TREM2 and Alzheimer disease: Recent genome-wideassociation studies (GWAS) have identified rare variants in TREM2(Triggering Receptor Expressed on Myeloid cells 2) as significantgenetic risk factors for late-onset AD, with the R47H mutation inthe extracellular domain conferring a particularly strong effect., TREM2 functions as an immunomodulatory receptor on microglial surfacesand initiates intracellular signaling via its transmembrane adaptorDAP12 (DNAX-activating protein of 12 kDa).,