TREM2 and Alzheimer disease: In the last years, genome-wide association studies (GWAS) have contributed a number of Alzheimer’s disease associated low penetrance genes, including ABCA7, ABI3, ACE, AC074212.3, ADAM10, ADAMTS1, ADAMTS4, ALPK2, ANKDR31, APH1B, ATP5H, BIN1, BZRAP1-AS1, CASS4, CD2AP, CD33, CELF1-MADD, CLNK, CLU, CNTNAP2, CR1, DSG2, ECHDC3, EPHA1, FERMT2, HESX1, HLA-DRB5–HLA-DRB1, HS3ST1, KAT8, IQCK, INPP5D, NME8, NYAP1, MS4A gene cluster, NDUFAF6, OARD1, PICALM, PLCG2, PTK2B, SCIMP, SLC24A4, SORL1, SPI1, TREM2, WWOX, ZCWPW1 [11–14].