Lastly, large scale GWAS studies identifying single-nucleotide polymorphisms (SNPs) proximal to microglial-enriched, innate immune genes like CR1, CD33, MEF2C, HLA-DRB5-DRB1, PTK2b and TREM2 that significantly increase the risk of AD [5] have further underscored the critical role of microglia in neurodegeneration and disease progression. The gene discussed is TREM2; the disease is Alzheimer disease.