About Hereditary Antithrombin Deficiency — Overview
Up to an Estimated 150,000 People Have Hereditary Antithrombin (AT) Deficiency
The prevalence of hereditary AT deficiency is estimated to be 1 per 2,000 to 5,000 people in the general
population.1 In the US, the affected population is estimated between 60,000 and 150,000. Assuming there
are 60,000 AT-deficient people in the US, that is at least three times as many as those who have hemophilia A.2
Hereditary antithrombin deficiency is autosomal dominant.1 It takes only one parent to pass the defect on to a child.
| |
• |
Each child of a parent with an antithrombin deficiency gene has a 50% chance of inheriting it |
| |
• |
Homozygous type I mutations have not been found, presumably because they are lethal in utero3 |
More Serious Than Other Thrombophilias4
Because antithrombin is the most important serine protease inhibitor of coagulation,5 hereditary AT
deficiency poses the highest risk of thrombosis of all inherited thrombophilias.4,5
Hereditary Thrombophilias: Comparative Risk of Thrombosis4*
Types and Subtypes
There are 2 primary types of hereditary antithrombin deficiency6:
| |
• |
Type I, in which patients do not produce enough antithrombin |
| |
|
|
– |
A 40% to 60% reduction in AT is associated with an increased risk of spontaneous episodes of thrombosis and pulmonary embolism1 |
| |
• |
Type II, in which the antithrombin produced is defective in a way that affects its function either seriously or sub-clinically4,6 |
| |
|
|
– |
IIa: defects in the reactive thrombin binding site. High risk of thrombosis |
| |
|
|
– |
IIb: defects in the heparin binding site. Low risk of thrombosis |
| |
|
|
– |
IIc: multiple defects. High risk of thrombosis |
Type II is more common than type I.7
References:
| 1. |
|
Thrombate III [prescribing information]. Research Triangle Park, NC; Talecris Biotherapeutics, Inc.; 2006.
|
| 2. |
|
National Heart Lung and Blood Institute. Hemophilia: what is hemophilia? Available at: http://www.nhlbi.nih.gov/health/dci/
Diseases/hemophilia/hemophilia_what.html. Accessed April 30, 2007.
|
| 3. |
|
McKenna R. Antithrombin deficiency. eMedicine from WebMD. Available at: http://www.emedicine.com/
med/topic150.htm. Accessed May 14, 2007.
|
| 4. |
|
Franchini M, Veneri D, Salvagno GL, Manzato F, Lippi G. Inherited thrombophilia. Crit Rev Clin Lab. 2006;43:249-290.
|
| 5. |
|
Perry DJ. Antithrombin and its inherited deficiencies. Blood Rev. 1994;8:37-55.
|
| 6. |
|
Kottke-Marchant K, Duncan A. Antithrombin deficiency: issues in laboratory diagnosis. Arch Pathol Lab Med. 2002;126:1326-1336.
|
| 7. |
|
Tait RC, Walker ID, Perry DJ, et al. Prevalence of antithrombin deficiency in the healthy population. Br J Haematol. 1994;87:106-112.
|
Important Safety Information
Thrombate III therapy has demonstrated a low occurrence of side effects. In clinical studies with Thrombate III, the most common side effects were dizziness, chest tightness, nausea, and a foul taste in the mouth. As with all plasma-derived therapeutics, the potential to transmit infectious agents, such as viruses, cannot be totally eliminated. Individuals who receive infusions of blood or blood plasma may develop signs and/or symptoms of some viral infections, particularly hepatitis C.
Please see full Prescribing Information for Thrombate III.
|