We have changed our visitation policy for the safety of our patients and staff. Click here for the updated visitation policy and click here for information about COVID-19.

Lahey Health is now part of Beth Israel Lahey Health

by Howson A
(AAT Deficiency; Alpha-1 Antiprotease Deficiency)


Alpha 1 anti-trypsin (AAT) deficiency is a rare genetic problem. It causes low levels of the enzyme AAT or stops it from working well. This can lead to lung and liver disease in children and adults.


AAT is a protein that protects the lungs and other organs. It is made in the liver. A damaged gene stops the liver from making useful AAT.

The gene that causes AAT deficiency is passed from parents to children.

AAT deficiency can also harm the liver. The abnormal AAT proteins build up in the liver. It causes blockages which damage the liver tissue.

Risk Factors

A child is at risk of AAT deficiency if either parent has the damaged gene. The risk of severe problems is higher if both parents carry the gene.


The first symptoms of the disease often appear in between the ages of 20 to 50 years. They may include:

  • Shortness of breath during mild activity
  • Coughing up sputum (mucus from deep in the lungs)
  • Wheezing
  • Weight loss
  • Lung disease that affects the air sacs (emphysema)
  • Raised red spots on the skin

If the liver is affected in adults, the following symptoms may be present:

  • Itching
  • Yellowing of the skin and/or whites of the eyes
  • Vomiting
  • Swollen abdomen
  • Abdominal pain

Symptoms in children can occur in the first weeks of life or later in childhood.

  • Infants:
    • Yellowing of the skin and/or whites of the eyes
    • Poor growth and weight gain
    • Foul-smelling stools
    • Swollen abdomen
    • Vomiting
    • Itching
  • Older children:
    • Fatigue
    • Poor appetite
    • Swollen abdomen


You will be asked about your symptoms and past health. A physical exam will be done. You may be referred to a doctor who specializes in the lungs or liver.

Change in AAT or the liver will be found through:

  • Blood tests—can measure AAT levels in the blood
  • Genetic testing—to find genetic change that causes AAT deficiency
  • Liver biopsy—a small piece of the liver is removed and examined

Images may be taken of your lungs. This can be done with a chest x-ray or a CT scan.

Liver Biopsy
Placement of Liver Biopsy Needle
Copyright © Nucleus Medical Media, Inc.


Treatment will help to manage changes to the lung or liver.

Treatment for Lung Disease

Options to ease breathing and decrease complications include:

  • Augmentation therapy—AAT is given through an IV. It may boost levels of AAT.
  • Inhaled bronchodilators and inhaled steroid—to help open airway and ease breathing.
  • Vaccines—flu and pneumococcal vaccines can prevent or decrease severity of lung infections.
  • Oxygen therapy—if oxygen levels in the body are too low.
  • Lung reduction surgery—remove damaged area of lung. It will help the rest of the lung work better.

Smoking can increase the damage to your lungs. Quit smoking and avoid being around others who smoke.

Treatment for Liver Damage

There is no specific treatment for liver disease due to AAT deficiency. Treatment focuses on symptoms and preventing complications. Treatment may include:

  • Vitamin supplements, such as E , D , and K
  • Medications to reduce itching and jaundice
  • Rarely, a liver transplant


You cannot prevent AAT deficiency if you have inherited the condition. If you have AAT deficiency, you can keep your lungs healthier by:

  • Quit smoking.
  • Avoid exposure to secondhand smoke.
  • Avoid exposure to air pollution or irritants.
  • Wear protective mask if exposed to irritants or toxins at work.


Alpha-1 Association  http://www.alpha1.org 

American Lung Association  http://www.lung.org 


Canadian Liver Foundation  http://www.liver.ca 

The Lung Association  http://www.lung.ca 


Alpha-1 antitrypsin deficiency. National Jewish Health website. Available at: http://www.nationaljewish.org/healthinfo/conditions/alpha-1. Accessed March 19, 2018.

Alpha-1 antitrypsin deficiency. The Merck Manual Professional Edition website. Available at: http://www.merckmanuals.com/professional/pulmonary%5Fdisorders/chronic%5Fobstructive%5Fpulmonary%5Fdisease%5Fand%5Frelated%5Fdisorders/alpha-1%5Fantitrypsin%5Fdeficiency.html. Accessed January 2017. Accessed March 19, 2018.

Alpha-1 anti-trypsin deficiency (AAT). EBSCO DynaMed Plus website. Available at:  https://www.dynamed.com/topics/dmp~AN~T113686/Alpha-1-antitrypsin-AAT-deficiency  . Updated January 19, 2018. Accessed March 19, 2018.

Hericks AJ. An overview of alpha-1 antitrypsin deficiency. Mo Med. 2007;104(3): 255-259.

Revision Information

  • Reviewer: EBSCO Medical Review Board Kari Kassir, MD
  • Review Date: 03/2018
  • Update Date: 06/20/2013