ABCMdb

ABCB1 p.Gln1107Pro

Predicted by SNAP2:	A: D (53%), C: N (57%), D: N (82%), E: N (87%), F: D (53%), G: N (82%), H: N (97%), I: N (53%), K: N (93%), L: D (71%), M: N (66%), N: N (93%), P: D (71%), R: D (66%), S: N (93%), T: N (93%), V: N (78%), W: D (53%), Y: N (61%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: N, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, R: D, S: D, T: D, V: D, W: D, Y: D,

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[hide] Mechanisms of resistance to anticancer drugs: the ... Pharmacogenomics. 2005 Mar;6(2):115-38. Lepper ER, Nooter K, Verweij J, Acharya MR, Figg WD, Sparreboom A
Mechanisms of resistance to anticancer drugs: the role of the polymorphic ABC transporters ABCB1 and ABCG2.
Pharmacogenomics. 2005 Mar;6(2):115-38., [PMID:15882131]

Abstract [show]
ATP-binding cassette (ABC) genes play a role in the resistance of malignant cells to anticancer agents. The ABC gene products, including ABCB1 (P-glycoprotein) and ABCG2 (breast cancer-resistance protein [BCRP], mitoxantrone-resistance protein [MXR], or ABC transporter in placenta [ABCP]), are also known to influence oral absorption and disposition of a wide variety of drugs. As a result, the expression levels of these proteins in humans have important consequences for an individual's susceptibility to certain drug-induced side effects, interactions, and treatment efficacy. Naturally occurring variants in ABC transporter genes have been identified that might affect the function and expression of the protein. This review focuses on recent advances in the pharmacogenetics of the ABC transporters ABCB1 and ABCG2, and discusses potential implications of genetic variants for the chemotherapeutic treatment of cancer.

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126 In addition to the possible decrease in expression levels, ATPase activity in the ABCG2 +24 Intron 20 G A +40 Intron 20 C T 2547 Exon 21 A G 849 Ile to Met 2650 Exon 21 C T 884 Syn 2677 Exon 21 G T 893 Ala to Ser 2677# Exon 21 G A 893 Ala to Thr +31 Intron 22 G A 2956 Exon 24 A G 986 Met to Val 2995 Exon 24 G A 999 Ala to Thr 3151 Exon 25 C G 1051 Pro to Ala 3320 Exon 26 A C 1107 Gln to Pro 3322 Exon 26 T C 1108 Trp to Arg 3396 Exon 26 C T 1132 Syn 3421 Exon 26 T A 1141 Ser to Thr 3435** Exon 26 C T 1145 Syn 3751 Exon 28 G A 1251 Val to Ile 3767 Exon 28 C A 1256 Thr to Lys 4030 Exon 28 G C Non-coding 4036 Exon 28 A G Non-coding +21 Intron 28 T C Table 2. Summary of common genetic variants in the ABCB1 gene (continued) *cDNA numbers are relative to the ATG site and based on the cDNA sequence from GenBank accession number M14758 with an A as the reference at position 43. Login to comment

[hide] Genetic polymorphisms of ATP-binding cassette tran... Expert Opin Pharmacother. 2005 Nov;6(14):2455-73. Sakurai A, Tamura A, Onishi Y, Ishikawa T
Genetic polymorphisms of ATP-binding cassette transporters ABCB1 and ABCG2: therapeutic implications.
Expert Opin Pharmacother. 2005 Nov;6(14):2455-73., [PMID:16259577]

Abstract [show]
Pharmacogenomics, the study of the influence of genetic factors on drug action, is increasingly important for predicting pharmacokinetics profiles and/or adverse reactions to drugs. Drug transporters, as well as drug metabolism play pivotal roles in determining the pharmacokinetic profiles of drugs and their overall pharmacological effects. There is an increasing number of reports addressing genetic polymorphisms of drug transporters. However, information regarding the functional impact of genetic polymorphisms in drug transporter genes is still limited. Detailed functional analysis in vitro may provide clear insight into the biochemical and therapeutic significance of genetic polymorphisms. This review addresses functional aspects of the genetic polymorphisms of human ATP-binding cassette transporters, ABCB1 and ABCG2, which are critically involved in the pharmacokinetics of drugs.

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106 Position Allele Amino acid Allele frequency in Caucasian populations Allele frequency in Japanese populatins Allele frequency in African populations n % n % n % 61 A G 21 Asn 21 Asp 799 89.7 10.3 193 100 0 100 97.5 2.5 266 T C 89 Met 89 Thr 100 99.5 0.5 145 100 0 100 100 0 307 T C 103 Phe 103 Leu 546 99.9 0.1 48 100 0 ND ND ND 325 G A 108 Glu 108 Lys ND ND ND 37 95.9 4.1 ND ND ND 781 A G 261 Ile 261 Val 100 100 0 145 100 0 100 98.5 1.5 1199 G A 400 Ser 400 Asn 696 95.0 5.0 193 100 0 100 99 1 1985 T G 662 Leu 662 Arg 100 99.5 0.5 145 100 0 100 100 0 2005 C T 669 Arg 669 Cys 100 100 0 145 100 0 100 99 1 2485 A G 829 Ile 829 Val 185 99.2 0.8 ND ND ND ND ND ND 2547 A G 849 Ile 849 Met 100 99.5 0.5 145 100 0 100 100 0 2677 G T A 893 Ala 893 Ser 893 Thr 611 55.1 42.1 2.8 241 40.0 41.1 18.9 100 90 10 0.5 2956 A G 986 Met 986 Val ND ND ND 100 99.5 0.5 ND ND ND 3151 C G 1051 Pro 1051 Ala 100 100 0 145 100 0 100 99.5 0.5 3320 A C 1107 Gln 1107 Pro 461 99.8 0.2 ND ND ND ND ND ND 3322 T C 1108 Trp 1108 Arg 100 100 0 145 100 0 100 99.5 0.5 3421 T A 1141 Ser 1141 Thr 100 100 0 145 100 0 100 88.9 11.1 3751 G A 1251 Val 1251 Ile 100 100 0 145 99 1 100 100 0 3767 C A 1256 Thr 1256 Lys 100 99.5 0.5 145 100 0 100 100 0 Data from [31-38, 203]. Login to comment
129 N21D M89T N44S H2N F103L E108K N183S G185V I261V S400N R492C A599T L662R R669C V801M A893S/T I829V I849M M986V A999T G1063A P1051A Q1107P W1108R I1145M S1141T V1251I T1256K COOH ATP-binding site ATP-binding site EXTRACELLULAR INTRACELLULAR A80E Figure 2. Login to comment

[hide] Role of pharmacogenetics of ATP-binding cassette t... Pharmacol Ther. 2006 Nov;112(2):457-73. Cascorbi I
Role of pharmacogenetics of ATP-binding cassette transporters in the pharmacokinetics of drugs.
Pharmacol Ther. 2006 Nov;112(2):457-73., [PMID:16766035]

Abstract [show]
Interindividual differences of drug response are an important cause of treatment failures and adverse drug reactions. The identification of polymorphisms explaining distinct phenotypes of drug metabolizing enzymes contributed in part to the understanding of individual variations of drug plasma levels. However, bioavailability also depends on a major extent from the expression and activity of drug transport across biomembranes. In particular efflux transporters of the ATP-binding cassette (ABC) family such as ABCB1 (P-glycoprotein, P-gp), the ABCC (multidrug resistance-related protein, MRP) family and ABCG2 (breast cancer resistance protein, BCRP) have been identified as major determinants of chemoresistance in tumor cells. They are expressed in the apical membranes of many barrier tissue such as the intestine, liver, blood-brain barrier, kidney, placenta, testis and in lymphocytes, thus contributing to plasma, liquor, but also intracellular drug disposition. Since expression and function exhibit a broad variability, it was hypothesized that hereditary variances in the genes of membrane transporters could explain at least in part interindividual differences of pharmacokinetics and clinical outcome of a variety of drugs. This review focuses on the functional significance of single nucleotide polymorphisms (SNP) of ABCB1, ABCC1, ABCC2, and ABCG2 in in vitro systems, in vivo tissues and drug disposition, as well as on the clinical outcome of major indications.

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761 0.09d c. 61 A>G N21D 0.11d IVS 5-35 G>C intronic 0.006c IVS 5-25 G>T intronic 0.16c IVS 6+139 C>T intronic 0.37d c. 548 A>G N183S 0.01e c. 1199 G>A S400N 0.05d c. 1236 C>T synonymous 0.41d IVS 12+44 C>T intronic 0.05d c. 1474 C>T R492C 0.01e IVS 17-76 T>A intronic 0.46d IVS 17+137 A>G intronic 0.006c c. 2650 C>T synonymous 0.03e c. 2677 G>T/A A893S/T 0.42d /0.02d c. 2956 A>G M986V 0.005b c. 3320 A>C Q1107P 0.002d c. 3396 C>T synonymous 0.03c c. 3421 T>A S1141T 0.00c c. 3435 C>T synonymous 0.54e c. 4030 G >C synonymous 0.005b c. 4036 A>G synonymous 0.30b a Taniguchi et al. (2003). Login to comment

[hide] Clinical pharmacogenetics and potential applicatio... Curr Drug Metab. 2008 Oct;9(8):738-84. Zhou SF, Di YM, Chan E, Du YM, Chow VD, Xue CC, Lai X, Wang JC, Li CG, Tian M, Duan W
Clinical pharmacogenetics and potential application in personalized medicine.
Curr Drug Metab. 2008 Oct;9(8):738-84., [PMID:18855611]

Abstract [show]
The current 'fixed-dosage strategy' approach to medicine, means there is much inter-individual variation in drug response. Pharmacogenetics is the study of how inter-individual variations in the DNA sequence of specific genes affect drug responses. This article will highlight current pharmacogenetic knowledge on important drug metabolizing enzymes, drug transporters and drug targets to understand interindividual variability in drug clearance and responses in clinical practice and potential use in personalized medicine. Polymorphisms in the cytochrome P450 (CYP) family may have had the most impact on the fate of pharmaceutical drugs. CYP2D6, CYP2C19 and CYP2C9 gene polymorphisms and gene duplications account for the most frequent variations in phase I metabolism of drugs since nearly 80% of drugs in use today are metabolised by these enzymes. Approximately 5% of Europeans and 1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant drug metabolising enzyme that demonstrates genetic variants. Studies into CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and CYP2C9*3 alleles. Extensive polymorphism also occurs in a majority of Phase II drug metabolizing enzymes. One of the most important polymorphisms is thiopurine S-methyl transferases (TPMT) that catalyzes the S-methylation of thiopurine drugs. With respect to drug transport polymorphism, the most extensively studied drug transporter is P-glycoprotein (P-gp/MDR1), but the current data on the clinical impact is limited. Polymorphisms in drug transporters may change drug's distribution, excretion and response. Recent advances in molecular research have revealed many of the genes that encode drug targets demonstrate genetic polymorphism. These variations, in many cases, have altered the targets sensitivity to the specific drug molecule and thus have a profound effect on drug efficacy and toxicity. For example, the beta (2)-adrenoreceptor, which is encoded by the ADRB2 gene, illustrates a clinically significant genetic variation in drug targets. The variable number tandem repeat polymorphisms in serotonin transporter (SERT/SLC6A4) gene are associated with response to antidepressants. The distribution of the common variant alleles of genes that encode drug metabolizing enzymes, drug transporters and drug targets has been found to vary among different populations. The promise of pharmacogenetics lies in its potential to identify the right drug at the right dose for the right individual. Drugs with a narrow therapeutic index are thought to benefit more from pharmacogenetic studies. For example, warfarin serves as a good practical example of how pharmacogenetics can be utilized prior to commencement of therapy in order to achieve maximum efficacy and minimum toxicity. As such, pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and licensed drugs.

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532 Nucleotide change rs number Amino acid change 49T>C rs28381804 F17L 61A>G rs61615398; rs9282564 N21D 131A>G rs1202183 N44S 178A>C rs41315618 I60L 239C>A rs9282565 A80E 266T>C Rs35810889 M89T 431T>C rs61607171 I144T 502G>A rs61122623 V168I 548A>G rs60419673 N183S 554G>T rs1128501 G185V 781A>G rs36008564 I261V 1199G>A rs2229109 S400N 1696G>A rs28381902 E566K 1777C>T rs28381914 R593C 1778G>A rs56107566 R593H 1795G>A rs2235036 A599T 1837G>T rs57001392 D613Y 1985T>G rs61762047 L662R 2005C>T rs35023033 R669C 2207A>T rs41316450 I736K 2398G>A rs41305517 D800N 2401G>A rs2235039 V801M 2485A>G rs2032581 I829V 2506A>G rs28381967 I836V 2547A>G rs36105130 I849M 2677T>A/G rs2032582 S893A/T 2975G>A rs56849127 S992N 3151C>G rs28401798 P1051A 3188G>C rs2707944 G1063A 3262G>A rs57521326 D1088N 3295A>G rs41309225 K1099E 3320A>C rs55852620 Q1107P 3322T>C rs35730308 W1108R 3410G>T rs41309228 S1137I 3421T>A rs2229107 S1141T 3502A>G rs59241388 K1168E 3669A>T rs41309231 E1223D 3751G>A rs28364274 V1251I 3767C>A r35721439 T1256K Data are from NCBI dbSNP (access date: 2 August 2008). Login to comment

[hide] Pharmacogenetics of ATP-binding cassette transport... Methods Mol Biol. 2010;596:95-121. Cascorbi I, Haenisch S
Pharmacogenetics of ATP-binding cassette transporters and clinical implications.
Methods Mol Biol. 2010;596:95-121., [PMID:19949922]

Abstract [show]
Drug resistance is a severe limitation of chemotherapy of various malignancies. In particular efflux transporters of the ATP-binding cassette family such as ABCB1 (P-glycoprotein), the ABCC (multidrug resistance-associated protein) family, and ABCG2 (breast cancer resistance protein) have been identified as major determinants of chemoresistance in tumor cells. Bioavailability depends not only on the activity of drug metabolizing enzymes but also to a major extent on the activity of drug transport across biomembranes. They are expressed in the apical membranes of many barrier tissues such as the intestine, liver, blood-brain barrier, kidney, placenta, testis, and in lymphocytes, thus contributing to plasma, liquor, but also intracellular drug disposition. Since expression and function exhibit a broad variability, it was hypothesized that hereditary variances in the genes of membrane transporters could explain at least in part interindividual differences of pharmacokinetics of a variety of anticancer drugs and many others contributing to the clinical outcome of certain leukemias and further malignancies.

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52 Functional Significance of ABCB1 SNPs Table6.3 Frequency of ABCB1 genetic variants in Caucasians, position on DNA, putative effect, and frequencies (134) Position Amino acid or effect Frequency of the variant allele 5'-Flanking -2903 T>C 0.02a 5'-Flanking -2410 T>C 0.10a 5'-Flanking -2352 G>A 0.28a 5'-Flanking -1910 T>C 0.10a 5'-Flanking -1717 T>C 0.02a 5'-Flanking -1325 A>G 0.02a 5'-Flanking -934 A>G 0.10a 5'-Flanking -692 T>C 0.10a 5'-Flanking -41 A>G 0.09b IVS 1a -145 C>G 0.02b IVS 1b -129 T>C 0.06b IVS 1b 12 T>C 0.06c IVS 2 -1 G>A 0.09d c. 61 A>G N21D 0.11d IVS 5 -35 G>C Intronic 0.006c IVS 5 -25 G>T Intronic 0.16c IVS 6 +139 C>T Intronic 0.37d c. 548 A>G N183S 0.01e c. 1199 G>A S400N 0.05d c. 1236 C>T Synonymous 0.41d IVS 12 +44 C>T Intronic 0.05d c. 1474 C>T R492C 0.01e IVS 17 -76 T>A Intronic 0.46d IVS 17 +137 A>G Intronic 0.006c c. 2650 C>T Synonymous 0.03e c. 2677 G>T/A A893S/T 0.42d /0.02d c. 2956 A>G M986V 0.005b c. 3320 A>C Q1107P 0.002d c. 3396 C>T Synonymous 0.03c c. 3421 T>A S1141T 0.00c c. 3435 C>T Synonymous 0.54d c. 4030 Synonymous 0.005b c. 4036 Synonymous 0.30b References: a [42], b [26], c [25], d [28], e [23] with lower activity or expression in Caucasians. Login to comment

[hide] Influence of ABCB1, ABCC1, ABCC2, and ABCG2 haplot... Pharmacogenet Genomics. 2005 Sep;15(9):599-608. Colombo S, Soranzo N, Rotger M, Sprenger R, Bleiber G, Furrer H, Buclin T, Goldstein D, Decosterd L, Telenti A
Influence of ABCB1, ABCC1, ABCC2, and ABCG2 haplotypes on the cellular exposure of nelfinavir in vivo.
Pharmacogenet Genomics. 2005 Sep;15(9):599-608., [PMID:16041239]

Abstract [show]
OBJECTIVES: The human immunodeficiency virus protease inhibitor nelfinavir is substrate of polyspecific drug transporters encoded by ABCB1 (P-glycoprotein), ABCC1 (MRP1) and ABCC2 (MRP2), and an inhibitor of BCRP, encoded by ABCG2. Genetic polymorphism in these genes may be associated with changes in transport function. METHODS: A comprehensive evaluation of single nucleotide polymorphisms (39 SNPs in ABCB1, 7 in ABCC1, 27 in ABCC2, and 16 in ABCG2), and inferred haplotypes was done to assess possible associations of genetic variants with cellular exposure of nelfinavir in vivo. Analysis used peripheral mononuclear cells from individuals receiving nelfinavir (n=28). Key results were re-examined in a larger sample size (n=129) contributing data on plasma drug levels. RESULTS AND CONCLUSIONS: There was no significant association between cellular nelfinavir area under the curve (AUC) and SNPs or haplotypes at ABCC1, ABCC2, ABCG2. There was an association with cellular exposure for two loci in strong linkage disequilibrium: ABCB1 3435C>T; AUCTT>AUCCT>AUCCC (ratio 2.1, 1.4, 1, Ptrend=0.01), and intron 26 +80T>C; AUCCC> AUCCT > AUCTT (ratio 2.4, 1.3, 1, Ptrend=0.006). Haplotypic analysis using tagging SNPs did not improve the single SNP association values.

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70 2650C > T exon 21 synonymous (p.L884L) Kim et al., 2001 md-v-110 rs9282563 c.2677G > T exon 21 p.A893S Kim et al., 2001 md-v-031 rs2032582 c.2677G > A exon 21 p.A893T Kim et al., 2001 md-v-109 IVS 21 + 14 - 17 delAATA intron 21 Epidauros md-v-092 IVS 21 + 49 T > C intron 21 Epidauros md-v-042 rs2032583 IVS 21 + 66 T > C intron 21 Epidauros md-v-108 IVS 26 - 156 T > C intron 25 Epidauros md-v-095 IVS 26 - 68 A > G intron 25 Epidauros md-v-164 c.3320A > C exon 26 p.Q1107P Cascorbi et al., 2002 md-v-033 c.3322T > C exon 26 p.W1108R Kroetz et al., 2003 md-v-225 c.3325C > T exon 26 p.L1109F Epidauros md-v-165 c 3364C > T exon 26 synonymous (p.A1132A) Hoffmeyer et al., 2000 md-v-034 c.3321T > A exon 26 p.S1141T Kim et al., 2001 md-v-035 c.3435C > T (Tag8) exon 26 synonymous (p.I1145I) Hoffmeyer et al., 2000 md-v-036 rs1045642 IVS 26 + 59 T > G intron 26 Epidauros md-v-097 rs2235047 IVS 26 + 80 T > C intron 26 Epidauros md-v-040 rs2235048 IVS 26 + 123_24 insCATG intron 26 Epidauros md-v-096 Tag 11 intron 27 Soranzo et al., 2004 rs1186746 Tag 12 intron 27 Soranzo et al., 2004 rs1186745 MRP1 (ABCC1) c.816G > A exon 8 synonymous (p.P272P) Epidauros mr-v-014 c.825T > C exon 8 synonymous (p.V275V) Saito et al., 2002 mr-v-015 rs246221 c.1062T > C exon 9 synonymous (p.N354N) Saito et al., 2002 mr-v-016 rs35587 c.1068G > A exon 9 synonymous (p.T356T) Epidauros mr-v-057 rs8187852 IVS 9 + 8 A > G intron 9 Saito et al., 2002 mr-v-017 rs35588 c.1303G > T exon 10 p.R433S Conrad et al., 2002 mr-v-018 IVS 10 + 64 C > T intron 10 Epidauros mr-v-019 MRP2 (ABCC2) g. Login to comment

[hide] Frequency of single nucleotide polymorphisms in th... Clin Pharmacol Ther. 2001 Mar;69(3):169-74. Cascorbi I, Gerloff T, Johne A, Meisel C, Hoffmeyer S, Schwab M, Schaeffeler E, Eichelbaum M, Brinkmann U, Roots I
Frequency of single nucleotide polymorphisms in the P-glycoprotein drug transporter MDR1 gene in white subjects.
Clin Pharmacol Ther. 2001 Mar;69(3):169-74., [PMID:11240981]

Abstract [show]
BACKGROUND: P-glycoprotein, the gene product of MDR1, confers multidrug resistance against antineoplastic agents but also plays an important role in the bioavailability of common drugs in medical treatment. Various polymorphisms in the MDR1 gene were recently identified. A silent mutation in exon 26 (C3435T) was correlated with intestinal P-glycoprotein expression and oral bioavailability of digoxin. OBJECTIVE: We wanted to establish easy-to-use and cost-effective genotyping assays for the major known MDR1 single nucleotide polymorphisms and study the allelic frequency distribution of the single nucleotide polymorphisms in a large sample of volunteers. METHODS: In this study, the distribution of the major MDR1 alleles was determined in 461 white volunteers with the use of polymerase chain reaction and restriction fragment length polymorphism. RESULTS: Five amino acid exchanges were found with allelic frequencies of 11.2% for Asn21Asp and 5.5% for Ser400Asn. Strikingly, in exon 21 three variants were discovered at the same locus: 2677G (56.4%), 2677T (41.6%), and 2677A (1.9%), coding for 893Ala, Ser, or Thr. A novel missense Gln1107Pro mutation was found in two cases (0.2%). The highest frequencies were observed for intronic and silent polymorphisms; C3435T occurred in 53.9% of the subjects heterozygously, and 28.6% of individuals were homozygous carriers of 3435T/T with functionally restrained P-glycoprotein. CONCLUSION: This study provides the first analysis of MDR1 variant genotype distribution in a large sample of white subjects. It gives a basis for large-scale clinical investigations on the functional role of MDR1 allelic variants for bioavailability of a substantial number of drugs.

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7 A novel missense Gln1107Pro mutation was found in two cases (0.2%). Login to comment
58 In addition, a novel amino acid exchange, Gln1107Pro exchange in exon 26 (A3320C), was identified heterozygously in 2 subjects with the use of denaturing HPLC. Login to comment
81 An additional amino acid exchange was identified in exon 26; this led to a Gln1107Pro replacement heterozygously in 2 subjects. Login to comment
96 Two further amino acid exchanges, Ala893Thr and Gln1107Pro, were identified. Login to comment

[hide] Does the A118G polymorphism at the mu-opioid recep... Anesthesiology. 2002 Oct;97(4):814-9. Lotsch J, Zimmermann M, Darimont J, Marx C, Dudziak R, Skarke C, Geisslinger G
Does the A118G polymorphism at the mu-opioid receptor gene protect against morphine-6-glucuronide toxicity?
Anesthesiology. 2002 Oct;97(4):814-9., [PMID:12357145]

Abstract [show]
BACKGROUND: Some, but not all, patients with renal dysfunction suffer from side effects after morphine administration because of accumulation of the active metabolite morphine-6-glucuronide (M6G). The current study aims to identify genetic causes that put patients at risk for, or protect them from, opioid side effects related to high plasma M6G. Candidate genetic causes are the single nucleotide polymorphism (SNP) A118G of the mu-opioid-receptor gene (OPRM1), which has recently been identified to result in decreased potency of M6G, and mutations in the MDR1-gene coding P-glycoprotein, of which morphine and M6G might be a substrate. METHODS: Two men, aged 87 and 65 yr, with renal failure (creatinine clearance of 6 and 9 ml/min) received 30 mg/day oral morphine for pain treatment. Both patients had sufficient analgesia from morphine. However, while one patient tolerated morphine well despite high plasma M6G of 1735 nM, in the patient with M6G plasma concentrations of 941 nM it caused severe sleepiness and drowsiness. Patients were genotyped for known SNPs of the OPRM1 and MDR1 genes. RESULTS: The patient who tolerated morphine well despite high plasma M6G was a homozygous carrier of the mutated G118 allele of the mu-opioid-receptor gene, which has been previously related to decreased M6G potency. In contrast, the patient who suffered from side effects was "wild-type" for this mutation. No other differences were found between the OPRM1 and MDR1 genes. CONCLUSIONS: The authors hypothesize that the A118G single nucleotide polymorphism of the mu-opioid-receptor is among the protective factors against M6G-related opioid toxicity. The observation encourages the search for pharmacogenetic reasons that cause interindividual variability of the clinical effects of morphine.

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106 33 T/T T/T MDR1 2 A61G Asn21Asp 11.2 20.6 9 A/G A/G Forward: 5Ј-AGG AGC AAA GAA GAA GAA CTT TTT TAA ACT GAT C-3Ј 9.3 17.6 8 Reverse: 5Ј-GAT TCC AAA GGC TAG CTT GC-3Ј 5 T307C Phe103Leu 0.6 1.2 9 T/T T/T Forward: 5Ј-GTG GTT GCA CAC AGT CAG CA-3Ј Reverse: 5Ј-GGA GGA TGT CTA ATT ACC TGG TCA-3Ј 11 G1199A Ser400Asn 5.5 11.1 9 G/G G/G Forward: 5Ј-CAG CTA TTC GAA GAG TGG GC-3Ј 6.5 12.9 8 Reverse: 5Ј-CCG TGA GAA AAA AAC TTC AAG G-3Ј 21 G2677T Ala893Ser 41.6 49.2 9 T/T T/T Forward: 5Ј-TGC AGG CTA TAG GTT CCA GG-3Ј 63.9 43.4 8 Reverse: 5Ј-GTT TGA CTC ACC TTC CCA G-3Ј 21 G2677A Ala893Thr 0.9 2 9 NA NA Forward: 5Ј-TGC AGG CTA TAG GTT CCA GG-3Ј Reverse: 5Ј-TTT AGT TTG ACT CAC CTT CCC G-3Ј 26 A3320C Gln1107Pro 0.2 0.4 9 A/A A/A 26 C3396T Ala1132Ala 0.3 0.5 8 C/C C/C Forward: 5Ј-ATC TGT GAA CTC TTG TTT TCA GC-3Ј 26 C3435T Ile1145Ile 50.3 47.7 8 T/T T/T Reverse: 5Ј-TCG ATG AAG GCA TGT ATG TTG-3Ј 53.9 50.5 9 - - MRP2 10 G1249A Val417Ile 12.5 20.8 34 G/G G/G Forward: 5Ј-GGG TCC TAA TTT CAA TCC TTA-3Ј Reverse: 5Ј-TAT TCT TCT GGG TGA CTT TTT-3Ј 18 C2302T Arg768Trp 1 2.1 34 C/C C/C Forward: 5Ј-GGA GTA GTG CTT AAT ATG AAT-3Ј 18 C2366T Ser789Phe 1 2.1 34 C/C C/C Reverse: 5Ј-CCC ACC CCA CCT TTA TAT CTT-3Ј 28 C3972T Ile132Ile 21.9 35.4 34 C/T C/T Forward: 5Ј-TGC TAC CCT TCT CCT GTT CTA-3Ј Reverse: 5Ј-ATC CAG GCC TTC CTT CAC TCC-3Ј 31 G4348A Ala1450Thr 1 2.1 34 G/G G/G Forward: 5Ј-AGG AGC TAA CAC ATG GTT GCT-3Ј Reverse: 5Ј-GGG TTA AGC CAT CCG TGT CAA-3Ј † Sequence is not translated. Login to comment

[hide] Genetic polymorphisms of the human MDR1 drug trans... Annu Rev Pharmacol Toxicol. 2003;43:285-307. Epub 2002 Jan 10. Schwab M, Eichelbaum M, Fromm MF
Genetic polymorphisms of the human MDR1 drug transporter.
Annu Rev Pharmacol Toxicol. 2003;43:285-307. Epub 2002 Jan 10., [PMID:12359865]

Abstract [show]
P-glycoprotein is an ATP-dependent efflux pump that contributes to the protection of the body from environmental toxins. It transports a huge variety of structurally diverse compounds. P-glycoprotein is involved in limiting absorption of xenobiotics from the gut lumen, in protection of sensitive tissues (brain, fetus, testis), and in biliary and urinary excretion of its substrates. P-glycoprotein can be inhibited or induced by xenobiotics, thereby contributing to variable drug disposition and drug interactions. Recently, several SNPs have been identified in the MDR1 gene, some of which can affect P-glycoprotein expression and function. Potential implications of MDR1 polymorphisms for drug disposition, drug effects, and disease risk are discussed.

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60 In a Northern Italian population, the extent of linkage disequilibrium TABLE 2 Summary of MDR1 genetic variants in different ethnic groups Location Position Allele Effect Reference promotor 5 flanking/-41a A (28) G exon 1a exon 1a/-145 C (28) G exon 1b exon 1b/-129 T (25, 33) C intron 1 exon 2/-4 C (29) T intron 1 exon 2/-1 G initiation of translation (25, 27, 29) A exon 2 exon 2/61 A Asn21Asp (25-27, 29) G intron 4 exon 5/-35 G (25) C intron 4 exon 5/-25 G (25) T exon 5 exon 5/307 T Phe103Leu (25) C intron 6 exon 6/+139 C (25, 27) T intron 6 exon 6/+145 C (25) T exon 7 exon 7/548 A Asn183Ser (29) G exon 11 exon 11/1199 G Ser400Asn (25, 27, 29) A exon 12 exon 12/1236 C wobble (23, 25, 27, 29) T (Gly412Gly) intron 12 exon 12/+44 C (25, 27) T exon 13 exon 13/1474 C Arg492Cys (29) T intron 16 exon 17/-76 T (25, 27) A intron 17 exon 17/137 A (25) G exon 21 exon 21/2650 C wobble (29) T (Leu884Leu) (Continued ) TABLE 2 (Continued) Location Position Allele Effect Reference exon 21 exon 21/2677 G (22, 23, 27, 29) T Ala893Ser A Ala893Thr exon 24 exon 24/2956 A Met986Val (33) G exon 24 exon 24/2995 G Ala999Thr (22) A exon 26 exon 26/3320 A Gln1107Pro (27) C exon 26 exon 26/3396 C wobble (25) T exon 26 exon 26/3421 T Ser1141Thr (29, 30) A exon 26 exon 26/3435 C wobble (23, 25, 29) T (Ile1145Ile) exon 28 exon 28/4030 G (33) C exon 28 exon 28/4036 A (23, 33) G The positions of the polymorphisms correspond to positions of MDR1 cDNA with the first base of the ATG start codon set to 1 (GenBank accession # M14758). Login to comment

[hide] MDR1 genotype-related pharmacokinetics and pharmac... Biol Pharm Bull. 2002 Nov;25(11):1391-400. Sakaeda T, Nakamura T, Okumura K
MDR1 genotype-related pharmacokinetics and pharmacodynamics.
Biol Pharm Bull. 2002 Nov;25(11):1391-400., [PMID:12419946]

Abstract [show]
The multidrug resistant transporter MDR1/P-glycoprotein, the gene product of MDR1, is a glycosylated membrane protein of 170 kDa, belonging to the ATP-binding cassette superfamily of membrane transporters. MDR1 acts as an energy-dependent efflux pump that exports its substrates out of cells. MDR1 was originally isolated from resistant tumor cells as part of the mechanism of multidrug resistance, but over the last decade, it has been elucidated that human MDR1 is also expressed throughout the body to confer intrinsic resistance to the tissues by exporting unnecessary or toxic exogeneous substances or metabolites. A number of structurally unrelated drugs are substrates for MDR1, and MDR1 and other transporters are recognized as an important class of proteins for regulating pharmacokinetics and pharmacodynamics. In 2000, Hoffmeyer et al. performed a systemic screening for MDR1 polymorphisms and detected 15 single nucleotide polymorphisms (SNPs). They also indicated that a polymorphism in exon 26 at position 3435 (C3435T), a silent mutation, affected the expression level of MDR1 protein in duodenum, and thereby the intestinal absorption of digoxin. To date, the genotype frequencies of C3435T have been investigated extensively using a larger population and interethnic difference has been elucidated, and a total of 28 SNPs have been found at 27 positions on the MDR1 gene. Clinical studies on MDR1 genotype-related MDR1 expression and pharmacokinetics have also been performed around the world; however, results were not always consistent with Hoffmeyer's report. In this review, published reports are summarized for the future individualization of pharmacotherapy based on MDR1 genotyping. In addition, recent investigations have raised the possibility that MDR1 and related transporters play a fundamental role in regulating apoptosis and immunology, and in fact, there are reports of MDR1-related susceptibility to inflammatory bowel disease, HIV infection and renal cell carcinoma. Herein, these issues are also summarized, and the current status of the knowledge in the area of pharmacogenomics of other transporters is briefly introduced.

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56 In 2001, Hitzl et al. also indicated that healthy Caucasian subjects with T/T3435 had a more decreased efflux of rhodamine from CD56ϩ NK cells and a lower MDR1 mRNA expression in leukocytes than those with C/C3435 .65) In renal tissues, the C3435T polymorphism is reported to be associated with reduced MDR1 expression.31) However, Tanabe et al. suggested that C3435T had no effect on the placental MDR1 expression based on 89 subjects and Western blotting.53) We determined MDR1 mRNA levels in biopsy specimens of the duodenum obtained from 13 healthy Japanese subjects by real time quantitative RT-PCR and found that MDR1 mRNA expression was higher in T/T3435 than C/C3435 or C/T3435 (Fig. 1).66) The discrepancies between the reports might be ex- November 2002 1393 Table 2. Summary of Genetic Polymorphisms in MDR1 Position Location Effect A1a/-41G Intron Noncoding C-145G Exon 1a Noncoding T-129C (T12C) Exon 1b Noncoding C-4T Exon 2 Noncoding G-1A Exon 2 Noncoding A61G Exon 2 Asn21Asp G5/-25T Intron G5/-35C Intron T307C Exon 5 Phe103Leu C6/ϩ139T Intron A548G Exon 7 Asn183Ser G1199A Exon 11 Ser400Asn C1236T Exon 12 Silent C12/ϩ44T Intron C1474T Exon 13 Arg492Cys T17/-76A Intron A17/ϩ137G Intron C2650T Exon 21 Silent G2677(A,T) Exon 21 Ala893Thr (G2677A) Ala893Ser (G2677T) A2956G Exon 24 Met986Val G2995A Exon 24 Ala999Thr A3320C Exon 26 Gln1107Pro C3396T Exon 26 Silent T3421A Exon 26 Ser1141Thr C3435T Exon 26 Silent G4030C Exon 28 Silent A4036G Exon 28 Silent This list was based on the literature (refs. 49-54). Login to comment

[hide] Pharmacogenetics of MDR1 and its impact on the pha... Pharmacogenomics. 2003 Jul;4(4):397-410. Sakaeda T, Nakamura T, Okumura K
Pharmacogenetics of MDR1 and its impact on the pharmacokinetics and pharmacodynamics of drugs.
Pharmacogenomics. 2003 Jul;4(4):397-410., [PMID:12831320]

Abstract [show]
The multi-drug resistant transporter MDR1/P-glycoprotein, the gene product of MDR1, is a glycosylated membrane protein of 170 kDa, belonging to the ATP-binding cassette (ABC) superfamily of membrane transporters. MDR1 was originally isolated from resistant tumor cells as part of the mechanism of multi-drug resistance, but over the last decade, it has been elucidated that human MDR1 is also expressed throughout the body to confer intrinsic resistance to the tissues by exporting unnecessary or toxic exogeneous substances or metabolites. A number of various types of structurally unrelated drugs are substrates for MDR1, and MDR1 and other transporters are recognized as an important class of proteins for regulating pharmacokinetics and pharmacodynamics. In 2000, Hoffmeyer et al. performed a systemic screening for MDR1 polymorphisms and indicated that a single nucleotide polymorphism (SNP), C3435T in exon 26, which caused no amino acid change, was associated with the duodenal expression of MDR1 and thereby the plasma concentrations of digoxin after oral administration. Interethnic differences in genotype frequencies of C3435T have been clarified, and, at present, a total of 28 SNPs have been found at 27 positions on the MDR1 gene. Clinical studies on the effects of C3435T on MDR1 expression and function in the tissues, and also on the pharmacokinetics and pharmacodynamics have been performed around the world; however, there are still discrepancies in the results, suggesting that the haplotype analysis of the gene should be included instead of SNP detection, and the design of clinical trials must be carefully planned to avoid misinterpretations. A polymorphism of C3435T is also reported to be a risk factor for a certain class of diseases such as the inflammatory bowel diseases, Parkinson's disease and renal epithelial tumor, and this might also be explained by the effects on MDR1 expression and function. In this review, the latest reports are summarized for the future individualization of pharmacotherapy based on MDR1 genotyping.

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75 Position Location Effect A1a/-41G Intron Non-coding C-145G Exon 1a Non-coding T-129C (T12C) Exon 1b Non-coding C-4T Exon 2 Non-coding G-1A Exon 2 Non-coding A61G Exon 2 Asn21Asp G5/-25T Intron G5/-35C Intron T307C Exon 5 Phe103Leu C6/+139T Intron A548G Exon 7 Asn183Ser G1199A Exon 11 Ser400Asn C1236T Exon 12 Silent C12/+44T Intron C1474T Exon 13 Arg492Cys T17/-76A Intron A17/+137G Intron C2650T Exon 21 Silent G2677(A,T) Exon 21 Ala893Thr (G2677A) Ala893Ser (G2677T) A2956G Exon 24 Met986Val G2995A Exon 24 Ala999Thr A3320C Exon 26 Gln1107Pro C3396T Exon 26 Silent T3421A Exon 26 Ser1141Thr C3435T Exon 26 Silent G4030C Exon 28 Silent A4036G Exon 28 Silent See references [34-39]. Login to comment

[hide] P-glycoprotein: from genomics to mechanism. Oncogene. 2003 Oct 20;22(47):7468-85. Ambudkar SV, Kimchi-Sarfaty C, Sauna ZE, Gottesman MM
P-glycoprotein: from genomics to mechanism.
Oncogene. 2003 Oct 20;22(47):7468-85., 2003-10-20 [PMID:14576852]

Abstract [show]
Resistance to chemically different natural product anti-cancer drugs (multidrug resistance, or MDR) results from decreased drug accumulation, resulting from expression of one or more ATP-dependent efflux pumps. The first of these to be identified was P-glycoprotein (P-gp), the product of the human MDR1 gene, localized to chromosome 7q21. P-gp is a member of the large ATP-binding cassette (ABC) family of proteins. Although its crystallographic 3-D structure is yet to be determined, sequence analysis and comparison to other ABC family members suggest a structure consisting of two transmembrane (TM) domains, each with six TM segments, and two nucleotide-binding domains. In the epithelial cells of the gastrointestinal tract, liver, and kidney, and capillaries of the brain, testes, and ovaries, P-gp acts as a barrier to the uptake of xenobiotics, and promotes their excretion in the bile and urine. Polymorphisms in the MDR1 gene may affect the pharmacokinetics of many commonly used drugs, including anticancer drugs. Substrate recognition of many different drugs occurs within the TM domains in multiple-overlapping binding sites. We have proposed a model for how ATP energizes transfer of substrates from these binding sites on P-gp to the outside of the cell, which accounts for the apparent stoichiometry of two ATPs hydrolysed per molecule of drug transported. Understanding of the biology, genetics, and biochemistry of P-gp promises to improve the treatment of cancer and explain the pharmacokinetics of many commonly used drugs.

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85 Kioka et al. (1989) showed a slight increase in resistance to doxorubicin, but no effect on colchicine or vinblastine Table 2 Common MDR1 exonic polymorphisms Exon number Polymorphic nucleotide variant Change in amino acid References 1 À145 - Ito et al. (2001) 1 À129 - Hoffmeyer et al. (2000); Tanabe et al. (2001) 2 61 N21D Cascorbi et al. (2001); Decleves et al. (2000); Hoffmeyer et al. (2000); Kim et al. (2001) 5 307 F103L Hoffmeyer et al. (2000) 7 548 N183S Kim et al. (2001) 10 1107 G369P Hoffmeyer et al. (2000) 11 1199 S400N Cascorbi et al. (2001); Hoffmeyer et al. (2000); Kim et al. (2001) 12 1236 Wobble Cascorbi et al. (2001); Hoffmeyer et al. (2000); Kim et al. (2001); Kioka et al. (1989) 13 1474 R492C Kim et al. (2001) 21 2650 Wobble Kim et al. (2001) 21 2677 893A, S, or T Cascorbi et al. (2001); Kim et al. (2001); Kioka et al. (1989); Mickley et al. (1998) 24 2956 M986V Tanabe et al. (2001) 24 2995 A999T Mickley et al. (1998) 26 3320 Q1107P Cascorbi et al. (2001) 26 3396 Wobble Hoffmeyer et al. (2000) 26 3421 S1141T Kim et al. (2001) 26a 3435 Wobble Hoffmeyer et al. (2000); Kim et al. (2001); Kioka et al. (1989) 28 4030 - Tanabe et al. (2001) 28 4036 - Kioka et al. (1989); Tanabe et al. (2001) a The only polymorphism that correlates with changes in drug delivery and disposition P-glycoprotein SV Ambudkar et al resistance in the SNP located on exon 21, position 2677, Ser893 (Kioka et al., 1989). Login to comment

[hide] Polymorphisms in human MDR1 (P-glycoprotein): rece... Clin Pharmacol Ther. 2004 Jan;75(1):13-33. Marzolini C, Paus E, Buclin T, Kim RB
Polymorphisms in human MDR1 (P-glycoprotein): recent advances and clinical relevance.
Clin Pharmacol Ther. 2004 Jan;75(1):13-33., [PMID:14749689]

Abstract [show]
Drug transporters are increasingly recognized to be important to drug disposition and response. P-glycoprotein, the encoded product of the human MDR1 (ABCB1) gene, is of particular clinical relevance in that this transporter has broad substrate specificity, including a variety of structurally divergent drugs in clinical use today. Moreover, expression of this efflux transporter in certain tissue compartments such as the gastrointestinal tract and brain capillary endothelial cells limits oral absorption and central nervous system entry of many drugs. Recently, a number of single-nucleotide polymorphisms (SNPs) in MDR1 have been identified. An increasing number of studies have also implicated certain commonly occurring SNPs in MDR1 in problems including altered drug levels and host susceptibility to diseases such as Parkinson's disease, inflammatory bowel disease, refractory seizures, and CD4 cell recovery during human immunodeficiency virus therapy. However, in many such cases, the reported effects of MDR1 SNPs have been inconsistent and, in some cases, conflicting. In this review SNPs in MDR1 in relation to population frequencies, drug levels, and phenotypes are outlined. In addition, issues relating to MDR1 haplotypes, environmental factors, and study design, as potential confounding factors of the observed MDR1 polymorphism effect in vivo, are also discussed.

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75 Summary of genetic polymorphisms in MDR1 Location Position Mutation Effect Mutant allele frequency (%) Hoffmeyer et al89 : C Cascorbi et al90 : C Siegmund et al91 : C Promotor 5' flanking/-41 A/G Noncoding Exon 1a Exon 1a/-145 C/G Noncoding Exon 1b Exon 1b/-129 T/C Noncoding 5.9 Intron 1 Exon 2/-4 C/T Noncoding Intron 1 Exon 2/-1 G/A Initial translation 5.6 9 3.7 Exon 2 Exon 2/61 A/G Asn21Asp 9.3 11.2 8.9 Intron 4 Exon 5/-35 G/C 0.6 Intron 4 Exon 5/-25 G/T 16.5 Exon 5 Exon 5/307 T/C Phe103Leu 0.6 0 Intron 6 Exon 6/ϩ139 C/T 40.6 37.2 35.8 Intron 6 Exon 6/ϩ145 C/T 1.2 Exon 7 Exon 7/548 A/G Asn183Ser Exon 11 Exon 11/1199 G/A Ser400Asn 6.5 5.5 2.9 Exon 12 Exon 12/1236 C/T Silent 37.8 41 34.3 Intron 12 Exon 12/ϩ44 C/T 5.9 4.9 7.5 Exon 13 Exon 13/1474 C/T Arg492Cys Intron 16 Exon 17/-76 T/A 45.3 46.2 49.3 Intron 17 Exon 17/ϩ137 A/G 0.6 Exon 21 Exon 21/2650 C/T Silent Exon 21 Exon 21/2677 G/T Ala893Ser 41.6 40.3 G/A Ala893Thr 1.9 3.7 Exon 24 Exon 24/2956 A/G Met986Val Exon 24 Exon 24/2995 G/A Ala999Thr Exon 26 Exon 26/3320 A/C Gln1107Pro 0.2 Exon 26 Exon 26/3396 C/T Silent 0.3 Exon 26 Exon 26/3421 T/A Ser1141Thr Exon 26 Exon 26/3435 C/T Silent 48.1 53.9 50.7 Exon 28 Exon 28/4030 G/C Exon 28 Exon 28/4036 A/G The positions of the polymorphisms were established with the first base of the ATG start codon set to 1. Login to comment

[hide] Pharmacogenetics of drug transporters and its impa... Curr Top Med Chem. 2004;4(13):1385-98. Sakaeda T, Nakamura T, Okumura K
Pharmacogenetics of drug transporters and its impact on the pharmacotherapy.
Curr Top Med Chem. 2004;4(13):1385-98., [PMID:15379652]

Abstract [show]
Most drug responses are determined by the interplay of several gene products that influence pharmacokinetics and pharmacodynamics, i.e., drug metabolizing enzymes, drug transporters, and drug targets. With the sequencing of the human genome, it has been estimated that approximately 500-1200 genes code for drug transporters. Concerning the effects of genetic polymorphisms on pharmacotherapy, the best characterized drug transporter is the multidrug resistant transporter P-glycoprotein/MDR1, the gene product of MDR1. Little such information is available on other drug transporters. MDR1 is a glycosylated membrane protein of 170 kDa, belonging to the ATP-binding cassette superfamily, and is expressed mainly in intestines, liver, kidneys and brain. A number of various types of structurally unrelated drugs are substrates for MDR1, and their intestinal absorption, hepatobiliary secretion, renal secretion and brain transport are regulated by MDR1. The first investigation on the effects of MDR1 genotypes on pharmacotherapy was reported in 2000: a silent single nucleotide polymorphism (SNP), C3435T in exon 26, was found to be associated with the duodenal expression of MDR1, and thereby the plasma concentration of digoxin after oral administration. At present, a total of 28 SNPs have been found at 27 positions on the MDR1 gene. Clinical investigations on the association of MDR1 genotypes with the expression and function of MDR1 in tissues, and with pharmacokinetics and pharmacodynamics have mainly focused on C3435T; however, there are still discrepancies in the results, suggesting that the haplotype of the gene should be analyzed instead of a SNP. C3435T is also reported to be a risk factor for a certain class of diseases including the inflammatory bowel diseases, Parkinson's disease and renal epithelial tumor, and this also might be explained by the effects on MDR1 expression and function. In this review, the latest reports on the effects of genetic polymorphisms of MDR1 on pharmacotherapy are summarized, and the pharmacogenetics of other transporters is briefly introduced.

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127 Position Location Effect A1a/-41G intron noncoding C-145G exon 1a noncoding T-129C (T12C) exon 1b noncoding C-4T exon 2 noncoding G-1A exon 2 noncoding A61G G5/-25T G5/-35C exon 2 intron intron Asn21Asp T307C C6/+139T exon 5 intron Phe103Leu A548G exon 7 Asn183Ser G1199A exon 11 Ser400Asn C1236T C12/+44T exon 12 intron silent C1474T T17/-76A A17/+137G exon 13 intron intron Arg492Cys C2650T exon 21 silent G2677(A,T) exon 21 Ala893Thr (G2677A) Ala893Ser (G2677T) A2956G exon 24 Met986Val G2995A exon 24 Ala999Thr A3320C exon 26 Gln1107Pro C3396T exon 26 silent T3421A exon 26 Ser1141Thr C3435T exon 26 silent G4030C exon 28 silent A4036G exon 28 silent The list was based on the reports [67,68,71-74]. Login to comment

[hide] Polymorphisms in multidrug resistance 1 (MDR1) gen... Genes Immun. 2004 Nov;5(7):530-9. Potocnik U, Ferkolj I, Glavac D, Dean M
Polymorphisms in multidrug resistance 1 (MDR1) gene are associated with refractory Crohn disease and ulcerative colitis.
Genes Immun. 2004 Nov;5(7):530-9., [PMID:15505619]

Abstract [show]
We used coding and noncoding polymorphisms evenly spaced across the ABCB1/MDR1 gene to perform association analysis in Slovenian patients with inflammatory bowel diseases and to obtain haplotype structure and patterns of linkage disequilibrium (LD) in the MDR1 gene. A disease association study was performed in 307 IBD patients, including 144 patients with ulcerative colitis (UC) and 163 patients with Crohn's disease (CD), and 355 healthy controls. Here we report an association between MDR1 alleles, polymorphisms and haplotypes and refractory CD patients, who do not respond to standard therapy, including patients who develop fistulas. We also report an association with UC and MDR1 polymorphisms in a Slovenian population. Haplotypes significantly associated with diseases were defined by single-nucleotide polymorphisms (SNPs) in exons 12 (1236 C>A), 21(A893S), and 26 (3435 C>T). In addition, two intronic SNPs in LD with the disease haplotype, one in intron 13 (rs2235035) and another in intron 16 (rs1922242), were significantly associated with refractory Crohn (P=0.026, odds ratio (OR) 2.7 and P=0.025, OR 2.8, respectively), as well as with UC (P=0.006, OR 1.8 and P=0.026, OR 1.9, respectively). Our results suggest that MDR1 is a potential target for therapy in refractory CD patients and in patients with UC.

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76 Interestingly, N183S in exon 7, S1140T in exon 26,29 P103L in exon 5, and Q1107P in exon 26 were all identified in apparently healthy individuals. Login to comment

[hide] Twelve novel single nucleotide polymorphisms in AB... Drug Metab Pharmacokinet. 2002;17(6):566-71. Itoda M, Saito Y, Komamura K, Ueno K, Kamakura S, Ozawa S, Sawada J
Twelve novel single nucleotide polymorphisms in ABCB1/MDR1 among Japanese patients with ventricular tachycardia who were administered amiodarone.
Drug Metab Pharmacokinet. 2002;17(6):566-71., [PMID:15618713]

Abstract [show]
Twelve novel single nucleotide polymorphisms (SNPs) were found in the gene encoding the ATP-binding cassette transporter, P-glycoprotein, from 60 Japanese individuals who were administered the anti-antiarrythmic drug, amiodarone. The detected SNPs were as follows: 1) SNP, MPJ6_AB1017 (IVS6-109); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 2) SNP, MPJ6_AB1018 (IVS7+14); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 3) SNP, MPJ6_AB1021 (IVS9-44); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 4) SNP, MPJ6_AB1052 (IVS12+17); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 5) SNP, MPJ6_AB1029 (IVS15-69); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 6) SNP, MPJ6_AB1040 (IVS24+16); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 7) SNP, MPJ6_AB1053 (IVS27-189); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 8) SNP, MPJ6_AB1054 (IVS27-172); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 9) SNP, MPJ6_AB1048 (IVS27-167); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 10) SNP, MPJ6_AB1055 (IVS27-152); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 11) SNP, MPJ6_AB1049 (IVS27-119); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168; 12) SNP, MPJ6_AB1051 (at nucleotide 3751 (exon 28) from the A of the translation initiation codon); GENE NAME, ABCB1; ACCESSION NUMBER, NT_017168. Among these SNPs, only MPJ6_AB1051 resulted in an amino acid alteration, V1251I.

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18 Much eort has been taken to uncover polymorphisms in the ABCB1WMDR1 gene since a synonymous SNP, which correlated with diminished MDR1 expression levels in the human duodenum, was reported by Homeyer et al.7) To date, information on 19 single nucleotide polymorphisms (SNPs) including 7 nonsynonymous ones (N21D, F103L, S400N, A893S, A893T, A999T and Q1107P) for ABCB1WMDR1 have been reported in Caucasians.8,9) ABCB1WMDR1 gene SNPs including intronic10) and 2 nonsynonymous SNPs (E108K, M986V)11,12) were also reported in Japanese population. Login to comment

[hide] Single nucleotide polymorphisms in human P-glycopr... Expert Opin Drug Deliv. 2006 Jan;3(1):23-35. Dey S
Single nucleotide polymorphisms in human P-glycoprotein: its impact on drug delivery and disposition.
Expert Opin Drug Deliv. 2006 Jan;3(1):23-35., [PMID:16370938]

Abstract [show]
Drug efflux pumps belong to a large family of ATP-binding cassette transporter proteins. These pumps bind their substrate and export it through the membrane using energy derived from ATP hydrolysis. P-glycoprotein, the main efflux pump in this family, is expressed not only in tumour cells but also in normal tissues with excretory function (liver, kidney and the intestine). It has a broad specificity of substrates and plays an important role in drug delivery and disposition. Recently, genetic screening of P-glycoprotein has yielded multiple single nucleotide polymorphisms, which seem to alter transporter function and expression. This review discusses the various polymorphisms of this gene and its impact on drug disposition and diseases.

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123 Location Position Mutation Effect Promoter 5`/-41 A→G Noncoding Exon 1a Exon 1a/-145 C→G Noncoding Exon 1b Exon 1b/-129 T→C Noncoding Intron 1 Exon 2/-4 C→T Noncoding Intron 1 Exon 2/-1 G→A Initiation of translation Exon 2 Exon 2/61 A→G Asn21Asp Intron 4 Exon 5/-35 G→C Intron 4 Exon 5/-25 G→T Exon 5 Exon 5/307 T→C Phe103Leu Intron 6 Exon 6/+139 C→T Intron 6 Exon 6/+145 C→T Exon 7 Exon 7/548 A→G Asn183Ser Exon 11 Exon 11/1119 G→A Ser400Asn Exon 12 Exon 12/1236 C→T Silent base change Intron 12 Exon 12/+44 C→T Exon 13 Exon 13/1474 C→T Arg492Cys Intron 16 Exon 17/-76 T→A Intron 17 Exon 17/+137 A→G Exon 21 Exon 21/2650 C→T Silent base change Exon 21 Exon 21/2677 G→T G→A Ala893Ser Ala893Thr Exon 24 Exon 24/2956 A→G Met986Val Exon 24 Exon 24/2995 G→A Ala999Thr Exon 26 Exon 26/3320 A→C Gln1107Pro Exon 26 Exon 26/3396 C→T Silent base change Exon 26 Exon 26/3421 T→A Ser1141Thr Exon 26 Exon 26/3435 C→T Silent base change Exon 28 Exon 28/4030 G→C Exon 28 Exon 28/4036 A→G The positions of the polymorphism are from the first base of the ATG start codon set to 1. Login to comment
129 Lastly, rare SNPs located in exon 7 (A548G, Asn183Ser), exon 13 (C1474T, Arg492Cys) and exon 26 (A3320C, Gln1107Pro) leading to amino acid changes have been reported [76,79,96,97]. Login to comment

[hide] MDR1 genotype-related pharmacokinetics: fact or fi... Drug Metab Pharmacokinet. 2005 Dec;20(6):391-414. Sakaeda T
MDR1 genotype-related pharmacokinetics: fact or fiction?
Drug Metab Pharmacokinet. 2005 Dec;20(6):391-414., [PMID:16415525]

Abstract [show]
Multidrug resistant transporter MDR1/P-glycoprotein, the gene product of MDR1, is a glycosylated membrane protein of 170 kDa, belonging to the ATP-binding cassette superfamily of membrane transporters. A number of various types of structurally unrelated drugs are substrates for MDR1, and MDR1 and other transporters are recognized as an important class of proteins for regulating pharmacokinetics. The first investigation of the effects of MDR1 genotypes on pharmacotherapy was reported in 2000; a silent single nucleotide polymorphism (SNP), C3435T in exon 26, was found to be associated with the duodenal expression of MDR1, and thereby the plasma concentration of digoxin after oral administration. In the last 5 years, clinical studies have been conducted around the world on the association of MDR1 genotype with MDR1 expression and function in tissues, and with the pharmacokinetics and pharmacodynamics of drugs; however, there are still discrepancies in the results on C3435T. In 1995, a novel concept to predict in vivo oral pharmacokinetic performance from data on in vivo permeability and in vitro solubility has been proposed, and this Biopharmaceutical Classification System strongly suggested that the effects of intestinal MDR1 on the intestinal absorption of substrates is minimal in the case of commercially available oral drugs, and therefore MDR1 genotypes are little associated with the pharmacokinetics after oral administration. This review summarizes the latest reports for the future individualization of pharmacotherapy based on MDR1 genotyping, and attempts to explain discrepancies.

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29 Representative genetic polymorphisms in MDR1 Position Location EŠect A1aW-41G intron noncoding C-145G exon 1a noncoding T-129C (T12C) exon 1b noncoding C-4T exon 2 noncoding G-1A exon 2 noncoding A61G exon 2 Asn21Asp G5W-25T intron G5W-35C intron T307C exon 5 Phe103Leu C6W＋139T intron C6W＋145T intron A548G exon 7 Asn183Ser G1199A exon 11 Ser400Asn C1236T exon 12 silent C12W＋44T intron C1474T exon 13 Arg492Cys T17W-76A intron A17W＋137G intron C2650T exon 21 silent G2677A,T exon 21 Ala893Thr (G2677A) Ala893Ser (G2677T) A2956G exon 24 Met986Val G2995A exon 24 Ala999Thr A3320C exon 26 Gln1107Pro C3396T exon 26 silent T3421A exon 26 Ser1141Thr C3435T exon 26 silent G4030C exon 28 silent A4036G exon 28 silent See references 27, 32-36. Login to comment

[hide] P-glycoprotein: tissue distribution, substrates, a... Handb Exp Pharmacol. 2011;(201):261-83. Cascorbi I
P-glycoprotein: tissue distribution, substrates, and functional consequences of genetic variations.
Handb Exp Pharmacol. 2011;(201):261-83., [PMID:21103972]

Abstract [show]
P-glycoprotein (ABCB1, MDR1) belongs to the ABC transporter family transporting a wide range of drugs and xenobiotics from intra- to extracellular at many biological interfaces such as the intestine, liver, blood-brain barrier, and kidney. The ABCB1 gene is highly polymorphic. Starting with the observation of lower duodenal protein expression and elevated digoxin bioavailability in relation to the 3435C>T single nucleotide polymorphism, hundreds of pharmacokinetic and outcome studies have been performed, mostly genotyping 1236C>T, 2677G>T/A, and 3435C>T. Though some studies pointed out that intracellular concentrations of anticancer drugs, for example, within lymphocytes, might be affected by ABCB1 variants resulting in differential outcome, current knowledge of the functional significance genetic variants of ABC membrane transporters does not allow selection of a particular SNP to predict an individual's pharmacokinetics.

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13 Absence of the gene, as being the case in double-knockout mice, is conformable N21D S400N A893S/T Q1107P 3435C>T1236T>C N183S R492C S1141T NBD1 NBD2 Intracellular (e.g. lymphocyte) Extracellular M986V Fig. 1 Two-dimensional structure of ABCB1 with locations of amino acid replacements and two frequent synonymous SNPs, NBD ¼ nucleotide binding domain [adapted from Cascorbi and Haenisch (2010)] Inducer intra cellular ABCB1 Transkription Translation ABCB1 (P-gp) luminal Fig. 2 Induction of ABCB1 via the nuclear PXR/RXR receptor leading to accelerated extrusion of P-glycoprotein substrates with life. Login to comment
81 Table 2 Frequency of ABCB1 genetic variants in Caucasians, position on DNA, putative effect, and frequencies [according to Cascorbi (2006) and Cascorbi and Haenisch (2010)] Position Amino acid or effect Frequency of the variant allele Association to expression, kinetics or drug response 50 -flanking À2903 T>C 0.02a 50 -flanking À2410 T>C 0.10a Decreased mRNAa 50 -flanking À2352 G>A 0.28a 50 -flanking À1910 T>C 0.10a 50 -flanking À1717 T>C 0.02a 50 -flanking À1325 A>G 0.02a 50 -flanking À934 A>G 0.10a 50 -flanking À692 T>C 0.10a Decreased mRNAa 50 -flanking À41 A>G 0.09b IVS 1a À145 C>G 0.02b IVS 1b À129 T>C 0.06b IVS 1b 12 T>C 0.06c IVS 2 À1 G>A 0.09d c. 61 A>G N21D 0.11d IVS 5 À35 G>C Intronic 0.006c IVS 5 À25 G>T Intronic 0.16c IVS 6 þ139 C>T Intronic 0.37d c. 548 A>G N183S 0.01e c. 571 G>A G191R 0.07f Reduced chemotherapy resistancef c. 1199 G>A S400N 0.05d c. 1199 C>T S400I 0.02g Elevated activityg c. 1236 C>T Synonymous 0.41d Increased imatinib disposition and therapy responseh IVS 12 þ44 C>T Intronic 0.05d c. 1474 C>T R492C 0.01e IVS 17 À76 T>A Intronic 0.46d IVS 17 þ137 A>G Intronic 0.006c c. 2650 C>T Synonymous 0.03e c. 2677 G>T/A A893S/T 0.42d /0.02d In vitro increased vmax,i increased imatinib response in CMLh c. 2956 A>G M986V 0.005b c. 3320 A>C Q1107P 0.002d c. 3396 C>T Synonymous 0.03c c. 3421 T>A S1141T 0.00c c. 3435 C>T Synonymous 0.54d Decreased mRNA and protein expression,e, k decreased in vitro transport,l no effect on expression and bioavailability of talinolol,m no effect on in vitro transport,n, o decreased digoxin (continued) 4.2.1 Digoxin The heart glycoside digoxin is widely accepted as typical P-glycoprotein substrate. Login to comment

[hide] An update on ABCB1 pharmacogenetics: insights from... Pharmacogenomics J. 2011 Oct;11(5):315-25. doi: 10.1038/tpj.2011.16. Epub 2011 May 31. Wolf SJ, Bachtiar M, Wang J, Sim TS, Chong SS, Lee CG
An update on ABCB1 pharmacogenetics: insights from a 3D model into the location and evolutionary conservation of residues corresponding to SNPs associated with drug pharmacokinetics.
Pharmacogenomics J. 2011 Oct;11(5):315-25. doi: 10.1038/tpj.2011.16. Epub 2011 May 31., [PMID:21625253]

Abstract [show]
The human ABCB1 protein, (P-glycoprotein or MDR1) is a membrane-bound glycoprotein that harnesses the energy of ATP hydrolysis to drive the unidirectional transport of substrates from the cytoplasm to the extracellular space. As a large range of therapeutic agents are known substrates of ABCB1 protein, its role in the onset of multidrug resistance has been the focus of much research. This role has been of particular interest in the field of pharmacogenomics where genetic variation within the ABCB1 gene, particularly in the form of single nucleotide polymorphisms (SNPs), is believed to contribute to inter-individual variation in ABCB1 function and drug response. In this review we provide an update on the influence of coding region SNPs within the ABCB1 gene on drug pharmacokinetics. By utilizing the crystal structure of the mouse ABCB1 homolog (Abcb1a), which is 87% homologous to the human sequence, we accompany this discussion with a graphical representation of residue location for amino acids corresponding to human ABCB1 coding region SNPs. Also, an assessment of residue conservation, which is calculated following multiple sequence alignment of 11 confirmed sequences of ABCB1 homologs, is presented and discussed. Superimposing a 'heat map' of residue homology to the Abcb1a crystal structure has permitted additional insights into both the conservation of individual residues and the conservation of their immediate surroundings. Such graphical representation of residue location and conservation supplements this update of ABCB1 pharmacogenetics to help clarify the often confounding reports on the influence of ABCB1 polymorphisms on drug pharmacokinetics and response.

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48 Four of the 12 associated nsSNPs (E3/61A4G, E5/266C4T, E17/1985T4C and E17/2005C4T) cannot be mapped to the mouse crystal Table 1 Genetic conservation of amino acids corresponding to ABCB1 coding region SNPs 1 - rs28381804 E3/49T>C (F17L) F17 W16 S16 Y17 Y35 F39 - A42 - - G11 - - 2 - rs41304191 E3/55C>T (L19L) L19 M18 M18 I19 G37 P41 - E44 - - L13 - - 3 - rs76199854 E3/57G>A (L19L) L19 M18 M18 I19 G37 P41 - E44 - - L13 - - --51I--64H-34K93N12N02K02K12N)D12N(G>A16/3E4652829sr-4 7.832.8105P12A01K88D61D18T07T55S34G34N44N)S44N(G>A131/5E3812021sr1sn5 6 ns2 rs41315618 E5/178A>C (I60L) I60 I59 I59 A71 I86 A97 G32 G104 K26 N37 L66 27.3 46.6 1.924.6368N75G64N421Y25G711I601I19V97A97A08A)E08A(A>C932/5E5652829sr3sn7 8 - rs35810889 E5/266C>T (M89T) - M89 F89 S85 T96 I112 - - - - - - - - 9 ns4 rs61607171 E7/431T>C (I144T) TM2 I144 I145 I140 V152 N168 I176 A98 A172 L93 V97 L124 36.4 40.9 2.645.45841G121T711V691A221T002S291S671A461V961V861V)I861V(A>G205/7E32622116sr5sn01 11 s1 rs1128500 E8/540C>T (S180S) S180 S181 S176 S188 E204 S212 L136 N208 E129 E133 E160 27.3 42.0 12 ns6 rs60419673 E8/548A>G (N183S) N183 N184 N179 N191 K207 E215 Q139 Q211 K132 A136 S163 27.3 39.9 9.045.54561G831S431F312G141F712G902G391G181G681G581G)V581G(T>G455/8E1058211sr7sn31 14 s2 rs1128502 E8/555A>T (G185G) G185 G186 G181 G193 G209 G217 F141 G213 F134 S138 G165 45.5 40.9 15 s3 rs2235022 E9/729A>G (E243E) E243 E244 E239 E251 E267 E275 I199 Q271 R192 M196 S223 18.2 33.3 16 s4 rs28381867 E9/738G>A (A246A) A246 A247 A242 A254 R270 M278 E202 V274 A195 T199 Y226 9.1 34.5 17 ns8 rs36008564 E9/781A>G (I261V) C-NBD (Internal) I261 I262 I257 V267 I285 I293 V217 I289 I210 H214 I241 36.4 50.3 18 s5 rs80153317 E10/879T>C (I293I) TM5 I293 I294 I289 I301 L317 M325 L249 I321 R242 S246 F273 18.2 36.3 19 ns9 rs2229109 E12/1199G>A (S400N) N-NBD (Internal) S400 S401 S396 N408 T424 Q439 T355 V428 Q348 T350 H386 18.2 60.7 20 s6 rs1128503 E13/1236C>T (G412G) N-NBD (External) G412 G413 G408 G420 G436 K451 D367 N440 D359 N361 D398 27.3 55.9 21 s7 rs35068177 E13/1308A>G (T436T) T436 T437 T432 T44 I460 C475 V391 I464 L383 I385 I422 54.5 64.6 22 s8 rs41311775 E15/1326G>A (R442R) R442 R443 R438 R450 R466 R481 R397 R470 R389 R391 R428 100.0 54.5 23 s9 rs35633772 E15/1617C>T (I539I) I539 I540 I535 I547 I563 I578 I494 I576 L486 I489 I571 90.9 65.8 24 s10 rs60247941 E15/1632C>T (A544A) A544 A545 A540 A552 A568 A583 A499 A581 I491 A494 A576 63.6 65.1 25 s11 rs2235012 E15/1662G>C (L554L) L554 L555 L550 L562 L578 L593 L509 L591 L501 L504 L586 100.0 73.6 26 s12 rs56871767 E15/1674G>A (T558T) T558 T559 T554 T566 T582 T597 T513 T595 T505 T508 T590 100.0 78.7 27 s13 rs59697741 E15/1695C>T (S565S) S565 S566 S561 S573 S589 S604 S520 S602 S512 S515 S597 100.0 75.4 28 ns10 rs28381902 E15/1696G>A (E566K) E566 E567 E562 E574 E590 E605 E521 E603 E513 E516 E598 100.0 76.6 29 ns11 rs28381914 E16/1777C>T (R593C) R593 R594 R589 R601 R617 R632 R548 R630 T540 E543 R627 54.5 67.3 30 ns12 rs56107566 E16/1778G>A (R593H ) R593 R594 R589 R601 R617 R632 R548 R630 T540 E543 R627 54.5 67.3 31 s14 rs28381915 E16/1794C>T (I598I) I598 I599 I594 I606 I622 I637 I553 I635 I545 I548 I632 100.0 65.5 32 ns13 rs2235036 E16/1795G>A (A599T) A599 A600 A595 A607 I623 V638 C554 V636 V546 V549 F633 54.5 63.6 33 ns14 rs57001392 E16/1837G>T (D613Y) N-NBD (External) D613 D614 D609 S621 R637 Q652 E568 N650 R560 N563 D677 45.5 60.5 -0.0637E--807A516E896K496M176E856L366L266L)R266L(C>T5891/71E06975653sr-43 35 - rs35023033 E17/2005C>T (R669C) R669 R670 R665 R678 I702 D705 S662 T715 - - N743 0.0 - 36 - rs59340265 E17/2037C>T (D679D) D679 D680 D675 N688 D712 N715 S632 N725 - - E753 9.1 - 37 ns15 rs41316450 E18/2207T>A (I736K) TM7 I736 I737 V732 I745 M779 I771 V682 I820 I37 L48 V814 72.7 36.7 38 ns16 rs77144566 E19/2281A>C (A761S) TM8 A761 V763 I757 A769 V802 I796 G706 I844 I647 G655 L836 63.6 42.1 39 ns17 rs41305517 E21/2398G>A (D800N) C-NBD (Internal) D800 D801 D796 D808 H841 D835 E745 D883 S108 P112 E875 9.1 45.4 40 ns18 rs2235039 E21/2401G>A (V801M) C-NBD (External) V801 V802 V797 M809 I842 V836 V746 V884 A109 V113 M876 63.6 47.6 2.035.54409L931S531I219S447V468T078I738T528T038I928I)V928I(G>A5842/22E1852302sr91sn14 42 s15 rs28381966 E22/2505A>G (V835V) V835 V836 V831 L843 T876 T870 L780 T918 N141 T145 F911 45.5 33.0 43 ns20 rs28381967 E22/2506A>G (I836V) I836 I837 I832 I844 V877 I871 L781 V919 I142 V146 F911 63.6 28.5 7.448.18429M951M551I239L497I488D098I758I548I058I948I)M948I(G>A7452/22E03150163sr12sn44 45 s16 rs9282563 E22/2650C>T (L884L) L884 L885 L880 K892 V925 M919 R829 E967 R190 K194 I959 27.3 31.2 7.535.54289P302V991V679S838S829C439S109A988S498A398S)T/A398S(A/T>G7762/22E2852302sr22sn64 4.834.631801M203T892V5701F739G7201L5301T0001S889S399S299S)N299S(A>G5792/52E72194865sr32sn74 5.633.729801E903Q503T2801T449V4301Q2401A7001A599A0001A999A)T999A(A>G5992/52E48725527sr42sn84 49 s17 rs2235044 E26/3084G>A (P1028P) P1028 P1029 P1024 P1036 - P1063 P973 V1111 P332 V334 I1117 0.0 33.0 50 ns25 rs28401798 E26/3151C>G (P1051A) P1051 P1052 P1047 K1059 E1093 Q1086 I996 K1135 P355 P357 P1142 18.2 57.6 51 ns26 rs2707944 E26/3188G>C (G1063A) G1063 G1064 G1059 G1071 G1105 G1098 G1008 G1147 G367 G369 K1154 45.5 53.8 52 s18 rs2707943 E26/3189C>G (G1063G) G1063 G1064 G1059 G1071 G1105 G1098 G1008 G1147 G367 G369 K1154 45.5 53.8 53 ns27 rs74755520 E26/3222A>C (C1074W) C-NBD (Internal) C1074 C1075 C1070 C1082 C1116 C1109 S1019 C1158 G378 S380 S1165 63.6 67.8 54 ns28 rs57521326 E26/3262G>A (D1088N) D1088 D1089 D1084 D1096 D1130 D1123 D1033 D1172 D392 D394 D1179 100.0 53.9 55 ns29 rs41309225 E27/3295A>G (K1099E) K1099 K1100 K1095 I1107 S1141 C1134 R1044 V1183 H403 H405 I1237 18.2 38.5 56 ns30 rs55852620 E27/3320A>C (Q1107P) Q1107 Q1108 Q1103 Q1115 E1149 T1142 R1052 N1191 G411 A413 R1245 27.3 43.7 57 ns31 rs35730308 E27/3322T>C (W1108R) W1108 Q1109 W1104 Q1116 H1150 N1143 S1053 D1192 S412 S414 D1246 27.3 43.5 58 s19 rs34748655 E27/3396C>T (A1132A) C-NBD (Internal) A1132 A1133 A1128 A1140 I1174 S1167 M1077 V1216 L436 A438 K1270 27.3 56.8 59 ns32 rs41309228 E27/3410G>T (S1137I ) S1137 S1138 S1133 S1145 P1179 A1172 S1082 S1220 P440 E443 - 18.2 41.8 60 ns33 rs2229107 E27/3421T>A (S1141T) S1141 S1142 S1137 S1149 T1183 T1176 D1086 S1224 D444 R447 T1277 45.5 50.9 61 s20 rs1045642 E27/3435C>T (I1145I) C-NBD (Internal) I1145 I1146 I1141 I1153 V1187 I1180 I1090 M1228 V447 I450 V1281 72.7 57.6 62 ns34 rs59241388 E28/3502A>G (K1168E) K1168 R1169 R1164 R1176 R1210 R1203 C1113 L1251 E470 V473 N1304 27.3 61.9 63 ns35 rs41309231 E29/3669A>T (E1223D) E1223 E1224 E1219 E1231 E1265 E1258 V1168 Q1306 K525 K528 D1359 27.3 60.2 64 s21 rs2235051 E29/3747C>G (G1249G) C-NBD (Internal) G1249 G1250 G1245 G1257 G1291 G1284 G1194 G1332 G551 G554 T1392 63.6 63.0 65 ns36 rs45456698 E29/3751G>A (V1251I) V1251 V1252 V1247 V1259 I1293 V1286 V1196 I1334 I553 I556 V1394 81.8 59.2 4.957.279931T165T855T9331T1021N1921D8921T4621T2521T7521T6521T)K6521T(A>C7673/92E93412753sr73sn66 C-NBD (External) C-NBD (External) C-NBD (External) C-NBD (External) TM4 - TM9 TM10 - TM1 S. aureus TM12 N-NBD (Internal) N-NBD (External) N-NBD (Internal) C-NBD (External) TM3 C. elegans D. melanoga ster A. thaliana S. pombe # SNP (amino acid substitution) Mapped to Abcb1a domain (internal/external surface) rsNo Conservation (%)a H. Sapiens C. l. Familiaris M. Musculus G. gallus P. falciparum Amino acid residue housing SNP Individual Regional 3 structure E. coli a The conservation of residues corresponding to all coding regions SNPs was obtained following multiple sequence alignment of 11 confirmed ABCB1 homolog protein sequences. Login to comment

[hide] MDR1 gene polymorphisms and clinical relevance. Yi Chuan Xue Bao. 2006 Feb;33(2):93-104. Li YH, Wang YH, Li Y, Yang L
MDR1 gene polymorphisms and clinical relevance.
Yi Chuan Xue Bao. 2006 Feb;33(2):93-104., [PMID:16529292]

Abstract [show]
In vivo and in vitro studies have demonstrated that P-glycoprotein (P-gp) plays a very significant role in the ADME processes (absorption, distribution, metabolism, excretion) and drug-drug interaction (DDI) of drugs in humans. P-gp is the product of multidrug resistance gene (MDR1/ABCB1). Pharmacogenomics and pharmacogenetics studies have revealed that genetic polymorphisms of MDR1 are associated with alteration in P-gp expression and function in different ethnicities and subjects. By now, 50 single nucleotide polymorphisms (SNPs) and 3 insertion/deletion polymorphisms have been found in the MDR1 gene. Some of them, such as C3435T, have been identified to be a risk factor for numerous diseases. It is believed that further understanding of the physiology and biochemistry of P-gp with respect to its genetic variations may be important for individualized pharmacotherapy. Therefore, based on the latest public information and our studies, this review focuses on the following four aspects: 1) the impact of P-gp on pharmacokinetics; 2) MDR1 genetic polymorphisms and their impacts on pharmacogenetics; 3) relationship between altered P-gp expression and function and the MDR1(C3435T) SNP, and 4) relevance of MDR1 polymorphisms to certain human diseases.

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39 Four SNPs are at wobble positions with no amino acid changes [C1236T (exon 12), C2650T (exon 21) and C343ST, C3396T (both in exon26)I. Subsequently, a screen of 461 German Caucasians for allele and genotype distribution further revealed two rare mutations (G2677A: Ala893Thr; and A3320C: Gln1107Pro) 13". Login to comment
46 The 16.18.19,35] B@%fW Acta Genetica Sinica Vo1.33 No.2 2006 nonsynonymous G1199A (Ser400Asn) in exon 11 brings about a significant size change, and depending on the pH and isoelectric environment of the residue, may lead to a charge change in the protein. Login to comment