CSF1R and Leukoencephalopathy: The “DSS‐Pyle disease spectrum” features generalized osteosclerosis and irregular dysplastic metaphyses associated with neonatal and infant lethality from leukoencephalopathy, intracranial calcification, Dandy‐Walker malformation, cystic dilation of the posterior fossa and ventricles, and agenesis of the corpus callosum.(48, 49) In 2017, in first‐cousin carrier parents, heterozygous mutation (p.Y540*) of CSF1R was detected.(48) Biallelic CSF1R mutations were identified by Guo and colleagues(22) and Kındış and colleagues(35) in 2019 and 2021, respectively.