Although levels of full-length GFAPs were not consistently altered in AxD samples (Fig. 1E), a dramatic increase in high molecular weight (HMW) GFAP species were detected in six type I AxD cases (Fig. 1C, lanes 2, 6, 8, 9, 11, and 12), representing the youngest of the 13 patients analyzed. This evidence concerns the gene GFAP and Alexander disease.