© 2017, GENASSIST, Inc.     

By Keith S. Wexler, MBA, Maternal Fetal Medicine, Prenatal Diagnosis and Biotech/Life Sciences Consultant, GENASSIST, Inc.

Paul Wexler, M.D., F.A.C.O.G., Medical Director, GENASSIST, Inc.

Clinical Professor, Department of OB/GYN, University of Colorado Health Sciences Center

Clinical Professor, Division of Genetics/Dept. of Pediatrics, Univ. of Colorado/The Children’s Hospital


[*A recent study, that is ongoing, has suggested a possible relationship between maternal age (35 years or older) and/or paternal age (greater than 40 years) and autism and/or autism spectrum disorder(s) in a child. Reference: Israel & Mt. Sinai, NY.   *Some recent studies have suggested risk may be as high as 1:50 to 1:80.]



Smith-Lemli-Opitz Syndrome is a disorder of variable severity inherited in an autosomal recessive manner (25% if both parents are gene carriers).

Smith-Lemli-Opitz Syndrome is caused by a deficiency in the 7 Dehydrocholesterol Reductase (DHCR-7) enzyme that affects cholesterol metabolism.

Smith-Lemli-Opitz Syndrome affects multiple systems resulting in possible:

  • Cleft palate
  • Characteristic facial features
  • Heart defects
  • Extra fingers and/or extra toes
  • Fusion of second and third toes
  • Underdeveloped male genitalia
  • Variable developmental delay
  • Gastrointestinal problems (occasional)

Smith-Lemli-Opitz Syndrome is reported to affect 1 in 20,000 to 1 in 60,000 births.

Smith-Lemli-Opitz Syndrome gene carriers are more frequent than the incidence of live born suggesting that many Smith-Lemli-Opitz Syndrome infants are miscarried or stillborn.

The diagnosis can be made by serum determination of elevated cholesterol and 7 Dehydrocholesterol/cholesterol ratios.

*Prenatal diagnosis is available.

Treatment is directed at specific findings in the affected individual and cholesterol supplementation with bile acid may alleviate some of the symptoms.

Statin drugs may reduce cholesterol levels.

Analysis: As we head forward in the brave new world of Microarray and/or High Resolution Chromosomal Microarray Analysis (CMA) screening, we will be performing more problem focused amniocentesis, rather than amniocentesis traditionally based upon a mother’s maternal age related risk.

As with any screening test, women of all ages who are detected as being carriers for rare diseases will have the weigh the risks, benefits and limitations of invasive testing.