Protein C deficiency is a disorder that increases a person's risk to develop abnormal blood clots due to a deficiency of the Protein C, a protein in the body that prevents blood clotting. It may be inherited or acquired. [https://rarediseases.info.nih.gov/diseases/4521/protein-c-deficiency]. The disease is protein c deficiency (EFO_0009316). Also known as: Protein C Deficiency Disease, Protein C deficiency (PCD), Reduced protein C activity, protein C (PC) deficiency.