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TPO

TPO

Reviewed August 2015

What is the official name of the TPO gene?

The official name of this gene is “thyroid peroxidase.”

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

The TPO gene provides instructions for making an enzyme called thyroid peroxidase. This enzyme plays a central role in the function of the thyroid gland, a butterfly-shaped tissue in the lower neck. Thyroid peroxidase assists the chemical reaction that adds iodine to a protein called thyroglobulin, a critical step in generating thyroid hormones. Thyroid hormones play an important role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism).

To function properly, thyroid peroxidase must be located in the cell membrane of certain thyroid cells, called follicular cells. Thyroid peroxidase has several different versions (isoforms), which vary by size and location within the cell. Some versions do not function because they are not located in the cell membrane.

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

congenital hypothyroidism - caused by mutations in the TPO gene

TPO gene mutations can cause congenital hypothyroidism, a condition characterized by abnormally low levels of thyroid hormones starting from birth. The TPO gene mutations involved in this condition delete, add, or change DNA building blocks (base pairs) in the TPO gene. Some mutations lead to an abnormally small thyroid peroxidase enzyme that breaks apart before it can be inserted into the cell membrane. Other mutations change the enzyme's 3-dimensional shape, preventing it from functioning properly within the cell membrane. Without functional thyroid peroxidase, iodine taken up by the thyroid gland is not added to thyroglobulin. As a result, the production of thyroid hormones is absent or reduced, leading to the features of congenital hypothyroidism. In most affected individuals, the thyroid gland is enlarged (goiter) in an attempt to compensate for reduced hormone production. Because cases caused by TPO gene mutations result from a disruption of thyroid hormone synthesis, they are classified as thyroid dyshormonogenesis.

Where is the TPO gene located?

Cytogenetic Location: 2p25

Molecular Location on chromosome 2: base pairs 1,413,460 to 1,542,726

The TPO gene is located on the short (p) arm of chromosome 2 at position 25.

The TPO gene is located on the short (p) arm of chromosome 2 at position 25.

More precisely, the TPO gene is located from base pair 1,413,460 to base pair 1,542,726 on chromosome 2.

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

Where can I find additional information about TPO?

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

  • MSA
  • PERT_HUMAN
  • thyroid microsomal antigen
  • thyroperoxidase
  • TPX

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 TPO?

autoimmune ; cell ; cell membrane ; congenital ; DNA ; enzyme ; gene ; goiter ; hormone ; hypothyroidism ; iodine ; isoforms ; metabolism ; protein ; synthesis ; 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 (9 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: August 24, 2015