SMITH-LEMLI-OPITZ-SYNDROME - PHENOTYPIC EXTREME WITH MINIMAL CLINICALFINDINGS

Smith-Lemli-Opitz syndrome (SLO) is caused by inherited enzymatic defi ciency of 7-dehydrocholesterol-Delta(7)-reductase and resultant choles terol deficiency. It comprises a characteristic combination of facial features, malformations, and mental retardation. We report on three re lated patients (two brothers and their first cousin) with mental retar dation and minimal physical signs in whom the diagnosis of SLO was del ayed for a number of years. The presence of a third-degree relative in the absence of consanguinity in this family supports the proposed hig h population carrier frequency, Our report suggests that cases of mild SLO remain undiagnosed and untreated, and that awareness of this comm on cause of mental retardation is low. (C) 1998 Wiley-Liss, Inc.