Biallelic disease-causing variants in GUCY2D are usually associated with Leber's congenital amaurosis (LCA); however, this study illustrates the phenotypic variability of GUCY2D retinopathies in association with variants not biochemically dissimilar to those causing LCA and highlights the complexity of RetGC1 regulation in rod and cone photoreceptor function. This evidence concerns the gene GUCY2D and Leber congenital amaurosis.