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