BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) is characterised by troublesome maternal pruritus, raised serum bile acid levels and increased fetal risk. Mutations of the ABCB4 gene encoding the hepatobiliary phospholipid transporter have been identified in a small proportion of patients with cholestasis of pregnancy. In a recent prospective study on 693 patients with cholestasis of pregnancy, a cut-off level for serum bile acid (> or =40 micromol/l) was determined for increased risk of fetal complications. OBJECTIVES: To investigate whether common combinations of polymorphic alleles (haplotypes) of the genes encoding the hepatobiliary ATP-binding cassette (ABC) transporters for phospholipids (ABCB4) and bile acids (ABCB11) were associated with this severe form of cholestasis of pregnancy. METHODS: For genetic analysis, 52 women with bile acid levels > or =40 micromol/l (called cases) and 52 unaffected women (called controls) matched for age, parity and geographical residence were studied. Gene variants tagging common ABCB4 and ABCB11 haplotypes were genotyped and haplotype distributions were compared between cases and controls by permutation testing. RESULTS: In contrast with ABCB11 haplotypes, ABCB4 haplotypes differed between the two groups (p = 0.019), showing that the severe form of cholestasis of pregnancy is associated with the ABCB4 gene variants. Specifically, haplotype ABCB4_5 occurred more often in cases, whereas haplotypes ABCB4_3 and ABCB4_7 were more common in controls. These associations were reflected by different frequencies of at-risk alleles of the two tagging polymorphisms (c.711A: odds ratio (OR) 2.27, p = 0.04; deletion intron 5: OR 14.68, p = 0.012). CONCLUSION: Variants of ABCB4 represent genetic risk factors for the severe form of ICP in Sweden.
BACKGROUND:Intrahepatic cholestasis of pregnancy (ICP) is characterised by troublesome maternal pruritus, raised serum bile acid levels and increased fetal risk. Mutations of the ABCB4 gene encoding the hepatobiliary phospholipid transporter have been identified in a small proportion of patients with cholestasis of pregnancy. In a recent prospective study on 693 patients with cholestasis of pregnancy, a cut-off level for serum bile acid (> or =40 micromol/l) was determined for increased risk of fetal complications. OBJECTIVES: To investigate whether common combinations of polymorphic alleles (haplotypes) of the genes encoding the hepatobiliary ATP-binding cassette (ABC) transporters for phospholipids (ABCB4) and bile acids (ABCB11) were associated with this severe form of cholestasis of pregnancy. METHODS: For genetic analysis, 52 women with bile acid levels > or =40 micromol/l (called cases) and 52 unaffected women (called controls) matched for age, parity and geographical residence were studied. Gene variants tagging common ABCB4 and ABCB11 haplotypes were genotyped and haplotype distributions were compared between cases and controls by permutation testing. RESULTS: In contrast with ABCB11 haplotypes, ABCB4 haplotypes differed between the two groups (p = 0.019), showing that the severe form of cholestasis of pregnancy is associated with the ABCB4 gene variants. Specifically, haplotype ABCB4_5 occurred more often in cases, whereas haplotypes ABCB4_3 and ABCB4_7 were more common in controls. These associations were reflected by different frequencies of at-risk alleles of the two tagging polymorphisms (c.711A: odds ratio (OR) 2.27, p = 0.04; deletion intron 5: OR 14.68, p = 0.012). CONCLUSION: Variants of ABCB4 represent genetic risk factors for the severe form of ICP in Sweden.
Authors: E Jacquemin; J M De Vree; D Cresteil; E M Sokal; E Sturm; M Dumont; G L Scheffer; M Paul; M Burdelski; P J Bosma; O Bernard; M Hadchouel; R P Elferink Journal: Gastroenterology Date: 2001-05 Impact factor: 22.682
Authors: R Müllenbach; A Bennett; N Tetlow; N Patel; G Hamilton; F Cheng; J Chambers; R Howard; S D Taylor-Robinson; C Williamson Journal: Gut Date: 2005-06 Impact factor: 23.059
Authors: Ruta Valentonyte; Jochen Hampe; Klaus Huse; Philip Rosenstiel; Mario Albrecht; Annette Stenzel; Marion Nagy; Karoline I Gaede; Andre Franke; Robert Haesler; Andreas Koch; Thomas Lengauer; Dirk Seegert; Norbert Reiling; Stefan Ehlers; Eberhard Schwinger; Matthias Platzer; Michael Krawczak; Joachim Müller-Quernheim; Manfred Schürmann; Stefan Schreiber Journal: Nat Genet Date: 2005-02-27 Impact factor: 38.330
Authors: P H Dixon; N Weerasekera; K J Linton; O Donaldson; J Chambers; E Egginton; J Weaver; C Nelson-Piercy; M de Swiet; G Warnes; E Elias; C F Higgins; D G Johnston; M I McCarthy; C Williamson Journal: Hum Mol Genet Date: 2000-05-01 Impact factor: 6.150
Authors: Shadi Abu-Hayyeh; Pablo Martinez-Becerra; Siti H Sheikh Abdul Kadir; Clare Selden; Marta R Romero; Myrddin Rees; Hanns-Ulrich Marschall; Jose J G Marin; Catherine Williamson Journal: J Biol Chem Date: 2010-02-20 Impact factor: 5.157