Genetic and neuropathological studies have implicated the neuronal microtubule-associated protein Tau (MAPT) as a central player in a wide range of adult-onset neurodegenerative disorders including Alzheimer’s disease (AD), frontotemporal dementia (FTD) and related tauopathies such as progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD)1. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.