Of note, the pattern of differently altered BACE1 and Ng levels in A+/T−/N− and A+/T+/N+ groups resulted in a stage-wise elevation of Ng/BACE1 ratios through the Alzheimer’s disease continuum and was more strongly associated with baseline memory performance and later decline than Ng or BACE1 alone. Here, BACE1 is linked to Alzheimer disease.