BACKGROUND/AIMS: Inherited dysfunction of the bile salt export pump BSEP (ABCB11) causes a progressive and a benign form of familial intrahepatic cholestasis, denominated as PFIC2 and BRIC2, respectively. We functionally characterized novel ABCB11 mutations encountered in two patients with a PFIC2 and a BRIC2 phenotype, respectively. METHODS: BSEP expression was determined in liver biopsies by immunohistochemistry. ABCB11 mutations were functionally characterized by taurocholate transport in SF9 cells transfected with human ABCB11. RESULTS: The PFIC2 patient was compound heterozygous for a splicing mutation in intron 4 ((+3)A > C) combined with an early stop codon at position 930 (R930X), while the BRIC2 patient was compound heterozygous for two nonsynonymous mutations in exon 9 (E297G) and exon 12 (R432T), respectively. Hepatic BSEP expression was absent in PFIC2 and preserved in BRIC2. In BRIC2, taurocholate transport was decreased to 13% and 20% of reference levels for R432T and E297G, respectively. CONCLUSIONS: The intron 4 (+3)A > C, R930X and R432T represent previously undescribed mutations of the ABCB11 gene that confer a PFIC2 and a BRIC2 phenotype, respectively. By combining functional in-vitro characterization with immunohistochemical detection of variant BSEP we provide direct evidence for the role of ABCB11 mutations in the pathogenesis of different forms of intrahepatic cholestasis.
BACKGROUND/AIMS: Inherited dysfunction of the bile salt export pump BSEP (ABCB11) causes a progressive and a benign form of familial intrahepatic cholestasis, denominated as PFIC2 and BRIC2, respectively. We functionally characterized novel ABCB11 mutations encountered in two patients with a PFIC2 and a BRIC2 phenotype, respectively. METHODS:BSEP expression was determined in liver biopsies by immunohistochemistry. ABCB11 mutations were functionally characterized by taurocholate transport in SF9 cells transfected with humanABCB11. RESULTS: The PFIC2patient was compound heterozygous for a splicing mutation in intron 4 ((+3)A > C) combined with an early stop codon at position 930 (R930X), while the BRIC2patient was compound heterozygous for two nonsynonymous mutations in exon 9 (E297G) and exon 12 (R432T), respectively. Hepatic BSEP expression was absent in PFIC2 and preserved in BRIC2. In BRIC2, taurocholate transport was decreased to 13% and 20% of reference levels for R432T and E297G, respectively. CONCLUSIONS: The intron 4 (+3)A > C, R930X and R432T represent previously undescribed mutations of the ABCB11 gene that confer a PFIC2 and a BRIC2 phenotype, respectively. By combining functional in-vitro characterization with immunohistochemical detection of variant BSEP we provide direct evidence for the role of ABCB11 mutations in the pathogenesis of different forms of intrahepatic cholestasis.
Authors: Ludmila Pawlikowska; Sandra Strautnieks; Irena Jankowska; Piotr Czubkowski; Karan Emerick; Anthony Antoniou; Catherine Wanty; Bjorn Fischler; Emmanuel Jacquemin; Sami Wali; Samra Blanchard; Inge-Merete Nielsen; Billy Bourke; Shirley McQuaid; Florence Lacaille; Jane A Byrne; Albertien M van Eerde; Kaija-Leena Kolho; Leo Klomp; Roderick Houwen; Peter Bacchetti; Steven Lobritto; Vera Hupertz; Patricia McClean; Giorgina Mieli-Vergani; Benjamin Shneider; Antal Nemeth; Etienne Sokal; Nelson B Freimer; A S Knisely; Philip Rosenthal; Peter F Whitington; Joanna Pawlowska; Richard J Thompson; Laura N Bull Journal: J Hepatol Date: 2010-04-13 Impact factor: 25.083
Authors: Kimberley Evason; Kevin E Bove; Milton J Finegold; A S Knisely; Sue Rhee; Philip Rosenthal; Alexander G Miethke; Saul J Karpen; Linda D Ferrell; Grace E Kim Journal: Am J Surg Pathol Date: 2011-05 Impact factor: 6.394
Authors: Richard H Ho; Brenda F Leake; Dawn M Kilkenny; Henriette E Meyer Zu Schwabedissen; Hartmut Glaeser; Deanna L Kroetz; Richard B Kim Journal: Pharmacogenet Genomics Date: 2010-01 Impact factor: 2.089
Authors: Gabriella Andreotti; Idan Menashe; Jinbo Chen; Shih-Chen Chang; Asif Rashid; Yu-Tang Gao; Tian-Quan Han; Lori C Sakoda; Stephen Chanock; Philip S Rosenberg; Ann W Hsing Journal: Eur J Epidemiol Date: 2009-11-04 Impact factor: 8.082