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Genetics Home Reference: your guide to understanding genetic conditions
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SERPINA7

Reviewed September 2009

What is the official name of the SERPINA7 gene?

The official name of this gene is “serpin peptidase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 7.”

SERPINA7 is the gene's official symbol. The SERPINA7 gene is also known by other names, listed below.

What is the normal function of the SERPINA7 gene?

The SERPINA7 gene (also known as TBG) provides instructions for making a protein called thyroxine-binding globulin. In the bloodstream, this protein carries hormones made or used by the thyroid gland, which is a butterfly-shaped tissue in the lower neck. Thyroid hormones play an important role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism). Most of the time, thyroid hormones circulate in the bloodstream attached to thyroxine-binding globulin and similar proteins.

Does the SERPINA7 gene share characteristics with other genes?

The SERPINA7 gene belongs to a family of genes called SERPIN (serine (or cysteine) peptidase inhibitors).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.

How are changes in the SERPINA7 gene related to health conditions?

inherited thyroxine-binding globulin deficiency - caused by mutations in the SERPINA7 gene

More than 25 mutations in the SERPINA7 gene have been identified in people with inherited thyroxine-binding globulin deficiency. Some mutations lead to a shortened, nonfunctional version of thyroxine-binding globulin. These genetic changes result in a total loss of the protein, which causes the complete form of inherited thyroxine-binding globulin deficiency (TBG-CD). Other mutations change single protein building blocks (amino acids) in thyroxine-binding globulin. These mutations alter the structure or processing of the protein, leading to the partial form of the disorder (TBG-PD).

When there is a shortage of thyroxine-binding globulin, the amount of circulating thyroid hormones is reduced. These changes do not cause any problems with thyroid function. Although inherited thyroxine-binding globulin deficiency does not cause any health problems, it can be mistaken for more serious thyroid disorders (such as hypothyroidism). Therefore, it is important to diagnose inherited thyroxine-binding globulin deficiency to avoid unnecessary treatments.

other disorders - caused by mutations in the SERPINA7 gene

Other changes involving the SERPINA7 gene cause a condition called thyroxine-binding globulin excess (TBG-E). People with this condition have unusually high levels of thyroxine-binding globulin, often two to four times greater than normal. This excess is caused by the presence of one or more extra copies of the SERPINA7 gene in each cell. Like thyroxine-binding globulin deficiency, thyroxine-binding globulin excess does not cause any problems with thyroid function.

Where is the SERPINA7 gene located?

Cytogenetic Location: Xq22.2

Molecular Location on the X chromosome: base pairs 105,277,189 to 105,282,717

The SERPINA7 gene is located on the long (q) arm of the X chromosome at position 22.2.

The SERPINA7 gene is located on the long (q) arm of the X chromosome at position 22.2.

More precisely, the SERPINA7 gene is located from base pair 105,277,189 to base pair 105,282,717 on the X chromosome.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about SERPINA7?

You and your healthcare professional may find the following resources about SERPINA7 helpful.

  • Educational resources - Information pages

    • Endocrinology (2001): Transport and metabolism of thyroid hormones (http://www.ncbi.nlm.nih.gov/books/NBK28/)
    • Thyroid Disease Manager: Abnormal Thyroid Hormone Transport (http://www.thyroidmanager.org/chapter/abnormal-thyroid-hormone-transport/)

You may also be interested in these resources, which are designed for genetics professionals and researchers.

  • PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=(SERPINA7%5BTIAB%5D)%20OR%20((TBG%5BTI%5D)%20OR%20(thyroxin-binding%20globulin%5BTI%5D)%20OR%20(thyroxine-binding%20globulin%5BTI%5D))%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D%20AND%20%22last%203240%20days%22%5Bdp%5D)
  • OMIM - Genetic disorder catalog (http://omim.org/entry/314200)

  • Research Resources - Tools for researchers

    • Entrez Gene (http://www.ncbi.nlm.nih.gov/gene/6906)
    • GeneCards (http://www.genecards.org/cgi-bin/carddisp.pl?id_type=entrezgene&id=6906)
    • HUGO Gene Nomenclature Committee (http://www.genenames.org/data/hgnc_data.php?hgnc_id=11583)

What other names do people use for the SERPINA7 gene or gene products?

  • alpha-1 antiproteinase, antitrypsin
  • serine (or cysteine) proteinase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 7
  • serine (or cysteine) proteinase inhibitor, clade A, member 7
  • TBG
  • THBG_HUMAN
  • thyroxin-binding globulin
  • thyroxine-binding globulin

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding SERPINA7?

acids ; cell ; deficiency ; gene ; gene amplification ; hypothyroidism ; metabolism ; protein ; proteinase ; serine ; T3 ; thyroid ; thyroid hormones ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Domingues R, Font P, Sobrinho L, Bugalho MJ. A novel variant in Serpina7 gene in a family with thyroxine-binding globulin deficiency. Endocrine. 2009 Aug;36(1):83-6. doi: 10.1007/s12020-009-9202-2. Epub 2009 May 5. (http://www.ncbi.nlm.nih.gov/pubmed/19415532?dopt=Abstract)
  • Entrez Gene (http://www.ncbi.nlm.nih.gov/gene/6906)
  • Hayashi Y, Mori Y, Janssen OE, Sunthornthepvarakul T, Weiss RE, Takeda K, Weinberg M, Seo H, Bell GI, Refetoff S. Human thyroxine-binding globulin gene: complete sequence and transcriptional regulation. Mol Endocrinol. 1993 Aug;7(8):1049-60. (http://www.ncbi.nlm.nih.gov/pubmed/8232304?dopt=Abstract)
  • Mori Y, Miura Y, Takeuchi H, Igarashi Y, Sugiura J, Saito H, Oiso Y. Gene amplification as a cause of inherited thyroxine-binding globulin excess in two Japanese families. J Clin Endocrinol Metab. 1995 Dec;80(12):3758-62. (http://www.ncbi.nlm.nih.gov/pubmed/8530630?dopt=Abstract)
  • Schussler GC. The thyroxine-binding proteins. Thyroid. 2000 Feb;10(2):141-9. Review. Erratum in: Thyroid 2000 Apr;10(4):372. (http://www.ncbi.nlm.nih.gov/pubmed/10718550?dopt=Abstract)
  • Thyroid Disease Manager: Abnormal Thyroid Hormone Transport (http://www.thyroidmanager.org/chapter/abnormal-thyroid-hormone-transport/)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: September 2009
Published: May 13, 2013