Triggering receptor expressed on myeloid cells 2 (TREM2), a receptor on microglial membranes, has emerged as a research focus in Alzheimer’s disease (AD), supported by the positive results of genome-wide association studies (GWAS) over the past decade (Bertram and Tanzi, 2019). The gene discussed is TREM2; the disease is early-onset autosomal dominant Alzheimer disease.