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Genetics Home Reference: your guide to understanding genetic conditions
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SAA1

Reviewed September 2008

What is the official name of the SAA1 gene?

The official name of this gene is “serum amyloid A1.”

SAA1 is the gene's official symbol. The SAA1 gene is also known by other names, listed below.

What is the normal function of the SAA1 gene?

The SAA1 gene provides instructions for making a protein called serum amyloid A1. This protein is made primarily in the liver and circulates in low levels in the blood. Although its function is not fully understood, serum amyloid A1 appears to play a role in the immune system. Serum amyloid A1 may help repair damaged tissues, act as an antibacterial agent, and signal the migration of germ-fighting cells to sites of infection.

Levels of this protein increase in the blood and other tissues under conditions of inflammation. Inflammation occurs when the immune system sends signaling molecules and white blood cells to a site of injury or disease to fight microbial invaders and facilitate tissue repair. When this has been accomplished, the body stops the inflammatory response to prevent damage to its own cells and tissues.

There are three versions of the serum amyloid A1 protein, known as alpha, beta, and gamma, which differ by one or two protein building blocks (amino acids). The frequency of these variants differs across populations. In Caucasian populations, the alpha version predominates and gamma is rare. In the Japanese population, however, the three versions appear almost equally.

Does the SAA1 gene share characteristics with other genes?

The SAA1 gene belongs to a family of genes called endogenous ligands (endogenous ligands).

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? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.

How are changes in the SAA1 gene related to health conditions?

familial Mediterranean fever - course of condition modified by normal variations in the SAA1 gene

Several studies of people with familial Mediterranean fever indicate that having the alpha version of the serum amyloid A1 protein increases the risk of a serious complication called amyloidosis. Amyloidosis involves the buildup of protein deposits that can lead to kidney failure if left untreated. Studies indicate that individuals with familial Mediterranean fever who also have the alpha version of the protein are two to seven times more likely to develop amyloidosis than are people with the beta or gamma version.

More serum amyloid A1 is produced in the body during episodes of inflammation such as those that occur in familial Mediterranean fever. This protein and related compounds may form abnormal clumps in the body's organs and tissues. It remains unclear, however, how the alpha version of serum amyloid A1 increases the susceptibility to amyloidosis (or alternatively, how the beta and gamma versions may protect against this complication) in people with this disorder.

other disorders - course of condition modified by normal variations in the SAA1 gene

Among people with certain other inflammatory disorders, studies indicate that variants of the serum amyloid A1 protein also modify the risk of amyloidosis. For example, in the Japanese population, the gamma version of the protein appears to increase the risk of amyloidosis among adults with rheumatoid arthritis. Among Caucasians with juvenile chronic arthritis, the alpha version indicates a high risk of developing amyloidosis.

More serum amyloid A1 is produced in the body during chronic inflammation such as occurs in these disorders. This protein and related compounds may form abnormal clumps in the body's organs and tissues. It remains unclear, however, how certain versions of serum amyloid A1 increase the susceptibility to amyloidosis.

Where is the SAA1 gene located?

Cytogenetic Location: 11p15.1

Molecular Location on chromosome 11: base pairs 18,266,260 to 18,269,976

The SAA1 gene is located on the short (p) arm of chromosome 11 at position 15.1.

The SAA1 gene is located on the short (p) arm of chromosome 11 at position 15.1.

More precisely, the SAA1 gene is located from base pair 18,266,260 to base pair 18,269,976 on chromosome 11.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about SAA1?

You and your healthcare professional may find the following resources about SAA1 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 SAA1 gene or gene products?

  • PIG4
  • SAA
  • SAA_HUMAN
  • TP53I4
  • tumor protein p53 inducible protein 4

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding SAA1?

acids ; amyloid ; amyloidosis ; antibacterial ; arthritis ; chronic ; complication ; familial ; fever ; gene ; immune system ; infection ; inflammation ; injury ; juvenile ; kidney ; population ; protein ; susceptibility ; tissue ; tumor ; white blood cells

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).

References

  • Bakkaloglu A, Duzova A, Ozen S, Balci B, Besbas N, Topaloglu R, Ozaltin F, Yilmaz E. Influence of Serum Amyloid A (SAA1) and SAA2 gene polymorphisms on renal amyloidosis, and on SAA/C-reactive protein values in patients with familial mediterranean fever in the Turkish population. J Rheumatol. 2004 Jun;31(6):1139-42. (http://www.ncbi.nlm.nih.gov/pubmed/15170927?dopt=Abstract)
  • Ben-Chetrit E. Familial Mediterranean fever (FMF) and renal AA amyloidosis--phenotype-genotype correlation, treatment and prognosis. J Nephrol. 2003 May-Jun;16(3):431-4. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12832747?dopt=Abstract)
  • Booth DR, Booth SE, Gillmore JD, Hawkins PN, Pepys MB. SAA1 alleles as risk factors in reactive systemic AA amyloidosis. Amyloid. 1998 Dec;5(4):262-5. (http://www.ncbi.nlm.nih.gov/pubmed/10036584?dopt=Abstract)
  • Cazeneuve C, Ajrapetyan H, Papin S, Roudot-Thoraval F, Geneviève D, Mndjoyan E, Papazian M, Sarkisian A, Babloyan A, Boissier B, Duquesnoy P, Kouyoumdjian JC, Girodon-Boulandet E, Grateau G, Sarkisian T, Amselem S. Identification of MEFV-independent modifying genetic factors for familial Mediterranean fever. Am J Hum Genet. 2000 Nov;67(5):1136-43. Epub 2000 Oct 3. (http://www.ncbi.nlm.nih.gov/pubmed/11017802?dopt=Abstract)
  • Delibaş A, Oner A, Balci B, Demircin G, Bulbul M, Bek K, Erdoğan O, Baysun S, Yilmaz E. Genetic risk factors of amyloidogenesis in familial Mediterranean fever. Am J Nephrol. 2005 Sep-Oct;25(5):434-40. Epub 2005 Aug 23. (http://www.ncbi.nlm.nih.gov/pubmed/16118480?dopt=Abstract)
  • Gershoni-Baruch R, Brik R, Zacks N, Shinawi M, Lidar M, Livneh A. The contribution of genotypes at the MEFV and SAA1 loci to amyloidosis and disease severity in patients with familial Mediterranean fever. Arthritis Rheum. 2003 Apr;48(4):1149-55. (http://www.ncbi.nlm.nih.gov/pubmed/12687559?dopt=Abstract)
  • Kelkitli E, Bilgici B, Tokgöz B, Dilek M, Bedir A, Akpolat I, Utas C, Akpolat T. SAA1 alpha/alpha alleles in amyloidosis. J Nephrol. 2006 Mar-Apr;19(2):189-91. (http://www.ncbi.nlm.nih.gov/pubmed/16736418?dopt=Abstract)
  • Medlej-Hashim M, Delague V, Chouery E, Salem N, Rawashdeh M, Lefranc G, Loiselet J, Mégarbané A. Amyloidosis in familial Mediterranean fever patients: correlation with MEFV genotype and SAA1 and MICA polymorphisms effects. BMC Med Genet. 2004 Feb 10;5:4. (http://www.ncbi.nlm.nih.gov/pubmed/15018633?dopt=Abstract)
  • Moriguchi M, Kaneko H, Terai C, Koseki Y, Kajiyama H, Inada S, Kitamura Y, Kamatani N. Relative transcriptional activities of SAA1 promoters polymorphic at position -13(T/C): potential association between increased transcription and amyloidosis. Amyloid. 2005 Mar;12(1):26-32. (http://www.ncbi.nlm.nih.gov/pubmed/16076608?dopt=Abstract)
  • Moriguchi M, Terai C, Koseki Y, Uesato M, Nakajima A, Inada S, Nishinarita M, Uchida S, Nakajima A, Kim SY, Chen CL, Kamatani N. Influence of genotypes at SAA1 and SAA2 loci on the development and the length of latent period of secondary AA-amyloidosis in patients with rheumatoid arthritis. Hum Genet. 1999 Oct;105(4):360-6. (http://www.ncbi.nlm.nih.gov/pubmed/10543406?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/6288)
  • Ray A, Shakya A, Kumar D, Benson MD, Ray BK. Inflammation-responsive transcription factor SAF-1 activity is linked to the development of amyloid A amyloidosis. J Immunol. 2006 Aug 15;177(4):2601-9. (http://www.ncbi.nlm.nih.gov/pubmed/16888022?dopt=Abstract)
  • OMIM: SERUM AMYLOID A1 (http://omim.org/entry/104750)
  • Stevens FJ. Hypothetical structure of human serum amyloid A protein. Amyloid. 2004 Jun;11(2):71-80. (http://www.ncbi.nlm.nih.gov/pubmed/15478462?dopt=Abstract)
  • Thorn CF, Lu ZY, Whitehead AS. Tissue-specific regulation of the human acute-phase serum amyloid A genes, SAA1 and SAA2, by glucocorticoids in hepatic and epithelial cells. Eur J Immunol. 2003 Sep;33(9):2630-9. (http://www.ncbi.nlm.nih.gov/pubmed/12938239?dopt=Abstract)
  • Utku U, Dilek M, Akpolat I, Bedir A, Akpolat T. SAA1 alpha/alpha alleles in Behçet's disease related amyloidosis. Clin Rheumatol. 2007 Jun;26(6):927-9. Epub 2006 Oct 13. (http://www.ncbi.nlm.nih.gov/pubmed/17039260?dopt=Abstract)
  • Yamada T. Serum amyloid A (SAA): a concise review of biology, assay methods and clinical usefulness. Clin Chem Lab Med. 1999 Apr;37(4):381-8. Review. (http://www.ncbi.nlm.nih.gov/pubmed/10369107?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: September 2008
Published: November 17, 2014