[An autopsy case of Down's syndrome with moyamoya syndrome].

We reported an autopsy case of Down's syndrome with moyamoya syndrome. A 30-year-old male with Down's syndrome suffered from a cerebral infarction and died of brain herniation. Cerebral angiography showed vascular abnormalities that were the same as moyamoya disease. Pathological findings revealed multiple stenosis of main trunk of the cerebral arteries. Pathologically, the stenosed vessels showed eccentric intimal thickness with cholesterin deposit, unlike moyamoya disease. There are only two previous reports of autopsied cases of Down's syndrome with moyamoya syndrome. We postulate that a protein encoded on chromosome 21 may be related to the pathogenesis of Down's syndrome with moyamoya syndrome.