IAPP and α‐synuclein, as well as Aβ and tau, have been found to be colocalized in pancreatic β cells in patients with synucleinopathies, which may underlie the appearance of insulin resistance in non‐T2DM AD, PD, or dementia with Lewy bodies patients.35, 36. This evidence concerns the gene MAPT and type 2 diabetes mellitus.