MAPT and early-onset autosomal dominant Alzheimer disease: Although this assumption is reasonable in the short run (Blennow et al., 2007; Slats et al., 2012; Le Bastard et al., 2013), the blood and CSF levels of tau rise with aging (Blomberg et al., 2001; Chiu et al., 2017), and with Alzheimer's disease progression (Palmqvist et al., 2019).