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TG

TG

Reviewed August 2015

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

Mutations in the TG gene can cause congenital hypothyroidism, a condition characterized by abnormally low levels of thyroid hormones starting from birth. The TG gene mutations involved in this condition 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. Because cases caused by TG gene mutations are due to a disruption of thyroid hormone synthesis, they are classified as thyroid dyshormonogenesis.

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 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, forming a goiter, to compensate for decreased levels of thyroglobulin. With this compensation, thyroid hormone levels are normal, so affected individuals do not have other signs and symptoms of congenital hypothyroidism (described above). It is unclear why enlargement of the thyroid gland can compensate in some affected individuals but not others (leading to congenital hypothyroidism).

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

Where is the TG gene located?

Cytogenetic Location: 8q24

Molecular Location on chromosome 8: base pairs 132,866,934 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 132,866,934 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?

congenital ; DNA ; DNA base ; gene ; goiter ; hormone ; hypothyroidism ; iodine ; metabolism ; protein ; synthesis ; 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: August 2015
Published: September 1, 2015