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Alpha 1 Anti-Trypsin Deficiency

(AAT Deficiency; Alpha-1 Antiprotease Deficiency)
  • Definition

    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.
  • Causes

    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.
  • Symptoms

    The first symptoms of the disease often appear in adulthood between the ages of 20-50 years. If you have any of these symptoms, do not assume it is due to AAT deficiency. These symptoms may be caused by other conditions. Tell the doctor if you have any of these:
    • Shortness of breath during mild activity
    • Coughing up sputum (mucus from deep in the lungs)
    • Wheezing
    • Weight loss
    • Emphysema (a lung disease caused by damage to the air sacs)
    • Panniculitis (raised red spots on the skin)
    In addition, if the liver is affected in adults, the following symptoms may be present:
    • Itching
    • Jaundice (yellowing skin and/or whites of eyes)
    • Vomiting
    • Swollen abdomen
    • Abdominal pain
    Symptoms in children can occur in the first weeks of life or later in childhood. If your child has any of these symptoms, do not assume it is due to AAT deficiency. These symptoms may be caused by other conditions. Tell the doctor if your child has any of these:
    • Infants:
    • Older children:
      • Fatigue
      • Poor appetite
      • Swollen abdomen
  • Diagnosis

    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 —a test that uses radiation to take pictures of 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
    Placement of Liver Biopsy Needle
    Copyright © Nucleus Medical Media, Inc.
  • Treatment

    Talk with your doctor about the best treatment plan for you. Treatment options include the following:
    Treatment for Lung Disease
    Your doctor may prescribe medicines to boost the levels of AAT. These may be given weekly through an IV (needle) in your arm. If you have emphysema, your doctor may treat you with inhaled steroids and other medicines 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 (eg, E , D , and K )
    • Medicines to reduce itching and jaundice
    • Liver transplant (in rare cases)
  • Prevention

    You cannot prevent AAT deficiency if you have inherited the condition. But there are steps you can take if you have AAT deficiency to reduce your chance of developing 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 Foundation


    Canadian Liver Foundation

    Canadian Thoracic Society


    DynaMed Editors. Alpha-1 anti-trypsin deficiency (AAT). EBSCO DynaMed website. Available at: Updated June 2, 2010. Accessed June 7, 2010.

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

    The Merck Manuals Online Library. Alpha-1 antitrypsin deficiency. The Merck Manuals Online Library website. Available at: Accessed June 7, 2010.

    National Jewish Health. Alpha-1 antitrypsin deficiency: inherited liver disease. National Jewish Health website. Available at: Accessed June 8, 2010.

    Wood D. Emphysema. EBSCO Health Library website. Available at: Updated May 24, 2010. Accessed June 7, 2010.

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