Protein C deficiency is a disorder of blood clotting. People with this condition have an increased risk of developing abnormal blood clots.
Individuals with mild protein C deficiency are at risk of a type of clot called a deep vein thrombosis (DVT) that occurs in the deep veins of the arms or legs. If a DVT travels through the bloodstream and lodges in the lungs, it can cause a life-threatening clot known as a pulmonary embolism (PE). Other factors can raise the risk of abnormal blood clots in people with mild protein C deficiency. These factors include increasing age, surgery, immobility, or pregnancy. The combination of protein C deficiency and other inherited disorders of blood clotting can also influence risk. Most people with mild protein C deficiency never develop abnormal blood clots, however.