This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Myosin storage myopathy is an inherited condition that affects the muscles. Signs and symptoms generally begin during infancy or early childhood; however, some affected people may not develop symptoms until early adulthood and there are even reports of people who are asymptomatic into their 40s. Myosin storage myopathy is primarily characterized by muscle weakness with minimal or very slow progression. As a result, affected people may experience delayed motor milestones (i.e. walking), trouble climbing stairs, difficulty lifting arms above shoulder level, and less commonly, breathing problems. Myosin storage myopathy is caused by changes (mutations) in the MYH7 gene and is typically inherited in an autosomal dominant manner. Treatment is generally supportive and may include orthopedic treatments, as well as physical, occupational or speech therapy.
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