For example, Lyz2 and Apoe, two genes that were previously associated with stage one of activation in Alzheimer’s Disease, were only enriched in one of the four activated microglia clusters (Cluster #2), yet another prominent Stage 1 marker, Cstb, was not similarly enriched in this cluster (Fig. 4e, middle row). This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.