CHGA and type 1 diabetes mellitus: T1D is thought to be initiated by a loss of T‐cell tolerance toward insulin, but then spreads to target other islet‐beta cell‐derived proteins such as glutamic acid decarboxylase 65, chromogranin A (ChgA), islet‐specific glucose‐6‐phosphatase catalytic subunit‐related protein (IGRP) and others including neoantigens.1