Factor II (Prothrombin), DNA Analysis

Venous thromboembolism is a multifactorial disease influenced by genetic, environmental, and circumstantial risk factors. The c.*97G>A variant in the F2 gene is a genetic risk factor for venous thromboembolism. Heterozygous carriers have a 2- to 4-fold increased risk for venous thromboembolism. Homozygotes for the c.*97G>A variant are rare. The annual risk of VTE in homozygotes has been reported to be 1.1% per year. Individuals who carry both a *97G>A variant in the F2 gene and a c. 1601G>A (p.Arg534Gln) variant in the F5 gene (commonly referred to as Factor V Leiden) have an approximately 20-fold increased risk for venous thromboembolism. Risks are likely to be even higher in more complex genotype combinations involving the F2 c.*97G>A variant and Factor V Leiden.¹ Additional risk factors include but are not limited to: deficiency of protein C, protein S, or antithrombin III-, age, male sex, personal or family history of deep vein thromboembolism, smoking, surgery, prolonged immobilization, malignant neoplasm, tamoxifen treatment, raloxifene treatment, oral contraceptive use, hormone replacement therapy, and pregnancy. Management of thrombotic risk and thrombotic events should follow established guidelines and fit the clinical circumstance. This result cannot predict the occurrence or recurrence of a thrombotic event. Genetic coordinators are available for health care providers to discuss results and for information on how to order additional testing, if desired, at 1-800-345-GENE.