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Disease Profile

Hereditary antithrombin deficiency

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Congenital AT-III deficiency; Antithrombin III Deficiency; Congenital Antithrombin III Deficiency;


Blood Diseases; Congenital and Genetic Diseases; Musculoskeletal Diseases


Hereditary antithrombin deficiency, also known as antithrombin III deficiency or AT III deficiency, is a disorder in which individuals are at increased risk for developing blood clots. The type of blood clots seen in individuals with this condition are typically clots that form in the deep veins of the leg (deep vein thrombosis or DVT) and clots that lodge in the lungs (pulmonary embolism or PE). Approximately 50% of individuals with hereditary antithrombin deficiency will develop one or more clots in their lifetime, usually after adolescence. Factors that may increase the likelihood of clotting include pregnancy, the use of oral contraceptives, surgery, increasing age, and a lack of movement. Hereditary antithrombin deficiency is caused by mutations in the SERPINC1 gene and is typically inherited in an autosomal dominant manner.[1][2]


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Reduced antithrombin antigen
Reduced antithrombin III activity
30%-79% of people have these symptoms
Deep venous thrombosis
Blood clot in a deep vein
Pregnancy exposure
Pulmonary embolism
Blood clot in artery of lung
Recurrent thromboembolism
Superficial thrombophlebitis
5%-29% of people have these symptoms
Arterial thrombosis
Blood clot in artery
Hepatic vein thrombosis
Blood clot in liver vein
Mesenteric venous thrombosis
Portal vein thrombosis
Blood clot in portal vein
Recurrent spontaneous abortion
Retinal vein occlusion
1%-4% of people have these symptoms
Cerebral venous thrombosis
Blood clot in cerebral vein
Percent of people who have these symptoms is not available through HPO
Arterial occlusion
Autosomal dominant inheritance
Autosomal recessive inheritance
Recurrent thrombophlebitis


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    Once a patient with hereditary antithrombin deficiency develops a clot, anticoagulation therapy (usually Warfarin) is often indicated. The duration of therapy after a first clot, especially in children, is a matter of some controversy, but therapy is generally continued for 3-6 months. Individuals who experience a second clot are at a significant risk for future clotting and are candidates for long-term Warfarin therapy. Asymptomatic individuals are often not treated with anticoagulation therapy. Should surgery be necessary, individuals with hereditary antithrombin deficiency may receive antithrombin III concentrate or fresh frozen plasma to boost antithrombin levels.[3]

    FDA-Approved Treatments

    The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.


    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Organizations Providing General Support

        Learn more

        These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

        Where to Start

        • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
        • Genetics Home Reference (GHR) contains information on Hereditary antithrombin deficiency. This website is maintained by the National Library of Medicine.

          In-Depth Information

          • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.


            1. Hereditary antithrombin deficiency. Genetics Home Reference. February, 2013; https://ghr.nlm.nih.gov/condition/hereditary-antithrombin-deficiency. Accessed 8/5/2015.
            2. Bauer, Kenneth. Antithrombin Deficiency. National Organization for Rare Disorders (NORD). 2015; https://rarediseases.org/rare-diseases/antithrombin-deficiency/. Accessed 8/5/2015.
            3. Harper, James. Antithrombin III Deficiency. Medscape Reference. July 10, 2015; https://emedicine.medscape.com/article/954688-overview. Accessed 8/5/2015.
            4. Harper, James. Antithrombin III Deficiency. Medscape Reference. July 10, 2015; https://emedicine.medscape.com/article/954688-overview. Accessed 8/5/2015.

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