The largest number of pathogenic variants were found in ABCA4 (Stargardt disease; OMIM 248200; n = 528), SI (sucrase-isomaltase deficiency; OMIM 222900; n = 494), HSPG2 (Schwartz–Jampel syndrome; OMIM 255800; n = 438) and CFTR (cystic fibrosis; n = 408), while 18 genes harbored less than ten pathogenic variants (Fig. 1d and Supplementary Data 2). This evidence concerns the gene HSPG2 and Stargardt disease.