PROS1 and antiphospholipid syndrome: Primary states include conditions such as factor V Leiden, prothrombin gene mutation, and deficiencies in antithrombin, protein C, or protein S. Secondary states include atrial fibrillation, malignancy, disseminated intravascular coagulation, antiphospholipid syndrome, cardiomyopathy, nephrotic syndrome, high estrogen levels, sickle cell anemia, and smoking.