We particularly took note of any genes which were enriched in microglial expression because several genes known to affect AD (e.g., CR1, MS4A, HLA, and TREM2)2,31–34 are microglia genes involved in pathways related to amyloid beta (Aβ) clearance or autophagy, as is LRRC25. The gene discussed is TREM2; the disease is Alzheimer disease.