title: The c.-1639G>A polymorphism of the VKORC1 gene in Serbian population: retrospective study of the variability in response to oral anticoagulant therapy.
abstract: 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). 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. We conducted a retrospective cohort analysis of 200 stable anticoagulation patients followed from the initiation of VKA. 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 < 0.0001). Carriers of AA genotype were more likely to be overanticoagulated during follow-up after initiation of VKA when compared with carriers of the GA and GG genotypes (P < 0.0001). Patients with GG genotype spent more time below therapeutic range compared with patients carriers of AA (P = 0.0328) and GA genotype (P < 0.0001). 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 of anticoagulation.
authors.affiliation: Blood Transfusion Institute of Serbia, Svetog Save 39a, Serbia.
authors.forename: Mirjana K
authors.initials: MK
authors.lastname: Kovac
authors.forename: Aleksandar R
authors.initials: AR
authors.lastname: Maslac
authors.forename: Ljiljana B
authors.initials: LB
authors.lastname: Rakicevic
authors.forename: Dragica P
authors.initials: DP
authors.lastname: Radojkovic
mesh_terms: D000074:Acenocoumarol / Q000008:administration & dosage; D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000494:pharmacology* / Q000627:therapeutic use; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000235:genetics*; D010597:Pharmacogenetics / Q000379:methods*; D020641:Polymorphism, Single Nucleotide; D012189:Retrospective Studies; D055771:Serbia / Q000453:epidemiology; D014812:Vitamin K / Q000037:antagonists & inhibitors; D064417:Vitamin K Epoxide Reductases; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D014812:Vitamin K; D006899:Mixed Function Oxygenases; C578523:VKORC1 protein, human; D064417:Vitamin K Epoxide Reductases; D000074:Acenocoumarol