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Genetics Home Reference: your guide to understanding genetic conditions
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TYR

Reviewed March 2007

What is the official name of the TYR gene?

The official name of this gene is “tyrosinase.”

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

What is the normal function of the TYR gene?

The TYR gene provides instructions for making an enzyme called tyrosinase. This enzyme is located in melanocytes, which are specialized cells that produce a pigment called melanin. Melanin is the substance that gives skin, hair, and eyes their color. Melanin is also found in the light-sensitive tissue at the back of the eye (the retina), where it plays a role in normal vision.

Tyrosinase is responsible for the first step in melanin production. It converts a protein building block (amino acid) called tyrosine to another compound called dopaquinone. A series of additional chemical reactions convert dopaquinone to melanin in the skin, hair follicles, the colored part of the eye (the iris), and the retina.

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

oculocutaneous albinism - caused by mutations in the TYR gene

More than 100 mutations in the TYR gene have been identified in people with oculocutaneous albinism type 1. These mutations disrupt the normal production of melanin, which reduces coloring of the hair, skin, and eyes and causes problems with vision. Most TYR mutations eliminate the activity of tyrosinase, preventing melanocytes from producing any melanin throughout life. These mutations cause a form of oculocutaneous albinism called type 1A (OCA1A). People with this form of albinism have white hair, light-colored eyes, and very pale skin that does not tan. Other mutations in the TYR gene reduce but do not eliminate tyrosinase activity. These mutations, which allow some melanin to be produced, cause oculocutaneous albinism type 1B (OCA1B). People with type 1B are also born with white hair, light-colored eyes, and pale skin, but hair and eye color often darken over time and skin may tan.

Where is the TYR gene located?

Cytogenetic Location: 11q14.3

Molecular Location on chromosome 11: base pairs 89,177,871 to 89,295,758

The TYR gene is located on the long (q) arm of chromosome 11 at position 14.3.

The TYR gene is located on the long (q) arm of chromosome 11 at position 14.3.

More precisely, the TYR gene is located from base pair 89,177,871 to base pair 89,295,758 on chromosome 11.

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 TYR?

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

  • LB24-AB
  • Monophenol monooxygenase
  • OCA1A
  • OCAIA
  • SK29-AB
  • Tumor Rejection Antigen AB
  • TYRO_HUMAN

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 TYR?

albinism ; amino acid ; compound ; enzyme ; gene ; melanin ; melanocytes ; melanosome ; pigment ; protein ; retina ; tissue ; tumor ; Tyr ; tyrosine

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

References

  • Gene Review: Oculocutaneous Albinism Type 1 (http://www.ncbi.nlm.nih.gov/books/NBK1166)
  • King RA, Pietsch J, Fryer JP, Savage S, Brott MJ, Russell-Eggitt I, Summers CG, Oetting WS. Tyrosinase gene mutations in oculocutaneous albinism 1 (OCA1): definition of the phenotype. Hum Genet. 2003 Nov;113(6):502-13. Epub 2003 Sep 10. (http://www.ncbi.nlm.nih.gov/pubmed/13680365?dopt=Abstract)
  • Murisier F, Beermann F. Genetics of pigment cells: lessons from the tyrosinase gene family. Histol Histopathol. 2006 May;21(5):567-78. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16493586?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/7299)
  • Oetting WS, Fryer JP, Shriram S, King RA. Oculocutaneous albinism type 1: the last 100 years. Pigment Cell Res. 2003 Jun;16(3):307-11. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12753405?dopt=Abstract)
  • Oetting WS. The tyrosinase gene and oculocutaneous albinism type 1 (OCA1): A model for understanding the molecular biology of melanin formation. Pigment Cell Res. 2000 Oct;13(5):320-5. Review. (http://www.ncbi.nlm.nih.gov/pubmed/11041207?dopt=Abstract)
  • Opitz S, Käsmann-Kellner B, Kaufmann M, Schwinger E, Zühlke C. Detection of 53 novel DNA variations within the tyrosinase gene and accumulation of mutations in 17 patients with albinism. Hum Mutat. 2004 Jun;23(6):630-1. (http://www.ncbi.nlm.nih.gov/pubmed/15146472?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: March 2007
Published: November 24, 2014