TREM2 and Alzheimer disease: TREM2 mRNA in the dlPFC and PCC was higher in individuals with a clinical diagnosis of AD compared to those with no cognitive impairment (NCI) (Fig. 1A; p = 0.030, and p = 0.043, respectively) but no different across APOE-ε4 carrier status (Supplementary Figure 1A-B; p = 0.095 and p = 0.071, respectively).