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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.

Read more about gene names and symbols on the About page.

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 171,635,417 to 171,652,633

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

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 171,635,417 to base pair 171,652,633 on chromosome 1.

See How do geneticists indicate the location of a gene? 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
  • TIGR
  • trabecular meshwork-induced glucocorticoid response protein

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

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.

See also Understanding Medical Terminology.

References (15 links)


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: February 2009
Published: February 8, 2016