Prevalence and Association of the Factor V Leiden and Prothrombin G20210A in Healthy Subjects and Patients with Venous Thromboembolism

Aim: To determine the prevalences of factor V Leiden and the G20210A mutation in the prothrombin gene (PT20210A) and the frequency of their association in healthy subjects and in patients with venous thromboembolism (VTE).

Method: We studied 160 Croatian patients with at least one episode of VTE and 155 healthy subjects as a control group. Genomic DNA was extracted according to standard procedures and the presence of factor V Leiden and PT20210A were determined by polymerase chain reaction-restriction fragment length polymorphism method.

Results: The prevalences of factor V Leiden and PT20210A were in VTE patients 21% and 8% respectively, and 4% in controls for both mutations. Additionally, 4 patients were affected by double heterozygous defects, corresponding to a frequency of 3%, whereas none of the controls were double heterozygotes. The coexistence of the PT20210A in heterozygous carriers of factor V Leiden was 15% in VTE group. The results obtained for different subgroups of VTE patients showed that the carriers of analyzed mutations were identified only in subgroups of patients with deep venous thrombosis of lower extremities (in 30 patients with factor V Leiden and in 13 patients with PT20210A) and superficial venous thrombosis (in 3 patients with factor V Leiden).

Conclusion: The prevalences of factor V Leiden and PT20210A in analyzed population of VTE patients are higher than in the group of healthy subjects. High frequency of association between both mutations supports the need to perform simultaneous genetic analyses of factor V Leiden and PT20210A in all VTE patients.