Four members of an Italian family (two with histories of venous thromboembolism) had a qualitative defect of antithrombin III reflected by normal antigen concentrations and half-normal antithrombin activity with or without heparin.
The major clinical manifestations of ATIII deficiency are young age at onset, idiopathic thrombosis, family history, and recurrent venous thromboembolism.
The incidence of these hereditary disorders in our 204 patients (106 males and 98 females) with venous thromboembolism were 4% (three cases deficient in PC, three in PS, two in PLG, and one patient in AT III).Their families were studied.
Thus, factor V Leiden was associated with a fourfold to fivefold increase in risk of recurrent VTE (crude relative risk, 4.1; P = .04; age- and smoking-adjusted relative risk, 4.7; P = .047).
We have analysed 3380 chromosomes (1690 unrelated individuals) from twenty-four populations for the presence of factor V Leiden, an important risk factor in venous thromboembolism.
To assess their tendencies to venous thrombosis, we compared the median age of first venous thromboembolism in patients with factor V Leiden or protein C deficiency, who were identified either within unselected consecutive cases with a first deep venous thrombosis derived from a population-based case-control study, or identified by selection of patients with a deep venous thrombosis, who were referred for thrombophilIa work-up.
Therefore, more data are needed from various populations of patients with venous thromboembolism to help decide which patients will benefit from screening for resistance to APC.
We investigated the risk of recurrence of venous thromboembolism in APC resistant patients heterozygous for FV Leiden and compared these patient groups with a group of patients, who had a history of venous thromboembolism, but had neither APC resistance nor the FV Leiden mutation.
Here we have analysed 125 consecutive patients with incidental or recurrent venous thromboembolism for the presence of mutations at the cleavage sites for APC at amino acid positions Arg336 and Arg562 of factor VIII.
It is remarkable that certain patients with heterozygous protein C (PC) deficiency manifest venous thromboembolism (VTE), whereas others, particularly those belonging to families with homozygous PC deficiency, remain asymptomatic.
Here we have analysed 125 consecutive patients with incidental or recurrent venous thromboembolism for the presence of mutations at the cleavage sites for APC at amino acid positions Arg336 and Arg562 of factor VIII.
The odds ratio for the FII 20210G/A mutation in 504 patients with venous thromboembolism compared to controls was 2.0 (95% CI 1.0-4.0) and, for factor V Leiden, 5.8 (95% CI 3.3-10.3).
The aim of this study was to compare the prevalence of the prothrombin 20210A allele in control subjects and in subjects with recognised thrombophilia and to establish whether the additional inheritance of the PT 20210A allele is associated with an increased risk of venous thromboembolism.
Further clinical trials are also required to determine if a longer course of treatment is indicated for subgroups of patients based on clinical characteristics and laboratory features (such as those with idiopathic thrombosis versus postoperative thrombosis, and those with or without identifiable molecular markers of a high risk of recurrent venous thromboembolism such as the factor V Leiden gene mutation).
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 HR2 haplotype was associated with significantly lower APC ratios both in patients with venous thromboembolism and in age- and sex-matched controls.