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


Reviewed June 2012

What is the official name of the TCOF1 gene?

The official name of this gene is “Treacher Collins-Franceschetti syndrome 1.”

TCOF1 is the gene's official symbol. The TCOF1 gene is also known by other names, listed below.

What is the normal function of the TCOF1 gene?

The TCOF1 gene provides instructions for making a protein called treacle. This protein is active during early embryonic development in structures that become bones and other tissues of the face, and it appears to play a critical role in the formation of these structures.

Studies suggest that treacle is involved in the production of a molecule called ribosomal RNA (rRNA), a chemical cousin of DNA. Ribosomal RNA helps assemble protein building blocks (amino acids) into functioning proteins, which is essential for the normal functioning and survival of cells. Treacle is active in the nucleolus, which is a small region inside the nucleus where rRNA is produced.

How are changes in the TCOF1 gene related to health conditions?

Treacher Collins syndrome - caused by mutations in the TCOF1 gene

About 200 mutations in the TCOF1 gene have been identified in people with Treacher Collins syndrome, a condition that affects the development of bones and other tissues of the face. Most of these mutations insert or delete a small number of DNA building blocks (base pairs) in the TCOF1 gene, which leads to a reduction in the amount of functional treacle in cells. As a result, the production of rRNA is reduced, which likely triggers the self-destruction (apoptosis) of certain cells involved in the early development of facial bones and tissues. Researchers believe that this abnormal cell death may lead to the specific problems with facial development found in Treacher Collins syndrome. However, it is unclear why the effects of a reduction in rRNA are limited to facial development.

Where is the TCOF1 gene located?

Cytogenetic Location: 5q32

Molecular Location on chromosome 5: base pairs 150,357,639 to 150,400,308

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

The TCOF1 gene is located on the long (q) arm of chromosome 5 at position 32.

The TCOF1 gene is located on the long (q) arm of chromosome 5 at position 32.

More precisely, the TCOF1 gene is located from base pair 150,357,639 to base pair 150,400,308 on chromosome 5.

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

Where can I find additional information about TCOF1?

You and your healthcare professional may find the following resources about TCOF1 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 TCOF1 gene or gene products?

  • TCS
  • Treacher Collins syndrome protein
  • treacle

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

What glossary definitions help with understanding TCOF1?

acids ; apoptosis ; cell ; DNA ; embryonic ; gene ; molecule ; nucleolus ; nucleus ; protein ; ribosomal RNA ; RNA ; syndrome

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


  • Conte C, D'Apice MR, Rinaldi F, Gambardella S, Sangiuolo F, Novelli G. Novel mutations of TCOF1 gene in European patients with Treacher Collins syndrome. BMC Med Genet. 2011 Sep 27;12:125. doi: 10.1186/1471-2350-12-125. (
  • Dixon J, Jones NC, Sandell LL, Jayasinghe SM, Crane J, Rey JP, Dixon MJ, Trainor PA. Tcof1/Treacle is required for neural crest cell formation and proliferation deficiencies that cause craniofacial abnormalities. Proc Natl Acad Sci U S A. 2006 Sep 5;103(36):13403-8. Epub 2006 Aug 28. (
  • Gene Review: Treacher Collins Syndrome (
  • Gonzales B, Henning D, So RB, Dixon J, Dixon MJ, Valdez BC. The Treacher Collins syndrome (TCOF1) gene product is involved in pre-rRNA methylation. Hum Mol Genet. 2005 Jul 15;14(14):2035-43. Epub 2005 Jun 1. (
  • Horiuchi K, Ariga T, Fujioka H, Kawashima K, Yamamoto Y, Igawa H, Sugihara T, Sakiyama Y. Mutational analysis of the TCOF1 gene in 11 Japanese patients with Treacher Collins Syndrome and mechanism of mutagenesis. Am J Med Genet A. 2005 May 1;134(4):363-7. (
  • Marszałek B, Wójcicki P, Kobus K, Trzeciak WH. Clinical features, treatment and genetic background of Treacher Collins syndrome. J Appl Genet. 2002;43(2):223-33. Review. (
  • NCBI Gene (
  • Sakai D, Trainor PA. Treacher Collins syndrome: unmasking the role of Tcof1/treacle. Int J Biochem Cell Biol. 2009 Jun;41(6):1229-32. doi: 10.1016/j.biocel.2008.10.026. Epub 2008 Nov 5. Review. (
  • Splendore A, Fanganiello RD, Masotti C, Morganti LS, Passos-Bueno MR. TCOF1 mutation database: novel mutation in the alternatively spliced exon 6A and update in mutation nomenclature. Hum Mutat. 2005 May;25(5):429-34. (
  • Splendore A, Silva EO, Alonso LG, Richieri-Costa A, Alonso N, Rosa A, Carakushanky G, Cavalcanti DP, Brunoni D, Passos-Bueno MR. High mutation detection rate in TCOF1 among Treacher Collins syndrome patients reveals clustering of mutations and 16 novel pathogenic changes. Hum Mutat. 2000 Oct;16(4):315-22. Review. (
  • Valdez BC, Henning D, So RB, Dixon J, Dixon MJ. The Treacher Collins syndrome (TCOF1) gene product is involved in ribosomal DNA gene transcription by interacting with upstream binding factor. Proc Natl Acad Sci U S A. 2004 Jul 20;101(29):10709-14. Epub 2004 Jul 12. (


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: June 2012
Published: February 8, 2016