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TCOF1 gene

treacle ribosome biogenesis factor 1

Normal Function

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.

Health Conditions Related to Genetic Changes

Treacher Collins syndrome

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.

More About This Health Condition


MedlinePlus Genetics provides information about Coloboma

More About This Health Condition

Other Names for This Gene

  • TCS
  • Treacher Collins syndrome protein
  • Treacher Collins-Franceschetti syndrome 1
  • treacle

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


  • Barbosa M, Jabs EW, Huston S. Treacher Collins Syndrome. 2004 Jul 20 [updated 2024 Jun 20]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from Citation on PubMed
  • 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. Citation on PubMed or Free article on PubMed Central
  • 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. doi: 10.1073/pnas.0603730103. Epub 2006 Aug 28. Citation on PubMed or Free article on PubMed Central
  • 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. doi: 10.1093/hmg/ddi208. Epub 2005 Jun 1. Citation on PubMed
  • 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. doi: 10.1002/ajmg.a.30357. Citation on PubMed
  • Marszalek B, Wojcicki P, Kobus K, Trzeciak WH. Clinical features, treatment and genetic background of Treacher Collins syndrome. J Appl Genet. 2002;43(2):223-33. Citation on PubMed
  • 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. Citation on PubMed or Free article on PubMed Central
  • 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. doi: 10.1002/humu.20159. Citation on PubMed
  • 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. doi: 10.1002/1098-1004(200010)16:43.0.CO;2-H. Citation on PubMed
  • 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. doi: 10.1073/pnas.0402492101. Epub 2004 Jul 12. Citation on PubMed or Free article on PubMed Central

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