Background: Many predisposing factors have been associated with the development of venous thromboembolism. Recently, Factor V Leiden has been described as a common genetic risk factor. The geographic distribution of this genetic abnormality in the general population greatly varies. The prevalence of the Factor V Leiden mutation in Europe is high, particularly in Greece, where according to some authors it is especially high. The purpose of this study was to estimate the prevalence of the Factor V Leiden mutation in patients presenting with at least one episode of venous thromboembolism and to compare it with that of the general population.
Methods: Blood samples were drawn from 388 subjects. 240 healthy blood donors (controls) and 148 unselected patients with a history of one or more episodes of venous thrombosis. DNA analysis was performed using the polymerase chain reaction to amplify the factor V gene exon 10, and to detect the Factor V Leiden point mutation.
Results: DNA analysis revealed Factor V Leiden mutations in eight (3.3%) control subjects (seven heterozygous and one homozygous) and in twenty-four (16.2%) patients, (twenty-two heterozygous and two homozygous). The difference between the two groups is statistically significant (p<0.0001; chi2 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 development of venous thrombosis and was present in 16.2% of our patients.