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1.
Am J Hum Genet ; 104(6): 1210-1222, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31079897

RESUMO

We delineate a KMT2E-related neurodevelopmental disorder on the basis of 38 individuals in 36 families. This study includes 31 distinct heterozygous variants in KMT2E (28 ascertained from Matchmaker Exchange and three previously reported), and four individuals with chromosome 7q22.2-22.23 microdeletions encompassing KMT2E (one previously reported). Almost all variants occurred de novo, and most were truncating. Most affected individuals with protein-truncating variants presented with mild intellectual disability. One-quarter of individuals met criteria for autism. Additional common features include macrocephaly, hypotonia, functional gastrointestinal abnormalities, and a subtle facial gestalt. Epilepsy was present in about one-fifth of individuals with truncating variants and was responsive to treatment with anti-epileptic medications in almost all. More than 70% of the individuals were male, and expressivity was variable by sex; epilepsy was more common in females and autism more common in males. The four individuals with microdeletions encompassing KMT2E generally presented similarly to those with truncating variants, but the degree of developmental delay was greater. The group of four individuals with missense variants in KMT2E presented with the most severe developmental delays. Epilepsy was present in all individuals with missense variants, often manifesting as treatment-resistant infantile epileptic encephalopathy. Microcephaly was also common in this group. Haploinsufficiency versus gain-of-function or dominant-negative effects specific to these missense variants in KMT2E might explain this divergence in phenotype, but requires independent validation. Disruptive variants in KMT2E are an under-recognized cause of neurodevelopmental abnormalities.

2.
Am J Hum Genet ; 102(6): 1104-1114, 2018 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-29861107

RESUMO

Transient neonatal hyperparathyroidism (TNHP) is etiologically a heterogeneous condition. One of the etiologies is an insufficient maternal-fetal calcium transport through the placenta. We report six subjects with homozygous and/or compound-heterozygous mutations in the gene encoding the transient receptor potential cation channel, subfamily V, member 6 (TRPV6), an epithelial Ca2+-selective channel associated with this condition. Exome sequencing on two neonates with skeletal findings consistent with neonatal hyperparathyroidism identified homozygous frameshift mutations before the first transmembrane domain in a subject born to first-cousins parents of Pakistani descent as well as compound-heterozygous mutations (a combination of a frameshift mutation and an intronic mutation that alters mRNA splicing) in an individual born to a non-consanguineous couple of African descent. Subsequently, targeted mutation analysis of TRPV6 performed on four other individuals (born to non-consanguineous Japanese parents) with similar X-rays findings identified compound-heterozygous mutations. The skeletal findings improved or resolved in most subjects during the first few months of life. We identified three missense variants (at the outer edges of the second and third transmembrane domains) that alter the localization of the TRPV6: one recurrent variant at the S2-S3 loop and two recurrent variants (in the fourth ankyrin repeat domain) that impair TRPV6 stability. Compound heterozygous loss-of-function mutations for the pathogenic frameshift allele and the allele with an intronic c.607+5G>A mutation resulted in the most severe phenotype. These results suggest that TNHP is an autosomal-recessive disease caused by TRPV6 mutations that affect maternal-fetal calcium transport.

4.
Genet Med ; 19(5): 575-582, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27811861

RESUMO

PURPOSE: While the diagnostic success of genomic sequencing expands, the complexity of this testing should not be overlooked. Numerous laboratory processes are required to support the identification, interpretation, and reporting of clinically significant variants. This study aimed to examine the workflow and reporting procedures among US laboratories to highlight shared practices and identify areas in need of standardization. METHODS: Surveys and follow-up interviews were conducted with laboratories offering exome and/or genome sequencing to support a research program or for routine clinical services. The 73-item survey elicited multiple choice and free-text responses that were later clarified with phone interviews. RESULTS: Twenty-one laboratories participated. Practices highly concordant across all groups included consent documentation, multiperson case review, and enabling patient opt-out of incidental or secondary findings analysis. Noted divergence included use of phenotypic data to inform case analysis and interpretation and reporting of case-specific quality metrics and methods. Few laboratory policies detailed procedures for data reanalysis, data sharing, or patient access to data. CONCLUSION: This study provides an overview of practices and policies of experienced exome and genome sequencing laboratories. The results enable broader consideration of which practices are becoming standard approaches, where divergence remains, and areas of development in best practice guidelines that may be helpful.Genet Med advance online publication 03 Novemeber 2016.


Assuntos
Testes Genéticos/métodos , Laboratórios/normas , Análise de Sequência de DNA/métodos , Revelação , Testes Genéticos/normas , Humanos , Achados Incidentais , Disseminação de Informação , Laboratórios/ética , Guias de Prática Clínica como Assunto , Relatório de Pesquisa , Tamanho da Amostra , Análise de Sequência de DNA/normas , Inquéritos e Questionários
5.
Am J Hum Genet ; 99(4): 991-999, 2016 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-27693232

RESUMO

The ASXL genes (ASXL1, ASXL2, and ASXL3) participate in body patterning during embryogenesis and encode proteins involved in epigenetic regulation and assembly of transcription factors to specific genomic loci. Germline de novo truncating variants in ASXL1 and ASXL3 have been respectively implicated in causing Bohring-Opitz and Bainbridge-Ropers syndromes, which result in overlapping features of severe intellectual disability and dysmorphic features. ASXL2 has not yet been associated with a human Mendelian disorder. In this study, we performed whole-exome sequencing in six unrelated probands with developmental delay, macrocephaly, and dysmorphic features. All six had de novo truncating variants in ASXL2. A careful review enabled the recognition of a specific phenotype consisting of macrocephaly, prominent eyes, arched eyebrows, hypertelorism, a glabellar nevus flammeus, neonatal feeding difficulties, hypotonia, and developmental disabilities. Although overlapping features with Bohring-Opitz and Bainbridge-Ropers syndromes exist, features that distinguish the ASXL2-associated condition from ASXL1- and ASXL3-related disorders are macrocephaly, absence of growth retardation, and more variability in the degree of intellectual disabilities. We were also able to demonstrate with mRNA studies that these variants are likely to exert a dominant-negative effect, given that both alleles are expressed in blood and the mutated ASXL2 transcripts escape nonsense-mediated decay. In conclusion, de novo truncating variants in ASXL2 underlie a neurodevelopmental syndrome with a clinically recognizable phenotype. This report expands the germline disorders that are linked to the ASXL genes.


Assuntos
Fenótipo , Proteínas Repressoras/genética , Criança , Pré-Escolar , Deficiências do Desenvolvimento/genética , Exoma/genética , Sobrancelhas/anormalidades , Humanos , Hipertelorismo/genética , Lactente , Recém-Nascido , Masculino , Megalencefalia/genética , Hipotonia Muscular/genética , RNA Mensageiro/metabolismo , Síndrome
6.
Am J Hum Genet ; 99(4): 831-845, 2016 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-27640307

RESUMO

ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane protein implicated in mitochondrial dynamics, nucleoid organization, protein translation, cell growth, and cholesterol metabolism. We identified a recurrent de novo ATAD3A c.1582C>T (p.Arg528Trp) variant by whole-exome sequencing (WES) in five unrelated individuals with a core phenotype of global developmental delay, hypotonia, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. We also describe two families with biallelic variants in ATAD3A, including a homozygous variant in two siblings, and biallelic ATAD3A deletions mediated by nonallelic homologous recombination (NAHR) between ATAD3A and gene family members ATAD3B and ATAD3C. Tissue-specific overexpression of borR534W, the Drosophila mutation homologous to the human c.1582C>T (p.Arg528Trp) variant, resulted in a dramatic decrease in mitochondrial content, aberrant mitochondrial morphology, and increased autophagy. Homozygous null bor larvae showed a significant decrease of mitochondria, while overexpression of borWT resulted in larger, elongated mitochondria. Finally, fibroblasts of an affected individual exhibited increased mitophagy. We conclude that the p.Arg528Trp variant functions through a dominant-negative mechanism that results in small mitochondria that trigger mitophagy, resulting in a reduction in mitochondrial content. ATAD3A variation represents an additional link between mitochondrial dynamics and recognizable neurological syndromes, as seen with MFN2, OPA1, DNM1L, and STAT2 mutations.


Assuntos
Adenosina Trifosfatases/genética , Alelos , Proteínas de Membrana/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Proteínas Mitocondriais/genética , Mutação , Doenças do Sistema Nervoso/genética , ATPases Associadas a Diversas Atividades Celulares , Adulto , Animais , Axônios/patologia , Cardiomiopatias/genética , Criança , Pré-Escolar , Variações do Número de Cópias de DNA/genética , Deficiências do Desenvolvimento/genética , Drosophila melanogaster/genética , Feminino , Fibroblastos , Homozigoto , Humanos , Lactente , Recém-Nascido , Masculino , Hipotonia Muscular/genética , Músculos/patologia , Doenças do Sistema Nervoso/metabolismo , Doenças do Sistema Nervoso/patologia , Neurônios/patologia , Atrofia Óptica/genética , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Síndrome , Adulto Jovem
7.
Hum Genet ; 135(12): 1399-1409, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27681385

RESUMO

Intellectual disabilities are genetically heterogeneous and can be associated with congenital anomalies. Using whole-exome sequencing (WES), we identified five different de novo missense variants in the protein phosphatase-1 catalytic subunit beta (PPP1CB) gene in eight unrelated individuals who share an overlapping phenotype of dysmorphic features, macrocephaly, developmental delay or intellectual disability (ID), congenital heart disease, short stature, and skeletal and connective tissue abnormalities. Protein phosphatase-1 (PP1) is a serine/threonine-specific protein phosphatase involved in the dephosphorylation of a variety of proteins. The PPP1CB gene encodes a PP1 subunit that regulates the level of protein phosphorylation. All five altered amino acids we observed are highly conserved among the PP1 subunit family, and all are predicted to disrupt PP1 subunit binding and impair dephosphorylation. Our data suggest that our heterozygous de novo PPP1CB pathogenic variants are associated with syndromic intellectual disability.


Assuntos
Estudos de Associação Genética , Cardiopatias Congênitas/genética , Deficiência Intelectual/genética , Proteína Fosfatase 1/genética , Adolescente , Adulto , Criança , Pré-Escolar , Exoma/genética , Feminino , Predisposição Genética para Doença , Cardiopatias Congênitas/fisiopatologia , Humanos , Deficiência Intelectual/fisiopatologia , Masculino , Mutação de Sentido Incorreto , Fosforilação/genética
8.
J Mol Diagn ; 18(5): 697-706, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27471182

RESUMO

Next-generation sequencing has evolved technically and economically into the method of choice for interrogating the genome in cancer and inherited disorders. The introduction of procedural code sets for whole-exome and genome sequencing is a milestone toward financially sustainable clinical implementation; however, achieving reimbursement is currently a major challenge. As part of a prospective quality-improvement initiative to implement the new code sets, we adopted Agile, a development methodology originally devised in software development. We implemented eight functionally distinct modules (request review, cost estimation, preauthorization, accessioning, prebilling, testing, reporting, and reimbursement consultation) and obtained feedback via an anonymous survey. We managed 50 clinical requests (January to June 2015). The fraction of pursued-to-requested cases (n = 15/50; utilization management fraction, 0.3) aimed for a high rate of preauthorizations. In 13 of 15 patients the insurance plan required preauthorization, which we obtained in 70% and ultimately achieved reimbursement in 50%. Interoperability enabled assessment of 12 different combinations of modules that underline the importance of an adaptive workflow and policy tailoring to achieve higher yields of reimbursement. The survey confirmed a positive attitude toward self-organizing teams. We acknowledge the individuals and their interactions and termed the infrastructure: human pipeline. Nontechnical barriers currently are limiting the scope and availability of clinical genomic sequencing. The presented human pipeline is one approach toward long-term financial sustainability of clinical genomics.


Assuntos
Assistência à Saúde , Genômica , Informática Médica/métodos , Software , Assistência à Saúde/economia , Assistência à Saúde/métodos , Assistência à Saúde/organização & administração , Exoma , Genômica/economia , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Informática Médica/economia , Encaminhamento e Consulta , Mecanismo de Reembolso , Pesquisa , Inquéritos e Questionários , Fluxo de Trabalho , Recursos Humanos
10.
Am J Hum Genet ; 98(6): 1067-1076, 2016 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-27181684

RESUMO

Evaluating the pathogenicity of a variant is challenging given the plethora of types of genetic evidence that laboratories consider. Deciding how to weigh each type of evidence is difficult, and standards have been needed. In 2015, the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) published guidelines for the assessment of variants in genes associated with Mendelian diseases. Nine molecular diagnostic laboratories involved in the Clinical Sequencing Exploratory Research (CSER) consortium piloted these guidelines on 99 variants spanning all categories (pathogenic, likely pathogenic, uncertain significance, likely benign, and benign). Nine variants were distributed to all laboratories, and the remaining 90 were evaluated by three laboratories. The laboratories classified each variant by using both the laboratory's own method and the ACMG-AMP criteria. The agreement between the two methods used within laboratories was high (K-alpha = 0.91) with 79% concordance. However, there was only 34% concordance for either classification system across laboratories. After consensus discussions and detailed review of the ACMG-AMP criteria, concordance increased to 71%. Causes of initial discordance in ACMG-AMP classifications were identified, and recommendations on clarification and increased specification of the ACMG-AMP criteria were made. In summary, although an initial pilot of the ACMG-AMP guidelines did not lead to increased concordance in variant interpretation, comparing variant interpretations to identify differences and having a common framework to facilitate resolution of those differences were beneficial for improving agreement, allowing iterative movement toward increased reporting consistency for variants in genes associated with monogenic disease.


Assuntos
Pesquisa Biomédica , Testes Genéticos/normas , Variação Genética/genética , Genômica/métodos , Laboratórios/normas , Mutação/genética , Análise de Sequência de DNA/normas , Interpretação Estatística de Dados , Prática Clínica Baseada em Evidências , Exoma/genética , Genoma Humano , Guias como Assunto , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Achados Incidentais , Software , Estados Unidos
11.
Genet Med ; 17(4): 319, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25835197

RESUMO

Genet Med advance online publication, January 22, 2015; doi:10.1038/gim.2014.205. In the Advance Online Publication version, of this article, there is a mistake on page 2 in the first paragraph of the Materials and Methods section. The sentence beginning "Among 3,459 probands initially referred for HCM genetic testing …" the correct number of probands is 3,473 not 3,459. The authors regret the error.

12.
Public Health Genomics ; 18(2): 123-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25612602

RESUMO

As genome sequencing technologies increasingly enter medical practice, genetics laboratories must communicate sequencing results effectively to nongeneticist physicians. We describe the design and delivery of a clinical genome sequencing report, including a one-page summary suitable for interpretation by primary care physicians. To illustrate our preliminary experience with this report, we summarize the genomic findings from 10 healthy participants in a study of genome sequencing in primary care.


Assuntos
Genômica/métodos , Atenção Primária à Saúde , Relatório de Pesquisa , Análise de Sequência , Adulto , Humanos , Comunicação Interdisciplinar , Médicos de Atenção Primária , Atenção Primária à Saúde/normas , Atenção Primária à Saúde/tendências , Relatório de Pesquisa/normas , Relatório de Pesquisa/tendências
13.
Genet Med ; 17(11): 880-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25611685

RESUMO

PURPOSE: Hypertrophic cardiomyopathy (HCM) is caused primarily by pathogenic variants in genes encoding sarcomere proteins. We report genetic testing results for HCM in 2,912 unrelated individuals with nonsyndromic presentations from a broad referral population over 10 years. METHODS: Genetic testing was performed by Sanger sequencing for 10 genes from 2004 to 2007, by HCM CardioChip for 11 genes from 2007 to 2011 and by next-generation sequencing for 18, 46, or 51 genes from 2011 onward. RESULTS: The detection rate is ~32% among unselected probands, with inconclusive results in an additional 15%. Detection rates were not significantly different between adult and pediatric probands but were higher in females compared with males. An expanded gene panel encompassing more than 50 genes identified only a very small number of additional pathogenic variants beyond those identifiable in our original panels, which examined 11 genes. Familial genetic testing in at-risk family members eliminated the need for longitudinal cardiac evaluations in 691 individuals. Based on the projected costs derived from Medicare fee schedules for the recommended clinical evaluations of HCM family members by the American College of Cardiology Foundation/American Heart Association, our data indicate that genetic testing resulted in a minimum cost savings of about $0.7 million. CONCLUSION: Clinical HCM genetic testing provides a definitive molecular diagnosis for many patients and provides cost savings to families. Expanded gene panels have not substantively increased the clinical sensitivity of HCM testing, suggesting major additional causes of HCM still remain to be identified.


Assuntos
Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/genética , Testes Genéticos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Cardiomiopatia Hipertrófica/epidemiologia , Criança , Pré-Escolar , Custos e Análise de Custo , Feminino , Predisposição Genética para Doença , Testes Genéticos/economia , Testes Genéticos/métodos , Testes Genéticos/normas , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos/economia , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Análise de Sequência com Séries de Oligonucleotídeos/normas , Sensibilidade e Especificidade , Adulto Jovem
14.
Genome Biol ; 15(3): R53, 2014 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-24667040

RESUMO

BACKGROUND: There is tremendous potential for genome sequencing to improve clinical diagnosis and care once it becomes routinely accessible, but this will require formalizing research methods into clinical best practices in the areas of sequence data generation, analysis, interpretation and reporting. The CLARITY Challenge was designed to spur convergence in methods for diagnosing genetic disease starting from clinical case history and genome sequencing data. DNA samples were obtained from three families with heritable genetic disorders and genomic sequence data were donated by sequencing platform vendors. The challenge was to analyze and interpret these data with the goals of identifying disease-causing variants and reporting the findings in a clinically useful format. Participating contestant groups were solicited broadly, and an independent panel of judges evaluated their performance. RESULTS: A total of 30 international groups were engaged. The entries reveal a general convergence of practices on most elements of the analysis and interpretation process. However, even given this commonality of approach, only two groups identified the consensus candidate variants in all disease cases, demonstrating a need for consistent fine-tuning of the generally accepted methods. There was greater diversity of the final clinical report content and in the patient consenting process, demonstrating that these areas require additional exploration and standardization. CONCLUSIONS: The CLARITY Challenge provides a comprehensive assessment of current practices for using genome sequencing to diagnose and report genetic diseases. There is remarkable convergence in bioinformatic techniques, but medical interpretation and reporting are areas that require further development by many groups.


Assuntos
Bases de Dados Genéticas/normas , Testes Genéticos/métodos , Genômica/métodos , Revisão da Pesquisa por Pares , Análise de Sequência de DNA/métodos , Criança , Feminino , Organização do Financiamento , Testes Genéticos/economia , Testes Genéticos/normas , Genômica/economia , Genômica/normas , Cardiopatias Congênitas/diagnóstico , Cardiopatias Congênitas/genética , Humanos , Masculino , Miopatias Congênitas Estruturais/diagnóstico , Miopatias Congênitas Estruturais/genética , Análise de Sequência de DNA/economia , Análise de Sequência de DNA/normas
15.
Trials ; 15: 85, 2014 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-24645908

RESUMO

BACKGROUND: Whole genome sequencing (WGS) is already being used in certain clinical and research settings, but its impact on patient well-being, health-care utilization, and clinical decision-making remains largely unstudied. It is also unknown how best to communicate sequencing results to physicians and patients to improve health. We describe the design of the MedSeq Project: the first randomized trials of WGS in clinical care. METHODS/DESIGN: This pair of randomized controlled trials compares WGS to standard of care in two clinical contexts: (a) disease-specific genomic medicine in a cardiomyopathy clinic and (b) general genomic medicine in primary care. We are recruiting 8 to 12 cardiologists, 8 to 12 primary care physicians, and approximately 200 of their patients. Patient participants in both the cardiology and primary care trials are randomly assigned to receive a family history assessment with or without WGS. Our laboratory delivers a genome report to physician participants that balances the needs to enhance understandability of genomic information and to convey its complexity. We provide an educational curriculum for physician participants and offer them a hotline to genetics professionals for guidance in interpreting and managing their patients' genome reports. Using varied data sources, including surveys, semi-structured interviews, and review of clinical data, we measure the attitudes, behaviors and outcomes of physician and patient participants at multiple time points before and after the disclosure of these results. DISCUSSION: The impact of emerging sequencing technologies on patient care is unclear. We have designed a process of interpreting WGS results and delivering them to physicians in a way that anticipates how we envision genomic medicine will evolve in the near future. That is, our WGS report provides clinically relevant information while communicating the complexity and uncertainty of WGS results to physicians and, through physicians, to their patients. This project will not only illuminate the impact of integrating genomic medicine into the clinical care of patients but also inform the design of future studies. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01736566.


Assuntos
Cardiomiopatias/genética , Aconselhamento Genético , Testes Genéticos/métodos , Genoma Humano , Atenção Primária à Saúde/métodos , Projetos de Pesquisa , Análise de Sequência de DNA , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Atitude do Pessoal de Saúde , Cardiomiopatias/diagnóstico , Cardiomiopatias/terapia , Competência Clínica , Currículo , Educação Médica Continuada/métodos , Feminino , Predisposição Genética para Doença , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Capacitação em Serviço , Masculino , Pessoa de Meia-Idade , Fenótipo , Valor Preditivo dos Testes , Prognóstico , Adulto Jovem
16.
BMC Med Genet ; 15: 134, 2014 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-25714468

RESUMO

BACKGROUND: The MedSeq Project is a randomized clinical trial developing approaches to assess the impact of integrating genome sequencing into clinical medicine. To facilitate the return of results of potential medical relevance to physicians and patients participating in the MedSeq Project, we sought to develop a reporting approach for the effective communication of such findings. METHODS: Genome sequencing was performed on the Illumina HiSeq platform. Variants were filtered, interpreted, and validated according to methods developed by the Laboratory for Molecular Medicine and consistent with current professional guidelines. The GeneInsight software suite, which is integrated with the Partners HealthCare electronic health record, was used for variant curation, report drafting, and delivery. RESULTS: We developed a concise 5-6 page Genome Report (GR) featuring a single-page summary of results of potential medical relevance with additional pages containing structured variant, gene, and disease information along with supporting evidence for reported variants and brief descriptions of associated diseases and clinical implications. The GR is formatted to provide a succinct summary of genomic findings, enabling physicians to take appropriate steps for disease diagnosis, prevention, and management in their patients. CONCLUSIONS: Our experience highlights important considerations for the reporting of results of potential medical relevance and provides a framework for interpretation and reporting practices in clinical genome sequencing.


Assuntos
Genoma Humano , Disseminação de Informação/métodos , Projetos de Pesquisa , Análise de Sequência de DNA/métodos , Biologia Computacional , Variação Genética , Genômica , Humanos , Farmacogenética , Ensaios Clínicos Controlados Aleatórios como Assunto , Software
17.
BMC Med Genet ; 14: 68, 2013 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-23815709

RESUMO

BACKGROUND: Variants in the desmin gene (DES) are associated with desminopathy; a myofibrillar myopathy mainly characterized by muscle weakness, conduction block, and dilated cardiomyopathy. To date, only ~50 disease-associated variants have been described, and the majority of these lead to dominant-negative effects. However, the complete genotypic spectrum of desminopathy is not well established. CASE PRESENTATION: Next-generation sequencing was performed on 51 cardiac disease genes in a proband with profound skeletal myopathy, dilated cardiomyopathy, and respiratory dysfunction. Our analyses revealed compound heterozygous DES variants, both of which are predicted to lead to a loss-of-function. Consistent with recessive inheritance, each variant was identified in an unaffected parent. CONCLUSIONS: This case report serves to broaden the variant spectrum of desminopathies and provides insight into the molecular mechanisms of desminopathy, supporting distinct dominant-negative and loss-of-function etiologies.


Assuntos
Cardiomiopatias/genética , Desmina/genética , Predisposição Genética para Doença , Distrofias Musculares/genética , Adulto , Sequência de Bases , Cardiomiopatia Dilatada/genética , Família , Feminino , Testes Genéticos , Variação Genética , Genótipo , Heterozigoto , Humanos , Masculino , Mutação , Linhagem , Alinhamento de Sequência , Análise de Sequência de DNA
18.
Hum Mutat ; 34(1): 191-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22930593

RESUMO

Aminoacyl-tRNA synthetases (ARSs) are ubiquitously expressed enzymes responsible for ligating amino acids to cognate tRNA molecules. Mutations in four genes encoding an ARS have been implicated in inherited peripheral neuropathy with an axonal pathology, suggesting that all ARS genes are relevant candidates for disease in patients with related phenotypes. Here, we present results from a mutation screen of the histidyl-tRNA synthetase (HARS) gene in a large cohort of patients with peripheral neuropathy. These efforts revealed a rare missense variant (c.410G>A/p.Arg137Gln) that resides at a highly conserved amino acid, represents a loss-of-function allele when evaluated in yeast complementation assays, and is toxic to neurons when expressed in a worm model. In addition to the patient with peripheral neuropathy, p.Arg137Gln HARS was detected in three individuals by genome-wide exome sequencing. These findings suggest that HARS is the fifth ARS locus associated with axonal peripheral neuropathy. Implications for identifying ARS alleles in human populations and assessing them for a role in neurodegenerative phenotypes are discussed.


Assuntos
Predisposição Genética para Doença/genética , Histidina-tRNA Ligase/genética , Mutação , Doenças do Sistema Nervoso Periférico/genética , Substituição de Aminoácidos , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Estudos de Coortes , Exoma/genética , Frequência do Gene , Teste de Complementação Genética , Genótipo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Microscopia Confocal , Neurônios Motores/metabolismo , Saccharomyces cerevisiae/genética , Análise de Sequência de DNA/métodos
19.
Hum Mutat ; 33(1): 244-53, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22009580

RESUMO

Charcot-Marie-Tooth (CMT) disease comprises a heterogeneous group of peripheral neuropathies characterized by muscle weakness and wasting, and impaired sensation in the extremities. Four genes encoding an aminoacyl-tRNA synthetase (ARS) have been implicated in CMT disease. ARSs are ubiquitously expressed, essential enzymes that ligate amino acids to cognate tRNA molecules. Recently, a p.Arg329His variant in the alanyl-tRNA synthetase (AARS) gene was found to segregate with dominant axonal CMT type 2N (CMT2N) in two French families; however, the functional consequence of this mutation has not been determined. To investigate the role of AARS in CMT, we performed a mutation screen of the AARS gene in patients with peripheral neuropathy. Our results showed that p.Arg329His AARS also segregated with CMT disease in a large Australian family. Aminoacylation and yeast viability assays showed that p.Arg329His AARS severely reduces enzyme activity. Genotyping analysis indicated that this mutation arose on three distinct haplotypes, and the results of bisulfite sequencing suggested that methylation-mediated deamination of a CpG dinucleotide gives rise to the recurrent p.Arg329His AARS mutation. Together, our data suggest that impaired tRNA charging plays a role in the molecular pathology of CMT2N, and that patients with CMT should be directly tested for the p.Arg329His AARS mutation.


Assuntos
Alanina-tRNA Ligase/genética , Doença de Charcot-Marie-Tooth/genética , Mutação , Aminoacilação de RNA de Transferência/genética , Alanina-tRNA Ligase/metabolismo , Aminoacilação , Arginina/genética , Arginina/metabolismo , Austrália , Axônios , Estudos de Casos e Controles , Doença de Charcot-Marie-Tooth/metabolismo , Doença de Charcot-Marie-Tooth/patologia , Ilhas de CpG , Feminino , França , Genes Dominantes , Ligação Genética , Haplótipos , Histidina/genética , Histidina/metabolismo , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Leveduras
20.
J Clin Invest ; 121(5): 2013-24, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21540551

RESUMO

Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of end-stage renal failure. Identification of single-gene causes of SRNS has generated some insights into its pathogenesis; however, additional genes and disease mechanisms remain obscure, and SRNS continues to be treatment refractory. Here we have identified 6 different mutations in coenzyme Q10 biosynthesis monooxygenase 6 (COQ6) in 13 individuals from 7 families by homozygosity mapping. Each mutation was linked to early-onset SRNS with sensorineural deafness. The deleterious effects of these human COQ6 mutations were validated by their lack of complementation in coq6-deficient yeast. Furthermore, knockdown of Coq6 in podocyte cell lines and coq6 in zebrafish embryos caused apoptosis that was partially reversed by coenzyme Q10 treatment. In rats, COQ6 was located within cell processes and the Golgi apparatus of renal glomerular podocytes and in stria vascularis cells of the inner ear, consistent with an oto-renal disease phenotype. These data suggest that coenzyme Q10-related forms of SRNS and hearing loss can be molecularly identified and potentially treated.


Assuntos
Perda Auditiva Neurossensorial/genética , Mutação , Síndrome Nefrótica/genética , Ubiquinona/genética , Animais , Células COS , Cercopithecus aethiops , Criança , Pré-Escolar , Células HeLa , Perda Auditiva Neurossensorial/complicações , Homozigoto , Humanos , Lactente , Recém-Nascido , Peptídeos e Proteínas de Sinalização Intracelular/genética , Glomérulos Renais/metabolismo , Laminina/genética , Proteínas de Membrana/genética , Síndrome Nefrótica/complicações , Fenótipo , Podócitos/metabolismo , Ratos , Proteínas WT1/genética , Peixe-Zebra
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