TREM2 and leukodystrophy: Triggering receptor expressed on myeloid cells 2 (TREM2) is also a key microglial transmembrane receptor that plays an essential role in normal microglial function, supported by the observation that loss‐of‐function variants in the human TREM2 gene result in Nasu‐Hakola disease, a rare leukodystrophy caused by lipid accumulation, demyelination, axonal loss, and gliosis and characterized by clinical symptoms that include bone cysts as well as cognitive decline, behavioral changes, motor symptoms, and seizures [8, 17, 18].