MAPT and early-onset autosomal dominant Alzheimer disease: Abnormal phosphorylation, however, triggers microtubule-bound tau to be released.1,2 Hyperphosphorylated tau (ptau) aggregates generate neurofibrillary tangles (NFTs) that are considered the pathological hallmark of tauopathies including Alzheimer disease (AD), chronic traumatic encephalopathy (CTE), and frontal-temporal dementia (FTD), among others.2–5