CLN3 and CLN8 disease: This change in promoter has been found to be effective in a preclinical gene therapy study of CLN8 disease and is additionally congruent with the results of a recent preclinical study in which a similar human MECP2 promoter was shown to be efficacious for AAV-mediated gene therapy in a Cln3 mouse model (Bosch et al., 2016; Johnson et al., 2021).