FV R506Q Mutation and Elevated Lipoprotein (a): A Possible Link to the Plasminogen Activator Inhibitor-1 (PAI-1) 4G/4G Genotype?

To evaluate the role of plasminogen activator inhibitor-1 (PAI-1) 4G/4G genotype or elevated lipoprotein (a) (Lp(a)) in subjects with the Factor V (FV) R506Q mutation, 56 children with an early onset of thromboembolism, 46 first-degree relatives and 99 healthy controls were investigated. PAI-14G/5G polymorphism, FV R506Q mutation, protein C, protein S, antithrombin (AT) and Lp(a) were determined. The heterozygous FV R506Q mutation was found in combination with the PAI-14G/4G genotype in 61% of patients, 62% of relatives, and 33% of the controls. In addition, the FV R506Q mutation was found with elevated Lp(a) (23%) and antithrombin deficiency (15%). We did not find a heterozygous FV R506Q mutation without a further prothrombotic risk factor in symptomatic children with thromboembolism. In conclusion, patients and first-degree family members carrying the FV R506Q mutation showed more often the PAI-14G/4G genotype or elevated Lp(a) compared with the controls. With respect to the small number of subjects investigated these findings have to be interpreted as a preliminary result.