HTT and Alzheimer disease: Tau, Aβ, the scrapie isoform of the prion protein (PrPSc), α-synuclein (α-Syn), huntingtin (HTT), neurofilament, SOD1, TAR DNA binding protein 43 (TDP-43), and ataxins 1-3 (ATXN1-3) aggregates affect the pathogenesis of AD, progressive supranuclear palsy (PSP), prion diseases, PD, HD, ALS, frontotemporal dementia (FTD), and spinocerebellar ataxia (SCA) that are neurodegenerative diseases [30,31].