Previous studies using animal models showed that while GFAPgfap KOs exhibited relatively normal phenotypes (10, 11, 12, 13, 14), transgenic mice engineered to overexpress normal human gfap exhibited a fatal phenotype with their astrocytes containing abundant protein aggregates (15) that were similar to the Rosenthal fibers (RFs) of Alexander disease (AxD). This evidence concerns the gene GFAP and Alexander disease.