AARS2 and Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia: The five main classifications of leukoencephalopathies are CSF1R-related leukoencephalopathy, AARS2-related leukoencephalopathy, AARS1-related leukoencephalopathy, HDLS-S-related leukoencephalopathy and CSF1R/AARS1/AARS2-negative ALSP.