Polymorphism of Gene OPRM A118G and COMT G158A and Pain Sensitivity of the Minangkabau Ethnic, Indonesia

Background: Opioid is considered analgesic that has been used for thousands of years because of their effectiveness in treating pain during surgery. The opioid receptor encoded by the OPRM1 gene has several variants, including 118 A>G (adenine to guanine) that lead to different pain sensitivity. Other factors that also contribute to pain sensitivity are endogen opioids which are encoded by the COMT gene, which commonly has 168 G>A (guanine to adenine) polymorphism. This study aims to analyze the association between OPRM1 A118G and COMT G158A gene polymorphisms with pain sensitivity in the Minangkabau ethnic group. Materials and Methods: This cross-sectional study took samples by consecutive sampling from 60 Minangkabau dan 30 non-Minangkabau patients that undergo general anesthesia in Dr. M Djamil Hospital and Andalas University Hospital, Padang, West Sumatra, Indonesia from early November 2021 until the end of January 2022. The association between OPRM1 A118G and COMT G158A gene polymorphisms with ethnicity and pain sensitivity was analyzed by Kruskal Wallis and Chi-square formulas respectively. Results: We found there were no significant differences between OPRM1 A118G and COMT G158A gene polymorphisms in Minangkabau and non-Minangkabau ethnics (p=0.36 and p=0.53 respectively). The Difference between pain sensitivity before and after surgery in OPRM1 A118G and COMT G158 gene polymorphisms are not significant in Minangkabau ethnic (p>0.05). Conclusion: OPRM1 A118G and COMT G158A gene polymorphisms had no significant association with pain sensitivity in Minangkabau ethnic.