Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant disorder caused by mutations in the NOTCH3 gene in chromosome 19p13 (Tournier-Lasserve et al., 1993; Joutel et al., 1996) and is the most common hereditary small vessel disease, with clinical frequencies of 2-5/100,000 individuals (Joutel et al., 1997; Rutten et al., 2016). The gene discussed is NOTCH3; the disease is CADASIL.