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Normal Function
The BCOR gene provides instructions for making a protein known as the BCL6 corepressor. A corepressor is a protein that cannot attach (bind) to DNA by itself, but it interacts with other DNA-binding proteins to suppress the activity of certain genes. In this case, the BCL6 corepressor partners with the DNA-binding protein produced from the BCL6 gene.
The BCL6 corepressor appears to play a critical role in early development, including the formation of the eyes and several other tissues and organs. Scientists believe that the BCL6 corepressor may also be involved in specifying the left and right sides of the body in the developing embryo. Research also shows that this protein may regulate development by influencing the self-destruction of cells that are damaged or no longer needed (apoptosis).
Health Conditions Related to Genetic Changes
Oculofaciocardiodental syndrome
Variants (also called mutations) in the BCOR gene can cause oculofaciocardiodental (OFCD) syndrome. This condition affects the development of the eyes (oculo-), facial features (facio-), heart (cardio-), and teeth (dental). Some of these variants delete large amounts of genetic material from the BCOR gene, while other variants alter the gene's instructions such that no BCL6 corepressor protein can be produced. A loss of this protein disrupts the normal development of the eyes and several other organs and tissues before birth.
OFCD syndrome occurs exclusively in individuals with two X chromosomes (typical of females). OFCD syndrome has an X-linked dominant inheritance pattern, which means that one altered copy of the BCOR gene in each cell is sufficient to cause the condition. The genetic changes that underlie OFCD syndrome prevent the production of any BCL6 corepressor protein. As a result, affected individuals have about half of the normal amount of this protein, which leads to the signs and symptoms of OFCD syndrome.
In individuals who have only one X chromosome in each cell (typical for males), these variants would prevent the production of any BCL6 corepressor protein. A complete lack of this protein is thought to be lethal very early in development.
More About This Health ConditionMicrophthalmia
MedlinePlus Genetics provides information about Microphthalmia
More About This Health ConditionOther Names for This Gene
- BCL-6 interacting corepressor
- BCL6 co-repressor
- BCOR_HUMAN
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
References
- Hilton EN, Manson FD, Urquhart JE, Johnston JJ, Slavotinek AM, Hedera P, Stattin EL, Nordgren A, Biesecker LG, Black GC. Left-sided embryonic expression of the BCL-6 corepressor, BCOR, is required for vertebrate laterality determination. Hum Mol Genet. 2007 Jul 15;16(14):1773-82. doi: 10.1093/hmg/ddm125. Epub 2007 May 21. Citation on PubMed
- Horn D, Chyrek M, Kleier S, Luttgen S, Bolz H, Hinkel GK, Korenke GC, Riess A, Schell-Apacik C, Tinschert S, Wieczorek D, Gillessen-Kaesbach G, Kutsche K. Novel mutations in BCOR in three patients with oculo-facio-cardio-dental syndrome, but none in Lenz microphthalmia syndrome. Eur J Hum Genet. 2005 May;13(5):563-9. doi: 10.1038/sj.ejhg.5201391. Citation on PubMed
- Huynh KD, Fischle W, Verdin E, Bardwell VJ. BCoR, a novel corepressor involved in BCL-6 repression. Genes Dev. 2000 Jul 15;14(14):1810-23. Citation on PubMed or Free article on PubMed Central
- Ng D, Thakker N, Corcoran CM, Donnai D, Perveen R, Schneider A, Hadley DW, Tifft C, Zhang L, Wilkie AO, van der Smagt JJ, Gorlin RJ, Burgess SM, Bardwell VJ, Black GC, Biesecker LG. Oculofaciocardiodental and Lenz microphthalmia syndromes result from distinct classes of mutations in BCOR. Nat Genet. 2004 Apr;36(4):411-6. doi: 10.1038/ng1321. Epub 2004 Mar 7. Citation on PubMed
- Ragge N, Isidor B, Bitoun P, Odent S, Giurgea I, Cogne B, Deb W, Vincent M, Le Gall J, Morton J, Lim D; DDD Study; Le Meur G, Zazo Seco C, Zafeiropoulou D, Bax D, Zwijnenburg P, Arteche A, Swafiri ST, Cleaver R, McEntagart M, Kini U, Newman W, Ayuso C, Corton M, Herenger Y, Jeanne M, Calvas P, Chassaing N. Expanding the phenotype of the X-linked BCOR microphthalmia syndromes. Hum Genet. 2019 Sep;138(8-9):1051-1069. doi: 10.1007/s00439-018-1896-x. Epub 2018 Jul 4. Citation on PubMed
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