| Description: |
Protein C is a natural anticoagulant produced in the liver. It is vitamin K dependent and requires thrombin and thrombomodulin for activation. Activated protein C in the presence of cofactor protein S inactivates factors Va and VIIIa, thereby limiting coagulation. Patients heterozygous for deficiency of protein C or S may exhibit recurrent venous thrombosis at a young age (peak incidence between ages 15 and 40). Heterozygotes also appear to have an increased risk of coumadin-induced skin necrosis. Patients homozygous for protein C deficiency present with generalized microvascular thrombosis in the neonatal period (purpura fulminanas). Normal neonates have lower levels of protein C than adults. Warfarin therapy will result in low protein C levels. See also Thrombosis screen and Activated Protein C Resistance in the Test Directory at www.stanfordlab.com. |
