GFAP and amyotrophic lateral sclerosis: In addition to the non-cell autonomous effects on motor neurons caused by SOD mutations in astrocytes, ALS-associated mutations induce drastic changes in astrocyte biology, at least in vivo, including reactive astrocytosis, also known as astrogliosis, as evidenced by the increased GFAP expression and process hypertrophy85, , , , –90, and ultimately astrocyte degeneration and apoptosis91.