Mu opioid receptor (OPRM1) as a predictor of treatment outcome in opiate-dependent individuals of Arab descent

Background: A number of research studies on the genetics of opiate dependence have focused on the mu-opioid receptor (OPRM1), which is a primary target for opiates. This study aims to identify genetic polymorphisms within the OPRM1 gene involved in response to the biopsychosocial treatment in opiate-dependent individuals of Arab descent. Methods: Unrelated Jordanian Nationals of Arab descent (N = 183) with opiate dependence were selected for this study. These individuals, all males, met the DSM-IV criteria for opiate dependence and were undergoing a voluntary 8-week treatment program at a Jordanian Drug Rehabilitation Centre. All individuals were genotyped for 22 single nucleotide polymorphisms (SNPs) within the OPRM1 gene using the Sequenom MassARRAY (R) system (iPLEX GOLD). Statistical analyses were carried out using the R package. Results: Patients receiving biopsychosocial treatment showed that there was a significant difference in their OPRM1 SNPs genotyping distribution between good, moderate, and poor responders to the treatment at two sites (rs6912029 [G-172T], and rs12205732 [G-1510A], P < 0.05, Fishers exact test). Conclusion: This study is the first report of an association between the OPRM1 G-172T and G-1510A polymorphisms and treatment response for opiate dependence. Specifically, this study demonstrated that the OPRM1 GG-172 and GG-1510 genotypes were more frequent among patients who were nonresponders to the biopsychosocial treatment. However, further pharmacogenetic studies in a larger cohort of opiate-dependent patients of Arab descent are needed to confirm these findings and identify individuals with increased chance of relapse.