As of 20 May 2021, based upon the available peer-reviewed literature, the total estimated global prevalence of mendelian adult-onset leukodystrophies is 300 cases/million and 10-25% of those cases are projected to be CSF1R-related ALSP patients. This evidence concerns the gene CSF1R and Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia.