There are several other rare hereditary forms of CSVD as follows: colony-stimulating factor 1 receptor [CSF1R, MIM*164770] mutations cause HDLS (62); CTSA mutations are the cause of CARASAL through the degradation of endothelin-1 and downregulation of oligodendrocyte (13); and Fabry disease is caused by the genetic mutations in the alpha-galactosidase-A gene (GLA-gene), located on the long arm of the X-chromosome (Xq22.1) (63). Here, CTSA is linked to Fabry disease.