Alexandra Howson, PhD
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.
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. 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:
In addition, if the liver is affected in adults, the following symptoms may be present:
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:
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:
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
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.
If you smoke, your doctor will work with you to help you stop. Smoking can increase the damage to your lungs.
There is no specific treatment for liver disease due to AAT deficiency. Treatment focuses on symptoms and preventing complications. Treatment may include:
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.
American Lung Foundation
Canadian Liver Foundation
Canadian Thoracic Society
DynaMed Editors. Alpha-1 anti-trypsin deficiency (AAT). EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed/what.php. Updated June 2, 2010. Accessed June 7, 2010.
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Mo Med. 2007; 104(3): 255-259.
The Merck Manuals Online Library. Alpha-1 antitrypsin deficiency. The Merck Manuals Online Library website. Available at:
http://www.merck.com/mmpe/sec05/ch049/ch049b.html?qt=alpha%201%20antitrypsin%20deficiency&alt=sh. Accessed June 7, 2010.
National Jewish Health. Alpha-1 antitrypsin deficiency: inherited liver disease. National Jewish Health website. Available at:
http://www.nationaljewish.org/healthinfo/conditions/alpha-1/inherited-liver-disease/index.aspx. Accessed June 8, 2010.
Wood D. Emphysema. EBSCO Health Library website. Available at:
http://www.ebscohost.com/healthLibrary/. Updated May 24, 2010. Accessed June 7, 2010.
Last reviewed June 2013 by
Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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