Genotypic and phenotypic factors influencing the rate of progression in ABCA-4-related Stargardt disease

Introduction: Stargardt disease (STGD) is heterogeneous in terms of severity and rate of progression. New advancements in genetic testing and retinal imaging have improved prognostication in the disease. Areas covered: A PubMed-based search was carried out using the terms ‘Stargardt dystrophy’, ‘Stargardt disease’, ‘Fundus flavimaculatus’, and ‘ABCA4’. All studies published in English up to August 2020 were reviewed. Data from international multicenter trials were also considered in the discussion. Expert opinion: Genotype-phenotype correlations represent a challenge in STGD, as other epigenetic and environment modifiers participate in defining the clinical outcome and the long-term prognosis. Earlier age of onset and deleterious ABCA4 variants are the main determinants of severe progression. Quantitative imaging approaches are potentially useful for following-up STGD patients. Non-invasive biomarkers are needed to predict the natural history of the disease or drug effectiveness in future therapeutic trials.