Polymorphic Variants in SOD-1 and Catalase Genes and its Relation toward Modulating the Risk in COPD

Abstract

Chronic obstructive pulmonary disease (COPD)'s etiology has been linked to increased oxidative stress. This study looked at the cytosine to thymidine transition at nucleotide -262 (-262 C>T) of the catalase gene, the 50-bps insertion-deletion polymorphism at 1684 bp upstream of the ATG start codon of Copper-Zinc superoxide dismutase (Cu Zn-SOD), and their relation towards modulation the risk of COPD. The participants were healthy controls and stable COPD patients (n=200, for both cases and controls), matched for their average age. The catalase gene at -262 C>T and Cu Zn-SOD 50 bp Ins/Del were genotyped, and statistical analysis was performed to check for the risk factors associated with the disease. Del/ Del genotype was found in 5.5% of the subjects, and T/T was found in 10.0% of the subjects, which were significantly higher than controls, 1.0%, and 2.5% in both cases, respectively. A significant association of risk factors was for both genes, suggesting their association in modulating the risk of the disease. In the case of Cu Zn-SOD, a significant six-fold increase was observed in the co-dominant model for the Del/Del genotype (AOR=6.56, 95% CI=1.35-31.88, p=0.0197). While in the case of catalase, a significant approximate increase of five-folds was observed in the co-dominant model for T/T genotype (AOR=4.62, 95% CI=1.63-13.11, p=0.003). A significant association of risk was also found to be linked with the patients' CAT score, age, and GOLD group. A combinational study of the polymorphism involving both genes obtained a significant increase in the associated risk with the increased alternations, where a total of three alterations in both the genes combined were linked with a more than seven-fold risk in the patients (AOR=7.71, 95%CI=1.58-37.5, p=0.0114).