TREM2 and frontotemporal dementia: Mutations of TREM2 have been associated with an increased risk of various neurodegenerative disorders, including late onset AD (associated with heterozygous coding variants in TREM2, particularly, R47H), Nasu-Hakola disease and frontotemporal dementia (associated with homozygous missense TREM2 mutations T66M/T66M and W50C/W50C) [80, 81].