Moyamoya disease and Brain death I have been recently consulted on the organ transplantation from the brain-death donor with moyamoya disease. In Japan, organ transplantation from the brain-death patient has been rarely performed because there are so many limitations to allow it legally. In addition to medical requirements, "donor card" to express the will to donate the organs is required in advance. Thus, organ transplantation itself (in the patients without moyamoya disease) has been performed only 24 times so far. As for the organ transplantation from the patients with moyamoya disease may occur abroad. Actually, I know such a case (young woman) who developed fatal cerebral hemorrhage in Great Britain. The medical issues in this situation are whether organs in moyamoya patients are suitable for transplantation. In another word, whether pathological changes in the cerebral arteries occur in the other organs such as heart, lung, liver, kidney, etc. Histopathological change in the cerebral arteries is "intimal thickening" of the arterial wall without atherosclerosis or inflammatory change. It is known that the similar pathological change may occur in the arteries of the heart, kidney, spleen, and scalp. However, these changes do not occur all the patients with moyamoya disease. When those changes exist, not all the segments of such arteries show such pathological changes (stenosis or occlusion). For example, if all the scalp arteries have such steno-occlusive changes, surgical anastomosis may lose its role for additional blood supply through the anastomosis because of the occlusion of the scalp (blood supplying) artery. Thus, the incidence of steno-occlusive changes in the organ arteries may be very low, and I believe it is less likely that such pathological changes may cause clinical problem in organ transplantation. Aging of the arteries (atherosclerosis) might be a greater problem in such a situation. It can not be said with certainty that organ transplantation of the patients with moyamoya disease has no clinical problem, but in many cases, it will not cause clinical problems. 2004.2.7