Chronic pain as a presenting feature of dysferlinopathy.

Dysferlinopathies, caused by mutations in the dysferlin gene (DYSF) encoding the dysferlin protein, are a clinically heterogeneous group of autosomal recessive muscular dystrophies whose phenotypic spectrum is still evolving. Here we described a patient reporting diffuse muscular pain non related to physical exercise, mimicking fibromyalgic syndrome. Electroneuromyography was normal. Magnetic resonance imaging (MRI) of skeletal muscles found fatty replacement on T1-weighted and hyperintensity on T2-weighted and short tau inversion recovery (STIR) sequences in the adductor magnus, the vastus medialis, the gastrocnemius lateralis and medialis. A significant decrease in dysferlin expression was observed by immunohistochemistry in the muscle biopsy from the deltoid, which was confirmed by Western blot (WB) analysis. Genetic testing confirmed the diagnosis of dysferlinopathy with the presence of two heterozygous variants. We report a new clinical presentation with confounding features for dysferlinopathy, posing a diagnostic dilemma and widening the clinical spectrum of dysferlin myopathies.