It is known that several genes, expressed exclusively by microglia in the brain, such as CD33, a sialic-acid-binding immunoglobulin-like lectin (SIGLECs), and triggering receptor expressed on myeloid cells 2 (Trem2) carry single nucleotide polymorphisms (SNPs) that influence the risk for developing AD (7). This evidence concerns the gene TREM2 and Alzheimer disease.