Meta-analysis from multiple genome-wide association studies (GWAS) in AD have recently identified an rs75932628 (R47H; loss of function) variant in TREM2 as a strong AD risk factor, conveying an increase in AD with an odds ratio of 1.3–8.8-fold (p = 0.0076) in recent studies, an effect size comparable to that of the APOEe4 allele (Gonzalez Murcia et al., 2013). Here, TREM2 is linked to Alzheimer disease.