Autosomal dominant centronuclear myopathy

Autosomal dominant centronuclear myopathy (AD-CNM), also known as dynamin 2-related centronuclear myopathy, is a rare inherited muscle disorder characterized by the abnormal central positioning of nuclei within muscle fibers, which are normally located at the periphery. This condition is most commonly caused by mutations in the DNM2 gene (dynamin 2), and less frequently in the BIN1 gene. It primarily affects skeletal muscles throughout the body, leading to progressive muscle weakness and wasting. The clinical presentation of AD-CNM is variable but typically includes slowly progressive limb weakness (often more prominent in distal muscles initially, later involving proximal muscles), facial weakness, ptosis (drooping eyelids), and ophthalmoplegia (limited eye movements). Many patients experience mild to moderate symptoms, and the condition tends to be less severe than the X-linked form of centronuclear myopathy. Onset is variable, ranging from childhood to adulthood, though many patients present in adolescence or early adulthood. Additional features may include foot drop, difficulty with fine motor tasks, and respiratory involvement in more advanced cases. There is currently no cure or disease-specific treatment for autosomal dominant centronuclear myopathy. Management is supportive and multidisciplinary, focusing on physical therapy to maintain mobility and muscle function, orthopedic interventions for skeletal complications, respiratory monitoring and support when needed, and occupational therapy. Genetic counseling is recommended for affected families. Diagnosis is confirmed through muscle biopsy showing characteristic centrally placed nuclei and genetic testing identifying pathogenic variants in DNM2 or BIN1.

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