Intraneuronal inclusions made of filamentous aggregates of the microtubule-associated protein Tau are hallmarks of Alzheimer disease (AD) and related neurodegenerative diseases termed tauopathies, which include progressive supranuclear palsy, corticobasal degeneration and frontotemporal lobe dementia. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.