What is moyamoya disease?
Moyamoya disease is a rare brain disorder that limits blood flow to the brain. In moyamoya disease, the main arteries supplying blood to the brain get narrow over time, reducing oxygen to the brain and causing strokes. To compensate, the brain forms many tiny blood vessels that on brain scans look wispy and tangled like “puffs of smoke”—moyamoya in Japanese.
Moyamoya disease can be diagnosed in both children and adults and gets worse over time. Without surgery, most people with the condition will have multiple strokes that can cause permanent damage and bleeding in the brain. This damage affects a person’s ability to think and move.
The exact causes of moyamoya disease are not known, but some cases run in families. This suggests that variants (also called mutations) in a group of specific genes cause moyamoya disease. Moyamoya disease symptoms can also be caused by separate health conditions: in these cases, it is called moyamoya syndrome.
Symptoms of moyamoya disease
In children, the first symptom of moyamoya disease is often a type of stroke called a transient ischemic attack (TIA). TIAs, also known as mini-strokes, are short interruptions of blood flow that only last a few minutes. They can cause weakness or paralysis on one side of the body. Symptoms typically go away within a day.
Adults may also experience TIAs from blocked arteries to the brain. But adults with moyamoya disease are more likely than children to have a hemorrhagic stroke, which is caused by bleeding in the brain.
Other symptoms of moyamoya disease can include:
- Headaches
- Seizures
- Uncontrolled movements
- Vision problems
- Trouble with thinking, memory, or concentration
Who is more likely to get moyamoya disease?
Some people are more likely to get moyamoya disease than others. For example, women are more likely to have moyamoya disease than men. Moyamoya disease may be more common in Asian Americans, but people of any race or ethnicity can get it.
Some treatments and conditions may cause moyamoya syndrome. For example, people who have been exposed to radiation therapy in the brain for cancer or other brain disorders may be at higher risk of moyamoya syndrome. Some autoimmune diseases, conditions, and infections can also cause moyamoya disease.
Some cases of moyamoya disease run in families, so people with a close family member with moyamoya disease may also be at risk for having it.
How is moyamoya disease diagnosed and treated?
Diagnosing moyamoya disease
Doctors usually diagnose moyamoya disease by:
- Brain scans: Doctors use special X-ray tests, called angiograms, or magnetic resonance imaging (MRI) scans to see how blood flows through vessels and identify narrow spots.
- Health history: Doctors may ask about other health conditions that could cause moyamoya disease, such as being exposed to radiation to the head and neck. They may also ask whether any family members have been diagnosed with moyamoya disease.
Learn more about neurological diagnostic tests and procedures.
Treating moyamoya disease
Surgery to open narrowed blood vessels is the most effective treatment for moyamoya disease and can reduce the risk of future strokes. Some people don’t have any more strokes or symptoms after surgery. Medicines and healthy lifestyle habits may also help lower overall stroke risk.
What are the latest updates on moyamoya disease?
The National Institutes of Health (NIH), which includes NINDS, is the leading federal funder of research on the brain and nervous system, including disorders such as moyamoya disease. NIH supports new and innovative research to better understand, diagnose, and treat moyamoya disease.
NIH-funded researchers are using brain imaging (MRI and angiograms) to better understand moyamoya disease in people before and after they have surgery. This research may lead to better ways to diagnose and treat moyamoya disease.
Other NIH-funded research is developing a new imaging technique to use before and after surgery. These images may help doctors plan surgeries more precisely as well as test how well blood flow improves in people with moyamoya disease.
For more information on research about moyamoya disease, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.
For research articles and summaries on moyamoya disease, search PubMed, which contains citations from medical journals and other sites.
How can I or my loved one help improve care for people with moyamoya disease?
Consider participating in a clinical trial so clinicians and scientists can learn more about moyamoya disease and related disorders. Clinical research with human study participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of participants are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities. This helps make sure that study results apply to as many people as possible and that treatments will be safe and effective for everyone who will use them.
For information about participating in clinical research, visit the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn more about clinical trials currently looking for people with moyamoya disease at ClinicalTrials.gov, a searchable database of current and past clinical studies and research results.
Where can I find more information about moyamoya disease?
Information may be available from the following sources:
American Heart Association
800-242-8721