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


Reviewed November 2006

What is the official name of the TRIOBP gene?

The official name of this gene is “TRIO and F-actin binding protein.”

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

What is the normal function of the TRIOBP gene?

The TRIOBP gene provides instructions for making a protein called TRIO and F-actin binding protein (Triobp). Within cells, the Triobp protein likely regulates aspects of the cytoskeleton, the structural framework that helps to determine cell shape, size, and movement. The Triobp protein is thought to help control the organization of actin filaments, which are long, thin fibers that make up a significant part of the cytoskeleton . Actin filaments are necessary for several normal cellular functions, such as cell division, cell movement (motility), maintenance of cell shape, transport of proteins and other molecules within cells, and chemical signaling between cells.

There are two versions of Triobp, a short version found in most body tissues, and a long version made only in the brain, the eye, and the inner ear. Because of its presence in the inner ear, especially the snail-shaped structure called the cochlea, researchers are interested in this protein's role in hearing. Triobp probably plays a role in the development and maintenance of stereocilia, which are hairlike projections that line the inner ear. Stereocilia, which are rich in actin, bend in response to sound waves. This bending motion is essential for converting sound waves to nerve impulses, a critical process for normal hearing.

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

nonsyndromic deafness - caused by mutations in the TRIOBP gene

Researchers have identified at least nine TRIOBP mutations that cause a form of nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body) called DFNB28. Almost all of these mutations introduce a premature stop signal in the instructions for making the long version of Triobp. As a result, an abnormally small version of this protein is made in the brain and inner ear. The abnormal protein probably cannot interact with the actin filaments within stereocilia, leading to hearing loss.

Where is the TRIOBP gene located?

Cytogenetic Location: 22q13.1

Molecular Location on chromosome 22: base pairs 37,696,988 to 37,776,556

The TRIOBP gene is located on the long (q) arm of chromosome 22 at position 13.1.

The TRIOBP gene is located on the long (q) arm of chromosome 22 at position 13.1.

More precisely, the TRIOBP gene is located from base pair 37,696,988 to base pair 37,776,556 on chromosome 22.

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

Where can I find additional information about TRIOBP?

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

  • DFNB28
  • dJ37E16.4
  • FLJ39315
  • HRIHFB2122
  • KIAA1662
  • OTTHUMP00000028958
  • TAP68
  • TARA
  • tara-like protein
  • trio-associated repeat on actin

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

What glossary definitions help with understanding TRIOBP?

actin ; autosomal ; autosomal recessive ; cell ; cell division ; cochlea ; cytoskeleton ; gene ; protein ; recessive

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


  • NCBI Gene (
  • Riazuddin S, Khan SN, Ahmed ZM, Ghosh M, Caution K, Nazli S, Kabra M, Zafar AU, Chen K, Naz S, Antonellis A, Pavan WJ, Green ED, Wilcox ER, Friedman PL, Morell RJ, Riazuddin S, Friedman TB. Mutations in TRIOBP, which encodes a putative cytoskeletal-organizing protein, are associated with nonsyndromic recessive deafness. Am J Hum Genet. 2006 Jan;78(1):137-43. Epub 2005 Nov 21. (
  • Seipel K, O'Brien SP, Iannotti E, Medley QG, Streuli M. Tara, a novel F-actin binding protein, associates with the Trio guanine nucleotide exchange factor and regulates actin cytoskeletal organization. J Cell Sci. 2001 Jan;114(Pt 2):389-99. (
  • Shahin H, Walsh T, Sobe T, Abu Sa'ed J, Abu Rayan A, Lynch ED, Lee MK, Avraham KB, King MC, Kanaan M. Mutations in a novel isoform of TRIOBP that encodes a filamentous-actin binding protein are responsible for DFNB28 recessive nonsyndromic hearing loss. Am J Hum Genet. 2006 Jan;78(1):144-52. Epub 2005 Nov 21. (


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: November 2006
Published: November 23, 2015