Positive association of SLC26A2 gene polymorphisms with susceptibility to systemic-onset juvenile idiopathic arthritis.

OBJECTIVE: To investigate SLC26A2, the gene that causes diastrophic dysplasia, in juvenile idiopathic arthritis (JIA). METHODS: Nine polymorphisms across the SLC26A2 gene locus were investigated using MassArray genotyping in 826 UK Caucasian JIA cases and 617 ethnically matched healthy controls. RESULTS: Significant associations between multiple single-nucleotide polymorphisms (SNPs) across SLC26A2 and systemic-onset JIA were found. In each case, homozygosity for the minor allele conferred the increased risk of disease susceptibility: rs1541915 (odds ratio [OR] 2.3, 95% confidence interval [95% CI] 1.4-3.7, P=0.0003), rs245056 (OR 2.8, 95% CI 1.7-4.6, P=0.00002), rs245055 (OR 2.5, 95% CI 1.2-5.0, P=0.004), rs245051 (OR 2.3, 95% CI 1.4-3.7, P=0.0005), rs245076 (OR 2.7, 95% CI 1.3-5.4, P=0.0015), and rs8073 (OR 2.3, 95% CI 0.9-5.6, P=0.04). CONCLUSION: These findings show the value of using monogenic disease loci as candidates for investigation in JIA. We identified a subgroup-specific association between SNPs within the SLC26A2 gene and systemic-onset JIA. Our findings also highlight systemic-onset JIA as being a distinctly different disease from that in the other JIA subgroups.