DNA analysis confirmed the presence of the 1691GA mutation in the factor V gene (factor V Leiden) in all patients with a normalized APC sensitivity ratio of less than 0.70.
Resistance to activated protein C (APC) is a common inherited risk factor for venous thrombosis, which is associated with a mutation in coagulation factor V (factor V Leiden).
Resistance to activated protein C (APC) is a common inherited risk factor for venous thrombosis, which is associated with a mutation in coagulation factor V (factor V Leiden).
The recent discovery of the factor V Leiden mutation as the molecular defect in the large majority of APC-resistant individuals, has drastically changed our view on familial thrombophilia and it has contributed to a better understanding of the interaction of genetic and environmental risk factors.
We determined activated partial-thromboplastin times in the presence and absence of activated protein C and tested for the factor V Leiden mutation in 45 members of seven unrelated consanguineous kindreds in which at least 1 member was homozygous for homocystinuria.
We determined activated partial-thromboplastin times in the presence and absence of activated protein C and tested for the factor V Leiden mutation in 45 members of seven unrelated consanguineous kindreds in which at least 1 member was homozygous for homocystinuria.
Resistance to APC is associated with a single nucleotide change in the factor V gene (G1691-->A) corresponding to a single amino acid substitution in the factor V molecule: Arg506-->Gln (factor V Leiden).
There was considerable overlap in APC ratios in the range of 2 to 3 between subjects with a normal factor V genotype and heterozygotes for factor V Leiden.
Compound heterozygosity for these two defects results in a phenotype similar to a homozygous factor V Leiden state with profound resistance to APC and recurrent thrombosis.
Activated protein C (APC) resistance is a common risk factor for venous thromboembolism and is associated with the replacement of Arg 506 by Gln in the factor V gene (factor V Leiden).
Resistance to activated protein C is a common inherited risk factor for venous thrombosis, which is due to a mutation in coagulation factor V (factor V Leiden mutation).
The heparin cofactor II gene alteration was associated with, in one patient, the factor V Leiden mutation and, in the other, type I protein C deficiency.
A point mutation in coagulation factor V (factor V Leiden) results in resistance to activated protein C and probably represents the most common genetic risk factor for venous thrombosis.
A recently discovered mutation in coagulation factor V (Arg506-->Gln, referred to as factor V Leiden), which results in resistance to activated protein C, is found in approximately one fifth of patients with venous thromboembolism.
The molecular basis of APC resistance is a single-point mutation (arginine506-glutamine) in the gene that encodes for coagulation factor V. This mutation results in a factor V molecule (factor V(Leiden)) that is less effectively downregulated by APC than is normal factor V. The gold standard for the detection of this defect is DNA analysis.
The molecular basis of APC resistance is a single-point mutation (arginine506-glutamine) in the gene that encodes for coagulation factor V. This mutation results in a factor V molecule (factor V(Leiden)) that is less effectively downregulated by APC than is normal factor V. The gold standard for the detection of this defect is DNA analysis.
Women who used third-generation monophasic OC were significantly less sensitive to APC than women using second-generation OC (P<0.001) and had APC-sr that did not significantly differ from heterozygous female carriers of factor V(Leiden) who did not use OC.