A Study of Chenodeoxycholic Acid (CDCA) in Newly Diagnosed Participants With Cerebrotendinous Xanthomatosis (CTX)

Inclusion Criteria: * Signed informed consent form (or assent form as appliable) * Aged from 2 to 75 years old * Has a new or suspected diagnosis of CTX as defined by an elevated plasma cholestanol concentration (\>10 mg/L/\>25.7 μmol/L) in conjunction with a clinical presentation consistent with the diseased as assessed by the investigator * Has never received treatment with CDCA * Has never received treatment with other bile acid products Exclusion Criteria: * Any medical condition that, in the opinion of the investigator, precludes the participant's participation in the study * Presence of known hepatocyte dysfunction or bile ductal abnormalities such as intrahepatic cholestasis, primary biliary cirrhosis or sclerosing cholangitis * Inability to adhere to treatment and visit schedule * Female participants who are pregnant * Female participants who are breast feeding * Female participants who are using estrogen-containing compounds and cannot/will not discontinue them for the duration of the study * Female participants of childbearing potential who are not using locally approved birth control method(s) or double barrier contraception (ie, condom and diaphragm, condom or diaphragm and spermicidal gel or foam) * Taking any of the following medications: bile acid products; inhibitors of bile acid transporters; bile acid binding resins; aluminum-based antacids; coumarin and its derivatives; cholestyramine; ciclosporin; sirolimus; or phenobarbital