ABCA4 and severe early-childhood-onset retinal dystrophy: In cases clinically classified as MD/STGD, pathogenic variants were demonstrated in 82% (nine of 11) of the probands, with most causal variants (4/9) being localized at ABCA4. In an additional familial MD/STGD case, a novel IFT140 (MIM *614620) truncating defect (p.Gln1418Ter) was demonstrated (Table 2).