GCB Masthead
Smith-Lemli-Opitz Syndrome (SLOS) Smith-Lemli-Opitz syndrome (SLOS, RSH syndrome) is an autosomal recessive, multiple malformation, mental retardation syndrome due to an inborn error of cholesterol biosynthesis. Based on clinical studies, the incidence rate of SLOS is 1:10,000 to 1:60,000. Molecular studies have shown a carrier frequency of about 1% for the most common SLOS mutant allele in North American populations. Specifically, these patients have a deficiency of 3- beta-hydroxysterol delta-7-reductase activity due to mutation of the 3-beta-hydroxysterol 7-reductase gene (DHCR7). This enzymatic deficiency impairs the conversion of 7-dehydrocholesterol (7-DHC) to cholesterol in the last step of cholesterol biosynthesis. This deficiency causes extremely variable clinical, physical, and behavioral manifestations from presenting as a lethal disorder with multiple major congenital anomalies to presenting with minor physical stigmata, as well as behavioral and learning disabilities, autism spectrum disorders, aggression, self injury, sleep problems, irritability, and attention deficit hyperactivity disorder (ADHD). Currently, therapy is based on dietary cholesterol supplementation.

Research Projects

Investigation of Simvastatin Therapy in Smith-Lemli-Opitz Syndrome

SLOS Behavioral Phenotype Study