Analysis of the MMP-9 (C-1562 T) and TIMP-2 (G-418C) gene promoter polymorphisms in patients with chronic periodontitis

Background: Matrix metalloproteinases (MMP)-9 is an important member of the matrix metalloproteinase family. A functional polymorphism has been described in the promoter region of the human MMP-9 gene. A C-to-T base exchange at -1562 creates two different alleles, and the C/T and T/T genotypes promote high activity of the MMP-9 gene promoter, increasing the risk for inflammatory diseases. The metalloproteinase-2 tissue inhibitor (TIMP-2) regulates the activity of MMPs in the extracellular matrix, and a polymorphism at the -418 position of the TIMP-2 gene promoter has been found in a Sp-1 binding site. In this study we have investigated the association between the above-mentioned polymorphisms and chronic periodontitis severity. Methods: Genomic DNA from oral mucosa of 100 subjects was amplified by polymerase chain reaction and analysed by restriction endonuclease digestion. The significance of the differences in observed frequencies of polymorphisms in moderate and severe disease and healthy groups was assessed by chi(2) test (p<0.05). Results: No association was observed between the polymorphism in the promoter region of MMP-9 (p=0.6693) and chronic periodontitis. The analysis of TIMP-2 showed that the G/G genotype was found at a frequency of 99%. Conclusion: The results show that the polymorphism in the promoter region of MMP-9 gene is not associated with chronic periodontitis. The high frequency of GG genotype in the TIMP-2 gene promoter in the population studied did not allow any conclusion regarding its effect on chronic periodontitis.