PROS1 and hyperhomocysteinemia: The major genetic trombophilias as prothrombotic conditions include the following: factor V Leiden (FVL) pathologic variant; [17,19,20] G20210 A prothrombin gene pathologic variant; [17,20,21,22]; hyperhomocysteinemia; [23] antithrombin deficiency; [24] and protein C or protein S deficiencies [16,25].