SPI1 and Alzheimer disease: Pu.1 is a myeloid-lineage transcription factor essential for microglial identity and function {Cakir, 2022} {Smith, 2013} and has been genetically and functionally linked to AD, with higher PU.1 levels being associated with an increased AD risk, while lower levels are protective {Huang, 2017} {Pimenova, 2020} {Ralvenius, 2024}.