NDDs all show accumulation of abnormally folded proteins, including β-amyloid (Aβ) and Tau in AD, α-synuclein (α-syn) in PD, TAR DNA-binding protein 43 (TDP-43) in ALS and huntingtin in Huntington’s disease (HD) [193–195]. The gene discussed is MAPT; the disease is Huntington disease.