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    TPO Gene

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    Submitted by: Rui Liu
    (This entry belongs to Entry Collection "MedlinePlus ")

    Definition

    Thyroid peroxidase: The TPO gene provides instructions for making an enzyme called thyroid peroxidase.

    1. Normal Function

    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.

    2. Health Conditions Related to Genetic Changes

    2.1. Congenital hypothyroidism

    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.

    3. Other Names for This Gene

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

    The entry is from https://medlineplus.gov/genetics/gene/tpo

    References

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    2. Cangul H, Aycan Z, Olivera-Nappa A, Saglam H, Schoenmakers NA, Boelaert K,Cetinkaya S, Tarim O, Bober E, Darendeliler F, Bas V, Demir K, Aydin BK, Kendall M, Cole T, Högler W, Chatterjee VK, Barrett TG, Maher ER. Thyroiddyshormonogenesis is mainly caused by TPO mutations in consanguineous community. Clin Endocrinol (Oxf). 2013 Aug;79(2):275-81. doi: 10.1111/cen.12127.
    3. Chardès T, Chapal N, Bresson D, Bès C, Giudicelli V, Lefranc MP, Péraldi-Roux S. The human anti-thyroid peroxidase autoantibody repertoire in Graves' andHashimoto's autoimmune thyroid diseases. Immunogenetics. 2002 Jun;54(3):141-57.
    4. Kotani T, Umeki K, Kawano J, Suganuma T, Hishinuma A, Ieiri T, Harada S.Partial iodide organification defect caused by a novel mutation of the thyroidperoxidase gene in three siblings. Clin Endocrinol (Oxf). 2003 Aug;59(2):198-206.
    5. Lee CC, Harun F, Jalaludin MY, Lim CY, Ng KL, Mat Junit S. Functional analysesof C.2268dup in thyroid peroxidase gene associated with goitrous congenitalhypothyroidism. Biomed Res Int. 2014;2014:370538. doi: 10.1155/2014/370538.
    6. Nascimento AC, Guedes DR, Santos CS, Knobel M, Rubio IG, Medeiros-Neto G.Thyroperoxidase gene mutations in congenital goitrous hypothyroidism with totaland partial iodide organification defect. Thyroid. 2003 Dec;13(12):1145-51.
    7. Rivolta CM, Esperante SA, Gruñeiro-Papendieck L, Chiesa A, Moya CM, Domené S, Varela V, Targovnik HM. Five novel inactivating mutations in the thyroidperoxidase gene responsible for congenital goiter and iodide organificationdefect. Hum Mutat. 2003 Sep;22(3):259.
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