MAPT and Alzheimer disease: Therefore, measurements of plasma concentrations of brain metabolites, such as 40 and 42 amino acid-long Aβ peptides (Aβ40 and −42), tau protein variants, glial fibrillary acidic protein (GFAP), and neurofilament light (NfL), have emerged as diagnostic biomarkers of neurodegenerative diseases, currently in particular for Alzheimer’s disease (AD) and post-traumatic brain injuries3,4.