Today, the basic established Alzheimer’s disease (AD) biomarkers, Aβ-binding ligands used in positron emission tomography (PET), Aβ42, total-tau (ttau), and phosphor-tau (ptau) in cerebrospinal fluid (CSF) [3], reflect several key pathophysiological characteristics of the condition, and convey diagnostically appropriate data, including concerning its preclinical phase. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.