C9 and amyotrophic lateral sclerosis: In C9‐HRE‐associated ALS, the presence of RNA foci and DPRs can elicit RNA mediated toxicity (McEachin et al. 2020) or impair nuclear import of transcripts by interacting with the nucleocytoplasmic transport protein Ran GTPase‐activating protein (RanGAP) in C9‐HRE iPSC derived neurons (Zhang et al. 2015).