GFAP and Parkinson disease: Analysis of GFAP labeling in both sexes and in NPD (Fig. 4a, b, e, g) and PD cases (Fig. 4c, d, f, h) using the area fraction method demonstrated a significant increase in diseased compared to non-diseased brains (unpaired two-tailed t-test, t25 = 2.394, p = 0.0245) (Fig. 4i).