Microglia replacement halts the progression of microgliopathy in mice and humans

) is primarily expressed in microglia. Its monoallelic mutation causes CSF1R-associated microgliopathy (CAMP), a major form of adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) and a fatal neurological disease without clinical cure. We developed mouse models harboring human hotspot mutations of CAMP and replaced CSF1R-deficient microglia with CSF1R-normal cells through microglia replacement by bone marrow transplantation (Mr BMT), which attenuated pathology in mice. We further demonstrated that, in the context of CSF1R deficiency, traditional bone marrow transplantation (tBMT) in ALSP functions similarly to Mr BMT, efficiently replacing microglia and reducing disease progression.…