Genetic polymorphisms in headache attributed to temporomandibular disorder: A case-control study.

OBJECTIVE

The aim of this study was to examine the relationship between three single nucleotide polymorphisms (SNPs): -308 G/A TNF-α, -174 G/C IL-6, and C677T MTHFR and the presence of headache attributed to temporomandibular disorder (HATMD).

DESIGN

This case-control study included a total of 68 patients with HATMD and 200 controls, aged 18 years and older. Both sets of participants included both genders. The diagnosis followed the diagnostic criteria for temporomandibular disorders (DC/TMD). The temporomandibular disorder pain screen was also applied. The -308 G/A TNF-α and 677 C/T MTHFR SNPs were genotyped using polymerase chain reaction-restriction fragment polymorphism (PCR-RFLP), and -174 G/C IL-6 SNP was performed by PCR. Allele frequencies and logistic regression analysis were used to assess the association between HATMD and genotypes.

RESULTS

The results revealed that the AA genotype of -308 G/A TNF-α SNP (ORGG/AA= 0.20, 95 % CI: 0.0568-0.7724,p = 0.0290) and the CT genotype of C677T MTHFR SNP (ORCC/CT = 0.40, 95 % CI: 0.2224-0.7350, p = 0.0042) were protective factors for HATMD risk. No significant association was found between -174G/C IL-6 SNP and the risk of HATMD (ORGG/CC = 0.58, 95 % CI: 0.2122-1.6367, p = 0.45).

CONCLUSION

The -308 G/A TNF-α and C677T MTHFR SNPs were identified as protective factors against the development of HATMD.