 This 10-week study will evaluate and compare behavior changes in children with Smith-Lemli-Opitz syndrome SLOS who are taking cholesterol supplementation versus those who are not on cholesterol supplementation. SLOS is a genetic disorder that affects the development of children both before and after birth. An enzyme deficiency in these children results in low levels of cholesterol, which can cause a variety of birth defects and behavioral problems. Typical abnormal physical features of patients include a small head, drooping eyelids, small upturned nose, small chin, cleft palate, heart defects, and extra fingers or toes. 