Factor V Leiden (rs6025) and the prothrombin G20210A mutation (rs1799963) are the most common prothrombotic variants (incidence of 3–5%) in young and middle-aged populations, and are associated with a three- to seven-fold increase in the risk of venous thrombosis, compared with non-carriers [210,211,212]. Here, F2 is linked to Venous thrombosis.