Alpha-1 antitrypsin deficiency
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 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...
Read Article Now Book Mark ArticleCirrhosis
Cirrhosis is scarring of the liver and poor liver function. It is the last stage of chronic liver disease.
Read Article Now Book Mark ArticleCauses
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, 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 examination 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....
Read Article Now Book Mark Article - Arterial blood gases
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.
Read Article Now Book Mark Article - Chest x-ray
Chest x-ray
A chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.
Read Article Now Book Mark Article - CT scan of the chest
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.
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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COPD
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...
Read Article Now Book Mark Article - Liver failure or cancer
When to Contact a Medical Professional
Contact your provider if you develop symptoms of AAT deficiency.
Reviewed By
Denis Hadjiliadis, MD, MHS, Paul F. Harron, Jr. Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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.
Hatipoglu U, Stoller JK. a1 -antitrypsin deficiency. Clin Chest Med. 2016;37(3):487-504. PMID: 27514595 pubmed.ncbi.nlm.nih.gov/27514595/.
Winnie GB, Boas SR. a1 -antitrypsin deficiency and emphysema. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 421.