Important Haplotype Information for VKORC1

Citation: VKORC1 Pharmacogenomics Summary. Owen RP, Gong L, Sagreiya H, Klein TE, Altman RB. Pharmacogenet Genomics. 2009 Nov 24. Epub ahead of print. PMID:19940803

PharmGKB VIP Submitted by: Ryan Owen
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PharmGKB VIP Submission date: January 29th, 2007


There are Four Important Haplotypes for VKORC1.

  1. VKORC1*1
  2. VKORC1*2
  3. VKORC1*3
  4. VKORC1*4

1. VKORC1*1

Gene HGNC Name: VKORC1
Haplotype Name VKORC1*1
Does this haplotype span more than one gene?
Unknown
What is the definitive publication or website defining this haplotype?
VKORC1 haplotypes and their impact on the inter-individual and inter-ethnic variability of oral anticoagulation. Geisen et al [PMID: 16270629].
Haplotype Summary: This haplotype is the same as the reference sequence AY587020, and is considered to be the ancestral haplotype of VKORC1 [16270629]. VKORC1*1 seems to only occur at high frequencies in populations of African origin, but VKORC1*1 is not the most common haplotype in the African population reported by Geisen et al [16270629].
Key PubMed IDs: 16270629
How many SNPs, indels, or repeats define this haplotype?
The reference sequence: AY587020
Linked to Variant Worksheets?
No
Drugs/Substrates: Warfarin, coumarin, acenocoumarol
Key Phenotypes/Diseases: Atrial Fibrillation, Coagulation Protein Disorders, Hemorrhage, Vascular Diseases
Phenotype Datasets
WUSTL warfarin doing data, group A

2. VKORC1*2

Gene HGNC Name: VKORC1
Haplotype Name VKORC1*2, H1 and H2, Haplotype group A
Does this haplotype span more than one gene? Unknown
What is the definitive publication or website defining this haplotype? VKORC1 haplotypes and their impact on the inter-individual and inter-ethnic variability of oral anticoagulation. Geisen et al [PMID: 16270629].
Effect of VKORC1 haplotypes on transcriptional regulation and warfarin dose. Reider et al [PMID: 15930419].
Haplotype Summary: VKORC1*2, or H1 and H2, or haplotype group A of VKORC1 all represent the haplotype that is associated with response to a lower dose of warfarin. There are subtle differences in the definitions of these haplotypes, but all contain an A allele at position 3673 and a T allele at position 6484 of AY587020. VKORC1*2 was defined by Geisen et al [16270629], and H1 and H2 (haplotype group A) were defined by Reider et al [15930419]. VKORC1*2 is the predominant haplotype in the Asian population, and it is also quite common among Caucasians. This haplotype also exists in African populations, but it is less frequent [16270629].
Key PubMed IDs: 15930419 16270629
How many SNPs, indels, or repeats define this haplotype? VKORC1*2 (4), H1 (5), H2 (6), haplotype group A includes both H1 and H2.
Linked to Variant Worksheets? G3673A, C6484T
Drugs/Substrates: Warfarin, coumarin, acenocoumarol
Key Phenotypes/Diseases: Atrial Fibrillation, Coagulation Protein Disorders, Hemorrhage, Vascular Diseases
Phenotype Datasets: WUSTL warfarin dosing data, group A

3. VKORC1*3

Gene HGNC Name: VKORC1
Haplotype Name VKORC1*3
Does this haplotype span more than one gene? Unknown
What is the definitive publication or website defining this haplotype? VKORC1 haplotypes and their impact on the inter-individual and inter-ethnic variability of oral anticoagulation. Geisen et al [PMID: 16270629].
Effect of VKORC1 haplotypes on transcriptional regulation and warfarin dose. Reider et al [PMID: 15930419].
Haplotype Summary: Most of the VKORC1 haplotype literature uses either the terminology of Reider et al [15930419] or Geisen et al [16270629] when describing VKORC1 haplotypes, but this can get confusing when attempting to delineate between VKORC1*3 and VKORC1*4. In the analysis of Reider et al, both VKORC1*3 and VKORC1*4 are included in haplotype group B. Again, although there are subtle differences, the H7 and H8 groups of Reider approximately correspond to the VKORC1*3 group of Geisen et al, whereas H9 of Reider (also in haplotype group B) corresponds more closely with VKORC1*4 as defined by Geisen.
The key SNP for the differentiating between VKORC1*3 and VKORC1*4 is the allele at position 9041 [16270629]. D'Andrea et al found a trend towards increased warfarin dose requirements for patients homozygous for the A allele at position 9041 versus patients who were either heterozygous or homozygous for the G allele [15358623], and Herman et al also found that the allele at position 9041 influenced warfarin dosing requirements 16676068.
VKORC1*3 is the most common haplotype in the African population, and is also very common among Caucasians (similar to the frequency of VKORC1*2 in Caucasian populations).
Key PubMed IDs: 15930419 16270629 15358623 16676068
How many SNPs, indels, or repeats define this haplotype? VKORC1*3 (1), H7 (1), H8 (2), haplotype group B contains H7, H8, and H9
Linked to Variant Worksheets? G9041A
Drugs/Substrates: Warfarin, coumarin, acenocoumarol
Phenotypes/Diseases: Atrial Fibrillation, Coagulation Protein Disorders, Hemorrhage, Vascular Diseases
Phenotype Datasets: WUSTL warfarin dosing data, group A

4. VKORC1*4

Gene HGNC Name: VKORC1
Haplotype Name VKORC1*4
Does this haplotype span more than one gene? Unknown
What is the definitive publication or website defining this haplotype? VKORC1 haplotypes and their impact on the inter-individual and inter-ethnic variability of oral anticoagulation. Geisen et al [PMID: 16270629].
Effect of VKORC1 haplotypes on transcriptional regulation and warfarin dose. Reider et al [PMID: 15930419]
Haplotype Summary: VKORC1*4 is similar to VKORC1*3 but it contains the reference allele at position 9041 [16270629]. In the analysis of Rieder et al, VKORC1*4 was included in haplotype group B, and thus was associated with a higher dose of warfarin [15930419 16676068]. However, some groups have shown that the allele at position 9041 may itself be predictive of a high warfarin dose phenotype [15358623 16676068], and this would potentially distinguish VKORC1*3 from VKORC1*4 as the "high dose" haplotype.
Key PubMed IDs: 16270629 15930419 16676068 15358623
How many SNPs, indels, or repeats define this haplotype? VKORC1*4 (1), H9 (3), haplotype group B contains H7, H8, and H9
Linked to Variant Worksheets? No
Drugs/Substrates: Warfarin, coumarin, acenocoumarol
Phenotypes/Diseases: Atrial Fibrillation, Coagulation Protein Disorders, Hemorrhage, Vascular Diseases
Phenotype Datasets:
WUSTL warfarin dosing data, group A
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