An increase in PAI-1 causes hypofibrinolysis and results in a hypercoagulable state.18 In a single study which measured levels of PAI-1 among FMF patients, significant low levels were found during the attack-free period compared with the acute attack period.13 This observation suggests that during the acute event elevated PAI-1 may increase coagulability. This evidence concerns the gene SERPINE1 and thrombophilia.