Aortic root dilatation and mitral valve prolapse in the fragile X syndrome.

Forty patients with fragile X [fra(X)] or Martin-Bell syndrome, confirmed by chromosome analysis, underwent full cardiac evaluation including physical examination, chest film, electrocardiography (ECG), and M-mode and 2-dimensional echocardiography. Thirty-four males and six females were studied. Although all patients were asymptomatic, seven males were found to have mild aortic root dilatation. All seven also had evidence of mitral valve prolapse. Twenty-two (55%) of the study patients had mitral valve prolapse with either a click or murmur heard on physical examination and confirmation by M-mode echocardiography. The frequency of mitral valve prolapse was the same in males and females, but 80% of males older than 18 years had mitral valve prolapse. These findings support the hypothesis of a connective tissue dysplasia in the fra(X) syndrome.