Genome wide association studies (GWAS) have identified several rare, heterozygous variants of TREM2 that increase risk of AD, including R47H TREM2, which increases AD risk about four‐fold (Giraldo et al., 2013; Guerreiro et al., 2012; Jonsson et al., 2013; Olufunmilayo & Holsinger, 2022). This evidence concerns the gene TREM2 and Alzheimer disease.