Previously, histological analysis was required for a definitive diagnosis; however, in 2011, Rademakers et al. reported a disease-specific genetic mutation affecting the tyrosine kinase domain of colony-stimulating factor 1 receptor (CSF1R).4 Researchers subsequently published many reports on clinical and genetic diagnoses of HDLS.3,5–7. This evidence concerns the gene CSF1R and Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia.