Cerebral accumulation of amyloidogenic proteins is a hallmark of neurodegenerative diseases; Aβ and tau accumulate in Alzheimer’s disease (AD), tau accumulates in frontotemporal dementia (FTD), and α-synuclein accumulates in Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). This evidence concerns the gene MAPT and Lewy body dementia.