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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed September 2009

What is the official name of the SEPT9 gene?

The official name of this gene is “septin 9.”

SEPT9 is the gene's official symbol. The SEPT9 gene is also known by other names, listed below.

What is the normal function of the SEPT9 gene?

The SEPT9 gene provides instructions for making a protein called septin-9, which is part of a group of proteins called septins. Septins are involved in a process called cytokinesis, which is the step in cell division when the fluid inside the cell (cytoplasm) divides to form two separate cells. The septin-9 protein also seems to act as a tumor suppressor, which means that it regulates cell growth and keeps cells from dividing too fast or in an uncontrolled way.

The SEPT9 gene seems to be turned on (active) in cells throughout the body. Approximately 15 slightly different versions (isoforms) of the septin-9 protein may be produced from this gene. Some types of cells make certain isoforms, while other cell types produce other isoforms. However, the specific distribution of these isoforms in the body's tissues is not well understood. Septin-9 isoforms interact with other septin proteins to perform some of their functions.

How are changes in the SEPT9 gene related to health conditions?

hereditary neuralgic amyotrophy - caused by mutations in the SEPT9 gene

A few SEPT9 gene mutations have been identified in individuals with hereditary neuralgic amyotrophy, a disorder characterized by episodes of severe pain and muscle wasting (amyotrophy) in the shoulders and arms. The most common mutation results in the replacement of the protein building block (amino acid) arginine with the amino acid tryptophan at position 88 in the septin-9 protein sequence, written as Arg88Trp or R88W. This mutation has appeared in several unrelated families from different parts of the world. Duplication of genetic material within the SEPT9 gene has also been identified in affected individuals.

Changes in the SEPT9 gene may alter the sequence of amino acids in certain septin-9 isoforms in ways that interfere with their function. These mutations may also change the distribution of septin-9 isoforms and their interactions with other septin proteins in some of the body's tissues. This change in the functioning of septin proteins seems to particularly affect the network of nerves controlling movement and sensation in the shoulders and arms (brachial plexus), but the reason for this is unknown.

Because many of the triggers for episodes of hereditary neuralgic amyotrophy also affect the immune system, researchers believe that an autoimmune reaction may be involved in this disorder. However, the relation between SEPT9 gene mutations and immune function is unclear. Autoimmune disorders occur when the immune system malfunctions and attacks the body's own tissues and organs. An autoimmune attack on the nerves in the brachial plexus likely results in the signs and symptoms of hereditary neuralgic amyotrophy.

cancers - associated with the SEPT9 gene

Alterations in the activity (expression) of the SEPT9 gene are associated with certain cancers. The altered gene expression may enhance several cancer-related events such as cell division (proliferation), cell movement, and the development of new blood vessels (angiogenesis) that nourish a growing tumor. Increased production of particular isoforms of the septin-9 protein has been associated with breast and prostate cancers. Altered SEPT9 gene expression has also been found in many other cancers, including tumors of the ovary, pancreas, lung, kidney, liver, thyroid and esophagus.

Where is the SEPT9 gene located?

Cytogenetic Location: 17q25

Molecular Location on chromosome 17: base pairs 77,281,410 to 77,500,596

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

The SEPT9 gene is located on the long (q) arm of chromosome 17 at position 25.

The SEPT9 gene is located on the long (q) arm of chromosome 17 at position 25.

More precisely, the SEPT9 gene is located from base pair 77,281,410 to base pair 77,500,596 on chromosome 17.

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

Where can I find additional information about SEPT9?

You and your healthcare professional may find the following resources about SEPT9 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 SEPT9 gene or gene products?

  • AF17q25
  • FLJ75490
  • KIAA0991
  • MLL septin-like fusion
  • MSF
  • MSF1
  • NAPB
  • ovarian/breast septin
  • Ov/Br septin
  • PNUTL4
  • SeptD1
  • septin 9 isoform a
  • septin 9 isoform b
  • septin 9 isoform c
  • septin 9 isoform d
  • septin 9 isoform e
  • septin 9 isoform f
  • septin D1
  • SINT1

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

What glossary definitions help with understanding SEPT9?

acids ; amino acid ; angiogenesis ; arginine ; autoimmune ; cancer ; cell ; cell division ; cytokinesis ; cytoplasm ; duplication ; esophagus ; gene ; gene expression ; hereditary ; immune system ; isoforms ; kidney ; mutation ; ovarian ; ovary ; pancreas ; proliferation ; prostate ; protein ; protein sequence ; thyroid ; tryptophan ; tumor ; wasting

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


  • Gene Review: Hereditary Neuralgic Amyotrophy (
  • Gonzalez ME, Makarova O, Peterson EA, Privette LM, Petty EM. Up-regulation of SEPT9_v1 stabilizes c-Jun-N-terminal kinase and contributes to its pro-proliferative activity in mammary epithelial cells. Cell Signal. 2009 Apr;21(4):477-87. doi: 10.1016/j.cellsig.2008.11.007. Epub 2008 Nov 18. (
  • Gonzalez ME, Peterson EA, Privette LM, Loffreda-Wren JL, Kalikin LM, Petty EM. High SEPT9_v1 expression in human breast cancer cells is associated with oncogenic phenotypes. Cancer Res. 2007 Sep 15;67(18):8554-64. (
  • Hannibal MC, Ruzzo EK, Miller LR, Betz B, Buchan JG, Knutzen DM, Barnett K, Landsverk ML, Brice A, LeGuern E, Bedford HM, Worrall BB, Lovitt S, Appel SH, Andermann E, Bird TD, Chance PF. SEPT9 gene sequencing analysis reveals recurrent mutations in hereditary neuralgic amyotrophy. Neurology. 2009 May 19;72(20):1755-9. doi: 10.1212/WNL.0b013e3181a609e3. (
  • Hoque R, Schwendimann RN, Kelley RE, Bien-Willner R, Sivakumar K. Painful brachial plexopathies in SEPT9 mutations: adverse outcome related to comorbid states. J Clin Neuromuscul Dis. 2008 Jun;9(4):379-84. doi: 10.1097/CND.0b013e318166ee89. (
  • Klein CJ, Wu Y, Cunningham JM, Windebank AJ, Dyck PJ, Friedenberg SM, Klein DM, Dyck PJ. SEPT9 mutations and a conserved 17q25 sequence in sporadic and hereditary brachial plexus neuropathy. Arch Neurol. 2009 Feb;66(2):238-43. doi: 10.1001/archneurol.2008.585. (
  • Kuhlenbäumer G, Hannibal MC, Nelis E, Schirmacher A, Verpoorten N, Meuleman J, Watts GD, De Vriendt E, Young P, Stögbauer F, Halfter H, Irobi J, Goossens D, Del-Favero J, Betz BG, Hor H, Kurlemann G, Bird TD, Airaksinen E, Mononen T, Serradell AP, Prats JM, Van Broeckhoven C, De Jonghe P, Timmerman V, Ringelstein EB, Chance PF. Mutations in SEPT9 cause hereditary neuralgic amyotrophy. Nat Genet. 2005 Oct;37(10):1044-6. Epub 2005 Sep 25. (
  • Laccone F, Hannibal MC, Neesen J, Grisold W, Chance PF, Rehder H. Dysmorphic syndrome of hereditary neuralgic amyotrophy associated with a SEPT9 gene mutation--a family study. Clin Genet. 2008 Sep;74(3):279-83. doi: 10.1111/j.1399-0004.2008.01022.x. Epub 2008 May 19. (
  • Landsverk ML, Ruzzo EK, Mefford HC, Buysse K, Buchan JG, Eichler EE, Petty EM, Peterson EA, Knutzen DM, Barnett K, Farlow MR, Caress J, Parry GJ, Quan D, Gardner KL, Hong M, Simmons Z, Bird TD, Chance PF, Hannibal MC. Duplication within the SEPT9 gene associated with a founder effect in North American families with hereditary neuralgic amyotrophy. Hum Mol Genet. 2009 Apr 1;18(7):1200-8. doi: 10.1093/hmg/ddp014. Epub 2009 Jan 12. (
  • McDade SS, Hall PA, Russell SE. Translational control of SEPT9 isoforms is perturbed in disease. Hum Mol Genet. 2007 Apr 1;16(7):742-52. (
  • NCBI Gene (
  • Scott M, Hyland PL, McGregor G, Hillan KJ, Russell SE, Hall PA. Multimodality expression profiling shows SEPT9 to be overexpressed in a wide range of human tumours. Oncogene. 2005 Jul 7;24(29):4688-700. (
  • Scott M, McCluggage WG, Hillan KJ, Hall PA, Russell SE. Altered patterns of transcription of the septin gene, SEPT9, in ovarian tumorigenesis. Int J Cancer. 2006 Mar 1;118(5):1325-9. (
  • OMIM: SEPTIN 9 (
  • Sudo K, Ito H, Iwamoto I, Morishita R, Asano T, Nagata K. SEPT9 sequence alternations causing hereditary neuralgic amyotrophy are associated with altered interactions with SEPT4/SEPT11 and resistance to Rho/Rhotekin-signaling. Hum Mutat. 2007 Oct;28(10):1005-13. (


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: September 2009
Published: February 1, 2016