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Connexin 26 DNA Sequencing Test

Athena Diagnostics, Inc. is pleased to offer the Connexin 26 DNA Sequencing Test, which analyzes the entire coding region of the Connexin 26 gene (GJB2), as well as the exon 1 donor splice junction.

  • Sequencing the entire gene is critical since at least 62 different disease-causing mutations have been identified on the Connexin 26 gene.1
  • Splice junction analysis is important for detecting all disease-causing mutations in Connexin 26. 35delG, the most common mutation, is found in approximately 66% of patients.2
  • Other mutations account for approximately 30-32%. The frequency of disease-causing mutations has been correlated with ethnic background.
    • 167delT is prevalent in Ashkenazi Jews 3
    • R143W is prevalent in Africans3
    • 235delC is prevalent in Asians3
  • Hearing loss is one of the most frequent hereditary defects. Mutations in the Connexin 26 gene account for up to 50% of all cases of genetic hearing loss. 4,5
  • Early diagnosis allows for early intervention. Hearing impairment should be recognized as early as possible, since it is generally regarded that the most important period for language and speech development is the first three years of life.
  • Delayed diagnosis of hearing loss in infants may have a harmful effect on social, emotional, cognitive, and academic development.6
  • Identification of your patient’s specific mutation provides important information for genetic counseling, including prognosis and recurrence risk.
  • A positive diagnosis can help rule out other diseases, including Ushers Syndrome.

References

  1. Rabionet R, Gasparini P, Estivill X. Connexins and deafness Homepage, www.iro.es/cx26deaf.html. 2001.
  2. Smith, RJH et al., Nonsyndromic Hereditary Hearing Loss and Deafness, DFNB1 (Connexin 26). www.geneclinic.org/profiles/dfnb2/details.html
  3. Kelsell, David P. Connexin Mutations in Skin Disease and Hearing Loss. Am. J. Genet 2001; 68:000-000.
  4. Denoyelle F, et al., Connexin 26 gene linked to a dominant deafness. Nature 1998; 393:319-320.
  5. Nance, W.E. Relation between choice of partner and high frequency of connexin-26 deafness. The Lancet 2000; 356:500-01
  6. Early Identification of Hearing Impairment in Infants and Young Children. NIH Consensus Statement Online 1993 Mar 1-3; 11:(1):1-24.

 
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