Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is caused by mutations in CSF1R. Pathogenic mutations in exons 12–22 including coding sequence of the tyrosine kinase domain (TKD) of CSF1R were previously identified. The gene discussed is CSF1R; the disease is Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia.