4 He ion track intersections have been calculated and used to analyse recent biological results obtained with these radiations. Results on inactivation and mutation-induction to thioguanine resistance of both V79 Chinese hamster cells and HF19 human diploid fibroblasts in vitro were analysed in terms of the Kellerer-Rossi 'theory of dual radiation action'. The small quantum energy of the aluminium X-ray photons and the very short length of the secondary electrons which they produce highlight the inadequacy of the model. It has been shown that the model predicted r.b.e. values in conflict with those observed unless an additional variable was introduced, but that the introduction of such a variable created mathematical inconsistencies. The experimental evidence is contrary to the conventional usage and basis of the model. (author)

Making (mis) sense of asymptomatic marked hypercalcemia in pregnancy.

Science.gov (United States)

Maltese, Giuseppe; Izatt, Louise; McGowan, Barbara M; Hafeez, Kashif; Hubbard, Johnathan G; Carroll, Paul V

2017-10-01

We describe a rare case of homozygous inactivating calcium-sensing receptor mutation detected during pregnancy and mimicking primary hyperparathyroidism. In pregnancy, the differential diagnosis of hypercalcaemia requires a cautious approach as physiological changes in calcium homeostasis may mask rare genetic conditions.

A novel homozygous Arg222Trp missense mutation in WNT7A in two sisters with severe Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome.

Science.gov (United States)

Kantaputra, Piranit N; Mundlos, Stefan; Sripathomsawat, Warissara

2010-11-01

Al-Awadi/Raas-Rothschild/Schinzel phocomelia (AARRS) syndrome, a rare autosomal recessive disorder, comprises malformations of upper and lower limbs with severely hypoplastic pelvis and abnormal genitalia. Mutations in WNT7A have been reported as cause of the syndrome. We report on two sisters in a Thai family with short and malformed long bones, absent fibulae, flexion contracture of digits, and a/hypoplastic nails. Fusion between severely malformed femora and slender tibiae has never been reported in patients with WNT7A mutations. Lower limbs were more severely malformed than the upper ones and the pelvis was also severely affected. Multiple fusions of long bones and of the femoral heads to the acetabula were evident. A novel homozygous missense mutation in coding exon 4 of the WNT7A was detected in both affected daughters (c.664C > T) leading to an amino acid exchange from arginine to tryptophan (p.Arg222Trp; R222W). The phenotype is likely to result from an abnormality of all three signaling centers in the developing limb resulting in ventralization with a loss of dorsal structures (aplasia/hypoplasia of nails) a loss of anterior-posterior identity (single distal bones in lower limb without polarity) and an outgrowth defect resulting in distal truncations. © 2010 Wiley-Liss, Inc.

Mutation and Expression of the DCC Gene in Human Lung Cancer

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Takashi Kohno

2000-07-01

Full Text Available Chromosome 18q is frequently deleted in lung cancers, a common region of 18q deletions was mapped to chromosome 18g21. Since the DCC candidate tumor suppressor gene has been mapped in this region, mutation and expression of the DCC gene were examined in 46 lung cancer cell lines, consisting of 14 small cell lung carcinomas (SCLCs and 32 non-small cell lung carcinomas (NSCLCs, to elucidate the pathogenetic significance of DCC alterations in human lung carcinogenesis. A heterozygous missense mutation was detected in a NSCLC cell line, Ma26, while homozygous deletion was not detected in any of the cell lines. The DCC gene was expressed in 11 (24% of the 46 cell lines, the incidence of DCC expression was significantly higher in SCLCs (7/14, 50% than in NSCLCs (4/32, 13% (P = .01, Fisher's exact test. Therefore, genetic alterations of DCC are infrequent; however, the levels of DCC expression vary among lung cancer cells, in particular, between SCLCs and NSCLCs. The present result does not implicate DCC as a specific mutational target of 18q deletions in human lung cancer; however, it suggests that DCC is a potential target of inactivation by genetic defects including intron or promoter mutations and/or epigenetic alterations. The present result also suggests that DCC expression is associated with some properties of SCLCs, such as a neuroendocrine (NE feature.

A family with hereditary hemochromatosis carrying HFE gene splice site mutation: a case report

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NING Huibin

2017-01-01

Full Text Available ObjectiveTo investigate a new type of HFE gene mutation in a family with hereditary hemochromatosis (HH. MethodsThe analysis of HFE gene was performed for one patient with a confirmed diagnosis of HH and five relatives. Blood genomic DNA was extracted and PCR multiplication was performed for the exon and intron splice sequences of related HFE, HJV, HAMP, transferrin receptor 2 (TfR2, and SLC40A1 genes. After agarose gel electrophoresis and purification, bi-directional direct sequencing was performed to detect mutation sites. ResultsThe proband had abnormal liver function and increases in serum iron, total iron binding capacity, serum ferritin, and transferrin saturation, as well as T→C homozygous mutation in the fourth base of intron 2 in the intervening sequence of the exon EXON2 of HFE gene (IVs 2+4T→C, C/C homozygous, splicing, abnormal. There were no abnormalities in HJV, HAMP, TfR2, and SLC40A1 genes. The proband′s son had the same homozygous mutation, three relatives had heterozygous mutations, and one relative had no abnormal mutations. ConclusionGene detection plays an important role in the diagnosis of hemochromatosis, and IVs 2+4T→C mutation may be a new pathogenic mutation for HH in China.

Recessive Mutations in ACPT, Encoding Testicular Acid Phosphatase, Cause Hypoplastic Amelogenesis Imperfecta.

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Seymen, Figen; Kim, Youn Jung; Lee, Ye Ji; Kang, Jenny; Kim, Tak-Heun; Choi, Hwajung; Koruyucu, Mine; Kasimoglu, Yelda; Tuna, Elif Bahar; Gencay, Koray; Shin, Teo Jeon; Hyun, Hong-Keun; Kim, Young-Jae; Lee, Sang-Hoon; Lee, Zang Hee; Zhang, Hong; Hu, Jan C-C; Simmer, James P; Cho, Eui-Sic; Kim, Jung-Wook

2016-11-03

Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders affecting tooth enamel. The affected enamel can be hypoplastic and/or hypomineralized. In this study, we identified ACPT (testicular acid phosphatase) biallelic mutations causing non-syndromic, generalized hypoplastic autosomal-recessive amelogenesis imperfecta (AI) in individuals from six apparently unrelated Turkish families. Families 1, 4, and 5 were affected by the homozygous ACPT mutation c.713C>T (p.Ser238Leu), family 2 by the homozygous ACPT mutation c.331C>T (p.Arg111Cys), family 3 by the homozygous ACPT mutation c.226C>T (p.Arg76Cys), and family 6 by the compound heterozygous ACPT mutations c.382G>C (p.Ala128Pro) and 397G>A (p.Glu133Lys). Analysis of the ACPT crystal structure suggests that these mutations damaged the activity of ACPT by altering the sizes and charges of key amino acid side chains, limiting accessibility of the catalytic core, and interfering with homodimerization. Immunohistochemical analysis confirmed localization of ACPT in secretory-stage ameloblasts. The study results provide evidence for the crucial function of ACPT during amelogenesis. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Function of the activated protein C (APC) autolysis loop in activated FVIII inactivation.

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Cramer, Thomas J; Gale, Andrew J

2011-06-01

Activated protein C (APC) binds to its substrates activated factor V (FVa) and activated factor VIII (FVIIIa) with a basic exosite that consists of loops 37, 60, 70 and the autolysis loop. These loops have a high density of basic residues, resulting in a positive charge on the surface of APC. Many of these residues are important in the interaction of APC with FVa and FVIIIa. The current study focused on the function of the autolysis loop in the interaction with FVIIIa. This loop was previously shown to interact with FVa, and it inhibits APC inactivation by plasma serpins. Charged residues of the autolysis loop were individually mutated to alanine and the activity of these mutants was assessed in functional FVIIIa inactivation assays. The autolysis loop was functionally important for FVIIIa inactivation. Mutation of R306, K311 and R314 each resulted in significantly reduced FVIIIa inactivation. The inactivating cleavages of FVIIIa at R336 and R562 were affected equally by the mutations. Protein S and FV stimulated cleavage at R562 more than cleavage at R336, independent of mutations in the autolysis loop. Together, these results confirmed that the autolysis loop plays a significant role as part of the basic exosite on APC in the interaction with FVIIIa. © 2011 Blackwell Publishing Ltd.

Frequency of Gγ-globin promoter -158 (C>T) XmnI polymorphism in patients with homozygous/compound heterozygous beta thalassaemia.

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Ali, Nadir; Ayyub, Muhammad; Khan, Saleem Ahmed; Ahmed, Suhaib; Abbas, Kazim; Malik, Hamid Saeed; Tashfeen, Sunila

2015-03-01

Response to hydroxyurea therapy in homozygous or compound heterozygous beta thalassaemia (BT) has been reported as more favourable in the presence of XmnI polymorphism. The prevalence of XmnI polymorphism may vary with BT phenotypes and genotypes, and differs geographically in distribution. Prevalence of XmnI polymorphism is not known in northern Pakistan. To determine the frequency of Gγ-globin promoter -158 (C>T) XmnI polymorphism (XmnI polymorphism) in patients with homozygous or compound heterozygous beta thalassaemia. Polymerase chain reaction (PCR) for common beta thalassaemia mutations and Gγ-globin promoter -158 (C>T) XmnI polymorphism was performed on 107 blood samples of transfusion dependent beta thalassaemia (BT) patients in Pakistan. One hundred samples of unrelated BT traits and 94 samples of healthy subjects as controls were also analysed for BT mutations and XmnI polymorphism. Out of 301 DNA samples, XmnI polymorphism was detected in 71(24%); in normal controls, XmnI polymorphism was detected in 34/94 (36%) subjects; while in homozygous/compound heterozygous BT, it was detected in 14/107(13%) patients (Fisher's exact test, p=.0002). In heterozygous BT group, XmnI polymorphism was detected in 23/100 subjects (Fisher's exact test, p=.03 with normal controls, and p=.049 with homozygous/compound heterozygous BT). The most common BT genotype was Frame Shift (Fr) 8-9/Fr 8-9, and none of the patients with this genotype had XmnI polymorphism. The second most common genotype was IVSI-5/IVSI-5; 4/26 (15%). Cases with this genotype had XmnI polymorphism. XmnI polymorphism in homozygous/compound heterozygous BT group is 13%. The most common genotype associated with XmnI polymorphism was IVSI-5/IVSI-5. Copyright © 2015 King Faisal Specialist Hospital & Research Centre. Published by Elsevier B.V. All rights reserved.

Targeted next-generation sequencing identifies a homozygous nonsense mutation in ABHD12, the gene underlying PHARC, in a family clinically diagnosed with Usher syndrome type 3

Science.gov (United States)

2012-01-01

Background Usher syndrome (USH) is an autosomal recessive genetically heterogeneous disorder with congenital sensorineural hearing impairment and retinitis pigmentosa (RP). We have identified a consanguineous Lebanese family with two affected members displaying progressive hearing loss, RP and cataracts, therefore clinically diagnosed as USH type 3 (USH3). Our study was aimed at the identification of the causative mutation in this USH3-like family. Methods Candidate loci were identified using genomewide SNP-array-based homozygosity mapping followed by targeted enrichment and next-generation sequencing. Results Using a capture array targeting the three identified homozygosity-by-descent regions on chromosomes 1q43-q44, 20p13-p12.2 and 20p11.23-q12, we identified a homozygous nonsense mutation, p.Arg65X, in ABHD12 segregating with the phenotype. Conclusion Mutations of ABHD12, an enzyme hydrolyzing an endocannabinoid lipid transmitter, cause PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract). After the identification of the ABHD12 mutation in this family, one patient underwent neurological examination which revealed ataxia, but no polyneuropathy. ABHD12 is not known to be related to the USH protein interactome. The phenotype of our patient represents a variant of PHARC, an entity that should be taken into account as differential diagnosis for USH3. Our study demonstrates the potential of comprehensive genetic analysis for improving the clinical diagnosis. PMID:22938382

Targeted next-generation sequencing identifies a homozygous nonsense mutation in ABHD12, the gene underlying PHARC, in a family clinically diagnosed with Usher syndrome type 3

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Eisenberger Tobias

2012-09-01

Full Text Available Abstract Background Usher syndrome (USH is an autosomal recessive genetically heterogeneous disorder with congenital sensorineural hearing impairment and retinitis pigmentosa (RP. We have identified a consanguineous Lebanese family with two affected members displaying progressive hearing loss, RP and cataracts, therefore clinically diagnosed as USH type 3 (USH3. Our study was aimed at the identification of the causative mutation in this USH3-like family. Methods Candidate loci were identified using genomewide SNP-array-based homozygosity mapping followed by targeted enrichment and next-generation sequencing. Results Using a capture array targeting the three identified homozygosity-by-descent regions on chromosomes 1q43-q44, 20p13-p12.2 and 20p11.23-q12, we identified a homozygous nonsense mutation, p.Arg65X, in ABHD12 segregating with the phenotype. Conclusion Mutations of ABHD12, an enzyme hydrolyzing an endocannabinoid lipid transmitter, cause PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract. After the identification of the ABHD12 mutation in this family, one patient underwent neurological examination which revealed ataxia, but no polyneuropathy. ABHD12 is not known to be related to the USH protein interactome. The phenotype of our patient represents a variant of PHARC, an entity that should be taken into account as differential diagnosis for USH3. Our study demonstrates the potential of comprehensive genetic analysis for improving the clinical diagnosis.

Identification of homozygous WFS1 mutations (p.Asp211Asn, p.Gln486*) causing severe Wolfram syndrome and first report of male fertility.

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Haghighi, Amirreza; Haghighi, Alireza; Setoodeh, Aria; Saleh-Gohari, Nasrollah; Astuti, Dewi; Barrett, Timothy G

2013-03-01

Wolfram syndrome (WFS) is a neurodegenerative genetic condition characterized by juvenile-onset of diabetes mellitus and optic atrophy. We studied clinical features and the molecular basis of severe WFS (neurodegenerative complications) in two consanguineous families from Iran. A clinical and molecular genetic investigation was performed in the affected and healthy members of two families. The clinical diagnosis of WFS was confirmed by the existence of diabetes mellitus and optic atrophy in the affected patients, who in addition had severe neurodegenerative complications. Sequencing of WFS1 was undertaken in one affected member from each family. Targeted mutations were tested in all members of relevant families. Patients had most of the reported features of WFS. Two affected males in the first family had fathered unaffected children. We identified two homozygous mutations previously reported with apparently milder phenotypes: family 1: c.631G>A (p.Asp211Asn) in exon 5, and family 2: c.1456C>T (p.Gln486*) in exon 8. Heterozygous carriers were unaffected. This is the first report of male Wolfram patients who have successfully fathered children. Surprisingly, they also had almost all the complications associated with WFS. Our report has implications for genetic counseling and family planning advice for other affected families.

Adenovirus mediated homozygous endometrial epithelial Pten deletion results in aggressive endometrial carcinoma

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Joshi, Ayesha; Ellenson, Lora Hedrick, E-mail: lora.ellenson@med.cornell.edu

2011-07-01

Pten is the most frequently mutated gene in uterine endometriod carcinoma (UEC) and its precursor complex atypical hyperplasia (CAH). Because the mutation frequency is similar in CAH and UEC, Pten mutations are thought to occur relatively early in endometrial tumorigenesis. Previous work from our laboratory using the Pten{sup +/-} mouse model has demonstrated somatic inactivation of the wild type allele of Pten in both CAH and UEC. In the present study, we injected adenoviruses expressing Cre into the uterine lumen of adult Pten floxed mice in an attempt to somatically delete both alleles of Pten specifically in the endometrium. Our results demonstrate that biallelic inactivation of Pten results in an increased incidence of carcinoma as compared to the Pten{sup +/-} mouse model. In addition, the carcinomas were more aggressive with extension beyond the uterus into adjacent tissues and were associated with decreased expression of nuclear ER{alpha} as compared to associated CAH. Primary cultures of epithelial and stromal cells were prepared from uteri of Pten floxed mice and Pten was deleted in vitro using Cre expressing adenovirus. Pten deletion was evident in both the epithelial and stromal cells and the treatment of the primary cultures with estrogen had different effects on Akt activation as well as Cyclin D3 expression in the two purified components. This study demonstrates that somatic biallelic inactivation of Pten in endometrial epithelium in vivo results in an increased incidence and aggressiveness of endometrial carcinoma compared to mice carrying a germline deletion of one allele and provides an important in vivo and in vitro model system for understanding the genetic underpinnings of endometrial carcinoma.

Adenovirus mediated homozygous endometrial epithelial Pten deletion results in aggressive endometrial carcinoma

International Nuclear Information System (INIS)

Joshi, Ayesha; Ellenson, Lora Hedrick

2011-01-01

Pten is the most frequently mutated gene in uterine endometriod carcinoma (UEC) and its precursor complex atypical hyperplasia (CAH). Because the mutation frequency is similar in CAH and UEC, Pten mutations are thought to occur relatively early in endometrial tumorigenesis. Previous work from our laboratory using the Pten +/- mouse model has demonstrated somatic inactivation of the wild type allele of Pten in both CAH and UEC. In the present study, we injected adenoviruses expressing Cre into the uterine lumen of adult Pten floxed mice in an attempt to somatically delete both alleles of Pten specifically in the endometrium. Our results demonstrate that biallelic inactivation of Pten results in an increased incidence of carcinoma as compared to the Pten +/- mouse model. In addition, the carcinomas were more aggressive with extension beyond the uterus into adjacent tissues and were associated with decreased expression of nuclear ERα as compared to associated CAH. Primary cultures of epithelial and stromal cells were prepared from uteri of Pten floxed mice and Pten was deleted in vitro using Cre expressing adenovirus. Pten deletion was evident in both the epithelial and stromal cells and the treatment of the primary cultures with estrogen had different effects on Akt activation as well as Cyclin D3 expression in the two purified components. This study demonstrates that somatic biallelic inactivation of Pten in endometrial epithelium in vivo results in an increased incidence and aggressiveness of endometrial carcinoma compared to mice carrying a germline deletion of one allele and provides an important in vivo and in vitro model system for understanding the genetic underpinnings of endometrial carcinoma.

Methylenetetrahydrofolate reductase homozygous mutation in a young boy with cerebellar infarction

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Alberto Spalice

2009-11-01

Full Text Available Posterior circulation vascular occlusive disease in children is a rare and uncommonly reported event. Among the numerous risk factors, the methylenetetrahydrofolate reductase (MTHFR mutation is considered to be a common genetic cause of thrombosis in adults and children. Recently, a link between the MTHFR mutation and cerebrovascular disorders was reported in children. Diffusion tensor imaging (DTI is a great improvement on magnetic resonance imaging (MRI, making the in vivo anatomical and pathological study of the brain and its fibers possible. In our patient cerebellar infarction was associated with MTHFR mutation and, in a standard neurological examination, DTI revealed normal white matter tracts.

Portuguese family with the co-occurrence of frontotemporal lobar degeneration and neuronal ceroid lipofuscinosis phenotypes due to progranulin gene mutation.

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Almeida, Maria R; Macário, Maria C; Ramos, Lina; Baldeiras, Inês; Ribeiro, Maria H; Santana, Isabel

2016-05-01

We and others have reported heterozygous progranulin mutations as an important cause of frontotemporal lobar degeneration (FTLD). It has been identified a complete progranulin deficiency because of a homozygous mutation in a sibling pair with neuronal ceroid lipofuscinosis (NCL). Here, we describe the first case of NCL caused by a homozygous progranulin mutation segregating in a family with neuropathological confirmed FTLD. In this FTLD-NCL family, we detail the clinical phenotype, neuropsychological evaluation and imaging data of our proband harboring a homozygous mutation, c.900_901dupGT, with serum progranulin level (progranulin levels in suspected recessive adult-onset NCL cases. Overall, a more holistic neurologic intervention is needed to guarantee a proper genetic counseling in cases like the present family where two distinct phenotypes are generated according to the individuals' mutation state. Copyright © 2016 Elsevier Inc. All rights reserved.

Congenital Chloride-Losing Diarrhea in a Mexican child with the novel homozygous SLC26A3 mutation G393W

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Fabian R. Reimold

2015-06-01

Full Text Available Congenital chloride diarrhea is an autosomal recessive disease caused by mutations in the intestinal lumenal membrane Cl-/HCO3- exchanger, SLC26A3.We report here the novel SLC26A3 mutation G393W in a Mexican child, the first such report in a patient from Central America. SLC26A3 G393W expression in Xenopus oocytes exhibits a mild hypomorphic phenotype, with normal surface expression and moderately reduced anion transport function. However, expression of HA-SLC26A3 in HEK-293 cells reveals intracellular retention and greatly decreased steady-state levels of the mutant polypeptide, in contrast to peripheral membrane expression of the wildtype protein. Whereas wildtype HA-SLC26A3 is apically localized in polarized monolayers of filter-grown MDCK cells and Caco2 cells, mutant HA-SLC26A3 G393W exhibits decreased total polypeptide abundance, with reduced or absent surface expression and sparse punctate (or absent intracellular distribution. The WT protein is similarly localized in LLCPK1 cells, but the mutant fails to accumulate to detectable levels. We conclude that the chloride-losing diarrhea phenotype associated with homozygous expression of SLC26A3 G393W likely reflects lack of apical surface expression in enterocytes, secondary to combined abnormalities in polypeptide trafficking and stability. Future progress in development of general or target-specific folding chaperonins and correctors may hold promise for pharmacological rescue of this and similar genetic defects in membrane protein targeting.

Mutation screening of the HGD gene identifies a novel alkaptonuria mutation with significant founder effect and high prevalence.

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Sakthivel, Srinivasan; Zatkova, Andrea; Nemethova, Martina; Surovy, Milan; Kadasi, Ludevit; Saravanan, Madurai P

2014-05-01

Alkaptonuria (AKU) is an autosomal recessive disorder; caused by the mutations in the homogentisate 1, 2-dioxygenase (HGD) gene located on Chromosome 3q13.33. AKU is a rare disorder with an incidence of 1: 250,000 to 1: 1,000,000, but Slovakia and the Dominican Republic have a relatively higher incidence of 1: 19,000. Our study focused on studying the frequency of AKU and identification of HGD gene mutations in nomads. HGD gene sequencing was used to identify the mutations in alkaptonurics. For the past four years, from subjects suspected to be clinically affected, we found 16 positive cases among a randomly selected cohort of 41 Indian nomads (Narikuravar) settled in the specific area of Tamil Nadu, India. HGD gene mutation analysis showed that 11 of these patients carry the same homozygous splicing mutation c.87 + 1G > A; in five cases, this mutation was found to be heterozygous, while the second AKU-causing mutation was not identified in these patients. This result indicates that the founder effect and high degree of consanguineous marriages have contributed to AKU among nomads. Eleven positive samples were homozygous for a novel mutation c.87 + 1G > A, that abolishes an intron 2 donor splice site and most likely causes skipping of exon 2. The prevalence of AKU observed earlier seems to be highly increased in people of nomadic origin. © 2014 John Wiley & Sons Ltd/University College London.

STAT3 mutations correlated with hyper-IgE syndrome lead to ...

Indian Academy of Sciences (India)

Of all the causes identified for the disease hyper-immunoglobulinemia E syndrome (HIES), a homozygous mutation in tyrosine kinase2 (TYK2) and heterozygous mutations in STAT3 are implicated the defects in Jak/STAT signalling pathway in the pathogenesis of HIES. Mutations of STAT3 have been frequently clinically ...

Genetic and molecular analyses of UV radiation-induced mutations in the fem-3 gene of Caenorhabditis elegans

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Hartman, P S; De Wilde, D; Dwarakanath, V N [Texas Christian Univ., Fort Worth, TX (United States). Dept. of Biology

1995-06-01

The utility of a new target gene (fem-3) is described for investigating the molecular nature of mutagenesis in the nematode Caenorhabditis elegans. As a principal attribute, this system allows for the selection, maintenance and molecular analysis of any type of mutation that disrupts the gene, including deletions. In this study, 86 mutant strains were isolated, of which 79 proved to have mutations in fem-3. Twenty of these originally tested as homozygous inviable. Homozygous inviability was expected, as Stewart and coworkers had previously observed that, unlike in other organisms, most UV radiation-induced mutations in C. elegans are chromosomal rearrangements of deficiencies (Mutat. Res 249, 37-54, 1991). However, additional data, including Southern blot analyses on 49 of the strains, indicated that most of the UV radiation-induced fem-3 mutations were not deficiencies, as originally inferred from their homozygous inviability. Instead, the lethals were most likely ``coincident mutations`` in linked, essential genes that were concomitantly induced. As such, they were lost owing to genetic recombination during stock maintenance. As in mammalian cells, yeast and bacteria, the frequency of coincident mutations was much higher than would be predicted by chance. (Author).

NDST1 missense mutations in autosomal recessive intellectual disability.

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Reuter, Miriam S; Musante, Luciana; Hu, Hao; Diederich, Stefan; Sticht, Heinrich; Ekici, Arif B; Uebe, Steffen; Wienker, Thomas F; Bartsch, Oliver; Zechner, Ulrich; Oppitz, Cornelia; Keleman, Krystyna; Jamra, Rami Abou; Najmabadi, Hossein; Schweiger, Susann; Reis, André; Kahrizi, Kimia

2014-11-01

NDST1 was recently proposed as a candidate gene for autosomal recessive intellectual disability in two families. It encodes a bifunctional GlcNAc N-deacetylase/N-sulfotransferase with important functions in heparan sulfate biosynthesis. In mice, Ndst1 is crucial for embryonic development and homozygous null mutations are perinatally lethal. We now report on two additional unrelated families with homozygous missense NDST1 mutations. All mutations described to date predict the substitution of conserved amino acids in the sulfotransferase domain, and mutation modeling predicts drastic alterations in the local protein conformation. Comparing the four families, we noticed significant overlap in the clinical features, including both demonstrated and apparent intellectual disability, muscular hypotonia, epilepsy, and postnatal growth deficiency. Furthermore, in Drosophila, knockdown of sulfateless, the NDST ortholog, impairs long-term memory, highlighting its function in cognition. Our data confirm NDST1 mutations as a cause of autosomal recessive intellectual disability with a distinctive phenotype, and support an important function of NDST1 in human development. © 2014 Wiley Periodicals, Inc.

Highly prevalent LIPH founder mutations causing autosomal recessive woolly hair/hypotrichosis in Japan and the genotype/phenotype correlations.

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Kana Tanahashi

Full Text Available Mutations in LIPH cause of autosomal recessive woolly hair/hypotrichosis (ARWH, and the 2 missense mutations c.736T>A (p.Cys246Ser and c.742C>A (p.His248Asn are considered prevalent founder mutations for ARWH in the Japanese population. To reveal genotype/phenotype correlations in ARWH cases in Japan and the haplotypes in 14 Japanese patients from 14 unrelated Japanese families. 13 patients had woolly hair, and 1 patient had complete baldness since birth. An LIPH mutation search revealed homozygous c.736T>A mutations in 10 of the patients. Compound heterozygous c.736T>A and c.742C>A mutations were found in 3 of the patients, and homozygous c.742C>A mutation in 1 patient. The phenotype of mild hypotrichosis with woolly hair was restricted to the patients with the homozygous c.736T>A mutation. The severe phenotype of complete baldness was seen in only 1 patient with homozygous c.742C>A. Haplotype analysis revealed that the alleles containing the LIPH c.736T>A mutation had a haplotype identical to that reported previously, although 4 alleles out of 5 chromosomes containing the LIPH c.742C>A mutation had a different haplotype from the previously reported founder allele. These alleles with c.742C>A are thought to be the third founder LIPH mutation causing ARWH. To accurately determine the prevalence of the founder mutations, we investigated allele frequencies of those mutations in 819 Japanese controls. Heterozygous c.736T>A mutations were found in 13 controls (allele frequency: 0.0079; carrier rate: 0.016, and heterozygous c.742C>A mutations were found in 2 controls (allele frequency: 0.0012; carrier rate: 0.0024. In conclusion, this study confirms the more accurate allele frequencies of the pathogenic founder mutations of LIPH and shows that there is a third founder mutation in Japan. In addition, the present findings suggest that the mutation patterns of LIPH might be associated with hypotrichosis severity in ARWH.

Skewed X-inactivation in cloned mice

International Nuclear Information System (INIS)

Senda, Sho; Wakayama, Teruhiko; Yamazaki, Yukiko; Ohgane, Jun; Hattori, Naka; Tanaka, Satoshi; Yanagimachi, Ryuzo; Shiota, Kunio

2004-01-01

In female mammals, dosage compensation for X-linked genes is accomplished by inactivation of one of two X chromosomes. The X-inactivation ratio (a percentage of the cells with inactivated maternal X chromosomes in the whole cells) is skewed as a consequence of various genetic mutations, and has been observed in a number of X-linked disorders. We previously reported that phenotypically normal full-term cloned mouse fetuses had loci with inappropriate DNA methylation. Thus, cloned mice are excellent models to study abnormal epigenetic events in mammalian development. In the present study, we analyzed X-inactivation ratios in adult female cloned mice (B6C3F1). Kidneys of eight naturally produced controls and 11 cloned mice were analyzed. Although variations in X-inactivation ratio among the mice were observed in both groups, the distributions were significantly different (Ansary-Bradley test, P < 0.01). In particular, 2 of 11 cloned mice showed skewed X-inactivation ratios (19.2% and 86.8%). Similarly, in intestine, 1 of 10 cloned mice had a skewed ratio (75.7%). Skewed X-inactivation was observed to various degrees in different tissues of different individuals, suggesting that skewed X-inactivation in cloned mice is the result of secondary cell selection in combination with stochastic distortion of primary choice. The present study is the first demonstration that skewed X-inactivation occurs in cloned animals. This finding is important for understanding both nuclear transfer technology and etiology of X-linked disorders

Molecular analysis of congenital goitres with hypothyroidism caused by defective thyroglobulin synthesis. Identification of a novel c.7006C>T [p.R2317X] mutation and expression of minigenes containing nonsense mutations in exon 7.

Science.gov (United States)

Machiavelli, Gloria A; Caputo, Mariela; Rivolta, Carina M; Olcese, María C; Gruñeiro-Papendieck, Laura; Chiesa, Ana; González-Sarmiento, Rogelio; Targovnik, Héctor M

2010-01-01

Thyroglobulin (TG) deficiency is an autosomal-recessive disorder that results in thyroid dyshormonogenesis. A number of distinct mutations have been identified as causing human hypothyroid goitre. The purpose of this study was to identify and characterize new mutations in the TG gene in an attempt to increase the understanding of the genetic mechanism responsible for this disorder. A total of six patients from four nonconsanguineous families with marked impairment of TG synthesis were studied. Single-strand conformation polymorphism (SSCP) analysis, sequencing of DNA, genotyping, expression of chimeric minigenes and bioinformatic analysis were performed. Four different inactivating TG mutations were identified: one novel mutation (c.7006C>T [p.R2317X]) and three previously reported (c.886C>T [p.R277X], c.6701C>A [p.A2215D] and c.6725G>A [p.R2223H]). Consequently, one patient carried a compound heterozygous for p.R2223H/p.R2317X mutations; two brothers showed a homozygous p.A2215D substitution and the remaining three patients, from two families with typical phenotype, had a single p.R277X mutated allele. We also showed functional evidences that premature stop codons inserted at different positions in exon 7, which disrupt exonic splicing enhancer (ESE) sequences, do not interfere with exon definition and processing. In this study, we have identified a novel nonsense mutation p.R2317X in the acetylcholinesterase homology domain of TG. We have also observed that nonsense mutations do not interfere with the pre-mRNA splicing of exon 7. The results are in accordance with previous observations confirming the genetic heterogeneity of TG defects.

Evaluation of Lama5 as a candidate for the mouse ragged (Ra) mutation

DEFF Research Database (Denmark)

Durkin, M E; Albrechtsen, R; Chambers, D M

1998-01-01

The laminin alpha5 chain is a component of the basement membranes of many developing and adult tissues. The mouse laminin alpha5 chain gene (Lama5) has been mapped close to the locus of the semidominant ragged (Ra) mutation on distal chromosome 2. The cause of the Ra mutation, which is usually...... lethal in the homozygous state, has not been determined. We have investigated whether a defect in Lama5 is responsible for the ragged mutation, using the RaJ strain. No differences in the level of the laminin alpha5 chain transcript were found in placental RNA from homozygous RaJ mutant embryos compared...... to normal littermates. Antiserum raised against a recombinant laminin alpha5 chain polypeptide stained the basement membranes of both normal and homozygous mutant embryos to a similar extent. More precise mapping of Lama5 on an interspecific Ra backcross indicated that Lama5 is proximal to the Ra locus...

Laser desorption mass spectrometry for point mutation detection

Energy Technology Data Exchange (ETDEWEB)

Taranenko, N.I.; Chung, C.N.; Zhu, Y.F. [Oak Ridge National Lab., TN (United States)] [and others

1996-12-31

A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments by digestion of a PCR generated target fragment. 21 refs., 10 figs., 2 tabs.

High resolution melting for mutation scanning of TP53 exons 5–8

International Nuclear Information System (INIS)

Krypuy, Michael; Dobrovic, Alexander; Ahmed, Ahmed Ashour; Etemadmoghadam, Dariush; Hyland, Sarah J; Australian Ovarian Cancer Study Group; Fazio, Anna de; Fox, Stephen B; Brenton, James D; Bowtell, David D

2007-01-01

p53 is commonly inactivated by mutations in the DNA-binding domain in a wide range of cancers. As mutant p53 often influences response to therapy, effective and rapid methods to scan for mutations in TP53 are likely to be of clinical value. We therefore evaluated the use of high resolution melting (HRM) as a rapid mutation scanning tool for TP53 in tumour samples. We designed PCR amplicons for HRM mutation scanning of TP53 exons 5 to 8 and tested them with DNA from cell lines hemizygous or homozygous for known mutations. We assessed the sensitivity of each PCR amplicon using dilutions of cell line DNA in normal wild-type DNA. We then performed a blinded assessment on ovarian tumour DNA samples that had been previously sequenced for mutations in TP53 to assess the sensitivity and positive predictive value of the HRM technique. We also performed HRM analysis on breast tumour DNA samples with unknown TP53 mutation status. One cell line mutation was not readily observed when exon 5 was amplified. As exon 5 contained multiple melting domains, we divided the exon into two amplicons for further screening. Sequence changes were also introduced into some of the primers to improve the melting characteristics of the amplicon. Aberrant HRM curves indicative of TP53 mutations were observed for each of the samples in the ovarian tumour DNA panel. Comparison of the HRM results with the sequencing results revealed that each mutation was detected by HRM in the correct exon. For the breast tumour panel, we detected seven aberrant melt profiles by HRM and subsequent sequencing confirmed the presence of these and no other mutations in the predicted exons. HRM is an effective technique for simple and rapid scanning of TP53 mutations that can markedly reduce the amount of sequencing required in mutational studies of TP53

Isogenic transgenic homozygous fish induced by artificial parthenogenesis.

Science.gov (United States)

Nam, Y K; Cho, Y S; Kim, D S

2000-12-01

As a model system for vertebrate transgenesis, fish have many attractive advantages, especially with respect to the characteristics of eggs, allowing us to produce isogenic, transgenic, homozygous vertebrates by combining with chromosome-set manipulation. Here, we describe the large-scale production of isogenic transgenic homozygous animals using our experimental organism, the mud loach Misgurnus mizolepis, by the simple process of artificial parthenogenesis in a single generation. These isogenic fish have retained transgenic homozygous status in a stable manner during the subsequent 5 years, and exhibited increased levels of transgene expression. Furthermore, their isogenic nature was confirmed by cloned transgenic homozygous offspring produced via another step of parthenogenic reproduction of the isogenic homozygous transgenic fish. These results demonstrate that a combination of transgenesis and artificial parthenogenesis will make the rapid utilization of genetically pure homozygous transgenic system in vertebrate transgenesis possible.

Inactivation of the Sema5a gene results in embryonic lethality and defective remodeling of the cranial vascular system

NARCIS (Netherlands)

Fiore, Roberto; Rahim, Belquis; Christoffels, Vincent M.; Moorman, Antoon F. M.; Püschel, Andreas W.

2005-01-01

The semaphorins are a large family of proteins involved in the patterning of both the vascular and the nervous systems. In order to analyze the function of the membrane-bound semaphorin 5A (Sema5A), we generated mice homozygous for a null mutation in the Sema5a gene. Homozygous null mutants die

Mitochondrial DNA mutations in mutator mice confer respiration defects and B-cell lymphoma development.

Directory of Open Access Journals (Sweden)

Takayuki Mito

Full Text Available Mitochondrial DNA (mtDNA mutator mice are proposed to express premature aging phenotypes including kyphosis and hair loss (alopecia due to their carrying a nuclear-encoded mtDNA polymerase with a defective proofreading function, which causes accelerated accumulation of random mutations in mtDNA, resulting in expression of respiration defects. On the contrary, transmitochondrial mito-miceΔ carrying mtDNA with a large-scale deletion mutation (ΔmtDNA also express respiration defects, but not express premature aging phenotypes. Here, we resolved this discrepancy by generating mtDNA mutator mice sharing the same C57BL/6J (B6J nuclear background with that of mito-miceΔ. Expression patterns of premature aging phenotypes are very close, when we compared between homozygous mtDNA mutator mice carrying a B6J nuclear background and selected mito-miceΔ only carrying predominant amounts of ΔmtDNA, in their expression of significant respiration defects, kyphosis, and a short lifespan, but not the alopecia. Therefore, the apparent discrepancy in the presence and absence of premature aging phenotypes in mtDNA mutator mice and mito-miceΔ, respectively, is partly the result of differences in the nuclear background of mtDNA mutator mice and of the broad range of ΔmtDNA proportions of mito-miceΔ used in previous studies. We also provided direct evidence that mtDNA abnormalities in homozygous mtDNA mutator mice are responsible for respiration defects by demonstrating the co-transfer of mtDNA and respiration defects from mtDNA mutator mice into mtDNA-less (ρ(0 mouse cells. Moreover, heterozygous mtDNA mutator mice had a normal lifespan, but frequently developed B-cell lymphoma, suggesting that the mtDNA abnormalities in heterozygous mutator mice are not sufficient to induce a short lifespan and aging phenotypes, but are able to contribute to the B-cell lymphoma development during their prolonged lifespan.

Mitochondrial leukoencephalopathy and complex II deficiency associated with a recessive SDHB mutation with reduced penetrance

Directory of Open Access Journals (Sweden)

Anna Ardissone

2015-12-01

Full Text Available Mitochondrial disease involving complex II is rare among respiratory chain deficiencies and its genetic cause remains often unknown. Two main clinical presentations are associated with this biochemical defect: mitochondrial encephalomyopathy and susceptibility to tumors. Only one homozygous SDHB mutation has been described in a patient with mitochondrial disorder. We report here two sisters, who presented highly different phenotypes (neurological impairment with leukoencephalopathy vs. asymptomatic status and harbored the same homozygous SDHB mutation, suggesting reduced penetrance.

Mutations in PCBD1 Cause Hypomagnesemia and Renal Magnesium Wasting

NARCIS (Netherlands)

Ferre, S.; Baaij, J.H.F. de; Ferreira, P.; Germann, R.; Klerk, J.B. De; Lavrijsen, M.; Zeeland, F. van; Venselaar, H.; Kluijtmans, L.A.; Hoenderop, J.G.J.; Bindels, R.J.M.

2014-01-01

Mutations in PCBD1 are causative for transient neonatal hyperphenylalaninemia and primapterinuria (HPABH4D). Until now, HPABH4D has been regarded as a transient and benign neonatal syndrome without complications in adulthood. In our study of three adult patients with homozygous mutations in the

[The audiological analysis in the patients homozygous for the c.-23+1G>A mutation in the GJB2 gene presenting with the loss of hearing in Yakutiya].

Science.gov (United States)

Teryutin, F M; Barashkov, N A; Kunel'skaya, N L; Pshennikova, V G; Solov'ev, A V

2016-01-01

In the course of previous investigations carried out in the Republic of Sakha (Yakutiya), we have identified the main molecular-genetic factor responsible for the hereditary impairment of hearing among the indigenous population (mostly the Yakuts).The disease was shown to be attributable to the c.-23+1G>A mutation localized in the splice donor site (exon 1) of the GJB2 (Cx26) gene. The present study involved the comprehensive audiological analysis of the patients homozygous for the c.-23+1G>A mutation in the GJB2 gene based on the results of the study of a large sample of the patients residing in Yakutiya. All individuals with the GJB2 genotype c.-23+1G>A/c.-23-1G>A (n=108) at the mean age of 14.32±4.7 years (all ethnic Yakuts)were examined with the use oftonal threshold audiometry for air conduction testing at the frequencies of 0.25, 0.5, 1.0, 2.0, 4.0, and 8.0 kHz and bone conduction testing at the frequencies of 0.25, 0.5, 1.0, and 4.0 with a step of 5.0 dB.The results of the ASSR test were used whenever tonal threshold audiometry proved impracticable The data obtained in the study characterize the allelic form of the disease associated with the GJB2 genotype c.-23+1G>A/c.-23-1G>A as the congenital bilateral symmetric (90.1%), sensorineural (90.1%) form of hearing impairment of variable severity (from grade 1 to complete deafness) with the «flat» audiological profile (median slope not more than 5.0 dB in the extended frequency range (EFR) of 0.5, 1.0, 2.0, and 4.0, kHz). It is concluded that the results of the audiological analysis performed in the present study give evidence of relatively homogeneous but variable in terms of severity impairment of hearing in the patients homozygous for the c.-23+1G>A mutation in the GJB2 (Cx26) gene. It may serve as a positive prognostic sign to be used in the development and prescription of hearing aids.

Genetic inactivation of the Fanconi anemia gene FANCC identified in the hepatocellular carcinoma cell line HuH-7 confers sensitivity towards DNA-interstrand crosslinking agents

Directory of Open Access Journals (Sweden)

Bassermann Florian

2010-05-01

Full Text Available Abstract Background Inactivation of the Fanconi anemia (FA pathway through defects in one of 13 FA genes occurs at low frequency in various solid cancer entities among the general population. As FA pathway inactivation confers a distinct hypersensitivity towards DNA interstrand-crosslinking (ICL-agents, FA defects represent rational targets for individualized therapeutic strategies. Except for pancreatic cancer, however, the prevalence of FA defects in gastrointestinal (GI tumors has not yet been systematically explored. Results A panel of GI cancer cell lines was screened for FA pathway inactivation applying FANCD2 monoubiquitination and FANCD2/RAD51 nuclear focus formation and a newly identified FA pathway-deficient cell line was functionally characterized. The hepatocellular carcinoma (HCC line HuH-7 was defective in FANCD2 monoubiquitination and FANCD2 nuclear focus formation but proficient in RAD51 focus formation. Gene complementation studies revealed that this proximal FA pathway inactivation was attributable to defective FANCC function in HuH-7 cells. Accordingly, a homozygous inactivating FANCC nonsense mutation (c.553C > T, p.R185X was identified in HuH-7, resulting in partial transcriptional skipping of exon 6 and leading to the classic cellular FA hypersensitivity phenotype; HuH-7 cells exhibited a strongly reduced proliferation rate and a pronounced G2 cell cycle arrest at distinctly lower concentrations of ICL-agents than a panel of non-isogenic, FA pathway-proficient HCC cell lines. Upon retroviral transduction of HuH-7 cells with FANCC cDNA, FA pathway functions were restored and ICL-hypersensitivity abrogated. Analyses of 18 surgical HCC specimens yielded no further examples for genetic or epigenetic inactivation of FANCC, FANCF, or FANCG in HCC, suggesting a low prevalence of proximal FA pathway inactivation in this tumor type. Conclusions As the majority of HCC are chemoresistant, assessment of FA pathway function in HCC could

Laser desorption mass spectrometry for point mutation detection

Energy Technology Data Exchange (ETDEWEB)

Taranenko, N.I.; Chung, C.N.; Zhu, Y.F. [Oak Ridge National Lab., TN (United States)] [and others

1996-10-01

A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments generated by digestion of a PCR generated target fragment. 21 refs., 10 figs., 2 tabs.

Genetic heterogeneity and consanguinity lead to a "double hit": homozygous mutations of MYO7A and PDE6B in a patient with retinitis pigmentosa.

Science.gov (United States)

Goldenberg-Cohen, Nitza; Banin, Eyal; Zalzstein, Yael; Cohen, Ben; Rotenstreich, Ygal; Rizel, Leah; Basel-Vanagaite, Lina; Ben-Yosef, Tamar

2013-01-01

Retinitis pigmentosa (RP), the most genetically heterogeneous disorder in humans, actually represents a group of pigmentary retinopathies characterized by night blindness followed by visual-field loss. RP can appear as either syndromic or nonsyndromic. One of the most common forms of syndromic RP is Usher syndrome, characterized by the combination of RP, hearing loss, and vestibular dysfunction. The underlying cause of the appearance of syndromic and nonsyndromic RP in three siblings from a consanguineous Israeli Muslim Arab family was studied with whole-genome homozygosity mapping followed by whole exome sequencing. THE FAMILY WAS FOUND TO SEGREGATE NOVEL MUTATIONS OF TWO DIFFERENT GENES: myosin VIIA (MYO7A), which causes type 1 Usher syndrome, and phosphodiesterase 6B, cyclic guanosine monophosphate-specific, rod, beta (PDE6B), which causes nonsyndromic RP. One affected child was homozygous for both mutations. Since the retinal phenotype seen in this patient results from overlapping pathologies, one might expect to find severe retinal degeneration. Indeed, he was diagnosed with RP based on an abnormal electroretinogram (ERG) at a young age (9 months). However, this early diagnosis may be biased, as two of his older siblings had already been diagnosed, leading to increased awareness. At the age of 32 months, he had relatively good vision with normal visual fields. Further testing of visual function and structure at different ages in the three siblings is needed to determine whether the two RP-causing genes mutated in this youngest sibling confer increased disease severity. This report further supports the genetic heterogeneity of RP, and demonstrates how consanguinity could increase intrafamilial clustering of multiple hereditary diseases. Moreover, this report provides a unique opportunity to study the clinical implications of the coexistence of pathogenic mutations in two RP-causative genes in a human patient.

Expanding the clinical and molecular spectrum of PRMT7 mutations: 3 additional patients and review.

Science.gov (United States)

Agolini, E; Dentici, M L; Bellacchio, E; Alesi, V; Radio, F C; Torella, A; Musacchia, F; Tartaglia, M; Dallapiccola, B; Nigro, V; Digilio, M C; Novelli, A

2018-03-01

Protein arginine methyltransferase 7 (PRMT7) is a member of a family of enzymes that catalyze the transfer of methyl groups from S-adenosyl-l-methionine to nitrogen atoms on arginine residues. Arginine methylation is involved in multiple biological processes, such as signal transduction, mRNA splicing, transcriptional control, DNA repair, and protein translocation. Currently, 7 patients have been described harboring compound heterozygous or homozygous variants in the PRMT7 gene, causing a novel intellectual disability syndrome, known as SBIDDS syndrome (Short Stature, Brachydactyly, Intellectual Developmental Disability, and Seizures). We report on 3 additional patients from 2 consanguineous families with severe/moderate intellectual disability, short stature, brachydactyly and dysmorphisms. Exome sequencing revealed 2 novel homozygous mutations in PRMT7. Our findings expand the clinical and molecular spectrum of homozygous PRMT7 mutations, associated to the SBIDDS syndrome, showing a possible correlation between the type of mutation and the severity of the phenotype. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Homozygous variegate porphyria presenting with developmental and language delay in childhood.

Science.gov (United States)

Pinder, V A E; Holden, S T; Deshpande, C; Siddiqui, A; Mellerio, J E; Wraige, E; Powell, A M

2013-10-01

Variegate porphyria is an autosomal dominant disorder that usually presents with photosensitivity and acute neurological crises in adulthood. It is caused by heterozygous mutations in the protoporphyrinogen oxidase gene (PPOX). A rarer variant, homozygous variegate porphyria (HVP), presents in childhood with recurrent skin blisters and scarring. More variable features of HVP are short stature, brachydactyly, nystagmus, epilepsy, developmental delay and mental retardation. We describe a child who presented with nystagmus, developmental delay and ataxia, combined with a photosensitive eruption. Analysis of porphyrins in plasma, urine and stool supported a clinical diagnosis of HVP. DNA from the patient showed that he is compound heterozygous for two novel missense mutations in the PPOX coding region: c.169G>C (p.Gly57Arg) and c.1259C>G (Pro420Arg). Interestingly, cranial magnetic resonance imaging showed an absence of myelin, a feature not previously reported in HVP, which expands the differential diagnosis of childhood hypomyelinating leucoencephalopathies. © 2013 British Association of Dermatologists.

Tezacaftor-Ivacaftor in Patients with Cystic Fibrosis Homozygous for Phe508del.

Science.gov (United States)

Taylor-Cousar, Jennifer L; Munck, Anne; McKone, Edward F; van der Ent, Cornelis K; Moeller, Alexander; Simard, Christopher; Wang, Linda T; Ingenito, Edward P; McKee, Charlotte; Lu, Yimeng; Lekstrom-Himes, Julie; Elborn, J Stuart

2017-11-23

Combination treatment with the cystic fibrosis transmembrane conductance regulator (CFTR) modulators tezacaftor (VX-661) and ivacaftor (VX-770) was designed to target the underlying cause of disease in patients with cystic fibrosis. In this phase 3, randomized, double-blind, multicenter, placebo-controlled, parallel-group trial, we evaluated combination therapy with tezacaftor and ivacaftor in patients 12 years of age or older who had cystic fibrosis and were homozygous for the CFTR Phe508del mutation. Patients were randomly assigned in a 1:1 ratio to receive either 100 mg of tezacaftor once daily and 150 mg of ivacaftor twice daily or matched placebo for 24 weeks. The primary end point was the absolute change in the percentage of the predicted forced expiratory volume in 1 second (FEV 1 ) through week 24 (calculated in percentage points); relative change in the percentage of the predicted FEV 1 through week 24 (calculated as a percentage) was a key secondary end point. Of the 510 patients who underwent randomization, 509 received tezacaftor-ivacaftor or placebo, and 475 completed 24 weeks of the trial regimen. The mean FEV 1 at baseline was 60.0% of the predicted value. The effects on the absolute and relative changes in the percentage of the predicted FEV 1 in favor of tezacaftor-ivacaftor over placebo were 4.0 percentage points and 6.8%, respectively (Pcystic fibrosis and were homozygous for the CFTR Phe508del mutation. (Funded by Vertex Pharmaceuticals; EVOLVE ClinicalTrials.gov number, NCT02347657 .).

Presentation of Complex Homozygous Allele in ABCA4 Gene in a Patient with Retinitis Pigmentosa

Directory of Open Access Journals (Sweden)

Māreta Audere

2015-01-01

Full Text Available Retinitis pigmentosa is a degenerative retinal disease characterized by progressive photoreceptor damage, which causes loss of peripheral and night vision and the development of tunnel vision and may result in loss of central vision. This study describes a patient with retinitis pigmentosa caused by a mutation in the ABCA4 gene with complex allele c.1622T>C, p.L541P; c.3113C>T, p.A1038V in homozygous state.

574-586 Mutations in PCBD1 cause hypomagnesemia and renal magnesium wasting

NARCIS (Netherlands)

S. Ferrè (Silvia); J.H.F. de Baaij (Jeroen); P. Ferreira (Patrick); R. Germann (Roger); J.B.C. de Klerk (Johannes); A.P.M. Lavrijsen (Adriana); F. van Zeeland (Femke); H. Venselaar (Hanka); L.A.J. Kluijtmans (Leo A.); J.G. Hoenderop (Joost); R.J.M. Bindels (René)

2014-01-01

textabstractMutations in PCBD1 are causative for transient neonatal hyperphenylalaninemia and primapterinuria (HPABH4D). Until now, HPABH4D has been regarded as a transient and benign neonatal syndrome without complications in adulthood. In our study of three adult patients with homozygous mutations

Tumor suppressor genes that escape from X-inactivation contribute to cancer sex bias

Science.gov (United States)

Dunford, Andrew; Weinstock, David M.; Savova, Virginia; Schumacher, Steven E.; Cleary, John P.; Yoda, Akinori; Sullivan, Timothy J.; Hess, Julian M.; Gimelbrant, Alexander A.; Beroukhim, Rameen; Lawrence, Michael S.; Getz, Gad; Lane, Andrew A.

2016-01-01

There is a striking and unexplained male predominance across many cancer types. A subset of X chromosome (chrX) genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative “Escape from X-Inactivation Tumor Suppressor” (EXITS) genes, we compared somatic alterations from >4100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) chrX genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) more frequently harbored loss-of-function mutations in males (based on false discovery rate <0.1), compared to zero of 18,055 autosomal and PAR genes (P<0.0001). Male-biased mutations in genes that escape X-inactivation were observed in combined analysis across many cancers and in several individual tumor types, suggesting a generalized phenomenon. We conclude that biallelic expression of EXITS genes in females explains a portion of the reduced cancer incidence compared to males across a variety of tumor types. PMID:27869828

Tumor-suppressor genes that escape from X-inactivation contribute to cancer sex bias.

Science.gov (United States)

Dunford, Andrew; Weinstock, David M; Savova, Virginia; Schumacher, Steven E; Cleary, John P; Yoda, Akinori; Sullivan, Timothy J; Hess, Julian M; Gimelbrant, Alexander A; Beroukhim, Rameen; Lawrence, Michael S; Getz, Gad; Lane, Andrew A

2017-01-01

There is a striking and unexplained male predominance across many cancer types. A subset of X-chromosome genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative 'escape from X-inactivation tumor-suppressor' (EXITS) genes, we examined somatic alterations from >4,100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) X-chromosome genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) harbored loss-of-function mutations more frequently in males (based on a false discovery rate < 0.1), in comparison to zero of 18,055 autosomal and PAR genes (Fisher's exact P < 0.0001). Male-biased mutations in genes that escape X-inactivation were observed in combined analysis across many cancers and in several individual tumor types, suggesting a generalized phenomenon. We conclude that biallelic expression of EXITS genes in females explains a portion of the reduced cancer incidence in females as compared to males across a variety of tumor types.

Genetic heterogeneity and consanguinity lead to a “double hit”: Homozygous mutations of MYO7A and PDE6B in a patient with retinitis pigmentosa

Science.gov (United States)

Goldenberg-Cohen, Nitza; Banin, Eyal; Zalzstein, Yael; Cohen, Ben; Rotenstreich, Ygal; Rizel, Leah; Basel-Vanagaite, Lina

2013-01-01

Purpose Retinitis pigmentosa (RP), the most genetically heterogeneous disorder in humans, actually represents a group of pigmentary retinopathies characterized by night blindness followed by visual-field loss. RP can appear as either syndromic or nonsyndromic. One of the most common forms of syndromic RP is Usher syndrome, characterized by the combination of RP, hearing loss, and vestibular dysfunction. Methods The underlying cause of the appearance of syndromic and nonsyndromic RP in three siblings from a consanguineous Israeli Muslim Arab family was studied with whole-genome homozygosity mapping followed by whole exome sequencing. Results The family was found to segregate novel mutations of two different genes: myosin VIIA (MYO7A), which causes type 1 Usher syndrome, and phosphodiesterase 6B, cyclic guanosine monophosphate-specific, rod, beta (PDE6B), which causes nonsyndromic RP. One affected child was homozygous for both mutations. Since the retinal phenotype seen in this patient results from overlapping pathologies, one might expect to find severe retinal degeneration. Indeed, he was diagnosed with RP based on an abnormal electroretinogram (ERG) at a young age (9 months). However, this early diagnosis may be biased, as two of his older siblings had already been diagnosed, leading to increased awareness. At the age of 32 months, he had relatively good vision with normal visual fields. Further testing of visual function and structure at different ages in the three siblings is needed to determine whether the two RP-causing genes mutated in this youngest sibling confer increased disease severity. Conclusions This report further supports the genetic heterogeneity of RP, and demonstrates how consanguinity could increase intrafamilial clustering of multiple hereditary diseases. Moreover, this report provides a unique opportunity to study the clinical implications of the coexistence of pathogenic mutations in two RP-causative genes in a human patient. PMID:23882135

APOA5 Q97X Mutation Identified through homozygosity mapping causes severe hypertriglyceridemia in a Chilean consanguineous family

Directory of Open Access Journals (Sweden)

Dussaillant Catalina

2012-11-01

Full Text Available Abstract Background Severe hypertriglyceridemia (HTG has been linked to defects in LPL, APOC2, APOA5, LMF1 and GBIHBP1 genes. However, a number of severe HTG cases are probably caused by as yet unidentified mutations. Very high triglyceride plasma levels (>112 mmol/L at diagnosis were found in two sisters of a Chilean consanguineous family, which is strongly suggestive of a recessive highly penetrant mutation. The aim of this study was to determine the genetic locus responsible for the severe HTG in this family. Methods We carried out a genome-wide linkage study with nearly 300,000 biallelic markers (Illumina Human CytoSNP-12 panel. Using the homozygosity mapping strategy, we searched for chromosome regions with excess of homozygous genotypes in the affected cases compared to non-affected relatives. Results A large homozygous segment was found in the long arm of chromosome 11, with more than 2,500 consecutive homozygous SNP shared by the proband with her affected sister, and containing the APOA5/A4/C3/A1 cluster. Direct sequencing of the APOA5 gene revealed a known homozygous nonsense Q97X mutation (p.Gln97Ter found in both affected sisters but not in non-affected relatives nor in a sample of unrelated controls. Conclusion The Q97X mutation of the APOA5 gene in homozygous status is responsible for the severe hypertriglyceridemia in this family. We have shown that homozygosity mapping correctly pinpointed the genomic region containing the gene responsible for severe hypertriglyceridemia in this consanguineous Chilean family.

APOA5 Q97X mutation identified through homozygosity mapping causes severe hypertriglyceridemia in a Chilean consanguineous family.

Science.gov (United States)

Dussaillant, Catalina; Serrano, Valentina; Maiz, Alberto; Eyheramendy, Susana; Cataldo, Luis Rodrigo; Chavez, Matías; Smalley, Susan V; Fuentes, Marcela; Rigotti, Attilio; Rubio, Lorena; Lagos, Carlos F; Martinez, José Alfredo; Santos, José Luis

2012-11-15

Severe hypertriglyceridemia (HTG) has been linked to defects in LPL, APOC2, APOA5, LMF1 and GBIHBP1 genes. However, a number of severe HTG cases are probably caused by as yet unidentified mutations. Very high triglyceride plasma levels (>112 mmol/L at diagnosis) were found in two sisters of a Chilean consanguineous family, which is strongly suggestive of a recessive highly penetrant mutation. The aim of this study was to determine the genetic locus responsible for the severe HTG in this family. We carried out a genome-wide linkage study with nearly 300,000 biallelic markers (Illumina Human CytoSNP-12 panel). Using the homozygosity mapping strategy, we searched for chromosome regions with excess of homozygous genotypes in the affected cases compared to non-affected relatives. A large homozygous segment was found in the long arm of chromosome 11, with more than 2,500 consecutive homozygous SNP shared by the proband with her affected sister, and containing the APOA5/A4/C3/A1 cluster. Direct sequencing of the APOA5 gene revealed a known homozygous nonsense Q97X mutation (p.Gln97Ter) found in both affected sisters but not in non-affected relatives nor in a sample of unrelated controls. The Q97X mutation of the APOA5 gene in homozygous status is responsible for the severe hypertriglyceridemia in this family. We have shown that homozygosity mapping correctly pinpointed the genomic region containing the gene responsible for severe hypertriglyceridemia in this consanguineous Chilean family.

Simplifying the detection of MUTYH mutations by high resolution melting analysis

International Nuclear Information System (INIS)

López-Villar, Isabel; Martínez-López, Joaquín; Ayala, Rosa; Wesselink, Jan; Morillas, Juan Diego; López, Elena; Marín, José Carlos; Díaz-Tasende, José; González, Sara; Robles, Luis

2010-01-01

MUTYH-associated polyposis (MAP) is a disorder caused by bi-allelic germline MUTYH mutation, characterized by multiple colorectal adenomas. In order to identify mutations in MUTYH gene we applied High Resolution Melting (HRM) genotyping. HRM analysis is extensively employed as a scanning method for the detection of heterozygous mutations. Therefore, we applied HRM to show effectiveness in detecting homozygous mutations for these clinically important and frequent patients. In this study, we analyzed phenotype and genotype data from 82 patients, with multiple (>= 10) synchronous (19/82) or metachronous (63/82) adenomas and negative APC study (except one case). Analysis was performed by HRM-PCR and direct sequencing, in order to identify mutations in MUTYH exons 7, 12 and 13, where the most prevalent mutations are located. In monoallelic mutation carriers, we evaluated entire MUTYH gene in search of another possible alteration. HRM-PCR was performed with strict conditions in several rounds: the first one to discriminate the heteroduplex patterns and homoduplex patterns and the next ones, in order to refine and confirm parameters. The genotypes obtained were correlated to phenotypic features (number of adenomas (synchronous or metachronous), colorectal cancer (CRC) and family history). MUTYH germline mutations were found in 15.8% (13/82) of patients. The hot spots, Y179C (exon 7) and G396D (exon 13), were readily identified and other mutations were also detected. Each mutation had a reproducible melting profile by HRM, both heterozygous mutations and homozygous mutations. In our study of 82 patients, biallelic mutation is associated with being a carrier of ≥10 synchronous polyps (p = 0.05) and there is no association between biallelic mutation and CRC (p = 0.39) nor family history (p = 0.63). G338H non-pathogenic polymorphism (exon 12) was found in 23.1% (19/82) of patients. In all cases there was concordance between HRM (first and subsequent rounds) and sequencing

SMARCA4 inactivating mutations cause concomitant Coffin–Siris syndrome, microphthalmia and small‐cell carcinoma of the ovary hypercalcaemic type

Science.gov (United States)

Mustafa, Noor; Vetro, Annalisa; Notarangelo, Lucia Dora; de Jonge, Hugo; Rinaldi, Berardo; Vergani, Debora; Giglio, Sabrina Rita; Morbini, Patrizia; Zuffardi, Orsetta

2017-01-01

Abstract SMARCA4 chromatin remodelling factor is mutated in 11% of Coffin–Siris syndrome (CSS) patients and in almost all small‐cell carcinoma of the ovary hypercalcaemic type (SCCOHT) tumours. Missense mutations with gain‐of‐function or dominant‐negative effects are associated with CSS, whereas inactivating mutations, leading to loss of SMARCA4 expression, have been exclusively found in SCCOHT. We applied whole‐exome sequencing to study a 15‐year‐old patient with mild CSS who concomitantly developed SCCOHT at age 13 years. Interestingly, our patient also showed congenital microphthalmia, which has never previously been reported in CSS patients. We detected a de novo germline heterozygous nonsense mutation in exon 19 of SMARCA4 (c.2935C > T;p.Arg979*), and a somatic frameshift mutation in exon 6 (c.1236_1236delC;p.Gln413Argfs*88), causing complete loss of SMARCA4 immunostaining in the tumour. The immunohistochemical findings are supported by the observation that the c.2935C > T mutant transcript was detected by reverse transcription polymerase chain reaction at a much lower level than the wild‐type allele in whole blood and the lymphoblastoid cell line of the proband, confirming nonsense‐mediated mRNA decay. Accordingly, immunoblotting demonstrated that there was approximately half the amount of SMARCA4 protein in the proband's cells as in controls. This study suggests that SMARCA4 constitutional mutations associated with CSS are not necessarily non‐truncating, and that haploinsufficiency may explain milder CSS phenotypes, as previously reported for haploinsufficient ARID1B. In addition, our case supports the dual role of chromatin remodellers in developmental disorders and cancer, as well as the involvement of SMARCA4 in microphthalmia, confirming previous findings in mouse models and the DECIPHER database. Finally, we speculate that mild CSS might be under‐recognized in a proportion of SCCOHT patients harbouring SMARCA4 mutations

XPC gene mutations in families with xeroderma pigmentosum from Pakistan; prevalent founder effect.

Science.gov (United States)

Ijaz, Ambreen; Basit, Sulman; Gul, Ajab; Batool, Lilas; Hussain, Abrar; Afzal, Sibtain; Ramzan, Khushnooda; Ahmad, Jamil; Wali, Abdul

2018-03-23

Xeroderma pigmentosum (XP) is a rare autosomal recessive skin disorder characterized by hyperpigmentation, premature skin aging, ocular and cutaneous photosensitivity, and increased risk of skin carcinoma. We investigated seven consanguineous XP families with nine patients from Pakistan. All the Patients exhibited typical clinical symptoms of XP since first year of life. Whole genome SNP genotyping identified a 14 Mb autozygous region segregating with the disease phenotype on chromosome 3p25.1. DNA sequencing of XPC gene revealed a founder homozygous splice site mutation (c.2251-1G>C) in patients from six families (A-F) and a homozygous nonsense mutation (c.1399C>T; p.Gln467*) in patients of family G. This is the first report of XPC mutations, underlying XP phenotype, in Pakistani population. © 2018 Japanese Teratology Society.

Mutation Analysis of Consanguineous Moroccan Patients with Parkinson’s Disease Combining Microarray and Gene Panel

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Ahmed Bouhouche

2017-10-01

Full Text Available During the last two decades, 15 different genes have been reported to be responsible for the monogenic form of Parkinson’s disease (PD, representing a worldwide frequency of 5–10%. Among them, 10 genes have been associated with autosomal recessive PD, with PRKN and PINK1 being the most frequent. In a cohort of 145 unrelated Moroccan PD patients enrolled since 2013, 19 patients were born from a consanguineous marriage, of which 15 were isolated cases and 4 familial. One patient was homozygous for the common LRRK2 G2019S mutation and the 18 others who did not carry this mutation were screened for exon rearrangements in the PRKN gene using Affymetrix Cytoscan HD microarray. Two patients were determined homozygous for PRKN exon-deletions, while another patient presented with compound heterozygous inheritance (3/18, 17%. Two other patients showed a region of homozygosity covering the 1p36.12 locus and were sequenced for the candidate PINK1 gene, which revealed two homozygous point mutations: the known Q456X mutation in exon 7 and a novel L539F variation in exon 8. The 13 remaining patients were subjected to next-generation sequencing (NGS that targeted a panel of 22 PD-causing genes and overlapping phenotypes. NGS data showed that two unrelated consanguineous patients with juvenile-onset PD (12 and 13 years carried the same homozygous stop mutation W258X in the ATP13A2 gene, possibly resulting from a founder effect; and one patient with late onset (76 years carried a novel heterozygous frameshift mutation in SYNJ1. Clinical analysis showed that patients with the ATP13A2 mutation developed juvenile-onset PD with a severe phenotype, whereas patients having either PRKN or PINK1 mutations displayed early-onset PD with a relatively mild phenotype. By identifying pathogenic mutations in 45% (8/18 of our consanguineous Moroccan PD series, we demonstrate that the combination of chromosomal microarray analysis and NGS is a powerful approach to

New MCM8 mutation associated with premature ovarian insufficiency and chromosomal instability in a highly consanguineous Tunisian family.

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Bouali, Nouha; Francou, Bruno; Bouligand, Jérôme; Imanci, Dilek; Dimassi, Sarra; Tosca, Lucie; Zaouali, Monia; Mougou, Soumaya; Young, Jacques; Saad, Ali; Guiochon-Mantel, Anne

2017-10-01

To identify the gene(s) involved in the etiology of premature ovarian insufficiency in a highly consanguineous Tunisian family. Genetic analysis of a large consanguineous family with several affected siblings. University hospital-based cytogenetics and molecular genetics laboratories. A highly consanguineous Tunisian family with several affected siblings born to healthy second-degree cousins. None. Targeted exome sequencing was performed by next-generation sequencing for affected family members. Mutations were validated by Sanger sequencing. Functional experiments were performed to explore the deleterious effects of the identified mutation. DNA damage was induced by increasing mitomycin C (MMC) concentrations on cultured peripheral lymphocytes. Analysis of the next-generation sequencing data revealed a new homozygous missense mutation in the minichromosome maintenance 8 gene (MCM8).This homozygous mutation (c. 482A>C; p.His161Pro) was predicted to be deleterious and segregated with the disease in the family. MCM8 participates in homologous recombination during meiosis and DNA double-stranded break repair by dimerizing with MCM9. Mcm8 knock out results in an early block in follicle development and small gonads. Given this, we tested the chromosomal breakage repair capacity of homozygous and heterozygous MCM8 p.His161Pro mutation on cultured peripheral lymphocytes exposed to increasing MMC concentrations. We found that chromosomal breakage after MMC exposure was significantly higher in cells from homozygously affected individuals than in those from a healthy control. Our findings provide additional support to the view that MCM8 mutations are involved in the primary ovarian insufficiency phenotype. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

The Oenothera plastome mutator: effect of UV irradiation and nitroso-methyl urea on mutation frequencies

International Nuclear Information System (INIS)

Sears, B.B.; Sokalski, M.B.

1991-01-01

Oenothera plants homozygous for a recessive plastome mutator allele (pm) showed spontaneous mutation frequencies for plastome genes that are 200-fold higher than spontaneous levels. Mutations occurred at high frequencies in plants grown in the field, in a glasshouse, or as leaf tip cultures under fluorescent light, indicating that the plastome mutator activity is UV-independent. However, the chlorotic sectors became visible at an earlier stage of development when seedlings were irradiated, compared to seedlings that were not exposed to UV. These results imply that the rate of sorting-out was increased by the irradiation treatment, possibly due to a decrease in the effective number of multiplication-competent plastids, or a reduction in the extent of cytoplasmic mixing. Nitroso-methyl urea treatment of seeds had a dramatic effect on mutation frequency in both wild-type and plastome mutator samples. When the background mutation rates were low, the combination of the plastome mutator nucleus and the chemical mutagenesis treatment resulted in a synergistic effect, suggesting that the plastome mutator may involve a cpDNA repair pathway. (author)

To pace or not to pace: a pilot study of four- and five-gaited Icelandic horses homozygous for the DMRT3 'Gait Keeper' mutation.

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Jäderkvist Fegraeus, K; Hirschberg, I; Árnason, T; Andersson, L; Velie, B D; Andersson, L S; Lindgren, G

2017-12-01

The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tölt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutant (AA) Icelandic horses are reported to pace. The aim of the study was to genetically compare four- and five-gaited (i.e. horses with and without the ability to pace) AA Icelandic horses by performing a genome-wide association (GWA) analysis. All horses (n = 55) were genotyped on the 670K Axiom Equine Genotyping Array, and a GWA analysis was performed using the genabel package in r. No SNP demonstrated genome-wide significance, implying that the ability to pace goes beyond the presence of a single gene variant. Despite its limitations, the current study provides additional information regarding the genetic complexity of pacing ability in horses. However, to fully understand the genetic differences between four- and five-gaited AA horses, additional studies with larger sample materials and consistent phenotyping are needed. © 2017 Stichting International Foundation for Animal Genetics.

Fanconi anemia founder mutation in Macedonian patients.

Science.gov (United States)

Madjunkova, Svetlana; Kocheva, Svetlana A; Plaseska-Karanfilska, Dijana

2014-01-01

Fanconi anemia (FA) is a rare autosomal recessive disorder clinically characterized by developmental abnormalities, progressive bone marrow failure (BMF) and profound cancer predisposition. Approximately 65% of all affected individuals have mutation in the FANCA (Fanconi anemia complementation group A) gene. The mutation spectrum of the FANCA gene is highly heterogeneous. FA-A is usually associated with private FANCA mutations in individual families. We describe 3 unrelated patients with FA with a similar clinical presentation: BMF, renal anomalies and café-au-lait pigmentation without major skeletal abnormality. The molecular analysis of the FANCA gene using the FA MLPA kit P031-A2/P032 FANCA, showed homozygous deletion of exon 3 in all 3 patients. Molecular analysis of the flanking regions of exon 3 precisely defined unique deletion of 2,040 bp and duplication of C (1788_3828dupC). These are the first 3 patients homozygous for deletion of FANCA exon 3 described to date. Although not related, the patients originated from the same Gypsy-like ethnic population. We conclude that c.190-256_283 + 1680del2040 dupC mutation in the FANCA gene is a founder mutation in Macedonian FA patients of Gypsy-like ethnic origin. Our finding has very strong implications for these patients in formulating diagnostic and carrier-screening strategy for BMF and FA and to enable comprehensive genetic counseling. © 2013 S. Karger AG, Basel.

Homozygous familial hypercholesterolaemia

DEFF Research Database (Denmark)

Cuchel, Marina; Bruckert, Eric; Ginsberg, Henry N

2014-01-01

AIMS: Homozygous familial hypercholesterolaemia (HoFH) is a rare life-threatening condition characterized by markedly elevated circulating levels of low-density lipoprotein cholesterol (LDL-C) and accelerated, premature atherosclerotic cardiovascular disease (ACVD). Given recent insights into the......AIMS: Homozygous familial hypercholesterolaemia (HoFH) is a rare life-threatening condition characterized by markedly elevated circulating levels of low-density lipoprotein cholesterol (LDL-C) and accelerated, premature atherosclerotic cardiovascular disease (ACVD). Given recent insights...... into the heterogeneity of genetic defects and clinical phenotype of HoFH, and the availability of new therapeutic options, this Consensus Panel on Familial Hypercholesterolaemia of the European Atherosclerosis Society (EAS) critically reviewed available data with the aim of providing clinical guidance...... 5 and no later than 8 years. The number of therapeutic approaches has increased following approval of lomitapide and mipomersen for HoFH. Given the severity of ACVD, we recommend regular follow-up, including Doppler echocardiographic evaluation of the heart and aorta annually, stress testing and...

Prenatal diagnosis of homozygous familial hypercholesterolaemia

International Nuclear Information System (INIS)

Brown, M.S.; Kovanen, P.T.; Goldstein, J.L.; Eeckels, R.; Vandenberghe, K.; Van Den Berghe, H.; Fryns, J.P.; Cassiman, J.J.

1978-01-01

Cultured amniotic-fluid cells from a fetus at risk for homozygous familial hypercholesterolaemia (F.H.) almost completely lacked cell-surface receptors for plasma low-density lipoprotein (L.D.L.), as evidenced by direct measurement of binding, uptake, and degradation of 125 I-L.D.L. Functional consequences of L.D.L. binding to the receptor - i.e., suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase and stimulation of cholesterol esterification - were proportionately reduced when compared with results in cultured amniotic cells from two control fetuses. On the basis of these findings, homozygous F.H. was diagnosed and the pregnancy was terminated at the 20th week. The diagnosis of homozygous F.H. was confirmed by a serum-cholesterol of the aborted fetus of 279 mg/dl, a value 9 times the mean of four control fetuses of similar gestational age. More than 80% of the serum-cholesterol of the affected fetus was contained within L.D.L. Prenatal diagnosis of homozygous F.H. now seems practical; moreover, the finding of a raised serum-L.D.L. in the affected fetus indicates that the L.D.L. receptor is normally functional as early as the 20th week of fetal life. (author)

Inactivation of Stac3 causes skeletal muscle defects and perinatal death in mice

OpenAIRE

Reinholt, Brad Michael

2012-01-01

The Src homology 3 domain (SH3) and cysteine rich domain (C1) 3 (Stac3) gene is a novel gene copiously expressed in skeletal muscle. The objective of this research was to determine the role of Stac3 in development, specifically in skeletal muscle. We achieved this objective by evaluating the phenotypic effects of Stac3 gene inactivation on development in mice. At birth homozygous Stac3 null (Stac3-/-) mice died perinatally and remained in fetal position with limp limbs, but possessed otherwis...

Four Novel p.N385K, p.V36A, c.1033–1034insT and c.1417–1418delCT Mutations in the Sphingomyelin Phosphodiesterase 1 (SMPD1 Gene in Patients with Types A and B Niemann-Pick Disease (NPD

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Masoumeh Dehghan Manshadi

2015-03-01

Full Text Available Background: Types A and B Niemann-Pick disease (NPD are autosomal-recessive lysosomal storage disorders caused by the deficient activity of acid sphingomyelinase due to mutations in the sphingomyelin phosphodiesterase 1 (SMPD1 gene. Methods: In order to determine the prevalence and distribution of SMPD1 gene mutations, the genomic DNA of 15 unrelated Iranian patients with types A and B NPD was examined using PCR, DNA sequencing and bioinformatics analysis. Results: Of 8 patients with the p.G508R mutation, 5 patients were homozygous, while the other 3 were heterozygous. One patient was heterozygous for both the p.N385K and p.G508R mutations. Another patient was heterozygous for both the p.A487V and p.G508R mutations. Two patients (one homozygous and one heterozygous showed the p.V36A mutation. One patient was homozygous for the c.1033–1034insT mutation. One patient was homozygous for the c.573delT mutation, and 1 patient was homozygous for the c.1417–1418delCT mutation. Additionally, bioinformatics analysis indicated that two new p.V36A and p.N385K mutations decreased the acid sphingomyelinase (ASM protein stability, which might be evidence to suggest the pathogenicity of these mutations. Conclusion: with detection of these new mutations, the genotypic spectrum of types A and B NPD is extended, facilitating the definition of disease-related mutations. However, more research is essential to confirm the pathogenic effect of these mutations.

Growth hormone receptor gene mutations in two Italian patients with Laron Syndrome.

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Fassone, L; Corneli, G; Bellone, S; Camacho-Hübner, C; Aimaretti, G; Cappa, M; Ubertini, G; Bona, G

2007-05-01

Laron Syndrome (LS) represents a condition characterized by GH insensitivity caused by molecular defects in the GH receptor (GHR) gene or in the post-receptor signalling pathway. We report the molecular characterization of two unrelated Italian girls from Sicily diagnosed with LS. The DNA sequencing of the GHR gene revealed the presence of different nonsense mutations, occurring in the same background haplotype. The molecular defects occurred in the extracellular domain of the GHR leading to a premature termination signal and to a truncated non-functional receptor. In one patient, a homozygous G to T transversion, in exon 6, led to the mutation GAA to TAA at codon 180 (E180X), while in the second patient a homozygous C to T transition in exon 7 was detected, causing the CGA to TAA substitution at codon 217 (R217X). Both probands presented the polymorphisms Gly168Gly and Ile544Leu in a homozygous state in exons 6 and 10, respectively. The E180X represents a novel defect of the GHR gene, while the R217X mutation has been previously reported in several patients from different ethnic backgrounds but all from countries located in the Mediterranean and Middle Eastern region.

Complicated biallelic inactivation of Pten in radiation-induced mouse thymic lymphomas

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Yu [Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522 (Japan); Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Takabatake, Takashi; Kakinuma, Shizuko; Amasaki, Yoshiko; Nishimura, Mayumi; Imaoka, Tatsuhiko; Yamauchi, Kazumi; Shang, Yi [Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Miyoshi-Imamura, Tomoko [Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Genetic Counseling Program, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyou-ku, Tokyo 112-8610 (Japan); Nogawa, Hiroyuki [Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522 (Japan); Kobayashi, Yoshiro [Department of Biomolecular Science, Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510 (Japan); Shimada, Yoshiya, E-mail: y_shimad@nirsgo.jp [Experimental Radiobiology for Children' s Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2010-04-01

Inactivation of the phosphatase and tensin homolog gene (Pten) occurs via multiple tissue-dependent mechanisms including epigenetic silencing, point mutations, insertions, and deletions. Although frequent loss of heterozygosity around the Pten locus and plausible involvement of epigenetic silencing have been reported in radiation-induced thymic lymphomas, the proportion of lymphomas with inactivated Pten and the spectrum of causal aberrations have not been extensively characterized. Here, we assessed the mode of Pten inactivation by comprehensive analysis of the expression and alteration of Pten in 23 radiation-induced thymic lymphomas developed in B6C3F1 mice. We found no evidence for methylation-associated silencing of Pten; rather, complex structural abnormalities comprised of missense and nonsense mutations, 1- and 3-bp insertions, and focal deletions were identified in 8 of 23 lymphomas (35%). Sequencing of deletion breakpoints suggested that aberrant V(D)J recombination and microhomology-mediated rearrangement were responsible for the focal deletions. Seven of the 8 lymphomas had biallelic alterations, and 4 of them did not express Pten protein. These Pten aberrations coincided with downstream Akt phosphorylation. In conclusion, we demonstrate that Pten inactivation is frequently biallelic and is caused by a variety of structural abnormalities (rather than by epigenetic silencing) and is involved in radiation-induced lymphomagenesis.

The relationship between thrombophilic mutations and preeclampsia: a prospective case-control study

International Nuclear Information System (INIS)

Yalinkaya, A.; Erdemoglu, M.; Akdeniz, N.; Kale, A.; Kale, E.

2006-01-01

Preeclampsia and its association with thrombophillia remain controversial, due to inconsistent results in different studies, which different ethnic groups, selection criteria, and patient numbers. The aim of this study was to determine the relationship between thrombophillia and preeclamptic patients in our region. In a prospective case-control study, we compared 100 consecutive women with preeclampsia and eclampsia (group 1) with 100 normal pregnant women (group 2). All women were tested two months after delivery for mutations of factor V Leiden, methylenetetrahydrofolate reductase (MTHFR), and prothrombin gene mutation mutataion as well as for deficiencies of protein C, protein S, and antithrmbin III. A thrombophilic mutation was found in 42 (42%) and 28(28%) women in group I and group II, respectively (P+0.27, OR 1.5, 95% CI 1.0-2.2). The incidence of Factor V Leiden mutation (heterozygous), prothrombin mutation (heterozygous), prothrombin mutation (homozygous), MTHFR mutation (homozygous) was not statistically significant in group 1 compared with group 2 (P>0.05). Also, deficiencies of protein S, protein c and antithrombin III were not statistically significant in group I com pared with group II (P>0.05). There was no difference in thrombophilic mutations between preeclamptic patients and normal pregnant women in our region. Therefore, we suggest that preeclamptic patients should not be tested for thrombophilia. (author)

HPV-16 L1 genes with inactivated negative RNA elements induce potent immune responses

International Nuclear Information System (INIS)

Rollman, Erik; Arnheim, Lisen; Collier, Brian; Oeberg, Daniel; Hall, Haakan; Klingstroem, Jonas; Dillner, Joakim; Pastrana, Diana V.; Buck, Chris B.; Hinkula, Jorma; Wahren, Britta; Schwartz, Stefan

2004-01-01

Introduction of point mutations in the 5' end of the human papillomavirus type 16 (HPV-16) L1 gene specifically inactivates negative regulatory RNA processing elements. DNA vaccination of C57Bl/6 mice with the mutated L1 gene resulted in improved immunogenicity for both neutralizing antibodies as well as for broad cellular immune responses. Previous reports on the activation of L1 by codon optimization may be explained by inactivation of the regulatory RNA elements. The modified HPV-16 L1 DNA that induced anti-HPV-16 immunity may be seen as a complementary approach to protein subunit immunization against papillomavirus

Enhanced vulnerability of human proteins towards disease-associated inactivation through divergent evolution.

Science.gov (United States)

Medina-Carmona, Encarnación; Fuchs, Julian E; Gavira, Jose A; Mesa-Torres, Noel; Neira, Jose L; Salido, Eduardo; Palomino-Morales, Rogelio; Burgos, Miguel; Timson, David J; Pey, Angel L

2017-09-15

Human proteins are vulnerable towards disease-associated single amino acid replacements affecting protein stability and function. Interestingly, a few studies have shown that consensus amino acids from mammals or vertebrates can enhance protein stability when incorporated into human proteins. Here, we investigate yet unexplored relationships between the high vulnerability of human proteins towards disease-associated inactivation and recent evolutionary site-specific divergence of stabilizing amino acids. Using phylogenetic, structural and experimental analyses, we show that divergence from the consensus amino acids at several sites during mammalian evolution has caused local protein destabilization in two human proteins linked to disease: cancer-associated NQO1 and alanine:glyoxylate aminotransferase, mutated in primary hyperoxaluria type I. We demonstrate that a single consensus mutation (H80R) acts as a disease suppressor on the most common cancer-associated polymorphism in NQO1 (P187S). The H80R mutation reactivates P187S by enhancing FAD binding affinity through local and dynamic stabilization of its binding site. Furthermore, we show how a second suppressor mutation (E247Q) cooperates with H80R in protecting the P187S polymorphism towards inactivation through long-range allosteric communication within the structural ensemble of the protein. Our results support that recent divergence of consensus amino acids may have occurred with neutral effects on many functional and regulatory traits of wild-type human proteins. However, divergence at certain sites may have increased the propensity of some human proteins towards inactivation due to disease-associated mutations and polymorphisms. Consensus mutations also emerge as a potential strategy to identify structural hot-spots in proteins as targets for pharmacological rescue in loss-of-function genetic diseases. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please

Homozygous PARK7 Mutation in Parkinson’s Disease: Case Report of Two Brothers

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Hülya Apaydın

2008-06-01

Full Text Available OBJECTIVE: Genetic studies for Parkinson’s disease (PD which have been increased during last few years have shown that parkin (PARK2, DJ-1 (PARK7 and PINK-1 (PARK6 mutations can cause autosomal recessive early-onset parkinsonism. OBJECTIVE: The aim of this study was to investigate by genetic screening methods, the presence of possible genetic mutations in two siblings who have developed PD. METHODS: In these two brothers, PD started at the age of 48 with cervical dystonia and bradykinesia on the left arm, and 56 with tremor on the right hand, respectively. Although they had a favorable response to levodopa, they developed wearing-off phenomenon without dyskinesia on the 4th year. Besides dystonia, the younger brother experienced psychosis and impulse control disorder, as well. Family history revealed first degree consanguinity and the father had also a diagnosis of PD. PD progressed rather slowly in both, but unfortunately the older brother died due to lung cancer 10 years after the initial diagnosis of PD, while he was on the stage 2 of Hoehn-Yahr scale. The younger brother is still on our follow-up at the 7th year of his PD. Informed consent was obtained and blood samples were sent to the genetic department of Juntendo University in Japan for genetic analysis. Parkin gene mutation and DJ-1 gene mutation were analyzed on the PARK7 locus, by automated direct nucleotide sequencing and performed gene dosage assay using TaqMan real-time quantitive PCR. RESULTS: After excluding the parkin mutation the presence of PARK7 was detected in both siblings with haplotype analysis. DJ-1 gene mutation analysis responsible for PARK7, revealed a deletion on intron 1. CONCLUSION: A rarely encountered PARK7 mutation was identified in two brothers having slowly progressive PD and a favorable response to levodopa, one of whom also had psychotic symptoms. As in the presented cases, the genetic studies performed on early-onset PD patients with positive family

Novel SCARB2 mutation in action myoclonus-renal failure syndrome and evaluation of SCARB2 mutations in isolated AMRF features

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Hopfner Franziska

2011-10-01

Full Text Available Abstract Background Action myoclonus-renal failure syndrome is a hereditary form of progressive myoclonus epilepsy associated with renal failure. It is considered to be an autosomal-recessive disease related to loss-of-function mutations in SCARB2. We studied a German AMRF family, additionally showing signs of demyelinating polyneuropathy and dilated cardiomyopathy. To test the hypothesis whether isolated appearance of individual AMRF syndrome features could be related to heterozygote SCARB2 mutations, we screened for SCARB2 mutations in unrelated patients showing isolated AMRF features. Methods In the AMRF family all exons of SCARB2 were analyzed by Sanger sequencing. The mutation screening of unrelated patients with isolated AMRF features affected by either epilepsy (n = 103, progressive myoclonus epilepsy or generalized epilepsy, demyelinating polyneuropathy (n = 103, renal failure (n = 192 or dilated cardiomyopathy (n = 85 was performed as high resolution melting curve analysis of the SCARB2 exons. Results A novel homozygous 1 bp deletion (c.111delC in SCARB2 was found by sequencing three affected homozygous siblings of the affected family. A heterozygous sister showed generalized seizures and reduction of nerve conduction velocity in her legs. No mutations were found in the epilepsy, renal failure or dilated cardiomyopathy samples. In the polyneuropathy sample two individuals with demyelinating disease were found to be carriers of a SCARB2 frameshift mutation (c.666delCCTTA. Conclusions Our findings indicate that demyelinating polyneuropathy and dilated cardiomyopathy are part of the action myoclonus-renal failure syndrome. Moreover, they raise the possibility that in rare cases heterozygous SCARB2 mutations may be associated with PNP features.

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.

A homozygous missense variant in VWA2, encoding an interactor of the Fraser-complex, in a patient with vesicoureteral reflux.

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Amelie T van der Ven

Full Text Available Congenital anomalies of the kidney and urinary tract (CAKUT are the most common cause (40-50% of chronic kidney disease (CKD in children. About 40 monogenic causes of CAKUT have so far been discovered. To date less than 20% of CAKUT cases can be explained by mutations in these 40 genes. To identify additional monogenic causes of CAKUT, we performed whole exome sequencing (WES and homozygosity mapping (HM in a patient with CAKUT from Indian origin and consanguineous descent. We identified a homozygous missense mutation (c.1336C>T, p.Arg446Cys in the gene Von Willebrand factor A domain containing 2 (VWA2. With immunohistochemistry studies on kidneys of newborn (P1 mice, we show that Vwa2 and Fraser extracellular matrix complex subunit 1 (Fras1 co-localize in the nephrogenic zone of the renal cortex. We identified a pronounced expression of Vwa2 in the basement membrane of the ureteric bud (UB and derivatives of the metanephric mesenchyme (MM. By applying in vitro assays, we demonstrate that the Arg446Cys mutation decreases translocation of monomeric VWA2 protein and increases translocation of aggregated VWA2 protein into the extracellular space. This is potentially due to the additional, unpaired cysteine residue in the mutated protein that is used for intermolecular disulfide bond formation. VWA2 is a known, direct interactor of FRAS1 of the Fraser-Complex (FC. FC-encoding genes and interacting proteins have previously been implicated in the pathogenesis of syndromic and/or isolated CAKUT phenotypes in humans. VWA2 therefore constitutes a very strong candidate in the search for novel CAKUT-causing genes. Our results from in vitro experiments indicate a dose-dependent neomorphic effect of the Arg446Cys homozygous mutation in VWA2.

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

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Podhajska, Agata; Musso, Alessandra; Trancikova, Alzbeta; Stafa, Klodjan; Moser, Roger; Sonnay, Sarah; Glauser, Liliane; Moore, Darren J

2012-01-01

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

Craniofacial abnormalities in homozygous Small eye (Sey/Sey) embryos and newborn mice.

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Kaufman, M H; Chang, H H; Shaw, J P

1995-06-01

The Small eye (Sey) gene in the mouse is lethal in the homozygous state. It is located on chromosome 2, is a mutation in the Pax-6 gene, and is genetically homologous with the human aniridia 2 (AN2) gene mutation. Numerous studies over the last few years, using genetic and molecular biological approaches, have investigated both the location of the gene as well as its possible mode of action. In the homozygous state, the primary defect appears to be limited to the failure of differentiation of the presumptive lens and nasal placodes. Such mice therefore display a characteristic phenotype; they possess neither eyes nor any nasal derivatives. Their heterozygous (Sey/+) and normal (+/+) littermates may be distinguished before birth only by a detailed examination of their eyes. Few detailed morphological/histological studies have been undertaken to date in the Sey/Sey embryos and newborn, and in the present study we describe a variety of craniofacial abnormalities that have not previously been reported. We observed, with one exception, delayed closure of the palate, and the presence in 80% of mice of an abnormal complement of upper incisor teeth, so that 35% possessed 1 supernumerary tooth while 45% possessed 2 supernumerary teeth. In these mice, a total of either 3 or 4, rather than the normal complement of 2, upper incisor teeth were present. Possibly the most unexpected finding, however, was the presence of a median cartilaginous rod-like structure which protruded between the 2 maxillae to give the Alizarin red S and Alcian blue-stained 'cleared' skulls of the newborn mice a characteristic 'unicorn-like' appearance. While this structure appeared to be a rostral extension of the chondrocranium, its exact derivation is unclear.

DNA replication error-induced extinction of diploid yeast.

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Herr, Alan J; Kennedy, Scott R; Knowels, Gary M; Schultz, Eric M; Preston, Bradley D

2014-03-01

Genetic defects in DNA polymerase accuracy, proofreading, or mismatch repair (MMR) induce mutator phenotypes that accelerate adaptation of microbes and tumor cells. Certain combinations of mutator alleles synergistically increase mutation rates to levels that drive extinction of haploid cells. The maximum tolerated mutation rate of diploid cells is unknown. Here, we define the threshold for replication error-induced extinction (EEX) of diploid Saccharomyces cerevisiae. Double-mutant pol3 alleles that carry mutations for defective DNA polymerase-δ proofreading (pol3-01) and accuracy (pol3-L612M or pol3-L612G) induce strong mutator phenotypes in heterozygous diploids (POL3/pol3-01,L612M or POL3/pol3-01,L612G). Both pol3-01,L612M and pol3-01,L612G alleles are lethal in the homozygous state; cells with pol3-01,L612M divide up to 10 times before arresting at random stages in the cell cycle. Antimutator eex mutations in the pol3 alleles suppress this lethality (pol3-01,L612M,eex or pol3-01,L612G,eex). MMR defects synergize with pol3-01,L612M,eex and pol3-01,L612G,eex alleles, increasing mutation rates and impairing growth. Conversely, inactivation of the Dun1 S-phase checkpoint kinase suppresses strong pol3-01,L612M,eex and pol3-01,L612G,eex mutator phenotypes as well as the lethal pol3-01,L612M phenotype. Our results reveal that the lethal error threshold in diploids is 10 times higher than in haploids and likely determined by homozygous inactivation of essential genes. Pronounced loss of fitness occurs at mutation rates well below the lethal threshold, suggesting that mutator-driven cancers may be susceptible to drugs that exacerbate replication errors.

SMARCA4 inactivating mutations cause concomitant Coffin-Siris syndrome, microphthalmia and small-cell carcinoma of the ovary hypercalcaemic type.

Science.gov (United States)

Errichiello, Edoardo; Mustafa, Noor; Vetro, Annalisa; Notarangelo, Lucia Dora; de Jonge, Hugo; Rinaldi, Berardo; Vergani, Debora; Giglio, Sabrina Rita; Morbini, Patrizia; Zuffardi, Orsetta

2017-09-01

SMARCA4 chromatin remodelling factor is mutated in 11% of Coffin-Siris syndrome (CSS) patients and in almost all small-cell carcinoma of the ovary hypercalcaemic type (SCCOHT) tumours. Missense mutations with gain-of-function or dominant-negative effects are associated with CSS, whereas inactivating mutations, leading to loss of SMARCA4 expression, have been exclusively found in SCCOHT. We applied whole-exome sequencing to study a 15-year-old patient with mild CSS who concomitantly developed SCCOHT at age 13 years. Interestingly, our patient also showed congenital microphthalmia, which has never previously been reported in CSS patients. We detected a de novo germline heterozygous nonsense mutation in exon 19 of SMARCA4 (c.2935C > T;p.Arg979*), and a somatic frameshift mutation in exon 6 (c.1236_1236delC;p.Gln413Argfs*88), causing complete loss of SMARCA4 immunostaining in the tumour. The immunohistochemical findings are supported by the observation that the c.2935C > T mutant transcript was detected by reverse transcription polymerase chain reaction at a much lower level than the wild-type allele in whole blood and the lymphoblastoid cell line of the proband, confirming nonsense-mediated mRNA decay. Accordingly, immunoblotting demonstrated that there was approximately half the amount of SMARCA4 protein in the proband's cells as in controls. This study suggests that SMARCA4 constitutional mutations associated with CSS are not necessarily non-truncating, and that haploinsufficiency may explain milder CSS phenotypes, as previously reported for haploinsufficient ARID1B. In addition, our case supports the dual role of chromatin remodellers in developmental disorders and cancer, as well as the involvement of SMARCA4 in microphthalmia, confirming previous findings in mouse models and the DECIPHER database. Finally, we speculate that mild CSS might be under-recognized in a proportion of SCCOHT patients harbouring SMARCA4 mutations. © 2017 The Authors. The

Characteristic brain MRI findings in ataxia-neuropathy spectrum related to POLG mutation.

Science.gov (United States)

Henao, Adriana I; Pira, Sonia; Herrera, Diego A; Vargas, Sergio A; Montoya, Jorge; Castillo, Mauricio

2016-02-01

Patients with mutations in the polymerase gamma gene (POLG) may present with progressive ataxia and in such situations neuroimaging findings may suggest the diagnosis. Herein we report a patient with a POLG gene W748S homozygous mutation and characteristic lesions in the thalamus, cerebellum and inferior olivary nucleus seen on magnetic resonance imaging. © The Author(s) 2016.

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

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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.

Mutation of Haemophilus influenzae transforming DNA in vitro with near-ultraviolet radiation: action spectrum

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Cabrera-Juarez, E; Setlow, J K [Escuela Nacional de Ciencias Biologicas, Mexico City. Dept. de Bioquimica; Oak Ridge National Lab., Tenn. (USA). Biology Div.)

1976-05-01

Mutations were produced in purified transforming DNA from Haemophilus influenzae by near UV radiation and were assayed as mutants among cells transformed with irradiated DNA. The maximum efficiency of mutation induction was at around 334 nm, and the efficiency dropped off steeply at lower and higher wavelengths. The difference between the action spectrum for mutation and that for the oxygen-independent inactivation of transforming DNA, which had a shoulder at 365 nm, indicates that there are different lesions involved in the inactivating and mutagenic effects of near-UV. The presence of histidine during irradiation enhanced the mutagenic effect at 334 and 365 nm, although it protected against inactivation at 365 nm. The effective near-UV wavelengths for in vitro mutation are to some extent the same as the effective wavelengths for mutation in vivo reported previously. These findings indicate that mutations are produced in vivo by near-UV with DNA as the primary target molecule rather than by a secondary non-photochemical reaction between DNA and some other cell component.

Identification of a breast cancer family double heterozygote for RAD51C and BRCA2 gene mutations

DEFF Research Database (Denmark)

Ahlborn, Lise B; Steffensen, Ane Y; Jønson, Lars

2015-01-01

for mutations in the RAD51C and BRCA2 genes. The RAD51C missense mutation p.Arg258His has previously been identified in a homozygous state in a patient with Fanconi anemia. This mutation is known to affect the DNA repair function of the RAD51C protein. The BRCA2 p.Leu3216Leu synonymous mutation has not been...

A Founder Mutation in MYO7A Underlies a Significant Proportion of Usher Syndrome in Indigenous South Africans: Implications for the African Diaspora.

Science.gov (United States)

Roberts, Lisa; George, Siddiqah; Greenberg, Jacquie; Ramesar, Raj S

2015-10-01

Research over the past 25 years at the University of Cape Town has led to the identification of causative mutations in 17% of the 1416 families in the Retinal Degenerative Diseases (RDD) biorepository in South Africa. A low rate of mutation detection has been observed in patients of indigenous African origin, hinting at novel genes and mutations in this population. Recently, however, data from our translational research program showed two unrelated indigenous African families with Usher syndrome (USH), with the same homozygous MYO7A mutation. Therefore, the extent to which this mutation contributes toward the disease burden in South Africa was investigated. Cohorts of unrelated indigenous South African probands with different RDD diagnoses were tested for the MYO7A c.6377delC mutation. Familial cosegregation analysis was performed for homozygous probands, clinical data were evaluated, and SNP haplotypes were analyzed. This homozygous MYO7A mutation underlies a remarkable 43% of indigenous African USH cases investigated in this study, the majority of which (60%) were diagnosed clinically with Type 2 USH. All homozygotes shared a common haplotype. This mutation does not appear to cause nonsyndromic vision loss. Of interest is the origin of this common mutation relevant to the Bantu population migration into southern Africa. Further investigation of the phenotype may elucidate the disease biology, and perhaps reveal a larger cohort with the same mutation, with which to assess the impact of environmental and genetic modifiers and evaluate therapeutic trials.

Ploidy and liquid-holding recovery of yeasts sensitive to radiation and nitrous acid

International Nuclear Information System (INIS)

Arman, I.P.; Dutova, T.A.

1975-01-01

NA-Inactivation of isogeneic yeasts Sacch. cerevisiae from the collection of LIYaF, normal and sensitive to radiation and Na (xrs1-5 mutation), was studied as a function of the ploidy of the genome and the conditions of incubation after the influence of the mutagen. Normal cells of highly homozygous PG strains exhibit a protective effect of ploidy: the haploid is the most sensitive to the inactivating action of NA, and with increasing number of chromosome sets the resistance increases substantially. With a different polyploid series of yeasts of the same origin, where di-, tri-, and tetraploids are homozygous for the mutation xrs1-5, this effect is absent. Moreover, the doubling of the genome leads to a sharp increase in the sensitivity of the cells to NA, while the shape of the dose-versus-effect curves becomes exponential, in contrast to sigmoid for the initial control strains. This fact of the ''reverse effect of ploidy'' is evidence of an impairment of the reapir of dominant lethals - the basic cause of death of diploid and polyploid cells - in the xrs1-5 strains. Exposure of yeasts in buffer for 24 h (LHR conditions) after the influence of NA modifies the level of inactivation, depending on the genotype and ploidy of the cells. In yeast strains of a different origin (from Berkeley, United States) with a normal sensitivity to NA (n, 2n, 3n), the survival under LHR conditions is practically unchanged for 24 h. The haploids of highly homozygous strains (LIYaF) - normal and xrs1-5 mutant - also do not recover. However, diploidizationand a further increase in the number of genomes leads to the fact that the death under LH conditions increases sharply in normal highly homozygous yeasts (PG) - by at least an order of magnitude in 24 h of incubation in buffer; in this case the titer of the cells remains constant, while the loss of viability is proportional to the time. A significant effect of recovery is detected in homozygotes for the xrs1 mutation (2n, 3n, 4n). It

HSJ1-related hereditary neuropathies: novel mutations and extended clinical spectrum.

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Gess, Burkhard; Auer-Grumbach, Michaela; Schirmacher, Anja; Strom, Tim; Zitzelsberger, Manuela; Rudnik-Schöneborn, Sabine; Röhr, Dominik; Halfter, Hartmut; Young, Peter; Senderek, Jan

2014-11-04

To determine the nature and frequency of HSJ1 mutations in patients with hereditary motor and hereditary motor and sensory neuropathies. Patients were screened for mutations by genome-wide or targeted linkage and homozygosity studies, whole-exome sequencing, and Sanger sequencing. RNA and protein studies of skin fibroblasts were used for functional characterization. We describe 2 additional mutations in the HSJ1 gene in a cohort of 90 patients with autosomal recessive distal hereditary motor neuropathy (dHMN) and Charcot-Marie-Tooth disease type 2 (CMT2). One family with a dHMN phenotype showed the homozygous splice-site mutation c.229+1G>A, which leads to retention of intron 4 in the HSJ1 messenger RNA with a premature stop codon and loss of protein expression. Another family, presenting with a CMT2 phenotype, carried the homozygous missense mutation c.14A>G (p.Tyr5Cys). This mutation was classified as likely disease-related by several automatic algorithms for prediction of possible impact of an amino acid substitution on the structure and function of proteins. Both mutations cosegregated with autosomal recessive inheritance of the disease and were absent from the general population. Taken together, in our cohort of 90 probands, we confirm that HSJ1 mutations are a rare but detectable cause of autosomal recessive dHMN and CMT2. We provide clinical and functional information on an HSJ1 splice-site mutation and report the detailed phenotype of 2 patients with CMT2, broadening the phenotypic spectrum of HSJ1-related neuropathies. © 2014 American Academy of Neurology.

BAG3 Directly Interacts with Mutated alphaB-Crystallin to Suppress Its Aggregation and Toxicity

NARCIS (Netherlands)

Hishiya, Akinori; Salman, Mortada Najem; Carra, Serena; Kampinga, Harm H.; Takayama, Shinichi

2011-01-01

A homozygous disruption or genetic mutation of the bag3 gene causes progressive myofibrillar myopathy in mouse and human skeletal and cardiac muscle disorder while mutations in the small heat shock protein aB-crystallin gene ( CRYAB) are reported to be responsible for myofibrillar myopathy. Here, we

Inactivation of IL11 signaling causes craniosynostosis, delayed tooth eruption, and supernumerary teeth

DEFF Research Database (Denmark)

Nieminen, Pekka; Morgan, Neil V; Fenwick, Aimée L

2011-01-01

Craniosynostosis and supernumerary teeth most often occur as isolated developmental anomalies, but they are also separately manifested in several malformation syndromes. Here, we describe a human syndrome featuring craniosynostosis, maxillary hypoplasia, delayed tooth eruption, and supernumerary...... teeth. We performed homozygosity mapping in three unrelated consanguineous Pakistani families and localized the syndrome to a region in chromosome 9. Mutational analysis of candidate genes in the region revealed that all affected children harbored homozygous missense mutations (c.662C>G [p.Pro221Arg], c...... for the treatment of craniosynostosis....

Analysis of HLA-A antigens and C282Y and H63D mutations of the HFE gene in Brazilian patients with hemochromatosis

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Bittencourt P.L.

2002-01-01

Full Text Available The hemochromatosis gene, HFE, is located on chromosome 6 in close proximity to the HLA-A locus. Most Caucasian patients with hereditary hemochromatosis (HH are homozygous for HLA-A3 and for the C282Y mutation of the HFE gene, while a minority are compound heterozygotes for C282Y and H63D. The prevalence of these mutations in non-Caucasian patients with HH is lower than expected. The objective of the present study was to evaluate the frequencies of HLA-A antigens and the C282Y and H63D mutations of the HFE gene in Brazilian patients with HH and to compare clinical and laboratory profiles of C282Y-positive and -negative patients with HH. The frequencies of HLA-A and C282Y and H63D mutations were determined by PCR-based methods in 15 male patients (median age 44 (20-72 years with HH. Eight patients (53% were homozygous and one (7% was heterozygous for the C282Y mutation. None had compound heterozygosity for C282Y and H63D mutations. All but three C282Y homozygotes were positive for HLA-A3 and three other patients without C282Y were shown to be either heterozygous (N = 2 or homozygous (N = 1 for HLA-A3. Patients homozygous for the C282Y mutation had higher ferritin levels and lower age at onset, but the difference was not significant. The presence of C282Y homozygosity in roughly half of the Brazilian patients with HH, together with the findings of HLA-A homozygosity in C282Y-negative subjects, suggest that other mutations in the HFE gene or in other genes involved in iron homeostasis might also be linked to HH in Brazil.

Identification of a Novel Dentin Matrix Protein-1 (DMP-1) Mutation and Dental Anomalies in a Kindred with Autosomal Recessive Hypophosphatemia

OpenAIRE

Turan, Serap; Aydin, Cumhur; Bereket, Abdullah; Akcay, Teoman; Güran, Tülay; Yaralioglu, Betul Akmen; Bastepe, Murat; Jüppner, Harald

2009-01-01

An autosomal recessive form of hypophosphatemia (ARHP) was recently shown to be caused by homozygous mutations in DMP1, the gene encoding dentin matrix protein-1 (DMP-1), a non-collagenous bone matrix protein with an important role in the development and mineralization of bone and teeth. Here, we report a previously not reported consanguineous ARHP kindred in which the three affected individuals carry a novel homozygous DMP-1 mutation. The index case presented at the age of 3 years with bowin...

How much do we know about spontaneous human mutation rates

Energy Technology Data Exchange (ETDEWEB)

Crow, J.F. (Univ. of Wisconsin, Madison, WI (United States))

1993-01-01

The much larger number of cell divisions between zygote and sperm than between zygote and egg, the increased age of fathers of children with new dominant mutations, and the greater evolution rate of pseudogenes on the Y chromosome than of those on autosomes all point to a much higher mutation rate in human males than in females, as first pointed out by Haldane in his classical study of X-linked hemophilia. The age of the father is the main factor determining the human spontaneous mutation rate, and probably the total mutation rate. The total mutation rate in Drosophila males of genes causing minor reduction in viability is at least 0.4 per sperm and may be considerably higher. The great mutation load implied by a rate of [approx] 1 per zygote can be greatly ameliorated by quasi-transition selection. Corresponding data are not available for the human population. The evolution rate of pseudogenes in primates suggests some 10[sup 2] new mutations per zygote. Presumably the overwhelming majority of these are neutral, but even the approximate fraction is not known. Statistical evidence in Drosophilia shows that mutations with minor effects cause about the same heterozygous impairment of fitness as those that are lethal when homozygous. The magnitude of heterozygous effect is such that almost all mutant genes are eliminated as heterozygotes before ever becoming homozygous. Although quantitative data in the human species are lacking, anecdotal information supports the conclusion that partial dominance is the rule here as well. This suggests that if the human mutation rate were increased or decreased, the effects would be spread over a period of 50-100 generations. 31 refs., 3 figs., 2 tabs.

Cell surface fucosylation does not affect development of colon tumors in mice with germline Smad3 mutation

Science.gov (United States)

Domino, Steven E.; Karnak, David M.; Hurd, Elizabeth A.

2006-01-01

Background/Aims: Neoplasia-related alterations in cell surface α(1,2)fucosylated glycans have been reported in multiple tumors including colon, pancreas, endometrium, cervix, bladder, lung, and choriocarcinoma. Spontaneous colorectal tumors from mice with a germline null mutation of transforming growth factor-β signaling gene Smad3 (Madh3) were tested for α(1,2)fucosylated glycan expression. Methods: Ulex Europaeus Agglutinin-I lectin staining, fucosyltransferase gene northern blot analysis, and a cross of mutant mice with Fut2 and Smad3 germline mutations were performed. Results: Spontaneous colorectal tumors from Smad3 (-/-) homozygous null mice were found to express α(1,2)fucosylated glycans in an abnormal pattern compared to adjacent nonneoplastic colon. Northern blot analysis of α(1,2)fucosyltransferase genes Fut1 and Fut2 revealed that Fut2, but not Fut1, steady-state mRNA levels were significantly increased in tumors relative to adjacent normal colonic mucosa. Mutant mice with a Fut2-inactivating germline mutation were crossed with Smad3 targeted mice. In Smad3 (-/-)/Fut2 (-/-) double knock-out mice, UEA-I lectin staining was eliminated from colon and colon tumors, however, the number and size of tumors present by 24 weeks of age did not vary regardless of the Fut2 genotype. Conclusions: In this model of colorectal cancer, cell surface α(1,2)fucosylation does not affect development of colon tumors. PMID:17264540

HFE gene C282Y, H63D and S65C mutations frequency in the Transylvania region, Romania.

Science.gov (United States)

Trifa, Adrian P; Popp, Radu A; Militaru, Mariela S; Farcaş, Marius F; Crişan, Tania O; Gana, Ionuţ; Cucuianu, Andrei; Pop, Ioan V

2012-06-01

HFE-associated haemochromatosis is one of the most frequent autosomal recessive disorders in the Caucasian population. Although most of the cases are homozygous individuals for the C282Y mutation, another two mutations, H63D and S65C, have been reported to be associated with milder forms of the disease. This study was a first attempt to evaluate the distribution of these HFE gene mutations in the Transylvania region. Two-hundred and twenty-five healthy, unrelated volunteers originating from the Transylvania region, Romania, were screened for the HFE gene C282Y, H63D and S65C mutations, using molecular genetics assays (Polymerase Chain Reaction-Restriction Fragments Length Polymorphism). For the C282Y mutation, 7 heterozygotes (3.1%) were found, but no homozygous individual. In the case of the H63D mutation, 40 heterozygotes (17.8%) and 4 homozygotes (1.75%) for the mutant allele were evidenced. We found a compound heterozygous genotype (C282Y/H63D) in one individual (0.45%). Thus, the allele frequencies of the C282Y and H63D were 1.75% and 10.9%, respectively. Three individuals (1.3%) were found to harbour the S65C mutation in a heterozygous state, but none in a homozygous state: the allele frequency of the mutant allele was 0.75%. The distribution of the HFE gene C282Y, H63D and S65C mutations found in our group matches the tendencies observed in other European countries: a decreasing gradient from Northern to Southern Europe for the C282Y mutation; high frequency for the H63D mutation, and low frequency for the S65C mutation in most of the countries.

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.

Normal X-inactivation mosaicism in corneas of heterozygous FlnaDilp2/+ female mice--a model of human Filamin A (FLNA diseases

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Douvaras Panagiotis

2012-02-01

Full Text Available Abstract Background Some abnormalities of mouse corneal epithelial maintenance can be identified by the atypical mosaic patterns they produce in X-chromosome inactivation mosaics and chimeras. Human FLNA/+ females, heterozygous for X-linked, filamin A gene (FLNA mutations, display a range of disorders and X-inactivation mosaicism is sometimes quantitatively unbalanced. FlnaDilp2/+ mice, heterozygous for an X-linked filamin A (Flna nonsense mutation have variable eye, skeletal and other abnormalities, but X-inactivation mosaicism has not been investigated. The aim of this study was to determine whether X-inactivation mosaicism in the corneal epithelia of FlnaDilp2/+ mice was affected in any way that might predict abnormal corneal epithelial maintenance. Results X-chromosome inactivation mosaicism was studied in the corneal epithelium and a control tissue (liver of FlnaDilp2/+ and wild-type (WT female X-inactivation mosaics, hemizygous for the X-linked, LacZ reporter H253 transgene, using β-galactosidase histochemical staining. The corneal epithelia of FlnaDilp2/+ and WT X-inactivation mosaics showed similar radial, striped patterns, implying epithelial cell movement was not disrupted in FlnaDilp2/+ corneas. Corrected stripe numbers declined with age overall (but not significantly for either genotype individually, consistent with previous reports suggesting an age-related reduction in stem cell function. Corrected stripe numbers were not reduced in FlnaDilp2/+ compared with WT X-inactivation mosaics and mosaicism was not significantly more unbalanced in the corneal epithelia or livers of FlnaDilp2/+ than wild-type Flna+/+ X-inactivation mosaics. Conclusions Mosaic analysis identified no major effect of the mouse FlnaDilp2 mutation on corneal epithelial maintenance or the balance of X-inactivation mosaicism in the corneal epithelium or liver.

Novel ITGB6 mutation in autosomal recessive amelogenesis imperfecta.

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Seymen, F; Lee, K-E; Koruyucu, M; Gencay, K; Bayram, M; Tuna, E B; Lee, Z H; Kim, J-W

2015-05-01

Hereditary defects in tooth enamel formation, amelogenesis imperfecta (AI), can be non-syndromic or syndromic phenotype. Integrins are signaling proteins that mediate cell-cell and cell-extracellular matrix communication, and their involvement in tooth development is well known. The purposes of this study were to identify genetic cause of an AI family and molecular pathogenesis underlying defective enamel formation. We recruited a Turkish family with isolated AI and performed mutational analyses to clarify the underlying molecular genetic etiology. Autozygosity mapping and exome sequencing identified a novel homozygous ITGB6 transversion mutation in exon 4 (c.517G>C, p.Gly173Arg). The glycine at this position in the middle of the βI-domain is conserved among a wide range of vertebrate orthologs and human paralogs. Clinically, the enamel was generally thin and pitted with pigmentation. Thicker enamel was noted at the cervical area of the molars. In this study, we identified a novel homozygous ITGB6 mutation causing isolated AI, and this advances the understanding of normal and pathologic enamel development. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A Clinical, Neuropathological and Genetic Study of Homozygous A467T POLG-Related Mitochondrial Disease.

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Sanjeev Rajakulendran

Full Text Available Mutations in the nuclear gene POLG (encoding the catalytic subunit of DNA polymerase gamma are an important cause of mitochondrial disease. The most common POLG mutation, A467T, appears to exhibit considerable phenotypic heterogeneity. The mechanism by which this single genetic defect results in such clinical diversity remains unclear. In this study we evaluate the clinical, neuropathological and mitochondrial genetic features of four unrelated patients with homozygous A467T mutations. One patient presented with the severe and lethal Alpers-Huttenlocher syndrome, which was confirmed on neuropathology, and was found to have a depletion of mitochondrial DNA (mtDNA. Of the remaining three patients, one presented with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS, one with a phenotype in the Myoclonic Epilepsy, Myopathy and Sensory Ataxia (MEMSA spectrum and one with Sensory Ataxic Neuropathy, Dysarthria and Ophthalmoplegia (SANDO. All three had secondary accumulation of multiple mtDNA deletions. Complete sequence analysis of muscle mtDNA using the MitoChip resequencing chip in all four cases demonstrated significant variation in mtDNA, including a pathogenic MT-ND5 mutation in one patient. These data highlight the variable and overlapping clinical and neuropathological phenotypes and downstream molecular defects caused by the A467T mutation, which may result from factors such as the mtDNA genetic background, nuclear genetic modifiers and environmental stressors.

Congenital myopathy is caused by mutation of HACD1

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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...

To Screen Inactivation Mutation of Exon 1 of FSHR Gene in Polycystic Ovarian Syndrome: A South Indian Cohort Study

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Sekar, Nishu; Yeole, Samiksha; Pradeep, Rashmi; Prabhu, Yogamaya D.; Renu, Kaviyarasi; Ramgir, Shalaka S.; Abilash, V. G.

2017-11-01

Polycystic ovary syndrome is an endocrine disorder. Irregular menstrual cycle, acne, facial hair and elevated androgen levels are the most common signs for PCOS. PCOS has an estimated prevalence of 4-12% among reproductive age women, thus making it a forerunner in female infertility. FSHR plays an important role in FSH signaling pathway making it an important gene for PCOS. In this study, we aim to focus on any association between the FSHR gene and PCOS. Our study was to evaluate any polymorphism of exon 1 of FSHR gene associated with PCOS.PCR-RFLP technique was performed on the PCOS samples. Hormonal changes were found in the patients. Exon 1 inactivation mutation of FSHR gene was not observed in the patient sample. A study of this association needs to be done using large sample size.

Homozygous missense mutation in the LMAN2L gene segregates with intellectual disability in a large consanguineous Pakistani family.

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Rafiullah, Rafiullah; Aslamkhan, Muhammad; Paramasivam, Nagarajan; Thiel, Christian; Mustafa, Ghulam; Wiemann, Stefan; Schlesner, Matthias; Wade, Rebecca C; Rappold, Gudrun A; Berkel, Simone

2016-02-01

Intellectual disability (ID) is a neurodevelopmental disorder affecting 1%-3% of the population worldwide. It is characterised by high phenotypic and genetic heterogeneity and in most cases the underlying cause of the disorder is unknown. In our study we investigated a large consanguineous family from Baluchistan, Pakistan, comprising seven affected individuals with a severe form of autosomal recessive ID (ARID) and epilepsy, to elucidate a putative genetic cause. Whole exome sequencing (WES) of a trio, including a child with ID and epilepsy and its healthy parents that were part of this large family, revealed a homozygous missense variant p.R53Q in the lectin mannose-binding 2-like (LMAN2L) gene. This homozygous variant was co-segregating in the family with the phenotype of severe ID and infantile epilepsy; unaffected family members were heterozygous variant carriers. The variant was predicted to be pathogenic by five different in silico programmes and further three-dimensional structure modelling of the protein suggests that variant p.R53Q may impair protein-protein interaction. LMAN2L (OMIM: 609552) encodes for the lectin, mannose-binding 2-like protein which is a cargo receptor in the endoplasmic reticulum important for glycoprotein transport. Genome-wide association studies have identified an association of LMAN2L to different neuropsychiatric disorders. This is the first report linking LMAN2L to a phenotype of severe ARID and seizures, indicating that the deleterious homozygous p.R53Q variant very likely causes the disorder. 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/

Complex phenotype of dyskeratosis congenita and mood dysregulation with novel homozygous RTEL1 and TPH1 variants.

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Ungar, Rachel A; Giri, Neelam; Pao, Maryland; Khincha, Payal P; Zhou, Weiyin; Alter, Blanche P; Savage, Sharon A

2018-06-01

Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome caused by germline mutations in telomere biology genes. Patients have extremely short telomeres for their age and a complex phenotype including oral leukoplakia, abnormal skin pigmentation, and dysplastic nails in addition to bone marrow failure, pulmonary fibrosis, stenosis of the esophagus, lacrimal ducts and urethra, developmental anomalies, and high risk of cancer. We evaluated a patient with features of DC, mood dysregulation, diabetes, and lack of pubertal development. Family history was not available but genome-wide genotyping was consistent with consanguinity. Whole exome sequencing identified 82 variants of interest in 80 genes based on the following criteria: homozygous, <0.1% minor allele frequency in public and in-house databases, nonsynonymous, and predicted deleterious by multiple in silico prediction programs. Six genes were identified likely contributory to the clinical presentation. The cause of DC is likely due to homozygous splice site variants in regulator of telomere elongation helicase 1, a known DC and telomere biology gene. A homozygous, missense variant in tryptophan hydroxylase 1 may be clinically important as this gene encodes the rate limiting step in serotonin biosynthesis, a biologic pathway connected with mood disorders. Four additional genes (SCN4A, LRP4, GDAP1L1, and SPTBN5) had rare, missense homozygous variants that we speculate may contribute to portions of the clinical phenotype. This case illustrates the value of conducting detailed clinical and genomic evaluations on rare patients in order to identify new areas of research into the functional consequences of rare variants and their contribution to human disease. © 2018 Wiley Periodicals, Inc.

Mucopolysaccharidosis type I: molecular characteristics of two novel alpha-L-iduronidase mutations in Tunisian patients

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Chahed Henda

2011-06-01

Full Text Available Abstract Background Mucopolysaccharidosis type I (MPS I is an autosomal storage disease resulting from defective activity of the enzyme α-L-iduronidase (IDUA. This glycosidase is involved in the degradation of heparan sulfate and dermatan sulfate. MPS I has severe and milder phenotypic subtypes. Aim of study: This study was carried out on six newly collected MPS I patients recruited from many regions of Tunisia. Patients and methods: Mutational analysis of the IDUA gene in unrelated MPS I families was performed by sequencing the exons and intron-exon junctions of IDUA gene. Results Two novel IDUA mutations, p.L530fs (1587_1588 insGC in exon 11 and p.F177S in exon 5 and two previously reported mutations p.P533R and p.Y581X were detected. The patient in family 1 who has the Hurler phenotype was homozygous for the previously described nonsense mutation p.Y581X. The patient in family 2 who also has the Hurler phenotype was homozygous for the novel missense mutation p.F177S. The three patients in families 3, 5 and 6 were homozygous for the p.P533R mutation. The patient in family 4 was homozygous for the novel small insertion 1587_1588 insGC. In addition, eighteen known and one unknown IDUA polymorphisms were identified. Conclusion The identification of these mutations should facilitate prenatal diagnosis and counseling for MPS I in Tunisia. Background Mucopolysaccharidosis type I (MPS I is an autosomal recessive lysosomal storage disorder caused by the deficient activity of the enzyme of α-L-iduronidase (IDUA, EC 3.2.1.76. This glycosidase is involved in the degradation of heparan sulfate and dermatan sulfate. The clinical phenotype of MPS I ranges from the very severe in Hurler syndrome (MPS IH to the relatively benign in Scheie syndrome (MPS IS, with an intermediate phenotype designated Hurler/Scheie (MPS IH/S 1. Isolation of complementary and genomic DNAs encoding human α -L- iduronidase 23 have enable the identification of mutations underlying

Heart-specific expression of laminopathic mutations in transgenic zebrafish.

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Verma, Ajay D; Parnaik, Veena K

2017-07-01

Lamins are key determinants of nuclear organization and function in the metazoan nucleus. Mutations in human lamin A cause a spectrum of genetic diseases that affect cardiac muscle and skeletal muscle as well as other tissues. A few laminopathies have been modeled using the mouse. As zebrafish is a well established model for the study of cardiac development and disease, we have investigated the effects of heart-specific lamin A mutations in transgenic zebrafish. We have developed transgenic lines of zebrafish expressing conserved lamin A mutations that cause cardiac dysfunction in humans. Expression of zlamin A mutations Q291P and M368K in the heart was driven by the zebrafish cardiac troponin T2 promoter. Homozygous mutant embryos displayed nuclear abnormalities in cardiomyocyte nuclei. Expression analysis showed the upregulation of genes involved in heart regeneration in transgenic mutant embryos and a cell proliferation marker was increased in adult heart tissue. At the physiological level, there was deviation of up to 20% from normal heart rate in transgenic embryos expressing mutant lamins. Adult homozygous zebrafish were fertile and did not show signs of early mortality. Our results suggest that transgenic zebrafish models of heart-specific laminopathies show cardiac regeneration and moderate deviations in heart rate during embryonic development. © 2017 International Federation for Cell Biology.

Expression of the p16{sup INK4a} tumor suppressor gene in rodent lung tumors

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Swafford, D.S.; Tesfaigzi, J.; Belinsky, S.A.

1995-12-01

Aberrations on the short arm of chromosome 9 are among the earliest genetic changes in human cancer. p16{sup INK4a} is a candidate tumor suppressor gene that lies within human 9p21, a chromosome region associated with frequent loss of heterozygosity in human lung tumors. The p16{sup INK4a} protein functions as an inhibitor of cyclin D{sub 1}-dependent kinases that phosphorylate the retinoblastoma (Rb) tumor suppressor gene product enabling cell-cycle progression. Thus, overexpression of cyclin D{sub 1}, mutation of cyclin-dependent kinase genes, or loss of p16{sup INK4a} function, can all result in functional inactivation of Rb. Inactivation of Rb by mutation or deletion can result in an increase in p16{sup INK4a} transcription, suggesting that an increased p16{sup INK4a} expression in a tumor cell signals dysfunction of the pathway. The p16{sup (INK4a)} gene, unlike some tumor suppressor genes, is rarely inactivated by mutation. Instead, the expression of this gene is suppressed in some human cancers by hypermethylation of the CpG island within the first exon or by homozygous deletion: 686. Chromosome losses have been observed at 9p21 syntenic loci in tumors of the mouse and rat, two species often used as animal models for pulmonary carcinogenesis. Expression of p16{sup INK4a} is lost in some mouse tumor cell lines, often due to homozygous deletion. These observations indicate that p16{sup INK4a} dysfunction may play a role in the development of neoplasia in rodents as well as humans. The purpose of the current investigation was to define the extent to which p16{sup INK4a} dysfunction contributes to the development of rodent lung tumors and to determine the mechanism of inactivation of the gene. There is no evidence to suggest a loss of function of the p16{sup INK4a} tumor suppressor gene in these primary murine lung tumors by mutation, deletion, or methylation.

Mutations and epimutations in the origin of cancer

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Peltomaeki, Paeivi, E-mail: Paivi.Peltomaki@Helsinki.Fi

2012-02-15

Cancer is traditionally viewed as a disease of abnormal cell proliferation controlled by a series of mutations. Mutations typically affect oncogenes or tumor suppressor genes thereby conferring growth advantage. Genomic instability facilitates mutation accumulation. Recent findings demonstrate that activation of oncogenes and inactivation of tumor suppressor genes, as well as genomic instability, can be achieved by epigenetic mechanisms as well. Unlike genetic mutations, epimutations do not change the base sequence of DNA and are potentially reversible. Similar to genetic mutations, epimutations are associated with specific patterns of gene expression that are heritable through cell divisions. Knudson's hypothesis postulates that inactivation of tumor suppressor genes requires two hits, with the first hit occurring either in somatic cells (sporadic cancer) or in the germline (hereditary cancer) and the second one always being somatic. Studies on hereditary and sporadic forms of colorectal carcinoma have made it evident that, apart from genetic mutations, epimutations may serve as either hit or both. Furthermore, recent next-generation sequencing studies show that epigenetic genes, such as those encoding histone modifying enzymes and subunits for chromatin remodeling systems, are themselves frequent targets of somatic mutations in cancer and can act like tumor suppressor genes or oncogenes. This review discusses genetic vs. epigenetic origin of cancer, including cancer susceptibility, in light of recent discoveries. Situations in which mutations and epimutations occur to serve analogous purposes are highlighted.

Establishment of a Conditionally Immortalized Wilms Tumor Cell Line with a Homozygous WT1 Deletion within a Heterozygous 11p13 Deletion and UPD Limited to 11p15.

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Artur Brandt

Full Text Available We describe a stromal predominant Wilms tumor with focal anaplasia and a complex, tumor specific chromosome 11 aberration: a homozygous deletion of the entire WT1 gene within a heterozygous 11p13 deletion and an additional region of uniparental disomy (UPD limited to 11p15.5-p15.2 including the IGF2 gene. The tumor carried a heterozygous p.T41A mutation in CTNNB1. Cells established from the tumor carried the same chromosome 11 aberration, but a different, homozygous p.S45Δ CTNNB1 mutation. Uniparental disomy (UPD 3p21.3pter lead to the homozygous CTNNB1 mutation. The tumor cell line was immortalized using the catalytic subunit of human telomerase (hTERT in conjunction with a novel thermolabile mutant (U19dl89-97tsA58 of SV40 large T antigen (LT. This cell line is cytogenetically stable and can be grown indefinitely representing a valuable tool to study the effect of a complete lack of WT1 in tumor cells. The origin/fate of Wilms tumors with WT1 mutations is currently poorly defined. Here we studied the expression of several genes expressed in early kidney development, e.g. FOXD1, PAX3, SIX1, OSR1, OSR2 and MEIS1 and show that these are expressed at similar levels in the parental and the immortalized Wilms10 cells. In addition the limited potential for muscle/ osteogenic/ adipogenic differentiation similar to all other WT1 mutant cell lines is also observed in the Wilms10 tumor cell line and this is retained in the immortalized cells. In summary these Wilms10 cells are a valuable model system for functional studies of WT1 mutant cells.

Establishment of a Conditionally Immortalized Wilms Tumor Cell Line with a Homozygous WT1 Deletion within a Heterozygous 11p13 Deletion and UPD Limited to 11p15

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Brandt, Artur; Löhers, Katharina; Beier, Manfred; Leube, Barbara; de Torres, Carmen; Mora, Jaume; Arora, Parineeta; Jat, Parmjit S.; Royer-Pokora, Brigitte

2016-01-01

We describe a stromal predominant Wilms tumor with focal anaplasia and a complex, tumor specific chromosome 11 aberration: a homozygous deletion of the entire WT1 gene within a heterozygous 11p13 deletion and an additional region of uniparental disomy (UPD) limited to 11p15.5-p15.2 including the IGF2 gene. The tumor carried a heterozygous p.T41A mutation in CTNNB1. Cells established from the tumor carried the same chromosome 11 aberration, but a different, homozygous p.S45Δ CTNNB1 mutation. Uniparental disomy (UPD) 3p21.3pter lead to the homozygous CTNNB1 mutation. The tumor cell line was immortalized using the catalytic subunit of human telomerase (hTERT) in conjunction with a novel thermolabile mutant (U19dl89-97tsA58) of SV40 large T antigen (LT). This cell line is cytogenetically stable and can be grown indefinitely representing a valuable tool to study the effect of a complete lack of WT1 in tumor cells. The origin/fate of Wilms tumors with WT1 mutations is currently poorly defined. Here we studied the expression of several genes expressed in early kidney development, e.g. FOXD1, PAX3, SIX1, OSR1, OSR2 and MEIS1 and show that these are expressed at similar levels in the parental and the immortalized Wilms10 cells. In addition the limited potential for muscle/ osteogenic/ adipogenic differentiation similar to all other WT1 mutant cell lines is also observed in the Wilms10 tumor cell line and this is retained in the immortalized cells. In summary these Wilms10 cells are a valuable model system for functional studies of WT1 mutant cells. PMID:27213811

Progressive cerebellar atrophy and polyneuropathy: expanding the spectrum of PNKP mutations

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Poulton, C.; Oegema, R.; Heijsman, D.; Hoogeboom, J.; Schot, R.; Stroink, H.; Willemsen, M.A.A.P.; Verheijen, F.W.; Spek, P. van der; Kremer, A.; Mancini, G.M.S.

2013-01-01

We present a neurodegenerative disorder starting in early childhood of two brothers consisting of severe progressive polyneuropathy, severe progressive cerebellar atrophy, microcephaly, mild epilepsy, and intellectual disability. The cause of this rare syndrome was found to be a homozygous mutation

Multi-kilobase homozygous targeted gene replacement in human induced pluripotent stem cells.

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Byrne, Susan M; Ortiz, Luis; Mali, Prashant; Aach, John; Church, George M

2015-02-18

Sequence-specific nucleases such as TALEN and the CRISPR/Cas9 system have so far been used to disrupt, correct or insert transgenes at precise locations in mammalian genomes. We demonstrate efficient 'knock-in' targeted replacement of multi-kilobase genes in human induced pluripotent stem cells (iPSC). Using a model system replacing endogenous human genes with their mouse counterpart, we performed a comprehensive study of targeting vector design parameters for homologous recombination. A 2.7 kilobase (kb) homozygous gene replacement was achieved in up to 11% of iPSC without selection. The optimal homology arm length was around 2 kb, with homology length being especially critical on the arm not adjacent to the cut site. Homologous sequence inside the cut sites was detrimental to targeting efficiency, consistent with a synthesis-dependent strand annealing (SDSA) mechanism. Using two nuclease sites, we observed a high degree of gene excisions and inversions, which sometimes occurred more frequently than indel mutations. While homozygous deletions of 86 kb were achieved with up to 8% frequency, deletion frequencies were not solely a function of nuclease activity and deletion size. Our results analyzing the optimal parameters for targeting vector design will inform future gene targeting efforts involving multi-kilobase gene segments, particularly in human iPSC. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Co-occurrence of point mutations in the voltage-gated sodium channel of pyrethroid-resistant Aedes aegypti populations in Myanmar.

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Kawada, Hitoshi; Oo, Sai Zaw Min; Thaung, Sein; Kawashima, Emiko; Maung, Yan Naung Maung; Thu, Hlaing Myat; Thant, Kyaw Zin; Minakawa, Noboru

2014-01-01

Single amino acid substitutions in the voltage-gated sodium channel associated with pyrethroid resistance constitute one of the main causative factors of knockdown resistance in insects. The kdr gene has been observed in several mosquito species; however, point mutations in the para gene of Aedes aegypti populations in Myanmar have not been fully characterized. The aim of the present study was to determine the types and frequencies of mutations in the para gene of Aedes aegypti collected from used tires in Yangon City, Myanmar. We determined high pyrethroid resistance in Aedes aegypti larvae at all collection sites in Yangon City, by using a simplified knockdown bioassay. We showed that V1016G and S989P mutations were widely distributed, with high frequencies (84.4% and 78.8%, respectively). By contrast, we were unable to detect I1011M (or I1011V) or L1014F mutations. F1534C mutations were also widely distributed, but with a lower frequency than the V1016G mutation (21.2%). High percentage of co-occurrence of the homozygous V1016G/S989P mutations was detected (65.7%). Additionally, co-occurrence of homozygous V1016G/F1534C mutations (2.9%) and homozygous V1016G/F1534C/S989P mutations (0.98%) were detected in the present study. Pyrethroid insecticides were first used for malaria control in 1992, and have since been constantly used in Myanmar. This intensive use may explain the strong selection pressure toward Aedes aegypti, because this mosquito is generally a domestic and endophagic species with a preference for indoor breeding. Extensive use of DDT for malaria control before the use of this chemical was banned may also explain the development of pyrethroid resistance in Aedes aegypti.

Co-occurrence of Point Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Aedes aegypti Populations in Myanmar

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Kawada, Hitoshi; Oo, Sai Zaw Min; Thaung, Sein; Kawashima, Emiko; Maung, Yan Naung Maung; Thu, Hlaing Myat; Thant, Kyaw Zin; Minakawa, Noboru

2014-01-01

Background Single amino acid substitutions in the voltage-gated sodium channel associated with pyrethroid resistance constitute one of the main causative factors of knockdown resistance in insects. The kdr gene has been observed in several mosquito species; however, point mutations in the para gene of Aedes aegypti populations in Myanmar have not been fully characterized. The aim of the present study was to determine the types and frequencies of mutations in the para gene of Aedes aegypti collected from used tires in Yangon City, Myanmar. Methodology/Principal Findings We determined high pyrethroid resistance in Aedes aegypti larvae at all collection sites in Yangon City, by using a simplified knockdown bioassay. We showed that V1016G and S989P mutations were widely distributed, with high frequencies (84.4% and 78.8%, respectively). By contrast, we were unable to detect I1011M (or I1011V) or L1014F mutations. F1534C mutations were also widely distributed, but with a lower frequency than the V1016G mutation (21.2%). High percentage of co-occurrence of the homozygous V1016G/S989P mutations was detected (65.7%). Additionally, co-occurrence of homozygous V1016G/F1534C mutations (2.9%) and homozygous V1016G/F1534C/S989P mutations (0.98%) were detected in the present study. Conclusions/Significance Pyrethroid insecticides were first used for malaria control in 1992, and have since been constantly used in Myanmar. This intensive use may explain the strong selection pressure toward Aedes aegypti, because this mosquito is generally a domestic and endophagic species with a preference for indoor breeding. Extensive use of DDT for malaria control before the use of this chemical was banned may also explain the development of pyrethroid resistance in Aedes aegypti. PMID:25077956

The Dwarfs of Sindh: severe growth hormone (GH) deficiency caused by a mutation in the GH-releasing hormone receptor gene.

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Baumann, G; Maheshwari, H

1997-11-01

We report the discovery of a cluster of severe familial dwarfism in two villages in the Province of Sindh in Pakistan. Dwarfism is proportionate and occurs in members of a kindred with a high degree of consanguinity. Only the last generation is affected, with the oldest dwarf being 28 years old. The mode of inheritance is autosomal recessive. Phenotype analysis and endocrine testing revealed isolated growth hormone deficiency (GHD) as the reason for growth failure. Linkage analysis for the loci of several candidate genes yielded a high lod score for the growth hormone-releasing hormone receptor (GHRH-R) locus on chromosome 7. Amplification and sequencing of the GHRH-R gene in affected subjects demonstrated an amber nonsense mutation (GAG-->TAG; Glu50-->Stop) in exon 3. The mutation, in its homozygous form, segregated 100% with the dwarf phenotype. It predicts a truncation of the GHRH-R in its extracellular domain, which is likely to result in a severely disabled or non-existent receptor protein. Subjects who are heterozygous for the mutation show mild biochemical abnormalities in the growth hormone-releasing hormone (GHRH)--growth hormone--insulin-like growth factor axis, but have only minimal or no growth retardation. The occurrence of an offspring of two dwarfed parents indicates that the GHRH-R is not necessary for fertility in either sex. We conclude that Sindh dwarfism is caused by an inactivating mutation in the GHRH-R gene, resulting in the inability to transmit a GHRH signal and consequent severe isolated GHD.

Next generation sequencing of Cytokeratin 20-negative Merkel cell carcinoma reveals ultraviolet-signature mutations and recurrent TP53 and RB1 inactivation.

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Harms, Paul W; Collie, Angela M B; Hovelson, Daniel H; Cani, Andi K; Verhaegen, Monique E; Patel, Rajiv M; Fullen, Douglas R; Omata, Kei; Dlugosz, Andrzej A; Tomlins, Scott A; Billings, Steven D

2016-03-01

Merkel cell carcinoma is a rare but highly aggressive cutaneous neuroendocrine carcinoma. Cytokeratin 20 (CK20) is expressed in ~95% of Merkel cell carcinomas and is useful for distinction from morphologically similar entities including metastatic small-cell lung carcinoma. Lack of CK20 expression may make diagnosis of Merkel cell carcinoma more challenging, and has unknown biological significance. Approximately 80% of CK20-positive Merkel cell carcinomas are associated with the oncogenic Merkel cell polyomavirus. Merkel cell carcinomas lacking Merkel cell polyomavirus display distinct genetic changes from Merkel cell polyomavirus-positive Merkel cell carcinoma, including RB1 inactivating mutations. Unlike CK20-positive Merkel cell carcinoma, the majority of CK20-negative Merkel cell carcinomas are Merkel cell polyomavirus-negative, suggesting CK20-negative Merkel cell carcinomas predominantly arise through virus-independent pathway(s) and may harbor additional genetic differences from conventional Merkel cell carcinoma. Hence, we analyzed 15 CK20-negative Merkel cell carcinoma tumors (10 Merkel cell polyomavirus-negative, four Merkel cell polyomavirus-positive, and one undetermined) using the Ion Ampliseq Comprehensive Cancer Panel, which assesses copy number alterations and mutations in 409 cancer-relevant genes. Twelve tumors displayed prioritized high-level chromosomal gains or losses (average 1.9 per tumor). Non-synonymous high-confidence somatic mutations were detected in 14 tumors (average 11.9 per tumor). Assessing all somatic coding mutations, an ultraviolet-signature mutational profile was present, and more prevalent in Merkel cell polyomavirus-negative tumors. Recurrent deleterious tumor suppressor mutations affected TP53 (9/15, 60%), RB1 (3/15, 20%), and BAP1 (2/15, 13%). Oncogenic activating mutations included PIK3CA (3/15, 20%), AKT1 (1/15, 7%) and EZH2 (1/15, 7%). In conclusion, CK20-negative Merkel cell carcinoma display overlapping genetic changes

Next Generation Sequencing of Cytokeratin 20-Negative Merkel Cell Carcinoma Reveals Ultraviolet Signature Mutations and Recurrent TP53 and RB1 Inactivation

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Harms, Paul W.; Collie, Angela M. B.; Hovelson, Daniel H.; Cani, Andi K.; Verhaegen, Monique E.; Patel, Rajiv M.; Fullen, Douglas R.; Omata, Kei; Dlugosz, Andrzej A.; Tomlins, Scott A.; Billings, Steven D.

2016-01-01

Merkel cell carcinoma is a rare but highly aggressive cutaneous neuroendocrine carcinoma. Cytokeratin-20 (CK20) is expressed in approximately 95% of Merkel cell carcinomas and is useful for distinction from morphologically similar entities including metastatic small cell lung carcinoma. Lack of CK20 expression may make diagnosis of Merkel cell carcinoma more challenging, and has unknown biological significance. Approximately 80% of CK20-positive Merkel cell carcinomas are associated with the oncogenic Merkel cell polyomavirus. Merkel cell carcinomas lacking Merkel cell polyomavirus display distinct genetic changes from Merkel cell polyomavirus-positive Merkel cell carcinoma, including RB1 inactivating mutations. Unlike CK20-positive Merkel cell carcinoma, the majority of CK20-negative Merkel cell carcinomas are Merkel cell polyomavirus-negative, suggesting CK20-negative Merkel cell carcinomas predominantly arise through virus-independent pathway(s) and may harbor additional genetic differences from conventional Merkel cell carcinoma. Hence, we analyzed 15 CK20-negative Merkel cell carcinoma tumors (ten Merkel cell polyomavirus-negative, four Merkel cell polyomavirus-positive, and one undetermined) using the Ion Ampliseq Comprehensive Cancer Panel, which assesses copy number alterations and mutations in 409 cancer-relevant genes. Twelve tumors displayed prioritized high-level chromosomal gains or losses (average 1.9 per tumor). Non-synonymous high confidence somatic mutations were detected in 14 tumors (average 11.9 per tumor). Assessing all somatic coding mutations, an ultraviolet-signature mutational profile was present, and more prevalent in Merkel cell polyomavirus-negative tumors. Recurrent deleterious tumor suppressor mutations affected TP53 (9/15, 60%), RB1 (3/15, 20%), and BAP1 (2/15, 13%). Oncogenic activating mutations included PIK3CA (3/15, 20%), AKT1 (1/15, 7%)) and EZH2 (1/15, 7%). In conclusion, CK20-negative Merkel cell carcinoma display overlapping

Cortical atrophy and hypofibrinogenemia due to FGG and TBCD mutations in a single family: a case report.

Science.gov (United States)

Stephen, Joshi; Nampoothiri, Sheela; Vinayan, K P; Yesodharan, Dhanya; Remesh, Preetha; Gahl, William A; Malicdan, May Christine V

2018-05-16

Blended phenotypes or co-occurrence of independent phenotypically distinct conditions are extremely rare and are due to coincidence of multiple pathogenic mutations, especially due to consanguinity. Hereditary fibrinogen deficiencies result from mutations in the genes FGA, FGB, and FGG, encoding the three different polypeptide chains that comprise fibrinogen. Neurodevelopmental abnormalities have not been associated with fibrinogen deficiencies. In this study, we report an unusual patient with a combination of two independently inherited genetic conditions; fibrinogen deficiency and early onset cortical atrophy. The study describes a male child from consanguineous family presented with hypofibrinogenemia, diffuse cortical atrophy, microcephaly, hypertonia and axonal motor neuropathy. Through a combination of homozygosity mapping and exome sequencing, we identified bi-allelic pathogenic mutations in two genes: a homozygous novel truncating mutation in FGG (c.554del; p.Lys185Argfs*14) and a homozygous missense mutation in TBCD (c.1423G > A;p.Ala475Thr). Loss of function mutations in FGG have been associated with fibrinogen deficiency, while the c.1423G > A mutation in TBCD causes a novel syndrome of neurodegeneration and early onset encephalopathy. Our study highlights the importance of homozygosity mapping and exome sequencing in molecular prenatal diagnosis, especially when multiple gene mutations are responsible for the phenotype.

Prenatal diagnosis of homozygous β-thalassemia

International Nuclear Information System (INIS)

Loukopoulos, D.

1980-11-01

An in vitro test for the prenatal diagnosis of homozygous β-thalassaemia and its application is described. The basic methodology consists in obtaining a minute specimen of placental blood by blind aspiration or foetoscopy at the 18th to 20th week of gestation, incubating a sample in the presence of 3 H-leucine, separating the labelled globin chains by chromatography on sodium carboxymethyl cellulose microcolumns with 8M urea-mercaptoethanol and measuring the radioactivity associated with the β- and γ-chains. The β/(pre-γ+γ) radioactivity ratio is used as an index of adequacy of β-chain synthesis, a value greater than 0.07 being taken as indicative of freedom from disease and a value less than 0.03 indicative of homozygous β-thalassaemia. From 350 women seeking the test, 344 samples were tested; 269 were judged normal or heterozygous, 75 homozygous for β-thalassaemia. Four false negatives were identified, 3 having given borderline β/(pre-γ+γ) ratios. Complications leading to foetal loss fell from 16% over the first year's experience to 8% over the second and 5% over the third. The test is now judged suitable for general use and is indeed being so used

Identification of MPL R102P Mutation in Hereditary Thrombocytosis.

Science.gov (United States)

Bellanné-Chantelot, Christine; Mosca, Matthieu; Marty, Caroline; Favier, Rémi; Vainchenker, William; Plo, Isabelle

2017-01-01

The molecular basis of hereditary thrombocytosis is germline mutations affecting the thrombopoietin (TPO)/TPO receptor (MPL)/JAK2 signaling axis. Here, we report one family presenting two cases with a mild thrombocytosis. By sequencing JAK2 and MPL coding exons, we identified a germline MPL R102P heterozygous mutation in the proband and his daughter. Concomitantly, we detected high TPO levels in the serum of these two patients. The mutation was not found in three other unaffected cases from the family except in another proband's daughter who did not present thrombocytosis but had a high TPO level. The MPL R102P mutation was first described in congenital amegakaryocytic thrombocytopenia in a homozygous state with a loss-of-function activity. It was previously shown that MPL R102P was blocked in the endoplasmic reticulum without being able to translocate to the plasma membrane. Thus, this case report identifies for the first time that MPL R102P mutation can differently impact megakaryopoiesis: thrombocytosis or thrombocytopenia depending on the presence of the heterozygous or homozygous state, respectively. The paradoxical effect associated with heterozygous MPL R102P may be due to subnormal cell-surface expression of wild-type MPL in platelets inducing a defective TPO clearance. As a consequence, increased TPO levels may activate megakaryocyte progenitors that express a lower, but still sufficient level of MPL for the induction of proliferation.

Identification of MPL R102P Mutation in Hereditary Thrombocytosis

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Christine Bellanné-Chantelot

2017-09-01

Full Text Available The molecular basis of hereditary thrombocytosis is germline mutations affecting the thrombopoietin (TPO/TPO receptor (MPL/JAK2 signaling axis. Here, we report one family presenting two cases with a mild thrombocytosis. By sequencing JAK2 and MPL coding exons, we identified a germline MPL R102P heterozygous mutation in the proband and his daughter. Concomitantly, we detected high TPO levels in the serum of these two patients. The mutation was not found in three other unaffected cases from the family except in another proband’s daughter who did not present thrombocytosis but had a high TPO level. The MPL R102P mutation was first described in congenital amegakaryocytic thrombocytopenia in a homozygous state with a loss-of-function activity. It was previously shown that MPL R102P was blocked in the endoplasmic reticulum without being able to translocate to the plasma membrane. Thus, this case report identifies for the first time that MPL R102P mutation can differently impact megakaryopoiesis: thrombocytosis or thrombocytopenia depending on the presence of the heterozygous or homozygous state, respectively. The paradoxical effect associated with heterozygous MPL R102P may be due to subnormal cell-surface expression of wild-type MPL in platelets inducing a defective TPO clearance. As a consequence, increased TPO levels may activate megakaryocyte progenitors that express a lower, but still sufficient level of MPL for the induction of proliferation.

Association of HFE gene C282Y and H63D mutations with liver cirrhosis in the Lithuanian population

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Simonas Juzėnas

2016-01-01

Conclusions: Heterozygous C282Y mutation of the HFE gene was associated with liver cirrhosis in the Lithuanian population. In gender-related analysis, heterozygous C282Y and homozygous H63D mutations were linked to liver cirrhosis in men, not in women.

Filaggrin compound heterozygous patients carry mutations in trans position

DEFF Research Database (Denmark)

Carlsen, Berit C; Meldgaard, Michael; Johansen, Jeanne D

2013-01-01

by means of allele-specific PCR amplification and analysis of PCR products by agarose gel electrophoresis. All R501X/2282del4 compound heterozygous samples collected over a 4-year period of routine FLG mutation testing were investigated. In total, 37 samples were tested. All thirty-seven R501X/2282del4......More than 40 null mutations in the filaggrin (FLG) gene are described. It is therefore possible to find two different null mutations in one individual (compound heterozygosity). It has been generally perceived that homozygous and compound heterozygous individuals were genotypically comparable......; however, this has not been scientifically investigated. Two different FLG null mutations in the same individual may be in trans position, meaning that each mutation locates to a different allele functionally equivalent to homozygosity, or may be in cis position, meaning that both mutations locate...

DNA Fragmentation Factor 45 (DFF45 Gene at 1p36.2 Is Homozygously Deleted and Encodes Variant Transcripts in Neuroblastoma Cell Line

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Hong Wei Yang

2001-01-01

Full Text Available Recently, loss of heterozygosity (LOH studies suggest that more than two tumor suppressor genes lie on the short arm of chromosome 1 (1p in neuroblastoma (NB. To identify candidate tumor suppressor genes in NB, we searched for homozygous deletions in 20 NB cell lines using a high-density STS map spanning chromosome 1 p36, a common LOH region in NB. We found that the 45-kDa subunit of the DNA fragmentation factor (DFF45 gene was homozygously deleted in an NB cell line, NB-1. DFF45 is the chaperon of DFF40, and both molecules are necessary for caspase 3 to induce apoptosis. DFF35, a splicing variant of DFF45, is an inhibitor of DFF40. We examined 20 NB cell lines for expression and mutation of DFF45 gene by reverse transcription (RT-polymerase chain reaction (PCR and RT-PCR-single-strand conformation polymorphism. Some novel variant transcripts of the DFF45 gene were found in NB cell lines, but not in normal adrenal gland and peripheral blood. These variants may not serve as chaperons of DFF40, but as inhibitors like DFF35, thus disrupting the balance between DFF45 and DFF40. No mutations of the DFF45 gene were found in any NB cell line, suggesting that the DFF45 is not a tumor suppressor gene for NB. However, homozygous deletion of the DFF45 gene in the NB-1 cell line may imply the presence of unknown tumor suppressor genes in this region.

Mutations in a novel gene with transmembrane domains underlie Usher syndrome type 3.

Science.gov (United States)

Joensuu, T; Hämäläinen, R; Yuan, B; Johnson, C; Tegelberg, S; Gasparini, P; Zelante, L; Pirvola, U; Pakarinen, L; Lehesjoki, A E; de la Chapelle, A; Sankila, E M

2001-10-01

Usher syndrome type 3 (USH3) is an autosomal recessive disorder characterized by progressive hearing loss, severe retinal degeneration, and variably present vestibular dysfunction, assigned to 3q21-q25. Here, we report on the positional cloning of the USH3 gene. By haplotype and linkage-disequilibrium analyses in Finnish carriers of a putative founder mutation, the critical region was narrowed to 250 kb, of which we sequenced, assembled, and annotated 207 kb. Two novel genes-NOPAR and UCRP-and one previously identified gene-H963-were excluded as USH3, on the basis of mutational analysis. USH3, the candidate gene that we identified, encodes a 120-amino-acid protein. Fifty-two Finnish patients were homozygous for a termination mutation, Y100X; patients in two Finnish families were compound heterozygous for Y100X and for a missense mutation, M44K, whereas patients in an Italian family were homozygous for a 3-bp deletion leading to an amino acid deletion and substitution. USH3 has two predicted transmembrane domains, and it shows no homology to known genes. As revealed by northern blotting and reverse-transcriptase PCR, it is expressed in many tissues, including the retina.

Mutations in the gene for lipoprotein lipase. A cause for low HDL cholesterol levels in individuals heterozygous for familial hypercholesterolemia

NARCIS (Netherlands)

Pimstone, S. N.; Gagné, S. E.; Gagné, C.; Lupien, P. J.; Gaudet, D.; Williams, R. R.; Kotze, M.; Reymer, P. W.; Defesche, J. C.; Kastelein, J. J.

1995-01-01

Familial hypercholesterolemia (FH) is characterized by elevated plasma concentrations of LDL cholesterol resulting from mutations in the gene for the LDL receptor. Low HDL cholesterol levels are seen frequently in patients both heterozygous and homozygous for mutations in this gene. Suggested

AURKA F31I Polymorphism and Breast Cancer Risk in BRCA1 and BRCA2 Mutation Carriers: A CIMBA study

Science.gov (United States)

Couch, Fergus J.; Sinilnikova, Olga; Vierkant, Robert A; Pankratz, V. Shane; Fredericksen, Zachary S.; Stoppa-Lyonnet, Dominique; Coupier, Isabelle; Hughes, David; Hardouin, Agnès; Berthet, Pascaline; Peock, Susan; Cook, Margaret; Baynes, Caroline; Hodgson, Shirley; Morrison, Patrick J.; Porteous, Mary E.; Jakubowska, Anna; Lubinski, Jan; Gronwald, Jacek; Spurdle, Amanda B.; Schmutzler, Rita; Versmold, Beatrix; Engel, Christoph; Meindl, Alfons; Sutter, Christian; Horst, Jurgen; Schaefer, Dieter; Offit, Kenneth; Kirchhoff, Tomas; Andrulis, Irene L.; Ilyushik, Eduard; Glendon, Gordon; Devilee, Peter; Vreeswijk, Maaike P.G.; Vasen, Hans F.A.; Borg, Ake; Backenhorn, Katja; Struewing, Jeffery P.; Greene, Mark H.; Neuhausen, Susan L.; Rebbeck, Timothy R.; Nathanson, Katherine; Domchek, Susan; Wagner, Theresa; Garber, Judy E.; Szabo, Csilla; Zikan, Michal; Foretova, Lenka; Olson, Janet E.; Sellers, Thomas A.; Lindor, Noralane; Nevanlinna, Heli; Tommiska, Johanna; Aittomaki, Kristiina; Hamann, Ute; Rashid, Muhammad U.; Torres, Diana; Simard, Jacques; Durocher, Francine; Guenard, Frederic; Lynch, Henry T.; Isaacs, Claudine; Weitzel, Jeffrey; Olopade, Olufunmilayo I.; Narod, Steven; Daly, Mary B.; Godwin, Andrew K.; Tomlinson, Gail; Easton, Douglas F.; Chenevix-Trench, Georgia; Antoniouon, Antonis C.

2009-01-01

The AURKA oncogene is associated with abnormal chromosome segregation and aneuploidy and predisposition to cancer. Amplification of AURKA has been detected at higher frequency in tumors from BRCA1 and BRCA2 mutation carriers than in sporadic breast tumors, suggesting that overexpression of AURKA and inactivation of BRCA1 and BRCA2 co-operate during tumor development and progression. The F31I polymorphism in AURKA has been associated with breast cancer risk in the homozygous state in prior studies. We evaluated whether the AURKA F31I polymorphism modifies breast cancer risk in BRCA1 and BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). CIMBA was established to provide sufficient statistical power through increased numbers of mutation carriers to identify polymorphisms that act as modifiers of cancer risk and can refine breast cancer risk estimates in BRCA1 and BRCA2 mutation carriers. A total of 4935 BRCA1 and 2241 BRCA2 mutation carriers and 11 individuals carrying both BRCA1 and BRCA2 mutations were genotyped for F31I. Overall, homozygosity for the 31I allele was not significantly associated with breast cancer risk in BRCA1 and BRCA2 carriers combined (HR = 0.91; 95% CI 0.77-1.06). Similarly, no significant association was seen in BRCA1 (HR = 0.90; 95% CI 0.75-1.08) or BRCA2 carriers (HR = 0.93; 95% CI 0.67-1.29) or when assessing the modifying effects of either bilateral prophylactic oophorectomy or menopausal status of BRCA1 and BRCA2 carriers. In summary, the F31I polymorphism in AURKA is not associated with a modified risk of breast cancer in BRCA1 and BRCA2 carriers. PMID:17627006

Identification of a pathogenic FTO mutation by next-generation sequencing in a newborn with growth retardation and developmental delay.

Science.gov (United States)

Daoud, Hussein; Zhang, Dong; McMurray, Fiona; Yu, Andrea; Luco, Stephanie M; Vanstone, Jason; Jarinova, Olga; Carson, Nancy; Wickens, James; Shishodia, Shifali; Choi, Hwanho; McDonough, Michael A; Schofield, Christopher J; Harper, Mary-Ellen; Dyment, David A; Armour, Christine M

2016-03-01

A homozygous loss-of-function mutation p.(Arg316Gln) in the fat mass and obesity-associated (FTO) gene, which encodes for an iron and 2-oxoglutarate-dependent oxygenase, was previously identified in a large family in which nine affected individuals present with a lethal syndrome characterised by growth retardation and multiple malformations. To date, no other pathogenic mutation in FTO has been identified as a cause of multiple congenital malformations. We investigated a 21-month-old girl who presented distinctive facial features, failure to thrive, global developmental delay, left ventricular cardiac hypertrophy, reduced vision and bilateral hearing loss. We performed targeted next-generation sequencing of 4813 clinically relevant genes in the patient and her parents. We identified a novel FTO homozygous missense mutation (c.956C>T; p.(Ser319Phe)) in the affected individual. This mutation affects a highly conserved residue located in the same functional domain as the previously characterised mutation p.(Arg316Gln). Biochemical studies reveal that p.(Ser319Phe) FTO has reduced 2-oxoglutarate turnover and N-methyl-nucleoside demethylase activity. Our findings are consistent with previous reports that homozygous mutations in FTO can lead to rare growth retardation and developmental delay syndrome, and further support the proposal that FTO plays an important role in early development of human central nervous and cardiovascular systems. 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/

Chloroplast mutations induced by 9-aminoacridine hydrochloride are independent of the plastome mutator in Oenothera.

Science.gov (United States)

GuhaMajumdar, M; Baldwin, S; Sears, B B

2004-02-01

Oenothera plants homozygous for the recessive plastome mutator allele ( pm) show chloroplast DNA (cpDNA) mutation frequencies that are about 1,000-fold higher than spontaneous levels. The pm-encoded gene product has been hypothesized to have a function in cpDNA replication, repair and/or mutation avoidance. Previous chemical mutagenesis experiments with the alkylating agent nitroso-methyl urea (NMU) showed a synergistic effect of NMU on the induction of mutations in the pm line, suggesting an interaction between the pm-encoded gene product and one of the repair systems that corrects alkylation damage. The goal of the experiments described here was to examine whether the pm activity extends to the repair of damage caused by non-alkylating mutagens. To this end, the intercalating mutagen, 9-aminoacridine hydrochloride (9AA) was tested for synergism with the plastome mutator. A statistical analysis of the data reported here indicates that the pm-encoded gene product is not involved in the repair of the 9AA-induced mutations. However, the recovery of chlorotic sectors in plants derived from the mutagenized seeds shows that 9AA can act as a mutagen of the chloroplast genome.

Fetal loss in homozygous mutant Norrie disease mice: a new role of Norrin in reproduction.

Science.gov (United States)

Luhmann, Ulrich F O; Meunier, Dominique; Shi, Wei; Lüttges, Angela; Pfarrer, Christiane; Fundele, Reinald; Berger, Wolfgang

2005-08-01

Mutations in the Norrie disease pseudoglioma gene (NDP) are known to cause X-linked recessive Norrie disease. In addition, NDP mutations have been found in other vasoproliferative retinopathies such as familial exudative vitreoretinopathy, retinopathy of prematurity, and Coats disease, suggesting a role for Norrin in vascular development. Here we report that female mice homozygous for the Norrie disease pseudoglioma homolog (Ndph) knockout allele exhibit almost complete infertility, while heterozygous females and hemizygous males are fertile. Histological examinations and RNA in situ hybridization analyses revealed defects in vascular development and decidualization in pregnant Ndph-/- females from embryonic day 7 (E7) onwards, resulting in embryonic loss. Using RT-PCR analyses we also demonstrate, for the first time, the expression of Ndph in mouse uteri and deciduae as well as the expression of NDP in human placenta. Taken together, these data provide strong evidence for Norrin playing an important role in female reproductive tissues. Copyright 2005 Wiley-Liss, Inc

Somatic mutations of the histone H3K27 demethylase, UTX, in human cancer

Science.gov (United States)

van Haaften, Gijs; Dalgliesh, Gillian L; Davies, Helen; Chen, Lina; Bignell, Graham; Greenman, Chris; Edkins, Sarah; Hardy, Claire; O’Meara, Sarah; Teague, Jon; Butler, Adam; Hinton, Jonathan; Latimer, Calli; Andrews, Jenny; Barthorpe, Syd; Beare, Dave; Buck, Gemma; Campbell, Peter J; Cole, Jennifer; Dunmore, Rebecca; Forbes, Simon; Jia, Mingming; Jones, David; Kok, Chai Yin; Leroy, Catherine; Lin, Meng-Lay; McBride, David J; Maddison, Mark; Maquire, Simon; McLay, Kirsten; Menzies, Andrew; Mironenko, Tatiana; Lee, Mulderrig; Mudie, Laura; Pleasance, Erin; Shepherd, Rebecca; Smith, Raffaella; Stebbings, Lucy; Stephens, Philip; Tang, Gurpreet; Tarpey, Patrick S; Turner, Rachel; Turrell, Kelly; Varian, Jennifer; West, Sofie; Widaa, Sara; Wray, Paul; Collins, V Peter; Ichimura, Koichi; Law, Simon; Wong, John; Yuen, Siu Tsan; Leung, Suet Yi; Tonon, Giovanni; DePinho, Ronald A; Tai, Yu-Tzu; Anderson, Kenneth C; Kahnoski, Richard J.; Massie, Aaron; Khoo, Sok Kean; Teh, Bin Tean; Stratton, Michael R; Futreal, P Andrew

2010-01-01

Somatically acquired epigenetic changes are present in many cancers. Epigenetic regulation is maintained via post-translational modifications of core histones. Here, we describe inactivating somatic mutations in the histone lysine demethylase, UTX, pointing to histone H3 lysine methylation deregulation in multiple tumour types. UTX reintroduction into cancer cells with inactivating UTX mutations resulted in slowing of proliferation and marked transcriptional changes. These data identify UTX as a new human cancer gene. PMID:19330029

Tsc2 gene inactivation causes a more severe epilepsy phenotype than Tsc1 inactivation in a mouse model of tuberous sclerosis complex.

Science.gov (United States)

Zeng, Ling-Hui; Rensing, Nicholas R; Zhang, Bo; Gutmann, David H; Gambello, Michael J; Wong, Michael

2011-02-01

Tuberous Sclerosis Complex (TSC) is an autosomal dominant, multi-system disorder, typically involving severe neurological symptoms, such as epilepsy, cognitive deficits and autism. Two genes, TSC1 and TSC2, encoding the proteins hamartin and tuberin, respectively, have been identified as causing TSC. Although there is a substantial overlap in the clinical phenotype produced by TSC1 and TSC2 mutations, accumulating evidence indicates that TSC2 mutations cause more severe neurological manifestations than TSC1 mutations. In this study, the neurological phenotype of a novel mouse model involving conditional inactivation of the Tsc2 gene in glial-fibrillary acidic protein (GFAP)-positive cells (Tsc2(GFAP1)CKO mice) was characterized and compared with previously generated Tsc1(GFAP1)CKO mice. Similar to Tsc1(GFAP1)CKO mice, Tsc2(GFAP1)CKO mice exhibited epilepsy, premature death, progressive megencephaly, diffuse glial proliferation, dispersion of hippocampal pyramidal cells and decreased astrocyte glutamate transporter expression. However, Tsc2(GFAP1)CKO mice had an earlier onset and higher frequency of seizures, as well as significantly more severe histological abnormalities, compared with Tsc1(GFAP1)CKO mice. The differences between Tsc1(GFAP1)CKO and Tsc2(GFAP1)CKO mice were correlated with higher levels of mammalian target of rapamycin (mTOR) activation in Tsc2(GFAP1)CKO mice and were reversed by the mTOR inhibitor, rapamycin. These findings provide novel evidence in mouse models that Tsc2 mutations intrinsically cause a more severe neurological phenotype than Tsc1 mutations and suggest that the difference in phenotype may be related to the degree to which Tsc1 and Tsc2 inactivation causes abnormal mTOR activation.

A Novel Mutation in the Transglutaminase-1 Gene in an Autosomal Recessive Congenital Ichthyosis Patient

Directory of Open Access Journals (Sweden)

D. Vaigundan

2014-01-01

Full Text Available Structure-function implication on a novel homozygous Trp250/Gly mutation of transglutaminase-1 (TGM1 observed in a patient of autosomal recessive congenital ichthyosis is invoked from a bioinformatics analysis. Structural consequences of this mutation are hypothesized in comparison to homologous enzyme human factor XIIIA accepted as valid in similar structural analysis and are projected as guidelines for future studies at an experimental level on TGM1 thus mutated.

The Charles River "hairless" rat mutation is distinct from the hairless mouse alleles.

Science.gov (United States)

Panteleyev, A A; Christiano, A M

2001-02-01

The Charles River (CR) "hairless" rat is one of the autosomal recessive hypotrichotic animal models actively studied in pharmacologic and dermatologic research. Despite its widespread use, the molecular basis of this monogenic mutation remains unknown, and the skin histologic features of this phenotype have never been described. However, the designation "hairless" has been used as an extension of the hairless mouse (hr) nomenclature on the basis of the clinical absence of hairs in both phenotypes. We present a description of the histopathologic changes in heterozygous and homozygous CR hairless rat mutants during the first month of life. The postnatal homozygous rat skin was characterized by abnormal keratinization of the hair shaft and formation of a thick and dense layer of corneocytes in the lower portion of the epidermal stratum corneum. This layer prevented the improperly keratinized hair shaft from penetrating the skin surface. Starting from the latest stages of hair follicle (HF) development, obvious signs of HF degeneration were observed in homozygous skin. This process was extremely rapid, and by day 12, mainly atrophic HFs with abnormal or broken hairs were present in the skin. Therefore, the mutation in the CR rat abrogates cell proliferation in the hair matrix and affects keratinocyte differentiation in the HF and interfollicular epidermis, a phenotype that is completely distinct from hr/hr. To test whether the CR rat harbored a mutation in the hr gene, we analyzed the coding region of this gene and consensus intron splice site sequences in mutant rats and found no mutation, further supporting phenotypic evidence that the hairless phenotype in CR rats is not allelic with hairless. Finally, using intragenic polymorphisms, we were able to exclude homozygosity at the hairless locus by use of genotypic analysis. Thus, morphologic analysis of successive stages of phenotype development in the CR hairless rat, together with definitive molecular studies

Exclusion of homozygous PLCE1 (NPHS3) mutations in 69 families with idiopathic and hereditary FSGS.

LENUS (Irish Health Repository)

Gbadegesin, Rasheed

2009-02-01

Focal and segmental glomerulosclerosis (FSGS) is the most common glomerular cause of end-stage kidney disease (ESKD). Although the etiology of FSGS has not been fully elucidated, recent results from the positional cloning of genes mutated in nephrotic syndromes are now beginning to provide insight into the pathogenesis of these diseases. Mutations in PLCE1\\/NPHS3 have recently been reported as a cause of nephrotic syndrome characterized by diffuse mesangial sclerosis (DMS) histology. One single family with a missense mutation had late onset of the disease that was characterized by FSGS. To further define the role of PLCE1 mutations in the etiology of FSGS, we performed mutational analysis in 69 families with FSGS. A total of 69 families with 231 affected individuals were examined. The median age of disease onset was 26 years (range 1-66 years). Onset of ESKD was at a median age of 35.5 years. Seven variants leading to non-synonymous changes were found, of which only two are new variants (exon 4 c.1682 G>A R561Q, exon 31 c.6518A>G K2173R). No known disease-causing mutations were identified in the families screened. PLCE1\\/NPHS3 mutations are not a cause of FSGS in this cohort. The absence of mutations in PLCE1\\/NPHS3 in this study indicates that there are additional genetic causes of FSGS and that hereditary FSGS is a heterogeneous disease. Kindreds appropriate for genome-wide screening are currently being subjected to analysis with the aim of identifying other genetic causes of FSGS.

A Novel FOXE1 Mutation (R73S) in Bamforth–Lazarus Syndrome Causing Increased Thyroidal Gene Expression

Science.gov (United States)

Carré, Aurore; Hamza, Rasha T.; Kariyawasam, Dulanjalee; Guillot, Loïc; Teissier, Raphaël; Tron, Elodie; Castanet, Mireille; Dupuy, Corinne; El Kholy, Mohamed; Polak, Michel

2014-01-01

Background: Homozygous loss-of-function mutations in the FOXE1 gene have been reported in several patients with partial or complete Bamforth–Lazarus syndrome: congenital hypothyroidism (CH) with thyroid dysgenesis (usually athyreosis), cleft palate, spiky hair, with or without choanal atresia, and bifid epiglottis. Here, our objective was to evaluate potential functional consequences of a FOXE1 mutation in a patient with a similar clinical phenotype. Methods: FOXE1 was sequenced in eight patients with thyroid dysgenesis and cleft palate. Transient transfection was performed in HEK293 cells using the thyroglobulin (TG) and thyroid peroxidase (TPO) promoters in luciferase reporter plasmids to assess the functional impact of the FOXE1 mutations. Primary human thyrocytes transfected with wild type and mutant FOXE1 served to assess the impact of the mutation on endogenous TG and TPO expression. Results: We identified and characterized the function of a new homozygous FOXE1 missense mutation (p.R73S) in a boy with a typical phenotype (athyreosis, cleft palate, and partial choanal atresia). This new mutation located within the forkhead domain was inherited from the heterozygous healthy consanguineous parents. In vitro functional studies in HEK293 cells showed that this mutant gene enhanced the activity of the TG and TPO gene promoters (1.5-fold and 1.7-fold respectively vs. wild type FOXE1; p<0.05), unlike the five mutations previously reported in Bamforth–Lazarus syndrome. The gain-of-function effect of the FOXE1-p.R73S mutant gene was confirmed by an increase in endogenous TG production in primary human thyrocytes. Conclusion: We identified a new homozygous FOXE1 mutation responsible for enhanced expression of the TG and TPO genes in a boy whose phenotype is similar to that reported previously in patients with loss-of-function FOXE1 mutations. This finding further delineates the role for FOXE1 in both thyroid and palate development, and shows that enhanced gene

A novel D458V mutation in the SANS PDZ binding motif causes atypical Usher syndrome.

Science.gov (United States)

Kalay, E; de Brouwer, A P M; Caylan, R; Nabuurs, S B; Wollnik, B; Karaguzel, A; Heister, J G A M; Erdol, H; Cremers, F P M; Cremers, C W R J; Brunner, H G; Kremer, H

2005-12-01

Homozygosity mapping and linkage analysis in a Turkish family with autosomal recessive prelingual sensorineural hearing loss revealed a 15-cM critical region at 17q25.1-25.3 flanked by the polymorphic markers D17S1807 and D17S1806. The maximum two-point lod score was 4.07 at theta=0.0 for the marker D17S801. The linkage interval contains the Usher syndrome 1G gene (USH1G) that is mutated in patients with Usher syndrome (USH) type 1g and encodes the SANS protein. Mutation analysis of USH1G led to the identification of a homozygous missense mutation D458V at the -3 position of the PDZ binding motif of SANS. This mutation was also present homozygously in one out of 64 additional families from Turkey with autosomal recessive nonsyndromic hearing loss and heterozygously in one out of 498 control chromosomes. By molecular modeling, we provide evidence that this mutation impairs the interaction of SANS with harmonin. Ophthalmologic examination and vestibular evaluation of patients from both families revealed mild retinitis pigmentosa and normal vestibular function. These results suggest that these patients suffer from atypical USH.

Induction of mutation in Micrococcus pyogenes by chemical inactivation of sulfhydryl groups

Energy Technology Data Exchange (ETDEWEB)

Clark, J B; Wyss, O; Stone, W S

1950-08-26

The purpose of this work was to determine whether this naphthaquinone could induce antibiotic-resistant mutants in Micrococcus pyogenes var. aureus, and to determine if such mutagenicity was due to -SH inactivation.

recA+-dependent inactivation of the lambda repressor in Escherichia coli lysogens by γ-radiation and by tif expression

International Nuclear Information System (INIS)

West, S.C.; Powell, K.A.; Emmerson, P.T.

1975-01-01

When lambda lysogens of E. coli are induced by γ-radiation the lambda repressor, as measured by its specific binding to lambda DNA, is rapidly inactivated by a recA + -dependent process which does not require new protein synthesis. This rapid inactivation is similar to inactivation of repressor by expression of the temperature sensitive E. coli mutation tif. In contrast, induction by UV irradiation or mitomycin C treatment requires new protein synthesis and there is a lag before the repressor is inactivated (Tomizawa and Ogawa, 1967; Shinagawa and Itoh, 1973). (orig.) [de

Effect of Hereditary Hemochromatosis Gene H63D and C282Y Mutations on Iron Overload in Sickle Cell Disease Patients

Directory of Open Access Journals (Sweden)

Yunus Kasım Terzi

2016-12-01

Full Text Available Objective: Hemochromatosis is an autosomal recessive disease that is one of the most important reasons for iron overload. Sickle cell disease is a hemoglobinopathy that occurs as a result of a homozygous mutation in the hemoglobin gene. Erythrocyte transfusion is frequently used in the treatment of this disease. Iron overload as a result of transfusion is important in the mortality and morbidity of sickle cell anemia patients as well as in other hemoglobinopathies. In this study, the effect of hemochromatosis gene (HFE p.H63D and p.C282Y mutations on transfusion-related cardiac and liver iron overload in sickle cell disease patients who carry homozygous hemoglobin S mutation has been investigated. Materials and Methods: This is a prospective single-center crosssectional study in patients with homozygous hemoglobin S mutation between the years 2008 and 2013. The patients were divided into two groups. The first group (group A, n=31 was receiving chelation therapy and the second group (group B, n=13 was not. Direct and indirect iron loads were analyzed by magnetic resonance imaging and biochemically, respectively. HFE gene mutations were analyzed by polymerase chain reaction-restriction fragment length polymorphism method. Statistical analyses were performed by independent samples t-test. Results: p.H63D mutation was detected in 10 (32.3% patients in group A and in only 1 patient (7.7% in group B. When the 2 groups were compared for iron overload, iron deposition in the liver was significantly higher in group B (p=0.046. In addition, in group A, iron deposition was significantly higher in HFE mutation carriers compared to patients without the mutation (p=0.05. Conclusion: Results of this study showed that HFE gene mutations are important in iron deposition in the liver in patients with sickle cell disease.

A novel homozygous truncating GNAT1 mutation implicated in retinal degeneration

OpenAIRE

Carrigan, Matthew; Duignan, Emma; Humphries, Pete; Palfi, Arpad; Kenna, Paul F; Farrar, G Jane

2015-01-01

Background The GNAT1 gene encodes the ? subunit of the rod transducin protein, a key element in the rod phototransduction cascade. Variants in GNAT1 have been implicated in stationary night-blindness in the past, but unlike other proteins in the same pathway, it has not previously been implicated in retinitis pigmentosa. Methods A panel of 182 retinopathy-associated genes was sequenced to locate disease-causing mutations in patients with inherited retinopathies. Results Sequencing revealed a ...

Increased yield of heterologous viral glycoprotein in the seeds of homozygous transgenic tobacco plants cultivated underground.

Science.gov (United States)

Tackaberry, Eilleen S; Prior, Fiona; Bell, Margaret; Tocchi, Monika; Porter, Suzanne; Mehic, Jelica; Ganz, Peter R; Sardana, Ravinder; Altosaar, Illimar; Dudani, Anil

2003-06-01

The use of transgenic plants in the production of recombinant proteins for human therapy, including subunit vaccines, is being investigated to evaluate the efficacy and safety of these emerging biopharmaceutical products. We have previously shown that synthesis of recombinant glycoprotein B (gB) of human cytomegalovirus can be targeted to seeds of transgenic tobacco when directed by the rice glutelin 3 promoter, with gB retaining critical features of immunological reactivity (E.S. Tackaberry et al. 1999. Vaccine, 17: 3020-3029). Here, we report development of second generation transgenic plant lines (T1) homozygous for the transgene. Twenty progeny plants from two lines (A23T(1)-2 and A24T(1)-3) were grown underground in an environmentally contained mine shaft. Based on yields of gB in their seeds, the A23T(1)-2 line was then selected for scale-up in the same facility. Analyses of mature seeds by ELISA showedthat gB specific activity in A23T(1)-2 seeds was over 30-fold greater than the best T0 plants from the same transformation series, representing 1.07% total seed protein. These data demonstrate stable inheritance, an absence of transgene inactivation, and enhanced levels of gB expression in a homozygous second generation plant line. They also provide evidence for the suitability of using this environmentally secure facility to grow transgenic plants producing therapeutic biopharmaceuticals.

Digenic mutations involving both the BSND and GJB2 genes detected in Bartter syndrome type IV.

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Wang, Hong-Han; Feng, Yong; Li, Hai-Bo; Wu, Hong; Mei, Ling-Yun; Wang, Xing-Wei; Jiang, Lu; He, Chu-Feng

2017-01-01

Bartter syndrome type IV, characterized by salt-losing nephropathies and sensorineural deafness, is caused by mutations of BSND or simultaneous mutations of both CLCNKA and CLCNKB. GJB2 is the primary causative gene for non-syndromic sensorineural deafness and associated with several syndromic sensorineural deafness. Owing to the rarity of Bartter syndrome, only a few mutations have been reported in the abovementioned causative genes. To investigate the underlying mutations in a Chinese patient with Bartter syndrome type IV, genetic analysis of BSND, CLCNKA, CLCNKB and GJB2 were performed by polymerase chain reaction and direct sequencing. Finally, double homozygous mutations c.22C > T (p.Arg8Trp) and c.127G > A (Val43Ile) were detected in exon 1 of BSND. Intriguingly, compound heterozygous mutations c.235delC (p.Leu79CysfsX3) and c.109G > A (p.Val37Ile) were also revealed in exon 2 of GJB2 in the same patient. No pathogenic mutations were found in CLCNKA and CLCNKB. Our results indicated that the homozygous mutation c.22C > T was the key genetic reason for the proband, and a digenic effect of BSND and GJB2 might contributed to sensorineural deafness. To our knowledge, it was the first report showing that the GJB2 gene mutations were detected in Bartter syndrome. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Electroclinical presentation and genotype-phenotype relationships in patients with Unverricht-Lundborg disease carrying compound heterozygous CSTB point and indel mutations.

Science.gov (United States)

Canafoglia, Laura; Gennaro, Elena; Capovilla, Giuseppe; Gobbi, Giuseppe; Boni, Antonella; Beccaria, Francesca; Viri, Maurizio; Michelucci, Roberto; Agazzi, Pamela; Assereto, Stefania; Coviello, Domenico A; Di Stefano, Maria; Rossi Sebastiano, Davide; Franceschetti, Silvana; Zara, Federico

2012-12-01

Unverricht-Lundborg disease (EPM1A) is frequently due to an unstable expansion of a dodecamer repeat in the CSTB gene, whereas other types of mutations are rare. EPM1A due to homozygous expansion has a rather stereotyped presentation with prominent action myoclonus. We describe eight patients with five different compound heterozygous CSTB point or indel mutations in order to highlight their particular phenotypical presentations and evaluate their genotype-phenotype relationships. We screened CSTB mutations by means of Southern blotting and the sequencing of the genomic DNA of each proband. CSTB messenger RNA (mRNA) aberrations were characterized by sequencing the complementary DNA (cDNA) of lymphoblastoid cells, and assessing the protein concentrations in the lymphoblasts. The patient evaluations included the use of a simplified myoclonus severity rating scale, multiple neurophysiologic tests, and electroencephalography (EEG)-polygraphic recordings. To highlight the particular clinical features and disease time-course in compound heterozygous patients, we compared some of their characteristics with those observed in a series of 40 patients carrying the common homozygous expansion mutation observed at the C. Besta Foundation, Milan, Italy. The eight compound heterozygous patients belong to six EPM1A families (out of 52; 11.5%) diagnosed at the Laboratory of Genetics of the Galliera Hospitals in Genoa, Italy. They segregated five different heterozygous point or indel mutations in association with the common dodecamer expansion. Four patients from three families had previously reported CSTB mutations (c.67-1G>C and c.168+1_18del); one had a novel nonsense mutation at the first exon (c.133C>T) leading to a premature stop codon predicting a short peptide; the other three patients from two families had a complex novel indel mutation involving the donor splice site of intron 2 (c.168+2_169+21delinsAA) and leading to an aberrant transcript with a partially retained intron

HFE gene mutations and iron status of Brazilian blood donors.

Science.gov (United States)

Santos, P C J L; Cançado, R D; Terada, C T; Rostelato, S; Gonzales, I; Hirata, R D C; Hirata, M H; Chiattone, C S; Guerra-Shinohara, E M

2010-01-01

Mutations of the HFE and TFR2 genes have been associated with iron overload. HFE and TFR2 mutations were assessed in blood donors, and the relationship with iron status was evaluated. Subjects (N = 542) were recruited at the Hemocentro da Santa Casa de São Paulo, São Paulo, Brazil. Iron status was not influenced by HFE mutations in women and was independent of blood donation frequency. In contrast, men carrying the HFE 282CY genotype had lower total iron-binding capacity (TIBC) than HFE 282CC genotype carriers. Men who donated blood for the first time and were carriers of the HFE 282CY genotype had higher transferrin saturation values and lower TIBC concentrations than those with the homozygous wild genotype for the HFE C282Y mutation. Moreover, in this group of blood donors, carriers of HFE 63DD plus 63HD genotypes had higher serum ferritin values than those with the homozygous wild genotype for HFE H63D mutation. Multiple linear regression analysis showed that HFE 282CY leads to a 17.21% increase (P = 0.018) and a 83.65% decrease (P = 0.007) in transferrin saturation and TIBC, respectively. In addition, serum ferritin is influenced by age (3.91%, P = 0.001) and the HFE 63HD plus DD genotype (55.84%, P = 0.021). In conclusion, the HFE 282Y and 65C alleles were rare, while the HFE 63D allele was frequent in Brazilian blood donors. The HFE C282Y and H63D mutations were associated with alterations in iron status in blood donors in a gender-dependent manner.

HFE gene mutations and iron status of Brazilian blood donors

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P.C.J.L. Santos

2010-01-01

Full Text Available Mutations of the HFE and TFR2 genes have been associated with iron overload. HFE and TFR2 mutations were assessed in blood donors, and the relationship with iron status was evaluated. Subjects (N = 542 were recruited at the Hemocentro da Santa Casa de São Paulo, São Paulo, Brazil. Iron status was not influenced by HFE mutations in women and was independent of blood donation frequency. In contrast, men carrying the HFE 282CY genotype had lower total iron-binding capacity (TIBC than HFE 282CC genotype carriers. Men who donated blood for the first time and were carriers of the HFE 282CY genotype had higher transferrin saturation values and lower TIBC concentrations than those with the homozygous wild genotype for the HFE C282Y mutation. Moreover, in this group of blood donors, carriers of HFE 63DD plus 63HD genotypes had higher serum ferritin values than those with the homozygous wild genotype for HFE H63D mutation. Multiple linear regression analysis showed that HFE 282CY leads to a 17.21% increase (P = 0.018 and a 83.65% decrease (P = 0.007 in transferrin saturation and TIBC, respectively. In addition, serum ferritin is influenced by age (3.91%, P = 0.001 and the HFE 63HD plus DD genotype (55.84%, P = 0.021. In conclusion, the HFE 282Y and 65C alleles were rare, while the HFE 63D allele was frequent in Brazilian blood donors. The HFE C282Y and H63D mutations were associated with alterations in iron status in blood donors in a gender-dependent manner.

Identification of a c.544C>T mutation in WDR34 as a deleterious recessive allele of short rib-polydactyly syndrome

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Shu-Han You

2017-12-01

Conclusion: This study was the first to identify c.544C > T [p.Arg182Trp] mutation in WDR34 in a patient with SRPS. According to the database, the homozygous mutation of c.544C > T in WDR34 was deleterious and the prevalence of heterozygous mutation was relatively higher in Asian population. More studies of this mutation in patients with SRPS are required.

Mutations in Alström protein impair terminal differentiation of cardiomyocytes.

Science.gov (United States)

Shenje, Lincoln T; Andersen, Peter; Halushka, Marc K; Lui, Cecillia; Fernandez, Laviel; Collin, Gayle B; Amat-Alarcon, Nuria; Meschino, Wendy; Cutz, Ernest; Chang, Kenneth; Yonescu, Raluca; Batista, Denise A S; Chen, Yan; Chelko, Stephen; Crosson, Jane E; Scheel, Janet; Vricella, Luca; Craig, Brian D; Marosy, Beth A; Mohr, David W; Hetrick, Kurt N; Romm, Jane M; Scott, Alan F; Valle, David; Naggert, Jürgen K; Kwon, Chulan; Doheny, Kimberly F; Judge, Daniel P

2014-03-04

Cardiomyocyte cell division and replication in mammals proceed through embryonic development and abruptly decline soon after birth. The process governing cardiomyocyte cell cycle arrest is poorly understood. Here we carry out whole-exome sequencing in an infant with evidence of persistent postnatal cardiomyocyte replication to determine the genetic risk factors. We identify compound heterozygous ALMS1 mutations in the proband, and confirm their presence in her affected sibling, one copy inherited from each heterozygous parent. Next, we recognize homozygous or compound heterozygous truncating mutations in ALMS1 in four other children with high levels of postnatal cardiomyocyte proliferation. Alms1 mRNA knockdown increases multiple markers of proliferation in cardiomyocytes, the percentage of cardiomyocytes in G2/M phases, and the number of cardiomyocytes by 10% in cultured cells. Homozygous Alms1-mutant mice have increased cardiomyocyte proliferation at 2 weeks postnatal compared with wild-type littermates. We conclude that deficiency of Alström protein impairs postnatal cardiomyocyte cell cycle arrest.

Mitchell-Riley Syndrome: A Novel Mutation in RFX6 Gene

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Marta Zegre Amorim

2015-01-01

Full Text Available A novel RFX6 homozygous missense mutation was identified in an infant with Mitchell-Riley syndrome. The most common features of Mitchell-Riley syndrome were present, including severe neonatal diabetes associated with annular pancreas, intestinal malrotation, gallbladder agenesis, cholestatic disease, chronic diarrhea, and severe intrauterine growth restriction. Perijejunal tissue similar to pancreatic tissue was found in the submucosa, a finding that has not been previously reported in this syndrome. This case associating RFX6 mutation with structural and functional pancreatic abnormalities reinforces the RFX6 gene role in pancreas development and β-cell function, adding information to the existent mutation databases.

The ter mutation in the rat Dnd1 gene initiates gonadal teratomas and infertility in both genders.

Science.gov (United States)

Northrup, Emily; Zschemisch, Nils-Holger; Eisenblätter, Regina; Glage, Silke; Wedekind, Dirk; Cuppen, Edwin; Dorsch, Martina; Hedrich, Hans-Jürgen

2012-01-01

A spontaneous mutation leading to the formation of congenital ovarian and testicular tumors was detected in the WKY/Ztm rat strain. The histological evaluation revealed derivatives from all three germ layers, thereby identifying these tumors as teratomas. Teratocarcinogenesis was accompanied by infertility and the underlying mutation was termed ter. Linkage analysis of 58 (WKY-ter×SPRD-Cu3) F2 rats associated the ter mutation with RNO18 (LOD = 3.25). Sequencing of candidate genes detected a point mutation in exon 4 of the dead-end homolog 1 gene (Dnd1), which introduces a premature stop codon assumed to cause a truncation of the Dnd1 protein. Genotyping of the recessive ter mutation revealed a complete penetrance of teratocarcinogenesis and infertility in homozygous ter rats of both genders. Morphologically non-tumorous testes of homozygous ter males were reduced in both size and weight. This testicular malformation was linked to a lack of spermatogenesis using immunohistochemical and histological staining. Our WKY-Dnd1(ter)/Ztm rat is a novel animal model to investigate gonadal teratocarcinogenesis and the molecular mechanisms involved in germ cell development of both genders.

Mutation induction by heavy ions

Science.gov (United States)

Kiefer, J.; Stoll, U.; Schneider, E.

1994-10-01

Mutation induction by heavy ions is compared in yeast and mammalian cells. Since mutants can only be recovered in survivors the influence of inactivation cross sections has to be taken into account. It is shown that both the size of the sensitive cellular site as well as track structure play an important role. Another parameter which influences the probability of mutation induction is repair: Contrary to naive assumptions primary radiation damage does not directly lead to mutations but requires modification to reconstitute the genetic machinery so that mutants can survive. The molecular structure of mutations was analyzed after exposure to deuterons by amplification with the aid of polymerase chain reaction. The results-although preliminary-demonstrate that even with densely ionizing particles a large fraction does not carry big deletions which suggests that point mutations may also be induced by heavy ions.

CBS mutations and MTFHR SNPs causative of hyperhomocysteinemia in Pakistani children.

Science.gov (United States)

Ibrahim, Shahnaz; Maqbool, Saadia; Azam, Maleeha; Iqbal, Mohammad Perwaiz; Qamar, Raheel

2018-03-29

Three index patients with hyperhomocysteinemia and ocular anomalies were screened for cystathionine beta synthase (CBS) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms. Genotyping of hyperhomocysteinemia associated MTHFR polymorphisms C677T (rs1801133) and A1298C (rs1801131) was done by PCR-restriction fragment length polymorphism. Sanger sequencing was performed for CBS exonic sequences along with consensus splice sites. In the case of MTHFR polymorphisms, all the patients were heterozygous CT for the single nucleotide polymorphism (SNP) C677T and were therefore carriers of the risk allele (T), while the patients were homozygous CC for the risk genotype of the SNP A1298C. CBS sequencing resulted in the identification of two novel mutations, a missense change (c.467T>C; p.Leu156Pro) in exon 7 and an in-frame deletion (c.808_810del; p.Glu270del) in exon 10. In addition, a recurrent missense mutation (c.770C>T; p.Thr257Met) in exon 10 of the gene was also identified. The mutations were present homozygously in the patients and were inherited from the carrier parents. This is the first report from Pakistan where novel as well as recurrent CBS mutations causing hyperhomocysteinemia and lens dislocation in three patients from different families are being reported with the predicted effect of the risk allele of the MTHFR SNP in causing hyperhomocysteinemia.

Compound heterozygous ASPM mutations in Pakistani MCPH families

DEFF Research Database (Denmark)

Muhammad, Farooq; Mahmood Baig, Shahid; Hansen, Lars

2009-01-01

Autosomal recessive primary microcephaly (MCPH) is characterized by reduced head circumference (50% of all reported families. In spite of the high frequency of MCPH in Pakistan only one case of compound heterozygosity for mutations in ASPM has been reported yet. In this large MCPH study we...... confirmed compound heterozygosity in two and homozygous mutations in 20 families, respectively, showing that up to 10% of families with MCPH caused by ASPM are compound heterozygous. In total we identified 16 different nonsense or frameshift mutations of which 12 were novel thereby increasing the number...... of mutations in ASPM significantly from 35 to 47. We found no correlation between the severity of the condition and the site of truncation. We suggest that the high frequency of compound heterozygosity observed in this study is taken into consideration as part of future genetic testing and counseling...

Exome Sequencing Identified a Recessive RDH12 Mutation in a Family with Severe Early-Onset Retinitis Pigmentosa

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Bo Gong

2015-01-01

Full Text Available Retinitis pigmentosa (RP is the most important hereditary retinal disease caused by progressive degeneration of the photoreceptor cells. This study is to identify gene mutations responsible for autosomal recessive retinitis pigmentosa (arRP in a Chinese family using next-generation sequencing technology. A Chinese family with 7 members including two individuals affected with severe early-onset RP was studied. All patients underwent a complete ophthalmic examination. Exome sequencing was performed on a single RP patient (the proband of this family and direct Sanger sequencing on other family members and normal controls was followed to confirm the causal mutations. A homozygous mutation c.437Thomozygous mutation was detected in the two affected patients, but not present in other family members and 600 normal controls. Another three normal members in the family were found to carry this heterozygous missense mutation. Our results emphasize the importance of c.437Tmutation in the pathogenesis and clinical diagnosis of RP.

Inactivation of the DNA repair gene O6-methylguanine-DNA methyltransferase by promoter hypermethylation is associated with G to A mutations in K-ras in colorectal tumorigenesis.

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Esteller, M; Toyota, M; Sanchez-Cespedes, M; Capella, G; Peinado, M A; Watkins, D N; Issa, J P; Sidransky, D; Baylin, S B; Herman, J G

2000-05-01

O6-methylguanine DNA methyltransferase (MGMT) is a DNA repair protein that removes mutagenic and cytotoxic adducts from the O6 position of guanine. O6-methylguanine mispairs with thymine during replication, and if the adduct is not removed, this results in conversion from a guanine-cytosine pair to an adenine-thymine pair. In vitro assays show that MGMT expression avoids G to A mutations and MGMT transgenic mice are protected against G to A transitions at ras genes. We have recently demonstrated that the MGMT gene is silenced by promoter methylation in many human tumors, including colorectal carcinomas. To study the relevance of defective MGMT function by aberrant methylation in relation to the presence of K-ras mutations, we studied 244 colorectal tumor samples for MGMT promoter hypermethylation and K-ras mutational status. Our results show a clear association between the inactivation of MGMT by promoter hypermethylation and the appearance of G to A mutations at K-ras: 71% (36 of 51) of the tumors displaying this particular type of mutation had abnormal MGMT methylation, whereas only 32% (12 of 37) of those with other K-ras mutations not involving G to A transitions and 35% (55 of 156) of the tumors without K-ras mutations demonstrated MGMT methylation (P = 0.002). In addition, MGMT loss associated with hypermethylation was observed in the small adenomas, including those that do not yet contain K-ras mutations. Hypermethylation of other genes such as p16INK4a and p14ARF was not associated with either MGMT hypermethylation or K-ras mutation. Our data suggest that epigenetic silencing of MGMT by promoter hypermethylation may lead to a particular genetic change in human cancer, specifically G to A transitions in the K-ras oncogene.

Tumor suppressor genes that escape from X-inactivation contribute to cancer sex bias

OpenAIRE

Dunford, Andrew; Weinstock, David M.; Savova, Virginia; Schumacher, Steven E.; Cleary, John P.; Yoda, Akinori; Sullivan, Timothy J.; Hess, Julian M.; Gimelbrant, Alexander A.; Beroukhim, Rameen; Lawrence, Michael S.; Getz, Gad; Lane, Andrew A.

2016-01-01

There is a striking and unexplained male predominance across many cancer types. A subset of X chromosome (chrX) genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative “Escape from X-Inactivation Tumor Suppressor” (EXITS) genes, we compared somatic alterations from >4100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) chrX genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) ...

A/α-specific effect of the mms3 mutation on ultraviolet mutagenesis in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Martin, P.; Prakash, L.; Prakash, S.

1981-01-01

A new gene involved in error-prone repair of ultraviolet (uv) damage has been identified in Saccharomyces cerevisiae by the mms3-1 mutation. Uv-induced reversion is reduced in diploids that are homozygous for mms3-1, only if they are also heterozygous (MATa/MATα) at the mating type locus. The mms3-1 mutation has no effect on uv-induced reversion either in haploids or MATa/MATα or MATα/MATα diploids. The mutation confers sensitivity to uv and methyl methane sulfonate in both haploids and diploids. Even though mutation induction by uv is restored to wild-type levels in MATa/MATa mms3-1/mms3-1 or MATα/MATα mms3-1/mms3-1 diploids, such strains still retain sensitivity to the lethal effects of uv. Survival after uv irradiation in mms3-1 rad double mutant combinations indicates that mms3-1 is epistatic to rad6-1 whereas non-epistatic interactions are observed with rad3 and rad52 mutants. When present in the homozygous state in MATa/MATα his1-1/his1-315 heteroallelic diploids, mms3-1 was found to lower uv-induced mitotic recombination

Acral peeling skin syndrome associated with a novel CSTA gene mutation.

Science.gov (United States)

Muttardi, K; Nitoiu, D; Kelsell, D P; O'Toole, E A; Batta, K

2016-06-01

Acral peeling skin syndrome (APSS) is a rare autosomal recessive condition, characterized by asymptomatic peeling of the skin of the hands and feet, often linked to mutations in the gene TGM5. However, more recently recessive loss of function mutations in CSTA, encoding cystatin A, have been linked with APSS and exfoliative ichthyosis. We describe the clinical features in two sisters with APSS, associated with a novel large homozygous deletion encompassing exon 1 of CSTA. © 2015 British Association of Dermatologists.

WNT10A missense mutation associated with a complete odonto-onycho-dermal dysplasia syndrome.

Science.gov (United States)

Nawaz, Sadia; Klar, Joakim; Wajid, Muhammad; Aslam, Muhammad; Tariq, Muhammad; Schuster, Jens; Baig, Shahid Mahmood; Dahl, Niklas

2009-12-01

Wnt signalling is one of a few pathways that are crucial for controlling genetic programs during embryonic development as well as in adult tissues. WNT10A is expressed in the skin and epidermis and it has shown to be critical for the development of ectodermal appendages. A nonsense mutation in WNT10A was recently identified in odonto-onycho-dermal dysplasia (OODD; MIM 257980), a rare syndrome characterised by severe hypodontia, nail dystrophy, smooth tongue, dry skin, keratoderma and hyperhydrosis of palms and soles. We identified a large consanguineous Pakistani pedigree comprising six individuals affected by a complete OODD syndrome. Autozygosity mapping using SNP array analysis showed that the affected individuals are homozygous for the WNT10A gene region. Subsequent mutation screening showed a homozygous c.392C>T transition in exon 3 of WNT10A, which predicts a p.A131V substitution in a conserved alpha-helix domain. We report here on the first inherited missense mutation in WNT10A with associated ectodermal features.

Novel USH2A compound heterozygous mutations cause RP/USH2 in a Chinese family.

Science.gov (United States)

Liu, Xiaowen; Tang, Zhaohui; Li, Chang; Yang, Kangjuan; Gan, Guanqi; Zhang, Zibo; Liu, Jingyu; Jiang, Fagang; Wang, Qing; Liu, Mugen

2010-03-17

To identify the disease-causing gene in a four-generation Chinese family affected with retinitis pigmentosa (RP). Linkage analysis was performed with a panel of microsatellite markers flanking the candidate genetic loci of RP. These loci included 38 known RP genes. The complete coding region and exon-intron boundaries of Usher syndrome 2A (USH2A) were sequenced with the proband DNA to screen the disease-causing gene mutation. Restriction fragment length polymorphism (RFLP) analysis and direct DNA sequence analysis were done to demonstrate co-segregation of the USH2A mutations with the family disease. One hundred normal controls were used without the mutations. The disease-causing gene in this Chinese family was linked to the USH2A locus on chromosome 1q41. Direct DNA sequence analysis of USH2A identified two novel mutations in the patients: one missense mutation p.G1734R in exon 26 and a splice site mutation, IVS32+1G>A, which was found in the donor site of intron 32 of USH2A. Neither the p.G1734R nor the IVS32+1G>A mutation was found in the unaffected family members or the 100 normal controls. One patient with a homozygous mutation displayed only RP symptoms until now, while three patients with compound heterozygous mutations in the family of study showed both RP and hearing impairment. This study identified two novel mutations: p.G1734R and IVS32+1G>A of USH2A in a four-generation Chinese RP family. In this study, the heterozygous mutation and the homozygous mutation in USH2A may cause Usher syndrome Type II or RP, respectively. These two mutations expand the mutant spectrum of USH2A.

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.

Germline RAD51B truncating mutation in a family with cutaneous melanoma

DEFF Research Database (Denmark)

Wadt, Karin A W; Aoude, Lauren G; Golmard, Lisa

2015-01-01

Known melanoma predisposition genes only account for around 40% of high-density melanoma families. Other rare mutations are likely to play a role in melanoma predisposition. RAD51B plays an important role in DNA repair through homologous recombination, and inactivation of RAD51B has been implicated...... in tumorigenesis. Thus RAD51B is a good candidate melanoma susceptibility gene, and previously, a germline splicing mutation in RAD51B has been identified in a family with early-onset breast cancer. In order to find genetic variants associated with melanoma predisposition, whole-exome sequencing was carried out...... on blood samples from a three-case cutaneous melanoma family. We identified a novel germline RAD51B nonsense mutation, and we demonstrate reduced expression of RAD51B in melanoma cells indicating inactivation of RAD51B. This is only the second report of a germline truncating RAD51B mutation. While...

Juvenile-Onset Diabetes and Congenital Cataract: “Double-Gene” Mutations Mimicking a Syndromic Diabetes Presentation

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Caroline Lenfant

2017-11-01

Full Text Available Monogenic forms of diabetes may account for 1–5% of all cases of diabetes, and may occur in the context of syndromic presentations. We investigated the case of a girl affected by insulin-dependent diabetes, diagnosed at 6 years old, associated with congenital cataract. Her consanguineous parents and her four other siblings did not have diabetes or cataract, suggesting a recessive syndrome. Using whole exome sequencing of the affected proband, we identified a heterozygous p.R825Q ABCC8 mutation, located at the exact same amino-acid position as the p.R825W recurring diabetes mutation, hence likely responsible for the diabetes condition, and a homozygous p.G71S mutation in CRYBB1, a gene known to be responsible for congenital cataract. Both mutations were predicted to be damaging and were absent or extremely rare in public databases. Unexpectedly, we found that the mother was also homozygous for the CRYBB1 mutation, and both the mother and one unaffected sibling were heterozygous for the ABCC8 mutation, suggesting incomplete penetrance of both mutations. Incomplete penetrance of ABCC8 mutations is well documented, but this is the first report of an incomplete penetrance of a CRYBB1 mutation, manifesting between susceptible subjects (unaffected mother vs. affected child and to some extent within the patient herself, who had distinct cataract severities in both eyes. Our finding illustrates the importance of family studies to unmask the role of confounding factors such as double-gene mutations and incomplete penetrance that may mimic monogenic syndromes including in the case of strongly evocative family structure with consanguinity.

Immunodeficiency associated with FCN3 mutation and ficolin-3 deficiency

DEFF Research Database (Denmark)

Munthe-Fog, Lea; Hummelshøj, Tina; Honoré, Christian

2009-01-01

Ficolin-3, encoded by the FCN3 gene and expressed in the lung and liver, is a recognition molecule in the lectin pathway of the complement system. Heterozygosity for an FCN3 frameshift mutation (rs28357092), leading to a distortion of the C-terminal end of the molecule, occurs in people without...... disease (allele frequency among whites, 0.01). We describe a patient with recurrent infections who was homozygous for this mutation, who had undetectable serum levels of ficolin-3, and who had a deficiency in ficolin-3-dependent complement activation....

A mutation in KIF7 is responsible for the autosomal recessive syndrome of macrocephaly, multiple epiphyseal dysplasia and distinctive facial appearance

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Ali Bassam R

2012-05-01

Full Text Available Abstract Background We previously reported the existence of a unique autosomal recessive syndrome consisting of macrocephaly, multiple epiphyseal dysplasia and distinctive facial appearance mapping to chromosome 15q26. Methods In this manuscript, we have used whole exome sequencing on two affected members of a consanguineous family with this condition and carried out detailed bioinformatics analysis to elucidate the causative mutation. Results Our analysis resulted in the identification of a homozygous p.N1060S missense mutation in a highly conserved residue in KIF7, a regulator of Hedgehog signaling that has been recently found to be causing Joubert syndrome, fetal hydrolethalus and acrocallosal syndromes. The phenotype in our patients partially overlaps with the phenotypes associated with those syndromes but they also exhibit some distinctive features including multiple epiphyseal dysplasia. Conclusions We report the first missense homozygous disease-causing mutation in KIF7 and expand the clinical spectrum associated with mutations in this gene to include multiple epiphyseal dysplasia. The missense nature of the mutation might account for the unique presentation in our patients.

A novel lipoprotein lipase gene missense mutation in Chinese patients with severe hypertriglyceridemia and pancreatitis

Science.gov (United States)

2014-01-01

Background Alterations or mutations in the lipoprotein lipase (LPL) gene contribute to severe hypertriglyceridemia (HTG). This study reported on two patients in a Chinese family with LPL gene mutations and severe HTG and acute pancreatitis. Methods Two patients with other five family members were included in this study for DNA-sequences of hyperlipidemia-related genes (such as LPL, APOC2, APOA5, LMF1, and GPIHBP1) and 43 healthy individuals and 70 HTG subjects were included for the screening of LPL gene mutations. Results Both patients were found to have a compound heterozygote for a novel LPL gene mutation (L279V) and a known mutation (A98T). Furthermore, one HTG subject out of 70 was found to carry this novel LPL L279V mutation. Conclusions The data from this study showed that compound heterozygote mutations of A98T and L279V inactivate lipoprotein lipase enzymatic activity and contribute to severe HTG and acute pancreatitis in two Chinese patients. Further study will investigate how these LPL gene mutations genetically inactivate the LPL enzyme. PMID:24646025

NMD Microarray Analysis for Rapid Genome-Wide Screen of Mutated Genes in Cancer

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Maija Wolf

2005-01-01

Full Text Available Gene mutations play a critical role in cancer development and progression, and their identification offers possibilities for accurate diagnostics and therapeutic targeting. Finding genes undergoing mutations is challenging and slow, even in the post-genomic era. A new approach was recently developed by Noensie and Dietz to prioritize and focus the search, making use of nonsense-mediated mRNA decay (NMD inhibition and microarray analysis (NMD microarrays in the identification of transcripts containing nonsense mutations. We combined NMD microarrays with array-based CGH (comparative genomic hybridization in order to identify inactivation of tumor suppressor genes in cancer. Such a “mutatomics” screening of prostate cancer cell lines led to the identification of inactivating mutations in the EPHB2 gene. Up to 8% of metastatic uncultured prostate cancers also showed mutations of this gene whose loss of function may confer loss of tissue architecture. NMD microarray analysis could turn out to be a powerful research method to identify novel mutated genes in cancer cell lines, providing targets that could then be further investigated for their clinical relevance and therapeutic potential.

Alpha-tubulin missense mutations correlate with antimicrotubule drug resistance in Eleusine indica.

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Yamamoto, E; Zeng, L; Baird, W V

1998-02-01

Dinitroaniline herbicides are antimicrotubule drugs that bind to tubulins and inhibit polymerization. As a result of repeated application of dinitroaniline herbicides, highly resistant and intermediately resistant biotypes of goosegrass (Eleusine indica) developed in previously wild-type populations. Three alpha-tubulin cDNA classes (designated TUA1, TUA2, and TUA3) were isolated from each biotype. Nucleotide differences between the susceptible and the resistant (R) alpha-tubulins were identified in TUA1 and TUA2. The most significant differences were missense mutations that occurred in TUA1 of the R and intermediately resistant (I) biotypes. Such mutations convert Thr-239 to Ile in the R biotype and Met-268 to Thr in the I biotype. These amino acid substitutions alter hydrophobicity; therefore, they may alter the dinitroaniline binding property of the protein. These mutations were correlated with the dinitroaniline response phenotypes (Drp). Plants homozygous for susceptibility possessed the wild-type TUA1 allele; plants homozygous for resistance possessed the mutant tua1 allele; and plants heterozygous for susceptibility possessed both wild-type and mutant alleles. Thus, we conclude that TUA1 is at the Drp locus. Using polymerase chain reaction primer-introduced restriction analysis, we demonstrated that goosegrass genomic DNA can be diagnosed for Drp alleles. Although not direct proof, these results suggest that a mutation in an alpha-tubulin gene confers resistance to dinitroanilines in goosegrass.

NDUFA4 Mutations Underlie Dysfunction of a Cytochrome c Oxidase Subunit Linked to Human Neurological Disease

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Robert D.S. Pitceathly

2013-06-01

Full Text Available The molecular basis of cytochrome c oxidase (COX, complex IV deficiency remains genetically undetermined in many cases. Homozygosity mapping and whole-exome sequencing were performed in a consanguineous pedigree with isolated COX deficiency linked to a Leigh syndrome neurological phenotype. Unexpectedly, affected individuals harbored homozygous splice donor site mutations in NDUFA4, a gene previously assigned to encode a mitochondrial respiratory chain complex I (NADH:ubiquinone oxidoreductase subunit. Western blot analysis of denaturing gels and immunocytochemistry revealed undetectable steady-state NDUFA4 protein levels, indicating that the mutation causes a loss-of-function effect in the homozygous state. Analysis of one- and two-dimensional blue-native polyacrylamide gels confirmed an interaction between NDUFA4 and the COX enzyme complex in control muscle, whereas the COX enzyme complex without NDUFA4 was detectable with no abnormal subassemblies in patient muscle. These observations support recent work in cell lines suggesting that NDUFA4 is an additional COX subunit and demonstrate that NDUFA4 mutations cause human disease. Our findings support reassignment of the NDUFA4 protein to complex IV and suggest that patients with unexplained COX deficiency should be screened for NDUFA4 mutations.

Prevalence of GJB2 Mutations in Affected Individuals from United Arab Emirates with Autosomal Recessive Nonsyndromic Hearing Loss.

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Tlili, Abdelaziz; Al Mutery, Abdullah; Kamal Eddine Ahmad Mohamed, Walaa; Mahfood, Mona; Hadj Kacem, Hassen

2017-11-01

Mutations in the gap junction protein beta 2 (GJB2) gene are responsible for more cases of nonsyndromic recessive hearing loss than any other gene. The purpose of our study was to evaluate the prevalence of GJB2 mutations among affected individuals from United Arab Emirates (UAE). There were 50 individuals diagnosed with hereditary hearing loss and 120 healthy individuals enrolled in the study. The Sanger sequencing method was used to screen the GJB2 coding region in all affected individuals. The c.-1G>A variant was determined by the polymerase chain reaction-restriction fragment length polymorphism method in normal individuals. Nine cases with bi-allelic mutations and three cases with mono-allelic mutations were detected in 12 out of 50 patients (24%). The homozygous mutation c.35delG was identified as the cause of hearing loss in six participants (12%). The mutation c.506G>A was identified in three affected individuals (6%). The allelic frequency (14%) and low percentage of individuals that were homozygous (2%) for the c.35delG mutation suggest that there are other genes responsible for nonsyndromic deafness in the UAE population. The results reported here are a preliminary step in collecting epidemiological data regarding autosomal recessive nonsyndromic hearing loss related to GJB2 gene mutations among the UAE population. The c.35delG mutation of the GJB2 gene is the most frequently seen causative mutation in the UAE and is followed by the p.Cys169Tyr mutation.

[Mechanisms of endogenous drug resistance acquisition by spontaneous chromosomal gene mutation].

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Fukuda, H; Hiramatsu, K

1997-05-01

Endogenous resistance in bacteria is caused by a change or loss of function and generally genetically recessive. However, this type of resistance acquisition are now prevalent in clinical setting. Chromosomal genes that afford endogenous resistance are the genes correlated with the target of the drug, the drug inactivating enzymes, and permeability of the molecules including the antibacterial agents. Endogenous alteration of the drug target are mediated by the spontaneous mutation of their structural gene. This mutation provides much lower affinity of the drugs for the target. Gene expression of the inactivating enzymes, such as class C beta-lactamase, is generally regulated by regulatory genes. Spontaneous mutations in the regulatory genes cause constitutive enzyme production and provides the resistant to the agent which is usually stable for such enzymes. Spontaneous mutation in the structural gene gives the enzyme extra-spectrum substrate specificity, like ESBL (Extra-Spectrum-beta-Lactamase). Expression of structural genes encoding the permeability systems are also regulated by some regulatory genes. The spontaneous mutation of the regulatory genes reduce an amount of porin protein. This mutation causes much lower influx of the drug in the cell. Spontaneous mutation in promoter region of the structural gene of efflux protein was observed. This mutation raised the gene transcription and overproduced efflux protein. This protein progresses the drug efflux from the cell.

Simultaneous Occurence of an Autosomal Dominant Inherited MSX1 Mutation and an X-linked Recessive Inherited EDA Mutation in One Chinese Family with Non-syndromic Oligodontia.

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Zhang, Xiao Xia; Wong, Sing Wai; Han, Dong; Feng, Hai Lan

2015-01-01

To describe the simultaneous occurence of an autosomal dominant inherited MSX1 mutation and an X-linked recessive inherited EDA mutation in one Chinese family with nonsyndromic oligodontia. Clinical data of characteristics of tooth agenesis were collected. MSX1 and EDA gene mutations were detected in a Chinese family of non-syndromic oligodontia. Mild hypodontia in the parents and severe oligodontia in the son was recorded. A novel missense heterozygous mutation c.517C>A (p.Arg173Ser) was detected in the MSX1 gene in the boy and the father. A homozygous missense mutation c.1001G>A (p.Arg334His) was detected in the EDA gene in the boy and the same mutant occurred heterozygously in the mother. Simultaneous occurence of two different gene mutations with different inheritence patterns, which both caused oligodontia, which occurred in one subject and in one family, was reported.

Prognostic value of X-chromosome inactivation in symptomatic female carriers of dystrophinopathy

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Juan-Mateu Jonàs

2012-10-01

Full Text Available Abstract Background Between 8% and 22% of female carriers of DMD mutations exhibit clinical symptoms of variable severity. Development of symptoms in DMD mutation carriers without chromosomal rearrangements has been attributed to skewed X-chromosome inactivation (XCI favouring predominant expression of the DMD mutant allele. However the prognostic use of XCI analysis is controversial. We aimed to evaluate the correlation between X-chromosome inactivation and development of clinical symptoms in a series of symptomatic female carriers of dystrophinopathy. Methods We reviewed the clinical, pathological and genetic features of twenty-four symptomatic carriers covering a wide spectrum of clinical phenotypes. DMD gene analysis was performed using MLPA and whole gene sequencing in blood DNA and muscle cDNA. Blood and muscle DNA was used for X-chromosome inactivation (XCI analysis thought the AR methylation assay in symptomatic carriers and their female relatives, asymptomatic carriers as well as non-carrier females. Results Symptomatic carriers exhibited 49.2% more skewed XCI profiles than asymptomatic carriers. The extent of XCI skewing in blood tended to increase in line with the severity of muscle symptoms. Skewed XCI patterns were found in at least one first-degree female relative in 78.6% of symptomatic carrier families. No mutations altering XCI in the XIST gene promoter were found. Conclusions Skewed XCI is in many cases familial inherited. The extent of XCI skewing is related to phenotype severity. However, the assessment of XCI by means of the AR methylation assay has a poor prognostic value, probably because the methylation status of the AR gene in muscle may not reflect in all cases the methylation status of the DMD gene.

Same β-globin gene mutation is present on nine different β-thalassemia chromosomes in a Sardinian population

International Nuclear Information System (INIS)

Pirastu, M.; Galanello, R.; Doherty, M.A.; Tuveri, T.; Cao, A.; Kan, Y.W.

1987-01-01

The predominant β-thalassemia in Sardinia is the β 0 type in which no β-globin chains are synthesized in the homozygous state. The authors determined the β-thalassemia mutations in this population by the oligonucleotide-probe method and defined the chromosome haplotypes on which the mutation resides. The same β/sup 39(CAG→TAG)/ nonsense mutation was found on nine different chromosome haplotypes. Although this mutation may have arisen more than once, the multiple haplotypes could also be generated by crossing over and gene conversion events. These findings underscore the frequency of mutational events in the β-globin gene region

Analysis of HFE and non-HFE gene mutations in Brazilian patients with hemochromatosis.

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Bittencourt, Paulo Lisboa; Marin, Maria Lúcia Carnevale; Couto, Cláudia Alves; Cançado, Eduardo Luiz Rachid; Carrilho, Flair José; Goldberg, Anna Carla

2009-01-01

Approximately one-half of Brazilian patients with hereditary hemochromatosis (HH) are neither homozygous for the C282Y mutation nor compound heterozygous for the H63D and C282Y mutations that are associated with HH in Caucasians. Other mutations have been described in the HFE gene as well as in genes involved in iron metabolism, such as transferrin receptor 2 (TfR2) and ferroportin 1 (SCL40A1). To evaluate the role of HFE, TfR2 and SCL40A1 mutations in Brazilian subjects with HH. Nineteen male subjects (median age 42 [range: 20-72] years) with HH were evaluated using the Haemochromatosis StripAssay A. This assay is capable of detecting twelve HFE mutations, which are V53M, V59M, H63D, H63H, S65C, Q127H, P160delC, E168Q, E168X, W169X, C282Y and Q283, four TfR2 mutations, which are E60X, M172K, Y250X, AVAQ594-597del, and two SCL40A1 mutations, which are N144H and V162del. In our cohort, nine (47%) patients were homozygous for the C282Y mutation, two (11%) were heterozygous for the H63D mutation, and one each (5%) was either heterozygous for C282Y or compound heterozygous for C282Y and H63D. No other mutations in the HFE, TfR2 or SCL40A1 genes were observed in the studied patients. One-third of Brazilian subjects with the classical phenotype of HH do not carry HFE or other mutations that are currently associated with the disease in Caucasians. This observation suggests a role for other yet unknown mutations in the aforementioned genes or in other genes involved in iron homeostasis in the pathogenesis of HH in Brazil.

Analysis of HFE and non-HFE gene mutations in Brazilian patients with hemochromatosis

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Paulo Lisboa Bittencourt

2009-01-01

Full Text Available BACKGROUND: Approximately one-half of Brazilian patients with hereditary hemochromatosis (HH are neither homozygous for the C282Y mutation nor compound heterozygous for the H63D and C282Y mutations that are associated with HH in Caucasians. Other mutations have been described in the HFE gene as well as in genes involved in iron metabolism, such as transferrin receptor 2 (TfR2 and ferroportin 1 (SCL40A1. AIMS: To evaluate the role of HFE, TfR2 and SCL40A1 mutations in Brazilian subjects with HH. PATIENTS AND METHODS: Nineteen male subjects (median age 42 [range: 20-72] years with HH were evaluated using the Haemochromatosis StripAssay A®. This assay is capable of detecting twelve HFE mutations, which are V53M, V59M, H63D, H63H, S65C, Q127H, P160delC, E168Q, E168X, W169X, C282Y and Q283, four TfR2 mutations, which are E60X, M172K, Y250X, AVAQ594-597del, and two SCL40A1 mutations, which are N144H and V162del. RESULTS: In our cohort, nine (47% patients were homozygous for the C282Y mutation, two (11% were heterozygous for the H63D mutation, and one each (5% was either heterozygous for C282Y or compound heterozygous for C282Y and H63D. No other mutations in the HFE, TfR2 or SCL40A1 genes were observed in the studied patients. CONCLUSIONS: One-third of Brazilian subjects with the classical phenotype of HH do not carry HFE or other mutations that are currently associated with the disease in Caucasians. This observation suggests a role for other yet unknown mutations in the aforementioned genes or in other genes involved in iron homeostasis in the pathogenesis of HH in Brazil.

Biallelic PMS2 Mutation and Heterozygous DICER1 Mutation Presenting as Constitutional Mismatch Repair Deficiency With Corpus Callosum Agenesis: Case Report and Review of Literature.

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Cheyuo, Cletus; Radwan, Walid; Ahn, Janice; Gyure, Kymberly; Qaiser, Rabia; Tomboc, Patrick

2017-10-01

Constitutional mismatch repair deficiency syndrome is a cancer predisposition syndrome caused by autosomal recessive biallelic (homozygous) germline mutations in the mismatch repair genes (MLH1, MSH2, MSH6, and PMS2). The clinical spectrum includes neoplastic and non-neoplastic manifestations. We present the case of a 7-year-old boy who presented with T-lymphoblastic lymphoma and glioblastoma, together with non-neoplastic manifestations including corpus callosum agenesis, arachnoid cyst, developmental venous anomaly, and hydrocephalus. Gene mutation analysis revealed pathogenic biallelic mutations of PMS2 and heterozygous DICER1 variant predicted to be pathogenic. This report is the first to allude to a possible interaction of the mismatch repair system with DICER1 to cause corpus callosum agenesis.

Multiple Patterns of FHIT Gene Homozygous Deletion in Egyptian Breast Cancer Patients

International Nuclear Information System (INIS)

Ismail, H.M.S.; Zakhary, N.I.; Medhat, A.M.; Karim, A.M.

2011-01-01

Fragile histidine triad (FHIT) gene encodes a putative tumour suppressor protein. Loss of Fhit protein in cancer is attributed to different genetic alterations that affect the FHIT gene structure. In this study, we investigated the pattern of homozygous deletion that target the FHIT gene exons 3 to 9 genomic structure in Egyptian breast cancer patients. We have found that 65% (40 out of 62) of the cases exhibited homozygous deletion in at least one FHIT exon. The incidence of homozygous deletion was not associated with patients clinico pathological parameters including patients age, tumour grade, tumour type, and lymph node involvement. Using correlation analysis, we have observed a strong correlation between homozygous deletions of exon 3 and exon 4 (P<0.0001). Deletions in exon 5 were positively correlated with deletions in exon 7 (P<0.0001), Exon 8 (P<0.027), and exon 9 (P=0.04). Additionally, a strong correlation was observed between exons 8 and exon 9 (P<0.0001).We conclude that FHIT gene exons are homozygously deleted at high frequency in Egyptian women population diagnosed with breast cancer. Three different patterns of homozygous deletion were observed in this population indicating different mechanisms of targeting FHIT gene genomic structure.

A homozygous FITM2 mutation causes a deafness-dystonia syndrome with motor regression and signs of ichthyosis and sensory neuropathy

DEFF Research Database (Denmark)

Zazo Seco, Celia; Castells-Nobau, Anna; Joo, Seol-Hee

2017-01-01

A consanguineous family from Pakistan was ascertained to have a novel deafness-dystonia syndrome with motor regression, ichthyosis-like features and signs of sensory neuropathy. By applying a combined strategy of linkage analysis and whole-exome sequencing in the presented family, a homozygous no...

Disruption of the IS6-AID linker affects voltage-gated calcium channel inactivation and facilitation.

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Findeisen, Felix; Minor, Daniel L

2009-03-01

Two processes dominate voltage-gated calcium channel (Ca(V)) inactivation: voltage-dependent inactivation (VDI) and calcium-dependent inactivation (CDI). The Ca(V)beta/Ca(V)alpha(1)-I-II loop and Ca(2+)/calmodulin (CaM)/Ca(V)alpha(1)-C-terminal tail complexes have been shown to modulate each, respectively. Nevertheless, how each complex couples to the pore and whether each affects inactivation independently have remained unresolved. Here, we demonstrate that the IS6-alpha-interaction domain (AID) linker provides a rigid connection between the pore and Ca(V)beta/I-II loop complex by showing that IS6-AID linker polyglycine mutations accelerate Ca(V)1.2 (L-type) and Ca(V)2.1 (P/Q-type) VDI. Remarkably, mutations that either break the rigid IS6-AID linker connection or disrupt Ca(V)beta/I-II association sharply decelerate CDI and reduce a second Ca(2+)/CaM/Ca(V)alpha(1)-C-terminal-mediated process known as calcium-dependent facilitation. Collectively, the data strongly suggest that components traditionally associated solely with VDI, Ca(V)beta and the IS6-AID linker, are essential for calcium-dependent modulation, and that both Ca(V)beta-dependent and CaM-dependent components couple to the pore by a common mechanism requiring Ca(V)beta and an intact IS6-AID linker.

Mutations induced by X-radiation in the yeast Schizosaccharomyces pombe

International Nuclear Information System (INIS)

Loprieno, N.; Barale, R.; Baroncelli, S.; Cammellini, A.; Melani, M.; Nieri, R.; Nozzolini, M.; Rossi, A.M.; Pisa Univ.

1975-01-01

Experiments on strains of yeast with different genetic backgrounds were done to evaluate the kinetics of inactivation and mutation induction by X-radiation. A system of forward mutation induction in five loci was used and a specific mutation rate was evaluated for the wild type. From a comparison of observations with wild type and radiation-sensitive strains, it may be assumed that in this yeast, mutations are mainly the result of a repair-active process. The range of genotypic and phenotypic influence upon the specific locus mutation rate was evaluated with appropriate biological material and experiments

[Research progress of mutational spectrum and pathophysiology of WFS1 gene in Wolfram syndrome and nonsyndromic low frequency sensorineural hearing loss].

Science.gov (United States)

Shi, S M; Han, Y H; Wang, H B

2016-09-07

Compound homozygous or heterozygous mutations in WFS 1 can lead to autosomal recessive Wolfram syndrome (WS), and heterozygous mutations in WFS 1 can lead to autosomal dominant non-syndromic low frequency sensorineural hearing loss (LFSNHL). In addition, mutations in the WFS region has relationship with diabetes and psychiatric diseases. In this paper, we provide an overview of genetic research with different phenotypes, including WS and LFSNHL.

Immuno-inhibitory PD-L1 can be induced by a peptidoglycan/NOD2 mediated pathway in primary monocytic cells and is deficient in Crohn's patients with homozygous NOD2 mutations.

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Hewitt, Rachel E; Pele, Laetitia C; Tremelling, Mark; Metz, Andrew; Parkes, Miles; Powell, Jonathan J

2012-05-01

Peptidoglycan (PGN) is a ubiquitous bacterial membrane product that, despite its well known pro-inflammatory properties, has also been invoked in immuno-tolerance of the gastrointestinal tract. PGN-induced mucosal IL-10 secretion and downregulation of Toll like receptors are potential mechanisms of action in the gut but there are few data on tolerogenic adaptive immune responses and PGN. Here, using blood-derived mononuclear cells, we showed that PGN induced marked cell surface expression of PD-L1 but not PD-L2 or CD80/CD86, and specifically in the CD14(+) monocytic fraction. This was reproduced at the gene level with rapid induction (<4 h) and, unlike for LPS stimulation, was still sustained at 24 h. Using transfected and native muramyl dipeptide (MDP), which is a cleavage product of PGN and a specific NOD2 agonist, in assays with wild type cells or those from patients with Crohn's disease carrying the Leu1007 frameshift mutation of NOD2, we showed that (i) both NOD2 dependent and independent signalling (appearing TLR2 mediated) occurred for PGN upregulation of PD-L1 (ii) upregulation is lost in response to MDP in patients with the homozygous mutation and (iii) PD-L1 upregulation was unaffected in patients with heterozygous mutations as previously reported for cytokine responses to MDP. The uptake of PGN and its cleavage products by the intestinal mucosa is well recognised and further work should consider PD-L1 upregulation as one potential mechanism of the commensal flora-driven intestinal immuno-tolerance. Indeed, recent work has shown that loss of PD-L1 signalling in the gut breaks CD8(+) T cell tolerance to self antigen and leads to severe autoimmune enteritis. Copyright © 2012 Elsevier Inc. All rights reserved.

Mutation of the regulatory phosphorylation site of tobacco nitrate reductase results in constitutive activation of the enzyme in vivo and nitrite accumulation.

Science.gov (United States)

Lillo, Cathrine; Lea, Unni S; Leydecker, Marie-Thérèse; Meyer, Christian

2003-09-01

In wild-type Nicotiana plumbaginifolia and other higher plants, nitrate reductase (NR) is rapidly inactivated/activated in response to dark/light transitions. Inactivation of NR is believed to be caused by phosphorylation at a special conserved regulatory Ser residue, Ser 521, and interactions with divalent cations and inhibitory 14-3-3 proteins. A transgenic N. plumbaginifolia line (S(521)) was constructed where the Ser 521 had been changed by site-directed mutagenesis into Asp. This mutation resulted in complete abolishment of inactivation in response to light/dark transitions or other treatments known to inactivate NR. During prolonged darkness, NR in wild-type plants is in the inactivated form, whereas NR in the S(521) line is always in the active form. Differences in degradation rate between NR from S(521) and lines with non-mutated NR were not found. Kinetic constants like Km values for NADH and NO3(-) were not changed, but a slightly different pH profile was observed for mutated NR as opposed to non-mutated NR. Under optimal growth conditions, the phenotype of the S(521) plants was not different from the wild type (WT). However, when plants were irrigated with high nitrate concentration, 150 mM, the transgenic plants accumulated nitrite in darkness, and young leaves showed chlorosis.

Charge immobilization of the voltage sensor in domain IV is independent of sodium current inactivation.

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Sheets, Michael F; Hanck, Dorothy A

2005-02-15

Recovery from fast inactivation in voltage-dependent Na+ channels is associated with a slow component in the time course of gating charge during repolarization (i.e. charge immobilization), which results from the slow movement of the S4 segments in domains III and IV (S4-DIII and S4-DIV). Previous studies have shown that the non-specific removal of fast inactivation by the proteolytic enzyme pronase eliminated charge immobilization, while the specific removal of fast inactivation (by intracellular MTSET modification of a cysteine substituted for the phenylalanine in the IFM motif, ICMMTSET, in the inactivation particle formed by the linker between domains III and IV) only reduced the amount of charge immobilization by nearly one-half. To investigate the molecular origin of the remaining slow component of charge immobilization we studied the human cardiac Na+ channel (hH1a) in which the outermost arginine in the S4-DIV, which contributes approximately 20% to total gating charge (Qmax), was mutated to a cysteine (R1C-DIV). Gating charge could be fully restored in R1C-DIV by exposure to extracellular MTSEA, a positively charged methanethiosulphonate reagent. The RIC-DIV mutation was combined with ICMMTSET to remove fast inactivation, and the gating currents of R1C-DIV-ICM(MTSET) were recorded before and after modification with MTSEAo. Prior to MTSEAo, the time course of the gating charge during repolarization (off-charge) was best described by a single fast time constant. After MTSEA, the off-charge had both fast and slow components, with the slow component accounting for nearly 35% of Qmax. These results demonstrate that the slow movement of the S4-DIV during repolarization is not dependent upon the normal binding of the inactivation particle.

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.

75 FR 6211 - Prospective Grant of Exclusive License: Purified Inactivated Dengue Tetravalent Vaccine...

Science.gov (United States)

2010-02-08

... Exclusive License: Purified Inactivated Dengue Tetravalent Vaccine Containing a Common 30 Nucleotide Deletion in the 3'-UTR of Dengue Types 1,2,3, and 4 AGENCY: National Institutes of Health, Public Health...., ``Development of Mutations Useful for Attenuating Dengue Viruses and Chimeric Dengue Viruses''-- European Patent...

Loss-of-function mutations in the thyrotropin receptor gene as a major determinant of hyperthyrotropinemia in a consanguineous community.

Science.gov (United States)

Tenenbaum-Rakover, Yardena; Grasberger, Helmut; Mamanasiri, Sunee; Ringkananont, Usanee; Montanelli, Lucia; Barkoff, Marla S; Dahood, Ahmad Mahameed-Hag; Refetoff, Samuel

2009-05-01

Resistance to TSH (RTSH) is a condition of impaired responsiveness of the thyroid gland to TSH, characterized by elevated serum TSH, low or normal thyroid hormone levels, and hypoplastic or normal-sized thyroid gland. The aim of the study was to evaluate the clinical course and the genotype-phenotype relationship of RTSH caused by two different TSH receptor (TSHR) gene mutations in a consanguineous population. We conducted a clinical and genetic investigation of 46 members of an extended family and 163 individuals living in the same town. In vitro functional studies of the mutant TSHRs were also performed. Two TSHR gene mutations (P68S and L653V) were identified in 33 subjects occurring as homozygous L653V (five subjects), heterozygous L653V (20 subjects), heterozygous P68S (four subjects), and compound heterozygous L653V/P68S (four subjects). With the exception of one individual with concomitant autoimmune thyroid disease, all homozygotes and compound heterozygotes presented with compensated RTSH (high TSH with free T(4) and T(3) in the normal range). Only nine of 24 heterozygotes had mild hyperthyrotropinemia. The L653V mutation resulted in a higher serum TSH concentration and showed a more severe in vitro abnormality than P68S. Haplotype analysis predicted a founder of the L653V six to seven generations earlier, whereas the P68S is older. Cross-sectional and prospective longitudinal studies indicate that TSH and T(4) concentrations remain stable over time. High frequency hyperthyrotropinemia in an Israeli Arab-Muslim consanguineous community is attributed to two inactivating TSHR gene mutations. Concordant genotype-phenotype was demonstrated clinically and by in vitro functional analysis. Retrospective and prospective studies indicate that in the absence of concomitant autoimmune thyroid disease, elevated TSH levels reflect stable compensated RTSH.

Regulation of Na+ channel inactivation by the DIII and DIV voltage-sensing domains.

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Hsu, Eric J; Zhu, Wandi; Schubert, Angela R; Voelker, Taylor; Varga, Zoltan; Silva, Jonathan R

2017-03-06

Functional eukaryotic voltage-gated Na + (Na V ) channels comprise four domains (DI-DIV), each containing six membrane-spanning segments (S1-S6). Voltage sensing is accomplished by the first four membrane-spanning segments (S1-S4), which together form a voltage-sensing domain (VSD). A critical Na V channel gating process, inactivation, has previously been linked to activation of the VSDs in DIII and DIV. Here, we probe this interaction by using voltage-clamp fluorometry to observe VSD kinetics in the presence of mutations at locations that have been shown to impair Na V channel inactivation. These locations include the DIII-DIV linker, the DIII S4-S5 linker, and the DIV S4-S5 linker. Our results show that, within the 10-ms timeframe of fast inactivation, the DIV-VSD is the primary regulator of inactivation. However, after longer 100-ms pulses, the DIII-DIV linker slows DIII-VSD deactivation, and the rate of DIII deactivation correlates strongly with the rate of recovery from inactivation. Our results imply that, over the course of an action potential, DIV-VSDs regulate the onset of fast inactivation while DIII-VSDs determine its recovery. © 2017 Hsu et al.

Two Independent Mutations in ADAMTS17 Are Associated with Primary Open Angle Glaucoma in the Basset Hound and Basset Fauve de Bretagne Breeds of Dog.

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James A C Oliver

Full Text Available Mutations in ADAMTS10 (CFA20 have previously been associated with primary open angle glaucoma (POAG in the Beagle and Norwegian Elkhound. The closely related gene, ADAMTS17, has also been associated with several different ocular phenotypes in multiple breeds of dog, including primary lens luxation and POAG. We investigated ADAMTS17 as a candidate gene for POAG in the Basset Hound and Basset Fauve de Bretagne dog breeds.We performed ADAMTS17 exon resequencing in three Basset Hounds and three Basset Fauve de Bretagne dogs with POAG. Identified variants were genotyped in additional sample cohorts of both breeds and dogs of other breeds to confirm their association with disease.All affected Basset Hounds were homozygous for a 19 bp deletion in exon 2 that alters the reading frame and is predicted to lead to a truncated protein. Fifty clinically unaffected Basset Hounds were genotyped for this mutation and all were either heterozygous or homozygous for the wild type allele. Genotyping of 223 Basset Hounds recruited for a different study revealed a mutation frequency of 0.081 and predicted frequency of affected dogs in the population to be 0.007. Based on the entire genotyping dataset the association statistic for the POAG-associated deletion was p = 1.26 x 10-10. All affected Basset Fauve de Bretagne dogs were homozygous for a missense mutation in exon 11 causing a glycine to serine amino acid substitution (G519S in the disintegrin-like domain of ADAMTS17 which is predicted to alter protein function. Unaffected Basset Fauve de Bretagne dogs were either heterozygous for the mutation (5/24 or homozygous for the wild type allele (19/24. Based on the entire genotyping dataset the association statistic for the POAG-associated deletion was p = 2.80 x 10-7. Genotyping of 85 dogs of unrelated breeds and 90 dogs of related breeds for this variant was negative.This report documents strong associations between two independent ADAMTS17 mutations and POAG in two

Two Independent Mutations in ADAMTS17 Are Associated with Primary Open Angle Glaucoma in the Basset Hound and Basset Fauve de Bretagne Breeds of Dog.

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Oliver, James A C; Forman, Oliver P; Pettitt, Louise; Mellersh, Cathryn S

2015-01-01

Mutations in ADAMTS10 (CFA20) have previously been associated with primary open angle glaucoma (POAG) in the Beagle and Norwegian Elkhound. The closely related gene, ADAMTS17, has also been associated with several different ocular phenotypes in multiple breeds of dog, including primary lens luxation and POAG. We investigated ADAMTS17 as a candidate gene for POAG in the Basset Hound and Basset Fauve de Bretagne dog breeds. We performed ADAMTS17 exon resequencing in three Basset Hounds and three Basset Fauve de Bretagne dogs with POAG. Identified variants were genotyped in additional sample cohorts of both breeds and dogs of other breeds to confirm their association with disease. All affected Basset Hounds were homozygous for a 19 bp deletion in exon 2 that alters the reading frame and is predicted to lead to a truncated protein. Fifty clinically unaffected Basset Hounds were genotyped for this mutation and all were either heterozygous or homozygous for the wild type allele. Genotyping of 223 Basset Hounds recruited for a different study revealed a mutation frequency of 0.081 and predicted frequency of affected dogs in the population to be 0.007. Based on the entire genotyping dataset the association statistic for the POAG-associated deletion was p = 1.26 x 10-10. All affected Basset Fauve de Bretagne dogs were homozygous for a missense mutation in exon 11 causing a glycine to serine amino acid substitution (G519S) in the disintegrin-like domain of ADAMTS17 which is predicted to alter protein function. Unaffected Basset Fauve de Bretagne dogs were either heterozygous for the mutation (5/24) or homozygous for the wild type allele (19/24). Based on the entire genotyping dataset the association statistic for the POAG-associated deletion was p = 2.80 x 10-7. Genotyping of 85 dogs of unrelated breeds and 90 dogs of related breeds for this variant was negative. This report documents strong associations between two independent ADAMTS17 mutations and POAG in two different

RB1 mutation spectrum in a comprehensive nationwide cohort of retinoblastoma patients

NARCIS (Netherlands)

Dommering, Charlotte J.; Mol, Berber M.; Moll, Annette C.; Burton, Margaret; Cloos, Jacqueline; Dorsman, Josephine C.; Meijers-Heijboer, Hanne; van der Hout, Annemarie H.

Background Retinoblastoma (Rb) is a childhood cancer of the retina, commonly initiated by biallelic inactivation of the RB1 gene. Knowledge of the presence of a heritable RB1 mutation can help in risk management and reproductive decision making. We report here on RB1 mutation scanning in a unique

Bi-allelic Mutations in PKD1L1 Are Associated with Laterality Defects in Humans.

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Vetrini, Francesco; D'Alessandro, Lisa C A; Akdemir, Zeynep C; Braxton, Alicia; Azamian, Mahshid S; Eldomery, Mohammad K; Miller, Kathryn; Kois, Chelsea; Sack, Virginia; Shur, Natasha; Rijhsinghani, Asha; Chandarana, Jignesh; Ding, Yan; Holtzman, Judy; Jhangiani, Shalini N; Muzny, Donna M; Gibbs, Richard A; Eng, Christine M; Hanchard, Neil A; Harel, Tamar; Rosenfeld, Jill A; Belmont, John W; Lupski, James R; Yang, Yaping

2016-10-06

Disruption of the establishment of left-right (L-R) asymmetry leads to situs anomalies ranging from situs inversus totalis (SIT) to situs ambiguus (heterotaxy). The genetic causes of laterality defects in humans are highly heterogeneous. Via whole-exome sequencing (WES), we identified homozygous mutations in PKD1L1 from three affected individuals in two unrelated families. PKD1L1 encodes a polycystin-1-like protein and its loss of function is known to cause laterality defects in mouse and medaka fish models. Family 1 had one fetus and one deceased child with heterotaxy and complex congenital heart malformations. WES identified a homozygous splicing mutation, c.6473+2_6473+3delTG, which disrupts the invariant splice donor site in intron 42, in both affected individuals. In the second family, a homozygous c.5072G>C (p.Cys1691Ser) missense mutation was detected in an individual with SIT and congenital heart disease. The p.Cys1691Ser substitution affects a highly conserved cysteine residue and is predicted by molecular modeling to disrupt a disulfide bridge essential for the proper folding of the G protein-coupled receptor proteolytic site (GPS) motif. Damaging effects associated with substitutions of this conserved cysteine residue in the GPS motif have also been reported in other genes, namely GPR56, BAI3, and PKD1 in human and lat-1 in C. elegans, further supporting the likely pathogenicity of p.Cys1691Ser in PKD1L1. The identification of bi-allelic PKD1L1 mutations recapitulates previous findings regarding phenotypic consequences of loss of function of the orthologous genes in mice and medaka fish and further expands our understanding of genetic contributions to laterality defects in humans. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Relative autonomy of manifestation of welt mutation in imaginal discs of Drosophila

International Nuclear Information System (INIS)

Vikulova, V.K.

1988-01-01

Autonomy of manifestation of the temperature-sensitive lethal welt mutation was investigated during transplantation of imaginal discs of mutant larvae into normal recipients and in large clones of cells homozygous for welt induced by γ-irradiation in a dose of 1000 rd in y; fj wt/M(2)S7 T(1;2)sc s 2 heterozygotes. Three temperature regimes were used: 17 degree C, at which the welt mutation is not manifested; 29 degree C, at which it is manifested better; and 25 degree C. It was established that the welt mutation operates autonomously, but in restricted regions of imaginal discs. The possibility is discussed of nonautonomous manifestation of the mutation with direct contact of wt/wt cells with heteroxygous wt/+ tissue

Severe Hyperammonemic Encephalopathy Requiring Dialysis Aggravated by Prolonged Fasting and Intermittent High Fat Load in a Ramadan Fasting Month in a Patient with CPTII Homozygous Mutation.

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Phowthongkum, P; Ittiwut, C; Shotelersuk, V

2017-11-21

Carnitine palmitoyltransferase II (CPTII) deficiency is a mitochondrial fatty acid oxidation disorder that can present antenatally as congenital brain malformations, or postnatally with lethal neonatal, severe infantile, or the most common adult myopathic forms. No case of severe hyperammonemia without liver dysfunction has been reported. We described a 23-year-old man who presented to the emergency department with seizures and was found to have markedly elevation of serum ammonia. Continuous renal replacement therapy was initiated with successfully decreased ammonia to a safety level. He had a prolonged history of epilepsies and encephalopathic attacks that was associated with high ammonia level. Molecular diagnosis revealed a homozygous mutation in CPTII. The plasma acylcarnitine profile was consistent with the diagnosis. Failure to produce acetyl-CoA, the precursor of urea cycle from fatty acid in prolonged fasting state in Ramadan month, worsening mitochondrial functions from circulating long chain fatty acid and valproate toxicities were believed to contribute to this critical metabolic decompensation. Fatty acid oxidation disorders should be considered in the differential diagnosis of hyperammonemia even without liver dysfunction. To our knowledge, this is the first case of CPTII deficiency presented with severe hyperammonemic encephalopathy required dialysis after prolonged religious related fasting.

A Novel Missense Mutation in SLC5A5 Gene in a Sudanese Family with Congenital Hypothyroidism.

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Watanabe, Yui; Ebrhim, Reham Shareef; Abdullah, Mohamed A; Weiss, Roy E

2018-05-15

Thyroid hormone synthesis requires the presence of iodide. The sodium iodide symporter (NIS) is a glycoprotein which mediates the active uptake of iodide from the blood stream into the thyroid grand. NIS defects due to SLC5A5 gene mutations are known to cause congenital hypothyroidism (CH). The proposita is a 28-year-old female whose origin is the North Sudan where neonatal screening for CH is not available. She presented with severe constipation and a goiter at the age of 40 days. Laboratory testing confirmed CH and she was started on levothyroxine (L-T4). Presumably due to the delayed treatment the patient developed mental retardation. Her younger sister presented with a goiter, tongue protrusion and umbilical hernia and the youngest brother was also diagnosed with CH based on the TSH >100 µIU/mL at the age of 22 days and 8 days, respectively. Two siblings were treated with L-T4 and had normal development. Their consanguineous parents had no history of thyroid disorders. We performed whole exome sequencing (WES) on the proposita. WES identified a novel homozygous missense mutation in the SLC5A5 gene: c.1042T>G, p.Tyr348Asp, which was subsequently confirmed by Sanger sequencing. All affected children were homozygous for the same mutation and their unaffected mother was heterozygous. The NIS protein is composed of 13 transmembrane segments (TMS), an extracellular amino-terminus and an intracellular carboxyl terminus. The mutation is located in the TMS IX which has the most β-OH group-containing amino acids (serine and threonine) which is implicated in Na+ binding and translocation. In conclusion, a novel homozygous missense mutation in the SLC5A5 gene was identified in the Sudanese family with CH. The mutation is located in the TMS IX of the NIS protein which is essential for NIS function. Low iodine intake in Sudan is considered to affect severity of hypothyroidism in the patients.

Collagen XVIII Mutation in Knobloch Syndrome with Acute Lymphoblastic Leukemia

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Mahajan, Vinit B.; Olney, Ann Haskins; Garrett, Penny; Chary, Ajit; Dragan, Ecaterina; Lerner, Gary; Murray, Jeffrey; Bassuk, Alexander G.

2010-01-01

Knobloch syndrome (KNO) is caused by mutations in the collagen XIII gene (COL18A1) and patients develop encephalocele and vitreoretinal degeneration. Here we report an El Salvadorian family where two sisters showed features of KNO. One of the siblings also developed acute lymphoblastic leukemia. DNA sequencing of COL18A1revealed a homozygous, 2-base pair deletion (c3514-3515delCT) in exon 41, which leads to abnormal collagen XVIII and deficiency of its proteolytic cleavage product endostatin. KNO patients with mutations in COL18A1 may be at risk for endostatin-related conditions including malignancy. PMID:20799329

Hereditary sensory and autonomic neuropathy type IID caused by an SCN9A mutation.

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Yuan, Junhui; Matsuura, Eiji; Higuchi, Yujiro; Hashiguchi, Akihiro; Nakamura, Tomonori; Nozuma, Satoshi; Sakiyama, Yusuke; Yoshimura, Akiko; Izumo, Shuji; Takashima, Hiroshi

2013-04-30

To identify the clinical features of Japanese patients with suspected hereditary sensory and autonomic neuropathy (HSAN) on the basis of genetic diagnoses. On the basis of clinical, in vivo electrophysiologic, and pathologic findings, 9 Japanese patients with sensory and autonomic nervous dysfunctions were selected. Eleven known HSAN disease-causing genes and 5 related genes were screened using a next-generation sequencer. A homozygous mutation, c.3993delGinsTT, was identified in exon 22 of SCN9A from 2 patients/families. The clinical phenotype was characterized by adolescent or congenital onset with loss of pain and temperature sensation, autonomic nervous dysfunctions, hearing loss, and hyposmia. Subsequently, this mutation was discovered in one of patient 1's sisters, who also exhibited sensory and autonomic nervous system dysfunctions, with recurrent fractures being the most predominant feature. Nerve conduction studies revealed definite asymmetric sensory nerve involvement in patient 1. In addition, sural nerve pathologic findings showed loss of large myelinated fibers in patient 1, whereas the younger patient showed normal sural nerve pathology. We identified a novel homozygous mutation in SCN9A from 2 Japanese families with autosomal recessive HSAN. This loss-of-function SCN9A mutation results in disturbances in the sensory, olfactory, and autonomic nervous systems. We propose that SCN9A mutation results in the new entity of HSAN type IID, with additional symptoms including hyposmia, hearing loss, bone dysplasia, and hypogeusia.

Reduced rates of gene loss, gene silencing, and gene mutation in Dnmt1-deficient embryonic stem cells

NARCIS (Netherlands)

Chan, M.F.; van Amerongen, R.; Nijjar, T.; Cuppen, E.; Jones, P.A.; Laird, P.W.

2001-01-01

Tumor suppressor gene inactivation is a crucial event in oncogenesis. Gene inactivation mechanisms include events resulting in loss of heterozygosity (LOH), gene mutation, and transcriptional silencing. The contribution of each of these different pathways varies among tumor suppressor genes and by

Temporal frequency of knockdown resistance mutations, F1534C and V1016G, in Aedes aegypti in Chiang Mai city, Thailand and the impact of the mutations on the efficiency of thermal fogging spray with pyrethroids.

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Plernsub, Suriya; Saingamsook, Jassada; Yanola, Jintana; Lumjuan, Nongkran; Tippawangkosol, Pongsri; Walton, Catherine; Somboon, Pradya

2016-10-01

In Thailand, control of dengue outbreaks is currently attained by the use of space sprays, particularly thermal fogging using pyrethroids, with the aim of killing infected Aedes mosquito vectors in epidemic areas. However, the principal dengue vector, Aedes aegypti, is resistant to pyrethroids conferred mainly by mutations in the voltage-gated sodium channel gene, F1534C and V1016G, termed knockdown resistance (kdr). The objectives of this study were to determine the temporal frequencies of F1534C and V1016G in Ae. aegypti populations in relation to pyrethroid resistance in Chiang Mai city, and to evaluate the impact of the mutations on the efficacy of thermal fogging with the pyrethroid deltamethrin. Larvae and pupae were collected from several areas around Chiang Mai city during 2011-2015 and reared to adulthood for bioassays for deltamethrin susceptibility. These revealed no trend of increasing deltamethrin resistance during the study period (mortality 58.0-69.5%, average 62.8%). This corresponded to no overall change in the frequencies of the C1534 allele (0.55-0.66, average 0.62) and G1016 allele (0.34-0.45, average 0.38), determined using allele specific amplification. Only three genotypes of kdr mutations were detected: C1534 homozygous (VV/CC); G1016/C1534 double heterozygous (VG/FC); and G1016 homozygous (GG/FF) indicating that the F1534C and V1016G mutations occurred on separate haplotypic backgrounds and a lack of recombination between them to date. The F1 progeny females were used to evaluate the efficacy of thermal fogging spray with Damthrin-SP(®) (deltamethrin+S-bioallethrin+piperonyl butoxide) using a caged mosquito bioassay. The thermal fogging spray killed 100% and 61.3% of caged mosquito bioassay placed indoors and outdoors, respectively. The outdoor spray had greater killing effect on C1534 homozygous and had partially effect on double heterozygous mosquitoes, but did not kill any G1016 homozygous mutants living outdoors. As this selection

Identification of a novel frameshift mutation in the ILDR1 gene in a UAE family, mutations review and phenotype genotype correlation.

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Abdelaziz Tlili

Full Text Available Autosomal recessive non-syndromic hearing loss is one of the most common monogenic diseases. It is characterized by high allelic and locus heterogeneities that make a precise diagnosis difficult. In this study, whole-exome sequencing was performed for an affected patient allowing us to identify a new frameshift mutation (c.804delG in the Immunoglobulin-Like Domain containing Receptor-1 (ILDR1 gene. Direct Sanger sequencing and segregation analysis were performed for the family pedigree. The mutation was homozygous in all affected siblings but heterozygous in the normal consanguineous parents. The present study reports a first ILDR1 gene mutation in the UAE population and confirms that the whole-exome sequencing approach is a robust tool for the diagnosis of monogenic diseases with high levels of allelic and locus heterogeneity. In addition, by reviewing all reported ILDR1 mutations, we attempt to establish a genotype phenotype correlation to explain the phenotypic variability observed at low frequencies.

High frequency of mutation G377S in Brazilian type 3 Gaucher disease patients

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R. Rozenberg

2006-09-01

Full Text Available Gaucher disease (GD, the most prevalent lysosome storage disorder, presents an autosomal recessive mode of inheritance. It is a paradigm for therapeutic intervention in medical genetics due to the existence of effective enzyme replacement therapy. We report here the analysis of GD in 262 unrelated Brazilian patients, carried out in order to establish the frequency of the most common mutations and to provide prognostic information based on genotype-phenotype correlations. Among 247 type 1 GD patients, mutation N370S was detected in 47% of all the alleles, but N370S/N370S homozygosity was found in only 10% of the patients, a much lower frequency than expected, suggesting that most individuals presenting this genotype may not receive medical attention. Recombinant alleles were detected at a high frequency: 44% of the chromosomes bearing mutation L444P had other mutations derived from the pseudogene sequence, present in 25% of patients. Three neuronopathic type 2 patients were homozygous for L444P, all presenting additional mutations (E326K or recombinant alleles that probably lead to the more severe phenotypes. Six children, classified as type 1 GD patients, had a L444P/L444P genotype, showing that neuronopathic symptoms may only manifest later in life. This would indicate the need for a higher treatment dose during enzyme replacement therapy. Finally, mutation G377S was present in 4 homozygous type 1 patients and also in compound heterozygosity in 5 (42% type 3 patients. These findings indicate that G377S cannot be unambiguously classified as mild and suggest an allele-dose effect for this mutation.

The p16INK4alpha/p19ARF gene mutations are infrequent and are mutually exclusive to p53 mutations in Indian oral squamous cell carcinomas.

Science.gov (United States)

Kannan, K; Munirajan, A K; Krishnamurthy, J; Bhuvarahamurthy, V; Mohanprasad, B K; Panishankar, K H; Tsuchida, N; Shanmugam, G

2000-03-01

Eighty-seven untreated primary oral squamous cell carcinomas (SCCs) associated with betel quid and tobacco chewing from Indian patients were analysed for the presence of mutations in the commonly shared exon 2 of p16INK4alpha/p19ARF genes. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and sequencing analysis were used to detect mutations. SSCP analysis indicated that only 9% (8/87) of the tumours had mutation in p16INK4alpha/p19ARF genes. Seventy-two tumours studied here were previously analysed for p53 mutations and 21% (15/72) of them were found to have mutations in p53 gene. Only one tumour was found to have mutation at both p53 and p16INK4alpha/p19ARF genes. Thus, the mutation rates observed were 21% for p53, 9% for p16INK4alpha/p19ARF, and 1% for both. Sequencing analysis revealed two types of mutations; i) G to C (GCAG to CCAG) transversion type mutation at intron 1-exon 2 splice junction and ii) another C to T transition type mutation resulting in CGA to TGA changing arginine to a termination codon at p16INK4alpha gene codon 80 and the same mutation will alter codon 94 of p19ARF gene from CCG to CTG (proline to leucine). These results suggest that p16INK4alpha/p19ARF mutations are less frequent than p53 mutations in Indian oral SCCs. The p53 and p16INK4alpha/p19ARF mutational events are independent and are mutually exclusive suggesting that mutational inactivation of either p53 or p16INK4alpha/p19ARF may alleviate the need for the inactivation of the other gene.

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.

Presence of calreticulin mutations in JAK2-negative polycythemia vera.

Science.gov (United States)

Broséus, Julien; Park, Ji-Hye; Carillo, Serge; Hermouet, Sylvie; Girodon, François

2014-12-18

Calreticulin (CALR) mutations have been reported in Janus kinase 2 (JAK2)- and myeloproliferative leukemia (MPL)-negative essential thrombocythemia and primary myelofibrosis. In contrast, no CALR mutations have ever been reported in the context of polycythemia vera (PV). Here, we describe 2 JAK2(V617F)-JAK2(exon12)-negative PV patients who presented with a CALR mutation in peripheral granulocytes at the time of diagnosis. In both cases, the CALR mutation was a 52-bp deletion. Single burst-forming units-erythroid (BFU-E) from 1 patient were grown in vitro and genotyped: the same CALR del 52-bp mutation was noted in 31 of the 37 colonies examined; 30 of 31 BFU-E were heterozygous for CALR del 52 bp, and 1 of 31 BFU-E was homozygous for CALR del 52 bp. In summary, although unknown mutations leading to PV cannot be ruled out, our results suggest that CALR mutations can be associated with JAK2-negative PV. © 2014 by The American Society of Hematology.

Genetic characterization in symptomatic female DMD carriers: lack of relationship between X-inactivation, transcriptional DMD allele balancing and phenotype

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Brioschi Simona

2012-08-01

Full Text Available Abstract Background Although Duchenne and Becker muscular dystrophies, X-linked recessive myopathies, predominantly affect males, a clinically significant proportion of females manifesting symptoms have also been reported. They represent an heterogeneous group characterized by variable degrees of muscle weakness and/or cardiac involvement. Though preferential inactivation of the normal X chromosome has long been considered the principal mechanism behind disease manifestation in these females, supporting evidence is controversial. Methods Eighteen females showing a mosaic pattern of dystrophin expression on muscle biopsy were recruited and classified as symptomatic (7 or asymptomatic (11, based on the presence or absence of muscle weakness. The causative DMD gene mutations were identified in all cases, and the X-inactivation pattern was assessed in muscle DNA. Transcriptional analysis in muscles was performed in all females, and relative quantification of wild-type and mutated transcripts was also performed in 9 carriers. Dystrophin protein was quantified by immunoblotting in 2 females. Results The study highlighted a lack of relationship between dystrophic phenotype and X-inactivation pattern in females; skewed X-inactivation was found in 2 out of 6 symptomatic carriers and in 5 out of 11 asymptomatic carriers. All females were characterized by biallelic transcription, but no association was found between X-inactivation pattern and allele transcriptional balancing. Either a prevalence of wild-type transcript or equal proportions of wild-type and mutated RNAs was observed in both symptomatic and asymptomatic females. Moreover, very similar levels of total and wild-type transcripts were identified in the two groups of carriers. Conclusions This is the first study deeply exploring the DMD transcriptional behaviour in a cohort of female carriers. Notably, no relationship between X-inactivation pattern and transcriptional behaviour of DMD gene was

Current Nomenclature of Pseudohypoparathyroidism: Inactivating Parathyroid Hormone/Parathyroid Hormone-Related Protein Signaling Disorder.

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Turan, Serap

2017-12-30

Disorders related to parathyroid hormone (PTH) resistance and PTH signaling pathway impairment are historically classified under the term of pseudohypoparathyroidism (PHP). The disease was first described and named by Fuller Albright and colleagues in 1942. Albright hereditary osteodystrophy (AHO) is described as an associated clinical entity with PHP, characterized by brachydactyly, subcutaneous ossifications, round face, short stature and a stocky build. The classification of PHP is further divided into PHP-Ia, pseudo-PHP (pPHP), PHP-Ib, PHP-Ic and PHP-II according to the presence or absence of AHO, together with an in vivo response to exogenous PTH and the measurement of Gsα protein activity in peripheral erythrocyte membranes in vitro. However, PHP classification fails to differentiate all patients with different clinical and molecular findings for PHP subtypes and classification become more complicated with more recent molecular characterization and new forms having been identified. So far, new classifications have been established by the EuroPHP network to cover all disorders of the PTH receptor and its signaling pathway. Inactivating PTH/PTH-related protein signaling disorder (iPPSD) is the new name proposed for a group of these disorders and which can be further divided into subtypes - iPPSD1 to iPPSD6. These are termed, starting from PTH receptor inactivation mutation (Eiken and Blomstrand dysplasia) as iPPSD1, inactivating Gsα mutations (PHP-Ia, PHP-Ic and pPHP) as iPPSD2, loss of methylation of GNAS DMRs (PHP-Ib) as iPPSD3, PRKAR1A mutations (acrodysostosis type 1) as iPPSD4, PDE4D mutations (acrodysostosis type 2) as iPPSD5 and PDE3A mutations (autosomal dominant hypertension with brachydactyly) as iPPSD6. iPPSDx is reserved for unknown molecular defects and iPPSDn+1 for new molecular defects which are yet to be described. With these new classifications, the aim is to clarify the borders of each different subtype of disease and make the classification

Constitutional Mismatch Repair Deficiency in Israel: High Proportion of Founder Mutations in MMR Genes and Consanguinity.

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Baris, Hagit N; Barnes-Kedar, Inbal; Toledano, Helen; Halpern, Marisa; Hershkovitz, Dov; Lossos, Alexander; Lerer, Israela; Peretz, Tamar; Kariv, Revital; Cohen, Shlomi; Half, Elizabeth E; Magal, Nurit; Drasinover, Valerie; Wimmer, Katharina; Goldberg, Yael; Bercovich, Dani; Levi, Zohar

2016-03-01

Heterozygous germline mutations in any of the mismatch repair (MMR) genes, MLH1, MSH2, MSH6, and PMS2, cause Lynch syndrome (LS), an autosomal dominant cancer predisposition syndrome conferring a high risk of colorectal, endometrial, and other cancers in adulthood. Offspring of couples where both spouses have LS have a 1:4 risk of inheriting biallelic MMR gene mutations. These cause constitutional MMR deficiency (CMMRD) syndrome, a severe recessively inherited cancer syndrome with a broad tumor spectrum including mainly hematological malignancies, brain tumors, and colon cancer in childhood and adolescence. Many CMMRD children also present with café au lait spots and axillary freckling mimicking neurofibromatosis type 1. We describe our experience in seven CMMRD families demonstrating the role and importance of founder mutations and consanguinity on its prevalence. Clinical presentations included brain tumors, colon cancer, lymphoma, and small bowel cancer. In children from two nonconsanguineous Ashkenazi Jewish (AJ) families, the common Ashkenazi founder mutations were detected; these were homozygous in one family and compound heterozygous in the other. In four consanguineous families of various ancestries, different homozygous mutations were identified. In a nonconsanguineous Caucasus/AJ family, lack of PMS2 was demonstrated in tumor and normal tissues; however, mutations were not identified. CMMRD is rare, but, especially in areas where founder mutations for LS and consanguinity are common, pediatricians should be aware of it since they are the first to encounter these children. Early diagnosis will enable tailored cancer surveillance in the entire family and a discussion regarding prenatal genetic diagnosis. © 2015 Wiley Periodicals, Inc.

Diseases associated with growth hormone-releasing hormone receptor (GHRHR) mutations.

Science.gov (United States)

Martari, Marco; Salvatori, Roberto

2009-01-01

The growth hormone (GH)-releasing hormone (GHRH) receptor (GHRHR) belongs to the G protein-coupled receptors family. It is expressed almost exclusively in the anterior pituitary, where it is necessary for somatotroph cells proliferation and for GH synthesis and secretion. Mutations in the human GHRHR gene (GHRHR) can impair ligand binding and signal transduction, and have been estimated to cause about 10% of autosomal recessive familial isolated growth hormone deficiency (IGHD). Mutations reported to date include five splice donor site mutations, two microdeletions, two nonsense mutations, seven missense mutations, and one mutation in the promoter. These mutations have an autosomal recessive mode of inheritance, and heterozygous individuals do not show signs of IGHD, although the presence of an intermediate phenotype has been hypothesized. Conversely, patients with biallelic mutations have low serum insulin-like growth factor-1 and GH levels (with absent or reduced GH response to exogenous stimuli), resulting--if not treated--in proportionate dwarfism. This chapter reviews the biology of the GHRHR, the mutations that affect its gene and their effects in homozygous and heterozygous individuals. Copyright © 2009 Elsevier Inc. All rights reserved.

A patient with common glycogen storage disease type Ib mutations without neutropenia or neutrophil dysfunction

NARCIS (Netherlands)

Martens, DHJ; Kuijpers, TW; Maianski, NA; Rake, JP; Smit, GPA; Visser, G

We describe a 16-year old boy with glycogen storage disease type Ib, homozygous for the common 1211-1212delCT mutation, who never experienced neutropenia, and did not suffer from frequent infections or inflammatory bowel disease. In addition, neutrophil function tests showed no abnormalities.

Homozygous deletion of TRMT10A as part of a contiguous gene deletion in a syndrome of failure to thrive, delayed puberty, intellectual disability and diabetes mellitus.

Science.gov (United States)

Zung, Amnon; Kori, Michal; Burundukov, Ella; Ben-Yosef, Tamar; Tatoor, Yasmin; Granot, Esther

2015-12-01

Two recent reports describe a new syndrome of intellectual disability, short stature, microcephaly, and young onset diabetes or disturbed glucose metabolism in association with inactivating mutations in the TRMT10A gene. We investigated the clinical spectrum presented by a 17-year-old female with a homozygous contiguous gene deletion involving the TRMT10A gene. From infancy, she presented with failure to thrive and microcephaly. Puberty was characterized by a slow and an inconsistent course of progression. Concomitantly, gonadotropin levels fluctuated between low and high levels which were compatible with gonadal failure. Unlike the previous reports, the patient had ketoacidosis at onset of diabetes and islet cell autoantibodies. Nevertheless, glycemic control was excellent (HbA1C 5.0%-6.2%). RT-PCR and Western blot analysis demonstrated a complete abolishment of TRMT10A mRNA and its translated protein. In order to elucidate the nature of diabetes in this patient, endogenous insulin secretion and glycemic control were evaluated by a glucagon stimulation test and continuous glucose monitoring both during insulin treatment and off therapy. Endogenous insulin secretion still persisted 22 months after onset of diabetes and relatively normal glucose levels were kept over 3 days without insulin treatment. The fluctuating course of puberty and diabetes may reflect intermittent apoptotic damages due to sensitization of the relevant cells to various stress agents in the absence of functional TRMT10A. © 2015 Wiley Periodicals, Inc.

Distinct pattern of p53 mutations in bladder cancer

DEFF Research Database (Denmark)

Spruck, C H; Rideout, W M; Olumi, A F

1993-01-01

A distinct mutational spectrum for the p53 tumor suppressor gene in bladder carcinomas was established in patients with known exposures to cigarette smoke. Single-strand conformational polymorphism analysis of exons 5 through 8 of the p53 gene showed inactivating mutations in 16 of 40 (40%) bladder...... tumors from smokers and 13 of 40 (33%) tumors from lifetime nonsmokers. Overall, 13 of the 50 (26%) total point mutations discovered in this and previous work were G:C-->C:G transversions, a relatively rare mutational type in human tumors. In six tumors, identical AGA (Arg)-->ACA (Thr) point mutations...... double mutations, four of which were tandem mutations on the same allele. No double mutations were found in tumors from nonsmoking patients. None of the mutations in smokers were G:C-->T:A transversions, which would be anticipated for exposure to the suspected cigarette smoke carcinogen 4-aminobiphenyl...

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

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Kairong Li

2016-07-01

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

The FTD-like syndrome causing TREM2 T66M mutation impairs microglia function, brain perfusion, and glucose metabolism.

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Kleinberger, Gernot; Brendel, Matthias; Mracsko, Eva; Wefers, Benedikt; Groeneweg, Linda; Xiang, Xianyuan; Focke, Carola; Deußing, Maximilian; Suárez-Calvet, Marc; Mazaheri, Fargol; Parhizkar, Samira; Pettkus, Nadine; Wurst, Wolfgang; Feederle, Regina; Bartenstein, Peter; Mueggler, Thomas; Arzberger, Thomas; Knuesel, Irene; Rominger, Axel; Haass, Christian

2017-07-03

Genetic variants in the triggering receptor expressed on myeloid cells 2 (TREM2) increase the risk for several neurodegenerative diseases including Alzheimer's disease and frontotemporal dementia (FTD). Homozygous TREM2 missense mutations, such as p.T66M, lead to the FTD-like syndrome, but how they cause pathology is unknown. Using CRISPR/Cas9 genome editing, we generated a knock-in mouse model for the disease-associated Trem2 p.T66M mutation. Consistent with a loss-of-function mutation, we observe an intracellular accumulation of immature mutant Trem2 and reduced generation of soluble Trem2 similar to patients with the homozygous p.T66M mutation. Trem2 p.T66M knock-in mice show delayed resolution of inflammation upon in vivo lipopolysaccharide stimulation and cultured macrophages display significantly reduced phagocytic activity. Immunohistochemistry together with in vivo TSPO small animal positron emission tomography (μPET) demonstrates an age-dependent reduction in microglial activity. Surprisingly, perfusion magnetic resonance imaging and FDG-μPET imaging reveal a significant reduction in cerebral blood flow and brain glucose metabolism. Thus, we demonstrate that a TREM2 loss-of-function mutation causes brain-wide metabolic alterations pointing toward a possible function of microglia in regulating brain glucose metabolism. © 2017 The Authors.

Inactivation of Caliciviruses

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Raymond Nims

2013-03-01

Full Text Available The Caliciviridae family of viruses contains clinically important human and animal pathogens, as well as vesivirus 2117, a known contaminant of biopharmaceutical manufacturing processes employing Chinese hamster cells. An extensive literature exists for inactivation of various animal caliciviruses, especially feline calicivirus and murine norovirus. The caliciviruses are susceptible to wet heat inactivation at temperatures in excess of 60 °C with contact times of 30 min or greater, to UV-C inactivation at fluence ≥30 mJ/cm2, to high pressure processing >200 MPa for >5 min at 4 °C, and to certain photodynamic inactivation approaches. The enteric caliciviruses (e.g.; noroviruses display resistance to inactivation by low pH, while the non-enteric species (e.g.; feline calicivirus are much more susceptible. The caliciviruses are inactivated by a variety of chemicals, including alcohols, oxidizing agents, aldehydes, and β-propiolactone. As with inactivation of viruses in general, inactivation of caliciviruses by the various approaches may be matrix-, temperature-, and/or contact time-dependent. The susceptibilities of the caliciviruses to the various physical and chemical inactivation approaches are generally similar to those displayed by other small, non-enveloped viruses, with the exception that the parvoviruses and circoviruses may require higher temperatures for inactivation, while these families appear to be more susceptible to UV-C inactivation than are the caliciviruses.

Novel mutations in Norrie disease gene in Japanese patients with Norrie disease and familial exudative vitreoretinopathy.

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Kondo, Hiroyuki; Qin, Minghui; Kusaka, Shunji; Tahira, Tomoko; Hasebe, Haruyuki; Hayashi, Hideyuki; Uchio, Eiichi; Hayashi, Kenshi

2007-03-01

To search for mutations in the Norrie disease gene (NDP) in Japanese patients with familial exudative vitreoretinopathy (FEVR) and Norrie disease (ND) and to delineate the mutation-associated clinical features. Direct sequencing after polymerase chain reaction of all exons of the NDP gene was performed on blood collected from 62 probands (31 familial and 31 simplex) with FEVR, from 3 probands with ND, and from some of their family members. The clinical symptoms and signs in the patients with mutations were assessed. X-inactivation in the female carriers was examined in three FEVR families by using leukocyte DNA. Four novel mutations-I18K, K54N, R115L, and IVS2-1G-->A-and one reported mutation, R97P, in the NDP gene were identified in six families. The severity of vitreoretinopathy varied among these patients. Three probands with either K54N or R115L had typical features of FEVR, whereas the proband with R97P had those of ND. Families with IVS2-1G-->A exhibited either ND or FEVR characteristics. A proband with I18K presented with significant phenotypic heterogeneity between the two eyes. In addition, affected female carriers in a family harboring the K54N mutation presented with different degrees of vascular abnormalities in the periphery of the retina. X-inactivation profiles indicated that the skewing was not significantly different between affected and unaffected women. These observations indicate that mutations of the NDP gene can cause ND and 6% of FEVR cases in the Japanese population. The X-inactivation assay with leukocytes may not be predictive of the presence of a mutation in affected female carriers.

Novel LMF1 Nonsense Mutation in a Patient with Severe Hypertriglyceridemia

OpenAIRE

Cefalù, Angelo B.; Noto, Davide; Arpi, Maria Luisa; Yin, Fen; Spina, Rossella; Hilden, Hannele; Barbagallo, Carlo M.; Carroccio, Antonio; Tarugi, Patrizia; Squatrito, Sebastiano; Vigneri, Riccardo; Taskinen, Marja-Riitta; Péterfy, Miklós; Averna, Maurizio R.

2009-01-01

Context: Lipase maturation factor 1 (LMF1) gene is a novel candidate gene in severe hypertriglyceridemia. Lmf1 is involved in the maturation of lipoprotein lipase (LPL) and hepatic lipase in endoplasmic reticulum. To date only one patient with severe hypertriglyceridemia and related disorders was found to be homozygous for a nonsense mutation in LMF1 gene (Y439X).

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.

Functional characterization of a new p53 mutant generated by homozygous deletion in a neuroblastoma cell line

International Nuclear Information System (INIS)

Nakamura, Yohko; Ozaki, Toshinori; Niizuma, Hidetaka; Ohira, Miki; Kamijo, Takehiko; Nakagawara, Akira

2007-01-01

p53 is a key modulator of a variety of cellular stresses. In human neuroblastomas, p53 is rarely mutated and aberrantly expressed in cytoplasm. In this study, we have identified a novel p53 mutant lacking its COOH-terminal region in neuroblastoma SK-N-AS cells. p53 accumulated in response to cisplatin (CDDP) and thereby promoting apoptosis in neuroblastoma SH-SY5Y cells bearing wild-type p53, whereas SK-N-AS cells did not undergo apoptosis. We found another p53 (p53ΔC) lacking a part of oligomerization domain and nuclear localization signals in SK-N-AS cells. p53ΔC was expressed largely in cytoplasm and lost the transactivation function. Furthermore, a 3'-part of the p53 locus was homozygously deleted in SK-N-AS cells. Thus, our present findings suggest that p53 plays an important role in the DNA-damage response in certain neuroblastoma cells and it seems to be important to search for p53 mutations outside DNA-binding domain

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

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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.

Novel Founder Mutation in FANCA Gene (c.3446_3449dupCCCT) Among Romani Patients from the Balkan Region

OpenAIRE

Marija Dimishkovska; Vjosa Mulliqi Kotori; Zoran Gucev; Svetlana Kocheva; Momir Polenakovic; Dijana Plaseska-Karanfilska

2018-01-01

Background: Fanconi anemia is a rare autosomal recessive or X-linked disorder characterised by clinical and genetic heterogeneity. Most fanconi anemia patients harbour homozygous or double heterozygous mutations in the FANCA (60-65%), FANCC (10-15%), FANCG (~10%) or FANCD2 (3-6%) genes. We have already reported the FANCA variant c.190–256_283+1680del2040dupC as a founder mutation among Macedonian fanconi anemia patients of Gypsy-like ethnic origin. Here, we present a novel FANCA mutation in t...

The SHOX region and its mutations.

Science.gov (United States)

Capone, L; Iughetti, L; Sabatini, S; Bacciaglia, A; Forabosco, A

2010-06-01

The short stature homeobox-containing (SHOX) gene lies in the pseudoautosomal region 1 (PAR1) that comprises 2.6 Mb of the short-arm tips of both the X and Y chromosomes. It is known that its heterozygous mutations cause Leri-Weill dyschondrosteosis (LWD) (OMIM #127300), while its homozygous mutations cause a severe form of dwarfism known as Langer mesomelic dysplasia (LMD) (OMIM #249700). The analysis of 238 LWD patients between 1998 and 2007 by multiple authors shows a prevalence of deletions (46.4%) compared to point mutations (21.2%). On the whole, deletions and point mutations account for about 67% of LWD patients. SHOX is located within a 1000 kb desert region without genes. The comparative genomic analysis of this region between genomes of different vertebrates has led to the identification of evolutionarily conserved non-coding DNA elements (CNE). Further functional studies have shown that one of these CNE downstream of the SHOX gene is necessary for the expression of SHOX; this is considered to be typical "enhancer" activity. Including the enhancer, the overall mutation of the SHOX region in LWD patients does not hold in 100% of cases. Various authors have demonstrated the existence of other CNE both downstream and upstream of SHOX regions. The resulting conclusion is that it is necessary to reanalyze all LWD/LMD patients without SHOX mutations for the presence of mutations in the 5'- and 3'-flanking SHOX regions.

TREM2 mutations are rare in a French cohort of patients with frontotemporal dementia.

Science.gov (United States)

Lattante, Serena; Le Ber, Isabelle; Camuzat, Agnès; Dayan, Sarah; Godard, Chloé; Van Bortel, Inge; De Septenville, Anne; Ciura, Sorana; Brice, Alexis; Kabashi, Edor

2013-10-01

Homozygous mutations in TREM2 have been recently identified by exome sequencing in families presenting with frontotemporal dementia (FTD)-like phenotype. No study has evaluated the exact frequency of TREM2 mutations in cohorts of FTD patients so far. We sequenced TREM2 in 175 patients with pure FTD, mostly French, to test whether mutations could be implicated in the pathogenesis of the disease. No disease-causing mutation was identified in 175 individuals from the French cohort of FTD patients. We did not identify the polymorphism p.R47H (rs75932628), strongly associated with an increased risk of developing Alzheimer's disease. We conclude that TREM2 mutations are extremely rare in patients with pure FTD, although further investigation in larger populations is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

Dysmorphic Facial Features and Other Clinical Characteristics in Two Patients with PEX1 Gene Mutations

Science.gov (United States)

Gunduz, Mehmet

2016-01-01

Peroxisomal disorders are a group of genetically heterogeneous metabolic diseases related to dysfunction of peroxisomes. Dysmorphic features, neurological abnormalities, and hepatic dysfunction can be presenting signs of peroxisomal disorders. Here we presented dysmorphic facial features and other clinical characteristics in two patients with PEX1 gene mutation. Follow-up periods were 3.5 years and 1 year in the patients. Case I was one-year-old girl that presented with neurodevelopmental delay, hepatomegaly, bilateral hearing loss, and visual problems. Ophthalmologic examination suggested septooptic dysplasia. Cranial magnetic resonance imaging (MRI) showed nonspecific gliosis at subcortical and periventricular deep white matter. Case II was 2.5-year-old girl referred for investigation of global developmental delay and elevated liver enzymes. Ophthalmologic examination findings were consistent with bilateral nystagmus and retinitis pigmentosa. Cranial MRI was normal. Dysmorphic facial features including broad nasal root, low set ears, downward slanting eyes, downward slanting eyebrows, and epichantal folds were common findings in two patients. Molecular genetic analysis indicated homozygous novel IVS1-2A>G mutation in Case I and homozygous p.G843D (c.2528G>A) mutation in Case II in the PEX1 gene. Clinical findings and developmental prognosis vary in PEX1 gene mutation. Kabuki-like phenotype associated with liver pathology may indicate Zellweger spectrum disorders (ZSD). PMID:27882258

Independent inactivation of arginine decarboxylase genes by nonsense and missense mutations led to pseudogene formation in Chlamydia trachomatis serovar L2 and D strains

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Graham David E

2009-07-01

Full Text Available Abstract Background Chlamydia have reduced genomes that reflect their obligately parasitic lifestyle. Despite their different tissue tropisms, chlamydial strains share a large number of common genes and have few recognized pseudogenes, indicating genomic stability. All of the Chlamydiaceae have homologs of the aaxABC gene cluster that encodes a functional arginine:agmatine exchange system in Chlamydia (Chlamydophilapneumoniae. However, Chlamydia trachomatis serovar L2 strains have a nonsense mutation in their aaxB genes, and C. trachomatis serovar A and B strains have frameshift mutations in their aaxC homologs, suggesting that relaxed selection may have enabled the evolution of aax pseudogenes. Biochemical experiments were performed to determine whether the aaxABC genes from C. trachomatis strains were transcribed, and mutagenesis was used to identify nucleotide substitutions that prevent protein maturation and activity. Molecular evolution techniques were applied to determine the relaxation of selection and the scope of aax gene inactivation in the Chlamydiales. Results The aaxABC genes were co-transcribed in C. trachomatis L2/434, during the mid-late stage of cellular infection. However, a stop codon in the aaxB gene from this strain prevented the heterologous production of an active pyruvoyl-dependent arginine decarboxylase. Replacing that ochre codon with its ancestral tryptophan codon rescued the activity of this self-cleaving enzyme. The aaxB gene from C. trachomatis D/UW-3 was heterologously expressed as a proenzyme that failed to cleave and form the catalytic pyruvoyl cofactor. This inactive protein could be rescued by replacing the arginine-115 codon with an ancestral glycine codon. The aaxC gene from the D/UW-3 strain encoded an active arginine:agmatine antiporter protein, while the L2/434 homolog was unexpectedly inactive. Yet the frequencies of nonsynonymous versus synonymous nucleotide substitutions show no signs of relaxed

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

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Caitlin J Rinz

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

Premature Valvular Heart Disease in Homozygous Familial Hypercholesterolemia.

Science.gov (United States)

Fahed, Akl C; Shibbani, Kamel; Andary, Rabih R; Arabi, Mariam T; Habib, Robert H; Nguyen, Denis D; Haddad, Fady F; Moubarak, Elie; Nemer, Georges; Azar, Sami T; Bitar, Fadi F

2017-01-01

Valvular heart disease frequently occurs as a consequence of premature atherosclerosis in individuals with familial hypercholesterolemia (FH). Studies have primarily focused on aortic valve calcification in heterozygous FH, but there is paucity of data on the incidence of valvular disease in homozygous FH. We performed echocardiographic studies in 33 relatively young patients (mean age: 26 years) with homozygous FH (mean LDL of 447 mg/dL, 73% on LDL apheresis) to look for subclinical valvulopathy. Twenty-one patients had evidence of valvulopathy of the aortic or mitral valves, while seven subjects showed notable mitral regurgitation. Older patients were more likely to have aortic valve calcification (>21 versus ≤21 years: 59% versus 12.5%; p = 0.01) despite lower LDL levels at the time of the study (385 versus 513 mg/dL; p = 0.016). Patients with valvulopathy were older and had comparable LDL levels and a lower carotid intima-media thickness. Our data suggests that, in homozygous FH patients, valvulopathy (1) is present across a wide age spectrum and LDL levels and (2) is less likely to be influenced by lipid-lowering treatment. Echocardiographic studies that focused on aortic root thickening and stenosis and regurgitation are thus likely an effective modality for serial follow-up of subclinical valvular heart disease.

Surfactant protein B deficiency and gene mutations for neonatal respiratory distress syndrome in China Han ethnic population

Science.gov (United States)

Yin, Xiaojuan; Meng, Fanping; wang, Yan; Xie, Lu; Kong, Xiangyong; Feng, Zhichun

2013-01-01

Objective: To determine whether the SP-B deficiency and gene mutations in exon 4 is associated with neonatal RDS in China Han ethnic population. Methods: The study population consisted of 40 neonates with RDS and 40 neonates with other diseases as control in China Han ethnic population. We Compared SP-B expression in lung tissue and bronchoalveolar lavage fluid with immunoblotting, and analyzed mutations in the SP-B gene with polymerase chain reaction (PCR) and gene sequencing. Results: In RDS group, low mature Surfactant protein B was found in both lung tissue and bronchoalveolar lavage fluid in 8 neonates. In control group, only 4 neonates with low mature Surfactant protein B in both lung tissue and bronchoalveolar lavage fluid. In RDS group, 20 neonates were found to have mutations in exon 4, 12 homozygous mutations with C/C genotype and 8 heterozygous mutations with C/T genotype in surfactant protein B gene+1580 polymorphism. There were 8 cases mutations in control group, 1 in C/C and 7 in C/T genotype. The frequency of homozygotes with C/C genotype was 0.3 and frequency of heterozygotes with C/T genotype was 0.02 in RDS group. In control group, frequency of homozygotes with C/C genotype was 0.025 and frequency of heterozygote with C/T genotype was 0.175. Conclusion: Low mature Surfactant protein B is associated with the pathogenesis of neonatal respiratory distress syndrome (RDS) in China Han ethnic population. Mutations in exon 4 of the surfactant protein B gene demonstrate an association between homozygous mutations with C/C genotype in SP-B gene and neonatal RDS. PMID:23330012

Medium-chain acyl-CoA dehydrogenase (MCAD) mutations identified by MS/MS-based prospective screening of newborns differ from those observed in patients with clinical symptoms

DEFF Research Database (Denmark)

Andresen, B S; Dobrowolski, S F; O'Reilly, L

2001-01-01

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most frequently diagnosed mitochondrial beta-oxidation defect, and it is potentially fatal. Eighty percent of patients are homozygous for a common mutation, 985A-->G, and a further 18% have this mutation in only one disease allele. In a...

Detection of the V1016G mutation in the voltage-gated sodium channel gene of Aedes aegypti (Diptera: Culicidae) by allele-specific PCR assay, and its distribution and effect on deltamethrin resistance in Thailand.

Science.gov (United States)

Stenhouse, Steven A; Plernsub, Suriya; Yanola, Jintana; Lumjuan, Nongkran; Dantrakool, Anchalee; Choochote, Wej; Somboon, Pradya

2013-08-30

Resistance to pyrethroid insecticides is widespread among populations of Aedes aegypti, the main vector for the dengue virus. Several different point mutations within the voltage-gated sodium channel (VGSC) gene contribute to such resistance. A mutation at position 1016 in domain II, segment 6 of the VGSC gene in Ae. aegypti leads to a valine to glycine substitution (V1016G) that confers resistance to deltamethrin. This study developed and utilized an allele-specific PCR (AS-PCR) assay that could be used to detect the V1016G mutation. The assay was validated against a number of sequenced DNA samples of known genotype and was determined to be in complete agreement. Larvae and pupae were collected from various localities throughout Thailand. Samples were reared to adulthood and their resistance status against deltamethrin was determined by standard WHO susceptibility bioassays. Deltamethrin-resistant and susceptible insects were then genotyped for the V1016G mutation. Additionally, some samples were genotyped for a second mutation at position 1534 in domain III (F1534C) which is also known to confer pyrethroid resistance. The bioassay results revealed an overall mortality of 77.6%. Homozygous 1016G individuals survived at higher rates than either heterozygous or wild-type (1016 V) mosquitoes. The 1016G mutation was significantly and positively associated with deltamethrin resistance and was widely distributed throughout Thailand. Interestingly, wild-type 1016 V mosquitoes tested were homozygous for the 1534C mutation, and all heterozygous mosquitoes were also heterozygous for 1534C. Mutant homozygous (G/G) mosquitoes expressed the wild-type (F/F) at position 1534. However, the presence of the 1534C mutation was not associated with deltamethrin resistance. Our bioassay results indicate that all populations sampled display some degree of resistance to deltamethrin. Homozygous 1016G mosquitoes were far likelier to survive such exposure. However, resistance in some

Catalytically Active Guanylyl Cyclase B Requires Endoplasmic Reticulum-mediated Glycosylation, and Mutations That Inhibit This Process Cause Dwarfism.

Science.gov (United States)

Dickey, Deborah M; Edmund, Aaron B; Otto, Neil M; Chaffee, Thomas S; Robinson, Jerid W; Potter, Lincoln R

2016-05-20

C-type natriuretic peptide activation of guanylyl cyclase B (GC-B), also known as natriuretic peptide receptor B or NPR2, stimulates long bone growth, and missense mutations in GC-B cause dwarfism. Four such mutants (L658F, Y708C, R776W, and G959A) bound (125)I-C-type natriuretic peptide on the surface of cells but failed to synthesize cGMP in membrane GC assays. Immunofluorescence microscopy also indicated that the mutant receptors were on the cell surface. All mutant proteins were dephosphorylated and incompletely glycosylated, but dephosphorylation did not explain the inactivation because the mutations inactivated a "constitutively phosphorylated" enzyme. Tunicamycin inhibition of glycosylation in the endoplasmic reticulum or mutation of the Asn-24 glycosylation site decreased GC activity, but neither inhibition of glycosylation in the Golgi by N-acetylglucosaminyltransferase I gene inactivation nor PNGase F deglycosylation of fully processed GC-B reduced GC activity. We conclude that endoplasmic reticulum-mediated glycosylation is required for the formation of an active catalytic, but not ligand-binding domain, and that mutations that inhibit this process cause dwarfism. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

The prevalence of mutations in the gene encoding filaggrin in the population of Polish patients with atopic dermatitis

Directory of Open Access Journals (Sweden)

Magdalena Woźniak

2016-05-01

Full Text Available Introduction : The genetic background of atopic dermatitis (AD is complex, involves many genes and their participation varies in varied populations, and depends on the intensity and course of a disease. Changes in the nucleotide sequence of the FLG gene and a reduced number or a deficit of the functional product of processed profilaggrin can be one of risk factors for atopic dermatitis. Aim : To determine the prevalence of R501X and 2282del4 mutations of the FLG gene in patients with AD. Material and methods : The studied group included 60 patients with clinically diagnosed AD, and the control group included 61 healthy volunteers. The study protocol included collection of biological material for tests, DNA isolation and evaluation of its quality and quantity, and PCR amplification of the isolated genetic material. Results : In the studied group, both changes in the nucleotide sequence of the FLG gene were detected and in the control group no tested mutations were detected. In 18 (30% patients with AD, 22 mutations (4 heterozygous and 1 homozygous ones of R501X and 10 heterozygous and 7 homozygous ones of 2282del4 were detected. Conclusions : A high rate of mutations of the FLG gene in patients with clinically diagnosed AD and pathologically dry skin was observed in the studied population. The 2282del4 mutation occurred more often than R501X.

Domain IV voltage-sensor movement is both sufficient and rate limiting for fast inactivation in sodium channels.

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Capes, Deborah L; Goldschen-Ohm, Marcel P; Arcisio-Miranda, Manoel; Bezanilla, Francisco; Chanda, Baron

2013-08-01

Voltage-gated sodium channels are critical for the generation and propagation of electrical signals in most excitable cells. Activation of Na(+) channels initiates an action potential, and fast inactivation facilitates repolarization of the membrane by the outward K(+) current. Fast inactivation is also the main determinant of the refractory period between successive electrical impulses. Although the voltage sensor of domain IV (DIV) has been implicated in fast inactivation, it remains unclear whether the activation of DIV alone is sufficient for fast inactivation to occur. Here, we functionally neutralize each specific voltage sensor by mutating several critical arginines in the S4 segment to glutamines. We assess the individual role of each voltage-sensing domain in the voltage dependence and kinetics of fast inactivation upon its specific inhibition. We show that movement of the DIV voltage sensor is the rate-limiting step for both development and recovery from fast inactivation. Our data suggest that activation of the DIV voltage sensor alone is sufficient for fast inactivation to occur, and that activation of DIV before channel opening is the molecular mechanism for closed-state inactivation. We propose a kinetic model of sodium channel gating that can account for our major findings over a wide voltage range by postulating that DIV movement is both necessary and sufficient for fast inactivation.

The PRRT2 knockout mouse recapitulates the neurological diseases associated with PRRT2 mutations.

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Michetti, Caterina; Castroflorio, Enrico; Marchionni, Ivan; Forte, Nicola; Sterlini, Bruno; Binda, Francesca; Fruscione, Floriana; Baldelli, Pietro; Valtorta, Flavia; Zara, Federico; Corradi, Anna; Benfenati, Fabio

2017-03-01

Heterozygous and rare homozygous mutations in PRoline-Rich Transmembrane protein 2 (PRRT2) underlie a group of paroxysmal disorders including epilepsy, kinesigenic dyskinesia episodic ataxia and migraine. Most of the mutations lead to impaired PRRT2 expression and/or function. Recently, an important role for PRTT2 in the neurotransmitter release machinery, brain development and synapse formation has been uncovered. In this work, we have characterized the phenotype of a mouse in which the PRRT2 gene has been constitutively inactivated (PRRT2 KO). β-galactosidase staining allowed to map the regional expression of PRRT2 that was more intense in the cerebellum, hindbrain and spinal cord, while it was localized to restricted areas in the forebrain. PRRT2 KO mice are normal at birth, but display paroxysmal movements at the onset of locomotion that persist in the adulthood. In addition, adult PRRT2 KO mice present abnormal motor behaviors characterized by wild running and jumping in response to audiogenic stimuli that are ineffective in wild type mice and an increased sensitivity to the convulsive effects of pentylentetrazol. Patch-clamp electrophysiology in hippocampal and cerebellar slices revealed specific effects in the cerebellum, where PRRT2 is highly expressed, consisting in a higher excitatory strength at parallel fiber-Purkinje cell synapses during high frequency stimulation. The results show that the PRRT2 KO mouse reproduces the motor paroxysms present in the human PRRT2-linked pathology and can be proposed as an experimental model for the study of the pathogenesis of the disease as well as for testing personalized therapeutic approaches. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Biallelic UFM1 and UFC1 mutations expand the essential role of ufmylation in brain development.

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Nahorski, Michael S; Maddirevula, Sateesh; Ishimura, Ryosuke; Alsahli, Saud; Brady, Angela F; Begemann, Anaïs; Mizushima, Tsunehiro; Guzmán-Vega, Francisco J; Obata, Miki; Ichimura, Yoshinobu; Alsaif, Hessa S; Anazi, Shams; Ibrahim, Niema; Abdulwahab, Firdous; Hashem, Mais; Monies, Dorota; Abouelhoda, Mohamed; Meyer, Brian F; Alfadhel, Majid; Eyaid, Wafa; Zweier, Markus; Steindl, Katharina; Rauch, Anita; Arold, Stefan T; Woods, C Geoffrey; Komatsu, Masaaki; Alkuraya, Fowzan S

2018-06-02

The post-translational modification of proteins through the addition of UFM1, also known as ufmylation, plays a critical developmental role as revealed by studies in animal models. The recent finding that biallelic mutations in UBA5 (the E1-like enzyme for ufmylation) cause severe early-onset encephalopathy with progressive microcephaly implicates ufmylation in human brain development. More recently, a homozygous UFM1 variant was proposed as a candidate aetiology of severe early-onset encephalopathy with progressive microcephaly. Here, we establish a locus for severe early-onset encephalopathy with progressive microcephaly based on two families, and map the phenotype to a novel homozygous UFM1 mutation. This mutation has a significantly diminished capacity to form thioester intermediates with UBA5 and with UFC1 (the E2-like enzyme for ufmylation), with resulting impaired ufmylation of cellular proteins. Remarkably, in four additional families where eight children have severe early-onset encephalopathy with progressive microcephaly, we identified two biallelic UFC1 mutations, which impair UFM1-UFC1 intermediate formation with resulting widespread reduction of cellular ufmylation, a pattern similar to that observed with UFM1 mutation. The striking resemblance between UFM1- and UFC1-related clinical phenotype and biochemical derangements strongly argues for an essential role for ufmylation in human brain development. The hypomorphic nature of UFM1 and UFC1 mutations and the conspicuous depletion of biallelic null mutations in the components of this pathway in human genome databases suggest that it is necessary for embryonic survival, which is consistent with the embryonic lethal nature of knockout models for the orthologous genes.

A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost.

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Han, Heping; Vila-Aiub, Martin M; Jalaludin, Adam; Yu, Qin; Powles, Stephen B

2017-12-01

A novel glyphosate resistance double point mutation (T102I/P106S, TIPS) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene has been recently identified for the first time only in the weed species Eleusine indica. Quantification of plant resistance cost associated with the TIPS and the often reported glyphosate resistance single P106S mutation was performed. A significant resistance cost (50% in seed number currency) associated with the homozygous TIPS but not the homozygous P106S EPSPS variant was identified in E. indica plants. The resistance cost associated with the TIPS mutation escalated to 85% in plants under resource competition with rice crops. The resistance cost was not detected in nonhomozygous TIPS plants denoting the recessive nature of the cost associated with the TIPS allele. An excess of 11-fold more shikimate and sixfold more quinate in the shikimate pathway was detected in TIPS plants in the absence of glyphosate treatment compared to wild type, whereas no changes in these compounds were observed in P106S plants when compared to wild type. TIPS plants show altered metabolite levels in several other metabolic pathways that may account for the expression of the observed resistance cost. © 2017 John Wiley & Sons Ltd.

Diagnosis of Xeroderma Pigmentosum Groups A and C by Detection of Two Prevalent Mutations in West Algerian Population: A Rapid Genotyping Tool for the Frequent XPC Mutation c.1643_1644delTG.

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Bensenouci, Salima; Louhibi, Lotfi; De Verneuil, Hubert; Mahmoudi, Khadidja; Saidi-Mehtar, Nadhira

2016-01-01

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder. Considering that XP patients have a defect of the nucleotide excision repair (NER) pathway which enables them to repair DNA damage caused by UV light, they have an increased risk of developing skin and eyes cancers. In the present study, we investigated the involvement of the prevalent XPA and XPC genes mutations-nonsense mutation (c.682C>T, p.Arg228X) and a two-base-pair (2 bp) deletion (c.1643_1644delTG or p.Val548Ala fsX25), respectively-in 19 index cases from 19 unrelated families in the West of Algeria. For the genetic diagnosis of XPA gene, we proceeded to PCR-RFLP. For the XPC gene, we validated a routine analysis which includes a specific amplification of a short region surrounding the 2 bp deletion using a fluorescent primer and fragment sizing (GeneScan size) on a sequencing gel. Among the 19 index cases, there were 17 homozygous patients for the 2 bp deletion in the XPC gene and 2 homozygous patients carrying the nonsense XPA mutation. Finally, XPC appears to be the major disease-causing gene concerning xeroderma pigmentosum in North Africa. The use of fragment sizing is the simplest method to analyze this 2 bp deletion for the DNA samples coming from countries where the mutation c.1643_1644delTG of XPC gene is prevalent.

Gene mutations in children with chronic pancreatitis.

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Witt, H

2001-01-01

In the last few years, several genes have been identified as being associated with hereditary and idiopathic chronic pancreatitis (CP), i.e. PRSS1, CFTR and SPINK1. In this study, we investigated 164 unrelated children and adolescents with CP for mutations in disease-associated genes by direct DNA sequencing, SSCP, RFLP and melting curve analysis. In 15 patients, we detected a PRSS1 mutation (8 with A16V, 5 with R122H, 2 with N29I), and in 34 patients, a SPINK1 mutation (30 with N34S, 4 with others). SPINK1 mutations were predominantly found in patients without a family history (29/121). Ten patients were homozygous for N34S, SPINK1 mutations were most common in 'idiopathic' CP, whereas patients with 'hereditary' CP predominantly showed a PRSS1 mutation (R122H, N29I). In patients without a family history, the most common PRSS1 mutation was A16V (7/121). In conclusion, our data suggest that CP may be inherited in a dominant, recessive or multigenetic manner as a result of mutations in the above-mentioned or as yet unidentified genes. This challenges the concept of idiopathic CP as a nongenetic disorder and the differentiation between hereditary and idiopathic CP. Therefore, we propose to classify CP as either 'primary CP' (with or without a family history) or 'secondary CP' caused by toxic, metabolic or other factors.

Drosophila QVR/SSS modulates the activation and C-type inactivation kinetics of Shaker K+ channels

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Dean, Terry; Xu, Rong; Joiner, William; Sehgal, Amita; Hoshi, Toshinori

2011-01-01

The quiver/sleepless (qvr/sss) gene encodes a small, glycosylphosphatidylinositol-anchored protein that plays a critical role in the regulation of sleep in Drosophila. Loss-of-function mutations in qvr/sss severely suppress sleep and effect multiple changes in in situ Shaker K+ currents, including decreased magnitude, slower time-to-peak, and cumulative inactivation. Recently, we demonstrated that SLEEPLESS (SSS) protein modulates Shaker channel activity, possibly through a direct interaction at the plasma membrane. We show here that SSS accelerates the activation of heterologously expressed Shaker channels with no effect on deactivation or fast N-type inactivation. Furthermore, this SSS-induced acceleration is sensitive to the pharmacological disruption of lipid rafts and sufficiently accounts for the slower time-to-peak of in situ Shaker currents seen in qvr/sss mutants. We also find that SSS decreases the rate of C-type inactivation of heterologously expressed Shaker channels, providing a potential mechanism for the cumulative inactivation phenotype induced by qvr/sss loss of function mutations. Kinetic modeling based on the in vitro results suggests that the SSS-dependent regulation of channel kinetics accounts for nearly 40% of the decrease in Shaker current magnitude in flies lacking SSS. Sleep duration in qvr/sss null mutants is restored to normal by a qvr/sss transgene that fully rescues the Shaker kinetic phenotypes but only partially rescues the decrease in current magnitude. Together, these results suggest that the role of SSS in the regulation of sleep in Drosophila correlates more strongly with the effects of SSS on Shaker kinetics than current magnitude. PMID:21813698

Drosophila QVR/SSS modulates the activation and C-type inactivation kinetics of Shaker K(+) channels.

Science.gov (United States)

Dean, Terry; Xu, Rong; Joiner, William; Sehgal, Amita; Hoshi, Toshinori

2011-08-03

The quiver/sleepless (qvr/sss) gene encodes a small, glycosylphosphatidylinositol-anchored protein that plays a critical role in the regulation of sleep in Drosophila. Loss-of-function mutations in qvr/sss severely suppress sleep and effect multiple changes in in situ Shaker K(+) currents, including decreased magnitude, slower time-to-peak, and cumulative inactivation. Recently, we demonstrated that SLEEPLESS (SSS) protein modulates Shaker channel activity, possibly through a direct interaction at the plasma membrane. We show here that SSS accelerates the activation of heterologously expressed Shaker channels with no effect on deactivation or fast N-type inactivation. Furthermore, this SSS-induced acceleration is sensitive to the pharmacological disruption of lipid rafts and sufficiently accounts for the slower time-to-peak of in situ Shaker currents seen in qvr/sss mutants. We also find that SSS decreases the rate of C-type inactivation of heterologously expressed Shaker channels, providing a potential mechanism for the cumulative inactivation phenotype induced by qvr/sss loss-of-function mutations. Kinetic modeling based on the in vitro results suggests that the SSS-dependent regulation of channel kinetics accounts for nearly 40% of the decrease in Shaker current magnitude in flies lacking SSS. Sleep duration in qvr/sss-null mutants is restored to normal by a qvr/sss transgene that fully rescues the Shaker kinetic phenotypes but only partially rescues the decrease in current magnitude. Together, these results suggest that the role of SSS in the regulation of sleep in Drosophila correlates more strongly with the effects of SSS on Shaker kinetics than current magnitude.

Conditional inactivation of Brca1 in the mouse ovarian surface epithelium results in an increase in preneoplastic changes

International Nuclear Information System (INIS)

Clark-Knowles, Katherine V.; Garson, Kenneth; Jonkers, Jos; Vanderhyden, Barbara C.

2007-01-01

Epithelial ovarian cancer (EOC) is thought to arise from the ovarian surface epithelium (OSE); however, the molecular events underlying this transformation are poorly understood. Germline mutations in the BRCA1 tumor suppressor gene result in a significantly increased risk of developing EOC and a large proportion of sporadic EOCs display some sort of BRCA1 dysfunction. Using mice with conditional expression of Brca1, we inactivated Brca1 in the murine OSE and demonstrate that this inactivation results in the development of preneoplastic changes, such as hyperplasia, epithelial invaginations, and inclusion cysts, which arise earlier and are more numerous than in control ovaries. These changes resemble the premalignant lesions that have been reported in human prophylactic oophorectomy specimens from women with BRCA1 germline mutation. We also report that inactivation of Brca1 in primary cultures of murine OSE cells leads to a suppression of proliferation due to increased apoptosis that can be rescued by concomitant inactivation of p53. These observations, along with our finding that these cells display an increased sensitivity to the DNA-damaging agent cisplatin, indicate that loss of function of Brca1 in OSE cells impacts both cellular growth control and DNA-damage repair which results in altered cell behavior manifested as morphological changes in vivo that arise earlier and are more numerous than what can be attributed to ageing

p.H1069Q mutation in ATP7B and biochemical parameters of copper metabolism and clinical manifestation of Wilson's disease.

Science.gov (United States)

Gromadzka, Graznya; Schmidt, Harmut H J; Genschel, Janine; Bochow, Bettina; Rodo, M; Tarnacka, Beatek; Litwin, Thomas; Chabik, Grzegorz; Członkowska, Anna

2006-02-01

We compared the effect of the p.H1069Q mutation and other non-p.H1069Q mutations in ATP7B on the phenotypic expression of Wilson's disease (WD), and assessed whether the clinical phenotype of WD in compound heterozygotes depends on the type of mutation coexisting with the p.H1069Q. One hundred forty-two patients with clinically, biochemically, and genetically diagnosed WD were studied. The mutational analysis of ATP7B was performed by direct sequencing. A total number of 26 mutations in ATP7B were identified. The p.His1069Gln was the most common mutation (allelic frequency: 72%). Seventy-three patients were homozygous for this mutation. Of compound heterozygotes, 37 had frameshift/nonsense mutation, and 20 had other missense mutation on one of their ATP7B alleles. Twelve patients had two non-p.H1069Q mutations. Patients homozygous for the p.H1069Q mutation had the less severe disturbances of copper metabolism and the latest presentation of first WD symptoms. The most severely disturbed copper metabolism and the earliest age at initial disease manifestation was noticed in non-p.H1069Q patients. In compound heterozygotes, the type of mutation coexisting with the p.H1069Q to a small extent influenced WD phenotype. The phenotype of WD varied considerably among patients with the same genotype. The p.H1069Q mutation is associated with late WD manifestation and with a mild disruption of copper metabolism. In compound heterozygotes, the phenotype of WD to a small extent depends on the type of mutation coexisting with the p.H1069Q. Besides genotype, additional modifying factors seem to determine WD manifestations. Copyright (c) 2005 Movement Disorder Society.

Neuropathology of the recessive A673V APP mutation: Alzheimer disease with distinctive features.

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Giaccone, Giorgio; Morbin, Michela; Moda, Fabio; Botta, Mario; Mazzoleni, Giulia; Uggetti, Andrea; Catania, Marcella; Moro, Maria Luisa; Redaelli, Veronica; Spagnoli, Alberto; Rossi, Roberta Simona; Salmona, Mario; Di Fede, Giuseppe; Tagliavini, Fabrizio

2010-12-01

Mutations of three different genes, encoding β-amyloid precursor protein (APP), presenilin 1 and presenilin 2 are associated with familial Alzheimer's disease (AD). Recently, the APP mutation A673V has been identified that stands out from all the genetic defects previously reported in these three genes, since it causes the disease only in the homozygous state (Di Fede et al. in Science 323:1473-1477, 2009). We here provide the detailed neuropathological picture of the proband of this family, who was homozygous for the APP A673V mutation and recently came to death. The brain has been studied by histological and immunohistochemical techniques, at the optical and ultrastructural levels. Cerebral Aβ accumulation and tau pathology were severe and extensive. Peculiar features were the configuration of the Aβ deposits that were of large size, mostly perivascular and exhibited a close correspondence between the pattern elicited by amyloid stainings and the labeling obtained with immunoreagents specific for Aβ40 or Aβ42. Moreover, Aβ deposition spared the neostriatum while deeply affecting the cerebellum, and therefore was not in compliance with the hierarchical topographical sequence of involvement documented in sporadic AD. Therefore, the neuropathological picture of familial AD caused by the APP recessive mutation A673V presents distinctive characteristics compared to sporadic AD or familial AD inherited as a dominant trait. Main peculiar features are the morphology, structural properties and composition of the Aβ deposits as well as their topographic distribution in the brain.

The Eag domain regulates the voltage-dependent inactivation of rat Eag1 K+ channels.

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Ting-Feng Lin

Full Text Available Eag (Kv10 and Erg (Kv11 belong to two distinct subfamilies of the ether-à-go-go K+ channel family (KCNH. While Erg channels are characterized by an inward-rectifying current-voltage relationship that results from a C-type inactivation, mammalian Eag channels display little or no voltage-dependent inactivation. Although the amino (N-terminal region such as the eag domain is not required for the C-type inactivation of Erg channels, an N-terminal deletion in mouse Eag1 has been shown to produce a voltage-dependent inactivation. To further discern the role of the eag domain in the inactivation of Eag1 channels, we generated N-terminal chimeras between rat Eag (rEag1 and human Erg (hERG1 channels that involved swapping the eag domain alone or the complete cytoplasmic N-terminal region. Functional analyses indicated that introduction of the homologous hERG1 eag domain led to both a fast phase and a slow phase of channel inactivation in the rEag1 chimeras. By contrast, the inactivation features were retained in the reverse hERG1 chimeras. Furthermore, an eag domain-lacking rEag1 deletion mutant also showed the fast phase of inactivation that was notably attenuated upon co-expression with the rEag1 eag domain fragment, but not with the hERG1 eag domain fragment. Additionally, we have identified a point mutation in the S4-S5 linker region of rEag1 that resulted in a similar inactivation phenotype. Biophysical analyses of these mutant constructs suggested that the inactivation gating of rEag1 was distinctly different from that of hERG1. Overall, our findings are consistent with the notion that the eag domain plays a critical role in regulating the inactivation gating of rEag1. We propose that the eag domain may destabilize or mask an inherent voltage-dependent inactivation of rEag1 K+ channels.

six novel mutations in the TSC1 and TSC2 genes

Indian Academy of Sciences (India)

M. GLUSHKOVA

2018-04-30

Apr 30, 2018 ... RESEARCH ARTICLE ... nant disorder caused by inactivating TSC1 or TSC2 gene variants (Van ... premature protein truncation, while missense mutations are rare ..... TSC2 variants in our cohort are missense, frame-shift.

Detection of new paternal dystrophin gene mutations in isolated cases of dystrophinopathy in females

Energy Technology Data Exchange (ETDEWEB)

Pegoraro, E.; Wessel, H.B.; Schwartz, L.; Hoffman, E.P. (Univ. of Pittsburgh, PA (United States)); Schimke, R.N. (Kansas Univ. Medical Center, Kansas City (United States)); Arahata, Kiichi; Hayashi, Yukiko (National Institute of Neurosciences, Tokyo (Japan)); Stern, H. (Children' s National Medical Center, Washington, DC (United States)); Marks, H. (A.I. duPont Institute, Wilmington (United States)); Glasberg, M.R. (Henry Ford Hospital, Detroit, MI (United States)) (and others)

1994-06-01

Duchenne muscular dystrophy is one of the most common lethal monogenic disorders and is caused by dystrophin deficiency. The disease is transmitted as an X-linked recessive trait; however, recent biochemical and clinical studies have shown that many girls and women with a primary myopathy have an underlying dystrophinopathy, despite a negative family history for Duchenne dystrophy. These isolated female dystrophinopathy patients carried ambiguous diagnoses with presumed autosomal recessive inheritance (limb-girdle muscular dystrophy) prior to biochemical detection of dystrophin abnormalities in their muscle biopsy. It has been assumed that these female dystrophinopathy patients are heterozygous carries who show preferential inactivation of the X chromosome harboring the normal dystrophin gene, although this has been shown for only a few X:autosome translocations and for two cases of discordant monozygotic twin female carriers. Here the authors study X-inactivation patterns of 13 female dystrophinopathy patients - 10 isolated cases and 3 cases with a positive family history for Duchenne dystrophy in males. They show that all cases have skewed X-inactivation patterns in peripheral blood DNA. Of the nine isolated cases informative in the assay, eight showed inheritance of the dystrophin gene mutation from the paternal germ line. Only a single case showed maternal inheritance. The 10-fold higher incidence of paternal transmission of dystrophin gene mutations in these cases is at 30-fold variance with Bayesian predictions and gene mutation rates. Thus, the results suggest some mechanistic interaction between new dystrophin gene mutations, paternal inheritance, and skewed X inactivation. The results provide both empirical risk data and a molecular diagnostic test method, which permit genetic counseling and prenatal diagnosis of this new category of patients. 58 refs., 7 figs., 2 tabs.

A novel homozygous missense variant in NECTIN4 (PVRL4) causing ectodermal dysplasia cutaneous syndactyly syndrome.

Science.gov (United States)

Ahmad, Farooq; Nasir, Abdul; Thiele, Holger; Umair, Muhammad; Borck, Guntram; Ahmad, Wasim

2018-02-12

Ectodermal dysplasia syndactyly syndrome 1 (EDSS1) is a rare form of ectodermal dysplasia including anomalies of hair, nails, and teeth along with bilateral cutaneous syndactyly of hands and feet. In the present report, we performed a clinical and genetic characterization of a consanguineous Pakistani family with four individuals affected by EDSS1. We performed exome sequencing using DNA of one affected individual. Exome data analysis identified a novel homozygous missense variant (c.242T>C; p.(Leu81Pro)) in NECTIN4 (PVRL4). Sanger sequencing validated this variant and confirmed its cosegregation with the disease phenotype in the family members. Thus, our report adds a novel variant to the NECTIN4 mutation spectrum and contributes to the NECTIN4-related clinical characterization. © 2018 John Wiley & Sons Ltd/University College London.

Premature Valvular Heart Disease in Homozygous Familial Hypercholesterolemia

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Akl C. Fahed

2017-01-01

Full Text Available Valvular heart disease frequently occurs as a consequence of premature atherosclerosis in individuals with familial hypercholesterolemia (FH. Studies have primarily focused on aortic valve calcification in heterozygous FH, but there is paucity of data on the incidence of valvular disease in homozygous FH. We performed echocardiographic studies in 33 relatively young patients (mean age: 26 years with homozygous FH (mean LDL of 447 mg/dL, 73% on LDL apheresis to look for subclinical valvulopathy. Twenty-one patients had evidence of valvulopathy of the aortic or mitral valves, while seven subjects showed notable mitral regurgitation. Older patients were more likely to have aortic valve calcification (>21 versus ≤21 years: 59% versus 12.5%; p = 0.01 despite lower LDL levels at the time of the study (385 versus 513 mg/dL; p = 0.016. Patients with valvulopathy were older and had comparable LDL levels and a lower carotid intima-media thickness. Our data suggests that, in homozygous FH patients, valvulopathy (1 is present across a wide age spectrum and LDL levels and (2 is less likely to be influenced by lipid-lowering treatment. Echocardiographic studies that focused on aortic root thickening and stenosis and regurgitation are thus likely an effective modality for serial follow-up of subclinical valvular heart disease.

FATP4 missense and nonsense mutations cause similar features in Ichthyosis Prematurity Syndrome

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Dahl Niklas

2011-03-01

Full Text Available Abstract Background Ichthyosis Prematurity Syndrome (IPS is an autosomal recessive disorder characterized by premature birth, non-scaly ichthyosis and atopic manifestations. The disease was recently shown to be caused by mutations in the gene encoding the fatty acid transport protein 4 (FATP4 and a specific reduction in the incorporation of very long chain fatty acids (VLCFA into cellular lipids. Findings We screened probands from five families segregating IPS for mutations in the FATP4 gene. Four probands were compound heterozygous for four different mutations of which three are novel. Four patients were heterozygous and one patient homozygous for the previously reported non-sense mutation p.C168X (c.504c > a. All patients had clinical characteristics of IPS and a similar clinical course. Conclusions Missense mutations and non-sense mutations in FATP4 are associated with similar clinical features suggesting that missense mutations have a severe impact on FATP4 function. The results broaden the mutational spectrum in FATP4 associated with IPS for molecular diagnosis of and further functional analysis of FATP4.

Novel mutations of endothelin-B receptor gene in Pakistani patients with Waardenburg syndrome.

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Jabeen, Raheela; Babar, Masroor Ellahi; Ahmad, Jamil; Awan, Ali Raza

2012-01-01

Mutations in EDNRB gene have been reported to cause Waardenburg-Shah syndrome (WS4) in humans. We investigated 17 patients with WS4 for identification of mutations in EDNRB gene using PCR and direct sequencing technique. Four genomic mutations were detected in four patients; a G to C transversion in codon 335 (S335C) in exon 5 and a transition of T to C in codon (S361L) in exon 5, a transition of A to G in codon 277 (L277L) in exon 4, a non coding transversion of T to A at -30 nucleotide position of exon 5. None of these mutations were found in controls. One of the patients harbored two novel mutations (S335C, S361L) in exon 5 and one in Intronic region (-30exon5 A>G). All of the mutations were homozygous and novel except the mutation observed in exon 4. In this study, we have identified 3 novel mutations in EDNRB gene associated with WS4 in Pakistani patients.

The production of homozygous tree material

Science.gov (United States)

Reinhard F. Stettler; George E. Howe

1966-01-01

Homozygous trees will never be the desired ultimate step in a forest tree improvement program. However, they will serve many purposes in forest genetics research: (1) in the detection of genetic markers; (2) in the isolation of traits under simple genetic control for the study of growth and differentiation phenomena; (3) as a tool as well as reference material in the...

A recessive founder mutation in regulator of telomere elongation helicase 1, RTEL1, underlies severe immunodeficiency and features of Hoyeraal Hreidarsson syndrome.

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Ballew, Bari J; Joseph, Vijai; De, Saurav; Sarek, Grzegorz; Vannier, Jean-Baptiste; Stracker, Travis; Schrader, Kasmintan A; Small, Trudy N; O'Reilly, Richard; Manschreck, Chris; Harlan Fleischut, Megan M; Zhang, Liying; Sullivan, John; Stratton, Kelly; Yeager, Meredith; Jacobs, Kevin; Giri, Neelam; Alter, Blanche P; Boland, Joseph; Burdett, Laurie; Offit, Kenneth; Boulton, Simon J; Savage, Sharon A; Petrini, John H J

2013-08-01

Dyskeratosis congenita (DC) is a heterogeneous inherited bone marrow failure and cancer predisposition syndrome in which germline mutations in telomere biology genes account for approximately one-half of known families. Hoyeraal Hreidarsson syndrome (HH) is a clinically severe variant of DC in which patients also have cerebellar hypoplasia and may present with severe immunodeficiency and enteropathy. We discovered a germline autosomal recessive mutation in RTEL1, a helicase with critical telomeric functions, in two unrelated families of Ashkenazi Jewish (AJ) ancestry. The affected individuals in these families are homozygous for the same mutation, R1264H, which affects three isoforms of RTEL1. Each parent was a heterozygous carrier of one mutant allele. Patient-derived cell lines revealed evidence of telomere dysfunction, including significantly decreased telomere length, telomere length heterogeneity, and the presence of extra-chromosomal circular telomeric DNA. In addition, RTEL1 mutant cells exhibited enhanced sensitivity to the interstrand cross-linking agent mitomycin C. The molecular data and the patterns of inheritance are consistent with a hypomorphic mutation in RTEL1 as the underlying basis of the clinical and cellular phenotypes. This study further implicates RTEL1 in the etiology of DC/HH and immunodeficiency, and identifies the first known homozygous autosomal recessive disease-associated mutation in RTEL1.

A recessive founder mutation in regulator of telomere elongation helicase 1, RTEL1, underlies severe immunodeficiency and features of Hoyeraal Hreidarsson syndrome.

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Bari J Ballew

2013-08-01

Full Text Available Dyskeratosis congenita (DC is a heterogeneous inherited bone marrow failure and cancer predisposition syndrome in which germline mutations in telomere biology genes account for approximately one-half of known families. Hoyeraal Hreidarsson syndrome (HH is a clinically severe variant of DC in which patients also have cerebellar hypoplasia and may present with severe immunodeficiency and enteropathy. We discovered a germline autosomal recessive mutation in RTEL1, a helicase with critical telomeric functions, in two unrelated families of Ashkenazi Jewish (AJ ancestry. The affected individuals in these families are homozygous for the same mutation, R1264H, which affects three isoforms of RTEL1. Each parent was a heterozygous carrier of one mutant allele. Patient-derived cell lines revealed evidence of telomere dysfunction, including significantly decreased telomere length, telomere length heterogeneity, and the presence of extra-chromosomal circular telomeric DNA. In addition, RTEL1 mutant cells exhibited enhanced sensitivity to the interstrand cross-linking agent mitomycin C. The molecular data and the patterns of inheritance are consistent with a hypomorphic mutation in RTEL1 as the underlying basis of the clinical and cellular phenotypes. This study further implicates RTEL1 in the etiology of DC/HH and immunodeficiency, and identifies the first known homozygous autosomal recessive disease-associated mutation in RTEL1.

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

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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.

Whole-Genome Sequence of the Metastatic PC3 and LNCaP Human Prostate Cancer Cell Lines

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Inge Seim

2017-06-01

Full Text Available The bone metastasis-derived PC3 and the lymph node metastasis-derived LNCaP prostate cancer cell lines are widely studied, having been described in thousands of publications over the last four decades. Here, we report short-read whole-genome sequencing (WGS and de novo assembly of PC3 (ATCC CRL-1435 and LNCaP (clone FGC; ATCC CRL-1740 at ∼70 × coverage. A known homozygous mutation in TP53 and homozygous loss of PTEN were robustly identified in the PC3 cell line, whereas the LNCaP cell line exhibited a larger number of putative inactivating somatic point and indel mutations (and in particular a loss of stop codon events. This study also provides preliminary evidence that loss of one or both copies of the tumor suppressor Capicua (CIC contributes to primary tumor relapse and metastatic progression, potentially offering a treatment target for castration-resistant prostate cancer (CRPC. Our work provides a resource for genetic, genomic, and biological studies employing two commonly-used prostate cancer cell lines.

Whole-Genome Sequence of the Metastatic PC3 and LNCaP Human Prostate Cancer Cell Lines.

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Seim, Inge; Jeffery, Penny L; Thomas, Patrick B; Nelson, Colleen C; Chopin, Lisa K

2017-06-07

The bone metastasis-derived PC3 and the lymph node metastasis-derived LNCaP prostate cancer cell lines are widely studied, having been described in thousands of publications over the last four decades. Here, we report short-read whole-genome sequencing (WGS) and de novo assembly of PC3 (ATCC CRL-1435) and LNCaP (clone FGC; ATCC CRL-1740) at ∼70 × coverage. A known homozygous mutation in TP53 and homozygous loss of PTEN were robustly identified in the PC3 cell line, whereas the LNCaP cell line exhibited a larger number of putative inactivating somatic point and indel mutations (and in particular a loss of stop codon events). This study also provides preliminary evidence that loss of one or both copies of the tumor suppressor Capicua ( CIC ) contributes to primary tumor relapse and metastatic progression, potentially offering a treatment target for castration-resistant prostate cancer (CRPC). Our work provides a resource for genetic, genomic, and biological studies employing two commonly-used prostate cancer cell lines. Copyright © 2017 Seim et al.

Inactivation of ultraviolet repair in normal and xeroderma pigmentosum cells by methyl methanesulfonate

International Nuclear Information System (INIS)

Cleaver, J.E.

1982-01-01

Excision repair of ultraviolet damage in the DNA of normal and xeroderma pigmentosum (Groups C, D, and variant) cells was inactivated by exposure of cells to methyl methanesulfonate immediately before irradiation independent of the presence of 0 to 10% fetal calf serum. The inactivation could be represented by a semilog relationship between the amount of repair and methyl methanesulfonate concentration up to approximately 5 mM. The inactivation can be considered to occur as the result of alkylation of a large (about 10(6) daltons) repair enzyme complex, and the dose required to reduce repair to 37% for most cells types was between 4 and 7 mM. No consistent, large difference in sensitivity to methyl methanesulfonate was found in any xeroderma pigmentosum complementation group compared to normal cells, implying that reduced repair in these groups may be caused by small inherited changes in the amino acid composition (i.e., point mutations or small deletions) rather than by losses of major components of the repair enzyme complex

Cortical synaptic transmission in CaV2.1 knockin mice with the S218L missense mutation which causes a severe familial hemiplegic migraine syndrome in humans.

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Dania eVecchia

2015-02-01

Full Text Available Familial hemiplegic migraine type 1 (FHM1 is caused by gain-of-function mutations in CaV2.1 (P/Q-type Ca2+ channels. Knockin (KI mice carrying the FHM1 R192Q missense mutation show enhanced cortical excitatory synaptic transmission at pyramidal cell synapses but unaltered cortical inhibitory neurotransmission at fast-spiking interneuron synapses. Enhanced cortical glutamate release was shown to cause the facilitation of cortical spreading depression (CSD in R192Q KI mice. It, however, remains unknown how other FHM1 mutations affect cortical synaptic transmission. Here, we studied neurotransmission in cortical neurons in microculture from KI mice carrying the S218L mutation, which causes a severe FHM syndrome in humans and an allele-dosage dependent facilitation of experimental CSD in KI mice, which is larger than that caused by the R192Q mutation. We show gain-of-function of excitatory neurotransmission, due to increased action-potential evoked Ca2+ influx and increased probability of glutamate release at pyramidal cell synapses, but unaltered inhibitory neurotransmission at multipolar interneuron synapses in S218L KI mice. In contrast with the larger gain-of-function of neuronal CaV2.1 current in homozygous than heterozygous S218L KI mice, the gain-of-function of evoked glutamate release, the paired-pulse ratio and the Ca2+ dependence of the EPSC were all similar in homozygous and heterozygous S218L KI mice, suggesting compensatory changes in the homozygous mice. Furthermore, we reveal a unique feature of S218L KI cortical synapses which is the presence of a fraction of mutant CaV2.1 channels being open at resting potential. Our data suggest that, while the gain-of-function of evoked glutamate release may explain the facilitation of CSD in heterozygous S218L KI mice, the further facilitation of CSD in homozygous S218L KI mice is due to other CaV2.1-dependent mechanisms, that likely include Ca2+ influx at voltages sub-threshold for action

The effects of MSH2 deficiency on spontaneous and radiation-induced mutation rates in the mouse germline

International Nuclear Information System (INIS)

Burr, Karen L-A.; Duyn-Goedhart, Annemarie van; Hickenbotham, Peter; Monger, Karen; Buul, Paul P.W. van; Dubrova, Yuri E.

2007-01-01

Mutation rates at two expanded simple tandem repeat (ESTR) loci were studied in the germline of mismatch repair deficient Msh2 knock-out mice. Spontaneous mutation rates in homozygous Msh2 -/- males were significantly higher than those in isogenic wild-type (Msh2 +/+ ) and heterozygous (Msh2 +/- ) mice. In contrast, the irradiated Msh2 -/- mice did not show any detectable increases in their mutation rate, whereas significant ESTR mutation induction was observed in the irradiated Msh2 +/+ and Msh2 +/- animals. Considering these data and the results of other publications, we propose that the Msh2-deficient mice possess a mutator phenotype in their germline and somatic tissues while the loss of a single Msh2 allele does not affect the stability of heterozygotes

Separating genetic and hemodynamic defects in neuropilin 1 knockout embryos.

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Jones, Elizabeth A V; Yuan, Li; Breant, Christine; Watts, Ryan J; Eichmann, Anne

2008-08-01

Targeted inactivation of genes involved in murine cardiovascular development frequently leads to abnormalities in blood flow. As blood fluid dynamics play a crucial role in shaping vessel morphology, the presence of flow defects generally prohibits the precise assignment of the role of the mutated gene product in the vasculature. In this study, we show how to distinguish between genetic defects caused by targeted inactivation of the neuropilin 1 (Nrp1) receptor and hemodynamic defects occurring in homozygous knockout embryos. Our analysis of a Nrp1 null allele bred onto a C57BL/6 background shows that vessel remodeling defects occur concomitantly with the onset of blood flow and cause death of homozygous mutants at E10.5. Using mouse embryo culture, we establish that hemodynamic defects are already present at E8.5 and continuous circulation is never established in homozygous mutants. The geometry of yolk sac blood vessels is altered and remodeling into yolk sac arteries and veins does not occur. To separate flow-induced deficiencies from those caused by the Nrp1 mutation, we arrested blood flow in cultured wild-type and mutant embryos and followed their vascular development. We find that loss of Nrp1 function rather than flow induces the altered geometry of the capillary plexus. Endothelial cell migration, but not replication, is altered in Nrp1 mutants. Gene expression analysis of endothelial cells isolated from freshly dissected wild-type and mutants and after culture in no-flow conditions showed down-regulation of the arterial marker genes connexin 40 and ephrin B2 related to the loss of Nrp1 function. This method allows genetic defects caused by loss-of-function of a gene important for cardiovascular development to be isolated even in the presence of hemodynamic defects.

Driver mutations (JAK2V617F, MPLW515L/K or CALR), pentraxin-3 and C-reactive protein in essential thrombocythemia and polycythemia vera.

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Lussana, Federico; Carobbio, Alessandra; Salmoiraghi, Silvia; Guglielmelli, Paola; Vannucchi, Alessandro Maria; Bottazzi, Barbara; Leone, Roberto; Mantovani, Alberto; Barbui, Tiziano; Rambaldi, Alessandro

2017-02-22

The driver mutations JAK2V617F, MPLW515L/K and CALR influence disease phenotype of myeloproliferative neoplasms (MPNs) and might sustain a condition of chronic inflammation. Pentraxin 3 (PTX3) and high-sensitivity C-reactive protein (hs-CRP) are inflammatory biomarkers potentially useful for refining prognostic classification of MPNs. We evaluated 305 with essential thrombocythemia (ET) and 172 polycythemia vera (PV) patients diagnosed according to the 2016 WHO criteria and with full molecular characterization for driver mutations. PTX3 levels were significantly increased in carriers of homozygous JAK2V617F mutation compared to all the other genotypes and triple negative ET patients, while hs-CRP levels were independent of the mutational profile. The risk of haematological evolution and death from any cause was about 2- and 1.5-fold increased in individuals with high PTX-3 levels, while the thrombosis rate tended to be lower. High hs-CRP levels were associated with risk of haematological evolution, death and also major thrombosis. After sequential adjustment for potential confounders (age, gender, diagnosis and treatments) and the presence of JAK2V617F homozygous status, high hs-CRP levels remained significant for all outcomes, while JAK2V617F homozygous status as well as treatments were the factors independently accounting for adverse outcomes among patients with high PTX3 levels. These results provide evidence that JAK2V617F mutation influences MPN-associated inflammation with a strong correlation between allele burden and PTX3 levels. Plasma levels of hs-CRP and PTX3 might be of prognostic value for patients with ET and PV, but their validation in future prospective studies is needed.

Mechanistic Basis for Type 2 Long QT Syndrome Caused by KCNH2 Mutations that Disrupt Conserved Arginine Residue in the Voltage Sensor

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McBride, Christie M.; Smith, Ashley M.; Smith, Jennifer L.; Reloj, Allison R.; Velasco, Ellyn J.; Powell, Jonathan; Elayi, Claude S.; Bartos, Daniel C.; Burgess, Don E.

2013-01-01

KCNH2 encodes the Kv11.1 channel, which conducts the rapidly activating delayed rectifier K+ current (IKr) in the heart. KCNH2 mutations cause type 2 long QT syndrome (LQT2), which increases the risk for life-threatening ventricular arrhythmias. LQT2 mutations are predicted to prolong the cardiac action potential (AP) by reducing IKr during repolarization. Kv11.1 contains several conserved basic amino acids in the fourth transmembrane segment (S4) of the voltage sensor that are important for normal channel trafficking and gating. This study sought to determine the mechanism(s) by which LQT2 mutations at conserved arginine residues in S4 (R531Q, R531W or R534L) alter Kv11.1 function. Western blot analyses of HEK293 cells transiently expressing R531Q, R531W or R534L suggested that only R534L inhibited Kv11.1 trafficking. Voltage-clamping experiments showed that R531Q or R531W dramatically altered Kv11.1 current (IKv11.1) activation, inactivation, recovery from inactivation and deactivation. Coexpression of wild type (to mimic the patients’ genotypes) mostly corrected the changes in IKv11.1 activation and inactivation, but deactivation kinetics were still faster. Computational simulations using a human ventricular AP model showed that accelerating deactivation rates was sufficient to prolong the AP, but these effects were minimal compared to simply reducing IKr. These are the first data to demonstrate that coexpressing wild type can correct activation and inactivation dysfunction caused by mutations at a critical voltage-sensing residue in Kv11.1. We conclude that some Kv11.1 mutations might accelerate deactivation to cause LQT2 but that the ventricular AP duration is much more sensitive to mutations that decrease IKr. This likely explains why most LQT2 mutations are nonsense or trafficking-deficient. PMID:23546015

Identification of eight novel coagulation factor XIII subunit A mutations: implied consequences for structure and function.

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Ivaskevicius, Vytautas; Biswas, Arijit; Bevans, Carville; Schroeder, Verena; Kohler, Hans Peter; Rott, Hannelore; Halimeh, Susan; Petrides, Petro E; Lenk, Harald; Krause, Manuele; Miterski, Bruno; Harbrecht, Ursula; Oldenburg, Johannes

2010-06-01

Severe hereditary coagulation factor XIII deficiency is a rare homozygous bleeding disorder affecting one person in every two million individuals. In contrast, heterozygous factor XIII deficiency is more common, but usually not associated with severe hemorrhage such as intracranial bleeding or hemarthrosis. In most cases, the disease is caused by F13A gene mutations. Causative mutations associated with the F13B gene are rarer. We analyzed ten index patients and three relatives for factor XIII activity using a photometric assay and sequenced their F13A and F13B genes. Additionally, structural analysis of the wild-type protein structure from a previously reported X-ray crystallographic model identified potential structural and functional effects of the missense mutations. All individuals except one were heterozygous for factor XIIIA mutations (average factor XIII activity 51%), while the remaining homozygous individual was found to have severe factor XIII deficiency (<5% of normal factor XIII activity). Eight of the 12 heterozygous patients exhibited a bleeding tendency upon provocation. The identified missense (Pro289Arg, Arg611His, Asp668Gly) and nonsense (Gly390X, Trp664X) mutations are causative for factor XIII deficiency. A Gly592Ser variant identified in three unrelated index patients, as well as in 200 healthy controls (minor allele frequency 0.005), and two further Tyr167Cys and Arg540Gln variants, represent possible candidates for rare F13A gene polymorphisms since they apparently do not have a significant influence on the structure of the factor XIIIA protein. Future in vitro expression studies of the factor XIII mutations are required to confirm their pathological mechanisms.

Abnormal cortical synaptic transmission in CaV2.1 knockin mice with the S218L missense mutation which causes a severe familial hemiplegic migraine syndrome in humans

Science.gov (United States)

Vecchia, Dania; Tottene, Angelita; van den Maagdenberg, Arn M.J.M.; Pietrobon, Daniela

2015-01-01

Familial hemiplegic migraine type 1 (FHM1) is caused by gain-of-function mutations in CaV2.1 (P/Q-type) Ca2+ channels. Knockin (KI) mice carrying the FHM1 R192Q missense mutation show enhanced cortical excitatory synaptic transmission at pyramidal cell synapses but unaltered cortical inhibitory neurotransmission at fast-spiking interneuron synapses. Enhanced cortical glutamate release was shown to cause the facilitation of cortical spreading depression (CSD) in R192Q KI mice. It, however, remains unknown how other FHM1 mutations affect cortical synaptic transmission. Here, we studied neurotransmission in cortical neurons in microculture from KI mice carrying the S218L mutation, which causes a severe FHM syndrome in humans and an allele-dosage dependent facilitation of experimental CSD in KI mice, which is larger than that caused by the R192Q mutation. We show gain-of-function of excitatory neurotransmission, due to increased action-potential evoked Ca2+ influx and increased probability of glutamate release at pyramidal cell synapses, but unaltered inhibitory neurotransmission at multipolar interneuron synapses in S218L KI mice. In contrast with the larger gain-of-function of neuronal CaV2.1 current in homozygous than heterozygous S218L KI mice, the gain-of-function of evoked glutamate release, the paired-pulse ratio and the Ca2+ dependence of the excitatory postsynaptic current were similar in homozygous and heterozygous S218L KI mice, suggesting compensatory changes in the homozygous mice. Furthermore, we reveal a unique feature of S218L KI cortical synapses which is the presence of a fraction of mutant CaV2.1 channels being open at resting potential. Our data suggest that, while the gain-of-function of evoked glutamate release may explain the facilitation of CSD in heterozygous S218L KI mice, the further facilitation of CSD in homozygous S218L KI mice is due to other CaV2.1-dependent mechanisms, that likely include Ca2+ influx at voltages sub-threshold for action

Novel duplication mutation in the patatin domain of adipose triglyceride lipase (PNPLA2) in neutral lipid storage disease with severe myopathy.

Science.gov (United States)

Akiyama, Masashi; Sakai, Kaori; Ogawa, Masaya; McMillan, James R; Sawamura, Daisuke; Shimizu, Hiroshi

2007-12-01

Recently, mutations in PNPLA2 encoding adipose triglyceride lipase (ATGL) were reported to underlie a neutral lipid storage disease (NLSD) subgroup characterized by mild myopathy and the absence of ichthyosis. In the present study a novel homozygous PNPLA2 mutation c.475_478dupCTCC (p.Gln160ProfsX19) in the patatin domain, the ATGL active site, was detected in a woman with NLSD and severe myopathy. The present results suggest that a premature truncation mutation in the patatin domain causes NLSD with severe myopathy.

Association of complementation group and mutation type with clinical outcome in fanconi anemia. European Fanconi Anemia Research Group.

Science.gov (United States)

Faivre, L; Guardiola, P; Lewis, C; Dokal, I; Ebell, W; Zatterale, A; Altay, C; Poole, J; Stones, D; Kwee, M L; van Weel-Sipman, M; Havenga, C; Morgan, N; de Winter, J; Digweed, M; Savoia, A; Pronk, J; de Ravel, T; Jansen, S; Joenje, H; Gluckman, E; Mathew, C G

2000-12-15

Fanconi anemia (FA) is a clinically and genetically heterogeneous disorder. Clinical care is complicated by variable age at onset and severity of hematologic symptoms. Recent advances in the molecular biology of FA have allowed us to investigate the relationship between FA genotype and the nature and severity of the clinical phenotype. Two hundred forty-five patients from all 7 known complementation groups (FA-A to FA-G) were studied. Mutations were detected in one of the cloned FANC genes in 169 patients; in the remainder the complementation group was assigned by cell fusion or Western blotting. A range of qualitative and quantitative clinical parameters was compared for each complementation group and for different classes of mutation. Significant phenotypic differences were found. FA-G patients had more severe cytopenia and a higher incidence of leukemia. Somatic abnormalities were less prevalent in FA-C, but more common in the rare groups FA-D, FA-E, and FA-F. In FA-A, patients homozygous for null mutations had an earlier onset of anemia and a higher incidence of leukemia than those with mutations producing an altered protein. In FA-C, there was a later age of onset of aplastic anemia and fewer somatic abnormalities in patients with the 322delG mutation, but there were more somatic abnormalities in patients with IVS4 + 4A --> T. This study indicates that FA patients with mutations in the FANCG gene and patients homozygous for null mutations in FANCA are high-risk groups with a poor hematologic outcome and should be considered as candidates both for frequent monitoring and early therapeutic intervention. (Blood. 2000;96:4064-4070)

Characterization of beta-thalassemia mutations in patients from the state of Rio Grande do Norte, Brazil

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Zama Messala Luna da Silveira

2011-01-01

Full Text Available 35 unrelated individuals were studied for characterization as either heterozygous or homozygous for beta-thalassemia. Molecular analysis was done by PCR/RFLP to detect the mutations most commonly associated with beta-thalassemia (β0IVS-I-1, β+IVS-I-6, and β039. In the patients who showed none of these mutations, the beta-globin genes were sequenced. Of the 31 heterozygous patients, 13 (41.9% had the β+IVS-I-6 mutation, 15 (48.4% the β0IVS-I-1 mutation, 2 (6.5% the β+IVS-I-110 mutation and 1 (3.2% the β+IVS-I-5 mutation. IVS-I-6 was detected in the four homozygotes. The mutation in codon 39, often found in previous studies in Brazil, was not detected in the present case. This is the first study aiming at identifying mutations that determine beta-thalassemia in the state of Rio Grande do Norte.

PROP1 gene mutations in a 36-year-old female presenting with psychosis

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Durgesh Prasad Chaudhary

2017-03-01

Full Text Available Combined pituitary hormonal deficiency (CPHD is a rare disease that results from mutations in genes coding for transcription factors that regulate the differentiation of pituitary cells. PROP1 gene mutations are one of the etiological diagnoses of congenital panhypopituitarism, however symptoms vary depending on phenotypic expression. We present a case of psychosis in a 36-year-old female with congenital panhypopituitarism who presented with paranoia, flat affect and ideas of reference without a delirious mental state, which resolved with hormone replacement and antipsychotics. Further evaluation revealed that she had a homozygous mutation of PROP1 gene. In summary, compliance with hormonal therapy for patients with hypopituitarism appears to be effective for the prevention and treatment of acute psychosis symptoms.

Report of a newly indentified patient with mutations in BMP1 and underlying pathogenetic aspects

DEFF Research Database (Denmark)

Valencia, María; Caparrós-Martin, Jose A; Sirerol-Piquer, María Salomé

2014-01-01

Osteogenesis imperfecta is a genetic condition characterized by bone fragility and recurrent fractures, which in the large majority of patients are caused by defects in the production of type I collagen. Mutations in the gene encoding bone morphogenetic protein 1 (BMP1, also known as procollagen C......-endopeptidase) have been associated with osteogenesis imperfecta in two sib pairs. In this report, we describe an additional patient with osteogenesis imperfecta with normal bone density and a recurrent, homozygous c.34G>C mutation in BMP1. Western blot analysis of dermal fibroblasts from this patient showed...

Molecular analysis of lipoid proteinosis: identification of a novel nonsense mutation in the ECM1 gene in a Pakistani family

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Naeem Muhammad

2011-07-01

Full Text Available Abstract Lipoid proteinosis is a rare autosomal recessive disease characterized by cutaneous and mucosal lesions and hoarseness appearing in early childhood that is caused by homozygous or compound heterozygous mutations in the ECM1 gene located on chromosome 1q21. The aim of the study was to investigate the molecular genetic defect underlying lipoid proteinosis in a consanguineous Pakistani family. Methods Genotyping of seven members of the family was performed by amplifying microsatellite markers, tightly linked to the ECM1 gene. To screen for mutations in the ECM1 gene, all of its exons and splice junctions were PCR amplified from genomic DNA and analyzed by SSCP and sequenced directly in an ABI 3130 genetic analyzer. Results The results revealed linkage of the LP family to the ECM1 locus. Sequence analysis of the coding exons and splice junctions of the ECM1 gene revealed a novel homozygous mutation (c.616C > T in exon 6, predicted to replace glutamine with stop codon (p.Q206X at amino acid position 206. Conclusions The finding of a novel mutation in Pakistani family extends the body of evidence that supports the importance of ECM1 gene for the development of lipoid proteinosis.

Reduced Mutation Rate and Increased Transformability of Transposon-Free Acinetobacter baylyi ADP1-ISx.

Science.gov (United States)

Suárez, Gabriel A; Renda, Brian A; Dasgupta, Aurko; Barrick, Jeffrey E

2017-09-01

The genomes of most bacteria contain mobile DNA elements that can contribute to undesirable genetic instability in engineered cells. In particular, transposable insertion sequence (IS) elements can rapidly inactivate genes that are important for a designed function. We deleted all six copies of IS 1236 from the genome of the naturally transformable bacterium Acinetobacter baylyi ADP1. The natural competence of ADP1 made it possible to rapidly repair deleterious point mutations that arose during strain construction. In the resulting ADP1-ISx strain, the rates of mutations inactivating a reporter gene were reduced by 7- to 21-fold. This reduction was higher than expected from the incidence of new IS 1236 insertions found during a 300-day mutation accumulation experiment with wild-type ADP1 that was used to estimate spontaneous mutation rates in the strain. The extra improvement appears to be due in part to eliminating large deletions caused by IS 1236 activity, as the point mutation rate was unchanged in ADP1-ISx. Deletion of an error-prone polymerase ( dinP ) and a DNA damage response regulator ( umuD Ab [the umuD gene of A. baylyi ]) from the ADP1-ISx genome did not further reduce mutation rates. Surprisingly, ADP1-ISx exhibited increased transformability. This improvement may be due to less autolysis and aggregation of the engineered cells than of the wild type. Thus, deleting IS elements from the ADP1 genome led to a greater than expected increase in evolutionary reliability and unexpectedly enhanced other key strain properties, as has been observed for other clean-genome bacterial strains. ADP1-ISx is an improved chassis for metabolic engineering and other applications. IMPORTANCE Acinetobacter baylyi ADP1 has been proposed as a next-generation bacterial host for synthetic biology and genome engineering due to its ability to efficiently take up DNA from its environment during normal growth. We deleted transposable elements that are capable of copying themselves

Prevalence of deleterious ATM germline mutations in gastric cancer patients.

Science.gov (United States)

Huang, Dong-Sheng; Tao, Hou-Quan; He, Xu-Jun; Long, Ming; Yu, Sheng; Xia, Ying-Jie; Wei, Zhang; Xiong, Zikai; Jones, Sian; He, Yiping; Yan, Hai; Wang, Xiaoyue

2015-12-01

Besides CDH1, few hereditary gastric cancer predisposition genes have been previously reported. In this study, we discovered two germline ATM mutations (p.Y1203fs and p.N1223S) in a Chinese family with a history of gastric cancer by screening 83 cancer susceptibility genes. Using a published exome sequencing dataset, we found deleterious germline mutations of ATM in 2.7% of 335 gastric cancer patients of different ethnic origins. The frequency of deleterious ATM mutations in gastric cancer patients is significantly higher than that in general population (p=0.0000435), suggesting an association of ATM mutations with gastric cancer predisposition. We also observed biallelic inactivation of ATM in tumors of two gastric cancer patients. Further evaluation of ATM mutations in hereditary gastric cancer will facilitate genetic testing and risk assessment.

Co-inheritance of α0 -thalassemia elevates Hb A2 level in homozygous Hb E: Diagnostic implications.

Science.gov (United States)

Singha, K; Srivorakun, H; Fucharoen, G; Fucharoen, S

2017-10-01

Differentiation of homozygous hemoglobin (Hb) E with and without α 0 -thalassemia is subtle on routine hematological ground. We examined in a large cohort of homozygous Hb E if the level of Hb A 2 is helpful. A total of 592 subjects with homozygous Hb E were recruited from ongoing thalassemia screening program. Additionally, five couples at risk of having fetuses with Hb Bart's hydrops fetalis who were homozygous Hb E were also investigated. Hb analysis was performed using capillary electrophoresis system. Globin genotypes were defined by DNA analysis. Subjects were classified into four groups including pure homozygous Hb E (n=532), homozygous Hb E/α 0 -thalassemia (n=48), Hb Constant Spring EE Bart's disease (n=8), and Hb EE Bart's disease (n=4). The levels of Hb A 2 were found, respectively, to be 4.97±0.69, 6.64±1.02, 4.86±0.87, and 7.60±1.04%. Among five couples at risk, α 0 -thalassemia was identified in three subjects with Hb A 2 >6.0%. Increased Hb A 2 level is a useful marker for differentiation of homozygous Hb E with and without α 0 -thalassemia. This should lead to a significant reduction in number of referral cases of homozygous Hb E for molecular testing of α 0 -thalassemia in routine practice. © 2017 John Wiley & Sons Ltd.

Expanding the phenotypic and mutational spectrum in microcephalic osteodysplastic primordial dwarfism type I.

Science.gov (United States)

Abdel-Salam, Ghada M H; Abdel-Hamid, Mohamed S; Issa, Mahmoud; Magdy, Ahmed; El-Kotoury, Ahmed; Amr, Khalda

2012-06-01

Mutations in the RNU4ATAC gene cause microcephalic osteodysplastic primordial dwarfism type I. It encodes U4atac, a small nuclear RNA that is a component of the minor spliceosome. Six distinct mutations in 30 patients diagnosed as microcephalic osteodysplastic primordial dwarfism type I have been described. We report on three additional patients from two unrelated families presenting with a milder phenotype of microcephalic osteodysplastic primordial dwarfism type I and metopic synostosis. Patient 1 had two novel heterozygous mutations in the 3' prime stem-loop, g.66G > C and g.124G > A while Patients 2 and 3 had a homozygous mutation g.55G > A in the 5' prime stem-loop. Although they manifested the known spectrum of clinical features of microcephalic osteodysplastic primordial dwarfism type I, they lacked evidence of severe developmental delay and neurological symptoms. These findings expand the mutational and phenotypic spectrum of this syndrome. Copyright © 2012 Wiley Periodicals, Inc.

A postnatal role for embryonic myosin revealed by MYH3 mutations that alter TGFbeta signaling and cause autosomal dominant spondylocarpotarsal synostosis

NARCIS (Netherlands)

Zieba, J.; Zhang, W.; Chong, J.X.; Forlenza, K.N.; Martin, J.H.; Heard, K.; Grange, D.K.; Butler, M.G.; Kleefstra, T.; Lachman, R.S.; Nickerson, D.; Regnier, M.; Cohn, D.H.; Bamshad, M.; Krakow, D.

2017-01-01

Spondylocarpotarsal synostosis (SCT) is a skeletal disorder characterized by progressive vertebral, carpal and tarsal fusions, and mild short stature. The majority of affected individuals have an autosomal recessive form of SCT and are homozygous or compound heterozygous for nonsense mutations in

Dosage effect of a Phex mutation in a murine model of X-linked hypophosphatemia

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Ichikawa, Shoji; Gray, Amie K.; Bikorimana, Emmanuel; Econs, Michael J.

2013-01-01

X-linked hypophosphatemia (XLH) is caused by mutations in the PHEX gene, which increase circulating levels of the phosphaturic hormone, fibroblast growth factor 23 (FGF23). Since XLH is a dominant disease, one mutant allele is sufficient for manifestation of the disease. However, dosage effect of a PHEX mutation in XLH is not completely understood. To examine the effect of Phex genotypes, we compared serum biochemistries and skeletal measures between all five possible genotypes of a new murine model of XLH (PhexK496X or PhexJrt). Compared to sex-matched littermate controls, all Phex mutant mice had hypophosphatemia, mild hypocalcemia, and increased parathyroid hormone and alkaline phosphatase levels. Furthermore, mutant mice had markedly elevated serum Fgf23 levels due to increased Fgf23 expression and reduced cleavage of Fgf23. Although females with a homozygous Phex mutation were slightly more hypocalcemic and hypophosphatemic than heterozygous females, the two groups had comparable intact Fgf23 levels. Similarly, there was no difference in intact Fgf23 or phosphorus concentrations between hemizygous males and heterozygous females. Compared to heterozygous females, homozygous counterparts were significantly smaller and had shorter femurs with reduced bone mineral density, suggesting the existence of dosage effect in the skeletal phenotype of XLH. However, overall phenotypic trends in regards to mineral ion homeostasis were mostly unaffected by the presence of one or two mutant Phex allele(s). The lack of gene dosage effect on circulating Fgf23 (and thus, phosphorus) levels suggests that a Phex mutation may create the lower set point for extracellular phosphate concentrations. PMID:23700148

A novel mutation in the albumin gene (c.1A>C) resulting in analbuminemia.

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Caridi, Gianluca; Dagnino, Monica; Lugani, Francesca; Shalev, Stavit A; Campagnoli, Monica; Galliano, Monica; Spiegel, Ronen; Minchiotti, Lorenzo

2013-01-01

Analbuminemia (OMIM # 103600) is a rare autosomal recessive disorder manifested by the absence or severe reduction of circulating serum albumin in homozygous or compound heterozygous subjects. The trait is caused by a variety of mutations within the albumin gene. We report here the clinical and molecular characterisation of two new cases of congenital analbuminemia diagnosed in two members of the Druze population living in a Galilean village (Northern Israel) on the basis of their low level of circulating albumin. The albumin gene was screened by single-strand conformation polymorphism and heteroduplex analysis, and the mutated region was submitted to DNA sequencing. Both the analbuminemic subjects resulted homozygous for a previously unreported c.1 A>C transversion, for which we suggest the name Afula from the hospital where the two cases were investigated. This mutation causes the loss of the primary start codon ATG for Met1, which is replaced by a - then untranslated - triplet CTG for Leu. (p.Met1Leu). The use of an alternative downstream ATG codon would probably give rise to a completely aberrant polypeptide chain, leading to a misrouted intracellular transport and a premature degradation. The discovery of this new ALB mutation, probably inherited from a common ancestor, sheds light on the molecular mechanism underlying the analbuminemic trait and may serve in the development of a rapid genetic test for the identification of a-symptomatic heterozygous carriers in the Druze population in the Galilee. © 2012 The Authors. European Journal of Clinical Investigation © 2012 Stichting European Society for Clinical Investigation Journal Foundation.

RNA-based mutation analysis identifies an unusual MSH6 splicing defect and circumvents PMS2 pseudogene interference.

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Etzler, J; Peyrl, A; Zatkova, A; Schildhaus, H-U; Ficek, A; Merkelbach-Bruse, S; Kratz, C P; Attarbaschi, A; Hainfellner, J A; Yao, S; Messiaen, L; Slavc, I; Wimmer, K

2008-02-01

Heterozygous germline mutations in one of the mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2 cause hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome, a dominantly inherited cancer susceptibility syndrome. Recent reports provide evidence for a novel recessively inherited cancer syndrome with constitutive MMR deficiency due to biallelic germline mutations in one of the MMR genes. MMR-deficiency (MMR-D) syndrome is characterized by childhood brain tumors, hematological and/or gastrointestinal malignancies, and signs of neurofibromatosis type 1 (NF1). We established an RNA-based mutation detection assay for the four MMR genes, since 1) a number of splicing defects may escape detection by the analysis of genomic DNA, and 2) DNA-based mutation detection in the PMS2 gene is severely hampered by the presence of multiple highly similar pseudogenes, including PMS2CL. Using this assay, which is based on direct cDNA sequencing of RT-PCR products, we investigated two families with children suspected to suffer from MMR-D syndrome. We identified a homozygous complex MSH6 splicing alteration in the index patients of the first family and a novel homozygous PMS2 mutation (c.182delA) in the index patient of the second family. Furthermore, we demonstrate, by the analysis of a PMS2/PMS2CL "hybrid" allele carrier, that RNA-based PMS2 testing effectively avoids the caveats of genomic DNA amplification approaches; i.e., pseudogene coamplification as well as allelic dropout, and will, thus, allow more sensitive mutation analysis in MMR deficiency and in HNPCC patients with PMS2 defects. (c) 2007 Wiley-Liss, Inc.

Arrestin gene mutations in autosomal recessive retinitis pigmentosa.

Science.gov (United States)

Nakazawa, M; Wada, Y; Tamai, M

1998-04-01

To assess the clinical and molecular genetic studies of patients with autosomal recessive retinitis pigmentosa associated with a mutation in the arrestin gene. Results of molecular genetic screening and case reports with DNA analysis and clinical features. University medical center. One hundred twenty anamnestically unrelated patients with autosomal recessive retinitis pigmentosa. DNA analysis was performed by single strand conformation polymorphism followed by nucleotide sequencing to search for a mutation in exon 11 of the arrestin gene. Clinical features were characterized by visual acuity slitlamp biomicroscopy, fundus examinations, fluorescein angiography, kinetic visual field testing, and electroretinography. We identified 3 unrelated patients with retinitis pigmentosa associated with a homozygous 1-base-pair deletion mutation in codon 309 of the arrestin gene designated as 1147delA. All 3 patients showed pigmentary retinal degeneration in the midperipheral area with or without macular involvement. Patient 1 had a sibling with Oguchi disease associated with the same mutation. Patient 2 demonstrated pigmentary retinal degeneration associated with a golden-yellow reflex in the peripheral fundus. Patients 1 and 3 showed features of retinitis pigmentosa without the golden-yellow fundus reflex. Although the arrestin 1147delA has been known as a frequent cause of Oguchi disease, this mutation also may be related to the pathogenesis of autosomal recessive retinitis pigmentosa. This phenomenon may provide evidence of variable expressivity of the mutation in the arrestin gene.