Gyrate Atrophy of the Choroid and Retina (GACR) currently lacks any effective treatment and a highly restricted, yet cumbersome, low-arginine diet is the only available therapeutic option. In our work, we found that replacement of ornithine-aminotransferase (OAT) activity in the liver lowers ornithine concentrations in the blood and the eye, thus improving retinal structure and function (Boffa et al, 2023).