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Genetics Home Reference: your guide to understanding genetic conditions
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MYOC

Reviewed February 2009

What is the official name of the MYOC gene?

The official name of this gene is “myocilin, trabecular meshwork inducible glucocorticoid response.”

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

What is the normal function of the MYOC gene?

The MYOC gene provides instructions for producing a protein called myocilin. Myocilin is found in certain structures of the eye, called the trabecular meshwork and the ciliary body, that regulate the pressure within the eye (intraocular pressure). It is also found in various types of muscle. Myocilin's function is not well understood, but it may help to control the intraocular pressure through its action in the muscle tissue of the ciliary body.

Researchers believe that myocilin functions together with other proteins as part of a protein complex. Myocilin may interact with a number of other proteins including a form of the cytochrome P450 protein, the product of the CYP1B1 gene. Like myocilin, this protein is found in the trabecular meshwork, ciliary body, and other structures of the eye.

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

early-onset glaucoma - caused by mutations in the MYOC gene

Approximately 10 percent to 33 percent of people with juvenile open-angle glaucoma have mutations in the MYOC gene. MYOC gene mutations have also been detected in some people with primary congenital glaucoma. More than 40 MYOC gene mutations have been identified.

Mutations in the MYOC gene may alter the myocilin protein so that its interactions with other proteins are impeded. Defective myocilin that is not incorporated into protein complexes may accumulate in the trabecular meshwork and ciliary body. The excess protein may prevent sufficient flow of fluid from the eye, resulting in increased intraocular pressure and causing the signs and symptoms of early-onset glaucoma.

Individuals with mutations in both the MYOC and CYP1B1 genes may develop glaucoma at an earlier age than do those with mutations in only one of the genes.

other disorders - caused by mutations in the MYOC gene

A small percentage of individuals with late-onset primary open-angle glaucoma (POAG), the most common adult form of glaucoma, have mutations in the MYOC gene. Most cases of this condition, however, are caused by other diseases, aging, and lifestyle factors such as smoking.

Where is the MYOC gene located?

Cytogenetic Location: 1q23-q24

Molecular Location on chromosome 1: base pairs 171,635,416 to 171,652,632

The MYOC gene is located on the long (q) arm of chromosome 1 between positions 23 and 24.

The MYOC gene is located on the long (q) arm of chromosome 1 between positions 23 and 24.

More precisely, the MYOC gene is located from base pair 171,635,416 to base pair 171,652,632 on chromosome 1.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about MYOC?

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

  • GLC1A
  • GPOA
  • JOAG
  • JOAG1
  • MYOC_HUMAN
  • TIGR
  • trabecular meshwork-induced glucocorticoid response protein

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding MYOC?

ciliary body ; congenital ; cytochrome P450 ; gene ; glaucoma ; glucocorticoid ; intraocular ; juvenile ; protein ; tissue ; trabecular meshwork

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Bayat B, Yazdani S, Alavi A, Chiani M, Chitsazian F, Tusi BK, Suri F, Narooie-Nejhad M, Sanati MH, Elahi E. Contributions of MYOC and CYP1B1 mutations to JOAG. Mol Vis. 2008 Mar 13;14:508-17. (http://www.ncbi.nlm.nih.gov/pubmed/18385784?dopt=Abstract)
  • Chen Y, Jiang D, Yu L, Katz B, Zhang K, Wan B, Sun X. CYP1B1 and MYOC mutations in 116 Chinese patients with primary congenital glaucoma. Arch Ophthalmol. 2008 Oct;126(10):1443-7. doi: 10.1001/archopht.126.10.1443. (http://www.ncbi.nlm.nih.gov/pubmed/18852424?dopt=Abstract)
  • OMIM: GLAUCOMA, PRIMARY OPEN ANGLE (http://omim.org/entry/137760)
  • Joe MK, Sohn S, Hur W, Moon Y, Choi YR, Kee C. Accumulation of mutant myocilins in ER leads to ER stress and potential cytotoxicity in human trabecular meshwork cells. Biochem Biophys Res Commun. 2003 Dec 19;312(3):592-600. (http://www.ncbi.nlm.nih.gov/pubmed/14680806?dopt=Abstract)
  • Kanagavalli J, Pandaranayaka E, Krishnadas SR, Krishnaswamy S, Sundaresan P. A review of genetic and structural understanding of the role of myocilin in primary open angle glaucoma. Indian J Ophthalmol. 2004 Dec;52(4):271-80. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15693317?dopt=Abstract)
  • Kaur K, Reddy AB, Mukhopadhyay A, Mandal AK, Hasnain SE, Ray K, Thomas R, Balasubramanian D, Chakrabarti S. Myocilin gene implicated in primary congenital glaucoma. Clin Genet. 2005 Apr;67(4):335-40. (http://www.ncbi.nlm.nih.gov/pubmed/15733270?dopt=Abstract)
  • Kong TH. Post-transcriptional modification of the gene genetically linked to juvenile open-angle glaucoma; novel transcripts in human ocular tissues. Gene. 2001 Dec 12;280(1-2):115-22. (http://www.ncbi.nlm.nih.gov/pubmed/11738824?dopt=Abstract)
  • OMIM: MYOCILIN (http://omim.org/entry/601652)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/4653)
  • Polansky JR, Fauss DJ, Zimmerman CC. Regulation of TIGR/MYOC gene expression in human trabecular meshwork cells. Eye (Lond). 2000 Jun;14 ( Pt 3B):503-14. (http://www.ncbi.nlm.nih.gov/pubmed/11026980?dopt=Abstract)
  • Polansky JR. Current perspectives on the TIGR/MYOC gene (Myocilin) and glaucoma. Ophthalmol Clin North Am. 2003 Dec;16(4):515-27, v-vi. Review. (http://www.ncbi.nlm.nih.gov/pubmed/14740993?dopt=Abstract)
  • Ray K, Mukhopadhyay A, Acharya M. Recent advances in molecular genetics of glaucoma. Mol Cell Biochem. 2003 Nov;253(1-2):223-31. Review. (http://www.ncbi.nlm.nih.gov/pubmed/14619973?dopt=Abstract)
  • Vincent AL, Billingsley G, Buys Y, Levin AV, Priston M, Trope G, Williams-Lyn D, Héon E. Digenic inheritance of early-onset glaucoma: CYP1B1, a potential modifier gene. Am J Hum Genet. 2002 Feb;70(2):448-60. Epub 2002 Jan 3. (http://www.ncbi.nlm.nih.gov/pubmed/11774072?dopt=Abstract)
  • Weisschuh N, Schiefer U. Progress in the genetics of glaucoma. Dev Ophthalmol. 2003;37:83-93. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12876831?dopt=Abstract)
  • WuDunn D. Genetic basis of glaucoma. Curr Opin Ophthalmol. 2002 Apr;13(2):55-60. Review. (http://www.ncbi.nlm.nih.gov/pubmed/11880716?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: February 2009
Published: December 22, 2014