Subsequently, it was demonstrated that a mutation in a single clotting factor, FV, showed resistance to activated protein C. Since activated protein C is supposed to downregulate aFV and aFVIII, their persistence in the circulation gives origin to a hypercoagulable state.
Conclusions FVBonn induces hypercoagulability via a combination of increased activation/procoagulant activity, decreased susceptibility to APC-mediated inactivation, and slightly reduced APC cofactor activity.
Thrombin generation assays sensitive to the APC- and TFPI-cofactor activities of protein S revealed similar hypercoagulable states in type I and type III protein S-deficient plasma.
Thrombin generation assays sensitive to the activated protein C- and tissue factor pathway inhibitor-cofactor activities of protein S revealed similar hypercoagulable states in type I and type III protein S-deficient plasma.
One of the most common hereditary thrombophilias is the factor V Leiden mutation, which is identified with a screening assay for activated protein C (APC) resistance and confirmed by DNA analysis.
Activated protein C (aPC) resistance is a recognized hypercoagulable phenotype that is associated with increased risk for thrombosis in multiple clinical settings.
Recently, a poor anticoagulant response to activated protein C (APC), due to a mutation of factor V (FV Leiden), has been identified as the most frequent hereditary disorder associated with venous thrombophilia.
This mutation, defined as factor VLEIDEN, results in activated protein C (APC) resistance and is the most common genetic risk factor for familial thrombophilia.
Complexes between activated protein C and protein C inhibitor measured with a new method: comparison of performance with other markers of hypercoagulability in the diagnosis of deep vein thrombosis.
Factor V is an important blood coagulation factor, the procoagulatory activity of which is inhibited by activated protein C. The factor V Leiden mutation is due to a single base-pair change (G1691A), which alters the initial cleavage site for activated protein C. The impaired degradation of factor V by activated protein C yields a hypercoagulable state that confers a lifelong increased risk of thrombosis in heterozygous and homozygous individuals.
A resistance to the anticoagulant activity of activated protein C (APC), most frequently due to a point mutation in the Factor V gene (the Leiden mutation), represents the most common genetic cause of thrombophilia.
The cause of the BCS still being unknown, in October 1996 we performed extensive laboratory investigations concerning states of thrombophilia and found moderately elevated IgG anticardiolipin antibodies (19.7 U/ml) and a resistance against activated protein C caused by heterozygosity for a point mutation of the factor V gene (1691G-->A; factor V Leiden).
We compare results of factor V DNA analysis with three different clotting-based assays designed to detect activated protein C (APC) resistance (APCR), using samples from 958 patients undergoing assessment for thrombophilia.
In an attempt to investigate the prevalence of hypercoagulable states in patients with venous leg ulcers, we performed a prospective case-control study for the presence of coagulation defects in such patients, including resistance to activated protein C (APC), factor V Leiden mutation and a newly described mutation in factor II.
To evaluate the role of inherited thrombophilia in the development of central venous line (CVL)-related thrombosis, the following parameters were determined in 77 pediatric-oncologic patients with CVL: activated protein C (APC)-ratio, factor V (FV) G1691A and prothrombin G20210A mutation, protein C, protein S, antithrombin, coagulation factor XII, lipoprotein (a) and homocysteine.
The factor V Leiden gene mutation decreases the sensitivity of factor V to the anticoagulant activity of activated protein C, and has been shown to be the most common inherited defect associated with a hypercoagulable state.