Smith-Lemli-Opitz Syndrome and Cholic Acid

Inclusion Criteria

• Ages 2-25 years.
• Participants (or their parents/legally-authorized representative) must provide signed informed consent.
• Assent must be obtained from those participants ages 7-17 years who are intellectually capable of understanding this study.
• Diagnosis of SLOS based on clinical features and biochemical + genetic confirmation.
• Participants are capable of traveling to the STAIR study site.
• Fasting plasma cholesterol ≤125 mg/dL during the Qualification Phase must be established before starting cholic acid therapy.
• Clinically stable at the time of enrollment
• Participants must be on a constant dietary cholesterol intake for at least 3-months prior to treatment with cholic acid.
• Participants must agree to make no changes in cholesterol supplementation during the STAIR study.
• SLOS participants who are taking antioxidants will be included. Participants must agree to make no changes in the antioxidant dose during this study.
• For females of childbearing age (who have begun menstruating), a negative pregnancy test must be documented at the start of the study (week 0/ baseline) and at the end of cholic acid administration (week 8).

Exclusion Criteria

• Participants are unable to provide signed informed consent and/or verbal assent.
• Participants have an unstable clinical condition that would prevent completion of the study. Medically unstable participants would include those with severe liver disease, complex birth defects such as severe heart disease or renal dysplasia, those with severe respiratory compromise requiring tracheostomy, or those who are not likely to survive longer than 1 year.
• Participants are taking drugs, nutraceuticals, probiotics or other compounds that are known or suspected to affect sterol metabolism.
• Participants have transaminase elevations (>3-fold above the reference range) at baseline.