In our case we have to preclude other conditions that may predispose the patient to recurrent VTE or PTE such as occult malignancies and rheumatologic disorders, for example, anti-phospholipid antibody and inherited thrombophilia—including protein S and C deficiency, factor V Leiden, prothrombin G20210A mutation, and anti-thrombin deficiency. The gene discussed is PROS1; the disease is thrombophilia.