What Is Activated Protein C Resistance?

Activated protein C resistance (APCR) is the most common pathological factor of familial thrombosis. The point mutation of the coagulation factor V (F) gene caused the replacement of arginine at position 506 of the F molecule by glutamine is the molecular mechanism that causes APCR. APCR is closely related to venous thrombosis because mutations in the FV gene resist the degradation of activated protein C (APC). F gene mutations are heterozygous and homozygous. APCR can increase the risk of thrombosis in patients for life. Heterozygous can increase the risk of thrombosis by 5 to 10 times, and homozygous can increase the risk of thrombosis by 50 to 100 times. In addition, lupus, anti-cardiac phosphoantibodies, pregnancy, tumor and infection after chemotherapy, oral contraceptives, etc. are also the causes of APCR, but have nothing to do with F gene mutation. The APC-APTT method is commonly used as a screening APCR method. F activator and partial thromboplastin are added to the tested plasma to start the coagulation pathway, and then APC is added to determine the APTT extension time.