GFAP and retinal degeneration: We analysed the onset and progression of the retinal degeneration of both Idh3aE229K/E229K and Idh3a−/E229K mice by immunostaining for glial fibrillary acidic protein (GFAP), the expression of which is a sign of reactive gliosis of the Müller cells and an early indicator of stress within the retina (Eisenfeld et al., 1984).