A case of cerebrotendinous xanthomatosis: effects of ursodeoxycholic acid administration on serum bile acids and cholestanol.

Cerebrotendinous xanthomatosis (CTX) is a rare familiar disease characterized by tendon xanthomas, cataracts, cerebellar ataxia, dementia and an elevated serum cholestanol level. In this paper, a 50-year-old man with typical signs and symptoms of CTX is described. Serum cholestanol and chelesterol concentrations were 17.9-28.6 micrograms/ml and 109-153 mg/dl, respectively. The determination of non-sulfated bile acid concentration in the serum assayed by mass fragmentography disclosed an abnormal profile. The concentration of cholic acid (0.30-0.52 microgram/ml) was higher than normal, while those of chenodeoxycholic acid, ursodeoxycholic acid, deoxycholic acid and lithocholic acid were extremely low or undetectable. Administration of ursodeoxycholic acid (300 mg per day, orally) for 2 weeks resulted in a marked reduction of serum cholic acid concentration. However, serum cholestanol levels remained unchanged.