Clinical reflections on hereditary thrombophilia

Abstract

To be effective and safe, the coagulation process should induce the formation of a blood clot in the right amount and at the right time. Haemostasis, is the result of interplay between damaged blood vessels, platelets and coagulation factors. The coagulation pathway is a proteolytic cascade, with each enzyme of the pathway present in the plasma as a zymogen (an inactive form), which on activation undergoes proteolytic cleavage to release the active factor from the precursor molecule. The initiation of the coagulation cascade can arise from two major pathways, the Intrinsic and Extrinsic pathways, that finally merge into one common pathway, with thrombin as its final product. Thrombin converts soluble fibrinogen to insoluble fibrin that is essential for clot formation. In similar fashion to other physiological processes, the coagulation cascade involves a number of positive and negative feedback mechanisms that ultimately produces a fine balance between thrombophilic and thrombolytic processes. Any variation in the protein structure of any of the components of the coagulation system can give rise to coagulation disorders.