MAPT and early-onset autosomal dominant Alzheimer disease: Microtubule Associated Protein Tau encodes the microtubule‐associated protein tau and promotes microtubule assembly and stability and might be involved in the establishment and maintenance of neuronal polarity. Mutations have been associated with several neurodegenerative disorders such as Alzheimer's disease, Pick's disease, frontotemporal dementia, cortico‐basal degeneration, and progressive supranuclear palsy.