Increased first trimester nuchal translucency as a prenatal manifestation of Smith-Lemli-Opitz syndrome

Am J Med Genet. 1995 Sep 25;58(4):374-6. doi: 10.1002/ajmg.1320580415.


Routine ultrasound examination at 11 weeks of gestation in a woman with no family history of genetic disease demonstrated increased accumulation of fluid in the fetal nuchal region. In view of the association of this defect with chromosomal abnormalities, fetal karyotyping was performed by chorion villus sampling and this demonstrated a normal 46,XY karyotype. Subsequent scans showed resolution of the nuchal fluid, and at the 20-week scan the fetal genitalia appeared to be female. Fetal blood sampling confirmed a normal male karyotype and fetoscopy confirmed the presence of female external genitalia. The parents elected to terminate the pregnancy, and postmortem findings were indicative of Smith-Lemli-Opitz syndrome. This was confirmed by the finding of increased levels of 7-dehydrocholesterol in cultured skin fibroblasts.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Cells, Cultured
  • Chorionic Villi Sampling
  • Dehydrocholesterols / analysis
  • Female
  • Fetal Diseases / diagnostic imaging*
  • Fetal Diseases / embryology
  • Fetoscopy
  • Fibroblasts / chemistry
  • Humans
  • Karyotyping
  • Male
  • Neck / diagnostic imaging*
  • Oxidoreductases / deficiency
  • Oxidoreductases Acting on CH-CH Group Donors*
  • Pregnancy
  • Smith-Lemli-Opitz Syndrome / diagnostic imaging*
  • Smith-Lemli-Opitz Syndrome / embryology
  • Ultrasonography


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