Identification of unusual 7-oxygenated bile acid sulfates in a patient with Niemann-Pick disease, type C

Abstract

Niemann-Pick disease, type C, was diagnosed in a 3-month-old boy with hepatosplenomegaly, mild signs of cholestasis, hepatic inflammation and extramedullary erythropoiesis, together with chronic airway disease. He developed muscular hypotonia, psychomotor retardation, rickets, and signs of peripheral neuropathy. The patient was found to excrete abnormal amounts of unusual bile acids in urine at 3 and 5 months of age. These acids were shown to have a 3beta-hydroxy-Delta(5) structure and to carry an oxo or hydroxy group at C-7. They were sulfated at C-3 and nonamidated or conjugated with glycine or taurine at C-24. Part of the 7-hydroxy acids, presumably the 7beta-hydroxylated one, was also conjugated with N-acetylhexosamine, probably N-acetylglucosamine, at the 7-hydroxy group. Possible metabolic pathways for the formation of the 7-oxo and 7beta-hydroxycholenoic acids are discussed. Based on previous data concerning the effects of 3beta-hydroxy-Delta(5) bile acids on bile acid transport, it is suggested that the formation of such bile acids is responsible for the cholestasis in this patient.