TREM2 and Alzheimer disease: Genome-wide association studies (GWAS) and next-generation sequencing (NGS) have uncovered interesting Trem2 [p.R47H (rs75932628) and p.R62H (rs143332484)] and Plcg2 [p.P522R (rs72824905)] variants associated with sporadic AD risk factors (Sims et al., 2017; van der Lee et al., 2019).