HTT and Parkinsonism: In addition, the filaments derived from alpha‐synuclein, polyQ‐expanded huntingtin, and beta‐amyloid, which are associated with the neurodegenerative disorders such as Parkinson's, Huntington‘s, and Alzheimer's diseases, respectively, also trigger ER stress in neurons (Smith et al, 2005; Kim et al, 2008; Leitman et al, 2013).