Autoimmune GFAP Astrocytopathy is an autoimmune disease in which the immune system of the patient attacks a protein of the nervous system called glial fibrillary acidic protein (GFAP). It was described in 2016 by researchers of the Mayo Clinic in the United States. GFAP is an intermediate filament (IF) protein that is expressed by numerous cell types of the central nervous system (CNS) including astrocytes. The destruction of astrocytes can lead to the development of a glial scar.