First, a rare missense SNP, rs72824905 (P522R), reduces AD risk (Dalmasso et al., 2019; Kleineidam et al., 2020; Magno et al., 2019; Olive et al., 2020; Sims et al., 2017; Strickland et al., 2020; van der Lee et al., 2019) and appears a mild hypermorph in PLCG2 function (Magno et al., 2019; Solomon et al., 2022; Takalo et al., 2020). This evidence concerns the gene PLCG2 and Alzheimer disease.