F13B and venous thromboembolism: At a 2.8-year poststroke follow up for mortality, FXIIIB and FXIIIA have been found to be present at significantly higher levels in survivors compared with those that had died.26 One particular polymorphism, FXIIIVal34Leu, has been reported to provide a protective effect against venous thromboembolism and myocardial infarction in Caucasians (in the absence of insulin resistance).27,28 The same polymorphism conveys no protective effect in South Asians, known to have higher levels of insulin resistance.