Is catechol-O-methyltransferase gene associated with temporomandibular disorders? A systematic review and meta-analysis.

BACKGROUND: Temporomandibular disorder (TMD) is a condition, in which multiple factors act synergistically to determine the outcome of the disorder. AIM: A systematic review and meta-analysis was conducted to evaluate the association between genetic polymorphisms in catechol-O-methyltransferase (COMT) and TMD. DESIGN: Observational studies that investigated this association were included. The risk of bias and study quality were evaluated according to the Newcastle-Ottawa tool. The meta-analysis was performed for each polymorphism associated with TMD signs and symptoms. RESULTS: A total of 1903 articles were identified. Ten remained in the qualitative analysis: six were classified as low risk of bias and four with moderate risk of bias, and three were included in the meta-analysis. The polymorphism rs6269, in the genotypic model (0.65; CI = 0.44-0.97; P = .04) and in the allelic model (0.73; CI = 0.54-0.98; P = .04), was associated with myofascial pain. The rs9332377 was associated with myofascial pain in the genotypic model (2.69; CI = 1.51-4.76; P = .0007) and in the allelic model (1.46; CI = 1.01-2.13; P = .05) and with painful TMD in the genotypic model (2.08; CI = 1.27-3.40; P = .004) and in the allelic model (1.34 CI = 0.98-1.82; P = .06). CONCLUSION: The polymorphisms in COMT were significantly associated with TMD.