Genetic Polymorphisms are Associated With Temporomandibular Disorders in Adolescents

Objectives: The aim of this study was to determine the presence of association between anxiety, temporomandibular disorder (TMD) and genetic polymorphisms in 5HTT and COMT.
Methods: For this study, it was selected randomly a sample of 249 adolescents from Curitiba–Brazil. Adolescents were diagnosed according to the Portuguese version of the RDC/TMD criteria, Axis I by one calibrated examiner (kappa<0.80). Anxiety indicators were assessed according to the State-Trait Anxiety Inventory. Genomic DNA was extracted from saliva and five genetic polymorphisms in COMT and 5HTT were genotyped by real time PCR. Parametric and non-parametric tests were used to compare ‘TMD’ and ‘non-TMD’ groups. Multivariate analyses were used using sex as covariate
Results: 149 (59.8%) adolescents had at least one sign and/or symptom of TMD and 100 showed no signs. TMD was more prevalent in females (p=0.02, OR= 1.82, CI 1.08–3.04). The mean anxiety level was 43.7 (SD 0.7) in the TMD group and 35.7 (SD 0.8) in the non-affected group (p<0.0001). Multivariate analysis, adjusted by sex, demonstrated that polymorphisms in 5HTT and COMT were associated with myofacial pain, disc displacement and TMJ pain (p<0.05). Polymorphisms in 5HTT and COMT were not associated with anxiety level.
Conclusions: Polymorphisms in 5HTT and COMT are associated with TMD in adolescents.