CSF1R gene, one of the main causes of ALSP, encodes CSF1R protein which is a type III receptor tyrosine kinase belonging to the platelet-derived growth factor (PDGF) receptor family, which also includes PDGF-a and -b, the FMS-like tyrosine kinase 3 (FLT3) and the receptor for stem cell factor (c-KIT) [2]. The gene discussed is FLT3; the disease is Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia.