TREM2 and Alzheimer disease: The interest in microglia-powered neuroinflammation has increased in recent years, mainly because of genome-wide association studies (GWAS) done on large cohorts, counting thousands of patients, identifying new loci associated with the risk of developing a sporadic form of AD (ATXN1, CD33, CLU, CR1, PICALM, BIN1, CD2AP, MS4A6A/MS4A4E, EPHA1, ABCA7, SHIP1, TREM2, and an unidentified locus on chromosome 14 (GWA_14q31.2)) [58,59,60,61,62,63].