As an example of how alterations in CSF dynamics can impact biomarker readings, low concentrations of all core biomarkers (ie, p-tau, t-tau, Aβ42, and Aβ40) are commonly seen in cases of idiopathic normal pressure hydrocephalus, not necessarily associated with AD pathophysiology.39 Interestingly, in the UGOT and ADNI cohorts, concentrations of Aβ40 and Aβ42 were clearly higher in the A−T+ group, compared with the A−T− group. Here, MAPT is linked to Alzheimer disease.