HTRA1 and CARASIL: CARASIL (cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy) (OMIM 600142) causes lacunar stroke and early onset vascular dementia, and derives from recessive mutations in the HtrA serine protease (HTRA1) gene, which is involved in TGF-beta signaling [16].