The case of a 6-year-old girl with typical absence epilepsy associated with moyamoya disease (MMD) is reported from the Department of Neurosurgery, Kyoto University Graduate School of Medicine, Japan. The child had suffered from recurrent syncope, approximately five times a day for one year, prior to the onset of absence. At 4 years of age she developed episodes of bilateral weakness of her legs, induced by hyperventilation. An EEG revealed a typical bilateral synchronous 3-Hz spike-and-wave discharge induced by hyperventilation. With high-dose sodium valproate (1800 mg daily) seizures increased in frequency to 10 times daily. An MRI showed a small infarction in the left frontal lobe, and cerebral angiography revealed stenoocclusion of terminal portions of both internal carotid arteries and moyamoya vessels at the base of the brain. Antiplatelet therapy with aspirin was started, and decreased regional cerebral blood flow on SPECT and decreased cerebrovascular reserve were demonstrated in bilateral frontal lobes, presurgically. Following bilateral superficial temporal artery-middle cerebral artery anastomoses, the patient responded to treatment with sodium valproate and aspirin, and she had been free of seizures and transient ischemic attacks for more than 2 years at follow-up. An EEG with hyperventilation after withdrawal of medication showed no bursts of spike-and-wave. This is the first reported case of absence epilepsy associated with MMD. 
COMMENT. Moyamoya disease should be considered in the diagnosis of refractory absence epilepsy in Japan, but the prevalence is extremely low. In this case, the preceding syncopal episodes were explained by transient ischemic attacks, and ischemia in the frontal lobes enhanced by hyperventilation was probably related to the occurrence of absence seizures. A possible genetic factor was omitted from the report.