PharmacogenomicsEvidence 1A

rs9923231 · VKORC1

Risk allele: T

Risk-Allele Phenotype

VKORC1 -1639G>A promoter variant; reduced VKORC1 expression; increased warfarin sensitivity with 20-30% lower stable dose required; higher bleeding risk if dosed as wild-type.

Reference-Allele Phenotype

Normal VKORC1 expression and warfarin requirement.

Evidence Level

1A — Strong — multiple high-quality studies See methodology for how we grade evidence.

Cross-References

dbSNP — rs9923231
ClinVar — search rs9923231
NCBI Gene — VKORC1
PharmGKB — rs9923231

Informational only

This page summarizes population-level evidence about a genetic variant. It is not a diagnosis. Your individual risk depends on your full genome, lifestyle, environment, and family history. Consult a healthcare provider for personalized medical advice.

Want to know your status at rs9923231?

Upload your DNA file — Atlagene checks this variant and 700+ others across 21 health categories.

Get Started Free