HTRA1 and CADASIL: Currently, more than 10 genes are known to cause monogenic CSVD (mgCSVD) in familial CSVD, including cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and high-temperature requirement A serine peptidase 1 (HTRA1)-related CSVD.5 6 Recently, mgCSVD caused by HTRA1 mutations has been increasingly reported.