Dense genotyping of immune-related disease regions identifies 14 new susceptibility loci for juvenile idiopathic arthritis

Analysis of the ImmunoChip single nucleotide polymorphism (SNP) array in 2816 individuals, comprising the most common subtypes (oligoarticular and RF negative polyarticular) of juvenile idiopathic arthritis (JIA) and 13056 controls strengthens the evidence for association to three known JIA-risk loci (HLA, PTPN22 and PTPN2) and has identified fourteen risk loci reaching genome-wide significance (p < 5 × 10(-8)) for the first time. Eleven additional novel regions showed suggestive evidence for association with JIA (p < 1 × 10(-6)). Dense-mapping of loci along with bioinformatic analysis has refined the association to one gene for eight regions, highlighting crucial pathways, including the IL-2 pathway, in JIA disease pathogenesis. The entire ImmunoChip loci, HLA region and the top 27 loci (p < 1 × 10(-6)) explain an estimated 18%, 13% and 6% risk of JIA, respectively. Analysis of the ImmunoChip dataset, the largest cohort of JIA cases investigated to date, provides new insight in understanding the genetic basis for this childhood autoimmune disease