MAPT and Alzheimer disease: Alzheimer's disease (AD), characterized by progressive cognitive decline and neuropathological hallmarks including β‐amyloid (Aβ) plaques and tau tangles,[1, 2, 3] lacks reliable early specific diagnostic markers.[4] Pathological changes in AD, known as “preclinical AD”, start to occur 10–20 years before clinical symptoms.[5] Therefore, developing a non‐invasive diagnostic technology to detect early molecular events is key for early discovery, diagnosis, and intervention to slow disease progression as well as improve the survival rates of patients with AD.