Association of Matrilin-3 Gene Polymorphism with Temporomandibular Joint Internal Derangement.

AIMS: Temporomandibular joint internal derangement (TMJ ID) is a multifactorial complex disease characterised by articular disc degeneration. Matrilin-3 is a cartilage and bone-specific adaptor protein, and amino-acid substitutions in the protein are associated with skeletal diseases and joint disorders. We aimed to detect the variants of Matrilin-3 gene (MATN3) in a TMJ ID case-control group and to investigate the risk association of the detected variants with TMJ ID.

MATERIALS AND METHODS: A case control study was conducted consisting of 57 unrelated TMJ ID patients (32.7 ± 8.2) and 96 unrelated healthy controls (26.63 ± 3.05) without TMJ ID to look for associations with variants of the MATN3 gene. DNA from individual subjects was extracted and each of the eight exons was amplified by polymerase chain reaction using and analyzed by single-strand conformational polymorphism (SSCP) analysis. SSCP variants were subjected to DNA sequence analysis, which yielded band pattern variations in exon 2 of the gene. We further analyzed exon 2 by DNA sequencing to determine the sequence of these variants.

RESULTS: We identified SSCP band patterns variants in exon 2 of the MATN3 gene which upon sequencing revealed a single C to T transition mutation (rs28598872) c.447 C>T (g.11608 C>T). This polymorphism is predicted to result in a synonymous mutation (pAla149 = ). The TT and CT genotypes were more prevalent than the CC genotype in TMJ ID patients compared to the control group with a risk factor of 2.12 (confidence intervals [CI] :0.88-5.08) and 2.0 (CI:0.726-5.508). In addition, TMJ ID patients were divided into two groups as anterior disc displacement with reduction (ADDWR) and anterior disc displacement without reduction (ADDWOR) and compared with the controls. The TT and CT genotypes were more prevalent than the CC genotype in ADDWR patients compared to the control group with a risk factor of 3.85 (CI:0.927-16.048) and 3.75 (1.02-13.786), respectively. We found that, among ADDWR patients, the T allele is a risk factor both in homozygous and heterozygous carriers (p < 0.052, p < 0.036).

CONCLUSION: The results of the study indicate a potential role for the MATN3 rs28598872 polymorphism in the pathogenesis of TMJ ID.