To further explore the therapeutic potential of genome editing for the treatment of WD, we investigated AAV-mediated delivery of promoterless ATP7BΔ1-4 in the toxic-milk mouse from The Jackson Laboratory (Atp7btx-J), which carries a spontaneous missense pathogenic variant in Atp7b resulting in a glycine-to-aspartate change at amino acid position 712 (11, 12). The gene discussed is ATP7B; the disease is Wilson disease.