Increased levels of GFAP expression are associated with more severe reactive gliosis in a variety of neuropathological conditions and in gliomas (43, 44); cell pathology studies may reveal inclusion bodies—Rosenthal fibers (5)—containing ubiquitinated GFAP aggregates; these inclusion bodies have been observed in syringomyelia, multiple sclerosis (45), and certain subtypes of glioma as well as in AxD. This evidence concerns the gene GFAP and Alexander disease.