Importantly, the most common TREM2 mutation is the arginine 47 histidine (R47H) variant, which appears to be associated with a reduced microglial uptake of Aβ and an increased risk of AD development (Guerreiro et al., 2013; Jonsson et al., 2013; Tanzi, 2015; Hansen et al., 2018). This evidence concerns the gene TREM2 and Alzheimer disease.