GFAP and amyotrophic lateral sclerosis: GFAP was also significantly associated with p62 areal fraction and the proportion of p62‐positive neurons in the spinal cord across all cases (r > 0.8, p ≤ 0.001) and in ALS‐TDP cases only (r > 0.8, p ≤ 0.01), indicating increased reactive astrocytes with autophagy.