PTPRN and type 1 diabetes mellitus: Interestingly, while clinical T1D rarely occurs in APECED patients, high titers of antibodies against pancreatic autoantigens glutamic acid decarboxylase isoform 65 (GAD65) and tyrosine phosphatase-related islet antigen 2 (IA-2) were demonstrated in over 50% and 10% of U.S. patients, respectively [10].