Fetal Smith-Lemli-Opitz syndrome can be detected accurately and reliably by measuring amniotic fluid dehydrocholesterols

Prenat Diagn. 1998 Jul;18(7):651-8.

Abstract

The Smith-Lemli-Opitz syndrome, characterized by limb, face and organ abnormalities, and mental retardation, is caused by an inherited block in the step of cholesterol biosynthesis in which the delta 7 double bond of 7-dehydrocholesterol is reduced. It is diagnosed by the presence of markedly elevated levels of 7-dehydrocholesterol and 8-dehydrocholesterol in plasma and tissue. We measured amniotic fluid sterols in 15 pregnancies in 13 women who had previously carried an affected fetus. Cholesterol, 7-dehydrocholesterol and 8-dehydrocholesterol concentrations averaged 18 +/- 3, 9.8 +/- 2.9 and 5.0 +/- 1.7 micrograms/ml, respectively, in seven pregnancies with an affected fetus or child. In contrast, these levels were 19 +/- 3, 0.05 +/- 0.01 and < 0.005 micrograms/ml, respectively, in eight increased-risk pregnancies with normal outcomes and 16 +/- 2, 0.07 +/- 0.01 and < 0.005 micrograms/ml in normal controls. 7-dehydrocholesterol concentrations, 2.2-26 and 0.05-0.10 micrograms/ml in pregnancies with an affected and unaffected fetus, respectively, did not overlap. Thus, abnormally elevated amniotic fluid dehydrocholesterol concentrations are an accurate predictor of fetal Smith-Lemli-Opitz syndrome. A false-positive or a false-negative result is highly unlikely.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Amniocentesis*
  • Amniotic Fluid / chemistry*
  • Cholestadienols / analysis*
  • Cholesterol / analysis
  • Dehydrocholesterols / analysis*
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Gestational Age
  • Humans
  • Pregnancy
  • Pregnancy Outcome
  • Reference Values
  • Smith-Lemli-Opitz Syndrome / diagnosis*

Substances

  • Cholestadienols
  • Dehydrocholesterols
  • cholesta-5,8-dien-3 beta-ol
  • Cholesterol
  • 7-dehydrocholesterol