USH2A and Usher syndrome: Usher syndrome is heterogenous, both in terms of clinical presentation and genetic origin, with a number of diverse genes known to carry pathogenic mutations (Type 1: MYO7A, USH1C, PCDH15, CDH23, USH1G, and CIB2; Type 2: USH2A, ADGRV1, and WHRN; Type 3: CLRN1) [85,86].