Abstract Body

Moyamoya disease (MMD) is an uncommon vascular disease of unknown etiology to cause bilateral progressive stenosis and occlusion of arteries of the circle of Willis, and preferentially affects children and young adults, which is seen across the world, but is more common in East Asia. The word “moyamoya” means “puff of smoke” in Japanese, a term describing the appearance of net-like tiny collateral blood vessels. MMD may cause TIA, stroke, aneurysm, or bleeding in the brain. Ischemic stroke is dominant in children and hemorrhagic stroke is dominant in adults. Moyamoya-like vasculopathy develops in association with various systemic diseases and conditions, which is termed moyamoya syndrome or quasi-MMD. Unilateral MMD without any underlying disease is diagnosed with probable MMD. Ring finger protein (RNF213) was identified as a susceptibility gene for Asian populations. Experimental studies have suggested that RNF213 is related to angiogenesis and vascular inflammation. Recent studies reported that RNF213 variant increases the risk of atherothrombotic stroke and intracranial arterial stenosis. There is no medical treatment or endovascular intervention proven to halt the progression of MMD or prevention of stroke. In the Japan Adult Moyamoya (JAM) trial, which compared bilateral extracranial-intracranial direct bypass and conservative care in 80 patients with MMD with an age range of 18–65 years, patients in the bypass surgery group at the primary endpoint experienced significantly less recurrent intracranial hemorrhage, completed stroke, or crescendo TIA.