ABSTRACT
Moyamoya disease (MMD) is a steno-occlusive disease of the cerebral artery around the circle of Willis. It was first described in 1957 in Japan and named because the characteristic appearance of the basal collaterals in cerebral angiography looks like “a puff of smoke” (moyamoya in Japanese). MMD is one of the major causes of stroke in children worldwide, however most common in Korea, Japan and China. In 2011 the ring finger protein 213 gene (RNF213) was identified as a susceptibility gene for MMD. The RNF213 R4810K variant is an Asian founder mutation common to above nations with carrier rates of 0.5-2% of the general population but a 1/150 penetrance of clinical MMD. MMD patients in Korea and Japan harbors RNF213 R4810K variant in 70-90%. In MMD arterial stenosis was found to occur systematically, not only in the intracranial cerebral arteries but also in renal, coronary, pulmonary arteries, suggesting that MMD is a systemic vasculopathy. These extracranial vasculopathy (ECV) is rare but important as a cause of renovascular hypertension, ischemic heart disease, and pulmonary hypertension especially in children with MMD or family members of MMD. Clinical features of ECV will be reviewed in this article.