The Association Between Polymorphisms In Heparin-binding Domain Gene Of Extracellular Superoxide Dismutase And Chronic Obstructive Pulmonary Disease

Objective To investigate the association between polymorphism in EC-SOD heparin-binding domain and chronic obstructive pulmonary disease in Southwest Han Chinese. We analysed the influence of polymorphism on lung function and clinical phenotype in COPD patients. The influence of several factors on lung function severe degrees were synthetically evaluated and the tendency could be determined. Methods The genotypes of 169 patients with COPD and 156 healthy smoking control subjects were tested with mismatch-polymerase chain reaction (mismatch-PCR) followed by restriction fragment length polymorphism (RFLP) for EC-SOD gene. Data were analyzed with SPSS 11.5 software. Ordinal logistic regression model was used in this study for seven variables including genotype age gender smoking index the other influential factors. Results The frequencies of homozygous null-type heterozygote genotypes in EC-SOD heparin-binding domain were 157/169(92.9%) 12/169(7.1%) respectively, no homozygous mutant genotype was detected in COPDgroup. The frequencies of two genotypes showed significant differences between the COPD group and the control group(P<0.05), however there was no difference in the genotypes between lung function groups and two clinical phenotypes(P>0.05).The five variables were statistical significance in ordinal logistic regression model. According to statistical data, it suggested that the risk factors were age patient history male CG genotype and smoking index exceeding 1200 in the development of COPD. The relative risk of CG genotypes was 4.20 times as much as that of CC genotypes. Conclusions Genetic polymorphism in heparin-binding domain of EC-SOD is possible susceptive gene in the development of COPD. CG genotype is one of the risk factors on descending lung function. EC-SOD may be a micro-effective gene, it is likely that the other multiple genes with environmental factors are operating together and the genetic susceptibility may be dependent on the coincidence of several gene polymorphisms acting together in the pathogenesy of COPD.