Systolic prolapse of the mitral valve in Noonan's syndrome.

A thirty-five-year-old woman with Noonan's syndrome (Turner phenotype with normal chromosome pattern) had mitral valve prolapse and mitral insufficiency associated with the auscultatory findings of a midsystolic click and late systolic murmur. Selective left-ventricular angiocardiography also showed eccentric hypertrophy of the left ventricle. To our knowledge, this is the first reported instance of mitral valve prolapse occurring in association with Noonan's syndrome.