TREM2 and Alzheimer disease: For instance, two recent studies performing single‐cell RNAseq of microglia (isolated as discussed below) in mouse aging and models of AD, multiple sclerosis, and ALS, defined a distinctive microglial molecular signature of disease defined as (DAM; Keren‐Shaul et al, 2017) or “microglia neurodegenerative phenotype” (MgND; Krasemann et al, 2017), suggested to be driven by TREM2.