What is the definition of Congenital Antithrombin 3 Deficiency?

Congenital antithrombin III deficiency is a genetic disorder that causes the blood to clot more than normal.

What are the alternative names for Congenital Antithrombin 3 Deficiency?

Deficiency - antithrombin III - congenital; Antithrombin III deficiency - congenital

What are the causes for Congenital Antithrombin 3 Deficiency?

Antithrombin III is a protein in the blood that blocks abnormal blood clots from forming. It helps the body keep a healthy balance between bleeding and clotting. Congenital antithrombin III deficiency is an inherited disease. It occurs when a person receives one abnormal copy of the antithrombin III gene from a parent with the disease.

The abnormal gene leads to a low level of the antithrombin III protein. This low level of antithrombin III can cause abnormal blood clots (thrombi) that can block blood flow and damage organs.

People with this condition will often have a blood clot at a young age. They are also likely to have family members who have had a blood clotting problem.

What are the symptoms for Congenital Antithrombin 3 Deficiency?

People will usually have symptoms of a blood clot. Blood clots in the arms or legs usually cause swelling, redness, and pain. When a blood clot breaks off from where it formed and travels to another part of the body, it is called a thromboembolism. Symptoms depend on where the blood clot travels to. A common place is the lung, where the clot can cause a cough, shortness of breath, pain while taking deep breaths, chest pain, and even death. Blood clots that travel to the brain can cause a stroke.

What are the current treatments for Congenital Antithrombin 3 Deficiency?

A blood clot is treated with blood-thinning medicines (also called anticoagulants). How long you need to take these drugs depends on how serious the blood clot was and other factors. Discuss this with your provider.

What are the support groups for Congenital Antithrombin 3 Deficiency?

These resources can provide more information on congenital antithrombin III deficiency:

  • National Organization for Rare Disorders -- rarediseases.org/rare-diseases/antithrombin-deficiency
  • NLM Genetics Home Reference -- ghr.nlm.nih.gov/condition/hereditary-antithrombin-deficiency

What is the outlook (prognosis) for Congenital Antithrombin 3 Deficiency?

Most people have a good outcome if they stay on anticoagulant medicines.

What are the possible complications for Congenital Antithrombin 3 Deficiency?

Blood clots can cause death. Blood clots in the lungs are very dangerous.

When should I contact a medical professional for Congenital Antithrombin 3 Deficiency?

See your provider if you have symptoms of this condition.

How do I prevent Congenital Antithrombin 3 Deficiency?

Once a person is diagnosed with antithrombin III deficiency, all close family members should be screened for this disorder. Blood thinning drugs can prevent blood clots from forming and prevent complications from clotting.



Anderson JA, Hogg KE, Weitz JI. Hypercoagulable states. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier Saunders; 2018:chap 140.

Schafer AI. Thrombotic disorders: hypercoagulable states. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 176.

  • Condition: Massive Sinus Thrombosis and Antithrombin III Deficiency
  • Journal: Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis
  • Treatment Used: Mechanical Thrombectomy
  • Number of Patients: 1
  • Published —
This case report describes a patient that developed a massive sinus thrombosis from an antithrombin III deficiency that was treated using mechanical thrombectomy.
  • Condition: Hereditary antithrombin (AT) in pregnancy
  • Journal: Taiwanese journal of obstetrics & gynecology
  • Treatment Used: Recombinant human antithrombin (rhAT
  • Number of Patients: 1
  • Published —
This study reported the first use of recombinant human antithrombin (rhAT) to prevent venous thromboembolism in a 30 year old Japanese pregnant woman with hereditary antithrombin (AT).