Mutant ELOVL4 causes juvenile macular degeneration in autosomal dominant Stargardt’s disease (STGD3), with loss of central vision, progressive degeneration of the macula and peripheral retina18–20, 22–28, and early functional defects in RPE cells and PRCs29. The gene discussed is ELOVL4; the disease is severe early-childhood-onset retinal dystrophy.