Based on clinical, genetic, network, and disease model findings for the founding forms of Usher syndrome, USH1, USH2 and USH3 (see Figs. 4, 5), and those for additional so-called ‘USH-like’ genes, we propose to consider MYO7A, USH1C, PCDH15, CDH23, and USH1G as the only USH1 genes, USH2A, ADGRV1, and WHRN as the only USH2 genes, and CLRN1 as the causal gene for USH3. This evidence concerns the gene PCDH15 and Usher syndrome.