IL2RA and rheumatoid arthritis: Diogo and colleagues [22] applied this strategy to the exons of 25 RA genes discovered by GWAS while utilizing four burden methods and identified a total of 281 variants (83% with minor allele frequency <1% and 65% previously undescribed), with an accumulation of rare nonsynonymous variants located within the IL2RA and IL2RB genes that segregated only in the RA cases.