Alpha-1 antitrypsin deficiency
AAT deficiency; Alpha-1 protease deficiency; COPD - alpha-1 antitrypsin deficiency; Cirrhosis - alpha-1 antitrypsin deficiencyAlpha-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 chronic obstructive pulmonary disease (COPD) and liver disease (cirrhosis).
Chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a common lung disease. Having COPD makes it hard to breathe. There are two main forms of COPD:Chroni...
Cirrhosis
Cirrhosis is scarring of the liver and poor liver function. It is the last stage of chronic liver disease.
Causes
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 variant. The condition is most common among Europeans and North Americans of European descent.
Adults with severe AAT deficiency will develop emphysema, sometimes before 40 years of age. Smoking can increase the risk for emphysema and make it occur earlier.
Symptoms
Symptoms may include any of the following:
- Shortness of breath with and without exertion, and other symptoms of COPD
Shortness of breath
Breathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough air
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- Loss of weight without trying
Loss of weight
Unexplained weight loss is a decrease in body weight, when you did not try to lose the weight on your own. Many people gain and lose weight. Uninten...
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Wheezing
Wheezing is a high-pitched whistling sound during breathing. It occurs when air moves through narrowed breathing tubes in the lungs.
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Exams and Tests
A physical exam may reveal a barrel-shaped chest, wheezing, or decreased breath sounds. The following tests may also help with diagnosis:
- AAT blood test
AAT
Alpha-1 antitrypsin (AAT) is a laboratory test to measure the amount of AAT in your blood. The test is also done to check for abnormal forms of AAT....
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Arterial blood gases
Blood gases are a measurement of how much oxygen and carbon dioxide are in your blood. They also determine the acidity (pH) of your blood.
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Chest x-ray
A chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.
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CT scan of the chest
A chest CT (computed tomography) scan is an imaging method that uses x-rays to create cross-sectional pictures of the chest and upper abdomen....
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- Lung function tests
Lung function tests
Pulmonary function tests are a group of tests that measure breathing and how well the lungs are functioning.
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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
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.
To quit
There are many ways to quit smoking. There are also resources to help you. Family members, friends, and co-workers may be supportive. But to be su...
Other treatments are also used for COPD and cirrhosis.
Lung transplant can be used for severe lung disease, and liver transplant can be used for severe cirrhosis.
Outlook (Prognosis)
Some people with this deficiency will not develop liver or lung disease. If you quit smoking, you can slow the progression of the lung disease.
COPD and cirrhosis can be life threatening.
Possible Complications
Complications of AAT deficiency include:
- Bronchiectasis (damage of the large airways)
Bronchiectasis
Bronchiectasis is a disease in which the large airways in the lungs are damaged. This causes the airways to become permanently wider. Bronchiectasis...
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- Liver failure or cancer
When to Contact a Medical Professional
Contact your provider if you develop symptoms of AAT deficiency.
References
Han MK, Lazarus SC. COPD: diagnosis and management. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 64.
Masson VK, Boas SR. a1 -antitrypsin deficiency and emphysema. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 442.
Tejwani V, Stoller JK. The spectrum of clinical sequelae associated with alpha-1 antitrypsin deficiency. Ther Adv Chronic Dis. 2021;12_suppl. PMID: 34408829 pubmed.ncbi.nlm.nih.gov/34408829/.
Lungs - illustration
The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.
Lungs
illustration
Liver anatomy - illustration
The liver serves a wide variety of body functions, including detoxifying blood and producing bile that aids in digestion.
Liver anatomy
illustration
Lungs - illustration
The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.
Lungs
illustration
Liver anatomy - illustration
The liver serves a wide variety of body functions, including detoxifying blood and producing bile that aids in digestion.
Liver anatomy
illustration
Review Date: 8/19/2024
Reviewed By: Allen J. Blaivas, DO, Division of Pulmonary, Critical Care, and Sleep Medicine, VA New Jersey Health Care System, Clinical Assistant Professor, Rutgers New Jersey Medical School, East Orange, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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