Activated Protein C Resistance
Activated protein C resistance (APCR) is a hypercoagulability (an increased tendency of the blood to clot) characterized by a lack of a response to activated protein C (APC), which normally helps prevent blood from clotting excessively. This results in an increased risk of venous thrombosis (blood clots in veins), which resulting in medical conditions such as deep vein thrombosis (usually in the leg) and pulmonary embolism (in the lung, which can cause death).
Presentation
Associated conditions
An estimated 64 percent of patients with venous thromboembolism may have activated protein C resistance.
Genetics
The disorder can be acquired or inherited, the hereditary form having an autosomal dominant inheritance pattern.
Pathophysiology
Activated protein C (with protein S as a cofactor) degrades Factor Va and Factor VIIIa. Activated protein C resistance is the inability of protein C to cleave Factor Va and/or Factor VIIIa, which allows for longer duration of thrombin generation and may lead to a hypercoagulable state. This may be hereditary or acquired. The best known and most common hereditary form is Factor V Leiden. Acquired forms occur in the presence of elevated Factor VIII concentrations.
Diagnosis
"APC(Activated protein C) ratio: To diagnose functional assays | PCR(Polymerase chain reaction)/ Restriction enzyme analysis: To detect the specific genetic anomaly responsible for FVL(factor V Leiden) "