The aim of the study was to investigate the possible role of coagulation factor XIII (FXIII) plasma activity and its gene (F13A1) Val34Leu variant as well as thrombospondin-2 gene (THBS2) T/G 3′UTR and thrombospondin-4 gene (THBS4) Ala387Pro variants in the development of myocardial infarction (MI) in young patients. Here, THBS4 is linked to myocardial infarction.