The prevalence of Factor V Leiden as a risk factor for venous thromboembolism in the population of North-Western Greece

Background. Many predisposing factors have been associated with the develop ment of venous thromboembolism. Recently, Factor V Leiden has been describe d as a common genetic risk factor. The geographic distribution of this gene tic abnormality in the general population greatly varies. The prevalence of the Factor V Leiden mutation in Europe is high, particularly in Greece, wh ere according to some authors it is especially high. The purpose of this st udy was to estimate the prevalence of the Factor V Leiden mutation in patie nts presenting with at least one episode of venous thromboembolism and to c ompare it with that of the general population. Methods. Blood samples were drawn from 388 subjects. 240 healthy blood dono rs (controls) and 148 unselected patients with a history of one or more epi sodes of venous thrombosis. DNA analysis was performed using the polymerase chain reaction to amplify the factor V gene exon 10, and to detect the Fac tor V Leiden point mutation. Results. DNA analysis revealed Factor V Leiden mutations in eight (3.3%) co ntrol subjects (seven heterozygous and one homozygous) and in twenty-four ( 16.2%) patients, (twenty-two heterozygous and two homozygous). The differen ce between the two groups is statistically significant (p<0.0001; <chi>(2) test). Conclusions. The prevalence of the Factor V Leiden mutation in the general population of North-Western Greece is 3.3%, which is within the same range as that reported for other European countries. The Factor V Leiden mutation is one of the most important predisposing genetic factors in the developme nt of venous thrombosis and was present in 16.2% of our patients.