Objective To determine whether the matrix metalloproteinase-9 (MMP-9) c 1562C>T polymorphism has an effect on the plasma MMP-9 levels and the macroangiopathic complications in type 2 diabetes mellitus (T2DM) Methods The genotypes and allelic frequencies of the MMP-9 c 1562C>T were examined with polymerase chain reaction and restriction fragment length polymorphism in 320 patients with T2DM and 160 unrelated healthy subjects. The plasma concentrations of MMP-9 were determined in all subjects Results The mean plasma concentrations of MMP-9 of patients with T2DM were significantly higher than that of controls and the plasma levels of MMP-9 were higher in diabetic patients with macroangiopathy than in patients without macroangiopathy (P < 0.05). The genotype (CC, CT, and TT) distribution of c 1562C>T polymorphism of the MMP-9 gene was 60 0%. 31 3%, and 8.8% in diabetic patients with macroangiopathy, 76 3%, 21.3%. and 2 5% in patients without macroangiopathy, and 77 5%, 21 3%, 1 3% in controls, respectively, a significant difference was found between diabetic patients with and without macroangiopathy (P < 0 05) The frequency of the allele T was higher in patients with macroangiopathy than in patients without macroangicipathy (24 4% vs 13.1%. P < 0 05). Moreover, the plasma MMP-9 levels were markedly higher in patients with TT genotype than those with CC or CT genotype in patients with macroangiopathy (P < 0 05) Conclusion: The MMP-9 c 1562C>T gene polymorphism associated with a predisposition to increased plasma MMP-9 levels could constitute a useful predictive rnarker for diabetic macroangicipathy (C) 2009 Elsevier Inc All rights reserved