MAPT and early-onset autosomal dominant Alzheimer disease: The human tau protein is implicated in a wide range of neurodegenerative “tauopathy” diseases, consisting of Alzheimer’s disease (AD) and frontotemporal lobar degeneration which includes progressive supranuclear palsy, corticobasal degeneration, Pick’s disease, and FTLD-tau (frontotemporal dementia with parkinsonism caused by MAPT mutations).