Cerebrotendinous xanthomatosis (CTX) is a rare recessive disorder believed to be exclusively caused by mutations in the CYP27A1 gene coding for the enzyme sterol 27-hydroxylase. The disease is characterized by tendon xanthomas, juvenile cataract, progressive dementia, chronic diarrhea, osteoporosis, ataxia and premature atherosclerosis. Xanthomas also often occur in the brain, in particular in cerebellum (1). This article is protected by copyright. All rights reserved.