Novel mutations in the connexin 26 gene (GJB2) responsible for childhood deafness in the Japanese population

Takayuki Kudo, Katsuhisa Ikeda, Shigeo Kure, Yoichi Matsubara, Takeshi Oshima, Ken Ichi Watanabe, Tetsuaki Kawase, Kuniaki Narisawa, Tomonori Takasaka

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177 Citations (Scopus)


Mutations in the connexin 26 gene (GJB2), which encodes a gap-junction protein and is expressed in the inner ear, have been shown to be responsible for a major part of nonsyndromic hereditary prelingual (early-childhood) deafness in Caucasians. We have sequenced the GJB2 gene in 39 Japanese patients with prelingual deafness (group 1), 39 Japanese patients with postlingual progressive sensorineural hearing loss (group 2), and 63 Japanese individuals with normal hearing (group 3). Three novel mutations were identified in group 1: a single nucleotide deletion (235delC), a 16-bp deletion (176-191 del (16)), and a nonsense mutation (Y136X) in five unrelated patients. The 235delC mutation was most frequently observed, accounting for seven alleles in 10 mutant alleles. Screening of 203 unrelated normal individuals for the three mutations indicated that the carrier frequency of the 235delC mutation was 2/203 in the Japanese population. No mutation was found in group-2 patients. We also identified two novel polymorphisms (E114G and I203T) as well as two previously reported polymorphisms (V27I andV37I). Genotyping with these four polymorphisms allowed normal Japanese alleles to be classified into seven haplotypes. All 235delC mutant alleles identified in four patients resided only on haplotype type 1. These findings indicate that GJB2 mutations are also responsible for prelingual deafness in Japan.

Original languageEnglish
Pages (from-to)141-145
Number of pages5
JournalAmerican journal of medical genetics
Issue number2
Publication statusPublished - 2000 Jan 17


  • Connexin 26
  • GJB2
  • Japanese
  • Mutation
  • Polymorphism
  • Prelingual deafness

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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