What is Miyoshi myopathy?
Myopathy simply means “muscle disease.” Miyoshi myopathy (MM) is a form of muscular dystrophy which was first described in the medical literature by Miyoshi in 1967. Although first identified in Japan, it occurs worldwide. Miyoshi is caused by defects in the gene for the protein dysferlin. Miyoshi myopathy is in the category of distal muscular dystrophies, which means that the muscles most strongly affected are in the calves, forearms, hands, or feet. Most forms of muscular dystrophy preferentially affect proximal muscles (those in the hips, thighs, or shoulders), so those that don’t follow that pattern were grouped together for classification purposes. There are many forms of distal myopathy, which don’t have anything in common on a genetic or biochemical level. Miyoshi myopathy is distinctive among the distal myopathies in several respects: • It has a recessive inheritance pattern. This means that in most cases there is no family history. • The first muscles to be affected are typica
