Protein C eficiency 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% to 0.5% of the general population. Protein C deficiency is associated with an increased incidence of venous thromboembolism (relative risk 8-10), whereas no association with arterial thrombotic disease has been found.