Smith-Lemli-Opitz syndrome: New mutation with a mild phenotype Academic Article uri icon

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  • Smith-Lemli-Opitz syndrome (SLOS) (Online Mendelian Inheritance in Man, OMIM, 2001, for SLOS, MIM 270400) is an autosomal recessive disorder of cholesterol biosynthesis caused by mutations of the 3beta-hydroxysterol Delta(7)-reductase gene, DHCR7. We report on a female infant with an exceptionally mild phenotype of SLOS, in whom molecular studies identified a new mutation in DHCR7. The proposita initially presented with feeding difficulties, failure to thrive, hypotonia, mild developmental delay, and oral tactile aversion. She had minor facial anomalies and 2-3 syndactyly of her toes in both feet. The plasma cholesterol was borderline low at 2.88 mmol/L (normal 2.97-4.40 mmol/L). Elevated plasma 7-dehydrocholesterol level of 200.0 micromol/L confirmed the clinical diagnosis of SLOS. Molecular analysis demonstrated compound heterozygosity for IVS8-1G -->C and Y280C, a new missense mutation in DHCR7. Since the other mutation in this patient is a known null mutation, this newly discovered mutation is presumably associated with significant residual enzyme activity and milder expression of clinical phenotype.


  • Prasad, Chitra
  • Marles, Sandra
  • Prasad, Asuri N
  • Nikkel, Sarah
  • Longstaffe, Sally
  • Peabody, Deborah
  • Eng, Barry
  • Wright, Sarah
  • Waye, John
  • Nowaczyk, Malgorzata

publication date

  • February 15, 2002