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Reviewed April 2010

What is the official name of the JAG1 gene?

The official name of this gene is “jagged 1.”

JAG1 is the gene's official symbol. The JAG1 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 JAG1 gene?

The JAG1 gene provides instructions for making a protein called Jagged-1, which is involved in an important pathway by which cells can signal to each other. The Jagged-1 protein is inserted into the membranes of certain cells. It connects with other proteins called Notch receptors, which are bound to the membranes of adjacent cells. These proteins fit together like a lock and its key. When a connection is made between the Jagged-1 and Notch proteins, it launches a series of signaling reactions (Notch signaling) affecting cell functions. Notch signaling controls how certain types of cells develop in a growing embryo, especially cells destined to be part of the heart, liver, eyes, ears, and spinal column. The Jagged-1 protein continues to play a role throughout life in the development of new blood cells.

Does the JAG1 gene share characteristics with other genes?

The JAG1 gene belongs to a family of genes called CD (CD molecules).

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 JAG1 gene related to health conditions?

Alagille syndrome - caused by mutations in the JAG1 gene

At least 226 mutations in the JAG1 gene have been identified in people with Alagille syndrome. Most of these mutations result in an abnormally short Jagged-1 protein that is missing the segment that normally spans the cell membrane (the transmembrane domain). Other mutations interfere with proper transport (trafficking) of the protein within the cell, preventing it from reaching the cell membrane. The loss of Jagged-1 protein at the cell membrane precludes its interaction with Notch proteins and prevents cell signaling. The lack of Notch signaling causes errors in development that result in missing or narrowed bile ducts in the liver, heart defects, distinctive facial features, and changes in other parts of the body. People with JAG1 gene mutations may have one or more of these problems. In particular, some affected individuals have a particular combination of heart defects known as tetralogy of Fallot without other signs or symptoms of Alagille syndrome. The type and severity of problems associated with Alagille syndrome may differ even within the same family.

cancers - associated with the JAG1 gene

Increased activity (expression) of the JAG1 gene has been linked to certain cancers, including breast cancer and head and neck tumors. The increased expression of the JAG1 gene may promote the development of new blood vessels that nourish a growing tumor. The altered gene expression may also enhance other cancer-related events such as cell division (proliferation) and the inflammatory response.

Where is the JAG1 gene located?

Cytogenetic Location: 20p12.1-p11.23

Molecular Location on chromosome 20: base pairs 10,637,684 to 10,674,046

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

The JAG1 gene is located on the short (p) arm of chromosome 20 between positions 12.1 and 11.23.

The JAG1 gene is located on the short (p) arm of chromosome 20 between positions 12.1 and 11.23.

More precisely, the JAG1 gene is located from base pair 10,637,684 to base pair 10,674,046 on chromosome 20.

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

Where can I find additional information about JAG1?

You and your healthcare professional may find the following resources about JAG1 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 JAG1 gene or gene products?

  • AGS
  • AHD
  • AWS
  • CD339
  • CD339 antigen
  • HJ1
  • jagged 1 (Alagille syndrome)
  • jagged 1 precursor
  • JAGL1

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 JAG1?

bile ; cancer ; cell ; cell division ; cell membrane ; domain ; embryo ; gene ; gene expression ; ligand ; precursor ; proliferation ; protein ; syndrome ; tetralogy of Fallot ; transmembrane ; tumor

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

See also Understanding Medical Terminology.

References (14 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: April 2010
Published: February 1, 2016