Autosomal dominant distal myopathy

Autosomal dominant distal myopathy (Orphanet code 206650) is a group of inherited muscle disorders characterized by progressive weakness and wasting that predominantly affects the distal muscles — those located in the hands, forearms, lower legs, and feet. Unlike many other myopathies that primarily involve proximal (shoulder and hip girdle) muscles, distal myopathies begin in the extremities and may gradually progress to involve more proximal muscle groups over time. Several distinct subtypes fall under this classification, including Welander distal myopathy, Laing distal myopathy (MPD1), and others, each caused by mutations in different genes but sharing the autosomal dominant inheritance pattern. Clinical features typically include difficulty with fine motor tasks such as buttoning clothes or gripping objects, foot drop, tripping, and progressive gait abnormalities. Onset is generally in adulthood, though some subtypes may present earlier. Serum creatine kinase levels may be normal or mildly elevated. Muscle biopsy findings can vary by subtype but often show myopathic changes, and in some forms, rimmed vacuoles may be observed. Electromyography typically reveals a myopathic pattern. There is currently no cure or disease-modifying treatment for autosomal dominant distal myopathies. Management is supportive and symptomatic, including physical therapy to maintain mobility and strength, occupational therapy for hand function, orthotic devices such as ankle-foot orthoses for foot drop, and regular monitoring by a neuromuscular specialist. Genetic counseling is recommended for affected individuals and their families, as each child of an affected person has a 50% chance of inheriting the causative mutation.

Common questions about Autosomal dominant distal myopathy