Williams syndrome: a guide to diagnosis and treatment.

Williams syndrome is a congenital disorder characterized by mental retardation, vascular abnormalities including supravalvular aortic stenosis, and a loquacious personality. The genetic etiology of this syndrome has recently been isolated to the seventh chromosome, namely the elastin gene. Initial diagnosis of Williams syndrome rests largely with practitioners who see children in the first two years of a child's life, and the health and longevity of individuals with the disorder may depend heavily on accurate and timely diagnosis. Although often diagnosed in childhood, the adolescent and adult with Williams syndrome may also benefit from the diagnostic skills of an alert physician.