Severe Early-Childhood-Onset Retinal Dystrophy, also known as retinal dystrophy, early onset severe, is related to stargardt disease 1 and retinitis pigmentosa 20. An important gene associated with Severe Early-Childhood-Onset Retinal Dystrophy is ABCA4 (ATP Binding Cassette Subfamily A Member 4), and among its related pathways/superpathways are Visual phototransduction and Visual Cycle in Retinal Rods. Affiliated tissues include eye and retina, and related phenotypes are nystagmus and visual impairment