CD33 and Alzheimer disease: Apart from the APOE variants, the AD-group included 15 variants, all of which were among the first to be associated with AD through GWAS (in/near CR1, CD33, BIN1, MS4A6A, PICALM, and SLC24A4), eventually representing variants with the strongest effect on AD (Harold et al., 2009; Lambert et al., 2009).