Chaib et al. (1996) reviewed the frequency and inheritance of congenital isolated deafness and causes for difficulties associated with mapping of deafness genes. They noted that in the U.S., deafness affects 1 in 1000 children at birth or ... Chaib et al. (1996) reviewed the frequency and inheritance of congenital isolated deafness and causes for difficulties associated with mapping of deafness genes. They noted that in the U.S., deafness affects 1 in 1000 children at birth or during infancy. About 75% of the inherited forms of congenital isolated deafness have an autosomal recessive mode of transmission.
Chaib et al. (1996) described a consanguineous Sunni family with profound prelingual sensorineural hearing impairment living in an isolated village in Syria.
Wagatsuma et al. (2007) reported 5 unrelated Japanese families with DFNB12. All patients had ... Chaib et al. (1996) described a consanguineous Sunni family with profound prelingual sensorineural hearing impairment living in an isolated village in Syria. Wagatsuma et al. (2007) reported 5 unrelated Japanese families with DFNB12. All patients had a similar phenotype, with moderate to profound high-frequency progressive sensorineural hearing loss. The average hearing loss was 84.0 dB. Vestibular function was normal.
Nonsyndromic DFNB12 deafness is associated with CDH23 missense mutations that are presumed to be hypomorphic alleles with sufficient residual activity for retinal and vestibular function, but not for auditory cochlear function. In contrast, homozygous nonsense, frameshift, splice site ... Nonsyndromic DFNB12 deafness is associated with CDH23 missense mutations that are presumed to be hypomorphic alleles with sufficient residual activity for retinal and vestibular function, but not for auditory cochlear function. In contrast, homozygous nonsense, frameshift, splice site and some missense mutations of CDH23, or a combination of these USH1D alleles in a compound heterozygote, cause USH1D. Schultz et al. (2011) identified 12 different homozygous CDH23 missense mutations, including 8 novel mutations, in 13 families with DFNB12. All were missense, except 1 in-frame deletion. Ten different homozygous mutations were found in 14 families and 1 singleton with USH1D. These latter mutations were mostly nonsense, frameshift, or splice site mutations, but there was 1 in-frame deletion and 2 missense mutations. Affected individuals in 3 additional families were found to carry compound heterozygous mutations in the CDH23 gene, with the different alleles being associated with either DFNB12 or USH1D. Based on the phenotypes within families, the results indicated that USH1D occurs only when there are 2 USH1D alleles in trans. In contrast, when there is a DFNB12 allele in trans with a USH1D allele, the phenotype is DFNB12. The findings indicated that a DFNB12 allele is phenotypically dominant to a USH1D allele, and can preserve normal retinal and vestibular function even in the presence of a USH1D allele. Schultz et al. (2011) noted the implications for genetic counseling.
Bork et al. (2001) demonstrated that DFNB12 is caused by mutations in the CDH23 gene (see, e.g., 605516.0005; 605516.0006).
Wagatsuma et al. (2007) identified 4 different missense mutations in the CDH23 gene (see, e.g., 605516.0014 and ... Bork et al. (2001) demonstrated that DFNB12 is caused by mutations in the CDH23 gene (see, e.g., 605516.0005; 605516.0006). Wagatsuma et al. (2007) identified 4 different missense mutations in the CDH23 gene (see, e.g., 605516.0014 and 605516.0015) in 6 Japanese patients from 5 families with autosomal recessive hearing loss. All 4 mutations were found in the extracellular domain of the protein. The findings indicated that mutations in the CDH23 gene may account for about 5% of nonsyndromic hearing loss in the Japanese population.