On the one hand, reduction in TREM2 ameliorated several aspects of AD pathology, including inflammation, astrocytosis, and amyloid plaque burden (Jay et al, 2015), while on the other hand, Trem2 deficiency leads to exacerbated disease pathology including increased amyloid plaque burden (Wang et al, 2015). This evidence concerns the gene TREM2 and Alzheimer disease.