ERα polymorphism may increase the susceptibility of Temporomandibular Disorder

Temporomandibular Muscle and Joint Disorders (TMJD) are the most common cause of chronic pain in the orofacial region. The literature supports that TMJD affects women with more intensity and more frequency than men.

Objective: The aim of this study was to investigate whether an Estrogen Receptor α (Erα) gene polymorphisms (XbaI and PvuII) could contribute to the higher prevalence of TMJD in women. Methods: DNA was obtained from 200 women with TMJD (100 with chronic pain and 100 with signs of TMJD but no pain) diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) and 100 women without signs and symptoms of TMJD (control group). Restriction Fragment Length Polymorphisms of Polymerase Chain Reaction products were used to analyze XbaI and PvuII single nucleotide polymorphisms (SNPs) in DNA fragments which recently have been associated with higher prevalence of pain in females carrying Temporomandibular osteoarthritis.

A model directly characterizing specific DNA sequence variants based on the risk haplotypic structure implemented with the EM algorithm was used to analyze the data.

Results: The [CG] haplotype of the XbaI locus was significantly more prevalent in both TMJD groups when compared with the control group (p=0.0012). Specifically, the [CG] haplotype was more prevalent within the painful TMJD group versus control group (odds ratio=2.51, 95% CI=1.267,4.97) and in the TMJD no pain versus the control group (odds ratio=3.203, 95% CI=1.633, 6.284). The two TMJD groups did not differ from each other. Also, no differences separated to the control group and TMJD groups in PvuII frequencies. Conclusion: The presence of [CG] haplotype in the XbaI locus may increase the susceptibility of women develop TMJD.