MAPT and Alzheimer disease: The average fold increase in CSF tau levels in AD and CJD versus HC was highest for MR-tau (AD versus HC 4.1, CJD versus HC 36.6), followed by NT1-tau (AD versus HC 2.6, CJD versus HC 26.8), and lowest for FL-tau (AD versus HC 1.7, CJD versus HC 2.7).