Hyperhomocysteinemia Protein S Protein C Thrombomodulin Inherited Causes of Blood Clots Abnormalities of clot breakdown (Fibrinolysis) Paroxysmal nocturnal hemoglobinuria FVIII, FIX, FXI, FVII, VWF Prothrombin 20210 mutation Antithrombin Increased levels of natural procoagulants Increased levels of plasminogen activator inhibitor (PAI-1) Other Inherited Causes Decreased levels natural anticoagulants Tissue Factor Pathway Inhibitor (TFPI) Heparin Cofactor II Decreased levels of tissue plasminogen activator (tPA) Plasminogen deficiency Factor V Leiden mutation (APC resistance)