Phenotypic variability of non-syndromic hearing loss in patients heterozygous for both c.35delG of GJB2 and the 342-kb deletion involving GJB6

Hear Res. 2004 Feb;188(1-2):42-6. doi: 10.1016/S0378-5955(03)00346-0.


Mutations in GJB2, encoding the gap junction protein connexin 26, are the most common cause of inherited non-syndromic hearing loss (NSHL), with a broad spectrum of mutations leading to recessive as well as dominant forms. It has been shown that patients who are compound heterozygous for a 342-kb deletion (Delta(GJB6-D13S1830)) involving a large portion of the 5'-part of GJB6, encoding connexin 30, and a GJB2 mutation develop NSHL due to a trait with a digenic pattern of inheritance. We have used a mutation-specific polymerase chain reaction assay to screen NSHL patients for the presence of Delta(GJB6-D13S1830) and identified two families segregating both c.35delG in GJB2 and Delta(GJB6-D13S1830). Remarkably, the severity of hearing loss due to heterozygosity for c.35delG in GJB2 in conjunction with Delta(GJB6-D13S1830) is considerably different in members of the two families, ranging from congenital deafness in one to moderate/severe hearing loss with congenital onset in the other case.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Base Sequence
  • Child
  • Child, Preschool
  • Connexin 26
  • Connexin 30
  • Connexins / genetics*
  • Deafness / genetics*
  • Gap Junctions / genetics*
  • Heterozygote
  • Humans
  • Infant
  • Middle Aged
  • Mutation*
  • Pedigree
  • Phenotype
  • Polymerase Chain Reaction
  • Sequence Deletion


  • Connexin 30
  • Connexins
  • GJB2 protein, human
  • GJB6 protein, human
  • Connexin 26