Familial occurrence of moyamoya disease. Magnetic resonance angiography as a screening test for high-risk subjects.

The authors report four cases of familial occurrence of moyamoya disease. Although the pathogenesis of moyamoya disease is not clear, there is extensive evidence that this disease has a tendency to show multifactorial inheritance. Therefore, a screening test for those at high risk, i.e., who have a moyamoya patient among their blood relatives, is clinically important. Magnetic resonance angiography (MRA) successfully revealed abnormal findings specific to moyamoya disease in members of the four probands families. MRA is a powerful and noninvasive way of detecting individuals at high risk of developing moyamoya disease.