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TBX5 gene

T-box transcription factor 5

Normal Function

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.

Health Conditions Related to Genetic Changes

Holt-Oram syndrome

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.

More About This Health Condition

Other Names for This Gene

  • HOS
  • T-box transcription factor TBX5

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • 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. No abstract available. Citation on PubMed
  • 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. doi: 10.1097/BLO.0b013e3181123ffe. Citation on PubMed
  • 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. doi: 10.1002/ajmg.a.31256. Citation on PubMed
  • 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. doi: 10.1203/01.PDR.0000182593.95441.64. Epub 2005 Sep 23. Citation on PubMed
  • Mori AD, Bruneau BG. TBX5 mutations and congenital heart disease: Holt-Oram syndrome revealed. Curr Opin Cardiol. 2004 May;19(3):211-5. doi: 10.1097/00001573-200405000-00004. Citation on PubMed
  • 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. doi: 10.1242/dev.02099. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.