GFAP and nervous system disorder: In the context of insult, pathogen infection, or neurological disease, astrocytes undergo functionally complex reactive responses (Chiu et al. 2014; Giovannoni and Quintana 2020) that are associated with an increase in glial fibrillary acidic protein (GFAP) gene and protein expression (Crespo-Castrillo et al. 2020; Sofroniew 2020).