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Published on: September 13, 2024
Genetic susceptibility to temporomandibular joint involvement in juvenile idiopathic arthritis
P Niibo1, T Nikopensius2, T Jagomägi1
1Institute of Dentistry, University of Tartu, Tartu, Estonia.
Insights
This study identified six genetic loci associated with temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) patients. These findings offer insights into genetic susceptibility factors for TMJ-JIA.
Area of Science:
- Genetics
- Rheumatology
- Immunology
Background:
- Juvenile idiopathic arthritis (JIA) is a common childhood rheumatic disease.
- Temporomandibular joint (TMJ) involvement is frequent in JIA, potentially leading to growth disturbances and functional deficits.
- TMJ damage in JIA can cause micrognathia and open bite, impacting aesthetics and function.
Purpose of the Study:
- To investigate the role of genetic factors in TMJ involvement in JIA.
- To identify genetic loci associated with TMJ-JIA using a Genome-Wide Association Study (GWAS) approach.
- To explore genetic susceptibility in TMJ-JIA, a condition previously unstudied in this context.
Main Methods:
- A case-control study design was employed with 55 JIA patients with TMJ involvement and 208 controls without TMJ involvement.
- Genotyping was performed using Illumina HumanOmniExpress BeadChip arrays.
- Data imputation utilized a nationwide reference panel from the Estonian Biobank (2240 individuals).
Main Results:
- Six genetic loci were significantly associated with the risk of TMJ-JIA in the Estonian cohort.
- Strongest associations were found at CD6 rs3019551, SLC26A8/MAPK14 rs9470191, NLRP3 rs2056795, and MAP2K4 rs7225328.
- These loci highlight potential genetic underpinnings of TMJ susceptibility in JIA.
Conclusions:
- This research provides initial insights into genetic risk loci for TMJ involvement in JIA.
- The identified loci are implicated in immunological pathways.
- These genomic regions may confer susceptibility to TMJ involvement in Estonian JIA patients.
Background:
Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic condition of childhood. Temporomandibular joint (TMJ) is among the most commonly affected joints in JIA patients. When JIA involves the TMJ, it may affect condylar growth in the joint; therefore, JIA patients are at risk of unfavourable long-term outcomes from associated joint damage. If undetected, TMJ involvement can lead to various functional disabilities such as reduced mandibular mobility and disorders of the mastication muscles. Limitations in sagittal and vertical mandibular growth can result in micrognathia and anterior open bite with aesthetic and functional restrictions.
Objective:
Genetic factors may play a role in determining which individuals are more prone to develop TMJ disorders or in predicting the severity of the disease process. Therefore, we applied a GWAS approach to identify loci associated with TMJ involvement in a sample of Estonian patients with JIA. Our aim was to address the potential role of genetic susceptibility factors in TMJ-JIA, a condition not previously studied in this context.
Methods:
The case group consisted of 55 JIA patients with TMJ involvement and 208 patients without TMJ involvement comprised the control group. The entire cohort was genotyped using the Illumina HumanOmniExpress BeadChip arrays. Imputation was performed using a nationwide reference panel obtained of 2240 individuals whose data were obtained from the Estonian Biobank.
Results:
We identified six loci as being associated with the risk of TMJ-JIA in Estonian JIA patients. The strongest associations were identified at CD6 rs3019551 (P = 3.80 × 10-6), SLC26A8/MAPK14 rs9470191 (P = 6.15 × 10-6), NLRP3 rs2056795 (P = 8.91 × 10-6) and MAP2K4 rs7225328 (P = 1.64 × 10-5).
Conclusion:
This study provides first insights into the risk-associated loci between JIA and its manifestation in the TMJ. The reported loci are involved in molecular pathways of immunological relevance and likely represent genomic regions that render the TMJ susceptible to involvement by JIA in Estonian patients.
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