Rapid Molecular Diagnosis of Genetically Inherited Neuromuscular Disorders Using Next-Generation Sequencing Technologies.

Neuromuscular diseases are genetically highly heterogeneous, and differential diagnosis can be challenging. Over a 3-year period, we prospectively analyzed 268 pediatric and adult patients with a suspected diagnosis of inherited neuromuscular disorder (INMD) using comprehensive gene-panel analysis and next-generation sequencing. The rate of diagnosis increased exponentially with the addition of genes to successive versions of the INMD panel, from 31% for the first iteration (278 genes) to 40% for the last (324 genes). The global mean diagnostic rate was 36% (97/268 patients), with a diagnostic turnaround time of 4-6 weeks. Most diagnoses corresponded to muscular dystrophies/myopathies (68.37%) and peripheral nerve diseases (22.45%). The most common causative genes, TTN, RYR1, and ANO5, accounted for almost 30% of the diagnosed cases. Finally, we evaluated the utility of the differential diagnosis tool Phenomizer, which established a correlation between the phenotype and molecular findings in 21% of the diagnosed patients. In summary, comprehensive gene-panel analysis of all genes implicated in neuromuscular diseases facilitates a rapid diagnosis and provides a high diagnostic yield.

Is the Next Generation Sequencing the Essential Tool for the Early Diagnostic Approach in Congenital Muscular Dystrophy? New Mutation in the Gen LMNA Associated with Serious Phenotype.

BACKGROUND: Laminopathies are a group of diseases caused by mutations in the LMNA gene. Congenital dystrophy of the LMN is a rare disease, with less than 100 cases described in the literature. OBJECTIVES AND MATERIALS AND METHODS: We present the clinical case of a patient with congenital muscular dystrophy associated with an undescribed mutation in the LMNA gene. RESULTS: The patient presented progressive motor delay from 10 months with a physical examination consisting of global hypotonia, bilateral winged scapula, areflexia, hip and knee flexion posture, and positive Gowers. The patient developed progressive weakness with neck tone loss, functional impairment, and loss of gait at 5 years. CONCLUSIONS: To date, more than 20 mutations associated with congenital LMNA muscular dystrophy have been identified, most due to a single amino acid change (aa), few due to the gain or loss of several aa as in our patient.