SPI1 and Alzheimer disease: Since we and others have already been investigating the role of SPI1/PU.1 in microglia33,34,45–47, we decided to focus our functional validation efforts for this study on the other strong candidate DLAM TF BHLHE41 and its close homolog BHLHE40, which we (this study) and others13,19,48 have nominated as a candidate transcriptional regulator of DAM and similar neurodegeneration- and demyelination-related microglial transcriptional responses in mice, and which resides in the vicinity of a locus recently associated with AD risk in a GWAS of African-American individuals37.