Measurements of non‐phosphorylated tau, or “total tau” (T‐tau) in cerebrospinal fluid (CSF) is an established biomarker of neurodegeneration intensity in Alzheimer's disease (AD) [18], and increased concentrations of T‐tau in blood have also been reported in different acute neurological conditions including acute ischemic stroke [19, 20, 21, 22, 23, 24]. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.