In patients with both visual and hearing impairments, the biallelic disease-causing mutation rate was assessed for each Usher gene to propose a classification by frequency: USH2A: 50% (341/684) of patients, MYO7A: 21% (144/684), CDH23: 6% (39/684), ADGRV1: 5% (35/684), PCDH15: 3% (21/684), USH1C: 2% (17/684), CLRN1: 2% (14/684), USH1G: 1% (9/684), WHRN: 0.4% (3/684), PDZD7 0.1% (1/684), CIB2 (0/684).
Although a digenic inheritance pattern of hearing impairment has been reported for heterozygous missense variants of ATP2B2 and CDH23, our findings indicate a monogenic cause of hearing impairment in cases with loss-of-function variants of ATP2B2.
Several studies have been carried out to understand the role of Cadherin-23 in the hearing mechanism and defects in the CDH23 have been associated with hearing impairment resulting from defective or absence of tip links.
Linear regression analysis was used to evaluate progression of hearing impairment, and the degree of hearing impairment of DFNB12 was compared with that found for USH1D.
Autosomal recessive nonsyndromal profound childhood deafness in a large pedigree. Audiometric features of the affected persons and the obligate carriers.