Effect of rs4680 (Val158Met) Polymorphism of the COMT Gene on Opioid Addiction in an Iranian Population: A Case-Control Study

Drug addiction is a serious neurological disorder that is significantly associated with mortality and morbidity. It is accompanied by social, economic, and health problems for both the individual and the whole society. Genes playing a role in the catabolism of dopamine (DA), such as catechol-O-methyltransferase (COMT), seem to be plausible candidate genes for drug dependence. This study aimed to investigate the effect of rs4680 (Val158Met) polymorphism of the COMT gene on opioid addiction (OA) in the whole samples and male/female subsamples of an Iranian population. The current case-control study was conducted with 96 cases (87 men and nine women with OA) and 142 controls (117 men and 25 women). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to genotype the samples. Our results showed no significant association between the COMT rs4680 gene polymorphism and OA in the total population. In addition, we found no notable correlation between rs4880 and OA in male and female subsamples. In conclusion, there was no correlation between the rs4680 polymorphism of the COMT gene and opioid addiction. The conflicting results in studies with different ethnicities and sample sizes suggest that additional studies are needed to investigate the Val158Met polymorphism correlation with other variants of the COMT gene in larger populations and in both genders with opioid and other addictions