TREM2 and frontotemporal dementia: Triggering receptor expressed on myeloid cells 2 (TREM2) is expressed in microglia, and its genetic variants R47H and Y38C are linked to AD, frontotemporal dementia, and Nasu-Hakola disease, which is an early onset of dementia characterized by white matter pathology (Yaghmoor et al., 2014).