It is possible that the main title of the report Moyamoya Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
Moyamoya syndrome is a progressive disorder that affects the blood vessels in the brain (cerebrovascular). It is characterized by the narrowing (stenosis) and/or closing (occlusion) of the carotid artery inside the skull, the major artery that delivers blood to the brain. At the same time, tiny blood vessels at the base of the brain open up in an apparent attempt to supply blood to the brain distal to the blockage. These tiny vessels are the "moyamoya" vessels for which the disease was named. Inadequate blood supply then leads to reduced oxygen delivery to the brain, and it is this oxygen deprivation that causes the signs of moyamoya. One of the symptoms is typically stroke, which results in paralysis of the face, arms or legs, loss of speech, etc., or temporary loss of neurologic function of body parts or speech (transient ischemic attacks). Other symptoms that may result include headaches, visual disturbances, developmental delay, and seizures. Approximately 10% of cases of moyamoya in Asian countries have a genetic cause. Patients with this arteriopathy that occurs either on a familial or idiopathic basis are said to have moyamoya disease. Patients in whom the artery changes occur in association with another process such as sickle cell disease or Down syndrome are said to have moyamoya syndrome. In this report, we use the term "moyamoya syndrome" as a shorthand for both forms.
NIH/National Institute of Neurological Disorders and Stroke
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Genetic and Rare Diseases (GARD) Information Center
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