Mu Opioid Receptor Gene: New Point Mutations in Opioid Addicts

Association between single-nucleotide polymorphisms (SNPs) in mu opioid receptor gene and drug addiction has been shown in various studies. Here, we have evaluated the existence of polymorphisms in exon 3 of this gene in Iranian population and investigated the possible association between these mutations and opioid addiction. 79 opioid-dependent subjects (55 males, 24 females) and 134 non-addict or control individuals (74 males, 60 females) participated in the study. Genomic DNA was extracted from volunteers’ peripheral blood and exon 3 of the mu opioid receptor gene was amplified by polymerase chain reaction (PCR) whose products were then sequenced. Three different heterozygote polymorphisms were observed in 3 male individuals: 759T>C and 877G>A mutations were found in 2 control volunteers and 1043G>C substitution was observed in an opioid-addicted subject. Association between genotype and opioid addiction for each mutation was not statistically significant. It seems that the sample size used in our study is not enough to confirm or reject any association between 759T>C, 877G>A and 1043G>C substitutions in exon 3 of the mu opioid receptor gene and opioid addiction susceptibility in Iranian population.