Three haplotypes that are tagged by three single nucleotide polymorphisms (SNPs) have been defined in the IL2RA locus: the rs12722495 (previously rs41295061) protective haplotype that is only associated with T1D (OR = 0.62, p = 6.43×10−25), the rs2104286 protective haplotype that is associated with MS (OR = 0.85, p = 6.27×10−7), T1D (OR = 0.80, p = 1.27×10−13) and RA (OR = 0.76, p = 4.9×10−5), and the rs11594656 haplotype that is associated with protection from T1D (OR = 0.87, p = 3.37×10−6) but risk for MS (OR = 1.17, p = 7.67×10−4)[16], [24], [25]. This evidence concerns the gene IL2RA and rheumatoid arthritis.