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Reviewed October 2008
What is the official name of the CD40LG gene?
The official name of this gene is “CD40 ligand.”
CD40LG is the gene's official symbol. The CD40LG 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 CD40LG gene?
The CD40LG gene provides instructions for making a protein called CD40 ligand, which is found on the surface of immune system cells known as T cells. CD40 ligand attaches like a key in a lock to its receptor protein, CD40, which is located on the surface of immune system cells known as B cells. B cells are involved in the production of proteins called antibodies or immunoglobulins that help protect the body against infection. There are several classes of antibodies, and each one has a different function in the immune system. B cells are able to mature into the cells that produce immunoglobulin M (IgM) without any signals from other cells. In order for B cells to mature into the cells that produce antibodies of a different class, the CD40 receptor must interact with CD40 ligand. When these two proteins are connected, they trigger a series of chemical signals that instruct the B cell to start making immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin E (IgE).
CD40 ligand is also necessary for T cells to interact with other cells of the immune system, and it plays a key role in T cell differentiation (the process by which cells mature to carry out specific functions).
Does the CD40LG gene share characteristics with other genes?
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 CD40LG gene related to health conditions?
Where is the CD40LG gene located?
Cytogenetic Location: Xq26
Molecular Location on the X chromosome: base pairs 136,648,177 to 136,660,390
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The CD40LG gene is located on the long (q) arm of the X chromosome at position 26.
More precisely, the CD40LG gene is located from base pair 136,648,177 to base pair 136,660,390 on the X chromosome.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about CD40LG?
You and your healthcare professional may find the following resources about CD40LG 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 CD40LG gene or gene products?
See How are genetic conditions and genes named? in the Handbook.
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 CD40LG?
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (8 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.