Data from mice lacking GFAP and vimentin (GFAP−/−Vim−/−) and other experimental modulations of reactive gliosis point to reactive gliosis as protective in ischemic stroke [4,7,8,9], neurotrauma [5,10,11,12], and neurodegenerative diseases [13,14,15]. The gene discussed is GFAP; the disease is neurodegenerative disease.