Genetic polymorphism in matrix metalloproteinase-9 and the susceptibility to chronic obstructive pulmonary disease in Han population of south China

Background There are many candidate genes for chronic obstructive pulmonary disease (COPD). Matrix metalloproteinase-9 ( MMP-9) plays an essential role in tissue remodeling and repair associated with development of COPD. In this study we investigated the correlation between MMP-9 gene polymorphism and COPD susceptibility in the Han population of South China. Methods We examined the frequency of polymorphic genotypes of the MMP-9 promoter ( -1562C/T) in 100 COPD patients and 98 healthy smokers by restriction fragment length polymorphism. Results The frequencies of polymorphic genotypes in promoters of MMP-9 were C/C 86%, C/T 14% in COPD group; and C/C 98%, C/T 2% in the control group. There were significant differences between the two groups ( P < 0.01). The allele frequencies were also significantly different between the COPD group and the control group (C allele frequency: 93% vs 99%, T allele frequency: 7% vs 1 %, P < 0.05 respectively). Conclusion The genetic polymorphism in promoters of MMP-9 gene is associated with the susceptibility to COPD in the Han population of South China.