Skeletal Muscle Involvement in Wilson Disease: Clinical and Magnetic Resonance Imaging (MRI) Observations in 2 Families.

The calf muscle involvement could be attributed to muscle edema due to copper-induced muscle toxicity mediated by inhibition of Na+/K+-ATPase on cellular membranes of fast-twitch gastrocnemii muscles which contain predominant type II myofiber. In Wilson disease patients with calf pain or cramps, muscle MRI may show nonspecific gastrocnemius hyperintensity. Further evaluation may give insight into its pathophysiology.