Antioxidant Gene Polymorphisms in Temporomandibular Disorder Patients Compared to Controls

Objectives: To investigate the distribution of single nucleotide polymorphisms (SNPs) of genes glutathione peroxidase 1 (GPX1), superoxide dismutase 2 (SOD2), and catalase (CAT) in temporomandibular disorders (TMD) patients in comparison with healthy controls, and to explore whether psychosomatic characteristics and oral behaviors (OB) may be influenced by SNPs in these genes.
Methods: Eighty-five TMD patients (diagnosed with DC/TMD) and 85 controls were recruited. DNA from buccal mucosal swabs was analyzed for SNPs in GPX1 (rs1050450), SOD2 (rs4880), CAT (rs1001179). Participants completed questionnaires for anxiety (Generalized Anxiety Disorder-7, score: 0-21), depression (Patients Health Questionnaire-9, score: 0-27), hypervigilance (The Brief Hypervigilance Scale, score: 0-20), and waking-state (score: 0-76) / sleep-related (score: 0-8) oral behaviors (Oral Behaviors Checklist). Chi-Square Test and Mann-Whitney U Test were used for statistical analysis. The assessment was performed according to dominant and recessive genetic models. In both models, the minor allele represented the risk allele.
Results: No differences in genotype distribution were found between TMD patients and controls in dominant and recessive models (p>0.05). Analysis of psychosomatic and behavioral characteristics according to genotype revealed that TMD patients with AA genotype of rs1050450 (minor allele homozygous) reported significantly more waking-state OB compared to AA+AG genotypes (score: 30 vs. 23, p=0.019). TMD patients with the AA genotype of rs4880 (dominant homozygous) reported significantly higher hypervigilance scores compared to GG+AG genotypes (6.1 vs. 3.2, p=0.0001). TMD patients with the CC genotype of rs1001179 (dominant homozygous) reported significantly higher depression scores compared to TT+TC genotypes (7.1 vs. 4.1, p=0.002). In the control group, examined characteristics were not influenced by genotype.
Conclusions: These findings suggest that some TMD patients may be genetically predisposed to specific psychosomatic symptoms and OB. Further research is needed to better understand the underlying mechanisms of gene-behavior associations in TMD.