RSH/Smith-Lemli-Opitz syndrome (SLOS) is one that causes mental retardation. It is common in the Caucasian population but rare in African American and African black populations. It has been shown that SLOS is caused by a specific defect in DHCR7, an enzyme used in cholesterol metabolism. Studies have already been done to determine the frequency of the SLOS-causing mutations in various geographic Caucasian populations. This study will investigate the frequency of the DHCR7 mutations in the African American population. If the frequency observed suggests that SLOS cases are not being identified in this ethnic group, the study will provide the rationale for future studies to identify these patients. The sample size will be 1,600. The study population will consist of archived biological specimens in the form of newborn screening blood spots from two newborn screening centers, one in Maryland and one in Pennsylvania. Subjects will be of African American ethnicity, including blacks of African, Caribbean, and Central American descent. Genomic DNA will be extracted from blood spots and screened for the six common SLOS mutations. If SLOS syndrome is found, followup will be attempted for the Maryland samples (the Pennsylvania samples will be totally anonymous).

NCT00017732

Conditions

1. Smith-Lemli-Opitz Syndrome

MeSH:Cleft Palate Hypertelorism Hypospadias Genetic Diseases, X-Linked Smith-Lemli-Opitz Syndrome Syndrome

HPO:Cleft palate Hypertelorism

In these Caucasian populations, the most common mutations (IVS8-1G>C, W151X, V326L, R352W, R404C and T93M) account for 60% of SLOS mutant alleles. --- V326L --- --- R352W ---