Familial occurrence of mitral valve prolapse in X-linked muscular dystrophy.

A high incidence of mitral valve prolapse (MVP) has been reported in patients with X-linked Duchenne muscular dystrophy. In our study MVP was present in six of 22 Duchenne dystrophy cases (27%) followed in the Maryland General Hospital Muscular Dystrophy Clinic. In addition, seven carriers of Duchenne and X-linked benign (Becker) dystrophy had evidence of MVP. Autosomal dominant transmission of MVP was present in four families. The unusually high prevalence of MVP in families with X-linked muscular dystrophy may have potential value in the recognition of the carrier trait.