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Genetics Home Reference: your guide to understanding genetic conditions
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TBX1

Reviewed September 2007

What is the official name of the TBX1 gene?

The official name of this gene is “T-box 1.”

TBX1 is the gene's official symbol. The TBX1 gene is also known by other names, listed below.

What is the normal function of the TBX1 gene?

The TBX1 gene provides instructions for making a protein called T-box 1. Genes in the T-box family play important roles in the formation of tissues and organs during embryonic development. To carry out these roles, proteins produced from these genes bind to specific areas of DNA. The proteins attach to critical regions near genes and help control the activity of those genes. T-box proteins are called transcription factors on the basis of this action.

The T-box 1 protein appears to be necessary for the normal development of muscles and bones of the face and neck, large arteries that carry blood out of the heart, structures in the ear, and glands such as the thymus and parathyroid. Although the T-box 1 protein acts as a transcription factor, researchers have not determined which genes are regulated by this protein.

Does the TBX1 gene share characteristics with other genes?

The TBX1 gene belongs to a family of genes called TBX (T-box gene family).

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? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.

How are changes in the TBX1 gene related to health conditions?

22q11.2 deletion syndrome - associated with the TBX1 gene

Most cases of 22q11.2 deletion syndrome are caused by a deletion of a small piece of chromosome 22. This region of the chromosome contains 30 to 40 genes, including the TBX1 gene. In a small number of affected individuals without a chromosome 22 deletion, mutations in the TBX1 gene are thought to be responsible for the characteristic signs and symptoms of the syndrome. The identified mutations include changes in single DNA building blocks (base pairs) in the TBX1 gene and deletions of a small amount of genetic material from the gene. Some of these mutations reduce the amount of T-box 1 protein that is produced in cells, while other mutations alter the protein's function. These genetic changes likely affect the ability of the T-box 1 protein to bind to DNA and regulate the activity of other genes.

Researchers believe that changes in the TBX1 gene, due to either a mutation in the gene or a deletion of part of chromosome 22, are responsible for many of the features of 22q11.2 deletion syndrome. Specifically, a reduction in the amount of T-box 1 or changes in the protein's normal function are associated with heart defects, an opening in the roof of the mouth (a cleft palate), distinctive facial features, hearing loss, and low calcium levels. Some studies suggest that a loss of the TBX1 gene may also be associated with behavioral problems in affected individuals.

Where is the TBX1 gene located?

Cytogenetic Location: 22q11.21

Molecular Location on chromosome 22: base pairs 19,756,702 to 19,783,592

The TBX1 gene is located on the long (q) arm of chromosome 22 at position 11.21.

The TBX1 gene is located on the long (q) arm of chromosome 22 at position 11.21.

More precisely, the TBX1 gene is located from base pair 19,756,702 to base pair 19,783,592 on chromosome 22.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about TBX1?

You and your healthcare professional may find the following resources about TBX1 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 TBX1 gene or gene products?

  • CAFS
  • CTHM
  • DGCR
  • DGS
  • DORV
  • TBX1C
  • TBX1_HUMAN
  • Testis-specific T-box protein
  • TGA
  • VCFS

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding TBX1?

arteries ; calcium ; chromosome ; cleft palate ; deletion ; DNA ; embryonic ; gene ; mutation ; palate ; parathyroid ; protein ; syndrome ; testis ; thymus ; transcription ; transcription factor

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Arnold JS, Braunstein EM, Ohyama T, Groves AK, Adams JC, Brown MC, Morrow BE. Tissue-specific roles of Tbx1 in the development of the outer, middle and inner ear, defective in 22q11DS patients. Hum Mol Genet. 2006 May 15;15(10):1629-39. Epub 2006 Apr 6. (http://www.ncbi.nlm.nih.gov/pubmed/16600992?dopt=Abstract)
  • Baldini A. DiGeorge's syndrome: a gene at last. Lancet. 2003 Oct 25;362(9393):1342-3. (http://www.ncbi.nlm.nih.gov/pubmed/14585631?dopt=Abstract)
  • Baldini A. DiGeorge syndrome: an update. Curr Opin Cardiol. 2004 May;19(3):201-4. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15096950?dopt=Abstract)
  • Baldini A. Dissecting contiguous gene defects: TBX1. Curr Opin Genet Dev. 2005 Jun;15(3):279-84. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15917203?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/6899)
  • Packham EA, Brook JD. T-box genes in human disorders. Hum Mol Genet. 2003 Apr 1;12 Spec No 1:R37-44. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12668595?dopt=Abstract)
  • Paylor R, Glaser B, Mupo A, Ataliotis P, Spencer C, Sobotka A, Sparks C, Choi CH, Oghalai J, Curran S, Murphy KC, Monks S, Williams N, O'Donovan MC, Owen MJ, Scambler PJ, Lindsay E. Tbx1 haploinsufficiency is linked to behavioral disorders in mice and humans: implications for 22q11 deletion syndrome. Proc Natl Acad Sci U S A. 2006 May 16;103(20):7729-34. Epub 2006 May 9. (http://www.ncbi.nlm.nih.gov/pubmed/16684884?dopt=Abstract)
  • Plageman TF Jr, Yutzey KE. T-box genes and heart development: putting the "T" in heart. Dev Dyn. 2005 Jan;232(1):11-20. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15580613?dopt=Abstract)
  • Stoller JZ, Epstein JA. Identification of a novel nuclear localization signal in Tbx1 that is deleted in DiGeorge syndrome patients harboring the 1223delC mutation. Hum Mol Genet. 2005 Apr 1;14(7):885-92. Epub 2005 Feb 9. (http://www.ncbi.nlm.nih.gov/pubmed/15703190?dopt=Abstract)
  • Weksberg R, Stachon AC, Squire JA, Moldovan L, Bayani J, Meyn S, Chow E, Bassett AS. Molecular characterization of deletion breakpoints in adults with 22q11 deletion syndrome. Hum Genet. 2007 Feb;120(6):837-45. Epub 2006 Oct 7. (http://www.ncbi.nlm.nih.gov/pubmed/17028864?dopt=Abstract)
  • Yagi H, Furutani Y, Hamada H, Sasaki T, Asakawa S, Minoshima S, Ichida F, Joo K, Kimura M, Imamura S, Kamatani N, Momma K, Takao A, Nakazawa M, Shimizu N, Matsuoka R. Role of TBX1 in human del22q11.2 syndrome. Lancet. 2003 Oct 25;362(9393):1366-73. (http://www.ncbi.nlm.nih.gov/pubmed/14585638?dopt=Abstract)
  • Yamagishi H, Srivastava D. Unraveling the genetic and developmental mysteries of 22q11 deletion syndrome. Trends Mol Med. 2003 Sep;9(9):383-9. Review. (http://www.ncbi.nlm.nih.gov/pubmed/13129704?dopt=Abstract)
  • Zweier C, Sticht H, Aydin-Yaylagül I, Campbell CE, Rauch A. Human TBX1 missense mutations cause gain of function resulting in the same phenotype as 22q11.2 deletions. Am J Hum Genet. 2007 Mar;80(3):510-7. Epub 2007 Jan 18. (http://www.ncbi.nlm.nih.gov/pubmed/17273972?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: September 2007
Published: July 7, 2014