Association Between a 50bp Ins/Del Genetic Variation at Promoter of the Superoxide Dismutase-1 (SOD1) and the Risk of Dependency to Opium and Methamphetamine

Superoxide dismutase-1 (SOD1, OMIM: 147450, copper-zinc superoxide dismutase) is one of the major antioxidant enzymes, which plays an important role in clearance of reactive oxygen species. A common genetic polymorphism of 50 bp insertion/deletion (Ins/Del) in the promoter region of the SOD1 has been reported. The purpose of the present study was to investigate the association between this polymorphism and the risk of opium (OD) and methamphetamine (MD) dependency. The present report was consisted of two case-control studies. The first study consisted of 143 OD subjects and 570 healthy controls. The second study consisted of 65 cases with MD and 635 controls. The controls were selected randomly from the healthy blood donors. Genotyping were carried out using PCR based method. Statistical analysis indicated that neither the Ins/Del (OR=1.06, 95% CI: 0.69-1.62, P=0.788) nor the Del/Del (OR=0.57, 95% CI: 0.13-2.55, P=0.464) genotypes were associated with the risk of OD. Although the frequency of the Ins/Del genotype was lower among methamphetamine-dependent persons compared to healthy control subjects, there was no significant association between the Ins/Del polymorphism and the risk of MD (OR=0.82, 95% CI: 0.44-1.53, P=0.547). The present findings demonstrated that the SOD1 50bp Ins/Del polymorphism is not associated with the risk of OD and MD.