A Case Study of Cerebrotendinous Xanthomatosis with a High Concentration of Serum Bile Acids

This case involves a patient with tendon xanthomas, pyramidal symptoms, and mild mental retardation. She is a 58-year-old housewife who was admitted to our hospital because of pain in both Achilles tendons. Upon examination, she was found to have normocholesterolemia with increased cholestanol concentrations in the serum, bile and xanthomas. There also appears to have been bile alcohol, an increased ratio of cholic acid to chenodeoxy cholic acid in the serum and bile, and an increased 7α-hydroxycholesterol concentration in the serum. We diagnosed her as having cerebrotendinous xanthomatosis (CTX). However, the bile acid content in the serum was unusually high in this case, despite the congenital nature of the defect in the synthesis of bile acids. Although no remarkable abnormality was found in a liver biopsy specimen or in the blood chemistry, a decreased movement of bile acids from the serum was suspected because of the results obtained from a bile acid tolerance test. The ramifications of this finding regarding the symptoms of CTX are interesting.