Possible association of temporomandibular joint pain and dysfunction with a polymorphism the serotonin transporter gene

The purpose of this study was to evaluate the relationship between temporom andibular joint pain and dysfunction and serotonin transporter (5-HTT) gene polymorphism. Forty-eight patients with temporomandibular joint pain and 1 11 healthy control subjects were examined. The results for the patients and control subjects were not significantly different (P > .05). The analysis of genotype distribution (homozygous for STin 2.10 genotypes of the variabl e-number tandem-repeat polymorphism) showed significant differences between the patients and control subjects (P = .003). ST 2.10 allele was more freq uent in the patients with temporomandibular joint pain and dysfunction. In the control group, however, STin 2.12/12 genotype was significantly higher (P = .017). In the patients who were homozygous or heterozygous for variabl e-number tandem-repeat variants of 5-HTT STin 2.12 copies, the average scor es of somatization and anger were significantly higher than those who were homozygous for STin 2.10 variant (P < .05). The patients who were homozygou s for STin 2.10 genotype were also homozygous for "L" genotype (P = .019). However, this was not the condition in the control subjects. This study doe s not provide evidence to support the involvement of 5-HTT gene-linked poly morphic region in temporomandibular joint pain and dysfunction. Our finding s indicated that only the presence of the homozygous STin 2.10 genotype of variable-number tandem-repeat is likely to play a substantial role in the g enetic predisposition to temporomandibular joint pain and dysfunction and t hat the STin 2.12/12 genotype may have a protective role against temporoman dibular joint pain and dysfunction.