Gulf States Hemophilia Center iconThe name for a tendency to develop thrombosis (blood clots) due to an abnormality in the blood clotting system. Some common causes of thrombophilia are the Factor V Leiden mutation, the Prothrombin gene mutation, deficiencies of protein C, protein s, or antithrombin III, the lupus anticoagulant, and elevated levels of certain clotting proteins. Thrombosis may also be caused by other medical or surgical conditions and is often treated with anticoagulant medications such as heparin, low-molecular-weight heparin, and Coumadin.