ABCA4 and severe early-childhood-onset retinal dystrophy: STGD and dry AMD have significant overlap in the clinical, molecular, and genetic phenotypes such as formation of deposits in the subretinal region, RPE cell damage, perturbations in the complement pathway and ATP Binding Cassette Subfamily A Member 4 (ABCA4) variants associated with each disease [13, 15–17, 26, 30–38].