SERPINE1 and venous thromboembolism: Evidence is conflicting regarding the association of the factor XIII Val34Leu polymorphism with risk of venous thromboembolism [79], it is noteworthy that Kohler et al. [80] described higher concentrations of PAI-1 and an increased frequency of the PAI-1 4G/4G genotype in patients with the FXIII 34Leu genotype and myocardial infarction (MI), suggesting that impaired fibrinolysis negates the postulated protective effect of the FXIII 34Leu genotype.