The first cerebrotendinous xanthomatosis family from Argentina: a new mutation in CYP27A1 gene.

Cerebrotendinous xanthomatosis (CTX) is a treatable, autosomal recessive, lipid storage disorder characterized by diarrhea and cataracts, usually appearing in the first decade of life, followed by growth of tendon xanthomas and progressive neurologic disability.1 The typical brain findings include MRI signal abnormalities mainly in the globus pallidus and dentate nuclei.2 The disease is caused by deficiency of the mitochondrial enzyme, sterol 27-hydroxylase, resulting in impaired primary bile acid synthesis, decreased chenodeoxycholic acid production, and cholestanol accumulation in virtually every tissue.3 The main blood chemistry abnormalities include high plasma levels of cholestanol with normal to low cholesterol. Different mutations of the CYP27A1 gene have been described.4 Early diagnosis is crucial as treatment with chenodeoxycholic acid (CDCA) may improve symptoms.5 Here we report the cases of two Argentinian siblings with a novel mutation of the CYP27A1 gene associated with clinical variants, including absence of tendon xanthomas.