SNPs in the FOXP3 gene region show no association with Juvenile Idiopathic Arthritis in a UK Caucasian population

Objective. A region on the short arm of the X-chromosome, Xp11, has previously been linked to childhood-onset polyarthritis. Mapping to the linked region is FOXP3, a transcription factor that regulates regulatory T cell (Treg) development and function. The objective of this study was to determine whether single nucleotide polymorphisms (SNPs) in the FOXP3 gene region contribute to JIA susceptibility. Method. Nine FOXP3 SNPs were genotyped in 761 JIA cases and 402 controls using the Sequenom® MassARRAY® system. Association was measured using either χ2 or Fisher's exact test at the allelic and genotypic level. Furthermore, cases and controls were stratified by gender and association measured for each stratum. Results. None of the SNPs showed an association with JIA. Similarly, the lack of association was also evident in both the female and male cohorts. Conclusion. Although FOXP3 presents itself as a good candidate for contributing to JIA susceptibility, this study, which was powered to detect associations with genotypic relative risk >2 in the female cohort, has failed to find an association between SNPs in the FOXP3 gene region and JIA. © The Author 2007.