Moyamoya syndrome


Moyamoya syndrome is an extremely rare condition characterised by the narrowing of the major arteries (blood vessels that carry oxygenated blood from the heart) to the brain with a group of small extra vessels that are nature’s attempt to overcome the block. Half of all Moyamoya cases are found in children under 10 years of age, with females more affected than males. It is more common in the Japanese population, and usually occurs sporadically (no other family members are affected). Recent work in Japan has identified some genes which appear to be associated with the development of Moyamoya syndrome. The first symptom is often stroke, which may cause paralysis of one side of the body or occasionally seizures. In some children, development slows down or skills may be lost. Magnetic resonance imaging (MRI) scans and cerebral angiography, in which a dye is injected into the arteries of the brain to allow them to be visualised, is the conventional method of diagnosis, and treatment is usually a combination of antiplatelet agents (e.g. aspirin) and surgery. Treatment following a stroke will include physiotherapy, occupational therapy and speech therapy. Children may require extra help in school. Although the direct cause of Moyamoya syndrome is often uncertain, it can be seen in a number of diseases that can affect arteries, including Down syndromesickle cell disorders, and chronic meningitis There is also an association with thyroid disease and connective tissue disorders.


Medical text approved March 2014 by Dr Jenny Fisken (retired), formerly Associate Specialist in Community Paediatrics, North Yorkshire and York PCT.

Is there support?

There is no support group for moyamoya syndrome in the UK.

Families can use Contact’s freephone helpline for advice, information and, where possible, links to other families. To meet other families with disabled children, join Contact’s closed (private) Facebook group.

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