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URL of this page: https://medlineplus.gov/genetics/gene/serpina7/

SERPINA7 gene

serpin family A member 7

Normal Function

The SERPINA7 gene provides instructions for making a protein called thyroxine-binding globulin. This protein attaches (binds) to hormones made 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). Thyroxine is the primary hormone produced by the thyroid gland. In the bloodstream, thyroid hormones are typically attached to thyroxine-binding globulin and similar proteins

Health Conditions Related to Genetic Changes

Inherited thyroxine-binding globulin deficiency

Several variants (also called mutations) in the SERPINA7 gene have been identified in people with inherited thyroxine-binding globulin deficiency, a genetic condition that typically does not cause health problems. Researchers have identified two forms of inherited thyroxine-binding globulin deficiency: the partial form and the complete form. The partial form reduces the amount of functioning thyroxine-binding globulin, while the complete form causes a more significant loss of functioning thyroxine-binding globulin.

Some SERPINA7 gene variants cause cells to produce a shortened version of thyroxine-binding globulin that does not function as it should. These genetic changes typically cause the complete form of inherited thyroxine-binding globulin deficiency. The variants in the SERPINA7 gene that cause the partial form of inherited thyroxine-binding globulin deficiency typically change a single protein building block (amino acid) in thyroxine-binding globulin. These variants lead to a reduction in the amount of functioning thyroxine-binding globulin.

When there is a shortage of thyroxine-binding globulin, the total amount of thyroxine in the bloodstream is reduced. Although thyroxine-binding globulin deficiency does not typically cause health problems, it can be mistaken for more serious thyroid disorders, such as hypothyroidism. Therefore, it is important to correctly diagnose the condition to avoid unnecessary treatments.

More About This Health Condition

Other disorders

Changes involving the SERPINA7 gene can also cause a condition called thyroxine-binding globulin excess. 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 typically does not cause health problems.

Other Names for This Gene

  • 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
  • serpin peptidase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 7
  • TBG
  • thyroxin-binding globulin
  • thyroxine-binding globulin

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases

References

  • Chakravarthy V, Ejaz S. Thyroxine-Binding Globulin Deficiency. 2023 Jul 4. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from http://www.ncbi.nlm.nih.gov/books/NBK544274/ Citation on PubMed
  • 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. Citation on PubMed
  • Fang Y, Chen H, Chen Q, Wang C, Liang L. Compound hemizygous variants in SERPINA7 gene cause thyroxine-binding globulin deficiency. Mol Genet Genomic Med. 2021 Feb;9(2):e1571. doi: 10.1002/mgg3.1571. Epub 2021 Feb 7. Citation on PubMed
  • 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. doi: 10.1210/mend.7.8.8232304. Citation on PubMed
  • 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. doi: 10.1210/jcem.80.12.8530630. Citation on PubMed
  • Pappa T, Ferrara AM, Refetoff S. Inherited defects of thyroxine-binding proteins. Best Pract Res Clin Endocrinol Metab. 2015 Oct;29(5):735-47. doi: 10.1016/j.beem.2015.09.002. Epub 2015 Sep 30. Citation on PubMed
  • Schussler GC. The thyroxine-binding proteins. Thyroid. 2000 Feb;10(2):141-9. doi: 10.1089/thy.2000.10.141. Erratum In: Thyroid 2000 Apr;10(4):372. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.