Smith-Lemi-Opitz syndrome (SLOS) is an autosomal recessive inborn error of cholesterol biosynthesis due to a deficiency of the last enzyme of the cholesterol synthetic pathway, 7-dehydrocholesterol reductase. Affected patients have low concentrations of cholesterol and elevation of the cholesterol precursor, 7-dehydrocholesterol (7-DHC). Multiple congenital anomalies, dysmorphic facies, and growth and developmental retardation are common. Severely affected males have ambiguous genitalia. We believe that the genital anomalies seen in affected males are due to deficiency of androgens, but this has never been proven.

The infant was diagnosed prenatally with SLOS by sterol analysis of amniotic fluid at 30 weeks gestation. Physical examination on Day 1 of life revealed many of the physical features of SLOS. Biochemical studies confirmed the prenatal diagnosis. The penis measured 1 × 0.7 cm, and was hooded and ventrally bound. He had a third-degree hypospadias and a bifid scrotum. There was hyperpigmentation of the nipples and scrotum.

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