MAPT and Alzheimer disease: Interestingly, proNGF/Aβ1–42 levels were 50% higher in CDR 0.5 and CDR 1 compared to CDR 0, whereas proNGF/total tau and proNGF/phospho-tau were unchanged between groups, suggesting the inclusion of proNGF as a candidate biomarker will improve the diagnostic probability needed to identify people in the preclinical or prodromal stages of AD.