ABCMdb

ABCB4 p.Leu1082Gln

Predicted by SNAP2:	A: D (63%), C: N (53%), D: D (85%), E: D (80%), F: D (66%), G: D (80%), H: D (80%), I: N (78%), K: D (80%), M: N (66%), N: D (80%), P: D (85%), Q: D (75%), R: D (80%), S: D (75%), T: D (66%), V: N (66%), W: D (80%), Y: D (75%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: N, K: D, M: N, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D,

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[hide] Mutations and polymorphisms in the bile salt expor... Pharmacogenet Genomics. 2007 Jan;17(1):47-60. Lang C, Meier Y, Stieger B, Beuers U, Lang T, Kerb R, Kullak-Ublick GA, Meier PJ, Pauli-Magnus C
Mutations and polymorphisms in the bile salt export pump and the multidrug resistance protein 3 associated with drug-induced liver injury.
Pharmacogenet Genomics. 2007 Jan;17(1):47-60., [PMID:17264802]

Abstract [show]
OBJECTIVES: Increasing evidence suggests that a genetically determined functional impairment of the hepatocellular efflux transporters bile salt export pump (BSEP, ABCB11) and multidrug resistance protein 3 (MDR3, ABCB4) play a pathophysiological role in the development of drug-induced liver injury. The aim of this study was therefore to describe the extent of genetic variability in ABCB11 and ABCB4 in patients with drug-induced liver injury and to in vitro functionally characterize newly detected ABCB11 mutations and polymorphisms. METHODS: ABCB11 and ABCB4 were sequenced in 23 patients with drug-induced cholestasis and 13 patients with drug-induced hepatocellular injury. Ninety-five healthy Caucasians served as the control group. Reference and mutant BSEP were expressed in Sf9 cells and ATP-dependent transport of [H]-taurocholate was measured in a rapid filtration assay. RESULTS: Four highly conserved nonsynonymous mutations were specific for drug-induced liver injury [ABCB11: D676Y (drug-induced cholestasis) and G855R (drug-induced cholestasis); ABCB4: I764L (drug-induced cholestasis) and L1082Q (drug-induced hepatocellular injury)]. Furthermore, a polymorphism in exon 13 of ABCB11 (V444A), which is associated with decreased hepatic BSEP expression was significantly more frequent in drug-induced cholestasis patients than in drug-induced hepatocellular injury patients and healthy controls (76 versus 50 and 59% in drug-induced cholestasis patients, drug-induced hepatocellular injury patients and healthy controls, respectively; P<0.05). The in-vitro transport activity of the V444A and the D676Y BSEP constructs was similar, whereas the G855R mutation was nonfunctional. CONCLUSION: In summary, our data support a role of ABCB11 and ABCB4 mutations and polymorphisms in drug-induced cholestasis. Genotyping of selected patients with acquired cholestasis might help to identify individuals with a genetic predisposition.

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No. Sentence Comment
5 Results Four highly conserved nonsynonymous mutations were specific for drug-induced liver injury [ABCB11: D676Y (drug-induced cholestasis) and G855R (drug-induced cholestasis); ABCB4: I764L (drug-induced cholestasis) and L1082Q (drug-induced hepatocellular injury)]. Login to comment
150 Six variant sites were specific for patients with drug-induced liver injury, including three intronic and three coding region changes (synonymous: exon 12: 1314G > A; nonsynonymous: exon 18: 2290A > C-I764L and exon 25: 3245T > A-L1082Q). Login to comment
152 18) and the L1082Q mutation in a patient with DH taking amoxicillin/clavulanic acid (no. Login to comment
163 The estimated IC50 was 50 and 60 mmol/l for reference BSEP Fig. 4 Extracellular I764L T175A R652G R590Q Cytoplasm L1082Q Secondary structure of multidrug resistance protein 3 (MDR3) with nonsynonymous coding region variants. Login to comment
203 The L1082Q site was encountered in a heterozygous patient with amoxicillin/clavulanic acid-induced hepatocellular injury. Login to comment

[hide] Tacrine-induced liver damage: an analysis of 19 ca... Pharmacogenet Genomics. 2007 Dec;17(12):1091-100. Alfirevic A, Mills T, Carr D, Barratt BJ, Jawaid A, Sherwood J, Smith JC, Tugwood J, Hartkoorn R, Owen A, Park KB, Pirmohamed M
Tacrine-induced liver damage: an analysis of 19 candidate genes.
Pharmacogenet Genomics. 2007 Dec;17(12):1091-100., [PMID:18004213]

Abstract [show]
OBJECTIVES: Tacrine, the first acetylcholinesterase inhibitor used in the treatment of Alzheimer's disease, is associated with transaminase elevation in up to 50% of patients. The mechanism of tacrine-induced liver damage is not fully understood, but earlier studies have suggested that genetic factors may play a role. Our aim was to investigate whether single-nucleotide polymorphisms (SNPs) in 19 candidate genes were associated with tacrine-induced liver damage. METHODS: Sixty-nine patients of Caucasian origin treated with tacrine for Alzheimer's disease were investigated by genotyping 241 SNPs in 19 candidate genes potentially related to hepatotoxicity. The association with ABCB4 [which encodes MultiDrug Resistance Protein 3 (MDR3)] was explored in transepithelial transport studies using the ABCB4-transfected pig kidney epithelial cell line (LLC-PK1). RESULTS: The strongest association between alanine aminotransferase levels and three SNPs within ATP-binding cassette, subfamily B (MDR/TAP), member 4 (ABCB4) (uncorrected P=0.0005) was not significant after adjusting for multiple testing. No association was demonstrated with ATP-binding cassette, subfamily B (MDR/TAP), member 1 (ABCB1) or carnitine O-octanoyltransferase (CROT) which are located adjacent to ABCB4. Using the transepithelial transport system we failed to show a difference in tacrine accumulation between ABCB4-transfected and parental cell lines. The association with ABCB4 warrants further testing using either another population and/or functional studies.

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196 Two ABCB4 nonsynonymous SNPs (I764L and L1082Q) were specific for drug-induced cholestasis and hepatocellular injury, respectively. Login to comment