Alpha-1 antitrypsin (A1AT) deficiency is a condition in which the body does not make enough of a protein that protects the lungs and liver from damage. The condition can lead to emphysema and liver disease (cirrhosis).
A1AT is a type of protein called a protease inhibitor. A1AT is made in the liver and it works to protect the lungs and liver.
A1AT 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 A1AT deficiency will develop emphysema, often before 40 years of age. Smoking can increase the risk of emphysema.
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:
Your health care provider may suspect you of having this condition if you develop:
- Emphysema before age 45
- Emphysema but you have never smoked or been exposed to toxins
- Emphysema 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 A1AT deficiency involves replacing the missing A1AT 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 emphysema and cirrhosis.
Some people with this deficiency will not develop liver or lung disease.
Emphysema and cirrhosis can be life threatening.
When to Contact a Medical Professional
Call your provider if you develop symptoms of A1AT deficiency.
AAT deficiency; Alpha-1 protease deficiency; COPD - alpha-1 antitrypsin deficiency; Cirrhosis - alpha-1 antitrypsin deficiency
Han MK, Lazarus SC. COPD. 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.
Review Date 8/21/2016
Updated by: 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, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.