C9orf72 and amyotrophic lateral sclerosis: In addition, cytoplasmic protein inclusions are present in astrocytes spanning various mutations (Bruijn et al., 1997; Serio et al., 2013; Barton et al., 2020) and iPSC-derived C9orf72-ALS astrocytes contain pathogenic nuclear RNA foci (Figure 3) (Zhao et al., 2020).