In addition to TREM2, mutations in the myeloid receptor CD33 (also known as Siglec-3) [5–7], complement receptor 1 (CR1) [1], and myeloid cell-expressed membrane-spanning 4-domains subfamily A member 6A (MS4A6A) and MS4A4E [6, 7] have been shown to increase the risk of developing AD. Here, TREM2 is linked to Alzheimer disease.