Recent studies have attempted to identify a microglial gene signature in healthy aging as well as in disease using the established microglial marker, TMEM119 and a cell-mapping tool, CellMapper. Thirty microglia-specific genes not previously identified were found to be enriched in several areas of the healthy human brain, including in areas that are susceptible to AD; these included TREM2, TLR7, CSF2RAC3, and C1QB (Bonham et al., 2019). The gene discussed is TREM2; the disease is Alzheimer disease.