Miyoshi Muscular Dystrophy 3

A rare autosomal recessive distal myopathy with characteristics of early adult-onset slowly progressive often asymmetrical lower limb muscle weakness initially affecting the calves (with relative anterior muscle sparing) and later proximal muscle involvement, as well as highly elevated creatine kinase (CK) serum levels. Age at onset ranges from 20 to 50 years. Clinical manifestations can be mild or subjectively nonexistent in spite of presenting clear changes on muscle imaging. Caused by loss of function mutations in the gene ANO5 (11p14.3) which encodes a protein highly expressed in skeletal and cardiac muscle, as well as bone.