This module was expressed predominantly by the ARM subpopulation of activated microglia, which are synonymous with the disease-associated microglia (DAM) subpopulations seen in AD mouse models.27,43 Interestingly, the hub genes of this module (Spp1, Clec7a and Lilrb4a; Fig. 4A) have been reported to mark microglia scavenging fragmented myelin in the corpus callosum, which also become more numerous with ageing.8 This module is significantly enriched for biological annotations related to phagocytosis, cytokine production and TYROBP signalling (Supplementary Fig. 5A). The gene discussed is SPP1; the disease is Alzheimer disease.