Microglia express multiple receptors that recognize different types of stimuli and mediate activation of Toll-Like Receptors (TLRs) and Triggering Receptor Expressed on Myeloid cells 2 (TREM2), with the latter attracting considerable interest since GWAS studies identified multiple TREM2 variants associated with an increased risk of developing AD [133–136]. The gene discussed is TREM2; the disease is Alzheimer disease.