Tau tangles are present in the brains of patients with progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), Pick disease, dementia pugilistica, frontotemporal dementia, and parkinsonism linked to chromosome‐17 (FTDP‐17 or frontotemporal lobar degeneration with tau pathology (FTLD‐tau)), and other neurodegenerative diseases, including Alzheimer's disease (AD), the most prevalent tauopathy and cause of dementia.1 This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.