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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 2011

What is the official name of the IL1A gene?

The official name of this gene is “interleukin 1 alpha.”

IL1A is the gene's official symbol. The IL1A gene is also known by other names, listed below.

What is the normal function of the IL1A gene?

The IL1A gene provides instructions for making a protein called interleukin-1 alpha. Interleukins are a group of proteins that are made primarily in immune system cells. They are involved in cell-to-cell communication and have a wide variety of functions within the immune system. Interleukin-1 alpha is described as "pro-inflammatory" because it stimulates the activity of genes involved in inflammation and immunity. This protein plays a critical role in protecting the body from foreign invaders such as bacteria and viruses. It is also involved in bone resorption, the breakdown and removal of bone tissue that is no longer needed.

Interleukin-1 alpha is initially produced as a relatively long protein that is trapped within cells. Another protein, called calpain, cuts (cleaves) this precursor protein to create a shorter, mature version of interleukin-1 alpha. The shorter form of this protein is secreted by immune system cells to influence the functions of other cells.

Does the IL1A gene share characteristics with other genes?

The IL1A gene belongs to a family of genes called endogenous ligands (endogenous ligands). It also belongs to a family of genes called IL (interleukins and interleukin receptors).

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 IL1A gene related to health conditions?

ankylosing spondylitis - associated with the IL1A gene

Several variations (polymorphisms) in the IL1A gene have been found to influence the risk of ankylosing spondylitis. Each of these variations changes a single protein building block (amino acid) in interleukin-1 alpha. It is unclear how these variations alter the protein's function. Studies suggest that the effects of IL1A variations are probably related to the role of interleukin-1 alpha in promoting inflammation. Other genetic and environmental factors, many of which are unknown, also affect the chance of developing ankylosing spondylitis.

other disorders - associated with the IL1A gene

Variations in the IL1A gene have been studied as potential risk factors for several other disorders associated with abnormal inflammation. These include chronic gum (periodontal) disease, a progressive bone infection known as chronic osteomyelitis, and an eye disease called open-angle glaucoma.

The most well-studied variation affecting the IL1A gene is a change in a single DNA building block (nucleotide) in a region of regulatory DNA near the start of the gene (written as IL1A-889 C>T). This variation affects the production of interleukin-1 alpha within cells. Researchers have also identified a second common variation in the IL1A gene, written as IL1A+4845 G>T, which changes a single nucleotide in the gene. This variation likely affects the sensitivity of interleukin-1 alpha to cleavage by calpain.

It is unclear how changes in the IL1A gene influence the risk of inflammatory disorders. Studies suggest that the effects of IL1A variations are probably related to the role of interleukin-1 alpha in promoting inflammation. Other genetic and environmental factors also likely affect the chance of developing these complex disorders.

Where is the IL1A gene located?

Cytogenetic Location: 2q14

Molecular Location on chromosome 2: base pairs 112,773,915 to 112,785,394

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

The IL1A gene is located on the long (q) arm of chromosome 2 at position 14.

The IL1A gene is located on the long (q) arm of chromosome 2 at position 14.

More precisely, the IL1A gene is located from base pair 112,773,915 to base pair 112,785,394 on chromosome 2.

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

Where can I find additional information about IL1A?

You and your healthcare professional may find the following resources about IL1A 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 IL1A gene or gene products?

  • hematopoietin-1
  • IL1
  • IL-1A
  • IL-1 alpha
  • IL1F1
  • Interleukin-1 alpha
  • interleukin 1, alpha
  • preinterleukin 1 alpha
  • pro-interleukin-1-alpha

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

What glossary definitions help with understanding IL1A?

amino acid ; bacteria ; breakdown ; cell ; chronic ; cytokine ; dendritic cell ; DNA ; gene ; glaucoma ; idiopathic ; immune system ; infection ; inflammation ; macrophage ; monocyte ; nucleotide ; osteomyelitis ; precursor ; Pro ; protein ; risk factors ; sensitivity ; spondylitis ; tissue

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


  • Asensi V, Alvarez V, Valle E, Meana A, Fierer J, Coto E, Carton JA, Maradona JA, Paz J, Dieguez MA, de la Fuente B, Moreno A, Rubio S, Tuya MJ, Sarasúa J, Llames S, Arribas JM. IL-1 alpha (-889) promoter polymorphism is a risk factor for osteomyelitis. Am J Med Genet A. 2003 Jun 1;119A(2):132-6. (
  • Brionez TF, Reveille JD. The contribution of genes outside the major histocompatibility complex to susceptibility to ankylosing spondylitis. Curr Opin Rheumatol. 2008 Jul;20(4):384-91. doi: 10.1097/BOR.0b013e32830460fe. Review. (
  • Dinarello CA. Biologic basis for interleukin-1 in disease. Blood. 1996 Mar 15;87(6):2095-147. Review. (
  • Graves DT, Cochran D. The contribution of interleukin-1 and tumor necrosis factor to periodontal tissue destruction. J Periodontol. 2003 Mar;74(3):391-401. Review. (
  • Kawaguchi Y, Tochimoto A, Hara M, Kawamoto M, Sugiura T, Saito S, Kamatani N. Contribution of single nucleotide polymorphisms of the IL1A gene to the cleavage of precursor IL-1alpha and its transcription activity. Immunogenetics. 2007 Jun;59(6):441-8. Epub 2007 Apr 18. (
  • Lee S, Temple S, Roberts S, Price P. Complex effects of IL1A polymorphism and calpain inhibitors on interleukin 1 alpha (IL-1 alpha) mRNA levels and secretion of IL-1 alpha protein. Tissue Antigens. 2008 Jul;72(1):67-71. doi: 10.1111/j.1399-0039.2008.01052.x. Epub 2008 May 20. (
  • NCBI Gene (
  • Sims AM, Timms AE, Bruges-Armas J, Burgos-Vargas R, Chou CT, Doan T, Dowling A, Fialho RN, Gergely P, Gladman DD, Inman R, Kauppi M, Kaarela K, Laiho K, Maksymowych W, Pointon JJ, Rahman P, Reveille JD, Sorrentino R, Tuomilehto J, Vargas-Alarcon G, Wordsworth BP, Xu H, Brown MA; International Genetics of Ankylosing Spondylitis. Prospective meta-analysis of interleukin 1 gene complex polymorphisms confirms associations with ankylosing spondylitis. Ann Rheum Dis. 2008 Sep;67(9):1305-9. Epub 2007 Dec 6. (
  • Tsezou A, Poultsides L, Kostopoulou F, Zintzaras E, Satra M, Kitsiou-Tzeli S, Malizos KN. Influence of interleukin 1alpha (IL-1alpha), IL-4, and IL-6 polymorphisms on genetic susceptibility to chronic osteomyelitis. Clin Vaccine Immunol. 2008 Dec;15(12):1888-90. doi: 10.1128/CVI.00209-08. Epub 2008 Oct 29. (


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 2011
Published: February 8, 2016