[Prevalence of Factor V Leiden and the G20210A mutation of the prothrombin gene in a random group of patients with thrombotic episodes].

Unlabelled: Factor V Leiden and G20210A mutation of the prothrombin gene have been described as risk factors in thrombophilic pathologies. Our objective has been to know the prevalence of these two mutations in a group of patients with thrombophilic pathology and to compare it with its prevalence in a control group of Spanish population.

Patients And Methods: 64 patients were divided in two groups. First, 39 patients with deep venous thrombosis (DVT): 24 with an unique episode of DVT; 11 with more than one episode; 3 with DVT and pulmonary thromboembolism, and one with DVT and more than one episode of cerebral thrombosis. Second, 25 patients with other pathologies, such as pulmonary thromboembolism (9 patients), acute cerebrovascular accident (10 patients) and 6 who came to our Department because there were some carrier in their families. The 20210A allele was analyzed in 37 of the 64 patients. Some of the 64 patients had haematological determinations of the activated protein C resistance (APC resistance). As well, 103 unrelated subjects with unknown thrombotic pathologies were analyzed.

Results: We have found a prevalence of factor V Leiden in the group of patients of 14.1% (9 carriers in 64 patients, all of them in the first group of 39 patients with DVT) versus 1% in the control group (1 carrier in 103 controls). On the other hand, the difference between the prevalence of the 20210A allele was not statistically significant between the group of patients and the control group (2.7% vs 2.9%). In 75% of the patients no haematological results of APC resistance were obtained, generally because they were with anticoagulant treatment, and in 11.1% of the carriers the result of the determination was considered as ambiguous or false negative.

Conclusion: Factor V Leiden is well established as risk factor in the thrombophilic pathology, but more studies are needed to know the meaning of the G20210A mutation of the prothrombin gene.