These include aggregates of α-synuclein in Parkinson’s disease (PD), amyloid-β plaques (Aβ) and inclusions of hyperphosphorylated tau in Alzheimer’s disease (AD), polyglutamine protein aggregates in Huntington’s disease (HD), and inclusions of TAR DNA-binding protein (TDP)-43 in amyotrophic lateral sclerosis (ALS). The gene discussed is MAPT; the disease is Alzheimer disease.