Alpha 1 Anti-Trypsin Deficiency

(AAT Deficiency; Alpha-1 Antiprotease Deficiency)

Pronounced: Al-fa-wun An-tee-TRIP-sin Dee-FISH-en-see



Alpha 1 anti-trypsin (AAT) deficiency is a rare genetic disorder that causes the enzyme AAT to not work well. It can cause lung and liver disease in children and adults.



AAT deficiency is an inherited disorder. It is passed from parents to children. This condition occurs when the liver does not make useful AAT. AAT is a protein that protects the lungs and other organs from damage. When functional AAT levels are too low, lung damage may occur.

People with AAT deficiency can also develop liver disease. AAT deficiency is one of the major causes of genetic liver disease in children. The liver makes an abnormal version of AAT protein that builds up in the liver. This blockage can damage liver cells. In some cases, severe liver damage can occur.

Risk Factors

Risk Factors

If either of your parents have the gene for AAT deficiency, you are at risk of developing problems due to the disease. If both your parents carry the gene, you are at higher risk of having severe problems.



The first symptoms of the disease often appear in adulthood between the ages of 20-50 years:

  • 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—panniculitis

In addition, if the liver is affected in adults, the following symptoms may be present:

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

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

  • Infants:

  • Older children:

    • Fatigue
    • Poor appetite
    • Swollen abdomen



Your doctor will ask about your symptoms and medical history and do a physical exam. Your doctor may refer you to a doctor who specializes in the lungs or liver, depending on the symptoms you are having.

Tests may include the following:

  • Blood tests—to examine if AAT levels in the blood are low
  • Chest x-ray—to evaluate the lungs
  • Genetic testing—to identify the inherited change that causes AAT
  • Liver biopsy —a small piece of the liver is removed and examined for inflammation or scarring

Liver Biopsy

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Talk with your doctor about the best treatment plan for you. Treatment options include the following:

Treatment for Lung Disease


Your doctor may prescribe medications to boost the levels of AAT. These may be given weekly through an IV in your arm. If you have emphysema, your doctor may treat you with inhaled steroids and other medications to improve your breathing.

Smoking Cessation

If you smoke, your doctor will work with you to help you stop. Smoking can increase the damage to your lungs.

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 reduce your chance of emphysema:

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


Alpha-1 Association

American Lung Association


Canadian Liver Foundation

The Lung Association


Alpha-1 antitrypsin deficiency. National Jewish Health website. Available at:
Accessed February 9, 2015.

Alpha-1 antitrypsin deficiency. The Merck Manual Professional Edition website. Available at:
Accessed June 2014. Accessed February 9, 2015.

Alpha-1 anti-trypsin deficiency (AAT). EBSCO DynaMed website. Available at:
Updated June 13, 2014. Accessed February 9, 2015.

COPD. EBSCO DynaMed website. Available at:
Updated January 15, 2015. Accessed February 9, 2015.

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

Last reviewed February 2015 by Michael Woods, MD
Last Updated: 6/20/2013

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