Connexin 26

Danielle Mercer1, Fern Tsien2, and Barbara Gordon-Wendt1

1 Department of Communication Disorders, LSUHSC School of Allied Health Professions
2 Department of Genetics, LSUHSC School of Medicine


Connexin 26 is by far the most common cause of nonsyndromic hearing loss.  Of all autosomal recessive causes of nonsyndromic hearing loss, the connexin 26 gene is responsible for about half.  Over 200 different mutations have been identified in this gene.  The most common is called 35delG, and it accounts for about 70% of connexin 26 cases.  Certain populations have high carrier rates, meaning there are a lot of people who carry a mutation in one of their two copies of connexin 26.  These people will not be affected, but they can have an affected child if their mate also has a connexin 26 mutation.  Populations with the highest connexin 26 carrier rates are:  

  • Caucasians (especially those of northern European or Mediterranean descent): 2-3%
  • Ashkenazi Jewish: 4-5%
  • Japanese: 1%

Like most forms of autosomal recessive hearing loss, the hearing loss in connexin 26 has an early onset.  Hearing loss is usually present in early childhood, and may be present at birth.  In many cases, the hearing loss remains stable, but some cases do show a progressive worsening of hearing loss.  The type of hearing loss is sensorineural, but the degree is variable.  Individuals with connexin 26 can have anywhere from mild to profound hearing loss.  The degree of hearing loss can even vary between members of the same family.  Both ears are usually affected to the same degree.


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