The specific aims were: 1) to screen genomic DNA from patients with VTE for mutations within (candidate) genes encoding for prothrombin, thrombomodulin, tissue factor pathway inhibitor, tissue factor, factor VII, and factor X, and to determine if the mutation predicted a change in either protein expression or structure; 2) in population-based case-control studies, a) to test the hypothesis that such a mutation was associated with VTE, estimate the strength of the association, and determine the independence of the association after controlling for other environmental risk factors and coagulation abnormalities, including interactions, and b) to test the hypothesis that a mutation was associated with death and autopsy; 3) to estimate the attributable risk for VTE associated with each significant mutation, both individually and for all independently significant mutations collectively while controlling for other environmental risk factors and coagulation abnormalities; and 4) in a population-based retrospective cohort study, to estimate the time-to-VTE recurrence and to test the hypothesis that each significant mutation was an independent predictor of VTE recurrence after controlling for other environmental predictors and coagulation abnormalities, including interactions.