Protein C deficiency is a medical condition characterized by a lack of the protein C molecule in the blood, which is responsible for the proper functioning of the coagulation system. Some synonyms for protein C deficiency include protein C deficiency disorder, congenital protein C deficiency, and inherited protein C deficiency. Additionally, terms like anticoagulant protein C deficiency and thrombophilia may be used to describe the condition. These terms are often used interchangeably to refer to the decreased levels or absence of protein C in the blood. While protein C deficiency is a rare condition, it can lead to severe complications such as blood clots and strokes and must be treated promptly.