Combined Factor V Leiden (R506Q) and prothrombin G20210A genotyping in young patients presenting with deep venous thrombosis

Objective: To evaluate the association between the Factor V Leiden (FV R506Q) and prothrombin gene (FII G20210A) mutations and deep venous thrombosis (DVT) in young people. Methods: Blood samples were drawn from 199 subjects: 100 healthy controls and 99 unselected patients, with an objectively documented first episode of DVT under 40 years old. DNA analysis was performed using the polymerase chain reaction. Results: The mean age in the patient cohort was 27 years (range 16-40) and 68 (68.7%) were women. Patient prevalences were 20.6% and 10.1% for FV R506Q and FII G20210A, respectively. In the control group, carrier frequencies were 2% and 5%, respectively. We found an increased overall relative risk of DVT with statistical significance for FV R506Q carriers (OR: 12.8; 95% Cl: 2.9-56.7; P<0.001), but not for FII G20210A mutation (OR: 2.1; 95% Cl: 0.7-6.5; P = 0.19). Conclusions: Our results suggest a possible increase in DVT risk for the young G20210A allele carriers, which can be more expressed in the presence of a circumstantial risk factor. There is extremely strong evidence that the Factor V Leiden mutation is an important risk factor in the development of a first episode of DVT in young people.