Repeated encephalopathy and hemicerebral atrophy in a patient with familial hemiplegic migraine type 1.

We herein describe a case of a 38-year-old man with familial hemiplegic migraine with a T666M mutation in the electrical potential-dependent calcium ion channel (CACNA1A) gene. His migraine was accompanied by hemiparesis and impaired consciousness. Brain magnetic resonance imaging revealed abnormalities in the right cortical hemisphere. Single-photon emission computed tomography demonstrated a decrease in iomazenil uptake and an increase in (99m)Tc-ethyl cysteinate dimer uptake at the ipsilateral site. Positron emission tomography showed a decrease in 18F-fluorodeoxyglucose uptake in the same area, which later showed atrophic changes. The patient's brain atrophy ceased after treatment with sodium valproate. This case suggests that the progression of brain atrophy can be prevented with adequate prophylaxis.