Most of our knowledge regarding the functions of CDH23, however, comes from studies on hearing and vision, as mutation of CDH23 is known to cause various degrees of hearing impairment and blindness, including Usher Syndrome 1D4, age-related hearing loss, and nonsyndromic deafness (autosomal recessive 12, DFNB12)5. This evidence concerns the gene CDH23 and nonsyndromic deafness.