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


Reviewed December 2009

What is the official name of the TBX5 gene?

The official name of this gene is “T-box 5.”

TBX5 is the gene's official symbol. The TBX5 gene is also known by other names, listed below.

What is the normal function of the TBX5 gene?

The TBX5 gene provides instructions for making a protein called T-box 5 that plays an important role in the formation of tissues and organs during embryonic development. This protein regulates the activity of other genes by attaching (binding) to specific regions of DNA. On the basis of this action, the T-box 5 protein is called a transcription factor.

During embryonic development, the T-box 5 protein turns on (activates) genes involved in the normal development of the hands and arms (upper limbs). The T-box 5 protein also activates genes that play an important role in the growth and development of the heart. This protein appears to be particularly important for the formation of the wall (septum) that separates the right and left sides of the heart. The T-box 5 protein is also critical to the formation of the electrical system that coordinates contractions of the heart chambers.

Does the TBX5 gene share characteristics with other genes?

The TBX5 gene belongs to a family of genes called TBX (T-boxes).

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? ( in the Handbook.

How are changes in the TBX5 gene related to health conditions?

Holt-Oram syndrome - caused by mutations in the TBX5 gene

More than 70 mutations in the TBX5 gene have been found to cause Holt-Oram syndrome. Most of these mutations prevent the production of the T-box 5 protein. Other mutations change one of the protein building blocks (amino acids) used to make the T-box 5 protein. Researchers believe that a change in amino acids impairs the protein's ability to bind to DNA. As a result of TBX5 mutations, genes that are important for development of the heart and upper limbs are probably not activated. Abnormal development of the heart and upper limbs is characteristic of Holt-Oram syndrome.

Where is the TBX5 gene located?

Cytogenetic Location: 12q24.1

Molecular Location on chromosome 12: base pairs 114,353,930 to 114,408,442

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

The TBX5 gene is located on the long (q) arm of chromosome 12 at position 24.1.

The TBX5 gene is located on the long (q) arm of chromosome 12 at position 24.1.

More precisely, the TBX5 gene is located from base pair 114,353,930 to base pair 114,408,442 on chromosome 12.

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

Where can I find additional information about TBX5?

You and your healthcare professional may find the following resources about TBX5 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 TBX5 gene or gene products?

  • HOS
  • T-box transcription factor TBX5

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

What glossary definitions help with understanding TBX5?

acids ; DNA ; embryonic ; gene ; protein ; septum ; syndrome ; transcription ; transcription factor

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


  • Cerbai E, Sartiani L. Holt-oram syndrome and atrial fibrillation: opening the (T)-box. Circ Res. 2008 Jun 6;102(11):1304-6. doi: 10.1161/CIRCRESAHA.108.178079. (
  • Debeer P, Race V, Gewillig M, Devriendt K, Frijns JP. Novel TBX5 mutations in patients with Holt-Oram syndrome. Clin Orthop Relat Res. 2007 Sep;462:20-6. (
  • Hatcher CJ, McDermott DA. Using the TBX5 transcription factor to grow and sculpt the heart. Am J Med Genet A. 2006 Jul 1;140(13):1414-8. Review. (
  • McDermott DA, Bressan MC, He J, Lee JS, Aftimos S, Brueckner M, Gilbert F, Graham GE, Hannibal MC, Innis JW, Pierpont ME, Raas-Rothschild A, Shanske AL, Smith WE, Spencer RH, St John-Sutton MG, van Maldergem L, Waggoner DJ, Weber M, Basson CT. TBX5 genetic testing validates strict clinical criteria for Holt-Oram syndrome. Pediatr Res. 2005 Nov;58(5):981-6. Epub 2005 Sep 23. (
  • Mori AD, Bruneau BG. TBX5 mutations and congenital heart disease: Holt-Oram syndrome revealed. Curr Opin Cardiol. 2004 May;19(3):211-5. Review. (
  • NCBI Gene (
  • Stennard FA, Harvey RP. T-box transcription factors and their roles in regulatory hierarchies in the developing heart. Development. 2005 Nov;132(22):4897-910. Review. (
  • OMIM: T-BOX 5 (


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: December 2009
Published: February 8, 2016