Protein C deficiency is a rare genetic trait that predisposes to thrombotic disease. It was first described in 1981. The disease belongs to a group of genetic disorders know as thrombophilias.
The prevalence of protein C deficiency has been estimated to about 0,2% of the general population.

Protein C deficiency is associated with an increased incidence of venous thromboembolism (relative risk 7), whereas no association with arterial thrombotic disease has been found.

Pathophysiology

---

The main function of protein C is its anticoagulant property as an inhibitor of coagulation factors V and VIII. There are two main types of protein C mutations that lead to protein C deficiency:

• Type I: Quantitative defects of protein C (low production or short protein halflife)
• Type II: Qualitative defects, in which interaction with other molecules is abnormal. Defects in interaction with thrombomodulin, phospholipids, factors V/VIII and others have been described.

Homozygous protein C mutations often causes a severe thrombotic disorder known as purpura fulminans.

Treatment

---

Primary phrophylaxis with aspirin, heparin or warfarin should be considered in known familial cases.
Anticoagulant prophylaxis is given to all who develop a venous clot regardless of underlying cause. Studies have demonstrated an increased risk of recurrent venours thromboembolic events in patients with protein C deficiency. Therefore, long-term anticoagulation therapy with warfarin should be considered in these patients.

Homozygous protein C defect constitutes a potentially life-threatening disease, and warrants the use of supplemental protein C concentrates.