COL4A1 and Hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia: There are several hereditary forms of CSVD that have been identified, including CADASIL, cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), cathepsin A-related arteriopathy with strokes and leukoencephalopathy (CARASAL), hereditary diffuse leukoencephalopathy with spheroids (HDLS), COL4A1/2-related disorders, and Fabry disease.