CTLA4 and type 1 diabetes mellitus: The genes included were selected from IL-2 interacting genes determined by STRING network analysis (IL2, IL2RA, IL10, IL27, IL7R, and DGKA region SNPs); CTLA4 was included due to its overlap with Idd5 and role in Treg function and PTPN2 due to the described effects of T1D-associated PTPN2 SNPs on IL-2 signaling [27].