All patients were previously screened and found to have zero (eight samples) or one (one sample) disease-causing mutation in ABCA4. While some of these probands express ocular imaging phenotypes not typically observed in classic STGD, all were diagnosed clinically as having STGD due to the early age at which signs of macular degeneration were initially identified. This evidence concerns the gene ABCA4 and severe early-childhood-onset retinal dystrophy.