[A case of Alexander disease suspected juvenile-onset and exacerbating after long stationary state].

We report the case of a 40-year-old woman with Alexander disease. She experienced single seizure as 1-year-old, and became less active after that. Her academic records in elementary school were poor. However, she graduated from junior college and was later employed as a clerk for a short duration. Her parents, who lived with her noticed her apathy when she was 38, and gait disturbance soon after. At the age of 40, she was admitted to a hospital because of a fall and was referred to us. Brain magnetic resonance imaging (MRI) showed significant leukodystrophy with frontal predominance, and cervical MRI revealed mild cervical cord atrophy with dilated central canal. We performed genetic analysis and found the R79H variant of the gene encoding the glial fibrillary acidic protein. The patient was diagnosed with Alexander disease and suspedted juvenile-onset on the basis of the genetic analysis and MRI findings. Patients with juvenile Alexander disease have been previously reported to have variable survival, ranging from the early teens to the 20's and 30's. Our patient may suggest that natural history of this disease is more variable than previously thought.