A novel bile acid biosynthesis defect due to a deficiency of peroxisomal ABCD3.

Human molecular genetics 2015 Jan 15

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ABCD3 is one of three ATP-binding cassette (ABC) transporters present in the peroxisomal membrane catalyzing ATP-dependent transport of substrates for metabolic pathways localized in peroxisomes. So far, the precise function of ABCD3 is not known. Here, we report the identification of the first patient with a defect of ABCD3. The patient presented with hepatosplenomegaly and severe liver disease and showed a striking accumulation of peroxisomal C27-bile acid intermediates in plasma. Investigation of peroxisomal parameters in skin fibroblasts revealed a reduced number of enlarged import-competent peroxisomes. Peroxisomal beta-oxidation of C26:0 was normal, but beta-oxidation of pristanic acid was reduced. Genetic analysis revealed a homozygous deletion at the DNA level of 1758bp, predicted to result in a truncated ABCD3 protein lacking the C-terminal 24 amino acids (p.Y635NfsX1). Liver disease progressed and the patient required liver transplantation at 4 years of age but expired shortly after transplantation. To corroborate our findings in the patient, we studied a previously generated Abcd3 knockout mouse model. Abcd3-/- mice accumulated the branched chain fatty acid phytanic acid after phytol loading. In addition, analysis of bile acids revealed a reduction of C24 bile acids, whereas C27-bile acid intermediates were significantly increased in liver, bile and intestine of Abcd3-/- mice. Thus, both in the patient and in Abcd3-/- mice, there was evidence of a bile acid biosynthesis defect. In conclusion, our studies show that ABCD3 is involved in transport of branched-chain fatty acids and C27 bile acids into the peroxisome and that this is a crucial step in bile acid biosynthesis. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Citation

Sacha Ferdinandusse, Gerardo Jimenez-Sanchez, Janet Koster, Simone Denis, Carlo W Van Roermund, Irma Silva-Zolezzi, Ann B Moser, Wouter F Visser, Mine Gulluoglu, Ozlem Durmaz, Mubeccel Demirkol, Hans R Waterham, Gülden Gökcay, Ronald J A Wanders, David Valle. A novel bile acid biosynthesis defect due to a deficiency of peroxisomal ABCD3. Human molecular genetics. 2015 Jan 15;24(2):361-70