USH2A and Usher syndrome: Usher syndrome is very well characterized at the genetic level, with many alleles known to affect at least 10 genes including MYO7A (MIM:276903), USH1C (MIM:605242), CDH23 (MIM:605516), PCDH15(MIM: 605514), SANS (MIM: 607696), USH2A, VLGR1(MIM: 602851), WRHN (MIM: 607928), USH3A(MIM: 606397), and PDZD7(MIM: 612971) [2],[56],[57].