Cerebrotendinous Xanthomatosis (CTX; OMIM #213700) is a rare lipid storage metabolic disease with autosomal recessive inheritance. It is characterised by deficiency of mitochondrial sterol 27-hydroxylase (CYP27) which is a key enzyme in bile acid biosynthesis. The enzyme converts cholesterol into bile acids, hence deficiency results in abnormal deposition of cholesterol and cholestenol in multiple tissues. The defect in CTX is located on CYP27A1 gene localised on the long arm of chromosome 2 .
Van Bogaert and colleagues first described CTX in 1937 . It is estimated to occur in 3-5 out of 100,000 individuals worldwide and is more commonly seen in the Moroccan Jewish population with an incidence of 1 in 108 individuals in that group. It is also commoner in the Druze population in Israel with incidence of 1:440.