Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is an inherited disorder caused by a mutation in the NOTCH 3 gene, characterized by early onset of subcortical lacunar infarcts in the absence of vascular risk factors and cerebral microbleeds. The gene discussed is NOTCH3; the disease is CADASIL.