IAPP and Parkinson disease: PMDs develop and progress with a distinctive deposition of misfolded proteins such as tau and β-amyloid (Aβ) in AD [8], α-synuclein in PD [19] and dementia with Lewy bodies (DLB) [23], or amylin (also named islet amyloid polypeptide (IAPP)) in T2DM [12].