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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.

Read more about gene names and symbols on the About page.

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) (NCBIThis link leads to a site outside Genetics Home Reference.)

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

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 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.

See also Understanding Medical Terminology.

References (15 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.

Reviewed: September 2009
Published: February 8, 2016