Nonlethal CHRNA1-Related Congenital Myasthenic Syndrome with a Homozygous Null Mutation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fondation Maladies RaresFrance Genomique National infrastructureUniv Sao Paulo, Dept Neurol, Fac Med, Ave Dr Eneas de Carvalho Aguiar 255, 5 Andar, BR-05403900 Sao Paulo, Brazil|Inst Genom, Ctr Natl Genotypage, Evry, FranceUniv Fed Sao Paulo, Dept Neurol, Setor Doencas Neuromusculares, Sao Paulo, BrazilNouvel Hop Civil, Fac Med, Lab Diagnost Genet, Strasbourg, FranceUniv Strasbourg, Coll France, Dept Translat Med & Neurogenet, IGBMC,INSERM U964,CNRS UMR7104, Illkirch Graffenstaden, FranceSetor de Doenças Neuromusculares, Departamento de Neurologia, Universidade Federal de São Paulo São Paulo, BrazilCAPES: 1286/51-2France Genomique National infrastructure: ANR-10-INBS-09Web of Scienc

An Integrated Diagnosis Strategy for Congenital Myopathies

WOS: 000321738400157PubMed ID: 23826317Congenital myopathies are severe muscle disorders affecting adults as well as children in all populations. The diagnosis of congenital myopathies is constrained by strong clinical and genetic heterogeneity. Moreover, the majority of patients present with unspecific histological features, precluding purposive molecular diagnosis and demonstrating the need for an alternative and more efficient diagnostic approach. We used exome sequencing complemented by histological and ultrastructural analysis of muscle biopsies to identify the causative mutations in eight patients with clinically different skeletal muscle pathologies, ranging from a fatal neonatal myopathy to a mild and slowly progressive myopathy with adult onset. We identified RYR1 (ryanodine receptor) mutations in six patients and NEB (nebulin) mutations in two patients. We found novel missense and nonsense mutations, unraveled small insertions/deletions and confirmed their impact on splicing and mRNA/protein stability. Histological and ultrastructural findings of the muscle biopsies of the patients validated the exome sequencing results. We provide the evidence that an integrated strategy combining exome sequencing with clinical and histopathological investigations overcomes the limitations of the individual approaches to allow a fast and efficient diagnosis, accelerating the patient's access to a better healthcare and disease management. This is of particular interest for the diagnosis of congenital myopathies, which involve very large genes like RYR1 and NEB as well as genetic and phenotypic heterogeneity.Institut National de la Sante et de la Recherche Medicale (INSERM)Institut National de la Sante et de la Recherche Medicale (Inserm); Centre national de la recherche scientifique (CNRS)Centre National de la Recherche Scientifique (CNRS); University of Strasbourg; College de France; GIS Institute; Association Francaise contre les myopathiesAssociation Francaise contre les Myopathies; Muscular Dystrophy Association (United States of America)Muscular Dystrophy Association; Myotubular Trust; Agence Nationale de la Recherche (ANR)French National Research Agency (ANR); Muscular Dystrophy Association (MDA)Muscular Dystrophy Association [2010-52655]This work was supported by Institut National de la Sante et de la Recherche Medicale (INSERM), Centre national de la recherche scientifique (CNRS), University of Strasbourg, College de France and grants from ANR, GIS Institute for rare diseases and IBiSA, Association Francaise contre les myopathies, Muscular Dystrophy Association (United States of America) and the Myotubular Trust. This work was supported by the INSERM, the CNRS, University of Strasbourg, College de France and grants from the Agence Nationale de la Recherche (ANR, grant CM-WES), Muscular Dystrophy Association (MDA, grant 2010-52655) and Myotubular Trust. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Different Mutations in the LMNA Gene Cause Autosomal Dominant and Autosomal Recessive Emery-Dreifuss Muscular Dystrophy

Emery-Dreifuss muscular dystrophy (EMD) is a condition characterized by the clinical triad of early-onset contractures, progressive weakness in humeroperoneal muscles, and cardiomyopathy with conduction block. The disease was described for the first time as an X-linked muscular dystrophy, but autosomal dominant and autosomal recessive forms were reported. The genes for X-linked EMD and autosomal dominant EMD (AD-EMD) were identified. We report here that heterozygote mutations in LMNA, the gene for AD-EMD, may cause diverse phenotypes ranging from typical EMD to no phenotypic effect. Our results show that LMNA mutations are also responsible for the recessive form of the disease. Our results give further support to the notion that different genetic forms of EMD have a common pathophysiological background. The distribution of the mutations in AD-EMD patients (in the tail and in the 2A rod domain) suggests that unique interactions between lamin A/C and other nuclear components exist that have an important role in cardiac and skeletal muscle function

Phenotype variability and natural history of X-linked myopathy with excessive autophagy

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A Roma founder BIN1 mutation causes a novel phenotype of centronuclear myopathy with rigid spine

OBJECTIVE: To describe a large series of BIN1 patients, in which a novel founder mutation in the Roma population of southern Spain has been identified. METHODS: Patients diagnosed with centronuclear myopathy (CNM) at 5 major reference centers for neuromuscular disease in Spain (n = 53) were screened for BIN1 mutations. Clinical, histologic, radiologic, and genetic features were analyzed. RESULTS: Eighteen patients from 13 families carried the p.Arg234Cys variant; 16 of them were homozygous for it and 2 had compound heterozygous p.Arg234Cys/p.Arg145Cys mutations. Both BIN1 variants have only been identified in Roma, causing 100% of CNM in this ethnic group in our cohort. The haplotype analysis confirmed all families are related. In addition to clinical features typical of CNM, such as proximal limb weakness and ophthalmoplegia, most patients in our cohort presented with prominent axial weakness, often associated with rigid spine. Severe fat replacement of paravertebral muscles was demonstrated by muscle imaging. This phenotype seems to be specific to the p.Arg234Cys mutation, not reported in other BIN1 mutations. Extreme clinical variability was observed in the 2 compound heterozygous patients for the p.Arg234Cys/p.Arg145Cys mutations, from a congenital onset with catastrophic outcome to a late-onset disease. Screening of European Roma controls (n = 758) for the p.Arg234Cys variant identified a carrier frequency of 3.5% among the Spanish Roma. CONCLUSION: We have identified a BIN1 founder Roma mutation associated with a highly specific phenotype, which is, from the present cohort, the main cause of CNM in Spain

Objective evaluation of clinical actionnability for genes involved in myopathies: 51 promising genes

International audienc

Objective evaluation of clinical actionnability for genes involved in myopathies: 51 promising genes

International audienc