Mutation of CDH23, encoding a new member of the cadherin gene family, causes Usher syndrome type 1D.

Abstract

Usher syndrome type I (USH1) is an autosomal recessive disorder characterized by congenital sensorineural hearing loss, vestibular dysfunction and visual impairment due to early onset retinitis pigmentosa (RP). So far, six loci (USH1A-USH1F) have been mapped, but only two USH1 genes have been identified: MYO7A for USH1B and the gene encoding harmonin for USH1C. We identified a Cuban pedigree linked to the locus for Usher syndrome type 1D (MIM 601067) within the q2 region of chromosome 10). Affected individuals present with congenital deafness and a highly variable degree of retinal degeneration. Using a positional candidate approach, we identified a new member of the cadherin gene superfamily, CDH23. It encodes a protein of 3,354 amino acids with a single transmembrane domain and 27 cadherin repeats. In the Cuban family, we detected two different mutations: a severe course of the retinal disease was observed in individuals homozygous for what is probably a truncating splice-site mutation (c.4488G-->C), whereas mild RP is present in individuals carrying the homozygous missense mutation R1746Q. A variable expression of the retinal phenotype was seen in patients with a combination of both mutations. In addition, we identified two mutations, Delta M1281 and IVS51+5G-->A, in a German USH1 patient. Our data show that different mutations in CDH23 result in USH1D with a variable retinal phenotype. In an accompanying paper, it is shown that mutations in the mouse ortholog cause disorganization of inner ear stereocilia and deafness in the waltzer mouse.

• Authors: H Bolz, B von Brederlow, A Ramírez, E C Bryda, K Kutsche, H G Nothwang, M Seeliger, M del C-Salcedó Cabrera, M C Vila, O P Molina, A Gal, C Kubisch
• Journal: Nature genetics (Nat Genet) Vol. 27 Issue 1 Pg. 108-12 (Jan 2001) ISSN: 1061-4036 [Print] United States
• PMID: 11138009 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• CDH23 protein, human
• Cadherin Related Proteins
• Cadherins
• RNA Splice Sites
• RNA, Messenger

Topics

• Alternative Splicing (genetics)
• Amino Acid Sequence
• Animals
• Base Sequence
• Cadherin Related Proteins
• Cadherins (chemistry, genetics, metabolism)
• Cloning, Molecular
• Consensus Sequence (genetics)
• Cuba
• DNA Mutational Analysis
• Exons (genetics)
• Female
• Genotype
• Germany
• Hearing Loss, Sensorineural (genetics)
• Humans
• Male
• Molecular Sequence Data
• Multigene Family (genetics)
• Mutation (genetics)
• Pedigree
• Phenotype
• RNA Splice Sites (genetics)
• RNA, Messenger (analysis, genetics)
• Reverse Transcriptase Polymerase Chain Reaction
• Syndrome