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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed August 2009

What is the official name of the SERPINC1 gene?

The official name of this gene is “serpin peptidase inhibitor, clade C (antithrombin), member 1.”

SERPINC1 is the gene's official symbol. The SERPINC1 gene is also known by other names, listed below.

What is the normal function of the SERPINC1 gene?

The SERPINC1 gene provides instructions for making a protein called antithrombin (previously known as antithrombin III), which is a type of serine protease inhibitor (serpin). Serpins help control several types of chemical reactions by blocking the activity of certain proteins. Antithrombin is found in the bloodstream and is important for controlling blood clotting.

Antithrombin blocks the activity of proteins that promote blood clotting, especially a protein called thrombin. Antithrombin attaches (binds) to thrombin and certain other clotting proteins, which are then cleared from the bloodstream by the liver.

While one part of antithrombin binds to thrombin and other clotting proteins, another part of the protein binds to a substance called heparin. Antithrombin changes its shape when it binds to heparin. This change in shape allows antithrombin to inactivate clotting proteins at a much faster rate.

Does the SERPINC1 gene share characteristics with other genes?

The SERPINC1 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? ( in the Handbook.

How are changes in the SERPINC1 gene related to health conditions?

hereditary antithrombin deficiency - caused by mutations in the SERPINC1 gene

At least 220 mutations in the SERPINC1 gene have been found to cause hereditary antithrombin deficiency. Most of these mutations change single protein building blocks (amino acids) in antithrombin, which disrupts its ability to control blood clotting.

Hereditary antithrombin deficiency can be divided into type I and type II based on the mutation in the SERPINC1 gene.

Hereditary antithrombin deficiency type I is caused by SERPINC1 gene mutations that prevent the cell from producing antithrombin from the altered gene. Individuals with this type have only one working copy of the SERPINC1 gene in each cell, which results in approximately half of the normal amount of antithrombin. Affected individuals do not have enough antithrombin to inactivate clotting proteins, which causes the increased risk for abnormal blood clots in hereditary antithrombin deficiency.

Mutations that cause hereditary antithrombin deficiency type II result in the production of an altered antithrombin with reduced activity. Individuals with this form of the condition typically have normal levels of antithrombin, but the protein does not function properly. Type II can be further divided based on whether the mutation affects binding to thrombin and other clotting factors (type IIa), heparin (type IIb), or both (type IIc). Individuals with hereditary antithrombin deficiency type IIb have a lower risk of forming an abnormal blood clot than people with other forms of this condition because antithrombin is able to inactivate clotting proteins without heparin.

Where is the SERPINC1 gene located?

Cytogenetic Location: 1q25.1

Molecular Location on chromosome 1: base pairs 173,903,800 to 173,917,378

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The SERPINC1 gene is located on the long (q) arm of chromosome 1 at position 25.1.

The SERPINC1 gene is located on the long (q) arm of chromosome 1 at position 25.1.

More precisely, the SERPINC1 gene is located from base pair 173,903,800 to base pair 173,917,378 on chromosome 1.

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

Where can I find additional information about SERPINC1?

You and your healthcare professional may find the following resources about SERPINC1 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 SERPINC1 gene or gene products?

  • antithrombin (aa 375-432)
  • antithrombin III
  • AT3
  • coding sequence signal peptide antithrombin part 1
  • heparin cofactor I
  • MGC22579
  • serine-cysteine proteinase inhibitor clade C member 1
  • serine (or cysteine) proteinase inhibitor, clade C (antithrombin), member 1
  • serpin peptidase inhibitor, clade C, member 1
  • signal peptide antithrombin part 1

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding SERPINC1?

acids ; blood clotting ; cell ; clotting ; cofactor ; cysteine ; deficiency ; gene ; hereditary ; mutation ; peptide ; protease ; protein ; proteinase ; serine ; thrombin

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Brouwer JL, Lijfering WM, Ten Kate MK, Kluin-Nelemans HC, Veeger NJ, van der Meer J. High long-term absolute risk of recurrent venous thromboembolism in patients with hereditary deficiencies of protein S, protein C or antithrombin. Thromb Haemost. 2009 Jan;101(1):93-9. (
  • Maclean PS, Tait RC. Hereditary and acquired antithrombin deficiency: epidemiology, pathogenesis and treatment options. Drugs. 2007;67(10):1429-40. Review. (
  • NCBI Gene (
  • Patnaik MM, Moll S. Inherited antithrombin deficiency: a review. Haemophilia. 2008 Nov;14(6):1229-39. doi: 10.1111/j.1365-2516.2008.01830.x. Review. (
  • Picard V, Nowak-Göttl U, Biron-Andreani C, Fouassier M, Frere C, Goualt-Heilman M, de Maistre E, Regina S, Rugeri L, Ternisien C, Trichet C, Vergnes C, Aiach M, Alhenc-Gelas M. Molecular bases of antithrombin deficiency: twenty-two novel mutations in the antithrombin gene. Hum Mutat. 2006 Jun;27(6):600. Erratum in: Hum Mutat. 2006 Nov;27(11):1160. (


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 2009
Published: February 8, 2016