What is Moyamoya Disease?
Moyamoya disease is an idiopathic rare steno-occlusive disease of the arteries of the circle of Willis, typically anterior circulation, with abnormal collateral development in lenticulostriate arteries, resulting in the characteristic angiographic puff of smoke appearance. Moyamoya disease may be more common in individuals of Asian descent, but non-Asian people can be affected. It has a bimodal distribution, with a peak in childhood (more ischemic) and adulthood (ischemic and hemorrhagic), and can be asymptomatic. Although a causal relationship is not well established, similar vascular changes may also be seen in association with prior radiation exposure, Down syndrome, sickle cell disease, neurofibromatosis, and atherosclerosis. This situation is often referred to as moyamoya syndrome.