mRNA Expression and genetic polymorphisms affecting DRD3 (rs6280) and HTR2A (rs6313) in bruxism

Abstract

Background: Bruxism, a condition characterized by the involuntary grinding or clenching of teeth, is influenced by a combination of genetic, psychological, and environmental factors. This study aimed to evaluate the influence of genetic polymorphisms affecting DRD3 (rs6280) and HTR2A (rs6313) on bruxism and to investigate the expression of HTR2A and DRD3 to elucidate their biological significance in bruxism. Methods: A cross-sectional study was conducted with 169 participants, including 87 controls and 82 bruxism cases. Genotyping for DRD3 (25G>A; rs6280) and HTR2A (102C>T; rs6313) was performed using PCR-RFLP analysis. Total RNA was extracted to assess changes in the expression of HTR2A and DRD3. Results: The study found a significant association between bruxism and the rs6313 polymorphism of the HTR2A gene (p= 0.004; OR= 1.89 [1.23-2.92]), with the T allele associated with a increased risk of bruxism. Additionally, increased HTR2A mRNA expression was observed in individuals with bruxism. While no statistically significant differences were found in the distribution of DRD3 rs6280 genotypes between control and case groups, the presence of the C allele may be associated with a higher susceptibility to developing sleep bruxism. Furthermore, decreased DRD3 mRNA expression was observed in individuals with bruxism. Conclusions: The findings suggest a significant association between bruxism and the rs6313 polymorphism of the HTR2A gene. Additionally, increased HTR2A and decreased DRD3 mRNA expression were observed in individuals with bruxism, indicating the complex interplay between genetic factors and bruxism etiology. Clinical Significance: This study elucidates the genetic basis of bruxism, indicating a potential role of serotonin and dopamine signaling in its pathogenesis. Understanding genetic predisposition could aid in early detection, risk assessment, and targeted treatment development. Clinicaltrials.gov registration number NCT06457646, 8th June 2024.