GAD2 and type 1 diabetes mellitus: Next, we tested the level of GLUT2+ PB-IPC in a prediabetic patient, which displayed high incidence to develop T1D with 3-positive T1D-associated autoantibodies such as glutamic acid decarboxylase 65 (GAD-65), zinc transporter 8 (ZnT8), and islet cell antibody (ICA) [32,33].