Association Study of Opioid Receptor Delta-Type 1 (OPRD1) Gene Variants with Nicotine Dependence in an Iranian Population.

Twins studies indicate that many individual factors are associated with genetic polymorphisms in tobacco use, dependence vulnerability, and the ability to quit smoking. Opioid receptor delta-type 1 (OPRD1) is one of the most important genes in the opioid pathway. Therefore, the current study aimed to investigate the association of variants located in the intron 1 of the OPRD1 gene, including rs2236857, rs2236855, and rs760589, with susceptibility to nicotine dependence among northern Iranians. DNA of 426 individuals, including 224 smokers and 202 healthy people, were extracted with the salting-out standard technique, qualified with Agarose gel, then quantified with Nanodrop, and finally genotyped by Amplification Refractory Mutation System (ARMS) PCR. All statistical analyses were performed by SNPAlyze version 8.1 and SPSS version 20. Results revealed no significant association of all three studied variants with the susceptibility to nicotine dependence in any models of inheritance. However, there were five haplotypes with an overall frequency higher than 0.05; no significant impact of any of them on nicotine dependence was observed. Altogether, rs2236857, rs2236855, and rs760589 were not associated with nicotine dependence among northern Iranians.