Alpha-1 antitrypsin (AAT) deficiency is a condition in which the body does not make enough of AAT, a protein that protects the lungs and liver from damage. The condition can lead to COPD and liver disease (cirrhosis).
AAT deficiency; Alpha-1 protease deficiency; COPD - alpha-1 antitrypsin deficiency; Cirrhosis - alpha-1 antitrypsin deficiency
AAT is a type of protein called a protease inhibitor. AAT is made in the liver and it works to protect the lungs and liver.
AAT deficiency means there is not enough of this protein in the body. It is caused by a genetic defect. The condition is most common among Europeans and North Americans of European descent.
Adults with severe AAT deficiency will develop emphysema, often before 40 years of age. Smoking can increase the risk of emphysema.
Symptoms may include any of the following:
- Shortness of breath with and without exertion, and other symptoms of COPD
- Symptoms of liver failure
- Loss of weight without trying
Exams and Tests
A physical examination may reveal a barrel-shaped chest, wheezing, or decreased breath sounds. The following tests may also help with diagnosis:
- AAT blood test
- Arterial blood gases
- Chest x-ray
- CT scan of the chest
- Genetic testing
- Lung function test
Your health care provider may suspect you of having this condition if you develop:
- COPD before age 45
- COPD but you have never smoked or been exposed to toxins
- COPD and you have a family history of the condition
- Cirrhosis and no other cause can be found
- Cirrhosis and you have a family history of liver disease
Treatment for AAT deficiency involves replacing the missing AAT protein. The protein is given through a vein each week or every 4 weeks. This is only slightly effective at preventing more lung damage in people without end-stage disease. This procedure is called augmentation therapy.
If you smoke, you need to quit.
Other treatments are also used for COPD and cirrhosis.
Some people with this deficiency will not develop liver or lung disease.
COPD and cirrhosis can be life threatening.
Complications of AAT deficiency include:
- Bronchiectasis (damage of the large airways)
- Chronic obstructive pulmonary disease (COPD)
- Liver failure or cancer
When to Contact a Medical Professional
Call your provider if you develop symptoms of AAT deficiency.
Han MK, Lazarus SC. COPD: clinical diagnosis and management. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 44.
Hatipoglu U, Stoller JK. a1-antitrypsin deficiency. Clin Chest Med. 2016;37(3):487-504. PMID: 27514595 www.ncbi.nlm.nih.gov/pubmed/27514595.
Winnie GB, Boas SR. a1-antitrypsin deficiency and emphysema. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 393.
- Last reviewed on 7/28/2018
- Denis Hadjiliadis, MD, MHS, Paul F. Harron, Jr. Associate Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician 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. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.