Cerebrotendinous xanthomatosis is a rare autosomal (2q33-qter) recessive disorder of the formation of chenodeoxycholic acid from cholesterol, owing to a deficiency in sterol 27-hydroxylase. The disease causes enhanced conversion of cholesterol into cholestanol. Both sterols are deposited in various tissues.
The disease manifests mostly in adolescence. In addition to xanthomas, cataracts, and chronic diarrhea, the neurological symptoms include impaired psychomotor development, decline in intelligence, mental deterioration, extrapyramidal symptoms, ataxia, expressive dysphasia, spastic paresis, or peripheral neuropathy. Since this disease can be treated by administering chenodeoxycholic acid, it is essential to diagnose it early.
Cranial MRI shows changes in the basal ganglia and in the white matter. Laboratory analysis reveals elevated cholestanol levels in the plasma (determination by gas-liquid chromatography) (Moghadasian et al., 2002).