The Association between Polymorphism in the ABCB1 Gene and Opioid Use Disorder in an Egyptian Sample

Abstract

With the advent of the genome-wide association study (GWAS), our understanding of the genetics of substance use disorders has made significant strides forward. Now genetic variants are known to contribute to the development of opioid use disorder (OUD). Polymorphic variation at the ABCB1 gene has been shown to affect the pharmacodynamics and kinetics of various drugs. This study was aimed to evaluate the frequency of the single nucleotide polymorphism (SNP) C3435T (rs1045642) on the ABCB1 gene in opioid (heroin& tramadol) dependent patients. Subjects and Methods: Thirty patients in the ages of 18-50 years who were recently diagnosed with OUD according the ICD-10 Symptom checklist for mental disorders, divided as 15 patients on tramadol and 15 patients on heroin according to the main substance of abuse compared to fifteen healthy individuals as a control group. Each participant of the patient group was subjected to the following tools: ICD-10 Symptom checklist for mental disorders for diagnosis of OUD, Addiction Severity Index (ASI) for rating of severity of the disorder. Both groups were Genotyped using Real time PCR and Taqman Master Mix. Results: A high statistical significant association was found regarding CT (P= 0.04) and CC (P= 0.02) genotypes between case and control groups. We found that the T allele is the favorable and protective allele for susceptibility of opioid addiction in contrast to the C allele. We found that the presence of the ABCB1 gene rs1045642 polymorphism raises the probability to opioid addiction up to 62% (X2 = 14.9; P= 0.002). Regarding presence of the ABCB1 (C/T) gene polymorphism and amenability to which opioid substance; heroin or tramadol, the logistic regression analysis revealed that the presence of ABCB1 rs1045642 polymorphism increases the probability to Tramadol addiction up to 83% in contrast to 27% for Heroin addiction. Conclusion: C3435T polymorphism might have a role in opioid use disorder and likely tramadol more than heroin. Elucidation of these genetic factors is crucial for develop novel therapeutic strategies.