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Targeted next-generation sequencing of genes involved in Warfarin Pharmacodynamics and pharmacokinetics pathways using the Saudi Warfarin Pharmacogenetic study (SWAP). THE PHARMACOGENOMICS JOURNAL 2023:10.1038/s41397-023-00300-3. [PMID: 36739459 DOI: 10.1038/s41397-023-00300-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 01/15/2023] [Accepted: 01/26/2023] [Indexed: 02/06/2023]
Abstract
BACKGROUND Warfarin is an oral anticoagulant commonly used for treatment and prophylaxis against thromboembolic events. Warfarins's narrow therapeutic index window is one of the main challenges in clinical practice; thus, it requires frequent monitoring and dose adjustment to maintain patients' therapeutic range. Warfarin dose variation and response are attributed to several inter-and intra-individuals factors, including genetic variants in enzymes involved in warfarin pharmacokinetics (PK) and pharmacodynamics (PD) pathways. Thus, we aim to utilize the next-generation sequencing (NGS) approach to identify rare and common genetic variants that might be associated with warfarin responsiveness. METHOD AND RESULTS A predesigned NGS panel that included 16 genes involved in Warfarin PK/PD pathways was used to sequence 786 patients from the Saudi Warfarin Pharmacogenetic Cohort (SWAP). Identified variants were annotated using several annotation tools to identify the pathogenicity and allele frequencies of these variants. We conducted variants-level association tests with warfarin dose. We identified 710 variants within the sequenced genes; 19% were novel variants, with the vast majority being scarce variants. The genetic association tests showed that VKORC1 (rs9923231, and rs61742245), CYP2C9 (rs98332238, rs9332172, rs1057910, rs9332230, rs1799853, rs1057911, and rs9332119), CYP2C19 (rs28399511, and rs3758581), and CYP2C8 (rs11572080 and rs10509681) were significantly associated with warfarin weekly dose. Our model included genetics, and non-genetic factors explained 40.1% of warfarin dose variation. CONCLUSION The study identifies novel variants associated with warfarin dose in the Saudi population. These variants are more likely to be population-specific variants, suggesting that population-specific studies should be conducted before adopting a universal warfarin genotype-guided dosing algorithm.
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Koshy L, Vb R, M M, Ben MP, Kishor P, Sudhakaran PR, Abdullakutty J, Venugopal K, Zachariah G, Mohanan PP, Harikrishnan S, G S. Pharmacogenetic variants influence vitamin K anticoagulant dosing in patients with mechanical prosthetic heart valves. Pharmacogenomics 2022; 23:475-485. [PMID: 35608144 DOI: 10.2217/pgs-2022-0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background: Vitamin K antagonists (VKAs) are class I oral anticoagulants that are widely prescribed following surgical heart valve implantation. The objective of this study was to quantify the relative effects of VKORC1, CYP2C9 and CYP4F2 genotypes in predicting VKA dosing. Materials & methods: A total of 506 South Indian patients with mechanical prosthetic heart valves who were prescribed oral VKAs, such as warfarin or acenocoumarol, were genotyped. The discriminatory ability of mutant genotypes to predict dose categories and bleeding events was assessed using regression analysis. Results: The VKORC1 rs9923231, CYP2C9*3 and CYP4F2*3 mutant genotypes significantly influenced VKA-dose requirements and explained 27.47% of the observed dose variation. Conclusion: These results support pharmacogenetic screening for initial VKA dosing among South Indian patients with mechanical prosthetic heart valves.
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Affiliation(s)
- Linda Koshy
- Centre for Advanced Research & Excellence in Heart Failure, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, 695011, India
| | - Raghu Vb
- Inter-University Centre for Genomics & Gene Technology, Department of Biotechnology, University of Kerala, Trivandrum, Kerala, 695581, India
| | - Madhuma M
- Centre for Advanced Research & Excellence in Heart Failure, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, 695011, India
| | - Midhuna P Ben
- Inter-University Centre for Genomics & Gene Technology, Department of Biotechnology, University of Kerala, Trivandrum, Kerala, 695581, India
| | - Pritam Kishor
- Integrated Science Education & Research Centre, Visva-Bharati, Santineketan, West Bengal, 731235, India
| | - P R Sudhakaran
- Inter-University Centre for Genomics & Gene Technology, Department of Biotechnology, University of Kerala, Trivandrum, Kerala, 695581, India
| | | | - K Venugopal
- Department of Cardiology, Pushpagiri Hospital, Thiruvalla, Pathanamthitta, Kerala, 689101, India
| | - Geevar Zachariah
- Department of Cardiology, Mother Hospital, Thrissur, Kerala, 680012, India
| | - P P Mohanan
- Department of Cardiology, Westfort Hi-Tech Hospital, Thrissur, Kerala, 680002, India
| | - S Harikrishnan
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, 695011, India
| | - Sanjay G
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, 695011, India
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Harikrishnan S, Koshy L, Subramanian R, Sanjay G, Vineeth CP, Nair AJ, Nair GM, Sudhakaran PR. Value of VKORC1 (-1639G>A) rs9923231 genotyping in predicting warfarin dose: A replication study in South Indian population. Indian Heart J 2018; 70 Suppl 3:S110-S115. [PMID: 30595241 PMCID: PMC6310074 DOI: 10.1016/j.ihj.2018.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 06/25/2018] [Accepted: 07/09/2018] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Warfarin is the most commonly prescribed oral anticoagulant, although having a narrow therapeutic index and wide interindividual variability. The aim of this study was to replicate the utility of VKORC1 (-1639G>A) rs9923231 genotyping in predicting the mean daily dose and to evaluate its ability to categorize warfarin-treated patients to high-, intermediate-, or low-dose categories in the South Indian population. MATERIALS AND METHODS A cohort of 222 warfarin-treated patients was genotyped using restriction fragment length polymorphism method. The influence of the rs9923231 polymorphism on the variations in the mean daily dose was compared using one-way analysis of variance and linear regression analysis. Discriminatory ability of the rs9923231 polymorphism to group the patients into ordered dose categories was assessed by estimating the proportional odds ratios using the ordered logit regression analysis. RESULTS The frequency of AA genotype and A allele in the study sample was found to be 1.8% and 9.23%, respectively, which was similar to reports from other South Indian populations. The mean daily dose required to achieve the optimum international normalized ratio was significantly lower in AA homozygous genotype carriers (3.99 ± 1.67 mg/day) and GA heterozygous (4.26 ± 1.57 mg/day) compared to the GG genotype carriers (5.51 ± 2.13 mg/day), p = 0.003. The A allele carriers (GA+AA genotypes) had a 3.23 higher odds of being grouped as a low-dose requiring category compared to non-carriers (95% CI 1.49-6.98, p = 0.003). CONCLUSIONS These preliminary results strongly support the use of VKORC1 (-1639G>A) rs9923231 polymorphism for genetically guided initial warfarin dosing in South Indian patients with heart valve replacements.
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Affiliation(s)
- S Harikrishnan
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695 011, Kerala, India.
| | - Linda Koshy
- Inter-University Centre for Genomics and Gene Technology, Department of Biotechnology, University of Kerala, Trivandrum, 695 581, Kerala, India.
| | - Ram Subramanian
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695 011, Kerala, India.
| | - G Sanjay
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695 011, Kerala, India.
| | - C P Vineeth
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695 011, Kerala, India.
| | - A Jayakumaran Nair
- Inter-University Centre for Genomics and Gene Technology, Department of Biotechnology, University of Kerala, Trivandrum, 695 581, Kerala, India.
| | - G M Nair
- Inter-University Centre for Genomics and Gene Technology, Department of Biotechnology, University of Kerala, Trivandrum, 695 581, Kerala, India.
| | - P R Sudhakaran
- Inter-University Centre for Genomics and Gene Technology, Department of Biotechnology, University of Kerala, Trivandrum, 695 581, Kerala, India.
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Novel isomeric metabolite profiles correlate with warfarin metabolism phenotype during maintenance dosing in a pilot study of 29 patients. Blood Coagul Fibrinolysis 2018; 29:602-612. [PMID: 30334816 DOI: 10.1097/mbc.0000000000000752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
: For this pilot study, we leveraged metabolite patterns for warfarin patients to more accurately assess clinically relevant differences in drug metabolism. We tested our hypothesis that plasma metabolite levels correlate with the influence of clinical factors on R-warfarin and S-warfarin metabolism (warfarin metabolic phenotype). We recruited 29 patients receiving a maintenance dose and testing within targeted therapeutic range. We determined their CYP2C9 and vitamin K epoxide reductase genotype and profiled 14 isomeric forms of warfarin and its metabolites. We employed three novel types of clearance ratios using analyte levels to perform multiple-linear regression analyses with clinical factors impacting drug metabolism and dose-responses. Competitive clearance ratios correlated with seven clinical factors including lifestyle choices (smoking), genetics (CYP2C9 and vitamin K epoxide reductase 1), and drug interactions (omeprazole) along with age, weight, and malignancy. Significant competitive clearance ratio correlations (P = 0.04 to < 0.001) explained 21-95% variability. Their performances surpassed that of oxidative and metabolic clearance ratios based on the number and significance of correlations. Competitive clearance ratios may accurately assess significance of factors on maintaining levels of pharmacologically active forms of the drug and metabolites related to dose-responses and thus provide a strategy to minimize adverse events and improve safety during anticoagulant therapy. This unique capacity could provide a strategy in a future, higher power study with a larger cohort of patients to more accurately assess the significance of clinical factors on active drug levels contributing to warfarin dose-responses.
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Wasniewski S, Consuegra-Sánchez L, Conesa-Zamora P, García de Guadiana-Romualdo L, Ramos-Ruiz P, Merelo-Nicolás M, Clavel-Ruipérez FG, Alburquerque-González B, Soria-Arcos F, Castillo-Moreno JA. Low Performance of a Clinical-Genetic Model in the Estimation of Time in Therapeutic Range in Acenocoumarol-Adherent Patients with Nonvalvular Atrial Fibrillation: The Quality of Anticoagulation Challenge. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8012747. [PMID: 30417015 PMCID: PMC6207892 DOI: 10.1155/2018/8012747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/01/2018] [Accepted: 09/20/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND Anticoagulation with vitamin K antagonists continues to be a challenging task given the difficulty of achieving a correct time in therapeutic range (TTR). The SAMeTT2R2 score has been proposed to identify patients that will be good responders. In this study we aimed to analyse clinical and genetic factors involved in a correct level of anticoagulation in patients with atrial fibrillation and thereby potentially improve the diagnostic performance of SAMeTT2R2 score. METHODS We prospectively included 212 consecutive patients with nonvalvular atrial fibrillation under treatment with acenocoumarol for at least 6 months that were attended in a cardiology outpatient clinic and were categorized as adherent to medication. We carried out a multivariate regression analysis to detect the independent predictive factors of good control. In all patients VKORC1, CYP2C9⁎2, CYP2C9⁎3, and MIR133A2 genotyping was performed. RESULTS A total of 128 (60.4%) patients presented TTR <70% (average TTR = 63.2). We identified body mass index (OR 0.94, 95%CI 0.89-0.99, p=0.032) and regular vitamin K intake (OR 0.53, 95%CI 0.28-0.99, p= 0.046) as independent predictors of poor anticoagulation control. The discriminatory power of a clinical-genetic model derived from our cohort was significantly better compared to the SAMeTT2R2 score (C-statistic 0.658 versus 0.524, p<0.001). CONCLUSIONS In our study the SAMeTT2R2 score revealed a poor ability in the prediction of TTR. Besides SAMeTT2R2, body mass index and possibly vitamin K intake should be taken into account when deciding the optimal anticoagulation strategy. The information provided by the identified genotypes was marginal.
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Affiliation(s)
- Samantha Wasniewski
- Department of Cardiology, Santa Lucía General University Hospital, Cartagena-Murcia, Spain
| | | | - Pablo Conesa-Zamora
- Department of Clinical Analysis, Santa Lucía General University Hospital, Cartagena-Murcia, Spain
| | | | - Pablo Ramos-Ruiz
- Department of Cardiology, Santa Lucía General University Hospital, Cartagena-Murcia, Spain
| | - Marta Merelo-Nicolás
- Department of Cardiology, Santa Lucía General University Hospital, Cartagena-Murcia, Spain
| | | | | | - Federico Soria-Arcos
- Department of Cardiology, Santa Lucía General University Hospital, Cartagena-Murcia, Spain
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Ragia G, Karantza IM, Kelli-Kota E, Kolovou V, Kolovou G, Konstantinides S, Maltezos E, Tavridou A, Tziakas D, Maitland-van der Zee AH, Manolopoulos VG. Role of CYP4F2, CYP2C19, and CYP1A2 polymorphisms on acenocoumarol pharmacogenomic algorithm accuracy improvement in the Greek population: need for sub-phenotype analysis. Drug Metab Pers Ther 2017; 32:183-190. [PMID: 29252193 DOI: 10.1515/dmpt-2017-0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/15/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND We have earlier developed a pharmacogenomic algorithm for acenocoumarol dose prediction in Greek patients that included CYP2C9/VKORC1 genetic information. This study aims at analyzing the potential effect of CYP4F2, CYP2C19, and CYP1A2 gene polymorphisms on acenocoumarol dose requirements and at further improving the Greek-specific pharmacogenomic algorithm. METHODS A total of 205 Greek patients taking acenocoumarol (140 who reached and 65 who did not reach stable dose), participants of acenocoumarol EU-PACT trial, were included in the study. CYP4F2, CYP2C19, and CYP1A2 polymorphisms were genotyped by use of the PCR-RFLP method. All patients were previously genotyped for CYP2C9/VKORC1 polymorphisms. RESULTS In the pooled sample, CYP4F2, CYP2C19, and CYP1A2 polymorphisms do not affect independently acenocoumarol dose requirements. For CYP4F2, significant effects were found on patients' ability to reach stable dose and on acenocoumarol dose requirements when CYP2C9/VKORC1 sub-phenotypes were analyzed. Specifically, when the patients were stratified according to their CYP2C9/VKORC1 functional bins, in sensitive responders, CYP4F2*3 allele carriers (CYP4F2 *1/*3 and *3/*3 genotypes) were more frequent in the patient group who reached stable dose (p=0.049). Additionally, in CYP2C9 intermediate metabolizers (IMs), after adjusting for age, weight, and VKORC1 genotypes, CYP4F2 genotypes were significantly associated with acenocoumarol stable dose (β: 0.07; 95% CI: 0.006-0.134; p=0.033). CONCLUSIONS CYP4F2 gene shows a prominent weak association with acenocoumarol dose requirements. Sub-phenotype analysis is potentially important in determining additional gene polymorphisms that are associated with acenocoumarol dose requirements.
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Affiliation(s)
- Georgia Ragia
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Dragana Campus, 68100 Alexandroupolis, Greece, Phone: +30 2551 030523, Fax: +30 2551 030523; and DNALEX S.A., Alexandroupolis, Greece
| | - Ioanna-Maria Karantza
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Eleni Kelli-Kota
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Vana Kolovou
- Cardiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Genovefa Kolovou
- Cardiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Stavros Konstantinides
- University Cardiology Department, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Efstratios Maltezos
- Second Department of Internal Medicine, Democritus University of Thrace, Alexandroupolis, Greece
| | - Anna Tavridou
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Dimitrios Tziakas
- University Cardiology Department, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Anke H Maitland-van der Zee
- Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands
| | - Vangelis G Manolopoulos
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
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Chen P, Sun YQ, Yang GP, Li R, Pan J, Zhou YS. Influence of the CYP4F2 polymorphism on the risk of hemorrhagic complications in coumarin-treated patients. Saudi Med J 2016; 37:361-8. [PMID: 27052278 PMCID: PMC4852013 DOI: 10.15537/smj.2016.4.14036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Objectives: To evaluate the impact of the CYP4F2 polymorphism on bleeding complications and over-anticoagulation due to coumarin. Methods: A comprehensive literature search was performed to look for eligible studies published prior to February 2015 in EMBASE and PubMed. References were strictly identified by inclusion and exclusion criteria, and authors of primary studies were consulted for additional information and data. Revman 5.3 software was used to analyze the impact of the CYP4F2 polymorphism on hemorrhagic complications and over-anticoagulation events (international normalized ratio >4). Results: Eight studies involving 3,101 samples met the specified inclusion criteria. Compared with wild-type homozygotes (CYP4F2*1*1), carriers of the CYP4F2*3 variant had no significant effects on total bleeding events (odds ratio [OR]: 0.86; 95% confidence interval [CI]: 0.71-1.05; p=0.15), major hemorrhage complications in coumarin users (OR: 0.80; 95% CI: 0.64-1.01; p=0.06). Patients carried CYP4F2*3 also had nonsignificant associations with the risk of over-anticoagulation (relative risk [RR]: 079; 95% CI: 0.59-1.06; p=0.12). We found a lower risk in patients with homozygotes for CYP4F2*3, but there was no statistical significance (RR: 0.66; 95% CI: 0.43-1.01; p=0.05). Conclusion: This meta-analysis indicated the impact of the CYP4F2 polymorphism on bleeding complications and over-anticoagulation in coumarin-treated patients failed to reach the level of statistical significance. However, large-scale and well designed studies are necessary to determine conclusively the association between the CYP4F2 polymorphism and hemorrhage risk.
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Affiliation(s)
- Peng Chen
- Institute of Pharmacy & Pharmacology, University of South China, Hengyang, Hunan, China. E-mail.
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Shendre A, Brown TM, Liu N, Hill CE, Beasley TM, Nickerson DA, Limdi NA. Race-Specific Influence of CYP4F2 on Dose and Risk of Hemorrhage Among Warfarin Users. Pharmacotherapy 2016; 36:263-72. [PMID: 26877068 DOI: 10.1002/phar.1717] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE The p.V433M in cytochrome P450 4F2 (rs2108622, CYP4F2*3) is associated with a higher warfarin dose and lower risk of hemorrhage among European Americans. We evaluate the influence of CYP4F2*3 on warfarin dose, time to target international normalized ratio (INR), and stable dose, proportion of time spent in target range (PTTR), as well as the risk of overanticoagulation and hemorrhage among European and African Americans. DESIGN CYP4F2*3 was genotyped in 1238 patients initiated on warfarin in a prospective inception cohort. Multivariable linear regression was used to assess warfarin dose and PTTR; proportional hazards analysis was performed to evaluate time to target INR and stable dose, overanticoagulation, and hemorrhage. SETTING Two outpatient anticoagulation clinics. PARTICIPANTS A total of 1238 anticoagulated patients. OUTCOMES Warfarin dose (mg/day), time to target INR and stable dose, PTTR, overanticoagulation (INR more than 4), and major hemorrhage. RESULTS Minor allele frequency for the CYP4F2*3 variant was 30.3% among European Americans and 8.4% among African Americans. CYP4F2*3 was associated with higher dose among European Americans but not African Americans. Compared to CYP4F2*1/*1, *1/*3 was associated with a statistically nonsignificant increase in dose (4.5%, p=0.22) and *3/*3 was associated with a statistically significant increase in dose (13.2%, p=0.02). CYP4F2 genotype did not influence time to target INR, time to stable dose, or PTTR in either race group. CYP4F2*3/*3 was associated with a 31% lower risk of over anticoagulation (p=0.06). Incidence of hemorrhage was lower among participants with CYP4F2 *3/*3 compared with *1/*3 or *1/*1 (incidence rate ratio = 0.45, 95% confidence interval 0.14-1.11, p=0.09). After controlling for covariates, CYP4F2 *3/*3 was associated with a 52% lower risk of hemorrhage, although this was not statistically significant (p=0.24). CONCLUSION Possession of CYP4F2*3 variant influences warfarin dose among European Americans but not African Americans. The CYP4F2-dose, CYP4F2-overanticoagulation, and CYP4F2-hemorrhage association follows a recessive pattern with possession of CYP4F2*3/*3 genotype likely demonstrating a protective effect. These findings need further confirmation.
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Affiliation(s)
- Aditi Shendre
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Todd M Brown
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Nianjun Liu
- Biostatistics, Section on Statistical Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Charles E Hill
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - T Mark Beasley
- Biostatistics, Section on Statistical Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Deborah A Nickerson
- Genome Sciences, School of Medicine, University of Washington, Seattle, Washington
| | - Nita A Limdi
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
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Fohner AE, Robinson R, Yracheta J, Dillard DA, Schilling B, Khan B, Hopkins S, Boyer B, Black J, Wiener H, Tiwari HK, Gordon A, Nickerson D, Tsai JM, Farin FM, Thornton TA, Rettie AE, Thummel KE. Variation in genes controlling warfarin disposition and response in American Indian and Alaska Native people: CYP2C9, VKORC1, CYP4F2, CYP4F11, GGCX. Pharmacogenet Genomics 2015; 25:343-353. [PMID: 25946405 PMCID: PMC4461509 DOI: 10.1097/fpc.0000000000000143] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Pharmacogenetic testing is projected to improve health outcomes and reduce the cost of care by increasing therapeutic efficacy and minimizing drug toxicity. American Indian and Alaska Native (AI/AN) people historically have been excluded from pharmacogenetic research and its potential benefits, a deficiency we sought to address. The vitamin K antagonist warfarin is prescribed for prevention of thromboembolic events, although its narrow therapeutic index and wide interindividual variability necessitate close monitoring of drug response. Therefore, we were interested in variation in CYP2C9, VKORC1, CYP4F2, CYP4F11, and GGCX, which encode enzymes important for the activity of warfarin and synthesis of vitamin K-dependent blood clotting factors. METHODS We resequenced these genes in 188 AI/AN people in partnership with Southcentral Foundation in Anchorage, Alaska and 94 Yup'ik people living in the Yukon-Kuskokwim Delta of southwest Alaska to identify known or novel function-disrupting variation. We conducted genotyping for specific single nucleotide polymorphisms in larger cohorts of each study population (380 and 350, respectively). RESULTS We identified high frequencies of the lower-warfarin dose VKORC1 haplotype (-1639G>A and 1173C>T) and the higher-warfarin dose CYP4F2*3 variant. We also identified two relatively common, novel, and potentially function-disrupting variants in CYP2C9 (M1L and N218I), which, along with CYP2C9*3, CYP2C9*2, and CYP2C9*29, predict that a significant proportion of AI/AN people will have decreased CYP2C9 activity. CONCLUSION Overall, we predict a lower average warfarin dose requirement in AI/AN populations in Alaska than that seen in non-AI/AN populations of the USA, a finding consistent with clinical experience in Alaska.
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Affiliation(s)
- Alison E Fohner
- Department of Pharmaceutics, University of Washington, Seattle, WA
| | | | - Joseph Yracheta
- Department of Pharmaceutics, University of Washington, Seattle, WA
| | | | | | | | - Scarlett Hopkins
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, AK
| | - Bert Boyer
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, AK
| | - Jynene Black
- Center for Alaska Native Health Research, University of Alaska Fairbanks, Fairbanks, AK
| | - Howard Wiener
- School of Public Health, University of Alabama at Birmingham, Birmingham, AL
| | - Hemant K Tiwari
- School of Public Health, University of Alabama at Birmingham, Birmingham, AL
| | - Adam Gordon
- Department of Genome Sciences, University of Washington, Seattle WA
| | | | - Jesse M Tsai
- Department of Environmental and Occupational Health Sciences, University of Washington
| | - Federico M Farin
- Department of Environmental and Occupational Health Sciences, University of Washington
| | | | - Allan E Rettie
- Department of Medicinal Chemistry, University of Washington
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