TREM2 and other late-onset AD susceptibility genes MS4A4A/4 E/6A, CD33, HLA-DRB5/DRB1, and INPP5D are all part of a distinctive brain coexpression module, which also contains the signaling partner for TREM2, TYROBP, or DAP12 (Forabosco et al., 2013, Hawrylycz et al., 2012, Zhang et al., 2013). This evidence concerns the gene TREM2 and Alzheimer disease.