Moyamoya disease

Moyamoya disease is a rare, progressive cerebrovascular disorder characterized by the narrowing and eventual occlusion of the internal carotid arteries and their major branches at the base of the brain. The name 'moyamoya' is Japanese for 'puff of smoke,' describing the appearance of the abnormal, fragile network of tiny collateral blood vessels that develop to compensate for the blocked arteries, as seen on cerebral angiography. The disease primarily affects the brain's blood supply and can lead to ischemic strokes, transient ischemic attacks (TIAs), hemorrhagic strokes, seizures, headaches, and cognitive decline. In children, the disease most commonly presents with ischemic symptoms such as stroke, weakness, or speech difficulties, while adults more frequently experience hemorrhagic strokes due to rupture of the fragile collateral vessels. Some patients also develop involuntary movements or progressive cognitive impairment. Moyamoya disease can occur as an isolated condition (moyamoya disease) or in association with other conditions such as Down syndrome, neurofibromatosis type 1, or sickle cell disease, in which case it is referred to as moyamoya syndrome. The condition is most prevalent in East Asian populations, particularly in Japan, Korea, and China, though it is recognized worldwide. Both unilateral and bilateral forms exist, with bilateral involvement being more common. A genetic susceptibility locus has been identified, with the RNF213 gene (also known as mysterin) on chromosome 17q25.3 being the most significant susceptibility gene, particularly in East Asian populations. Familial cases account for approximately 10-15% of all cases. There is currently no cure for moyamoya disease, and medical therapy alone (such as antiplatelet agents) is generally insufficient to prevent disease progression. The mainstay of treatment is surgical revascularization to restore blood flow to the affected areas of the brain. Surgical options include direct bypass procedures (such as superficial temporal artery to middle cerebral artery anastomosis), indirect revascularization techniques (such as encephaloduroarteriosynangiosis or EDAS, and encephalomyosynangiosis or EMS), or combined approaches. Early diagnosis and timely surgical intervention are critical to reducing the risk of stroke and preserving neurological function. Long-term follow-up is essential, as the disease can progress over time.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Moyamoya disease