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1.
Gene ; 714: 143990, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31326550

RESUMO

BACKGROUND: Progressive cardiac conduction defect (PCCD), also known as Lenegre-Lev disease, is one of the most common heart conduction abnormalities. Previous studies have screened for known mutation sites that cause heart block in a 68-person family with a history of PCCD, revealed no mutations. OBJECTIVE: To screen pathogenic genes of the PCCD family and to study the function of the gene mutations related to heart block diseases. METHODS: Whole exome sequencing (WES) was performed on two PCCD patients and one non-PCCD family member to find the related pathogenic gene. After family co-segregation and preliminary functional analysis, we identified the mutant gene CLCA2. To study the function of this gene, we constructed mutant-gene mice using CRISPR-Cas9 technology, and electrocardiogram monitoring was performed after genotype verification. RESULTS: The CLCA2 c.G1725T mutation was identified and co-segregated with the phenotype. The analysis showed that the CLCA2 c.G1725T mutation is harmful and mainly affects protein glycosylation. Immunofluorescence staining revealed that CLCA2 was highly expressed in the sinoatrial node (SAN) tissues. Electrocardiogram monitoring of the mice revealed that CLCA2 point mutations induced mild conduction block and ectopic pacemakers. CONCLUSION: Our findings indicate that a novel heterozygous missense mutation c.G1725T of the CLCA2 gene may be associated with heart block disease and the mutation in this gene may lead to sinus node lesions and conduction blocking.


Assuntos
Canais de Cloreto/genética , Bloqueio Cardíaco/genética , Mutação de Sentido Incorreto/genética , Sequência de Aminoácidos , Animais , Eletrocardiografia/métodos , Feminino , Heterozigoto , Humanos , Masculino , Camundongos , Linhagem , Fenótipo , Mutação Puntual/genética , Nó Sinoatrial/patologia
2.
Nat Commun ; 10(1): 2569, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31189880

RESUMO

Synonymous mutations have been viewed as silent mutations, since they only affect the DNA and mRNA, but not the amino acid sequence of the resulting protein. Nonetheless, recent studies suggest their significant impact on splicing, RNA stability, RNA folding, translation or co-translational protein folding. Hence, we compile 659194 synonymous mutations found in human cancer and characterize their properties. We provide the user-friendly, comprehensive resource for synonymous mutations in cancer, SynMICdb ( http://SynMICdb.dkfz.de ), which also contains orthogonal information about gene annotation, recurrence, mutation loads, cancer association, conservation, alternative events, impact on mRNA structure and a SynMICdb score. Notably, synonymous and missense mutations are depleted at the 5'-end of the coding sequence as well as at the ends of internal exons independent of mutational signatures. For patient-derived synonymous mutations in the oncogene KRAS, we indicate that single point mutations can have a relevant impact on expression as well as on mRNA secondary structure.


Assuntos
Bases de Dados de Ácidos Nucleicos , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias/genética , Mutação Silenciosa/genética , Conjuntos de Dados como Assunto , Humanos , Mutação de Sentido Incorreto/genética , Mutação Puntual/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Dobramento de RNA/genética , Processamento de RNA/genética , RNA Mensageiro/química , RNA Mensageiro/genética
3.
Genet Test Mol Biomarkers ; 23(5): 310-315, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30932712

RESUMO

Objective:Heterozygous pathogenic variants in the COL2A1 gene result in several clinical features including impaired skeletal growth, ocular and otolaryngological abnormalities. Missense mutations in the triple helical region of the COL2A1 protein have been associated with lethal spondyloepiphyseal dysplasia (SED). In this study, we aimed to identify the underlying cause of a case of SED congenita (SEDC) in a 27-month-old child. Materials and Methods: A patient who was diagnosed initially with osteochondrodysplasia underwent a detailed clinical and radiological examination to obtain a conclusive diagnosis. The patient did not show any clinical features of hypochondrogenesis. Whole exome sequencing of the COL2A1 gene was carried out to identify the underlying genetic cause of the disorder. Results: Variant annotation and filtration detected a heterozygous missense mutation c.1357G>A (p.G453S) in the exon 21 of the COL2A1 gene of the proband which was confirmed by Sanger sequencing. Neither parent carried the mvariant suggesting this was a new mutation. Conclusion: The COL2A1 mutation (c.1357G>A), identified in this case, results in more mild phenotype than other missense mutations in exon 21 which are known to cause lethal hypochondrogenesis. We showed, for the first time, that a missense mutation (p.G453S) in the triple helical region of the alpha 1 (II) chain of the COL2A1 protein underlies SEDC and is not always lethal.


Assuntos
Colágeno Tipo II/genética , Osteocondrodisplasias/congênito , Colágeno Tipo II/fisiologia , Feminino , Heterozigoto , Humanos , Lactente , Mutação , Mutação de Sentido Incorreto/genética , Osteocondrodisplasias/genética , Osteocondrodisplasias/fisiopatologia , Arábia Saudita , Sequenciamento Completo do Exoma
4.
Nat Cell Biol ; 21(5): 579-591, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30962574

RESUMO

It is well established that ferroptosis is primarily controlled by glutathione peroxidase 4 (GPX4). Surprisingly, we observed that p53 activation modulates ferroptotic responses without apparent effects on GPX4 function. Instead, ALOX12 inactivation diminishes p53-mediated ferroptosis induced by reactive oxygen species stress and abrogates p53-dependent inhibition of tumour growth in xenograft models, suggesting that ALOX12 is critical for p53-mediated ferroptosis. The ALOX12 gene resides on human chromosome 17p13.1, a hotspot of monoallelic deletion in human cancers. Loss of one Alox12 allele is sufficient to accelerate tumorigenesis in Eµ-Myc lymphoma models. Moreover, ALOX12 missense mutations from human cancers abrogate its ability to oxygenate polyunsaturated fatty acids and to induce p53-mediated ferroptosis. Notably, ALOX12 is dispensable for ferroptosis induced by erastin or GPX4 inhibitors; conversely, ACSL4 is required for ferroptosis upon GPX4 inhibition but dispensable for p53-mediated ferroptosis. Thus, our study identifies an ALOX12-mediated, ACSL4-independent ferroptosis pathway that is critical for p53-dependent tumour suppression.


Assuntos
Araquidonato 12-Lipoxigenase/genética , Carcinogênese/genética , Glutationa Peroxidase/genética , Proteína Supressora de Tumor p53/genética , Animais , Apoptose/genética , Linhagem Celular Tumoral , Modelos Animais de Doenças , Glutationa Peroxidase/antagonistas & inibidores , Humanos , Peroxidação de Lipídeos/genética , Linfoma/genética , Linfoma/patologia , Camundongos , Mutação de Sentido Incorreto/genética , Espécies Reativas de Oxigênio , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Cell Mol Biol (Noisy-le-grand) ; 65(3): 84-88, 2019 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-30942159

RESUMO

The aim of this study was to identify the novel missense eya4 mutation which cause autosomal dominant non syndromic hearing loss In a Chinese family. Hearing loss is the most common sensory deficit in humans, but the middle-frequency sensorineural hearing loss (MFSNHL) is rare among hereditary non-syndromic hearing loss, and EYA4 is one of the genes reported to be associated with MFSNHL. A genetic analysis of a Chinese family with autosomal dominant non­syndromic progressive hearing impairment was conducted and assessed. Targeted exome sequencing, conducted using DNA samples of an affected member in this family, revealed a novel heterozygous missense mutation c.1855T>G in exon 20 of EYA4, causing amino-acid (aa) substitution Gly for Trp at a conserved position aa-619. The p.W619G mutation related to hearing loss in this Chinese family was validated by Sanger sequencing. Bioinformatic analysis confirmed the pathogenic effects of this mutation. We identified the novel missense mutation c.1855T>G (p.W619G) in EYA4 causing autosomal dominant non-syndromic hearing impairment in the selected Chinese family.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Genes Dominantes , Perda Auditiva/genética , Mutação de Sentido Incorreto/genética , Transativadores/genética , Adulto , Idoso , Simulação por Computador , Exoma/genética , Família , Feminino , Loci Gênicos , Humanos , Masculino , Pessoa de Meia-Idade , Software
6.
Methods Mol Biol ; 1958: 173-185, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30945219

RESUMO

The ability to predict how mutations affect protein structure, folding, and flexibility can elucidate the molecular mechanisms leading to disruption of supersecondary structures, the emergence of phenotypes, as well guiding rational protein engineering. The advent of fast and accurate computational tools has enabled us to comprehensively explore the landscape of mutation effects on protein structures, prioritizing mutations for rational experimental validation.Here we describe the use of two complementary web-based in silico methods, DUET and DynaMut, developed to infer the effects of mutations on folding, stability, and flexibility and how they can be used to explore and interpret these effects on protein supersecondary structures.


Assuntos
Substituição de Aminoácidos/genética , Biologia Computacional/métodos , Engenharia de Proteínas/métodos , Proteínas/química , Motivos de Aminoácidos , Humanos , Mutação de Sentido Incorreto/genética , Dobramento de Proteína , Estabilidade Proteica , Proteínas/genética
7.
Eur J Endocrinol ; 180(5): 291-309, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30893644

RESUMO

Context Most of the knowledge on the factors involved in human sexual development stems from studies of rare cases with disorders of sex development. Here, we have described a novel 46, XY complete gonadal dysgenesis syndrome caused by homozygous variants in PPP2R3C gene. This gene encodes B″gamma regulatory subunit of the protein phosphatase 2A (PP2A), which is a serine/threonine phosphatase involved in the phospho-regulation processes of most mammalian cell types. PPP2R3C gene is most abundantly expressed in testis in humans, while its function was hitherto unknown. Patients and methods Four girls from four unrelated families with 46, XY complete gonadal dysgenesis were studied using exome or Sanger sequencing of PPP2R3C gene. In total, four patients and their heterozygous parents were investigated for clinical, laboratory, immunohistochemical and molecular characteristics. Results We have identified three different homozygous PPP2R3C variants, c.308T>C (p.L103P), c.578T>C (p.L193S) and c.1049T>C (p.F350S), in four girls with 46, XY complete gonadal dysgenesis. Patients also manifested a unique syndrome of extragonadal anomalies, including typical facial gestalt, low birth weight, myopathy, rod and cone dystrophy, anal atresia, omphalocele, sensorineural hearing loss, dry and scaly skin, skeletal abnormalities, renal agenesis and neuromotor delay. We have shown a decreased SOX9-Phospho protein expression in the dysgenetic gonads of the patients with homozygous PPP2R3C variants suggesting impaired SOX9 signaling in the pathogenesis of gonadal dysgenesis. Heterozygous males presented with abnormal sperm morphology and impaired fertility. Conclusion Our findings suggest that PPP2R3C protein is involved in the ontogeny of multiple organs, especially critical for testis development and spermatogenesis. PPPR3C provides insight into pathophysiology, as well as emerging as a potential therapeutic target for male infertility.


Assuntos
Disgenesia Gonadal 46 XY/genética , Proteína Fosfatase 2/genética , Espermatogênese/genética , Adulto , Sequência de Aminoácidos , Sequência de Bases , Criança , Pré-Escolar , Anormalidades Congênitas/genética , Consanguinidade , Feminino , Disgenesia Gonadal 46 XY/patologia , Homozigoto , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Mutação , Mutação de Sentido Incorreto/genética , Linhagem , Fenótipo , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição SOX9/genética , Síndrome , Testículo/embriologia , Testículo/patologia
8.
Hum Genet ; 138(5): 525-533, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30877375

RESUMO

Amelogenesis imperfecta (AI) refers to a genetically and clinically heterogeneous group of inherited disorders affecting the structure, composition, and quantity of tooth enamel. Both non-syndromic and syndromic forms of AI have been described and several genes affecting various aspects of the enamel physiology have been reported. Genetically modified murine models of various genes have provided insights into the complex regulation of proper amelogenesis. Non-syndromic AI occurs spontaneously also in dogs with known recessive variants in ENAM and SLC24A4 genes. Unlike rodents with a reduced dentition and continuously erupting incisors, canine models are valuable for human AI due to similarity in the dental anatomy including deciduous and permanent teeth. We have performed a series of clinical and genetic analyses to investigate AI in several breeds of dogs and describe here two novel recessive variants in the ENAM and ACP4 genes. A fully segregating missense variant (c.716C>T) in exon 8 of ENAM substitutes a well-conserved proline to leucine, p.(Pro239Leu), resulting in a clinical hypomineralization of teeth. A 1-bp insertion in ACP4 (c.1189dupG) is predicted to lead to a frameshift, p.(Ala397Glyfs), resulting in an abnormal C-terminal part of the protein, and hypoplastic AI. The ENAM variant was specific for Parson Russell Terriers with a carrier frequency of 9%. The ACP4 variant was found in two breeds, Akita and American Akita with a carrier frequency of 22%. These genetic findings establish novel canine models of human AI with a particular interest in the case of the ACP4-deficient model, since ACP4 physiology is poorly characterized in human AI. The affected dogs could also serve as preclinical models for novel treatments while the breeds would benefit from genetic tests devised here for veterinary diagnostics and breeding programs.


Assuntos
Amelogênese Imperfeita/genética , Amelogênese Imperfeita/veterinária , Proteínas do Esmalte Dentário/genética , Esmalte Dentário/fisiopatologia , Fosfatase Ácida Resistente a Tartarato/genética , Animais , Modelos Animais de Doenças , Cães , Mutação da Fase de Leitura/genética , Genótipo , Humanos , Mutação de Sentido Incorreto/genética
9.
BMC Evol Biol ; 19(1): 72, 2019 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-30849938

RESUMO

BACKGROUND: Frizzled family members belong to G-protein coupled receptors and encode proteins accountable for cell signal transduction, cell proliferation and cell death. Members of Frizzled receptor family are considered to have critical roles in causing various forms of cancer, cardiac hypertrophy, familial exudative vitreoretinopathy (FEVR) and schizophrenia. RESULTS: This study investigates the evolutionary and structural aspects of Frizzled receptors, with particular focus on FEVR associated FZD4 gene. The phylogenetic tree topology suggests the diversification of Frizzled receptors at the root of metazoans history. Moreover, comparative structural data reveals that FEVR associated missense mutations in FZD4 effect the common protein region (amino acids 495-537) through a well-known phenomenon called epistasis. This critical protein region is present at the carboxyl-terminal domain and encompasses the K-T/S-XXX-W, a PDZ binding motif and S/T-X-V PDZ recognition motif. CONCLUSION: Taken together these results demonstrate that during the course of evolution, FZD4 has acquired new functions or epistasis via complex patter of gene duplications, sequence divergence and conformational remodeling. In particular, amino acids 495-537 at the C-terminus region of FZD4 protein might be crucial in its normal function and/or pathophysiology. This critical region of FZD4 protein may offer opportunities for the development of novel therapeutics approaches for human retinal vascular disease.


Assuntos
Evolução Molecular , Oftalmopatias Hereditárias/genética , Receptores Frizzled/química , Receptores Frizzled/genética , Doenças Retinianas/genética , Humanos , Proteínas Mutantes/química , Proteínas Mutantes/genética , Mutação de Sentido Incorreto/genética , Filogenia , Domínios Proteicos
10.
Mol Brain ; 12(1): 19, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30866998

RESUMO

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS [MIM 270550]) is an early-onset neurodegenerative disorder caused by mutations in the SACS gene. Over 200 SACS mutations have been identified. Most mutations lead to a complete loss of a sacsin, a large 520 kD protein, although some missense mutations are associated with low levels of sacsin expression. We previously showed that Sacs knock-out mice demonstrate early-onset ataxic phenotype with neurofilament bundling in many neuronal populations. To determine if the preservation of some mutated sacsin protein resulted in the same cellular and behavioral alterations, we generated mice expressing an R272C missense mutation, a homozygote mutation found in some affected patients. Though SacsR272C mice express 21% of wild type brain sacsin and sacsin is found in many neurons, they display similar abnormalities to Sacs knock-out mice, including the development of an ataxic phenotype, reduced Purkinje cell firing rates, and somatodendritic neurofilament bundles in Purkinje cells and other neurons. Together our results support that Sacs missense mutation largely lead to loss of sacsin function.


Assuntos
Ataxia/genética , Ataxia/fisiopatologia , Proteínas de Choque Térmico/genética , Mutação de Sentido Incorreto/genética , Potenciais de Ação , Animais , Sequência de Bases , Encéfalo/metabolismo , Encéfalo/patologia , Dendritos/metabolismo , Marcação de Genes , Proteínas de Choque Térmico/metabolismo , Homozigoto , Humanos , Filamentos Intermediários/metabolismo , Camundongos Endogâmicos C57BL , Atividade Motora , Debilidade Muscular/patologia , Fenótipo , Células de Purkinje/metabolismo , Células de Purkinje/patologia
12.
J Hum Genet ; 64(6): 511-519, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30853710

RESUMO

ORAI1 encodes a calcium channel essential in the store-operated calcium entry mechanism. A previous genetic association study identified a rare in-frame insertion variant of ORAI1 conferring Kawasaki disease (KD). To deepen our understanding of the involvement of rare variants of ORAI1 in KD pathogenesis, we investigated 3812 patients with KD and 2644 healthy individuals for variations in the protein-coding region of ORAI1. By re-sequencing the study participants' DNA, 27 variants with minor allele frequencies (MAFs) < 0.01 that had not been examined in the previous study were identified. Although no significant association with KD was observed either in single-variant analyses or in a collapsing method analysis of the 27 variants, stratification by MAFs, variant types, and predicted deleteriousness revealed that six rare, deleterious, missense variants (MAF < 0.001, CADD C-score ≥ 20) were exclusively present in KD patients, including three refractory cases (OR = ∞, P = 0.046). The six missense variants include p.Gly98Asp, which has been demonstrated to result in gain of function leading to constitutive Ca2+ entry. Conversely, five types of frameshift variants, all identified near the N terminus and assumed to disrupt ORAI1 function, showed an opposite trend of association (OR = 0.35, P = 0.24). These findings support our hypothesis that genetic variations causing the upregulation of the Ca2+/NFAT pathway confer susceptibility to KD. Our findings also provide insights into the usefulness of stratifying the variants based on their MAFs and on the direction of the effects on protein function when conducting association studies using the gene-based collapsing method.


Assuntos
Estudos de Associação Genética , Predisposição Genética para Doença , Síndrome de Linfonodos Mucocutâneos/genética , Proteína ORAI1/genética , Cálcio/metabolismo , Pré-Escolar , Feminino , Mutação com Ganho de Função/genética , Frequência do Gene , Humanos , Lactente , Masculino , Síndrome de Linfonodos Mucocutâneos/patologia , Mutação de Sentido Incorreto/genética , Polimorfismo de Nucleotídeo Único/genética
13.
J Hum Genet ; 64(6): 561-572, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30858506

RESUMO

Variants have been identified in the embryonic ectoderm development (EED) gene in seven patients with syndromic overgrowth similar to that observed in Weaver syndrome. Here, we present three additional patients with missense variants in the EED gene. All the missense variants reported to date (including the three presented here) have localized to one of seven WD40 domains of the EED protein, which are necessary for interaction with enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). In addition, among the seven patients reported in the literature and the three new patients presented here, all of the reported pathogenic variants except one occurred at one of four amino acid residues in the EED protein. The recurrence of pathogenic variation at these loci suggests that these residues are functionally important (mutation hotspots). In silico modeling and calculations of the free energy changes resulting from these variants suggested that they not only destabilize the EED protein structure but also adversely affect interactions between EED, EZH2, and/or H3K27me3. These cases help demonstrate the mechanism(s) by which apparently deleterious variants in the EED gene might cause overgrowth and lend further support that amino acid residues in the WD40 domain region may be mutation hotspots.


Assuntos
Anormalidades Múltiplas/genética , Hipotireoidismo Congênito/genética , Anormalidades Craniofaciais/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Deformidades Congênitas da Mão/genética , Histona-Lisina N-Metiltransferase/genética , Complexo Repressor Polycomb 2/genética , Anormalidades Múltiplas/etiologia , Anormalidades Múltiplas/fisiopatologia , Adolescente , Criança , Simulação por Computador , Hipotireoidismo Congênito/etiologia , Hipotireoidismo Congênito/fisiopatologia , Anormalidades Craniofaciais/etiologia , Anormalidades Craniofaciais/fisiopatologia , Proteína Potenciadora do Homólogo 2 de Zeste/química , Feminino , Deformidades Congênitas da Mão/etiologia , Deformidades Congênitas da Mão/fisiopatologia , Histona-Lisina N-Metiltransferase/química , Humanos , Masculino , Simulação de Dinâmica Molecular , Taxa de Mutação , Mutação de Sentido Incorreto/genética , Complexo Repressor Polycomb 2/química , Conformação Proteica , Repetições WD40/genética , Sequenciamento Completo do Exoma
15.
Biomed Pharmacother ; 111: 983-992, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30841478

RESUMO

Genetic polymorphisms in cytochrome P450 (CYP) or UDP-glucuronosyltransferase (UGT) genes can lead to changes in endocrine regulation or drug metabolism. Based on the recently published allele frequency data of the Exome Aggregation Consortium (ExAC), we extracted all common SNP variants that lead to missense mutations in CYPs and UGTs or in their helping proteins CPR, AdR, Adx, and UGDH. With a total of 737 alleles from 83 genes we provide the most comprehensive overview of missense variation distributions in drug metabolizing enzymes published to date. In all variants the most common allele was always considered to be the wild-type (WT), even if it was not identical to the *1-allele and/or the reference standard sequence of the RefSeq project. Surprisingly, in 15 cases (AdR, CYP2A7, CYP2C19, CYP2D6, CYP4A22, CYP4F11, CYP4F12, CYP4V2, CYP8B1, CYP20A1, UGT1A3, UGT1A7, UGT2A3, UGT2B7, and UGT2B15), the WT protein sequences were found to differ from reference standard sequences in up to four amino acids. We expect that these findings will have an impact on the definition of reference sequence standards for these genes, on the corresponding naming of alleles, and on the definition of reference standard activities.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Glucuronosiltransferase/genética , Mutação de Sentido Incorreto/genética , Alelos , Aminoácidos/genética , Exoma/genética , Frequência do Gene/genética , Humanos , Polimorfismo de Nucleotídeo Único/genética
16.
PLoS Genet ; 15(3): e1008049, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30925164

RESUMO

The BARD1 protein, which heterodimerizes with BRCA1, is encoded by a known breast cancer susceptibility gene. While several BARD1 variants have been identified as pathogenic, many more missense variants exist that do not occur frequently enough to assign a clinical risk. In this paper, whole exome sequencing of over 10,000 cancer samples from 33 cancer types identified from somatic mutations and loss of heterozygosity in tumors 76 potentially cancer-associated BARD1 missense and truncation variants. These variants were tested in a functional assay for homology-directed repair (HDR), as HDR deficiencies have been shown to correlate with clinical pathogenicity for BRCA1 variants. From these 76 variants, 4 in the ankyrin repeat domain and 5 in the BRCT domain were found to be non-functional in HDR. Two known benign variants were found to be functional in HDR, and three known pathogenic variants were non-functional, supporting the notion that the HDR assay can be used to predict the clinical risk of BARD1 variants. The identification of HDR-deficient variants in the ankyrin repeat domain indicates there are DNA repair functions associated with this domain that have not been closely examined. In order to examine whether BARD1-associated loss of HDR function results in DNA damage sensitivity, cells expressing non-functional BARD1 variants were treated with ionizing radiation or cisplatin. These cells were found to be more sensitive to DNA damage, and variations in the residual HDR function of non-functional variants did not correlate with variations in sensitivity. These findings improve the understanding of BARD1 functional domains in DNA repair and support that this functional assay is useful for predicting the cancer association of BARD1 variants.


Assuntos
Neoplasias/genética , Reparo de DNA por Recombinação/genética , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/genética , Animais , Proteína BRCA1/metabolismo , Gatos , Dano ao DNA , Reparo do DNA/genética , Cães , Feminino , Humanos , Camundongos , Mutação de Sentido Incorreto/genética , Alinhamento de Sequência , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/fisiologia , Sequenciamento Completo do Exoma
17.
J Appl Genet ; 60(2): 151-162, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30706430

RESUMO

Autosomal recessive primary microcephaly (MCPH) is a group of rare neurodevelopmental diseases with severe microcephaly at birth. One type of the disorder, MCPH2, is caused by biallelic mutations in the WDR62 gene, which encodes the WD repeat-containing protein 62. Patients with WDR62 mutation may have a wide range of malformations of cortical development in addition to congenital microcephaly. We describe two patients, a boy and a girl, with severe congenital microcephaly, global developmental delay, epilepsy, and failure to thrive. MRI showed hemispherical asymmetry, diffuse pachygyria, thick gray matter, indistinct gray-white matter junction, and corpus callosum and white matter hypoplasia. Whole exome sequencing revealed the same novel homozygous missense mutation, c.668T>C, p.Phe223Ser in exon 6 of the WDR62 gene. The healthy parents were heterozygous for this mutation. The mutation affects a highly conserved region in one of the WD repeats of the WDR62 protein. Haplotype analysis showed genetic relatedness between the families of the patients. Our findings expand the spectrum of mutations randomly distributed in the WDR62 gene. A review is also provided of the brain malformations described in WDR62 mutations in association with congenital microcephaly.


Assuntos
Deficiências do Desenvolvimento/genética , Microcefalia/genética , Proteínas do Tecido Nervoso/genética , Deficiências do Desenvolvimento/diagnóstico por imagem , Deficiências do Desenvolvimento/fisiopatologia , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Haplótipos , Homozigoto , Humanos , Masculino , Microcefalia/diagnóstico por imagem , Microcefalia/fisiopatologia , Mutação de Sentido Incorreto/genética , Linhagem , Substância Branca/diagnóstico por imagem , Substância Branca/patologia
18.
Int J Mol Sci ; 20(4)2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30769939

RESUMO

The NOD2 gene, involved in innate immune responses to bacterial peptidoglycan, has been found to be closely associated with Crohn's Disease (CD), with an Odds Ratio ranging from 3⁻36. Families with three or more CD-affected members were related to a high frequency of NOD2 gene variations, such as R702W, G908R, and 1007fs, and were reported in the EPIMAD Registry. However, some rare CD multiplex families were described without identification of common NOD2 linked-to-disease variations. In order to identify new genetic variation(s) closely linked with CD, whole exome sequencing was performed on available subjects, comprising four patients in two generations affected with Crohn's disease without R702W and G908R variation and three unaffected related subjects. A rare and, not yet, reported missense variation of the NOD2 gene, N1010K, was detected and co-segregated across affected patients. In silico evaluation and modelling highlighted evidence for an adverse effect of the N1010K variation with regard to CD. Moreover, cumulative characterization of N1010K and 1007fs as a compound heterozygous state in two, more severe CD family members strongly suggests that N1010K could well be a new risk factor involved in Crohn's disease genetic susceptibility.


Assuntos
Doença de Crohn/genética , Predisposição Genética para Doença , Imunidade Inata/genética , Proteína Adaptadora de Sinalização NOD2/genética , Adolescente , Adulto , Alelos , Criança , Doença de Crohn/imunologia , Doença de Crohn/patologia , Feminino , Estudos de Associação Genética , Genótipo , Heterozigoto , Humanos , Masculino , Mutação , Mutação de Sentido Incorreto/genética , Proteína Adaptadora de Sinalização NOD2/química , Proteína Adaptadora de Sinalização NOD2/imunologia , Peptidoglicano/imunologia , Polimorfismo de Nucleotídeo Único , Conformação Proteica , Sequenciamento Completo do Exoma
19.
Hum Genet ; 138(5): 515-524, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30715562

RESUMO

The dog provides a large animal model of familial dilated cardiomyopathy for the study of important aspects of this common familial cardiovascular disease. We have previously demonstrated a form of canine dilated cardiomyopathy in the Doberman pinscher breed that is inherited as an autosomal dominant trait and is associated with a splice site variant in the pyruvate dehydrogenase kinase 4 (PDK4) gene, however, genetic heterogeneity exists in this species as well and not all affected dogs have the PDK4 variant. Whole genome sequencing of a family of Doberman pinchers with dilated cardiomyopathy and sudden cardiac death without the PDK4 variant was performed. A pathologic missense variant in the titin gene located in an immunoglobulin-like domain in the I-band spanning region of the molecule was identified and was highly associated with the disease (p < 0.0001). We demonstrate here the identification of a variant in the titin gene highly associated with the disease in this spontaneous canine model of dilated cardiomyopathy. This large animal model of familial dilated cardiomyopathy shares many similarities with the human disease including mode of inheritance, clinical presentation, genetic heterogeneity and a pathologic variant in the titin gene. The dog is an excellent model to improve our understanding of the genotypic phenotypic relationships, penetrance, expression and the pathophysiology of variants in the titin gene.


Assuntos
Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/veterinária , Conectina/genética , Morte Súbita Cardíaca/etiologia , Proteínas Quinases/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Morte Súbita Cardíaca/veterinária , Modelos Animais de Doenças , Cães , Feminino , Predisposição Genética para Doença/genética , Masculino , Mutação de Sentido Incorreto/genética , Sequenciamento Completo do Genoma
20.
Orphanet J Rare Dis ; 14(1): 29, 2019 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-30732632

RESUMO

BACKGROUND: The RASopathies are a class of developmental disorders caused by germline mutations in the RAS-mitogen-activated protein kinase (MAPK) pathway. Hypertrophic cardiomyopathy (HCM) has been frequently described in children with RASopathy, but only a minority of patients have received formal genotyping. The purpose of this study was to evaluate the genetic basis and clinical outcome of pediatric patients with RASopathy-associated HCM. METHODS: We retrospectively reviewed the mutation spectrum and clinical outcome of all the patients with RASopathy derived from 168 pediatric HCM cases referred to our institution between January 2012 and July 2018. RESULTS: A heterozygous missense mutation in one of known RASopathy genes was identified in 46 unrelated children with HCM. Mutations in the PTPN11 gene were the most prevalent (19/46); this was followed by mutations in RAF1 (11/46), KRAS (5/46), RIT1 (4/46), BRAF (3/46), SOS1 (2/46), HRAS (1/46), and SHOC2 (1/46). Moreover, two compound heterozygous missense mutations in the LZTR1 gene were identified in one patient with the Noonan syndrome phenotype and HCM. The median age at the diagnosis of HCM was 3.0 months (range 0 months to 8.1 years). Twenty-one of the patients had significant left ventricular outflow tract obstruction and 32 had concomitant congenital heart disease. Three patients with a mutation in exon 13 of the PTPN11 gene died of cardiac failure at the ages of 3.0, 3.5, and 6.0 months. The remaining 44 patients were alive after an average follow-up time of 3.9 years (0.5 to 17.1 years, median 2.9 years) from the initial diagnosis of HCM, including 5 patients with spontaneous regression of their cardiac hypertrophy. CONCLUSIONS: RASopathy-associated HCM is a heterogeneous genetic condition characterized by early-onset cardiac hypertrophy and a high prevalence of co-existing congenital heart disease, which is most frequently related to specific mutations in the PTPN11 gene. Rapidly progressive HCM, resulting in an early death, is uncommon in RASopathy patients except those with specific mutations in exon 13 of the PTPN11 gene.


Assuntos
Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/patologia , Proteínas Quinases Ativadas por Mitógeno/genética , Criança , Pré-Escolar , Estudos de Coortes , Éxons/genética , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação de Sentido Incorreto/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Estudos Retrospectivos , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
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