Smith-Lemli-Opitz Syndrome

Background and History: 

This is a malformation disorder named after the three authors who first described it in 1964.  It is a disorder of cholesterol synthesis and the clinical features are many with considerable variation among individuals.

Clinical Correlations: 

Most individuals have some growth and mental delay.  They often exhibit irritable and hyperactive behavior and some have autistic features.  They are sometimes described as ‘floppy’ babies and are often short in length.  The brain may be small and underdeveloped.  The jaw is small, and cleft palate, extra digits, a short nose, and ambiguous genitalia may be present.  Many organ systems, including the heart, lungs, kidneys, gastrointestinal tract have one or more malformations.  The eyes are prominent and the upper lids appear to droop.  Cataracts and underdevelopment of the optic nerves have been noted in some cases.


This is an autosomal recessive disorder with a horizontal pattern of inheritance.  It is caused by a gene mutation that results in impaired cholesterol synthesis.

Diagnosis and Prognosis: 

Those most severely affected may be miscarried or stillborn.  Newborns with this disorder often appear ill at birth and infant mortality is high as a result of multiple organ malformations.  There is considerable variation in severity of symptoms, however, and many children live longer.  The diagnosis may be made by a pediatrician but often other specialists contribute as well.  Dietary supplementation of cholesterol has been found beneficial in some patients.

Additional Information
Autosomal recessive