{{Rsnum
|rsid=1128503
|Gene=ABCB1
|Chromosome=7
|position=87550285
|Orientation=minus
|ReferenceAllele=T
|GMAF=0.4219
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
|Gene_s=ABCB1
}}{{ population diversity
| geno1=(C;C)
| geno2=(C;T)
| geno3=(T;T)
| CEU | 26.5 | 56.6 | 16.8
| HCB | 11.8 | 37.5 | 50.7
| JPT | 17.7 | 47.8 | 34.5
| YRI | 76.2 | 23.1 | 0.7
| ASW | 61.4 | 36.8 | 1.8
| CHB | 11.8 | 37.5 | 50.7
| CHD | 9.2 | 45.0 | 45.9
| GIH | 13.9 | 54.5 | 31.7
| LWK | 78.2 | 20.9 | 0.9
| MEX | 24.1 | 58.6 | 17.2
| MKK | 73.1 | 24.4 | 2.6
| TSI | 36.3 | 43.1 | 20.6
| HapMapRevision=28
}}[[rs1128503]] is a SNP in the transporter P-glycoprotein (P-gp) 170, encoded by the [[ABCB1]] (also known as MDR1) gene. [[Methadone]] is a substrate of this protein, so variants may affect the efficacy and optimal dosage of this drug as used for treating opiate dependence.

A study of 98 methadone-maintaining patients concluded that the higher (>150 mg/day) and lower (< or =150 mg/day) [[methadone]] dose groups differed significantly in their [[rs1128503]] status (experiment-wise p = 0.0325). Furthermore, individuals with the 3-locus genotype pattern (T;T)-(T;T)-(T;T) for SNPs [[rs1045642]], [[rs2032582]] and [[rs1128503]], respectively, had an approximately 5-fold chance of requiring the 'higher' methadone dose, while individuals heterozygous for these three SNPs have an approximately 3-fold chance of stabilizing at the 'lower' methadone dose (point-wise p-value = 0.026).{{PMID|18424454|OA=1
}}

{{ neighbor
| rsid = 2235035
| distance = 515
}}

{{PMID Auto
|PMID=19107781
|Title=Associations between ABCB1/MDR1 gene polymorphisms and Crohn's disease: a gene-wide study in a pediatric population
}}

{{PharmGKB
|RSID=rs1128503
|Name_s=ABCB1:2677G>T/A, mRNA 3095G>T/A, Ala893Ser/Thr
|Gene_s=ABCB1
|Feature=Exon/Syn
|Evidence=PubMed ID:12781336
|Annotation=Risk or phenotype-associated allele: None. Phenotype: Efflux of P-glycoprotein substrates (verapamil; digoxin; vinblastine; cyclosporin A) in vitro were not significantly affected by combined mutations for rs1128503 (2677G>T/A) and rs1045642 (3435C>T) in LLC-PK1 cell lines. Study size: Triplicate cell assays. Study population/ethnicity: N/A. Significance metric(s): Not significant, p > 0.05. Type of association: FA
|Drugs=cyclosporine; digoxin; verapamil; vinblastine
|Drug Classes=
|Diseases=
|Curation Level=Curated
|PharmGKB Accession ID=PA165110747
}}

{{PMID Auto
|PMID=19437139
|Title=ABCB1 single nucleotide polymorphisms in the Brazilian population
}}

{{PharmGKB
|RSID=rs1128503
|Name_s=ABCB1:1236C>T
|Gene_s=ABCB1
|Feature=Exon/Syn
|Evidence=Web Resource:http://www.pharmgkb.org/search/annotatedGene/abcb1/variant.jsp#ImportantVariantInformationforABCB1-1236
|Annotation=This SNP is well known, but there is no clear consensus on its significance for drug disposition, response or toxicity.
|Drugs=
|Drug Classes=
|Diseases=
|Curation Level=In-Depth
|PharmGKB Accession ID=PA161145209
}}

{{PharmGKB
|RSID=rs1128503
|Name_s=ABCB1:1236T>C, mRNA 1654T>C, Gly412Gly
|Gene_s=ABCB1
|Feature=Exon/Syn
|Evidence=PubMed ID:18717915
|Annotation=peak blood concentration of cyclosporin A (CsA) was significantly lower in myasthenia gravis patients harboring the 1236 T allele; and trough CsA levels were significantly greater in 1236 TT homozygotes versus CC homozygotes
|Drugs=cyclosporine
|Drug Classes=
|Diseases=Myasthenia Gravis
|Curation Level=Curated
|PharmGKB Accession ID=PA164944056
}}

{{PharmGKB
|RSID=rs1128503
|Name_s=ABCB1:1236C>T
|Gene_s=ABCB1
|Feature=Exon/Syn
|Evidence=PubMed ID:18377430
|Annotation=Risk or phenotype-associated allele: T. Phenotype: A haplotype of ABCB1 c.1236C>T, c.2677G>A/T, and c.3435C>T (rs1128503, rs2032582 and rs1045642) was associated with increased drug exposure and reduced clearance. Study size: . Study population/ethnicity: Asian patients with Breast Neoplasms treated with doxorubicin. Significance metric(s): p = 0.03 (exposure); p= 0.01 (clearance). Type of association: PK.
|Drugs=doxorubicin
|Drug Classes=
|Diseases=Breast Neoplasms
|Curation Level=Curated
|PharmGKB Accession ID=PA165291809
}}

{{PharmGKB
|RSID=rs1128503
|Name_s=ABCB1 1236C>T, ABCB1:1236C>T
|Gene_s=ABCB1
|Feature=Exon/Syn
|Evidence=PubMed ID:19997080
|Annotation=Risk or phenotype-associated allele: T Phenotype: Carriers of the T variant of ABCB1:1236C>T had lower Autism Treatment Evaluation Checklist (ATEC) scores, indicating improved symptoms and response to risperidone, than CC homozygotes. Study size: 45 Study population/ethnicity: Children with Autism receiving risperidone Significance metric(s): p = 0.002 Type of association: PD
|Drugs=risperidone
|Drug Classes=
|Diseases=Autistic Disorder
|Curation Level=Curated
|PharmGKB Accession ID=PA165111372
}}

{{PharmGKB
|RSID=rs1128503
|Name_s=ABCB1: c.1236T>C, mRNA 1654T>C, p.Gly412Gly; ABCB1*8
|Gene_s=ABCB1
|Feature=Exon/Syn
|Evidence=PubMed ID:15122075
|Annotation=Risk or phenotype-associated allele: rs1128503 TT genotype. Phenotype: Systemic exposure of tipifarnib, based on plasma AUC levels, were 46.5% higher for patients homozygous for ABCB1*8 (3435TT) compared to the CT and CC genotypes. Study size: 28 (16 male). Study population/ethnicity: Caucasian cancer patients, aged 34-75. Significance metric(s): p = 0.047. Type of association: GN; PK
|Drugs=Tipifarnib
|Drug Classes=
|Diseases=
|Curation Level=Curated
|PharmGKB Accession ID=PA165111310
}}

{{omim
|id=610064
|rsnum=1128503
}}

{{PMID Auto
|PMID=21790905
|Title=CYP2B6 SNPs are associated with methadone dose required for effective treatment of opioid addiction
}}

{{PMID Auto
|PMID=22015057
|Title=Single nucleotide polymorphism associations with response and toxic effects in patients with advanced renal-cell carcinoma treated with first-line sunitinib: a multicentre, observational, prospective study
}}

{{PMID Auto
|PMID=22110582
|Title=Association of MDR1 Gene SNPs and Haplotypes with the Tacrolimus Dose Requirements in Han Chinese Liver Transplant Recipients
|OA=1
}}

{{PMID Auto
|PMID=21705081
|Title=Multidrug resistance gene expression and ABCB1 SNPs in plasma cell myeloma
}}

{{PMID Auto
|PMID=21806386
|Title=Pharmacogenetics of calcineurin inhibitors in Brazilian renal transplant patients
}}

{{PMID Auto
|PMID=22358301
|Title=ABCB1 genetic variation and P-glycoprotein expression/activity in a cohort of Brazilian acute myeloid leukemia patients
}}

{{PMID Auto
|PMID=22416375
|Title=[Genetic performance criteria valproate in patients with epilepsy]
}}

{{PMID|15197162|OA=1
}} Identifying candidate causal variants responsible for altered activity of the ABCB1 multidrug resistance gene.

{{PMID|16999857|OA=1
}} ABCB1 genotypes and haplotypes in patients with dementia and age-matched non-demented control patients.

{{PMID|17548681}} MDR1 gene variants, indoor insecticide exposure, and the risk of childhood acute lymphoblastic leukemia.

{{PMID|17913323}} ABCB1 (MDR1) gene polymorphisms are associated with the clinical response to paroxetine in patients with major depressive disorder.

{{PMID|18213362|OA=1
}} Multiplexed genotyping of ABC transporter polymorphisms with the Bioplex suspension array.

{{PMID|18547414|OA=1
}} Genotyping panel for assessing response to cancer chemotherapy.

{{PMID|18698231|OA=1
}} Polymorphisms affecting gene transcription and mRNA processing in pharmacogenetic candidate genes: detection through allelic expression imbalance in human target tissues.

{{PMID|18725235|OA=1
}} Bidirectional translational research: Progress in understanding addictive diseases.

{{PMID|18812236}} No association of ABCB1 polymorphisms with drug-refractory epilepsy in a north Indian population.

{{PMID|19155191|OA=1
}} Opiate and cocaine addiction: from bench to clinic and back to the bench.

{{PMID|19285141|OA=1
}} Genetic determinants of target and novelty-related event-related potentials in the auditory oddball response.

{{PMID|19694740|OA=1
}} No significant effect of ABCB1 haplotypes on the pharmacokinetics of fluvastatin, pravastatin, lovastatin, and rosuvastatin.

{{PMID|19740399|OA=1
}} Influence of ABCB1 polymorphisms and haplotypes on tacrolimus nephrotoxicity and dosage requirements in children with liver transplant.

{{PMID|19844206|OA=1
}} Sequence variations of ABCB1, SLC6A2, SLC6A3, SLC6A4, CREB1, CRHR1 and NTRK2: association with major depression and antidepressant response in Mexican-Americans.

{{PMID|20170205}} Effect of CYP3A and ABCB1 single nucleotide polymorphisms on the pharmacokinetics and pharmacodynamics of calcineurin inhibitors: Part I.

{{PMID|20214406}} Effect of CYP3A and ABCB1 single nucleotide polymorphisms on the pharmacokinetics and pharmacodynamics of calcineurin inhibitors: Part II.

{{PMID|20354687|OA=1
}} Explaining variability in ciclosporin exposure in adult kidney transplant recipients.

{{PMID|20389299|OA=1
}} Pazopanib-induced hyperbilirubinemia is associated with Gilbert's syndrome UGT1A1 polymorphism.

{{PMID|20533057|OA=1
}} ABCB1/MDR1 gene polymorphisms as a prognostic factor in colorectal cancer.

{{PMID|21102498}} Cytochrome P450 genetic polymorphisms influence the serum concentration of calcineurin inhibitors in allogeneic hematopoietic SCT recipients.

{{PMID|21172166|OA=1
}} Pharmacogenetics of antidepressant response.

{{PMID|21553324}} Polymorphisms of the MDR1 and MIF genes in children with nephrotic syndrome.

{{PMID|21840870}} Association of ABCB1, 5-HT3B receptor and CYP2D6 genetic polymorphisms with ondansetron and metoclopramide antiemetic response in Indonesian cancer patients treated with highly emetogenic chemotherapy.

{{PMID|21896346}} Polymorphisms in genes that regulate cyclosporine metabolism affect cyclosporine blood levels and clinical outcomes in patients who receive allogeneic hematopoietic stem cell transplantation.

{{PMID|22134106}} ABCB1 haplotype is associated with major molecular response in chronic myeloid leukemia patients treated with standard-dose of imatinib.

{{PMID|22136368}} Influence of genomic ancestry on the distribution of SLCO1B1, SLCO1B3 and ABCB1 gene polymorphisms among Brazilians.

{{PMID|22306099}} Association between the functional polymorphism (C3435T) of the gene encoding P-glycoprotein (ABCB1) and major depressive disorder in the Japanese population.

{{PMID|22569204|OA=1
}} PharmGKB summary: phenytoin pathway.

{{GET Evidence
|impact=pharmacogenetic
|qualified_impact=Insufficiently evaluated pharmacogenetic
|inheritance=unknown
|quality_scores=Array
|dbsnp_id=rs1128503
|overall_frequency_n=6945
|overall_frequency_d=10758
|overall_frequency=0.645566
|n_genomes=46
|n_genomes_annotated=0
|n_haplomes=72
|n_articles=5
|n_articles_annotated=1
|in_pharmgkb=Y
|autoscore=1
|webscore=N
}}

{{PMID Auto
|PMID=23188198
|Title=ABCB1 polymorphism predicts escitalopram dose needed for remission in major depression
|OA=1
}}

{{PMID Auto
|PMID=23546964
|Title=Frequency of MDR1 single nucleotide polymorphisms in a Jordanian population, including a novel variant
}}

{{PMID Auto
|PMID=23093106
|Title=Detection of frequent ABCB1 polymorphisms by high-resolution melting curve analysis and their effect on breast carcinoma prognosis
}}

{{PMID Auto
|PMID=23786015
|Title=[Pharmacogenetic criteria drug-resistence epilepsy]
}}

{{PMID Auto
|PMID=23917080
|Title=ABCB1 (MDR1) polymorphisms and ovarian cancer progression and survival: a comprehensive analysis from the Ovarian Cancer Association Consortium and The Cancer Genome Atlas
}}

{{PMID Auto
|PMID=23133420
|Title=Pharmacogenomic Diversity among Brazilians: Influence of Ancestry, Self-Reported Color, and Geographical Origin.
|OA=1
}}

{{PMID Auto
|PMID=23133441
|Title=ABCB1 4036A>G and 1236C>T Polymorphisms Affect Plasma Efavirenz Levels in South African HIV/AIDS Patients.
|OA=1
}}

{{PMID Auto
|PMID=23443032
|Title=Fetal polymorphisms at the ABCB1-transporter gene locus are associated with susceptibility to non-syndromic oral cleft malformations.
}}

{{PMID Auto
|PMID=23462807
|Title=Single-nucleotide polymorphisms associated with outcome in metastatic renal cell carcinoma treated with sunitinib.
|OA=1
}}

{{PMID Auto
|PMID=23896815
|Title=Influence of ATP-binding cassette polymorphisms on neurological outcome after traumatic brain injury
}}

{{PMID Auto
|PMID=25007187
|Title=Genetic polymorphisms in candidate genes predict increased toxicity with methotrexate therapy in Lebanese children with acute lymphoblastic leukemia
}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | FTDNA2}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}