Temporomandibular disorder is associated with a serotonin transporter gene polymorphism in the Japanese population

AIMS Recent genetic studies have linked serotonin-related genetic polymorphisms with diverse disorders characterized by functional somatic symptoms, including chronic fatigue syndrome, irritable bowel syndrome, and premenstrual dysphoric disorder. METHODS We investigated three serotonin-related genetic polymorphisms by screening genomic DNA of 36 temporomandibular disorder (TMD) patients. RESULTS A significant increase of longer alleles (l and xl) was found in the TMD patients compared to the controls both by the genotype-wise and the allele-wise analyses (both p < 0.01 by chi(2) test and Fisher's exact test). CONCLUSION Genetic factors that involve the serotonergic system may play a role in the pathogenesis of TMD.