PTPN2 and type 1 diabetes mellitus: The diminished IL-2 response in T1D may result from genetic variation, including multiple T1D-associated variants identified in at least 4 genes encoding unique proteins involved in the IL-2 pathway, including IL-2, IL-2Ralpha, IL-2Rbeta, and PTPN2 (protein tyrosine phosphatase N2) genes [50,53,54,55].