(a, b) Representative images of γH2AX staining in human postmortem motor cortex sections of controls and ALS patients harboring FUS-R521C or FUS-P525L mutation. Higher magnificent image of arrow pointed cells was shown in the γH2AX and DAPI panels. Note that 48% and 54% of the NeuN+, γH2AX+ cells (white arrow) are morphologically normal and indistinguishable from surrounding NeuN+, γH2AX− cells in FUS-R521C and FUS-P525L brain sections, respectively. While the remaining cells exhibit altered morphology (yellow arrow). Error bar represents SD between slides. 5–6 images per slide, 5 slides each patient (mean ± SEM, ***P<0.001, one-way ANOVA). Scale bar: 20 μm.