Smith-Lemli-Opitz syndrome: biochemical before clinical diagnosis; early dietary management.

Pursuit of a possible metabolic basis for an unrecognized pattern of multiple congenital anomalies in a newborn girl led to the detection of a huge elevation of plasma 7-dehydrocholesterol at age 8 months. The biochemical findings and the evolving clinical picture led to the diagnosis of Smith-Lemli-Opitz syndrome at age 11 months. High cholesterol diet may have improved the rate of developmental progress.