Variation in CDH23 has been reported in individuals with Usher syndrome 1 (USH1) and autosomal recessive nonsyndromic hearing loss (ARNSHL); furthermore, the overall evidence that CDH23, when altered, can cause USH1 was expert reviewed by the ClinGen Hearing Loss Working Group (HLWG) and classified as DEFINITIVE. The evidence supporting the association between CDH23 and ARNSHL was also classified as DEFINITIVE by the ClinGen HLWG after primary curation.