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


Reviewed August 2015

What is the official name of the TAT gene?

The official name of this gene is “tyrosine aminotransferase.”

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

What is the normal function of the TAT gene?

The TAT gene provides instructions for making a liver enzyme called tyrosine aminotransferase. This enzyme is the first in a series of five enzymes that work to break down the amino acid tyrosine, a protein building block found in many foods. Specifically, tyrosine aminotransferase converts tyrosine into a byproduct called 4-hydroxyphenylpyruvate. Continuing the process, 4-hydroxyphenylpyruvate is further broken down and ultimately smaller molecules are produced that are either excreted by the kidneys or used to produce energy or make other substances in the body.

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

tyrosinemia - caused by mutations in the TAT gene

At least 22 TAT gene mutations have been found to cause tyrosinemia type II. This condition often affects the eyes, skin, and mental development. Most of these mutations change single DNA building blocks (base pairs) within the TAT gene. Research suggests that the altered TAT gene produces a tyrosine aminotransferase enzyme with reduced activity. Other mutations delete all or part of the TAT gene, eliminating enzyme activity. As a result of these mutations, tyrosine is not properly broken down. Tyrosine levels are elevated and some tyrosine is converted into other molecules that may be toxic to cells. It is unclear how impaired break down of tyrosine leads to the skin, eye, and intellectual problems that characterize tyrosinemia type II.

Where is the TAT gene located?

Cytogenetic Location: 16q22.1

Molecular Location on chromosome 16: base pairs 71,566,851 to 71,577,095

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

The TAT gene is located on the long (q) arm of chromosome 16 at position 22.1.

The TAT gene is located on the long (q) arm of chromosome 16 at position 22.1.

More precisely, the TAT gene is located from base pair 71,566,851 to base pair 71,577,095 on chromosome 16.

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

Where can I find additional information about TAT?

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

  • L-tyrosine:2-oxoglutarate aminotransferase
  • tyrosine transaminase

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

What glossary definitions help with understanding TAT?

amino acid ; DNA ; enzyme ; gene ; L-tyrosine ; protein ; toxic ; tyrosine

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


  • Bouyacoub Y, Zribi H, Azzouz H, Nasrallah F, Abdelaziz RB, Kacem M, Rekaya B, Messaoud O, Romdhane L, Charfeddine C, Bouziri M, Bouziri S, Tebib N, Mokni M, Kaabachi N, Boubaker S, Abdelhak S. Novel and recurrent mutations in the TAT gene in Tunisian families affected with Richner-Hanhart syndrome. Gene. 2013 Oct 15;529(1):45-9. doi: 10.1016/j.gene.2013.07.066. Epub 2013 Aug 13. (
  • Mehere P, Han Q, Lemkul JA, Vavricka CJ, Robinson H, Bevan DR, Li J. Tyrosine aminotransferase: biochemical and structural properties and molecular dynamics simulations. Protein Cell. 2010 Nov;1(11):1023-32. doi: 10.1007/s13238-010-0128-5. Epub 2010 Dec 10. (
  • NCBI Gene (
  • Sivaraman S, Kirsch JF. The narrow substrate specificity of human tyrosine aminotransferase--the enzyme deficient in tyrosinemia type II. FEBS J. 2006 May;273(9):1920-9. (


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: August 2015
Published: February 1, 2016