Although initially thought to be limited to the Asian population, moyamoya is now known to affect people from all races and ethnicities. The pie chart below shows data of patients treated at the Stanford Moyamoya Center.

One of the rarest forms of occlusive cerebrovascular disorders encountered in neurosurgery is moyamoya disease. Fragile blood vessels proliferate around a blocked artery in an attempt to bypass an occlusion. Their appearance on a cerebral angiogram resembles a "puff of smoke" or "moyamoya," a term coined by a Japanese team who first described the disease. It can affect both children and adults usually with symptoms of TIAs, strokes, headaches and seizures. There is no effective drug treatment for moyamoya disease and surgery is aimed at bypassing the blockage with another artery to restore normal blood flow. Dr. Steinberg has performed over 2,000 of these revascularization procedures for moyamoya, making his case experience with this disease one of the largest in the world.