In our sample, homozygous subjects with T2DM plus the Metabolic Syndrome with the allele 4G had the highest PAI-1 antigen levels when compared with the homozygous 5G without statistical significance (56.7 (48.5–73.7) versus 50.1 (39.1–63.3) ng/mL, p = 0.58). This evidence concerns the gene SERPINE1 and type 2 diabetes mellitus.