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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed February 2009

What is the official name of the GJA1 gene?

The official name of this gene is “gap junction protein alpha 1.”

GJA1 is the gene's official symbol. The GJA1 gene is also known by other names, listed below.

What is the normal function of the GJA1 gene?

The GJA1 gene provides instructions for making a protein called connexin43, which is one of 21 connexin proteins in humans. Connexins play a role in cell-to-cell communication by forming channels, or gap junctions, between cells. Gap junctions allow for the transport of nutrients, charged particles (ions), and other small molecules that carry necessary communication signals between cells. Connexin43 is found in many human tissues such as the eyes, skin, bone, ears, heart, and brain.

Does the GJA1 gene share characteristics with other genes?

The GJA1 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? ( in the Handbook.

How are changes in the GJA1 gene related to health conditions?

oculodentodigital dysplasia - caused by mutations in the GJA1 gene

More than 45 mutations in the GJA1 gene have been found to cause oculodentodigital dysplasia. Most of these mutations change one protein building block (amino acid) in connexin 43. A different change in the GJA1 gene causes people to have oculodentodigital dysplasia with palmoplantar keratoderma. Palmoplantar keratoderma is a condition that causes skin on the palms and the soles of the feet to become thick, scaly, and calloused. This mutation deletes two DNA building blocks (nucleotides) to create a premature stop signal in the instructions for making connexin43. As a result, an abnormally short, nonfunctional protein is produced.

Channels formed with abnormal connexin 43 proteins are often permanently closed, preventing the transport of any molecules. Some mutations prevent connexin 43 proteins from traveling to the cell surface where they are needed to form channels. These disruptions in channel function impair communication between cells, which is thought to cause the eye, teeth, and finger abnormalities characteristic of oculodentodigital dysplasia.

other disorders - caused by mutations in the GJA1 gene

GJA1 gene mutations have been found to cause deafness in a small number of African Americans. Further research is needed to determine how common GJA1 mutations are among African-Americans and people in other ethnic groups with deafness.

Where is the GJA1 gene located?

Cytogenetic Location: 6q22.31

Molecular Location on chromosome 6: base pairs 121,435,577 to 121,449,744

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The GJA1 gene is located on the long (q) arm of chromosome 6 at position 22.31.

The GJA1 gene is located on the long (q) arm of chromosome 6 at position 22.31.

More precisely, the GJA1 gene is located from base pair 121,435,577 to base pair 121,449,744 on chromosome 6.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about GJA1?

You and your healthcare professional may find the following resources about GJA1 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 GJA1 gene or gene products?

  • connexin43
  • connexin 43
  • CX43
  • Cx43α1
  • gap junction 43 kDa heart protein
  • gap junction protein, alpha 1, 43kDa
  • gap junction protein, alpha-like

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding GJA1?

amino acid ; cell ; channel ; charged particles ; congenital ; connexin ; DNA ; dysplasia ; gap junctions ; gene ; heterotaxy ; ions ; keratoderma ; mutation ; palmoplantar keratoderma ; protein ; syndrome

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


  • Danesh-Meyer HV, Green CR. Focus on molecules: connexin 43--mind the gap. Exp Eye Res. 2008 Dec;87(6):494-5. doi: 10.1016/j.exer.2008.01.021. Epub 2008 Feb 6. Review. (
  • Dasgupta C, Martinez AM, Zuppan CW, Shah MM, Bailey LL, Fletcher WH. Identification of connexin43 (alpha1) gap junction gene mutations in patients with hypoplastic left heart syndrome by denaturing gradient gel electrophoresis (DGGE). Mutat Res. 2001 Aug 8;479(1-2):173-86. (
  • Debeer P, Van Esch H, Huysmans C, Pijkels E, De Smet L, Van de Ven W, Devriendt K, Fryns JP. Novel GJA1 mutations in patients with oculo-dento-digital dysplasia (ODDD). Eur J Med Genet. 2005 Oct-Dec;48(4):377-87. (
  • Hossain MZ, Boynton AL. Regulation of Cx43 gap junctions: the gatekeeper and the password. Sci STKE. 2000 Oct 17;2000(54):pe1. Review. (
  • Laird DW. Closing the gap on autosomal dominant connexin-26 and connexin-43 mutants linked to human disease. J Biol Chem. 2008 Feb 8;283(6):2997-3001. Epub 2007 Dec 18. Review. (
  • Laird DW. Life cycle of connexins in health and disease. Biochem J. 2006 Mar 15;394(Pt 3):527-43. Review. (
  • Liu XZ, Xia XJ, Adams J, Chen ZY, Welch KO, Tekin M, Ouyang XM, Kristiansen A, Pandya A, Balkany T, Arnos KS, Nance WE. Mutations in GJA1 (connexin 43) are associated with non-syndromic autosomal recessive deafness. Hum Mol Genet. 2001 Dec 1;10(25):2945-51. (
  • NCBI Gene (
  • Paznekas WA, Boyadjiev SA, Shapiro RE, Daniels O, Wollnik B, Keegan CE, Innis JW, Dinulos MB, Christian C, Hannibal MC, Jabs EW. Connexin 43 (GJA1) mutations cause the pleiotropic phenotype of oculodentodigital dysplasia. Am J Hum Genet. 2003 Feb;72(2):408-18. Epub 2002 Nov 27. (
  • Shibayama J, Paznekas W, Seki A, Taffet S, Jabs EW, Delmar M, Musa H. Functional characterization of connexin43 mutations found in patients with oculodentodigital dysplasia. Circ Res. 2005 May 27;96(10):e83-91. Epub 2005 May 5. (
  • van Steensel MA, Spruijt L, van der Burgt I, Bladergroen RS, Vermeer M, Steijlen PM, van Geel M. A 2-bp deletion in the GJA1 gene is associated with oculo-dento-digital dysplasia with palmoplantar keratoderma. Am J Med Genet A. 2005 Jan 15;132A(2):171-4. (
  • Vreeburg M, de Zwart-Storm EA, Schouten MI, Nellen RG, Marcus-Soekarman D, Devies M, van Geel M, van Steensel MA. Skin changes in oculo-dento-digital dysplasia are correlated with C-terminal truncations of connexin 43. Am J Med Genet A. 2007 Feb 15;143(4):360-3. (


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? ( in the Handbook.

Reviewed: February 2009
Published: February 1, 2016