It has been indicated that the most common cause of the hypercoagulable state is the antiphospholipid syndrome, followed by factor V Leiden (1691 G/A) mutation, prothrombin gene G20210A mutation, elevated factor VIII, and hyperhomocysteinemia, Less common disorders are deficiencies in antithrombin, protein C, or protein S [5]. Here, PROS1 is linked to antiphospholipid syndrome.