MAPT and Alzheimer disease: While few neuropathological investigations of the pThr217 site have been conducted, the pThr217 site has been shown to differentiate AD from other neurodegenerative diseases [21,50] and investigation of pThr217/Thr217 has revealed high correlation with tau and amyloid positron emission tomography, more so than other measures using immunoassays as well as mass spectrometry [19], which led to our interest in this site.