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 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:
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:
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:
Call your provider if you develop symptoms of AAT deficiency.
Reviewed 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, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.