Moreover, the R47H TREM2 mutation increases the risk for Alzheimer's disease (AD) 3–4 fold (21, 22) and mutations in the TREM2 gene are thought to be linked with the impaired uptake of Aβ-lipoprotein complexes by microglia (23). This evidence concerns the gene TREM2 and early-onset autosomal dominant Alzheimer disease.