Of the 44 SNPs (not including HLA and KIF5A regions, the latter being a deletion polymorphism and not analyzed in this study) most strongly associated with RA 9, 19 showed evidence for association with RF‐positive polyarticular JIA (P < 0.05) (see Supplementary Table 3, http://onlinelibrary.wiley.com/doi/10.1002/art.40443/abstract). Here, KIF5A is linked to juvenile idiopathic arthritis.