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Normal Function
The TBX1 gene provides instructions for making a protein called T-box protein 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.
T-box protein 1 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 T-box protein 1 acts as a transcription factor, researchers have not determined which genes are regulated by this protein.
Health Conditions Related to Genetic Changes
22q11.2 deletion syndrome
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 protein 1 that is produced in cells, while other mutations alter the protein's function. These genetic changes likely affect the ability of T-box protein 1 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 protein 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.
More About This Health ConditionOther Names for This Gene
- CAFS
- CTHM
- DGCR
- DGS
- DORV
- TBX1_HUMAN
- TBX1C
- Testis-specific T-box protein
- TGA
- VCFS
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
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. doi: 10.1093/hmg/ddl084. Epub 2006 Apr 6. Citation on PubMed or Free article on PubMed Central
- Baldini A. DiGeorge syndrome: an update. Curr Opin Cardiol. 2004 May;19(3):201-4. doi: 10.1097/00001573-200405000-00002. Citation on PubMed
- Baldini A. DiGeorge's syndrome: a gene at last. Lancet. 2003 Oct 25;362(9393):1342-3. doi: 10.1016/S0140-6736(03)14671-5. No abstract available. Citation on PubMed
- Baldini A. Dissecting contiguous gene defects: TBX1. Curr Opin Genet Dev. 2005 Jun;15(3):279-84. doi: 10.1016/j.gde.2005.03.001. Citation on PubMed
- Packham EA, Brook JD. T-box genes in human disorders. Hum Mol Genet. 2003 Apr 1;12 Spec No 1:R37-44. doi: 10.1093/hmg/ddg077. Citation on PubMed
- 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. doi: 10.1073/pnas.0600206103. Epub 2006 May 9. Citation on PubMed or Free article on PubMed Central
- Plageman TF Jr, Yutzey KE. T-box genes and heart development: putting the "T" in heart. Dev Dyn. 2005 Jan;232(1):11-20. doi: 10.1002/dvdy.20201. Citation on PubMed
- 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. doi: 10.1093/hmg/ddi081. Epub 2005 Feb 9. Citation on PubMed
- 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. doi: 10.1007/s00439-006-0242-x. Epub 2006 Oct 7. Citation on PubMed or Free article on PubMed Central
- 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. doi: 10.1016/s0140-6736(03)14632-6. Citation on PubMed
- Yamagishi H, Srivastava D. Unraveling the genetic and developmental mysteries of 22q11 deletion syndrome. Trends Mol Med. 2003 Sep;9(9):383-9. doi: 10.1016/s1471-4914(03)00141-2. Citation on PubMed
- Zweier C, Sticht H, Aydin-Yaylagul 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. doi: 10.1086/511993. Epub 2007 Jan 18. Citation on PubMed or Free article on PubMed Central
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