Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disorder caused by mutations in the CYP27A1 gene creating dysfunctional bile acid metabolism, afflicting patients with a progressive disarray of symptoms including but not limited to: ataxia, dementia, epilepsy, tendon xanthomas and cataracts. The gene discussed is CYP27A1; the disease is cerebrotendinous xanthomatosis.