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Genetics Home Reference: your guide to understanding genetic conditions
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GJB6

Reviewed February 2016

What is the official name of the GJB6 gene?

The official name of this gene is “gap junction protein beta 6.”

GJB6 is the gene's official symbol. The GJB6 gene is also known by other names, listed below.

What is the normal function of the GJB6 gene?

The GJB6 gene provides instructions for making a protein called gap junction beta 6, more commonly known as connexin 30. Connexin 30 is a member of the connexin protein family. Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and signaling molecules between adjoining cells. The size of the gap junction and the types of particles that move through it are determined by the particular connexin proteins that make up the channel. Gap junctions made with connexin 30 transport potassium ions and certain small molecules.

Connexin 30 is found in several different tissues throughout the body, including the brain, inner ear, skin (especially the palms of the hands and soles of the feet), hair follicles, and nail beds. Because of its presence in the inner ear, researchers are interested in this protein's role in hearing. Hearing requires the conversion of sound waves to electrical nerve impulses. This conversion involves many processes, including maintenance of the proper level of potassium ions in the inner ear. Some studies indicate that gap junctions made with connexin 30 help to maintain the correct level of potassium ions.

Does the GJB6 gene share characteristics with other genes?

The GJB6 gene belongs to a family of genes called GJ (gap junction proteins (connexins)).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.

How are changes in the GJB6 gene related to health conditions?

Clouston syndrome - caused by mutations in the GJB6 gene

At least four GJB6 gene mutations have been identified in people with a skin disorder called Clouston syndrome, which is also known as hidrotic ectodermal dysplasia 2. Characteristics of Clouston syndrome include fingernail abnormalities, hair loss, and thickened skin on the palms of the hands and soles of the feet. The GJB6 gene mutations that cause Clouston syndrome change single protein building blocks (amino acids) in the connexin 30 protein. Although the effects of these mutations are not fully understood, they lead to abnormalities in the growth, division, and maturation of cells in the hair follicles, nails, and skin.

nonsyndromic hearing loss - caused by mutations in the GJB6 gene

Researchers have identified a few GJB6 gene mutations in individuals with nonsyndromic hearing loss, which is loss of hearing that is not associated with other signs and symptoms. Mutations in this gene cause a form of nonsyndromic hearing loss called DFNA3. This form of hearing loss can either be present before a child learns to speak (prelingual) or begin after a child learns to speak (postlingual). The hearing loss ranges from mild to profound, becomes more severe over time, and particularly affects the ability to hear high-frequency sounds.

At least two GJB6 gene mutations have been reported to cause DFNA3. Each of these mutations changes a single amino acid in connexin 30. The mutations are described as "dominant negative" because they lead to an abnormal version of connexin 30 that appears to block the formation of functional gap junctions. A shortage of these channels may alter the level of potassium ions in the inner ear, which would disrupt the conversion of sound waves to nerve impulses.

Where is the GJB6 gene located?

Cytogenetic Location: 13q12

Molecular Location on chromosome 13: base pairs 20,221,962 to 20,232,395

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (http://www.ncbi.nlm.nih.gov/gene/10804))

The GJB6 gene is located on the long (q) arm of chromosome 13 at position 12.

The GJB6 gene is located on the long (q) arm of chromosome 13 at position 12.

More precisely, the GJB6 gene is located from base pair 20,221,962 to base pair 20,232,395 on chromosome 13.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about GJB6?

You and your healthcare professional may find the following resources about GJB6 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the GJB6 gene or gene products?

  • CX30
  • CXB6_HUMAN
  • DFNA3
  • ED2
  • EDH
  • gap junction protein, beta 6
  • gap junction protein, beta 6, 30kDa
  • HED

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding GJB6?

acids ; amino acid ; channel ; connexin ; dysplasia ; gap junctions ; gene ; ions ; postlingual ; potassium ; prelingual ; protein ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References

  • Baris HN, Zlotogorski A, Peretz-Amit G, Doviner V, Shohat M, Reznik-Wolf H, Pras E. A novel GJB6 missense mutation in hidrotic ectodermal dysplasia 2 (Clouston syndrome) broadens its genotypic basis. Br J Dermatol. 2008 Dec;159(6):1373-6. doi: 10.1111/j.1365-2133.2008.08796.x. Epub 2008 Aug 19. (http://www.ncbi.nlm.nih.gov/pubmed/18717672?dopt=Abstract)
  • Fujimoto A, Kurban M, Nakamura M, Farooq M, Fujikawa H, Kibbi AG, Ito M, Dahdah M, Matta M, Diab H, Shimomura Y. GJB6, of which mutations underlie Clouston syndrome, is a potential direct target gene of p63. J Dermatol Sci. 2013 Feb;69(2):159-66. doi: 10.1016/j.jdermsci.2012.11.005. Epub 2012 Nov 16. (http://www.ncbi.nlm.nih.gov/pubmed/23219093?dopt=Abstract)
  • Gene Review: Hidrotic Ectodermal Dysplasia 2 (http://www.ncbi.nlm.nih.gov/books/NBK1200)
  • Gene Review: Nonsyndromic Hearing Loss and Deafness, DFNA3 (http://www.ncbi.nlm.nih.gov/books/NBK1536)
  • Kibar Z, Dubé MP, Powell J, McCuaïg C, Hayflick SJ, Zonana J, Hovnanian A, Radhakrishna U, Antonarakis SE, Benohanian A, Sheeran AD, Stephan ML, Gosselin R, Kelsell DP, Christianson AL, Fraser FC, Der Kaloustian VM, Rouleau GA. Clouston hidrotic ectodermal dysplasia (HED): genetic homogeneity, presence of a founder effect in the French Canadian population and fine genetic mapping. Eur J Hum Genet. 2000 May;8(5):372-80. (http://www.ncbi.nlm.nih.gov/pubmed/10854098?dopt=Abstract)
  • Lamartine J, Munhoz Essenfelder G, Kibar Z, Lanneluc I, Callouet E, Laoudj D, Lemaître G, Hand C, Hayflick SJ, Zonana J, Antonarakis S, Radhakrishna U, Kelsell DP, Christianson AL, Pitaval A, Der Kaloustian V, Fraser C, Blanchet-Bardon C, Rouleau GA, Waksman G. Mutations in GJB6 cause hidrotic ectodermal dysplasia. Nat Genet. 2000 Oct;26(2):142-4. (http://www.ncbi.nlm.nih.gov/pubmed/11017065?dopt=Abstract)
  • Marlin S, Feldmann D, Blons H, Loundon N, Rouillon I, Albert S, Chauvin P, Garabédian EN, Couderc R, Odent S, Joannard A, Schmerber S, Delobel B, Leman J, Journel H, Catros H, Lemarechal C, Dollfus H, Eliot MM, Delaunoy JL, David A, Calais C, Drouin-Garraud V, Obstoy MF, Goizet C, Duriez F, Fellmann F, Hélias J, Vigneron J, Montaut B, Matin-Coignard D, Faivre L, Baumann C, Lewin P, Petit C, Denoyelle F. GJB2 and GJB6 mutations: genotypic and phenotypic correlations in a large cohort of hearing-impaired patients. Arch Otolaryngol Head Neck Surg. 2005 Jun;131(6):481-7. (http://www.ncbi.nlm.nih.gov/pubmed/15967879?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/10804)
  • Nickel R, Forge A. Gap junctions and connexins in the inner ear: their roles in homeostasis and deafness. Curr Opin Otolaryngol Head Neck Surg. 2008 Oct;16(5):452-7. doi: 10.1097/MOO.0b013e32830e20b0. Review. (http://www.ncbi.nlm.nih.gov/pubmed/18797288?dopt=Abstract)
  • Xu J, Nicholson BJ. The role of connexins in ear and skin physiology - functional insights from disease-associated mutations. Biochim Biophys Acta. 2013 Jan;1828(1):167-78. doi: 10.1016/j.bbamem.2012.06.024. Epub 2012 Jul 13. Review. (http://www.ncbi.nlm.nih.gov/pubmed/22796187?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: February 2016
Published: February 8, 2016