GFAP and multiple sclerosis: Petzold et al. reported a GFAP concentration of 1.7 (1.1–5.9) (median, range) μg/mg of total protein in cerebral white matter and 0.8 (0.5–1.2) (median, range) μg/mg of total protein in cerebral cortex from five deceased control patients in a study on multiple sclerosis [10].