Two unrelated patients with novel homozygous missense mutations (L86P and A92T) in caveolin-3 gene (CAV3), presenting with a severe form of rippling muscle disease (RMD), are reported from the University of Bonn, and other centers in Germany. Patient 1 had severe muscle stiffness from early childhood and contractures of the Achilles tendons. Patient 2 had slowly progressive muscle weakness beginning in early adulthood. Symptoms were restricted to skeletal muscles, and heart muscle was not affected. 
COMMENT. Hereditary rippling muscle disease (RMD) is a rare autosomal dominant, nonprogressive myopathy characterized by increased muscle irritability (percussion-induced contractions), electrically silent wave-like contractions (rippling muscle), and muscle mounding with percussion. The above authors have previously reported mutations in CAV-3 in families with RMD and in one sporadic case of RMD. CAV-3 mutations may also occur in limb-girdle muscular dystrophy 1C, distal myopathy, and in children with elevated CK without myopathy.