Alexander disease (AxD, OMIM 203450) is a rare but fatal central nervous system disease. Three subtypes are distinguished upon the onset age: infantile (under age 2), juvenile (age 2 to 12) and adult (over age 12). The infantile form is the most common subtype while the adult onset the least. All subtypes have been described and present with different clinical manifestations. However, the pathological hallmark of the disease is the accumulation of ubiquitinated intracytoplasmic inclusions in astrocytes, called rosenthal fibers, which are composed of glial fibrillary acidic protein (GFAP), the main intermediate filament of astrocytes [1].