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 μ-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(®) 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, Fisher's 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.