Frequency and ethnic distribution of the common DHCR7 mutation in Smith-Lemli-Opitz syndrome

Am J Med Genet. 2001 Sep 1;102(4):383-6. doi: 10.1002/ajmg.1441.


Smith-Lemli-Opitz syndrome (SLOS) is an inherited multiple malformation syndrome caused by enzymatic deficiency of 3beta-hydroxysterol-Delta(7)-reductase (DHCR7). SLOS is thought to be most common among European Caucasians, with an incidence of 1 in 20,000 to 1 in 30,000 births. To define the carrier rate and ethnic distribution of SLOS, we screened DNA samples from 2,978 unrelated individuals for the most common SLOS mutation (IVS8-1G-->C). Twenty-four heterozygotes of the IVS8-1G-->C mutation were detected in 2,978 individuals of European Caucasian and Black backgrounds. For European Caucasians, the carrier rate for SLOS may be as high as 1 in 30, suggesting an incidence of 1 in 1,700 to 1 in 13,400. This high number is supported by the recent observation of newborn and prenatal incidence of 1 in 22,000 in the Caucasian population. Ours is the first report of the IVS8-1G-->C mutation in persons of African ancestry. Published 2001 Wiley-Liss, Inc.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Europe / epidemiology
  • Europe / ethnology
  • Gene Frequency / genetics*
  • Genetic Carrier Screening
  • Genetic Testing
  • Humans
  • Mutation / genetics*
  • Oxidoreductases / genetics*
  • Oxidoreductases Acting on CH-CH Group Donors*
  • Smith-Lemli-Opitz Syndrome / enzymology*
  • Smith-Lemli-Opitz Syndrome / ethnology
  • Smith-Lemli-Opitz Syndrome / genetics*


  • Oxidoreductases
  • Oxidoreductases Acting on CH-CH Group Donors
  • 7-dehydrocholesterol reductase