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Gene

CYP2C9

cytochrome P450 family 2 subfamily C member 9

Summary

Cytogenetic location
10q23.33
Coordinates
Chromosome 10: 94,938,658–94,990,091 (GRCh38)
Exons
9 exons across 51.4 kb
Protein
490 amino acids
Also known as
P450IIC9
Previous symbols
CYP2C10
MANE Select transcript
ENST00000260682.8NM_000771.4
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

CYP2C9 and medicines

  • Warfarin & NSAID metabolism

    Pharmacogenomics

    CYP2C9 clears warfarin, phenytoin, and many NSAIDs — including celecoxib, ibuprofen, meloxicam and piroxicam. Reduced-function alleles slow that clearance, lowering the warfarin dose you need and raising exposure to the others.

    • If you are ever started on warfarin, genotype-guided dosing (CYP2C9 + VKORC1 + CYP4F2) can shorten the time to a stable dose.
    • For NSAIDs such as celecoxib, ibuprofen, flurbiprofen, meloxicam and piroxicam, poor metabolisers may need a lower dose or an alternative — especially for long-term use.
    • Relevant to the anti-seizure drugs phenytoin and fosphenytoin, where reduced activity raises the risk of toxicity.
    • Siponimod, a multiple sclerosis treatment, requires CYP2C9 genotyping before it is prescribed and is not used in people with two copies of *3.

    Alleles the report reads

    • *3No function
    • *6No function
    • *5Decreased function
    • *11Decreased function
    • *1Normal function
    • *2Decreased function
    • *8Decreased function

    Results CPIC describes

    • Poor Metabolizer
    • Indeterminate
    • Normal Metabolizer
    • Intermediate Metabolizer
    MedicineCPIC levelGuideline
    celecoxibACYP2C9 and NSAIDs
    flurbiprofenACYP2C9 and NSAIDs
    fluvastatinASLCO1B1, ABCG2, CYP2C9, and Statins
    fosphenytoinACYP2C9, HLA-B and Phenytoin
    ibuprofenACYP2C9 and NSAIDs
    lornoxicamACYP2C9 and NSAIDs
    meloxicamACYP2C9 and NSAIDs
    phenytoinACYP2C9, HLA-B and Phenytoin
    piroxicamACYP2C9 and NSAIDs
    siponimodA
    tenoxicamACYP2C9 and NSAIDs
    warfarinACYP2C9, VKORC1, CYP4F2 and Warfarin
    acenocoumarolB
    Show 12 more medicines
    MedicineCPIC levelGuideline
    avatrombopagB/C
    dronabinolB/C
    erdafitinibB/C
    lesinuradB/C
    aceclofenacCCYP2C9 and NSAIDs
    aspirinCCYP2C9 and NSAIDs
    diclofenacCCYP2C9 and NSAIDs
    flibanserinC
    indomethacinCCYP2C9 and NSAIDs
    lumiracoxibCCYP2C9 and NSAIDs
    nabumetoneCCYP2C9 and NSAIDs
    naproxenCCYP2C9 and NSAIDs

    Calls *2 and *3 plus the *5, *6, *8 and *11 alleles that matter most in African-ancestry populations. The CYP2C-cluster variant rs12777823, which also informs warfarin dosing in that group, is not assessed here.

How CYP2C9 is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Stretches short reads find hard
Chromosome 10, with a bracket where CYP2C9 sits. CYP2C9 and 9 genes near it on chromosome 10, from 94,464,375 to 95,464,374.Chromosome 1010q23.33p15.3p15.2p15.1p14p13p12.33p12.32p12.31p12.2p12.1p11.23p11.22p11.21p11.1q11.1q11.21q11.22q11.23q21.1q21.2q21.3q22.1q22.2q22.3q23.1q23.2q23.31q23.32q23.33q24.1q24.2q24.31q24.32q24.33q25.1q25.2q25.3q26.11q26.12q26.13q26.2q26.394.6 Mb94.8 Mb95 Mb95.2 Mb95.4 MbTBC1D12: 94,402,377–94,537,452, forward strandTBC1D12HELLS: 94,545,329–94,613,905, forward strandHELLSCYP2C18: 94,682,860–94,736,241, forward strandCYP2C18: 94,688,154–94,853,073, forward strandCYP2C19: 94,762,536–94,922,264, forward strandCYP2C19CYP2C9: 94,938,658–94,990,091, forward strandCYP2C9CYP2C8: 95,034,359–95,069,603, reverse strandCYP2C8ACSM6: 95,194,200–95,228,929, forward strandACSM6PDLIM1: 95,237,569–95,291,126, reverse strandPDLIM1SORBS1: 95,311,390–95,561,469, reverse strandSORBS1Diagram of CYP2C9: 9 exons on the forward strand of chromosome 10Exon 1: 94,938,658–94,938,850, 193 basesExon 2: 94,941,858–94,942,020, 163 basesExon 3: 94,942,192–94,942,341, 150 basesExon 4: 94,947,779–94,947,939, 161 basesExon 5: 94,949,108–94,949,284, 177 basesExon 6: 94,972,104–94,972,245, 142 basesExon 7: 94,981,183–94,981,370, 188 basesExon 8: 94,986,033–94,986,174, 142 basesExon 9: 94,988,847–94,990,091, 1,245 bases1246895′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 2.6 kb of the gene's 51.4 kb; 1,473 of those bases code for the protein.

Traits linked to CYP2C9

The Human Phenotype Ontology lists these as features of the rare conditions CYP2C9 can cause. Each trait's page lists the other genes linked to it.

External links

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • CPIC and PharmGKB: the alleles, results and medicines.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.

Cite this page

APA

Dante Labs. (n.d.). CYP2C9 gene: cytochrome P450 family 2 subfamily C member 9. Retrieved 17 October 2026, from https://dantelabs.com/genes/cyp2c9

Vancouver

Dante Labs. CYP2C9 gene: cytochrome P450 family 2 subfamily C member 9 [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/cyp2c9

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