Over the past two decades, robust efforts to develop non-invasive diagnostic assays for AD have led to protocols that measure cerebrospinal fluid (CSF) levels of Tau, hyperphosphorylated Tau (pTau) [28–31] and AβPP-Aβ [32–38], and positron emission tomography (PET) to image aberrant brain accumulations of AβPP-Aβ [39]. Here, APP is linked to Alzheimer disease.