VKORC1 Single Nucleotide Polymorphisms Research Articles

VKORC1 single nucleotide polymorphisms in rodents in Spain

Rodents are considered one of the animal pests with the greatest impact on agricultural production and public health. Anticoagulant rodenticides (ARs), used as one of the most effective ways to control rodent populations worldwide, inhibit the vitamin K 2,3-epoxide reductase (VKORC1) enzyme involved in blood coagulation. Resistances to ARs are mainly associated with mutations or single nucleotide polymorphisms (SNPs) in the vkorc1 gene. Since the information on this subject is scarce in Spain, we monitored and discovered rodent SNPs that could favour genetic resistance in its populations. For that, more than 200 samples of stools and tails from brown rat (Rattus norvegicus), black rat (Rattus rattus) and mouse (Mus musculus) were collected from 12 Spanish regions previously identified with low AR efficacy in coordination with the National Association of Environmental Sanitation Companies (ANECPLA) and the managing entities of four locations. We then sequenced their vkorc1 exon 3 corresponding genomic DNA. We identified genotypic vkorc1 variations corresponding to amino acid changes at the VKORC1 protein at the S149I – S149T and the E155K - E155Q mutations, depending on the rodent species. Computational analysis of binding predictions found out that the brown rat S149I mutation predicted a high reduction of the binding affinity of chlorophacinone and brodifacoum ARs while, the black rat S149T, E155K and E155Q mutations slightly reduced bromadiolone AR binding. These results suggest that these mutations may be one of the causes of the increased resistance to those ARs.

Genetic Associations With Stable Warfarin Dose Requirements in Han Chinese Patients.

Warfarin is a commonly prescribed anticoagulant for valvular heart disease that plays an important role in clinical management to prevent thrombotic events. In this study, we aim to perform a comprehensive study to investigate the genetic biomarkers of stable warfarin dose in the Han Chinese population. We performed an integrative study on 211 Han Chinese patients with valvular heart disease. A total of 40 single nucleotide polymorphisms (SNPs) in 10 important genes (CYP2C9, VKORC1, ABCB1, CYP4F2, APOE, PROC, GGCX, EPHX1, CALU, and SETD1A) which are involved in the warfarin metabolic pathway and equilibrium of coagulation and anticoagulation were selected. We applied MassARRAY technology to genotype the 40 SNPs identified in these Han Chinese patients. Our results showed that 13 SNPs on 6 genes (CYP2C9, VKORC1, ABCB1, PROC, EPHX1, and SETD1A) were associated with the individual stable warfarin dose. Two VKORC1 SNPs (rs9934438 and rs2359612) were the strongest genetic factors determining warfarin dose requirements (P = 8 × 10-6 and 9 × 10-6, respectively). Rs4889599 in SETD1A was first reported to be associated with warfarin dose at a significant level of 0.001 in our study (Padjust = 0.040 after Bonferroni correction). We discovered that genetic variants in CYP2C9, VKORC1, ABCB1, PROC, EPHX1, and SETD1A may affect the stable warfarin dose requirement in Han Chinese patients with valvular disease. The discovery of these potential genetic markers will facilitate the development of advanced personalized anticoagulation therapy in Han Chinese patients.

Prevalence of rs2108622 (CYP4F2*3) Single Nucleotide Polymorphism – A Review

Cardiovascular diseases are known to be treated with anticoagulants lifelong. Warfarin is one of the most commonly used medications for anticoagulation despite causing serious side effects in some patients. Different single nucleotide polymorphisms (SNPs) that have a role in the cytochrome P450 system can also affect the metabolism, as well as dosing, of warfarin. The purpose of this review is to look into the prevalence of this SNP in the past research and screen for possible correlations with age, place of origin, family history of cardiovascular and cerebrovascular diseases, or other medical conditions possibly present in various populations. In total, 20 scientific articles falling under the inclusion criteria were reviewed and found usable, and the rest of the cases will be highly beneficial in the upcoming years to determine the role of the recently discovered CYP4F2 rs2108622 variant, as well as the previously known CYP2C9 and VKORC1 SNPs, in the variance of warfarin dose requirement. These findings may also point researchers in the right direction for qualifying and validating these genetic variants for use as GBs (genomic biomarkers) in the clinical and medical practice of treatment with warfarin.

Impact of CYP2C9 and VKORC1 Polymorphisms on Warfarin Sensitivity and Responsiveness in Jordanian Cardiovascular Patients during the Initiation Therapy.

Warfarin is an oral anticoagulant frequently used in the treatment of different cardiovascular diseases. Genetic polymorphisms in the CYP2C9 and VKORC1 genes have produced variants with altered catalytic properties. A total of 212 cardiovascular patients were genotyped for 17 Single Nucleotide Polymorphisms (SNPs) within the CYP2C9 and VKORC1 genes. This study confirmed a genetic association of the CYP2C9*3 and VKORC1 rs10871454, rs8050894, rs9934438, and rs17708472 SNPs with warfarin sensitivity. This study also found an association between CYP2C9 and VKORC1 genetic haplotype blocks and warfarin sensitivity. The initial warfarin dose was significantly related to the CYP2C9*3 polymorphism and the four VKORC1 SNPs (p < 0.001). There were significant associations between rs4086116 SNP and TAT haplotype within CYP2C9 gene and rs17708472 SNP and CCGG haplotype within VKORC1 gene and warfarin responsiveness. However, possessing a VKORC1 variant allele was found to affect the international normalized ratio (INR) outcomes during initiation of warfarin therapy. In contrast, there was a loose association between the CYP2C9 variant and INR measurements. These findings can enhance the current understanding of the great variability in response to warfarin treatment in Arabs.

VKORC1-1639A allele influences warfarin maintenance dosage among Blacks receiving warfarin anticoagulation: a retrospective cohort study.

The study objectives were to investigate the association between selected CYP2C9 and VKORC1 single nucleotide polymorphisms with serious bleeding or thrombotic risk, and to estimate mean daily maintenance dose of warfarin and international normalized ratio measurements among Blacks receiving warfarin anticoagulation. We conducted a retrospective cohort study among 230 Black adults receiving warfarin for a minimum of three consecutive months with a confirmed date of first dosage. A lower mean daily maintenance dosage of warfarin was required to maintain an international normalized ratio measurement within the therapeutic range among Blacks with the VKORC1-1639G>A variant alleles ([G/A vs G/G, p=0.02], [A/A vs G/A, p=0.008] and [A/A vs G/G, p=0.001]). Data indicated that VKORC1-1639A variant allele influenced warfarin daily maintenance dosage among our small, likely admixed Black patient population.

Pharmacogenetic determinants of outcomes on triplet hepatic artery infusion and intravenous cetuximab for liver metastases from colorectal cancer (European trial OPTILIV, NCT00852228)

Background:The hepatic artery infusion (HAI) of irinotecan, oxaliplatin and 5-fluorouracil with intravenous cetuximab achieved outstanding efficacy in previously treated patients with initially unresectable liver metastases from colorectal cancer. This planned study aimed at the identification of pharmacogenetic predictors of outcomes.Methods:Circulating mononuclear cells were analysed for 207 single-nucleotide polymorphisms (SNPs) from 34 pharmacology genes. Single-nucleotide polymorphisms passing stringent Hardy–Weinberg equilibrium test were tested for their association with outcomes in 52 patients (male/female, 36/16; WHO PS, 0–1).Results:VKORC1 SNPs (rs9923231 and rs9934438) were associated with early and objective responses, and survival. For rs9923231, T/T achieved more early responses than C/T (50% vs 5%, P=0.029) and greatest 4-year survival (46% vs 0%, P=0.006). N-acetyltransferase-2 (rs1041983 and rs1801280) were associated with up to seven-fold more macroscopically complete hepatectomies. Progression-free survival was largest in ABCB1 rs1045642 T/T (P=0.026) and rs2032582 T/T (P=0.035). Associations were found between toxicities and gene variants (P<0.05), including neutropenia with ABCB1 (rs1045642) and SLC0B3 (rs4149117 and rs7311358); and diarrhoea with CYP2C9 (rs1057910), CYP2C19 (rs3758581), UGT1A6 (rs4124874) and SLC22A1 (rs72552763).Conclusion:VKORC1, NAT2 and ABCB1 variants predicted for HAI efficacy. Pharmacogenetics could guide the personalisation of liver-targeted medico-surgical therapies.

Vitamin K epoxide reductase complex subunit 1 (VKORC1): A pharmacogenomic predictor of response and survival in patients (pts) on triplet hepatic artery infusion (HAI) and intravenous cetuximab (IV-Cet) for initially unresectable liver metastases from colorectal cancer (uLM-CRC) (EU trial OPTILIV).

2569 Background: The HAI of Irinotecan-Oxaliplatin-5-Fluorouracil (IFO) with IV-Cet achieved 29.7% complete uLM-CRC resections (R0+R1) and an overall median survival (OS) of 25.7 months in previously treated pts (Lévi, Ann Oncol 2016). Methods: To identify pharmacogenomic predictors of outcomes, 207 single nucleotide polymorphisms (SNPs) from 34 pharmacology genes were analysed in blood mononuclear cells (ADME PGx, MassArray platform, Sequenom, USA). Relations between SNPs and tumor response, R0+R1, survival, and toxicities were tested using adjusted Mann Whitney, Fisher Exact, Log Rank tests and Hardy-Weinberg Equilibrium. Results: Pts (16F;36M; 33-76 yo; WHO performance status 0-1) received protocol treatment as 2nd (21 pts) or 3-4thline (31 pts). VKORC1 SNPs in promoter (rs9923231) and intron (rs9934438) were consistently associated with early and objective responses, and overall survival. For rs9923231, T/T (N = 8) as compared to C/T (N = 21) had greatest chance of achieving early response (50% vs 5%, p = 0.029) or 4-y survival (46% vs 0%, p = 0.006). VKORC1 SNPs also related to HA thrombosis (rs992331, T/T, 77% vs C/C, 30%, p = 0.04). In contrast, NAT2 SNPs (rs1041983 and rs1801280) were associated with up to 5-fold differences in R0-R1 resection rate. Statistically significant associations (p &lt; 0.05) of SNPs with clinical outcomes were found for oxydo-reduction (CYP2E1 and HA thrombosis; CYP2C9 and diarrhea; CYP2C19 and diarrhea, fatigue, and early response), conjugation (UGT1A1 and diarrhea; NAT2 and fatigue); and transport (ABCB1 or SLC0B3 and neutropenia; SLC22A1 and diarrhea; SLC 15A2 and early response). Conclusions: VKORC1 was highlighted for the first time, as a pharmacogenomic predictor of HAI efficacy for LM-CRC. Conversion-to-resection was associated with NAT2 polymorphism. VKORC1 γ-carboxylates vitamin K-dependent proteins. Its polymorphism guides personalized warfarin dosing. VKORC1 SNPs determination could help identify the uLM-CRC pts who best benefit from intensive HAI therapy. Clinical trial information: NCT00852228.

Association Between VKORC1 Gene Polymorphisms and Ischemic Cerebrovascular Disease in Chinese Han Population

The vitamin K epoxide reductase subunit 1 gene (VKORC1) plays a key role in vitamin K recycling, and there is a close association between VKORC1 gene single-nucleotide polymorphisms (SNPs) and the required dose of warfarin, an anticoagulant. However, the association between VKORC1 SNPs and ischemic cerebrovascular disease (ICVD) has not been defined. This case-control study involved 370 patients with ICVD and 408 healthy individuals (controls) from Chinese Han population. Two VKORC1 gene SNPs (1639A/G and 1173T/C) were genotyped by PCR-RFLP method. The G allele frequencies of the 1639A/G locus and C allele frequencies of the 1173T/C locus were higher in the ICVD group than in the control group (p = 0.014 and p = 0.008, respectively). Haplotype analysis showed that 1639G-1173C was associated with an increased risk of ICVD (odds ratio (OR) = 1.163, 95% confidence interval (CI) = 1.137~2.288), while 1639A-1173T was associated with decreased risk of ICVD (OR = 0.620, 95% CI = 0.437~0.880). Our findings suggested that individuals carrying the 1639G or 1173C allele might be at increased risk for ICVD. Furthermore, the 1639G-1173C haplotype was a risk factor for ICVD, and 1639A-1173T was a protective factor in Chinese Han population.

Population diversity and the performance of warfarin dosing algorithms.

Population diversity and the performance of warfarin dosing algorithms.

Distribution of CYP2C9 and VKORC1 Risk Alleles for Warfarin Sensitivity and Resistance in the Israeli Population

This study was designed to delineate the relative frequency of CYP2C9 and VKORC1 polymorphisms known to affect warfarin response in the highly heterogeneous Israeli population. Frequencies of CYP2C9 allelic variants CYP2C9*2, CYP2C9*3 and of VKORC1 single nucleotide polymorphisms (snps) -1639G>A and D36Y were determined in genomic DNA of 438 healthy unrelated Israeli volunteers of Jewish, Druze and Arab Moslem descent, using allele specific PCR-RFLP. Genotyping results obtained were confirmed by probe free High Resolution Melt (HRM) Technology. Arab Moslems had a higher frequency of warfarin "sensitive" CYP2C9*2, CYP2C9*3 and VKROC1 -1639G>A alleles (0.21, 0.07 and 0.58, respectively) than both Jews (0.13, 0.11 and 0.57, respectively) and Druze (0.12, 0.06 and 0.53, respectively). Statistically significant differences were found in CYP2C9*2 between Druze and Moslems (p=0.01) and between Jews and Moslems (p=0.016) and in CYP2C9*3 between Druze and Jews (p=0.0086). VKORC1(-1639G>A) was the major gene polymorphism associated with warfarin sensitivity in all 3 subpopulations. In contrast, the warfarin "resistant" VKORC1 D36Y allele was very rare in the Israeli population (0-0.015). The results presented demonstrate that allelic variants in CYP2C9 and VKORC1 are very common in Israel with approximately 95% of Jews, approximately 84% of Druze and approximately 91% of Arab Moslems manifesting at least one known warfarin "sensitive" or "resistant" allele. Individualized genotype based warfarin therapy is highly relevant in the Israeli population due to the high incidence of genetic variations associated with warfarin sensitivity in all 3 non-mixing subpopulations tested.

Warfarin pharmacogenetics: a single VKORC1 polymorphism is predictive of dose across 3 racial groups

AbstractWarfarin-dosing algorithms incorporating CYP2C9 and VKORC1 −1639G>A improve dose prediction compared with algorithms based solely on clinical and demographic factors. However, these algorithms better capture dose variability among whites than Asians or blacks. Herein, we evaluate whether other VKORC1 polymorphisms and haplotypes explain additional variation in warfarin dose beyond that explained by VKORC1 −1639G>A among Asians (n = 1103), blacks (n = 670), and whites (n = 3113). Participants were recruited from 11 countries as part of the International Warfarin Pharmacogenetics Consortium effort. Evaluation of the effects of individual VKORC1 single nucleotide polymorphisms (SNPs) and haplotypes on warfarin dose used both univariate and multi variable linear regression. VKORC1 −1639G>A and 1173C>T individually explained the greatest variance in dose in all 3 racial groups. Incorporation of additional VKORC1 SNPs or haplotypes did not further improve dose prediction. VKORC1 explained greater variability in dose among whites than blacks and Asians. Differences in the percentage of variance in dose explained by VKORC1 across race were largely accounted for by the frequency of the −1639A (or 1173T) allele. Thus, clinicians should recognize that, although at a population level, the contribution of VKORC1 toward dose requirements is higher in whites than in nonwhites; genotype predicts similar dose requirements across racial groups.

Polymorphisms in the VKORC1 gene are strongly associated with warfarin dosage requirements in patients receiving anticoagulation

Background: Warfarin is a mainstay of therapy for conditions associated with an increased risk of thromboembolic events. However, the use of this common agent is fraught with complications and little...