CE: Swati; MBC/200710; Total nos of Pages: 6; MBC Original article 1. Blood Coagulation and Fibrinolysis 2010, 21:

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1 Original article 1 The c.-1639g>a polymorphism of the VKORC1 gene in Serbian population: retrospective study of the variability in response to oral anticoagulant therapy Mirjana K. Kovac a, Aleksandar R. Maslac a, Ljiljana B. Rakicevic b and Dragica P. Radojkovic b Background A single nucleotide polymorphism c.-1639g>a in the promoter region of vitamin K-epoxide reductase (VKORC1) gene has been found to account for most of the variability in response to oral vitamin K antagonist (VKA). Objective Our aim was to study the effect of c.-1639g>a polymorphism on the acenocoumarol dosage requirements in a group of patients under stable anticoagulation, and to estimate the variability in response to VKA. Patients and methods We conducted a retrospective cohort analysis of 200 stable anticoagulation patients followed from the initiation of VKA. Results Out of 43 low-dose patients, 40 (93%) carried the A allele. The A allele was less frequent in the group of 30 patients requiring high VKA dose among these patients 13 (43.3%) carried the A allele in the heterozygous form and none of them carried AA genotype. Patients with GG genotype required 2.6 times higher dose than patients carriers of AA genotype (P < ). Carriers of AA genotype were more likely to be overanticoagulated during follow up after initiation of VKA when compared with carriers of GA and GG genotype (P < ). Patients with GG genotype spent more time below therapeutic range compared with patients carriers of AA (P U ) and GA genotype (P < ). Conclusion VKORC1 c.-1639g>a polymorphism significantly influenced VKA dose and represented a good predictor of individuals predisposed to unstable anticoagulation. Pharmacogenetic testing could predict a high risk of overdose among 28.5% of our patients, carriers of AA genotype, before the initiation anticoagulation. Blood Coagul Fibrinolysis 21: ß 2010 Wolters Kluwer Health Lippincott Williams & Wilkins. Blood Coagulation and Fibrinolysis 2010, 21: Keywords: acenocoumarol dose, c G>A polymorphism, variability in response to VKA, VKORC1 a Blood Transfusion Institute of Serbia, Svetog Save 39a and b Institute of Molecular Genetics and Genetic Engineering, Vojvode Stepe 444a, Belgrade, Serbia Correspondence to Ljiljana Rakicevic, Institute of Molecular Genetics and Genetic Engineering, Vojvode Stepe 444a, P.O. Box 23, Belgrade, Serbia lilijar@eunet.rs Received 2 February 2009 Revised 20 April 2010 Accepted 27 April 2010 Introduction Oral vitamin K antagonist (VKA), including warfarin and acenocoumarol, are the most widely prescribed drugs for the prevention and treatment of patients with arterial and venous thromboembolic disorders [1]. The effectiveness and safety of VKA depend on maintaining the prothrombin time, expressed as the international normalized ratio (INR) within the therapeutic range [2]. Clinical use of VKA is further complicated by substantial risk for haemorrhagic side effects, which is increased in patients with low-dose requirements [3]. The required dose of VKA for maintaining the prothrombin time is variable, and depends on several acquired factors such as age, dietary intake, interaction with other drugs and intercurrent illness [2,4]. In addition to acquired factors, it is well known that response to VKA is genetically determined. The first gene documented to influence VKA dose requirement was CYP2C9. It encodes the enzyme cytochrome P450 2C9 the main enzyme responsible for the hepatic metabolism of VKA [5]. Two common variants of the CYP2C9 gene, 2and3are associated with reduced enzyme activity, resulted in deficient VKA clearance. Individuals who carry deficient CYP2C9 alleles are sensitive and have lower VKA dose requirements. Nevertheless, only a small part (7 10%) of the interindividual variation could be explained by these polymorphisms [6]. Vitamin K epoxide reductase (VKORC1) is the key enzyme of the vitamin K cycle and the molecular target of coumarin derivates and it was found to determine up to 40% of individual coumarin dose requirement. VKORC1 recycles vitamin K 2,3-epoxide to vitamin K-hydroquinone. Vitamin K-hydroquinone is the cofactor for the carboxylase that adds a molecule of carbon dioxide to glutamic acid, producing g-carboxyglutamic acid (g- Glu). The g-glu residues are essential for some clotting factors, such as factors II, VII, IX, X and protein C, S Z, to bind phospholipids and thus be functional [5]. Mutations in VKORC1 cause two distinctive phenotypes. Those affecting VKORC1 function lead to vitamin K dependent coagulation factors deficiency type ß 2010 Wolters Kluwer Health Lippincott Williams & Wilkins DOI: /MBC.0b013e32833c2988

2 2 Blood Coagulation and Fibrinolysis 2010, Vol 00 No 00 (VKCFD2), confirming critical role of that enzyme in vitamin K dependent coagulation factors function [5]. On the contrary, several genetic variations of the VKORC1 gene have been found to influence sensitivity to VKA [5,7]. Twenty-eight polymorphisms have been described, constituting three main haplotypes covering almost the whole genetic variability of VKORC1, with the following distribution in Caucasians VKORC12, 42%, VKORC13, 38% and VKORC14, 20% [6]. Haplotype VKORC12 includes a single nucleotide polymorphism in the promoter region (c.-1639g>a) and has been found to account for most of the variability in response to VKA [6,7]. Several studies clearly showed a strong association of initial variability in the INR response to VKA with VKORC1 genetic variability. Carriers of AA genotype had decreased time to the first INR within therapeutic range and also to the first INR above 4 [8,9]. Our aim was to study the effect of c.-1639g>a polymorphism on the acenocoumarol dosage requirements in a group of patients under stable anticoagulation. We also aimed to estimate the rate of bleeding during initiation of the VKA, and variability in therapeutical response, in regard to the presence of c.-1639g>a polymorphism. Materials and methods Data collection A total of 200 outpatients attending the Hemostasis Department of the Blood Transfusion Institute of Serbia, who had maintained stable anticoagulation with acenocoumarol for at least 3 months, were included in the study. We considered a patient on stable anticoagulation whose acenocoumarol dose requirement had remained constant for at least three previous months, and was enough to keep the INR within therapeutic ranges, according to the indication for VKA treatment. In order to minimize the possible influence of hepatic, renal or malignant disease, which could have pharmacodynamic influence, on increased prothrombin time (INR) and possible bleeding complications, patients with hepatic, renal or malignancy were excluded from the study. Likewise, all patients treated with amiodaron, which have synergistic influence due to pharmacokinetic mechanisms on increased INR were excluded. In total, 116 male and 84 female patients were included in the study, median age 61 years (range 20 82). On the arrival in the laboratory, a blood sample was taken for INR measurement and genotyping. Genotyping was performed by polymerase chain reaction followed by digestion with MspI (New England Biolabs) as previously described [10]. Furthermore, a retrospective analysis of medical records was performed to investigate the potential influence of VKORC1 genotype on oral anticoagulants response in the initiation phase and during a follow up from the start of VKA administration. Complete data on acenocoumarol doses and INR were registered from medical records, as well as the data on age, sex, indication for treatment, concomitant medications and medications potentially interacting with VKA. Patients were subjected to the VKA treatment according to standard care without specific warfarin dosing algorithms. The average initial acenocoumarol dose was mg. Therapeutic INR was defined as INR between two and three irrespective of the individual target range. A minimum of three consecutive therapeutic INR measurements denoted stable anticoagulation. Maintenance dose was defined as the mean of all doses given to a patient during stable anticoagulation. Stable maintenance dose was calculated from weekly doses that were unchanged over a minimum of three consecutive measurements of three therapeutic INR. INR was checked in all patients three times in the first, twice in the second week, and weekly during the achievement therapeutic INR. Upon the achievement of stable anticoagulation dose, the INR was measured less frequently, usually every 4 weeks. Follow up period ranged from one to 8 years per patient, average 3.9 years. Considering the present maintenance dose, study population consisted of 43 consecutive patients requiring low (7 mg per week or less), 127 consecutive patients requiring medium (7 28 mg per week) and 30 consecutive patients requiring high-acenocoumarol dose (28 mg per week or more). Number of bleeding complications, as well as the size and localization of bleeding recorded during the first 3 months of VKA initiation, were analyzed completely. The variability of INR regarding INR more than four and INR less than two were evaluated during follow up from initiation of VKA. We calculated number of INR more than four or less than two from the first stable anticoagulation, and took in consideration only patients who had change of INR without change of VKA doses as well as possible influence of dietary change, intercurrent illness or interaction with other drugs. All individuals had signed informed consent to participate in the study and the local ethics committee approved the study. Statistical analysis Differences in the acenocoumarol requirement between patients who were carriers, and noncarriers of c.-1639g>a polymorphism in the low-dose, medium-dose and highdose group were assessed with chi-squared test. Differences between homozygotes (AA) and heterozygotes (GA) regarding the overdosed patients and the presence of bleeding complication were assessed using chi-squared test or Fisher s exact test. Differences between overdosed patients with AA and GA genotype, regarding the level of INR and age, were assessed with Student s t-test. All the statistical analyses were performed according to the

3 VKORC 1 polymorphism and response to acenocoumarol Kovac et al. 3 AQ5 Table 1 Characteristics of study population Fig. 1 Age (median range) 61 (20 82) Male n (%) 116 (58%) Female n (%) 84 (42%) Primary reason for anticoagulation n (%) AF/valve replacement 157 (78%) DVT/PE 43 (22%) Daily acenocoumarol dose (mg) Low 43 (21.5%) Medium 127 (63.5%) High 30 (15%) VKORC1 (c.-1693g/a) Homozygous (AA) 57 (28.5%) Heterozygous (GA) 90 (45%) Wild type 53 (26.5%) AF, atrial fibrillation; DVT, deep venous thrombosis; PE, pulmonary embolism; VKORC1, vitamin K-epoxide reductase. Table 2 Frequency of different genotypes for the c.-1639g>a polymorphism of the VKORC1 gene in three groups of patients with different acenocoumarol dose requirements Genotype Low dose n ¼ 43 Medium dose n ¼ 127 High dose n ¼ 30 Acenocoumarol maintenance dose (mg per week) AA n = 57 Min - Max Mean ± SD Mean AG n = 90 AA - homozygous AG - heterozygous GG - wild type GG n = 53 P < 0.01 AA 25 (58.1%) 32 (25.2%) 0 (0%) GA 15 (34.9%) 62 (48.8%) 13 (43.3%) GG 3 (7%) 33 (26%) 17 (56.7%) P M M M M Difference AA GA. Difference AA GG. Difference GA GG. Statistical Package for Social Science SPSS software, Inc. Chicago, Illinois, USA). A P value of less than 0.05 was considered as statistically significant. Results Characteristics of the studied population and the distribution of the G and A alleles of c.-1639g >A polymorphism are shown in Table 1. In 57 (28.5%) patients AA genotype was present, in 90 (45%) GA and 53 (26.5%) patients were carriers of GG genotype. The frequencies of genotypes of the c.-1639g>a polymorphism regarding the requirement dose of acenocoumarol are shown in Table 2. The allelic distribution was different across the various acenocoumarol dosage groups. In the group of 43 patients who maintained stable anticoagulation with the low dose of acenocoumarol, 40 patients (93%) carried the A allele. The A allele was less frequent in the group of 30 patients requiring a high-acenocoumarol dose among these patients 13 (43.3%) carried the A allele in the heterozygous form The range of acenocoumarol dose obtained from patients with different genotypes for the c.-1639g>a polymorphism of the VKORC1 gene. and none of them carried AA genotype. In groups with low and high dose, we observed statistically significant difference among patients with different genotypes, whereas in the group with medium dose, statistical difference between patients carriers of different genotypes was not observed (Table 2). Figure 1 shows the range and mean requirements dose of acenocoumarol for patients carrying different alleles. In group with AA genotype, the mean acenocoumarol dose per week for the maintenance of stable anticoagulation was 10 mg (range 2 21), in group with GA genotype 19 mg (range 6 49), and in group with GG genotype 26 mg (range 8 70). The patients with GG genotype required 2.6 times higher dose than patients carriers of AA genotype (P < ). Retrospective analysis showed that only patients who carried A allele experienced problems during the initiation of anticoagulation therapy (Table 3). The data showed that 33 (16.5%) patients were overdosed during the initiation of VKA and in 11 (5.5%) this was further complicated by bleeding at different localizations (4 patients had mellena, 2 haematuria, 4 haematoma and Table 3 The overdosed patients during initiation of accenocoumarol regarding the presence of polymorphism c.-1639g>a Genotype AA (N ¼ 57) GA (N ¼ 90) GG (N ¼ 53) P Overdosed patients n (%) 27 (47) 6 (7) 0 < Overdosed patients with bleeding n (%) 8 (14) 3 (3) INR mean (range) Overdosed 6.2 (4.2 12) 4.9 ( ) NA Overdosed with bleeding 7.5 (4.9 12) 4.5 (4.15 5) NA INR, international normalized ratio; NA, not applicable.

4 4 Blood Coagulation and Fibrinolysis 2010, Vol 00 No 00 Table 4 Patients with INR more than four during follow up from initiation of VKA regarding the presence of polymorphism c.-1639g>a AA (N ¼ 57) GA (N ¼ 90) GG (N ¼ 53) Patients n (%) 31 (54) 14 (16) 4 (8) Number of INR > Num. of INR > 4 per patient Patients with bleeding n (%) 1 (1.8) 1 (1) 0 P < M, P < , P ¼ epistaxis). In the group of 33 overdosed patients, 27 had AA genotype, and six carried GA genotype (P < ). In the group of patients who carried AA genotype, the mean value of INR level in overdosed patients was 6.2 (4.2 12), whereas in the group with GA genotype the mean INR was 4.9 ( ). A statistically significant difference (P ¼ ) was observed between groups. The mean age of overdosed patients with bleeding complication, was 69 years, (range 50 81) and in the group of overdosed patients without bleeding, 59 years (26 71) representing statistically significant difference (P ¼ ). In the follow up period from initiation of VKA, INR more than four was recorded 149 times in 31 (54%) carriers of AA genotype. In 14 (16%) patients with GA genotype INR more than four were recorded 72 times, whereas in four (8%) patients with GG genotype INR more than four was recorded 11 times. Patients carriers of AA genotype were more likely to be overanticoagulated during follow up after initiation of VKA compared with GA genotype, P < and respectively with GG genotype, P < (Table 4). Patients with GG genotype spent more time below therapeutic range compared with patients carriers of AA (P ¼ ) and GA genotype (P < ). In 11 patients (19%) with AA genotype, INR less than two was recorded 62 times. In seven (8%) patients with GA, INR less than two was recorded 51 times, and in 21 (40%) with GG genotype, INR less than two was recorded 73 times during follow up of initiation of VKA (Table 5). Discussion Recently, genetic variations within the gene encoding for a subunit of the vitamin K epoxide reductase complex, have been found to predict sensitivity to anticoagulant Table 5 Patients with INR less than two during follow up from initiation of VKA regarding the presence of polymorphism c.-1639g>a AA (N ¼ 57) GA (N ¼ 90) GG (N ¼ 53) Patients n (%) 11 (19) 7 (8) 21 (40) Number of INR < Num. of INR < 2 per patient P ¼ M, P ¼ , P < therapy. The c.-1639g>a polymorphism marks the VKORC12 haplotype [5], and its association with increased response to acenocoumarol has been shown in a group of healthy individuals [6], as well as in a group of patients treated with warfarin or acenocoumarol [7 15]. The aim of our study, which represents the first one ever performed in our population, was to evaluate the effect of the c.-1639g>a polymorphism on the acenocoumarol dosage requirements in a group of patents under stable anticoagulation. The rate of bleeding during the initiation of VKA and variability in response during follow up, considering the presence of this polymorphism, were also evaluated. Our study supports the importance of the role of c G>A in the sensitivity to acenocoumarol. In the group of patients who maintained stable anticoagulation with low doses of acenocoumarol, 93% carried the A allele, whereas this allelic variant was present in 43.3% patients requiring high doses and in 74% patients in the medium-dose group. None of the patients who carried AA genotype was in the group requiring high-acenocoumarol dose, and statistically significant difference was observed only in groups with low and high dose, among patients with different genotypes. Similar results were demonstrated by Montes et al. [10]. They found that more than 90% of the patients required low doses of acenocoumarol, and less than 30% of the patients who needed a high dose carried the A allele. Likewise, in the study performed by Geisen et al. [7], 93% patients with the increased coumarin sensitivity and none of the patients with partial coumarin resistance, were found to be homozygous for the A allele (representing VKORC 12). In our study, the mean acenocoumarol dose per week in the group with AA genotype, required for the maintenance of stable anticoagulation was 10 mg, in the group with GA genotype 19 mg, and in the group with GG genotype 26 mg. The data show that patients with GG genotype required 2.6 times higher dose than patients who were carriers of AA genotype. In a similar study by Qazim et al. [13] the mean phenprocoumon dosage per week to achieve therapeutic VKA was 15.3 mg in patients without the VKORC1 c.-1639g>a gene polymorphism, 10.9 mg in patients carrying the heterozygous and 7.8 mg in patients carrying the homozygous c.-1639g>avkorc1 polymprphism. Sonce et al. [14] also showed that the mean warfarin dose was the highest in patients with GG genotype compared with the GA and AA genotype patients, and in patients who are homozygous wild type for CYP2C9. In order to estimate the optimum initial warfarin dose needed to maintain stable and optimum anticoagulation they proposed dosing algorithm that incorporate the contribution of genetic (VKORC-1639, 2C93) and nongenetic variables (age, height) [14]. AQ1

5 VKORC 1 polymorphism and response to acenocoumarol Kovac et al. 5 AQ2 Oral anticoagulant therapy, particularly during the initiation period, is associated with the overanticoagulaton that may result in bleeding. Therefore, we estimated the rate of overanticoagulation patients regarding the presence of c.-1639g>a polymorphism during the first 3 months of the initiation. Our results showed that only patients who carried A allele were at risk of overanticoagulation. In the group of 33 overdosed patients, 27 carried AA genotype, and six carried GA genotype. From those in the overdosed group, 11 patients (5.5%) had overanticoagulation further complicated with bleeding and five of them had to be transfused with fresh frozen plasma to stop the bleeding and reverse the INR to therapeutic range. Our results suggest that performing of pharmacogenetic testing for the presence of c.-1639g>a prior to the initiation of VKA, could minimize the risk of overanticoagulation and subsequent bleeding complications in our patients. Regarding the mean INR in overdosed patients, a statistically significant difference was observed between carriers of AA and GA genotype (P ¼ ), whereas between carriers of AA and GA genotype who had bleeding complications, no statistical difference was observed regarding the mean INR, possible due the small number of patients carriers of GA genotype. Schwartz et al. [8] reported that patients carriers of AA genotype, had significantly higher INR values in the first week than non-a homozygotes. They also found that the patients with one or two VKORC1 haplotype A alleles had shorter times to the first INR more than four. They reported the association of an increase in the anticoagulant response in these patients, as indicated by an INR above the therapeutic range, and an increased risk of bleeding [8]. Contrary to our findings, Wadelius et al. [9] did not find an association between VKORC1 polymorphism and risk of bleeding, but they emphasized that homozygosity for VKORC1 c.-1639g>a variant alleles increased the risk of early INR over four. They showed the strongest association with dose, which was observed for VKORC1, and significantly lower for CYP2C9 [9]. The mean age of overdosed patients with bleeding complications in our study was 69 years, (range 50 81), whereas in overdosed group without bleeding it was 59 years (range 26 71). P ¼ , supports the early investigation stating that elderly patients were at a higher risk of bleeding [16]. Our findings were similar to study by Schwartz et al. [8] in which patients with bleeding events older (median age, 71 years) than the ones in studied population (median age, 61 years) were included. In our study after initiation of VKA, INR more than 4 were recorded in 54% carriers of AA genotype, 16% with GA genotype and in 8% with GG genotype. Patients carriers of AA genotype were more likely to be overanticoagulated during follow up after initiation of VKA compared carriers of GA genotype and GG genotype, P less than Osman et al. [12] also reported more variations in INR in patients with VKORC12 than those with VKORC13 or VKORC14 haplotypes, in the initiation phase which could be connected with an increased risk of bleeding complications. Our patients with GG genotype spent more time below therapeutic range compared with patients carriers of AA (P ¼ ) and GA genotype (P < ). Similarly, Meckley et al. [17] showed in a retrospective study that patients with GG genotype spent more time below therapeutic INR compared with patients carriers of A allele. In summary, even with careful monitoring, initiation of VKA is associated with highly variable responses between individuals and maintaining levels within the narrow therapeutic range that can lead to adverse-drug events. For that reason, the use of every tool that contributes to properly estimation of VKA dosage is a considerable asset. In planning of optimal initial and maintenance doses, in addition to the age, height and intercurrent illness, genotype plays an important role, especially if the using of computer dosing software is not available and patients are subjected to treatment according to standard care without specific dosing algorithm. Testing for VCKORC1 c G>A polymorphism predicts high risk of overdose among third of our patients. Therefore, on the basis of the results obtained from this study, testing for VCKORC1 c G>A may be considered as a preliminary examination before starting anticoagulation in order to increase effectiveness and safety of anticoagulation therapy. Acknowledgements This work supported by grant from Ministry of Science, Republic of Serbia. References 1 Hirsh J. Oral anticoagulant drugs. N Engl J Med 1991; 324: Baglin TP, Keeling DM, Watson HG. Guidelines on oral anticoagulation (warfarin): third edition 2005 update. Br J Haematol 2006; 132: Dentali F, Ageno W, Crowter M. Treatment of coumarin-associated coagulopathy: a systemic review and proposed treatment algorithms. J Thromb Haemost 2006; 4: Wittkovsky AK. Drug interactions with oral anticoagulants. In: Colman RW, Clowes AW, Goldhaber SZ, Marder VJ, George JN, editors. Hemostasis and Thrombosis, 5th ed. Philadelphia: Lippincott Williams & Wilkins; pp Oldenburg J, Watzka M, Rost S, Muller R. VKORC1: molecular target of coumarins. J Thromb Haemost 2007; 5 (suppl1): Bodin L, Verstuyft C, Tregouet DA, Robert A, Dubert L, Funck-Brentano C, et al. Cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase (VKORC1) genotypes as determinants of acenocumarol sensitivity. Blood 2005; 106: Geisen C, Watzka M, Sittinger K, Steffens M, Daugela L, Seifried E, et al. VKORC1 haplotypes and their impact on the inter-individual and interethnical variability of oral anticoagulation. Thromb Haemost 2005; 94: Schwartz UI, Ritchie MD, Bredford Y, Chun L, Dudec S, Frye-Anderson, et al. Genetic determinants of response to warfarin during initial anticoagulation. N Engl J Med 2008; 358: Wadelius M, Chen LY, Lindh JD, Eriksson N, Ghori M JR, Bumpstead S, et al. The largest prospective warfarin-treated cohort supports genetic forecasting. Blood 2008; 4: AQ3 AQ4

6 6 Blood Coagulation and Fibrinolysis 2010, Vol 00 No Montes R, Ruiz de Gaona E, Martinez-Gonzales MA, Alberca I, Hermida J. The c.-1639g>a polymorphism of the VKORC1 gene is a major determinant of the response to acenocoumarol in anticoagulated patients. B J Haematol 2006; 133: D Andrea G, D Ambrosio LC, Di Perna P, Chetta M, Santacroce R, Brancaccio V, et al. A polymorphism in the VKORC1 gene is associated with an interindividual variability in the dose-anticoagulant effect of warfarin. Blood 2005; 105: Osman A, Enstrom C, Arbring K, Soderkvist P, Lindhal TL. Main haplotypes and mutational analysis of vitamin K epoxide reductase (VKORC1) in a Swedish population: retrospective analysis of case records. J Thromb Haemost 2006; 4: Qazim B, Stollberger C, Krugluger W, Dossenbach-Glaninger A, Finsterer J. Dependency of phenprocoumon dosage on polymorphisms in the VKORC1 and CYP2C9 genes. J Thromb Thrombolysis 2008; 28: Sonce E, Kahn T, Wynne H, Avery P, Monkhouse L, King B, et al. The impact of CYP2C9 and VKORC1 genetic polymorphism and patient characteristics upon warfarin dose requirement: proposal for a new dosing regimen. Blood 2005; 106: Quteinech L, Verstuyft C, Descot C, Dubert L, Robert A, Jaillon P, et al. Vitamin K epoxide reductase (VKORC1) genetic polymorphism is associated to oral anticoagulant overdose. Thromb Haemost 2005; 94: Levine MN, Beyth R, Kearon C, Schulman S. Hemorrhagic complications of anticoagulant treatment. Chest 2004; 126:287S 310S. 17 Meckley LM, Wittkowsky AK, Rieder MJ, Rettie AE, Veenestra DL. An analysis of the relative effects of VKORC1 and CYP2C9 variants on anticoagulation related outcomes in warfarin-treated patients. Thromb Haemost 2008; 100:

7 MBC Manuscript No Blood Coagulation & Fibrinolysis Typeset by Thomson Digital for Lippincott Williams & Wilkins Dear Author, During the preparation of your manuscript for typesetting, some queries have arisen. These are listed below. Please check your typeset proof carefully and mark any corrections in the margin as neatly as possible or compile them as a separate list. This form should then be returned with your marked proof/list of corrections to the Production Editor. QUERIES: to be answered by AUTHOR/EDITOR QUERY NO. QUERY DETAILS RESPONSE <AQ1> Please check edit in this statement for correctness. 'Sonce et al. [14] for CYP2C9.' <AQ2> Please check edit in the spelling of author name in this statement for correctness. 'Schwartz et al. [8] homozygotes. <AQ3> Please check edits in article title of Refs. [2,11] for correctness. <AQ4> <AQ5> Please check details of Ref. [9] for correctness. Please check edit in Tables [1 5] for correctness.

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