TREM2 and frontotemporal dementia: This is in line with what recently reported by Götzl et al. [86], showing that loss of TREM-2 enhances the expression of genes associated with a homeostatic microglial state in vivo, contrarily to the neurodegenerative microglial phenotype, which derives from the ablation of progranulin (GRN), an additional gene involved in neuroinflammation occurring in AD and FTD.