PROS1 and hepatic veno-occlusive disease: In an inherited thrombophilia, hypercoagulability caused by the deficiency of protein C and protein S predisposes an individual to increased risk of thromboembolism (TE) that could herald as a venous thromboemboilsm (VTE) in the leg, pulmonary embolism (PE), stroke, or Budd-Chiari syndrome.