The pathology of neurodegenerative disorders such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD) involves an accumulation in the central nervous system (CNS) of fibrillar aggregates formed by one or more peptides or proteins, including amyloid-beta and tau in AD, alpha-synuclein in PD, and TDP-43 and FUS in ALS/FTD. The gene discussed is MAPT; the disease is Parkinson disease.