A novel functional VKORC1 promoter polymorphism is associated with inter-individual and inter-ethnic differences in warfarin sensitivity

Hum Mol Genet. 2005 Jul 1;14(13):1745-51. doi: 10.1093/hmg/ddi180. Epub 2005 May 11.


Warfarin, a commonly prescribed anticoagulant, exhibited large inter-individual and inter-ethnic differences in the dose required for its anticoagulation effect. Asian populations, including Chinese, require a much lower maintenance dose than Caucasians, for which the mechanisms still remain unknown. We determined DNA sequence variants in CYP2C9 and VKORC1 in 16 Chinese patients having warfarin sensitivity (< or = 1.5 mg/day, n = 11) or resistance (> or = 6.0 mg/day, n = 5), 104 randomly selected Chinese patients receiving warfarin, 95 normal Chinese controls and 92 normal Caucasians. We identified three CYP2C9 variants, CYP2C9*3, T299A and P382L, in four warfarin-sensitive patients. A novel VKORC1 promoter polymorphism (-1639 G > A) presented in the homozygous form (genotype AA) was found in all warfarin-sensitive patients. The resistant patients were either AG or GG. Among the 104 randomly selected Chinese patients receiving warfarin, AA genotype also had lower dose than the AG/GG genotype (P < 0.0001). Frequencies of AA, AG and GG genotypes were comparable in Chinese patients receiving warfarin (79.7, 17.6 and 2.7%) and normal Chinese controls (82, 18 and 0%), but differed significantly from Caucasians (14, 47 and 39%) (P < 0.0001). The promoter polymorphism abolished the E-box consensus sequences and dual luciferase assay revealed that VOKRC1 promoter with the G allele had a 44% increase of activity when compared with the A allele. The differences in allele frequencies of A/G allele and its levels of VKORC1 promoter activity may underscore the inter-individual differences in warfarin dosage as well as inter-ethnic differences between Chinese and Caucasians.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anticoagulants / administration & dosage*
  • Aryl Hydrocarbon Hydroxylases / genetics
  • Asian People
  • Cardiovascular Diseases / drug therapy
  • Cardiovascular Diseases / genetics
  • Cytochrome P-450 CYP2C9
  • Drug Resistance / genetics*
  • Female
  • Gene Frequency / genetics
  • Genotype
  • Humans
  • Male
  • Middle Aged
  • Mixed Function Oxygenases / genetics*
  • Polymorphism, Single Nucleotide / genetics*
  • Promoter Regions, Genetic / genetics*
  • Vitamin K Epoxide Reductases
  • Warfarin / administration & dosage*
  • White People


  • Anticoagulants
  • Warfarin
  • Mixed Function Oxygenases
  • CYP2C9 protein, human
  • Cytochrome P-450 CYP2C9
  • Aryl Hydrocarbon Hydroxylases
  • VKORC1 protein, human
  • Vitamin K Epoxide Reductases