These include β-amyloid (Aβ) peptides in the neuritic plaques of Alzheimer’s disease (AD), the fibrillation of tau protein to form neurofibrillary tangles in AD and Pick bodies in frontotemporal dementia (FTD), and alpha-synuclein in the Lewy bodies of Parkinson disease (PD) and in Lewy body disease [1,2]. The gene discussed is MAPT; the disease is Alzheimer disease.