CSF1R and neurodevelopmental disorder: However, in certain neurodevelopmental disorders, such as colony-stimulating factor 1 receptor (CSF1R)-related pediatric leukoencephalopathy—a condition caused by homozygous or heterozygous mutations in the Csf1r gene—microglia are permanently absent, leading to pronounced brain structural abnormalities, including white matter defects and cerebellar hypoplasia (Oosterhof et al., 2019).