4g/5g Prevalence in 223 Patients with Thrombosis and in 162 Healthy Controls, from the Centre Region of Portugal.

A deletion/insertion polymorphism (4G or 5G) in the promoter of the PAI-1 gene has been suggested to be involved in regulation of the synthesis of the inhibitor, the 4G allele being associated with enhanced gene expression, and therefore related with thrombosis. In the present work we studied the prevalence of 4G/5G polymorphism in 223 unrelated patients with history of objectively confirmed thromboembolism, and in 162 healthy unrelated controls, both groups natural from all centre regions of Portugal. In this normal cohort, the prevalence of 4G/4G is 23%, 4G/5G is 38% and 5G/5G is 39%; in the affected population is, respectively, 47%, 21.5% and 30%, which means that 4G/4G is twice more frequent in the patients with thrombosis. When we relate the age of the first thrombosis episodes in the three groups, we find no significative difference, as the respective media is 36.8; 38.6 and 35.5 years in the 4G/4G, 4G/5G and 5G/5G group, respectively. This data suggest that this polymorphism by itself, even in homozygosity, is not associated with earlier thrombosis. In our patients, we studied the presence of Lupus Anticoagulant, Factor V Leiden, Factor IIG20210A, MTHFR C677T, and also Antithrombin III, Protein S and Protein C levels. We analyse the prevalence of the three mutations in patients with DVP, PTE, ischemic and venous CVA and we only find a significative difference in the 4G/4G group: 46.2% patients with DVP and 48.2% patients with PTE (23% in normal cohort). In conclusion, in the centre region of Portugal, the prevalence of 4G/4G is 23%, 4G/5G is 38% and 5G/5G is 39%; in our cohort of unrelated patients the only significative difference is in the 4G/4G group (47%); this variation maintain in the DVP and PTE group. We did not find difference at the age of the first thrombotic episode, in the three groups.