The association of genetic polymorphisms in serotonin transporter and catechol-O-methyltransferase on temporomandibular disorders and anxiety in adolescents

Background: Temporomandibular disorder (TMD) is a multifactorial condition involving environmental, psychological and genetic factors.

Objective: The aim of this case-control study was to evaluate the influence of genetic polymorphisms in 5HTT and COMT on TMD and anxiety in adolescents.

Methods: TMD was diagnosed and classified according to the RDC/TMD criteria. For case group, the following TMD categories were used: myofascial pain, disc displacement, arthralgia and painful TMD (myofascial and arthralgia). Anxiety levels were assessed according to the State-Trait Anxiety Inventory. Genomic DNA was extracted, and genetic polymorphisms were genotyped by TaqMan chemistry and endpoint analysis. Logistic multivariate regression was used to analyse the associations between TMD types and genotypes, anxiety level and genotypes, using an adjusted odds ratio (OR_a ; CI 95%) that considered the gender.

Results: In 5HTT, the rs1042173 was associated with painful TMD (arthralgia and myofascial pain) (OR_c = 1.97; CI 95%: 1.02-3.77; P = 0.04). Polymorphisms in COMT rs4818 were significantly associated with myofascial pain (OR_c = 2.15; CI 95%: 1.08-4.29; P = 0.02) and were borderline for painful TMD (OR_c = 1.85; CI 95%: 0.97-3.51; P = 0.06) and disc displacement (OR_c = 2.42; CI 95%: 1.00-5.87; P = 0.05). The rs6269 was borderline for myofascial pain (OR_c = 1.82; CI 95%: 0.92-3.59; P = 0.08) and disc displacement (OR_c = 2.38; CI 95% 0.95-5.97; P = 0.06) and also was associated with anxiety (OR_a = 2.34; CI 95% 1.04-5.25; P = 0.03).

Conclusion: Polymorphisms in 5HTT and COMT are associated with TMD in adolescents. Moreover, polymorphism in COMT is associated with anxiety in adolescents.