MAPT and frontotemporal dementia: Intracellular accumulation of hyperphosphorylated tau has been widely observed in neurodegenerative diseases, such as AD, progressive supranuclear palsy (PSP), corticobasal degeneration, Pick disease, Huntington disease, and frontotemporal dementia with parkinsonism‐17 (Wang & Mandelkow, 2016).