BACE1 and Alzheimer disease: In the plasma of biologically determined AD compared to non‐AD (cohort 1), we observed six differentially deregulated proteins (Figure 1A), of which four upregulated proteins in AD passed multiple testing correction (p‐tau217, logFC = 1.68, Padj < 0.001; GFAP, logFC = 0.90, Padj = 0.003; p‐tau231, logFC = 0.90, Padj = 0.003; BACE1, logFC = 0.33, Padj = 0.02; Figure S1 in supporting information).