MAPT and Alzheimer disease: In fact, clinical diagnosis of AD is based on decline in cognition and positive biomarker assays of Aβ and/or tau in positron emission tomography (PET) scans and in cerebral spinal fluid (CSF) levels, or in post-mortem brain tissue (Jack et al., 2011; Blennow et al., 2015; Knopman et al., 2016; Selkoe and Hardy, 2016).