Q&A

What is the danger of having an antithrombin III deficiency?

What is the danger of having an antithrombin III deficiency?

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.

What does low antithrombin activity mean?

Reduced antithrombin activity and normal levels of antithrombin antigen suggest a type 2 antithrombin deficiency. This means that there is sufficient antithrombin protein, but it is not functioning as it should. In either case, a deficiency increases the affected person’s risk of developing an inappropriate blood clot.

Does antithrombin inactivate thrombin?

Antithrombin (antithrombin III) is a plasma protease inhibitor that inactivates thrombin and other activated coagulation factors in the intrinsic and common pathways by binding to the active site of these enzymes.

How does antithrombin deficiency affect the risk of blood clots?

It is not well established whether the degree of AT decrease correlates with the risk of thrombosis, i.e. whether patients with lower values have a higher risk for thrombosis. Inherited AT deficiency increases the risk for blood clots, acquired AT deficiency often does not.

Is there a genetic test for antithrombin deficiency?

There are many different mutations in the antithrombin gene that can lead to inherited AT deficiency. Genetic testing is, therefore, not possible in routine clinical practice. It is reserved for research studies. Patients with inherited AT deficiency typically have levels in the 40% – 60 % range.

Can a person be heterozygous with antithrombin deficiency?

It is inherited in a dominant pattern, i.e. there is a 50 % chance that a child will have the disorder if one of the parents has it. Men and women are equally affected. It is independent of blood types. If a person has inherited one defective (mutated) antithrombin gene, he/she is heterozygous.

Is there a cure for congenital antithrombin deficiency?

FDA-approved indication: For replacement therapy in congenital deficiency of AT-III for prevention and treatment of thrombosis and pulmonary emboli. The prognosis depends on the degree of antithrombin deficiency, the nature of the clots formed, and the number of clots formed.