Evaluation of prodynorphin gene polymorphisms and their association with heroin addiction in a sample of the southeast Iranian population

Genetic factors are supposed to account for about 30-50% of the predisposition to cocaine and heroin addiction. This study aims at investigating the effect of rs2281285, rs2235749, rs910080 and 68bp VNTR polymorphisms of prodynorphin (PDYN) gene on heroin dependence risk in a sample of the southeast Iranian population. This case-control study was done on 216 heroin dependence subjects and 219 healthy subjects. Genomic DNA was extracted from peripheral blood cells using salting out method. Genotyping of PDYN polymorphisms were performed using polymerase chain reaction (PCR) or PCR-RFLP method. The findings showed that PDYN rs910080 T>C variant significantly increased the risk of heroin dependence (OR=7.91, 95%CI=3.36-18.61, P<0.0001, CC vs TT; OR=7.53, 95%CI=3.30-17.16, P<0.0001, CC vs TT+TC; OR=1.75, 95%CI=1.33-2.32, p<0.0001, C vs T). The rs2235749 C>T, rs2281285 A>G and 68bp VNTR variants of PDYN gene were not associated with heroin dependence. Altogether, our results provide an association between rs910080 polymorphism of PDYN gene and risk of heroin dependence in a sample of the southeast Iranian population.