DHCR7 and Smith-Lemli-Opitz syndrome: Pathogenic variants in DHCR7 result in Smith–Lemli–Opitz syndrome [SLOS, MIM *270400], an autosomal recessive disorder caused by impaired cholesterol metabolism and characterized by dysmorphic facial features, multiple congenital anomalies involving skeletal, cardiovascular, respiratory, and genitourinary systems.