CADASIL is an autosomal dominant non-atherosclerotic vasculopathy that frequently presents as recurrent subcortical strokes, or vascular dementia in middle age. Some patients may have prominent mental symptoms or migraine. Widespread white matter demyelination and subcortical lacunar infarcts are demonstrated by magnetic resonance imaging. Demonstration of granular osmophilic material in arteries in skin biopsies is a useful diagnostic tool. CADASIL has been linked to mutation in the Notch 3 gene locus on chromosome 19. Genetic testing is available for clinical diagnosis.