Early and correct diagnosis is of particular importance for Stargardt disease (STGD1), a common inherited macular dystrophy caused by mutations in the ABCA4 gene, and especially for adult-onset STGD1 (age of onset ≥ 20 years; late-onset STGD1 is a subtype of adult-onset STGD1 if age of onset is 45 years or older). The gene discussed is ABCA4; the disease is severe early-childhood-onset retinal dystrophy.