It will be highly prudent to determine how common retinal degeneration is within other C9ORF72-deficient vertebrate models, such as the mouse or rat (Balendra and Isaacs, 2018; Dong et al., 2021) to determine whether retinal pathology is a universal feature of C9ORF72 loss of function. This evidence concerns the gene C9orf72 and retinal degeneration.