In recent years, genetic association studies, especially large-scale genome-wide association studies (GWASs), have identified some novel AD risk genes (PICALM, CLU, CR1, BIN1, CD2AP, CD33, ABCA7, EPHA1, PLCG2, ABI3, TREM2) and risk pathways associated with the potential pathogenesis and genetic mechanisms of AD (Liu et al., 2012, 2013a,b, 2014a,b,c, 2017b, 2018; Lambert et al., 2013; Bao et al., 2015; Chen et al., 2015; Li et al., 2015, 2016; Shen et al., 2015; Xiang et al., 2015; Zhang et al., 2015, 2016; Jiang et al., 2017; Jun et al., 2017; Sims and van der Lee, 2017). The gene discussed is TREM2; the disease is Alzheimer disease.