• Alpha 1 Anti-Trypsin Deficiency

    (AAT Deficiency; Alpha-1 Antiprotease Deficiency)


    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

    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
    • Raised red spots on the skin
    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
    • Vomiting
    • Swollen abdomen
    • Abdominal pain
    Symptoms in children can occur in the first weeks of life or later in childhood.
      • 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 medical history. A physical exam will be done. You may be referred to a doctor who specializes in the lungs or liver, depending on the symptoms you are having.
    Your bodily fluids and tissues may be tested. This can be done with:
    • Blood tests—to examine if AAT levels in the blood are low
    • 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
    Images may be taken of your lungs. This can be done with a chest x-ray.
    Liver Biopsy
    Placement of Liver Biopsy Needle
    Copyright © Nucleus Medical Media, Inc.


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

    Treatment for Lung Disease

    You may be prescribed 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 on ways to quit. 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 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 9, 2016.

    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 June 2014. Accessed March 9, 2016.

    Alpha-1 anti-trypsin deficiency (AAT). EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T113686/Alpha-1-antitrypsin-AAT-deficiency. Updated August 5, 2015. Accessed March 9, 2016.

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

    Revision Information

    • Reviewer: EBSCO Medical Review BoardMichael Woods, MD
    • Review Date: 03/2017
    • Update Date: 06/20/2013
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