CD33 and Alzheimer disease: Genome-wide association studies discovered, in addition to TREM2, the overexpressed genes in the DAM state selected for this study, TYROBP [39], APOE [40,41,42,43], CD33 [44,45,46,47] and MS4A [23,45], as AD-associated microglial risk genes [48], but there is less evidence for its involvement in ALS [17,49].