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 - Northwestern Memorial Hospital - Chicago

Moyamoya Disease

Moyamoya disease is a rare, progressive cerebrovascular disorder caused by gradually blocked large arteries at the base of the brain in an area called circle of Willis. The name “moyamoya” means “puff of smoke” in Japanese and describes the look of the tangle of tiny vessels that form to compensate for the blockage.

Incidence of Moyamoya

Moyamoya disease was first described in Japan in the 1960s and it has since been found in individuals in the United States, Europe, Australia, and Africa.

The disease primarily affects children, but it can also occur in adults.

Causes of Moyamoya

Researchers think that Moyamoya disease is caused by inherited genetic abnormalities since it tends to run in families. Studies that look for the abnormal gene(s) may help reveal the pathophysiology that causes the disorder.


Adults most often experience a hemorrhagic stroke due to recurring hemorrhage from the affected brain vessels.

Individuals with this disorder may have the following symptoms:

  • Disturbed consciousness
  • Speech impairment (usually aphasia)
  • Sensory and cognitive impairments
  • Involuntary movements
  • Vision problems
Last UpdateAugust 28, 2012