Skip to Content

Alpha-1 antitrypsin deficiency

Definition

Alpha-1 antitrypsin (AAT) deficiency is condition passed down through families in which the liver does not make enough of a protein that protects the lungs and liver from damage. The condition can lead to emphysema and liver disease.

Alternative Names

AAT deficiency

Causes

Alpha-1 antitrypsin (AAT) is a type of protein called a "protease inhibitor." AAT normally works to protect the lungs from a naturally occuring destructive enzyme that is produced by the lungs in response to infections and toxins (such as cigarette smoke). Without enough AAT, these enzymes slowly destroy the lung tissue.

AAT deficiency is caused by a genetic defect that results in not enough AAT in the liver, lungs, and blood. Persons with this deficiency may also develop liver disease.

Studies show that AAT deficiency may be more common than once thought. Most adults with severe deficiency will develop emphysema, which often begins before age 40. Smoking can increase your risk. The condition is most common among Europeans and North Americans of European descent.

Symptoms

Exams and Tests

A physical examination may reveal a barrel-shaped chest. Listening to the chest with a stethoscope may reveal wheezing or decreased breath sounds. The following tests may also help with diagnosis:

Your doctor may suspected you having this condition if you develop:

  • Emphysema before age 45
  • Emphysema but have never smoked or been exposed to toxins
  • Liver disease or hepatitis and no other cause can be found

Treatment

Treatment involves replacing the missing AAT protein. The protein is given through a vein each week. However, it is not yet known who may benefit from such therapy.

Quitting smoking is crucial.

Other treatments specifically for emphysema and cirrhosis are also used.

Outlook (Prognosis)

Some people with this deficiency will not develop liver or lung disease. However, emphysema and cirrhosis can be deadly.

Possible Complications

  • Cirrhosis or liver failure
  • Emphysema
  • Liver cancer

When to Contact a Medical Professional

Call your health care provider if you develop symptoms of AAT deficiency.

References

Köhnlein T, Welte T. Alpha-1 antitrypsin deficiency: pathogenesis, clinical presentation, diagnosis, and treatment. Am J Med. 2008;121(1):3-9.

Stoller JK, Tomashefski J, Crystal RG, et al. Mortality in individuals with severe deficiency of alpha-1-antitrypsin: Findings from the National Heart, Lung, and Blood Institute Registry. Chest. April 2005;127:1196-1204.

Review Date: 8/29/2008
Reviewed By: Sean O. Stitham, MD, private practice in Internal Medicine, Seattle, WA; Benjamin Medoff, MD, Assistant Professor of Medicine, Harvard Medical School, Pulmonary and Critical Care Unit, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
adam.com

Disclaimer: The information contained in this website, and its associated websites, is provided as a benefit to the local community, and the Internet community in general; it does not constitute medical advice. We try to provide quality information, but we make no claims, promises or guarantees about the accuracy, completeness, or adequacy of the information contained in or linked to this website and its associated sites. As medical advice must be tailored to the specific circumstances of each patient and healthcare is constantly changing, nothing provided herein should be used as a substitute for the advice of a competent physician. Furthermore, in providing this service, Adventist HealthCare does not condone or support all of the content covered in this site. As an Adventist health care organization, Adventist HealthCare acts in accordance with the ethical and religious directives for Adventist health care services.

Adventist HealthCare · 301-315-3030 · 1801 Research BLVD, Suite 400, Rockville, MD 20850

Submit an Online Information Request