Single nucleotide polymorphisms in genes of dopaminergic pathways are associated with bruxism

Objectives: This research aimed to evaluate the frequency of single nucleotide polymorphisms (SNPs) in dopaminergic pathway genes (DRD1, DRD2, DRD3, DRD4, DRD5, and MAOB) in patients undergoing bruxism treatment and controls.

Subjects and methods: Patients submitted to bruxism treatment were classified in awake bruxism (61 patients), sleep bruxism (26 patients), and awake-sleep bruxism (43 patients). Control group included 59 patients. Association between circadian manifestations of bruxism and SNPs was investigated using Fisher's exact test, chi-squared test, and calculating the odds ratios and their respective 95% confidence intervals.

Results: The G allele of DRD2 rs1800497 SNP was associated with a significant risk reduction of awake-sleep bruxism (p = 0.041), while the C allele of DRD3 rs6280 SNP was associated with increased risk of sleep bruxism (p = 0.02), and the C allele of DRD5 rs6283 SNP was associated with decreased risk of awake bruxism (p = 0.01).

Conclusions: To our knowledge, this is the first report exploring the contribution of genetic variants in dopaminergic pathways to bruxism development, considering all circadian manifestations. Our findings indicate a possible genetic influence in the etiology of awake, sleep, and awake-sleep bruxism. Therefore, further research is needed to increase the current understanding of bruxism physiopathology.