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


Reviewed May 2008

What is the official name of the BCOR gene?

The official name of this gene is “BCL6 corepressor.”

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

What is the normal function of the BCOR gene?

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 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 gene plays an important role in the function and survival of certain immune system cells.

Researchers have found that the BCOR gene is active throughout the body, not just in the immune system. This widespread activity suggests that the BCL6 corepressor has other functions in addition to its interaction with the BCL6 protein. The BCL6 corepressor appears to play a critical role in early embryonic 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.

Does the BCOR gene share characteristics with other genes?

The BCOR gene belongs to a family of genes called ANKRD (ankyrin repeat domain containing).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

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

Lenz microphthalmia syndrome - caused by mutations in the BCOR gene

A mutation in the BCOR gene has been found in one family with Lenz microphthalmia syndrome. This mutation changes a single protein building block (amino acid) in the BCL6 corepressor, which alters the protein's structure. Specifically, the mutation replaces the amino acid proline with the amino acid leucine at position 85 (written as Pro85Leu). Because the BCL6 corepressor plays an essential role in early development, a defective version of the protein disrupts the normal formation of the eyes and several other organs and tissues before birth.

The BCOR gene is on the X chromosome (one of the two sex chromosomes) and the inheritance of Lenz microphthalmia is described as X-linked recessive. X-linked recessive disorders occur much more commonly in males than in females. Lenz microphthalmia syndrome has been found only in males.

oculofaciocardiodental syndrome - caused by mutations in the BCOR gene

Mutations in the BCOR gene can also cause oculofaciocardiodental (OFCD) syndrome. Some of these mutations delete large amounts of genetic material from the BCOR gene, while other mutations 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.

Unlike Lenz microphthalmia syndrome, which has been found only in males, OFCD syndrome occurs exclusively in females. OFCD syndrome has an X-linked dominant inheritance pattern, which means 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. In males, who have only one X chromosome in each cell, these mutations result in a total loss of the BCL6 corepressor. A lack of this protein appears to be lethal very early in development, so no males are born with OFCD syndrome. In females, who have two X chromosomes in each cell, some cells produce a normal amount of BCL6 corepressor protein and other cells produce none. The resulting overall reduction in the amount of this protein leads to the signs and symptoms of OFCD syndrome.

Where is the BCOR gene located?

Cytogenetic Location: Xp11.4

Molecular Location on the X chromosome: base pairs 40,051,246 to 40,177,390

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

The BCOR gene is located on the short (p) arm of the X chromosome at position 11.4.

The BCOR gene is located on the short (p) arm of the X chromosome at position 11.4.

More precisely, the BCOR gene is located from base pair 40,051,246 to base pair 40,177,390 on the X chromosome.

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

Where can I find additional information about BCOR?

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

  • 5830466J11Rik
  • 8430401K06Rik
  • ANOP2
  • BCL6 co-repressor
  • BCL-6 interacting corepressor
  • FLJ20285
  • FLJ38041
  • KIAA1575
  • MAA2
  • MCOPS2
  • MGC131961
  • MGC71031

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

What glossary definitions help with understanding BCOR?

amino acid ; cell ; chromosome ; corepressor ; co-repressor ; DNA ; embryo ; embryonic ; gene ; immune system ; inheritance ; inheritance pattern ; leucine ; mutation ; proline ; protein ; recessive ; repressor ; sex chromosomes ; syndrome ; X-linked dominant ; X-linked recessive

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


  • Gene Review: Lenz Microphthalmia Syndrome (
  • 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. Epub 2007 May 21. (
  • Horn D, Chyrek M, Kleier S, Lüttgen 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. (
  • 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. (
  • NCBI Gene (
  • 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. Epub 2004 Mar 7. (


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: May 2008
Published: February 1, 2016