PROS1 and Thromboembolism: Although a wide spectrum of hereditary or acquired causes of thromboembolism such as deficiencies of protein C, protein S, antithrombin III (AT III), Factor V Leiden mutation, prothrombin 20210 mutation, methylene tetrahydrofolate reductase (MTHFR) mutations, high homocystein levels and presence of antiphospholipid antibodies have been reported in IBD patients, still there is no consistent data about most of them [13, 14].