Coagulation factor V Leiden mutation in sudden fatal pulmonary embolism and in a general northern European population sample

The R506Q point mutation in the gene coding for coagulation factor V (Leiden mutation) is the major underlying defect in resistance to activated protein C (APC), which predisposes to venous thrombosis. The risk of deep vein thrombosis is clearly elevated in carriers of the mutation, but the risk for pulmonary embolism has not been demonstrated to be as high. The aim of our study was to determine the frequency of the Leiden mutation in an autopsy series of sudden fatal pulmonary embolism cases. PCR and subsequent restriction enzyme digestion were applied for genotyping 164 cases of pulmonary embolism. According to our data, the allele frequency of the Leiden mutation is not higher in sudden fatal pulmonary embolism cases (0.8%, 95% CI 0-1.9%) than in the general Finnish population (1.5%, 95% CI 0-3.3%). In addition to the 97 Finns, we determined the frequency of the Leiden mutation in 255 individuals from the neighbouring populations (Saami, Komi, and Karelians from Russia and Estonians), and found the Saami to have the highest frequency of the Leiden mutation (6.3%, 95% CI 3.2-9.2) in the general northern European population sample studied here.