Overall, there is compelling evidence supporting that a dysregulated ITIM/ITAM signaling axis, arising from polymorphisms in ITIM/ITAM-signaling SIGLECs or ITAM-signaling TREM2, results in an impaired microglial homeostatic function, potentially serving as an underlying mechanism that contributes to the onset and progression of AD and other types of dementias (129). The gene discussed is TREM2; the disease is Alzheimer disease.