[Moyamoya associated with Down syndrome].

We present a case of a six-year-old girl with Down Syndrom who developed recurrent ischemic strokes. Cerebral angiography demonstrated a supraclinoid stenosis of the right internal artery, an occlusion of the left supraclinoid internal cerebral artery and dilated collateral vessels, consistent with Moyamoya disease. We emphasize the increased frequency of Moyamoya in patients with Down Syndrome and also the most important pathophysiologic, clinical and radiological findings of this disease.