{{Rsnum
|rsid=762551
|Gene=CYP1A2
|Chromosome=15
|position=74749576
|Orientation=plus
|GMAF=0.3522
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(A;A)
|geno2=(A;C)
|geno3=(C;C)
|Gene_s=CYP1A2
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;C)
| geno3=(C;C)
| CEU | 53.1 | 38.1 | 8.8
| HCB | 44.5 | 44.5 | 10.9
| JPT | 35.4 | 48.7 | 15.9
| YRI | 32.7 | 48.3 | 19.0
| ASW | 43.9 | 49.1 | 7.0
| CHB | 44.5 | 44.5 | 10.9
| CHD | 35.8 | 48.6 | 15.6
| GIH | 25.7 | 51.5 | 22.8
| LWK | 20.0 | 54.5 | 25.5
| MEX | 58.6 | 29.3 | 12.1
| MKK | 28.2 | 48.7 | 23.1
| TSI | 39.2 | 47.1 | 13.7
| HapMapRevision=28
}}
[[rs762551]], also known as -164A>C or -163C>A, is a SNP encoding the CYP1A2*1F allele of the [[CYP1A2]] gene. For historic reasons, the [[rs762551]](C) allele is considered the wild-type, even though it is the rarer allele in most populations. The [[rs762551]](A) allele is the "fast metabolizer" allele known as CYP1A2*1F; the (C) allele is by comparison a slower metabolizer of certain substrates (including [[caffeine]]).

In terms of genotypes, only [[rs762551]](A;A) individuals are considered fast metabolizers. Individuals who are [[rs762551]](A;C) heterozygotes or [[rs762551]](C;C) homozygotes are both considered slow metabolizers.

The CYP1A2 gene encodes a member of the cytochrome p450 family of proteins, which metabolize nutrients and drugs. One well known substrate of CYP1A2 is caffeine; individuals who are carry one or more CYP1A2*1C alleles are "slow" caffeine metabolizers, whereas carriers of the variant CYP1A2*1F are "fast" caffeine metabolizers. The same amount of caffeine will therefore tend to have more stimulating effect on CYP1A2 slow metabolizers than on CYP1A2 fast metabolizers.

A study of healthy premenopausal non-hormone using women concluded that drinkers of 3 or more cups of [[coffee]] per day tended to have lower breast volume (smaller breasts), but only if they had at least one [[rs762551]](C) allele (p(interaction)=0.02), which was said to be consistent with reports that coffee protects only C-allele carriers against [[breast cancer]].{{PMID|18813311|OA=1
}}

Another study by this same group looked at coffee consumption as related to [[breast cancer]]. Among 458 such patients (age 25-99 years), [[rs762551]](A;A) women (about 1/2 of the total study) who drank 2 or more cups of coffee per day tended to have a later age at diagnosis compared with low coffee consumption (59.8 versus 52.6 years, p = 0.0004). These patients were also more likely to have ER- tumors than patients with low consumption (14.7% versus 0%, p = 0.018). Coffee consumption had no associations in carriers of a [[rs762551]](C) allele.{{PMID|18398030}}

An independent study of 411 [[BRCA1]] mutation carriers (170 cases and 241 controls) looked at the association between [[breast cancer]], coffee consumption before age 35, and CYP1A2 genotype. While CYP1A2 genotype did not affect breast cancer risk, women with at least one [[rs762551]](C) allele who consumed coffee had a 64% reduction in breast cancer risk, compared with women who never consumed coffee (odds ratio 0.36, CI: 0.18-0.73). No such protective effect was seen in [[rs762551]](A;A) women.{{PMID|17507615}}

A study of 2,000 Costa Ricans who survived a first heart attack observed a general trend between coffee consumption and increased risk among carriers of [[rs762551]](C) alleles, i.e. more coffee led to increased nonfatal heart attack risk. No association was seen for [[rs762551]](A;A) individuals.{{PMID|16522833}}

{{PMID Auto
|PMID=19415745
|Title=Genetic polymorphisms of estrogen metabolizing enzyme and breast cancer risk in Thai women
}}

{{PharmGKB
|RSID=rs762551
|Name_s=CYP1A2*1F; CYP1A2:(-163)C>A
|Gene_s=CYP1A2
|Feature=
|Evidence=PubMed ID:19636338
|Annotation=Risk or phenotype-associated allele: A. Phenotype: CYP1A2*1F/*1F genotype was associated with reduced dose-/body weight-normalized olanzapine serum concentrations compared to homo- and heterozygote carriers of CYP1A2*1A. Study size: 124. Study population/ethnicity: Caucasian; Patients with psychiatric disorders.Type of association: PD.
|Drugs=olanzapine
|Drug Classes=
|Diseases=
|Curation Level=Curated
|PharmGKB Accession ID=PA165109602
}}

{{PharmGKB
|RSID=rs762551
|Name_s=CYP1A2:(-)163C>A; CYP1A2:(-)164C>A; CYP1A2:734C>A; CYP1A2*1F
|Gene_s=CYP1A2
|Feature=
|Evidence=PubMed ID:10233211; PubMed ID:12445035
|Annotation=Very common SNP, high inducibility.
|Drugs=
|Drug Classes=
|Diseases=
|Curation Level=Curated
|PharmGKB Accession ID=PA161145040
}}

{{PharmGKB
|RSID=rs762551
|Name_s=CYP1A2*1F
|Gene_s=CYP1A2
|Feature=
|Evidence=PubMed ID:18496682
|Annotation=A study in 105 patients with rheumatoid arthritis found that patients with the CYP1A2*1F CC genotype had a 9.7-fold higher risk for overall leflunomide-induced toxicity than the carriers of CYP1A2*1F A allele.
|Drugs=leflunomide
|Drug Classes=
|Diseases=Arthritis, Rheumatoid
|Curation Level=Curated
|PharmGKB Accession ID=PA162191314
}}

{{PharmGKB
|RSID=rs762551
|Name_s=CYP1A2*1F
|Gene_s=CYP1A2
|Feature=
|Evidence=PubMed ID:16522833
|Annotation=Carriers of the C allele of this SNP(*1F) are slow metabolizers of caffeine. In a study of Costa Rican Hispanic Americans, the risk of nonfatal Myocardial Infarction increased with coffee intake for *1F carriers.
|Drugs=caffeine
|Drug Classes=
|Diseases=Myocardial Infarction
|Curation Level=Curated
|PharmGKB Accession ID=PA162263496
}}

{{PMID Auto
|PMID=21281405
|Title=Coffee, ADORA2A, and CYP1A2: the caffeine connection in Parkinson's disease
|OA=1
}}

{{PMID Auto
|PMID=22492992
|Title=Caffeine intake and CYP1A2 variants associated with high caffeine intake protect non-smokers from hypertension.
}}

{{PMID Auto
|PMID=22648710
|Title=CYP1A2 and coffee intake and the modifying effect of sex, age, and smoking
}}

{{PMID Auto
|PMID=16172230
|Title=Risk of testicular germ cell cancer in relation to variation in maternal and offspring cytochrome p450 genes involved in catechol estrogen metabolism.
}}

{{PMID Auto
|PMID=17116718
|Title=Dietary phytoestrogen intake is associated with reduced colorectal cancer risk.
|OA=1
}}

{{PMID Auto
|PMID=17160896
|Title=Orofacial cleft risk is increased with maternal smoking and specific detoxification-gene variants.
|OA=1
}}

{{PMID Auto
|PMID=17688403
|Title=Association of serotonin 2A receptor and lack of association of CYP1A2 gene polymorphism with tardive dyskinesia in a Turkish population.
}}

{{PMID Auto
|PMID=18075470
|Title=Association between caffeine intake and risk of Parkinson's disease among fast and slow metabolizers.
}}

{{PMID Auto
|PMID=18268115
|Title=Meat intake, heterocyclic amine exposure, and metabolizing enzyme polymorphisms in relation to colorectal polyp risk.
|OA=1
}}

{{PMID Auto
|PMID=18632753
|Title=Bladder cancer risk and genetic variation in AKR1C3 and other metabolizing genes.
|OA=1
}}

{{PMID Auto
|PMID=18759349
|Title=Coffee, caffeine-related genes, and Parkinson's disease: a case-control study.
}}

{{PMID Auto
|PMID=18798002
|Title=Coffee consumption, genetic susceptibility and bladder cancer risk.
|OA=1
}}

{{PMID Auto
|PMID=18941913
|Title=Coffee intake, variants in genes involved in caffeine metabolism, and the risk of epithelial ovarian cancer.
|OA=1
}}

{{PMID Auto
|PMID=18990750
|Title=Red meat intake, doneness, polymorphisms in genes that encode carcinogen-metabolizing enzymes, and colorectal cancer risk.
|OA=1
}}

{{PMID Auto
|PMID=18992148
|Title=Low-penetrance alleles predisposing to sporadic colorectal cancers: a French case-controlled genetic association study.
|OA=1
}}

{{PMID Auto
|PMID=19287484
|Title=Clique-finding for heterogeneity and multidimensionality in biomarker epidemiology research: the CHAMBER algorithm.
|OA=1
}}

{{PMID Auto
|PMID=19338043
|Title=Genetic polymorphisms in glutathione S-transferases and cytochrome P450s, tobacco smoking, and risk of non-Hodgkin lymphoma.
|OA=1
}}

{{PMID Auto
|PMID=20304699
|Title=Polymorphisms of caffeine metabolism and estrogen receptor genes and risk of Parkinson's disease in men and women.
|OA=1
}}

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

{{PMID Auto
|PMID=20559687
|Title=CYP1A2 polymorphisms, occupational and environmental exposures and risk of bladder cancer.
}}

{{PMID Auto
|PMID=22466345
|Title=Joint effects of smoking and gene variants involved in sex steroid metabolism on hot flashes in late reproductive-age women.
|OA=1
}}

{{GET Evidence
|impact=pharmacogenetic
|qualified_impact=Insufficiently evaluated pharmacogenetic
|inheritance=unknown
|quality_scores=Array
|dbsnp_id=rs762551
|overall_frequency_n=76
|overall_frequency_d=128
|overall_frequency=0.59375
|n_genomes=45
|n_genomes_annotated=0
|n_haplomes=65
|n_articles=4
|n_articles_annotated=2
|in_pharmgkb=Y
|autoscore=1
|webscore=N
}}

{{PMID Auto
|PMID=23128882
|Title=Role of CYP1A2 polymorphisms in breast cancer risk in women
}}

{{PMID Auto
|PMID=23492908
|Title=Influence of CYP1A1/CYP1A2 and AHR polymorphisms on systemic olanzapine exposure
}}

{{PMID Auto
|PMID=23528250
|Title=Genetic association of aromatic hydrocarbon receptor (AHR) and cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) polymorphisms with dioxin blood concentrations among pregnant Japanese women
}}

{{PMID Auto
|PMID=23530639
|Title=High Coffee Intake, but Not Caffeine, is Associated with Reduced Estrogen Receptor Negative and Postmenopausal Breast Cancer Risk with No Effect Modification by CYP1A2 Genotype
}}

{{PMID Auto
|PMID=23686565
|Title=Genetic polymorphism of cytochrome P450 (CYP) 1A1, CYP1A2, and CYP2E1 genes modulate susceptibility to gastric cancer in patients with Helicobacter pylori infection
}}

{{PMID Auto
|PMID=23130019
|Title=Frequencies of 23 functionally significant variant alleles related with metabolism of antineoplastic drugs in the chilean population: comparison with caucasian and asian populations.
|OA=1
}}

{{PMID Auto
|PMID=23157985
|Title=CYP1A2 rs762551 polymorphism contributes to cancer susceptibility: a meta-analysis from 19 case-control studies.
|OA=1
}}

{{PMID Auto
|PMID=23175176
|Title=Variation in PAH-related DNA adduct levels among non-smokers: the role of multiple genetic polymorphisms and nucleotide excision repair phenotype.
}}

{{PMID Auto
|PMID=23462460
|Title=Current evidence on the relationship between three polymorphisms in the CYP1A2 gene and the risk of cancer.
}}

{{PMID Auto
|PMID=23628800
|Title=Role of CYP1A2 1F polymorphism in cancer risk: evidence from a meta-analysis of 46 case-control studies.
}}

{{PMID Auto
|PMID=25081684
|Title=Four Polymorphisms in the Cytochrome P450 1A2 (CYP1A2) Gene and Lung Cancer Risk: a Meta-analysis
}}
{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | Illumina Human 1M}}