The major AD risk factors, including ABI3, ABCA7, CD2AP, CD33, CASS4, EPHA1, NME8, SPI1, APOE, BIN1, CLU, CR1, FERMT2, INPP5D, IL1RAP, HLA-DRB1, HLA-DRB5, MS4A6A, MEF2C, PICALM, PLCG2, PTK2B, SORL1, TREM2, and ZCWPW1, have been identified through Genome-Wide Association Studies (GWAS). Here, CD33 is linked to Alzheimer disease.