Retinal thinning is a key feature of our c9orf72 mutant zebrafish, which is also present in ALS patients that do not otherwise present with ophthalmic disease (Ringelstein et al., 2014; Mukherjee et al., 2017; Cerveró et al., 2021). Here, C9orf72 is linked to amyotrophic lateral sclerosis.