No evidence for genetic association of interferon regulatory factor 1 in juvenile idiopathic arthritis

Objective. Juvenile idiopathic arthritis (JIA) comprises several clinically distinct subgroups and is the most widespread cause of chronic childhood disability. A significant association between JIA and a polymorphism in the interferon regulatory factor 1 (IRF-1) gene has previously been reported, implicating IRF1 in disease susceptibility. The aim of this study was to replicate the IRF1 association in JIA using single-marker and haplotype analyses in a case-control study, using control subjects different from those in the previous study and a larger cohort of patients (n = 765). Methods. DNA from 765 patients with JIA and 508 unaffected control subjects was genotyped for 4 single-nucleotide polymorphisms in the IRF-1 gene. Association of genotypes at the IRF1 loci was assessed using single-marker and haplotype analyses. Results. No significant differences in genotype frequency or allele frequency were observed between patients and control subjects. Conclusion. This replication study used a much larger patient cohort to examine the association of IRF1 in JIA. However, despite the increased statistical power, we observed no significant association for IRF1 markers, either individually or as haplotypes. It is therefore unlikely that this gene is involved in JIA susceptibility. © 2007, American College of Rheumatology.