Association between the -1562 C/T polymorphism of matrix metalloproteinase-9 gene and lumbar disc disease in the young adult population in North China.

Many studies have demonstrated that matrix metalloproteinase-9(MMP-9) is involved in the development of lumbar disc disease (LDD). The expression and activity of MMP-9 are significantly enhanced in degenerative discs. The polymorphism -1562C/T in the promoter region of MMP-9 gene alters the transcriptional activity of this gene. In this study we assessed the relationship between the -1562C/T polymorphism of matrix metalloproteinase-9 gene and the extent of degenerative disc disease in the young adult population in North China. Genotypes were defined by polymerase chain reaction and direct DNA sequencing in 408 young patients with LDD and 451 control subjects. The resulting genotypes were correlated with the presence of lumbar disc degeneration on MRI. The frequency of the MMP-9 -1562T genotype in patients with LDD was significantly higher than in healthy controls. Compared with CC genotype, subjects with the CT/TT genotype had a higher risk to develop LDD (odds ratio 2.14; 95% confidence interval 1.55-2.96). Moreover, an association was found between this genotype and more severe grades of disc degeneration observed on magnetic resonance imaging scan. These results indicated that the -1562C/T polymorphism of the MMP-9 gene is associated with a high risk of degenerative disc disease in the young adult population in North China.