The authors report the clinical findings in 10 Italian cases of cerebrotendinous xanthomatosis (CTX). In addition to the classical neurological manifestations, the presence of psychiatric symptoms and osteopenia is stressed. Chronic treatment with chenodeoxycholic acid resulted in decreased plasma cholestanol levels and improvement of some central and peripheral neurophysiological parameters including EEG, VEP, SEP and conduction velocities. Due to the presence of cataracts, ischemic heart disease, premature atherosclerosis, mental deterioration and osteoporosis, usually found in old age, CTX can be considered a useful model of premature ageing.