Moreover, other thrombophilic gene polymorphisms, such as PAI-1 4G/5G, factor V Leiden G1691A, prothrombin G20210A and antithrombin III deficiency, have been implicated in APS, especially for increasing the risk of venous thrombosis and recurrent pregnancy loss (RPL) [13–15]. Here, F2 is linked to Venous thrombosis.