Genome-wide association study of degenerative bony changes of the temporomandibular joint.

OBJECTIVES: To identify susceptibility genes underlying degenerative bony changes of the temporomandibular joint (TMJ). MATERIALS AND METHODS: Bony changes of the TMJ condylar head were diagnosed by examination of panoramic radiographs and/or magnetic resonance images and/or computed tomography images. We conducted a genome-wide association study (GWAS) of 146 cases with TMJ degeneration and 374 controls from East Asian populations using an Illumina HumanOmniExpress BeadChip. After rigorous quality-control filtering, approximately 550,000 single nucleotide polymorphisms (SNPs) were used for tests of associations with disease status. RESULTS: Forty-one SNPs at 22 independent loci showed association signals at P < 1 x 10(-4). The SNP rs878962, which maps on an intron of TSPAN9 on chromosome 12, showed the strongest association (combined OR = 1.89, 95% confidence interval = 1.43-2.50, P = 8.1 x 10(-6)). According to in silico predictions of the 41 SNPs, two intronic SNPs of APOL3 (rs80575) and MRC2 (rs2460300) may fall within regulatory elements and affect DNA-protein interactions. We could not replicate SNPs located on genes that have been reported to be associated with temporomandibular disorder or temporomandibular osteoarthritis in previous studies at P < 1 x 10(-4). CONCLUSIONS: Our GWAS identified 22 independent loci showing suggestive association signals with degenerative bony changes of the TMJ. These loci provide good candidates for future follow-up studies.