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TBP gene

TATA-box binding protein

Normal Function

The TBP gene provides instructions for making a protein called the TATA box binding protein. This protein is active in cells and tissues throughout the body, where it plays an essential role in regulating the activity of most genes.

The TATA box binding protein attaches (binds) to a particular sequence of DNA known as the TATA box. This sequence occurs in a regulatory region of DNA near the beginning of many genes. Once the protein is attached to the TATA box near a gene, it acts as a landmark to indicate where other enzymes should start reading the gene. The process of reading a gene's DNA and transferring the information to a similar molecule called mRNA is known as transcription.

One region of the TBP gene contains a particular DNA segment known as a CAG/CAA trinucleotide repeat. This segment is made up of a series of three DNA building blocks (nucleotides) that appear multiple times in a row. Normally, the CAG/CAA segment is repeated 25 to 42 times within the gene.

Health Conditions Related to Genetic Changes

Huntington's disease-like syndrome

A particular type of variant (also called a mutation) in the TBP gene has been found to cause a progressive brain disorder known as Huntington's disease-like 4 (HDL4) or spinocerebellar ataxia type 17 (SCA17). The features of this disorder vary widely among affected individuals. The condition was first described as HDL4 in people whose signs and symptoms closely resembled those of Huntington's disease, including uncontrolled movements, emotional problems, and loss of thinking ability. The disorder is now more commonly known as SCA17 because difficulty coordinating movements (ataxia) and other movement problems are the most frequent signs and symptoms. It is unknown why some people with TBP gene variants have a disorder resembling Huntington's disease, while others have more prominent ataxia.

The variants associated with HDL4/SCA17 increases the size of the CAG/CAA trinucleotide repeat in the TBP gene. People with this condition have 43 to 66 CAG/CAA repeats. People with 43 to 48 CAG/CAA repeats may or may not have signs and symptoms, while people with 49 or more repeats almost always develop the disorder.

An increased number of CAG/CAA repeats in the TBP gene leads to the production of an abnormally long version of the TATA box binding protein. The abnormal protein builds up in nerve cells (neurons) in the brain and disrupts the normal functions of these cells. The dysfunction and eventual death of neurons in certain areas of the brain underlie the signs and symptoms of HDL4/SCA17. Because the TBP gene is active throughout the body, it is unclear why the effects of a variant in this gene are limited to the brain.

More About This Health Condition

Other Names for This Gene

  • CCG1 Protein
  • CCGS
  • Cell Cycle Gene 1 Protein
  • DYT3 protein, human
  • GTF2D
  • GTF2D1
  • RNA Polymerase II TATA-Binding Protein
  • RNA Polymerase IIA 250kD
  • SCA17
  • TAF(II)250
  • TAF1 RNA Polymerase II TATA Box Binding Protein
  • TAF2A
  • TAFII250
  • TATA box binding protein
  • TATA Sequence-Binding Protein
  • TATA-Binding Protein
  • TATA-Box Factor
  • TF2D
  • Transcription Factor IID
  • Transcription Factor TBP
  • Transcription Initiation Factor TFIID 250 kDa Subunit

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


  • Bauer P, Laccone F, Rolfs A, Wullner U, Bosch S, Peters H, Liebscher S, Scheible M, Epplen JT, Weber BH, Holinski-Feder E, Weirich-Schwaiger H, Morris-Rosendahl DJ, Andrich J, Riess O. Trinucleotide repeat expansion in SCA17/TBP in white patients with Huntington's disease-like phenotype. J Med Genet. 2004 Mar;41(3):230-2. doi: 10.1136/jmg.2003.015602. No abstract available. Citation on PubMed or Free article on PubMed Central
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  • Schneider SA, van de Warrenburg BP, Hughes TD, Davis M, Sweeney M, Wood N, Quinn NP, Bhatia KP. Phenotypic homogeneity of the Huntington disease-like presentation in a SCA17 family. Neurology. 2006 Nov 14;67(9):1701-3. doi: 10.1212/01.wnl.0000242740.01273.00. Citation on PubMed
  • van Roon-Mom WM, Reid SJ, Faull RL, Snell RG. TATA-binding protein in neurodegenerative disease. Neuroscience. 2005;133(4):863-72. doi: 10.1016/j.neuroscience.2005.03.024. Citation on PubMed
  • Zuhlke C, Hellenbroich Y, Dalski A, Kononowa N, Hagenah J, Vieregge P, Riess O, Klein C, Schwinger E. Different types of repeat expansion in the TATA-binding protein gene are associated with a new form of inherited ataxia. Eur J Hum Genet. 2001 Mar;9(3):160-4. doi: 10.1038/sj.ejhg.5200617. 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.