MAPT and early-onset autosomal dominant Alzheimer disease: To explore how the abundances of phosphorylated tau epitopes change over the course of AD, the study participants of both cohorts were organized by clinical assessment and PET data to form an Alzheimer’s disease continuum (Fig. 1 A-G and Fig. 2 A-G), starting with young, healthy individuals, followed by cognitively unimpaired elderly without Aβ pathology (CU-), proceeding to cognitively unimpaired with Aβ pathology (CU +), symptomatic elderly with mild cognitive impairment and Aβ pathology (MCI +), and ending with clinical AD, verified by Aβ-PET or CSF Aβ1-42/1–40 ratio.