PSEN1 and Alzheimer disease: The canonical Wnt signaling modulatory gene Dkk2 (Mao and Niehrs, 2003) was upregulated downstream of Trem2 in DAM/ARM cells in APP/PS1, PS2APP, 5xFAD, and APPNL-G-F AD mouse models in separate studies, making it a putative DAM/ARM marker gene (Friedman et al., 2018; Sala Frigerio et al., 2019; Meilandt et al., 2020).