Mutations in NOTCH3 have been identified as the underlying cause of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the most common inherited stroke and dementia syndrome in the group of degenerative small vessel diseases [23]. This evidence concerns the gene NOTCH3 and cerebral arteriopathy with subcortical infarcts and leukoencephalopathy.