Moyamoya syndrome with protein S deficiency.

Moyamoya disease is a cerebrovascular disease with progressive occlusion of both internal carotid arteries and of their branches and formation of a new vascular network at the base of the brain. Because of the angiographic appearance, it is named as moyamoya. The clinical features are cerebral ischaemia, recurrent transient ischaemic attacks, sensorimotor paralysis, convulsions and migraine-like headaches. A 10-year-old child who acutely developed hemiparesis, weakness and aphasia was found to have moyamoya disease and heterozygous protein S deficiency. This case shows us that during the thromboembolic events the coexistence of protein S deficiency and moyamoya should be investigated.