INTRODUCTION: A substantial part of the inter-individual variation in vitamin K-antagonist dose can be explained by certain sequence variants in the genes CYP2C9 (NG_008385.1:g.8633C>T or *1/*2, NG_008385.1:g.47639A>C or *1/*3) and VKORC1 (NG_011564.1:g.6399C>T). Patients possessing these variant alleles require lower doses and have increased risk of overanticoagulation. METHODS: We investigated the influence of the above sequence variants on stability of maintenance phase warfarin therapy in a prospective study of 300 consecutive patients followed for one year at an anticoagulant clinic. RESULTS: Patients having one VKORC1 variant allele (n=144) had a time in therapeutic range of INR (TTR) of 71.4%, significantly lower (p=0.02) than the 76.7% TTR of patients with none (n=96) or two (n=46) variant alleles. Patients carrying the CYP2C9 *3 allele (n=40) trended towards lower TTR than patients without this variant allele (69.8% vs. 74.7%, p=0.09). Six patients possessed two variant alleles of CYP2C9 (*2/*3 or *3/*3) and had significantly lower TTR (60.5% vs. 74.3%, p=0.012) and higher risk of an INR>4.5 (67% vs. 23%, p=0.03) compared with the remaining patients. CONCLUSIONS: We observed modest effects of common gene sequence variants in CYP2C9 and VKORC1 on stability of maintenance phase warfarin therapy. Patients attending an anticoagulant clinic using computer-assisted dosage were safely monitored regardless of these sequence variants, but for the small subgroup of patients with the CYP2C9 genotype *2/*3 or *3/*3, treatment stability was reduced.
INTRODUCTION: A substantial part of the inter-individual variation in vitamin K-antagonist dose can be explained by certain sequence variants in the genes CYP2C9 (NG_008385.1:g.8633C>T or *1/*2, NG_008385.1:g.47639A>C or *1/*3) and VKORC1 (NG_011564.1:g.6399C>T). Patients possessing these variant alleles require lower doses and have increased risk of overanticoagulation. METHODS: We investigated the influence of the above sequence variants on stability of maintenance phase warfarin therapy in a prospective study of 300 consecutive patients followed for one year at an anticoagulant clinic. RESULTS:Patients having one VKORC1 variant allele (n=144) had a time in therapeutic range of INR (TTR) of 71.4%, significantly lower (p=0.02) than the 76.7% TTR of patients with none (n=96) or two (n=46) variant alleles. Patients carrying the CYP2C9 *3 allele (n=40) trended towards lower TTR than patients without this variant allele (69.8% vs. 74.7%, p=0.09). Six patients possessed two variant alleles of CYP2C9 (*2/*3 or *3/*3) and had significantly lower TTR (60.5% vs. 74.3%, p=0.012) and higher risk of an INR>4.5 (67% vs. 23%, p=0.03) compared with the remaining patients. CONCLUSIONS: We observed modest effects of common gene sequence variants in CYP2C9 and VKORC1 on stability of maintenance phase warfarin therapy. Patients attending an anticoagulant clinic using computer-assisted dosage were safely monitored regardless of these sequence variants, but for the small subgroup of patients with the CYP2C9 genotype *2/*3 or *3/*3, treatment stability was reduced.
Authors: Sherif M M Ekladious; Marianne Samir M Issac; Sahar Abd El-Atty Sharaf; Hazem S Abou-Youssef Journal: Mol Diagn Ther Date: 2013-12 Impact factor: 4.074
Authors: Marcus Fernando S Praxedes; Maria Auxiliadora P Martins; Aline O M Mourão; Karina B Gomes; Edna A Reis; Renan P Souza; Emílio Itamar F Campos; Daniel D Ribeiro; Manoel Otávio C Rocha Journal: Eur J Clin Pharmacol Date: 2019-11-12 Impact factor: 2.953
Authors: Maria Mariana Barros Melo da Silveira; Leiliandry de Araújo Melo; Filipe Maia Ferreira Gomes; Leonardo José de Cupertino Barreto da Rocha Andrade; Isabela Paulino Serur; Isabelle Cecília de Vasconcellos Piscoya; Raposo Marina Gueiros; Kleyton Palmeira do Ó; Raul Emídio de Lima; Victor Arthur Eulálio Brasileiro; Luydson Richardson Silva Vasconcelos; Dário Celestino Sobral Filho Journal: Appl Clin Genet Date: 2019-08-02