Accumulation of misfolded phosphorylated tau and amyloid beta (Arnold et al., 2018) in the brain as well as the islet amyloid polypeptide (amylin) (Raimundo et al., 2020) co-secreted with insulin in the islet beta cells are major pathological features observed in T2D patients who develop AD. This evidence concerns the gene IAPP and Alzheimer disease.