Moyamoya disease

About moyamoya disease

This disease occurs when the large arteries carrying nutrients to the brain become blocked, causing fine blood vessels to develop in the surrounding area to compensate for the lack of blood flow. The name "moyamoya disease" comes from the fact that these collateral vessels have the appearance of a puff of smoke ("moyamoya" in Japanese). There are a number of disorders with Japanese names in common use worldwide, but in most cases these are named after their discoverers (such as Kawasaki disease and Hashimoto disease), and use of a descriptive term such as moyamoya for the name of a disease is unusual. The reason for the blockage of these large blood vessels is still not understood. This disorder is rare in Westerners and common among Asians, with a yearly incidence of around 0.35/100,000 people, but an increasing number of asymptomatic cases of moyamoya disease are being discovered during regular brain checkups, and its likelihood is therefore also increasing. Moyamoya disease is somewhat more common in women, and frequency is known to peak in two different ages groups: 5-10 years; and 30-50 years. Recently, however, a decline in the number of pediatric patients and an increase among adult patients has meant that these two age-group peaks are less pronounced than previously noted. The rate of familial onset, such as two sisters or a mother and daughter both developing the disease, is 10%.

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