Genetic analysis of muscular dystrophies: our experience in Mexico.

Muscular dystrophies are a group of well-defined genetic disorders characterized by the variable distribution of muscle wasting and progressive weakness. The diagnosis and treatment of these diseases remain challenging due to genetic heterogeneity and clinical overlapping. Herein, we describe our 10 years' experience with the diagnosis and management of muscular dystrophy patients. In total, 169 patients were screened for pathogenic variants in eleven genes linked to frequent muscular dystrophies using MLPA and NGS sequencing panels. Most frequent muscular dystrophies found in the Mexican population were dystrophinopathies, dysferlinopathies and calpainopathies. Novel variants were found in genes: DMD, CAPN3, DYSF, and FKRP. For Duchenne muscular dystrophy, improvements in early diagnosis and prolonged ambulation were achieved, on the contrary, for limb-girdle muscular dystrophies and congenital muscular dystrophies, uncomplimentary follow-up and lack of detection strategies were observed. For most common muscular dystrophies, improvements in diagnosis and management have been achieved in the last 10 years, due to a collaborative effort done nationwide.

Comparison of mutation profiles in the Duchenne muscular dystrophy gene among populations: implications for potential molecular therapies.

Novel therapeutic approaches are emerging to restore dystrophin function in Duchenne Muscular Dystrophy (DMD), a severe neuromuscular disease characterized by progressive muscle wasting and weakness. Some of the molecular therapies, such as exon skipping, stop codon read-through and internal ribosome entry site-mediated translation rely on the type and location of mutations. Hence, their potential applicability worldwide depends on mutation frequencies within populations. In view of this, we compared the mutation profiles of the populations represented in the DMD Leiden Open-source Variation Database with original data from Mexican patients (n = 162) with clinical diagnosis of the disease. Our data confirm that applicability of exon 51 is high in most populations, but also show that differences in theoretical applicability of exon skipping may exist among populations; Mexico has the highest frequency of potential candidates for the skipping of exons 44 and 46, which is different from other populations (p < 0.001). To our knowledge, this is the first comprehensive comparison of theoretical applicability of exon skipping targets among specific populations.