Dystonia, myoclonus, and encephalopathy in a single patient: A rare association of moyamoya.

Moyamoya disease (MMD) is a rare neurovascular disorder which pathologically, is a chronic cerebrovasculopathy. It is characterized by stenosis of the internal carotid artery (ICA) and the main branches within the circle of Willis with consecutive development of collateral vessels. There are a few cases in the literature which have described movement disorders as a manifestation of MMD; however these have been uncommonly reported in cases of moyamoya syndrome (MMS). We present a 10-year-old boy with dystonia, myoclonus and encephalopathy like features. These features in association with moyamoya, are rarely described.