Cholesterol drug appears beneficial for Smith-Lemli-Opitz syndrome

NIH study repurposes simvastatin as potential rare disease treatment


Simvastatin, commonly prescribed for reducing cholesterol, may be effective for treating Smith-Lemli-Opitz syndrome (SLOS), according to a new study from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), part of the National Institutes of Health. The study is the first randomized, double-blinded, placebo-controlled trial of a statin drug for SLOS, a rare genetic disease that currently has no cure or approved treatment.

SLOS affects the nervous system and results in behavioral symptoms similar to those seen in autism. The disease stems from mutations in a gene called DHCR7, which helps carry out the last step of the body’s cholesterol production. The mutations lead to cholesterol deficiency and a buildup of cholesterol precursors called dehydrocholesterol (DHC), which can impair fetal development and nervous system function.

Previous studies suggest that simvastatin may help in treating in SLOS, likely by boosting the activity of a poorly functioning DHCR7 gene. In the current study, 18 SLOS patients between the ages of 4 and 18 received treatment with either simvastatin or placebo for the first half of the study, then switched treatments for the second half.

The researchers found that simvastatin significantly lowered levels of DHC in 12 out of 18 participants. The participants also had improved scores on a test measuring irritability. The drug appeared safe for SLOS patients, with no evidence of liver or muscle toxicity. However, one participant developed cataracts, which cloud the eye lens and impair vision, after the study was completed. The authors cautioned that more research is needed to determine if simvastatin is appropriate for long-term treatment of SLOS. Overall, the results suggest that simvastatin or other drugs that enhance the activity of the DHCR7 gene may show promise in treating SLOS.

The study received additional funding from NIH’s National Center for Advancing Translational Sciences and Autism Speaks.


Wassif CA, Kratz L, Sparks SE, Wheeler C, Bianconi S, Gropman A, Calis KA, Kelley RI, Tierney E, and Porter FD. A placebo-controlled trial of simvastatin therapy in Smith-Lemli-Opitz syndrome. Genetics in Medicine DOI: 10.1038/GIM.2016.102 (2016).


About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): NICHD conducts and supports research in the United States and throughout the world on fetal, infant and child development; maternal, child and family health; reproductive biology and population issues; and medical rehabilitation. For more information, visit NICHD’s website.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

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