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TG

TG

Reviewed May 2006

What is the official name of the TG gene?

The official name of this gene is “thyroglobulin.”

TG is the gene's official symbol. The TG 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 TG gene?

The TG gene provides instructions for making a protein called thyroglobulin, one of the largest proteins in the body. This protein is found only in the thyroid gland, a butterfly-shaped tissue in the lower neck. Thyroglobulin combines with iodine and is modified and broken down to release small molecules known as thyroid hormones. Thyroid hormones play an important role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism). Thyroglobulin also serves as a protein storehouse for iodine and inactive thyroid hormone until these substances are needed.

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

congenital hypothyroidism - caused by mutations in the TG gene

Several TG gene mutations have been identified in people with a mild to severe thyroid hormone deficiency. When the deficiency is severe enough during fetal development, it can cause congenital hypothyroidism. The mutations either delete a small segment of the TG gene or change one of the DNA building blocks (base pairs). As a result, the 3-dimensional shape of thyroglobulin is altered, reducing the amount of properly structured protein that is available for thyroid hormone production. In most affected individuals, the thyroid gland is enlarged (goiter) in an attempt to compensate for reduced hormone production.

autoimmune disorders - associated with the TG gene

A major cause of thyroid disease is autoimmunity, in which the body's immune response turns against itself. The autoimmune response is triggered by a combination of genetic and environmental factors and involves the production of large Y-shaped proteins called antibodies or immunoglobulins. Instead of attacking foreign substances such as toxins or proteins from bacteria and viruses, antibodies sometimes inappropriately attack thyroid proteins. Antibodies that attack the body's own proteins are called autoantibodies. The presence of autoantibodies to thyroglobulin is an indication of autoimmune thyroid disease.

Hashimoto thyroiditis is a common type of autoimmune thyroid disease. Individuals with Hashimoto thyroiditis may have reduced thyroid activity (hypothyroidism) and an enlarged thyroid gland (goiter). Some people with this disorder have autoantibodies to thyroglobulin.

other disorders - caused by mutations in the TG gene

TG gene mutations have also been identified in some people who have a goiter but normal or near normal thyroglobulin levels. These mutations either delete part of the TG gene or change one of the DNA building blocks (base pairs). As a result, the 3-dimensional shape of thyroglobulin is altered, reducing the amount of properly structured protein that is available for thyroid hormone production. The thyroid gland enlarges to compensate for decreased levels of thyroglobulin.

Genetics Home Reference provides information about these additional conditions, which are also associated with changes in the TG gene:

Where is the TG gene located?

Cytogenetic Location: 8q24

Molecular Location on chromosome 8: base pairs 132,866,915 to 133,134,901

The TG gene is located on the long (q) arm of chromosome 8 at position 24.

The TG gene is located on the long (q) arm of chromosome 8 at position 24.

More precisely, the TG gene is located from base pair 132,866,915 to base pair 133,134,901 on chromosome 8.

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

Where can I find additional information about TG?

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

  • AITD3
  • TGN
  • THYG_HUMAN

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 TG?

autoimmune ; autoimmunity ; bacteria ; congenital ; deficiency ; DNA ; gene ; goiter ; hormone ; hypothyroidism ; immune response ; iodine ; metabolism ; protein ; TGN ; thyroglobulin ; thyroid ; thyroid hormones ; tissue

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

See also Understanding Medical Terminology.

References (12 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: May 2006
Published: September 15, 2014