AD is characterized by the aggregation of β-amyloid and the microtubule associated protein Tau; PD by the accumulation of the nerve terminal protein α-synuclein; ALS by deposition of phosphorylated TDP43 (a transcriptional repressor) and an enzyme that removes superoxide radicals, superoxide dismutase 1 (SOD1); and HD by the accumulation of the mutant protein huntingtin [2, 3]. Here, MAPT is linked to Alzheimer disease.