Osmosis video - Protein S deficiency

Protein S deficiency is a disorder associated with an increased risk of venous thrombosis. Protein S, a vitamin K-dependent natural anticoagulant, acts as a nonenzymatic cofactor to activate protein C in the proteolytic degradation of factor Va and factor VIIIa. Decreased levels or impaired function of protein S leads to decreased degradation of factor Va and factor VIIIa and an increased risk of blood clots, which can cause complications like deep vein thrombosis (DVT) and pulmonary embolism (PE). Treatment includes anticoagulant medications and avoiding drugs that predispose to hypercoagulability, such as oral contraceptives.