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IL1A gene

interleukin 1 alpha

Normal Function

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.

Health Conditions Related to Genetic Changes

Ankylosing spondylitis

Several variations (polymorphisms) in the IL1A gene have been found to influence the risk of ankylosing spondylitis.  This condition is a form of painful, ongoing joint inflammation (chronic inflammatory arthritis) that primarily affects the spine. Each of these variations changes a single protein building block (amino acid) in interleukin-1 alpha. It is not fully known 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.

More About This Health Condition

Idiopathic inflammatory myopathy

MedlinePlus Genetics provides information about Idiopathic inflammatory myopathy

More About This Health Condition

Intervertebral disc disease

MedlinePlus Genetics provides information about Intervertebral disc disease

More About This Health Condition


MedlinePlus Genetics provides information about Keratoconus

More About This Health Condition

Other disorders

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.

Other Names for This Gene

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

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • 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, Sarasua 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. doi: 10.1002/ajmg.a.20137. Citation on PubMed
  • Brown MA, Xu H, Li Z. Genetics and the axial spondyloarthritis spectrum. Rheumatology (Oxford). 2020 Oct 1;59(Suppl4):iv58-iv66. doi: 10.1093/rheumatology/keaa464. Citation on PubMed
  • 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. doi: 10.1902/jop.2003.74.3.391. Citation on PubMed
  • 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. doi: 10.1007/s00251-007-0213-y. Epub 2007 Apr 18. Citation on PubMed
  • 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. Citation on PubMed
  • 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. doi: 10.1136/ard.2007.081364. Epub 2007 Dec 6. Citation on PubMed
  • 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. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.