In terms of pathology, neurodegenerative diseases are characterized by the central nervous system (CNS) aggregation of proteins, such as the aggregation of amyloid beta (Aβ) and hyperphosphorylated tau in AD, α-synuclein in PD and in LBD, TAR DNA-binding protein (TDP)-43 in ALS and fronto-temporal dementia (FTD) and Cytosine – Adenine - Guanine (CAG)-polyglutamine protein in HD [3]. The gene discussed is MAPT; the disease is Alzheimer disease.