Moyamoya disease is a disorder caused by blocked arteries at the base of the brain. The name “moyamoya” means “puff of smoke” in Japanese and describes the appearance of the tangle of tiny vessels that form to compensate for the blockage. As the normal blood vessels narrow and become blocked, a person may suffer a stroke – a life-threatening situation. No medication can stop or reverse the progression of moyamoya disease. Treatment focuses on reducing the risk of stroke and restoring blood flow to the brain.