HTRA1 and CADASIL: Additionally, hereditary small vessel diseases with cognitive deficits, namely cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), show loss of function of the HTRA1 or high-temperature requirement A serine peptidase 1 gene, which results in upregulation of TGFβ signaling [11,12].