TTR and Leber congenital amaurosis: CRISPR-based gene therapy has shown promise in sickle cell disease by correcting the mutation in hematopoietic stem cells ex vivo (Frangoul et al., 2021) and in vivo in Leber congenital amaurosis (LCA) by deleting delete the dominantly inherited intronic IVS26 loss-of-function mutation (Maeder et al., 2019) and in transthyretin amyloidosis by disrupting the disease-causing allele (Gillmore et al., 2021).