Proteins contained within the ‘core markers’ cluster included many neuronal 14–3-3 proteins (YWHAZ, YWHAB, YWHAG), previously shown to be increased in AD, as well as PPIA, a potential astrocytic marker, and GDI1, a marker of microglial activation, underlining the cell-type diversity of this cluster (Fig. 3 D). This evidence concerns the gene GDI1 and Alzheimer disease.