CDH23 and Usher syndrome: Recessive mutations of the CDH23 gene (OMIM: 605,516) are responsible for both nonsyndromic deafness 12 (DFNB12, OMIM: 601,386) and Usher syndrome type 1D (USH1D, OMIM: 601,067) (Bolz et al. 2001; Bork et al. 2001a; Astuto et al. 2002).