ABCMdb

ABCC2 p.Trp709Arg

Predicted by SNAP2:	A: D (91%), C: D (80%), D: D (95%), E: D (95%), F: D (75%), G: D (95%), H: D (91%), I: D (91%), K: D (95%), L: D (91%), M: D (80%), N: D (95%), P: D (95%), Q: D (91%), R: D (91%), S: D (95%), T: D (95%), V: D (85%), Y: D (80%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, Y: D,

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[hide] Pharmacogenomics of MRP transporters (ABCC1-5) and... Drug Metab Rev. 2008;40(2):317-54. Gradhand U, Kim RB
Pharmacogenomics of MRP transporters (ABCC1-5) and BCRP (ABCG2).
Drug Metab Rev. 2008;40(2):317-54., [PMID:18464048]

Abstract [show]
Elucidation of the key mechanisms that confer interindividual differences in drug response remains an important focus of drug disposition and clinical pharmacology research. We now know both environmental and host genetic factors contribute to the apparent variability in drug efficacy or in some cases, toxicity. In addition to the widely studied and recognized genes involved in the metabolism of drugs in clinical use today, we now recognize that membrane-bound proteins, broadly referred to as transporters, may be equally as important to the disposition of a substrate drug, and that genetic variation in drug transporter genes may be a major contributor of the apparent intersubject variation in drug response, both in terms of attained plasma and tissue drug level at target sites of action. Of particular relevance to drug disposition are members of the ATP Binding Cassette (ABC) superfamily of efflux transporters. In this review a comprehensive assessment and annotation of recent findings in relation to genetic variation in the Multidrug Resistance Proteins 1-5 (ABCC1-5) and Breast Cancer Resistance Protein (ABCG2) are described, with particular emphasis on the impact of such transporter genetic variation to drug disposition or efficacy.

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101 Several molecular defects in MRP2 have been suggested to result in DJS including those which produce deficient protein maturation (Hashimoto et al., 2002; Keitel et al., 2003), proteasomal degradation (Keitel, 2003), impaired membrane sorting (Hashimoto et al., 2002; Mor-Cohen et al., 2001), loss in transport activity (Mor-Cohen et al., 2001), Figure 2 Predicted membrance topology of MRP2 (ABCC2) based on hydrophobicity analysis. Locations of the non-synonymous polymorphisms are indicated with arrows. See Table 2 for allele frequencies and description of funtional consequences. NH2 COOH NBD NBD in out Membrane Pro19Leu Phe39Tyr Arg100* Arg100Gln Ser281Asn Ser325* Asp333Gly Arg353His Arg412Gly Val417Ile Lys430Arg Thr486Ile Gly676Arg Trp709Arg Asn718Ser Ser789Phe Arg768Trp Asp833Asn Glu893Gln Leu927Arg Lys961Arg Tyr967* Phe981Leu Gln1019His Arg1066* Arg1150His Arg1100Cys Arg1100His Ile1137Phe Ile1173Phe Val1188Glu Arg1174His Arg1181Leu Asn1244Lys Thr1273Ala Pro1291Leu Lys1299Gln Arg1310* Ser1367Cys Gln1382Arg Arg1392del Met1393del Ala1450Thr Thr1476Met Cys1515Tyr MRP2 (ABCC2) NBD NBD Asp833Asn Glu893Gln Leu927Arg Lys961Arg Tyr967* NBD NBDNBD Asp833Asn Glu893Gln Leu927Arg Lys961Arg Tyr967* 325 Table2MRP2(ABCC2)singlenucleotidepolymorphisms.Location,allelefrequencyandfunctionaleffects. Positionin codingsequence Amino acidexchangeLocation Allelefrequency EffectNCBIIDReferenceAfCaJpothers 56C>TPro19LeuExon2--1[1]b -- 116T>APhe39TyrExon2--0[2]--rs927344 298C>TArg100*Exon3--[3]-DJS[3] 299G>AArg100GlnExon3--1[1]b -- 842G>ASer281AsnExon7-0[4]1[1]b -- 974C>GSer325*Exon8---Malayan[5]DJS[5] 998A>GAsp333GlyExon8--0[2]--rs17222674 1058G>AArg353HisExon9--0[2]--rs7080681 1271A>GArg412GlyExon10-[6]0[2]-DJS;Decreaseinmethotrexateelimination[6] 1249G>AVal417IleExon10-22[7]13[9]-lowermRNAand(protein)expressioninpreterm placenta[11] rs2273697 26[8]16[4]noeffectonRNAandproteinininduodenum[12] 19[10]noeffectonproteininliver[8] noeffectonconjugatedbilirubinlevelinserum[13] changesinlocalizationinneuroepithelialtumors[14] possibleassociationwithtenofovir-inducedrenal proximaltubulopathy[15] 1289A>GLys430ArgExon10-4[16]0[2]-- 1457C>TThr486IleExon10-0[4]3[1]b -- 2026G>CGly676Arg--0[2]-DJS[17] 2125T>CTrp709Arg--0[2]-DJS[17] 2153A>GAsn718SerExon17-0[4]0[2]--rs3740072 2302C>TArg768TrpExon18-0[18]1[9]-DJS;deficientmaturationandimpairedsorting[19] 2366C>TSer789PheExon18-0[18]1[9]-lowerexpressionandmembranelocalization[20] noeffectonconjugatedbilirubinlevelinserum[13]/ heterozygous 2647G>AAsp883AsnExon20--1[1]b -- 2677G>CGlu893GlnExon20--0[2]--rs3740071 2780T>GLeu927ArgExon21-1[10]0[2]-- (Continued) Table2(Continued) Positionin codingsequence Aminoacid exchangeLocation Allelefrequency EffectNCBIIDReferenceAfCaJpothers 2882A>GLys961ArgExon21--1[1]b --- 2901C>ATyr967*Exon22--0[2]--rs17222547 2943C>GPhe981LeuExon22-2[21]0[2]-Noinfluenceonpravastatinkinetics[21] 3057G>TGln1019HisExon22--1[1]b -- 3196C>TArg1066*Exon23-[22]0[2]-DJS;truncatedprotein[22][23] 3298C>TArg1100CysExon24-1[10]0[2]-- 3299G>AArg1100HisExon24-1[10]0[2]-- 3449G>AArg1150HisExon25--0[2]Israeli[24]DJS;impairedtransportactivityintransfectedcells althoughnormalexpressionandlocalization[24] 3517A>TIle1173PheExon25--0[2]Israeli[24]DJS;impairedproteinmaturationandproteasomal degradation[25] lowexpression,mislocation,andimpairedtransport activityintransfectedcells[24] 3521G>AArg1174HisExon25-0[4]1[1]b -- 3542G>TArg1181LeuExon25-0[4]0[2]--rs8187692 3563T>AVal1188GluExon25-7[4]1[1]b -noeffectonnelfinaviraccumulationinPBMC[4],rs17222723 4[16]associatedwithanthracycline-induced cardiotoxicity[26] 6[8] 3732C>TAsn1244LysExon26--0[1]b -- 0[2] 3817A>GThr1273AlaExon27--0[2]--rs8187699 3872C>TPro1291LeuExon28--0[2]--rs17216317 3897A>CLys1299GlnExon28--0[2]--rs4148400 3928C>TArg1310*Exon28--0[2]-DJS[17,27] 4100C>GSer1367CysExon29--1[1]b -- 4145A>GGln1382ArgExon29--[28]-DJS;noeffectonmaturationorsorting,impaired substrate-inducedATPhydrolysis[19] 4175-80delArg1392delExon30--0[2]-DJS;deficientMRP2maturationandimpaired sortingtoapicalmembraneintransfectedcells[29] 327 4348G>AAla11450ThrExon31-0[18]1[9]-lowerexperssionandmembracelocalizationin transfectedcells[20] 4461C>TThr1476MetExon31-[30]1[2]-- 4544G>ACys1515TyrExon32-9[4]1[1]b -noeffectonnelfinaviraccumulationinPBMC[4]rs8187710 5[10]associatedwithanthracycline-induced cardiotoxicity[26] 4[16] 6[8] ReferencewithoutfrequencymeansthatSNPwasdetectedbutnofrequencydetermined. Login to comment

[hide] Mutational analysis of ABCC2 gene in two siblings ... Clin Genet. 2010 Dec;78(6):598-600. doi: 10.1111/j.1399-0004.2010.01497.x. Pacifico L, Carducci C, Poggiogalle E, Caravona F, Antonozzi I, Chiesa C, Maggiore G
Mutational analysis of ABCC2 gene in two siblings with neonatal-onset Dubin Johnson syndrome.
Clin Genet. 2010 Dec;78(6):598-600. doi: 10.1111/j.1399-0004.2010.01497.x., [PMID:21044052]

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28 The study of allelic segregation in Letter to the Editor R100X R393W IVS6_IVS7del L441M IVS13 +2 T>A IVS15 +2 T>C G676R IVS18 +2 T>C R768W * 2748_2883del * R1066X * 3399_3400del L1173F 3615_3843del* Y1275X * R1310X Q1382R R1392_M1393del S325X W709R T1273A IVS8 +4 A>G 1256_1272delins CT 4292_4293delR1150H E1352Q * Exon 1 32 Fig. 1. Login to comment

[hide] Genetic background of Japanese patients with adult... Hepatol Res. 2007 Oct;37(10):777-83. Epub 2007 May 22. Hayashi H, Wakusawa S, Yano M, Okada T
Genetic background of Japanese patients with adult-onset storage diseases in the liver.
Hepatol Res. 2007 Oct;37(10):777-83. Epub 2007 May 22., [PMID:17517077]

Abstract [show]
In contrast to primary lysosomal diseases in young subjects, adult-onset liver storage disorders may be explained by non-lysosomal genetic defects. The aim of the present review is to summarize the genetic backgrounds of Japanese patients with hemochromatosis of unknown etiology, Wilson disease of primary copper toxicosis, and the black liver of Dubin-Johnson syndrome. Three patients with middle-age onset hemochromatosis were homozygous for mutations of HJV and two patients were homozygous for mutations of TFR2. Minor genes other than HJV and TFR2 might be involved in Japanese patients. Five of the six patients with Wilson disease were compound heterozygous, while the remaining patient was heterozygous for the mutation in ATP7B responsible for copper toxicosis. Involvement of MURR1 was not proved in the heterozygote of ATP7B. Because of ferroxidase deficiency,most patients had secondary lysosomes shared by cuprothioneins and iron complex. Six patients with Dubin-Johnson syndrome were homozygous or compound heterozygous for mutant MRP2. Despite complex metabolic disorders, the syndrome had a single genetic background. Thus, most patients with adult-onset lysosomal proliferation in the liver had genetic defects in non-lysosomal organelles, named the secondary lysosomal diseases. The proliferating lysosomes in these conditions seemed to be heterogeneous in their matrices.

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64 They included the three mutations 1177C > T (R393W), 2026G > C (G676R) and 2125T > C (W709R) first found in our patients.23,49,52 Better understanding of the pathogenesis of hepatic storage disorders provided by gene analysis The genetic backgrounds of Japanese patients with hemochromatosis are now partially clear. Login to comment
76 Fifty years after the first identification of lysosomes,1,2 three Table 3 Results of mutation analysis for patients with Dubin-Johnson syndrome Patient Age (years)/Sex MRP2 Mutation 1 Mutation 2 1 21/male 298C > T (R100X) 298C > T (R100X) 2 26/male 1177C > T (R393W) 2302C > T (R768W) 3 23/female 1967 + 2T > C (1901del67: exon 15 skipping) 1967 + 2T > C (1901del67: exon 15 skipping) 4 25/male 1967 + 2T > C (1901del67: exon 15 skipping) 2026G > C (G676R) 5 28/female 2125T > C (W709R) 2125T > C (W709R) 6 28/male 2439 + 2T > C (2272del168: exon 18 skipping) 2439 + 2T > C (2272del168: exon 18 skipping) adult-onset storage disorders of the liver were found to be secondary lysosomal diseases with the genetic defects outside of lysosomes. Login to comment

[hide] The apical conjugate efflux pump ABCC2 (MRP2). Pflugers Arch. 2007 Feb;453(5):643-59. Epub 2006 Jul 18. Nies AT, Keppler D
The apical conjugate efflux pump ABCC2 (MRP2).
Pflugers Arch. 2007 Feb;453(5):643-59. Epub 2006 Jul 18., [PMID:16847695]

Abstract [show]
ABCC2 is a member of the multidrug resistance protein subfamily localized exclusively to the apical membrane domain of polarized cells, such as hepatocytes, renal proximal tubule epithelia, and intestinal epithelia. This localization supports the function of ABCC2 in the terminal excretion and detoxification of endogenous and xenobiotic organic anions, particularly in the unidirectional efflux of substances conjugated with glutathione, glucuronate, or sulfate, as exemplified by leukotriene C(4), bilirubin glucuronosides, and some steroid sulfates. The hepatic ABCC2 pump contributes to the driving forces of bile flow. Acquired or hereditary deficiency of ABCC2, the latter known as Dubin-Johnson syndrome in humans, causes an increased concentration of bilirubin glucuronosides in blood because of their efflux from hepatocytes via the basolateral ABCC3, which compensates for the deficiency in ABCC2-mediated apical efflux. In this article we provide an overview on the molecular characteristics of ABCC2 and its expression in various tissues and species. We discuss the transcriptional and posttranscriptional regulation of ABCC2 and review approaches to the functional analysis providing information on its substrate specificity. A comprehensive list of sequence variants in the human ABCC2 gene summarizes predicted and proven functional consequences, including variants leading to Dubin-Johnson syndrome.

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139 Although all sequence variants associated with Dubin-Johnson syndrome result in the absence of a Table 3 Nucleotide sequence variants in the human ABCC2 gene (NM_000392) leading to amino acid changes in the ABCC2/MRP2 protein (NP_000383) Location Nucleotide changea Deduced effect on proteina Causing Dubin-Johnson syndromeb Predicted effect by PolyPhen databasec Experimentally proven functional consequence Average frequency of indicated nucleotide exchange in population NCBI SNP IDd and/or references Exon 2 c.56 C>Te p.P19L Probably damaging T: 0.007 [63] Exon 2 c.116 T>A p.F39Y Benign A: 0.010 rs927344 A: 0.008 rs17222603 Exon 3 c.298 C>T p.R100Xf DJS [154] Exon 3 c.299 G>Ae p.R100Q Possibly damaging A: 0.007 [63] Exon 7 c.736 A>C p.M246L Benign C: 0.002 rs8187667 C: 0.002 rs17222744 Exon 7 c.842 G>A p.S281N Benign A: 0.0060.056 [117] Exon 8 c.998 A>G p.D333G Possibly damaging G: 0.002 rs8187668 G: 0.004 rs17222674 Exon 9 c.1058 G>A p.R353H Benign A: 0.009 rs7080681 A: 0.014 rs17216205 Exon 9 c.1177 C>T p.R393W DJS Probably damaging [104, 112] Exon 10 c.1234 A>G p.R412G Probably damaging Deficient methotrexate transport function [56] Exon 10 c.1249 G>A p.V417I Benign None apparent [50] A: 0.163 rs2273697, [146] A: 0.158 rs17216184 A: 0.125 [62] A: 0.1830.312 [117] Exon 10 c.1457 C>T p.T486I Benign T: 0.002 rs8187670 T: 0.002 rs17222589 Exon 11 c.1483 A>G p.K495E Possibly damaging G: 0.002 rs8187672 G: 0.002 rs17222561 Exon 13 c.1686 T>G p.F562L Benign G: 0.002 rs8187673 G: 0.002 rs17216233 Exon 16 c.2009 T>C p.I670T Benign rs8187676 C: 0.006 rs17222632 Exon 16 c.2026 G>C p.G676R DJS Probably damaging [181] Exon 17 c.2125 T>C p.W709R DJS Probably damaging [111] Exon 17 c.2153 A>G p.N718S Possibly damaging rs3740072 Exon 17 c.2215 C>T p.L739F Probably damaging T: 0.006 [51] Exon 18 c.2302 C>T p.R768W DJS Probably damaging Deficient maturation and impaired sorting [47] T: 0.010 [62] [168, 180] Exon 18 c.2366 C>T p.S789F Probably damaging Reduced protein levels [50] T: 0.010 [62] Exon 19 c.2546 T>G p.L849R Benign G: 0.002 rs8187689 G: 0.006 rs17222617 Exon 20 c.2647 G>Ae p.D883N Benign A: 0.007 [63] Exon 20 c.2677 G>C p.E893Q Benign rs3740071 Exon 21 c.2882 A>Ge p.K961R Benign G: 0.007 [63] Exon 22 c.2901 C>A p.Y967Xf A: 0.002 rs8187683 A: 0.002 rs17222547 Exon 22 c.2944 A>G p.I982V Benign G: 0.002 rs8187684 G: 0.002 rs17222554 Exon 22 c.3057 G>Te p.Q1019H Benign T: 0.007 [63] Exon 23 c.3107 T>C p.I1036T Possibly damaging C: 0.002 rs8187685 C: 0.004 rs17216149 Exon 23 c.3188 A>G p.N1063S Benign G: 0.002 rs8187686 G: 0.002 rs17222540 Exon 23 c.3196 C>T p.R1066Xf DJS No ABCC2 protein in liver [134] Exon 25 c.3449 G>A p.R1150H DJS Probably damaging Deficient transport function A: 00.009 [117] Exon 25 c.3517 A>T p.I1173F DJS Probably damaging Deficient maturation and impaired sorting, deficient transport function T: 00.029 [117] [80, 117] Exon 25 c.3521 G>Ae p.R1174H Probably damaging A: 0.007 [63] Exon 25 c.3542 G>T p.R1181L Possibly damaging T: 0.039 rs8187692 T: 0.034 rs17222702 Exon 25 c.3563 T>A p.V1188E Benign A: 0.059 rs8187694 A: 0.059 rs17222723 Exon 26 c.3732 T>Ge p.N1244K Possibly damaging G: 0.014 [63] Exon 27 c.3817 A>G p.T1273A Benign G: 0.002 rs8187699 G: 0.004 rs17222582 Exon 27 c.3825 C>G p.Y1275Xf DJS No ABCC2 protein in liver [104] Exon 28 c.3872 C>T p.P1291L Possibly damaging T: 0.012 rs8187700 T: 0.010 rs17216317 Exon 28 c.3895 A>C p.K1299Q Benign rs4148400, [146] Exon 28 c.3928 C>T p.R1310Xf DJS [166] Exon 29 c.4100 C>Ge p.S1367C Possibly damaging G: 0.007 [63] Exon 29 c.4145 A>G p.Q1382R DJS Probably Deficient [47, 168] Table 3 (continued) Location Nucleotide changea Deduced effect on proteina Causing Dubin-Johnson syndromeb Predicted effect by PolyPhen databasec Experimentally proven functional consequence Average frequency of indicated nucleotide exchange in population NCBI SNP IDd and/or references functionally active ABCC2 protein from the canalicular membrane, their effects on the synthesis and function of the ABCC2 protein differ. Login to comment
140 Although all sequence variants associated with Dubin-Johnson syndrome result in the absence of a Table 3 Nucleotide sequence variants in the human ABCC2 gene (NM_000392) leading to amino acid changes in the ABCC2/MRP2 protein (NP_000383) Location Nucleotide changea Deduced effect on proteina Causing Dubin-Johnson syndromeb Predicted effect by PolyPhen databasec Experimentally proven functional consequence Average frequency of indicated nucleotide exchange in population NCBI SNP IDd and/or references Exon 2 c.56 C>Te p.P19L Probably damaging T: 0.007 [63] Exon 2 c.116 T>A p.F39Y Benign A: 0.010 rs927344 A: 0.008 rs17222603 Exon 3 c.298 C>T p.R100Xf DJS [154] Exon 3 c.299 G>Ae p.R100Q Possibly damaging A: 0.007 [63] Exon 7 c.736 A>C p.M246L Benign C: 0.002 rs8187667 C: 0.002 rs17222744 Exon 7 c.842 G>A p.S281N Benign A: 0.0060.056 [117] Exon 8 c.998 A>G p.D333G Possibly damaging G: 0.002 rs8187668 G: 0.004 rs17222674 Exon 9 c.1058 G>A p.R353H Benign A: 0.009 rs7080681 A: 0.014 rs17216205 Exon 9 c.1177 C>T p.R393W DJS Probably damaging [104, 112] Exon 10 c.1234 A>G p.R412G Probably damaging Deficient methotrexate transport function [56] Exon 10 c.1249 G>A p.V417I Benign None apparent [50] A: 0.163 rs2273697, [146] A: 0.158 rs17216184 A: 0.125 [62] A: 0.1830.312 [117] Exon 10 c.1457 C>T p.T486I Benign T: 0.002 rs8187670 T: 0.002 rs17222589 Exon 11 c.1483 A>G p.K495E Possibly damaging G: 0.002 rs8187672 G: 0.002 rs17222561 Exon 13 c.1686 T>G p.F562L Benign G: 0.002 rs8187673 G: 0.002 rs17216233 Exon 16 c.2009 T>C p.I670T Benign rs8187676 C: 0.006 rs17222632 Exon 16 c.2026 G>C p.G676R DJS Probably damaging [181] Exon 17 c.2125 T>C p.W709R DJS Probably damaging [111] Exon 17 c.2153 A>G p.N718S Possibly damaging rs3740072 Exon 17 c.2215 C>T p.L739F Probably damaging T: 0.006 [51] Exon 18 c.2302 C>T p.R768W DJS Probably damaging Deficient maturation and impaired sorting [47] T: 0.010 [62] [168, 180] Exon 18 c.2366 C>T p.S789F Probably damaging Reduced protein levels [50] T: 0.010 [62] Exon 19 c.2546 T>G p.L849R Benign G: 0.002 rs8187689 G: 0.006 rs17222617 Exon 20 c.2647 G>Ae p.D883N Benign A: 0.007 [63] Exon 20 c.2677 G>C p.E893Q Benign rs3740071 Exon 21 c.2882 A>Ge p.K961R Benign G: 0.007 [63] Exon 22 c.2901 C>A p.Y967Xf A: 0.002 rs8187683 A: 0.002 rs17222547 Exon 22 c.2944 A>G p.I982V Benign G: 0.002 rs8187684 G: 0.002 rs17222554 Exon 22 c.3057 G>Te p.Q1019H Benign T: 0.007 [63] Exon 23 c.3107 T>C p.I1036T Possibly damaging C: 0.002 rs8187685 C: 0.004 rs17216149 Exon 23 c.3188 A>G p.N1063S Benign G: 0.002 rs8187686 G: 0.002 rs17222540 Exon 23 c.3196 C>T p.R1066Xf DJS No ABCC2 protein in liver [134] Exon 25 c.3449 G>A p.R1150H DJS Probably damaging Deficient transport function A: 00.009 [117] Exon 25 c.3517 A>T p.I1173F DJS Probably damaging Deficient maturation and impaired sorting, deficient transport function T: 00.029 [117] [80, 117] Exon 25 c.3521 G>Ae p.R1174H Probably damaging A: 0.007 [63] Exon 25 c.3542 G>T p.R1181L Possibly damaging T: 0.039 rs8187692 T: 0.034 rs17222702 Exon 25 c.3563 T>A p.V1188E Benign A: 0.059 rs8187694 A: 0.059 rs17222723 Exon 26 c.3732 T>Ge p.N1244K Possibly damaging G: 0.014 [63] Exon 27 c.3817 A>G p.T1273A Benign G: 0.002 rs8187699 G: 0.004 rs17222582 Exon 27 c.3825 C>G p.Y1275Xf DJS No ABCC2 protein in liver [104] Exon 28 c.3872 C>T p.P1291L Possibly damaging T: 0.012 rs8187700 T: 0.010 rs17216317 Exon 28 c.3895 A>C p.K1299Q Benign rs4148400, [146] Exon 28 c.3928 C>T p.R1310Xf DJS [166] Exon 29 c.4100 C>Ge p.S1367C Possibly damaging G: 0.007 [63] Exon 29 c.4145 A>G p.Q1382R DJS Probably Deficient [47, 168] Table 3 (continued) Location Nucleotide changea Deduced effect on proteina Causing Dubin-Johnson syndromeb Predicted effect by PolyPhen databasec Experimentally proven functional consequence Average frequency of indicated nucleotide exchange in population NCBI SNP IDd and/or references functionally active ABCC2 protein from the canalicular membrane, their effects on the synthesis and function of the ABCC2 protein differ. Login to comment

[hide] Identification of a novel 974C-->G nonsense mutati... Am J Gastroenterol. 2006 Oct;101(10):2427-32. Epub 2006 Sep 4. Corpechot C, Ping C, Wendum D, Matsuda F, Barbu V, Poupon R
Identification of a novel 974C-->G nonsense mutation of the MRP2/ABCC2 gene in a patient with Dubin-Johnson syndrome and analysis of the effects of rifampicin and ursodeoxycholic acid on serum bilirubin and bile acids.
Am J Gastroenterol. 2006 Oct;101(10):2427-32. Epub 2006 Sep 4., [PMID:16952291]

Abstract [show]
Rifampicin (RIF) and ursodeoxycholic acid (UDCA) therapies have beneficial effects in chronic cholestatic diseases. These may result in part from the induction of multidrug-resistance protein 2 (MRP2/ABCC2) expression in the liver and kidney. However, the precise mechanisms by which RIF and UDCA act in cholestasis remain unclear. In the present study, we report the effects of chronic administration of both drugs in a patient with Dubin-Johnson syndrome (DJS), an inherited autosomal recessive disorder characterized by the absence of functional MRP2 protein at the canalicular hepatocyte membrane. A novel 974C-->G nonsense mutation was identified in the MRP2 gene sequence from this patient. RIF induced further increase in conjugated bilirubinemia, whereas concomitant administration of RIF and UDCA led to a dramatic rise in serum bile acid concentrations. These biochemical effects, which are in marked contrast to those observed in cholestatic settings, were concomitant with an increased MRP3, but not MRP4, expression on basolateral hepatocyte membrane. Such findings highlight the key role of MRP2 in the pharmacological properties of RIF and UDCA and suggest that both drugs should be used with caution in pathologic settings in which MRP2 expression may be downregulated, as in advanced stage of cholestatic diseases.

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78 Mutations in the MRP2/ABCC2 Gene Associated with DJS Nucleotide Mutation Exon Predicted Effect Reference 298C→T 3 R100X 27 974C→G 8 S325X This article IVS8 + 4A→G Intron 8 Aberrant splicing 28 1177C→T 9 R393W 29 1256insCT/ delAAACAG TGAACCT- GATG 10 Frameshift 30 1271A→G 10 R412G 31 1815 + 2T→A 13 Skipped exon 32, 33 1967 + 2T→C 15 Skipped exon 34, 35 2026G→C 16 G676R 35 2125T192;C 17 W709R 36 2302C→T 18 R768W 32, 37, 38 2439 + 2T→C 18 Skipped exon 32, 35, 37 3196C→T 23 R1066X 39, 40 3449G→A 25 R1150H 41 3517A→T 25 I1173F 41 3928C→T 28 R1310X 27, 33 4145A→G 29 Q1382R 37 4175delGGATGA 30 R1392 + M1393 deletion 40 4292delCA 30 Frameshift 30 DISCUSSION Identification of a Novel Nonsense Mutation of the MRP2/ABCC2 Gene Up to now, 18 mutations in the sequence of the MRP2/ABCC2 gene have been reported in DJS, including nonsense mutations, deletions, splicing junction mutations, and missense mutations (Table 1). Login to comment

[hide] Dual hereditary jaundice: simultaneous occurrence ... Gastroenterology. 2005 Jul;129(1):315-20. Cebecauerova D, Jirasek T, Budisova L, Mandys V, Volf V, Novotna Z, Subhanova I, Hrebicek M, Elleder M, Jirsa M
Dual hereditary jaundice: simultaneous occurrence of mutations causing Gilbert's and Dubin-Johnson syndrome.
Gastroenterology. 2005 Jul;129(1):315-20., [PMID:16012956]

Abstract [show]
BACKGROUND & AIMS: Dubin-Johnson syndrome is recessively inherited, conjugated hyperbilirubinemia induced by mutations in the ABCC2/MRP2 gene encoding the canalicular transporter for conjugated bilirubin. Gilbert's syndrome is recessively inherited, unconjugated hyperbilirubinemia caused by decreased conjugation rate of bilirubin associated mostly with homozygous A(TA) 7 TAA variant of the TATAA-box in the UGT1A1 gene promoter. Our aim was to establish the molecular diagnosis in a 3-year-old male with atypical, intermittent, predominantly unconjugated, hyperbilirubinemia. METHODS: 99m Tc-HIDA cholescintigraphy was used for imaging the biliary tree. Expression of ABCC2/MRP2 protein in hepatocytes was investigated immunohistochemically. UGT1A1 and ABCC2/MRP2 genes were sequenced from genomic DNA, and the mutations were verified by fragment analysis, sequencing the cloned exons, and restriction fragment length polymorphism. RESULTS: Cholescintigraphy revealed delayed visualization of the gallbladder. A brown granular lipopigment differing from melanin-like pigment reported in Dubin-Johnson syndrome was present in hepatocytes, but, otherwise, liver histology was normal. ABCC2/MRP2 protein was not detected on the canalicular membrane of hepatocytes, and 2 novel mutations were found in the ABCC2/MRP2 gene: a heterozygous in-frame insertion-deletion mutation 1256insCT/delAAACAGTGAACCTGATG in exon 10 inherited from the father and a heterozygous deletion 4292delCA in exon 30 inherited from the mother. In addition, the patient was homozygous for -3279T>G and A(TA) 7 TAA mutations in the UGT1A1 gene promoter. CONCLUSIONS: Our patient represents a case of digenic mixed hyperbilirubinemia-a distinct type of constitutive jaundice resulting from coinherited defects in ABCC2/MRP2 and UGT1A1 genes.

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56 2125TϾC 17 W709R Machida I et al, Hepatol Res 2004;30:86-90. Login to comment