MAPT and early-onset autosomal dominant Alzheimer disease: Misfolded tau protein deposits in neurons represent the neuropathological hallmark in many neurodegenerative disorders, including Alzheimer's disease (AD), frontotemporal dementia (FTD), progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), argyrophilic grain disease, and Down syndrome (Murray et al., 2014; Wang and Edison, 2019).