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Reviewed January 2014

What is the official name of the GJB4 gene?

The official name of this gene is “gap junction protein beta 4.”

GJB4 is the gene's official symbol. The GJB4 gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the GJB4 gene?

The GJB4 gene provides instructions for making a protein called gap junction beta 4, more commonly known as connexin 30.3. This protein is part of the connexin family, a group of proteins that form channels called gap junctions on the surface of cells. Gap junctions open and close to regulate the flow of nutrients, charged atoms (ions), and other signaling molecules from one cell to another. They are essential for direct communication between neighboring cells.

Connexin 30.3 is found in several different tissues, including the outermost layer of the skin (the epidermis). This protein appears to play a role in the growth and maturation of epidermal cells.

Does the GJB4 gene share characteristics with other genes?

The GJB4 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 GJB4 gene related to health conditions?

erythrokeratodermia variabilis et progressiva - caused by mutations in the GJB4 gene

At least seven GJB4 gene mutations have been identified in people with erythrokeratodermia variabilis et progressiva (EKVP), a skin disorder characterized by areas of hyperkeratosis, which is abnormally thickened skin, and temporarily reddened patches called erythematous areas. Each of these mutations changes a single protein building block (amino acid) used to make connexin 30.3. Studies suggest that the abnormal protein can build up in a cell structure called the endoplasmic reticulum (ER), triggering a harmful process known as ER stress. Researchers suspect that ER stress damages and leads to the premature death of cells in the epidermis. This cell death leads to skin inflammation, which appears to underlie the development of erythematous areas. The mechanism by which epidermal damage and cell death contributes to hyperkeratosis is poorly understood.

Where is the GJB4 gene located?

Cytogenetic Location: 1p34.3

Molecular Location on chromosome 1: base pairs 34,759,741 to 34,763,724

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The GJB4 gene is located on the short (p) arm of chromosome 1 at position 34.3.

The GJB4 gene is located on the short (p) arm of chromosome 1 at position 34.3.

More precisely, the GJB4 gene is located from base pair 34,759,741 to base pair 34,763,724 on chromosome 1.

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

Where can I find additional information about GJB4?

You and your healthcare professional may find the following resources about GJB4 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 GJB4 gene or gene products?

  • connexin 30.3
  • connexin-30.3
  • CX30.3
  • EKV
  • gap junction beta-4 protein
  • gap junction protein, beta 4, 30.3kDa

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding GJB4?

amino acid ; cell ; connexin ; endoplasmic reticulum ; epidermis ; ER ; gap junctions ; gene ; inflammation ; ions ; oxygen ; protein ; reactive oxygen species ; stress

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

See also Understanding Medical Terminology.

References (6 links)


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: January 2014
Published: February 1, 2016