Alpha-1 antitrypsin (AAT) deficiency

What is alpha-1 antitrypsin deficiency?

Alpha-1 antitrypsin (AAT) deficiency

Alpha-1 antitrypsin (AAT) deficiency is a condition that raises your risk for lung and other diseases.

AAT is a protein made in your liver to help protect the lungs. If your body does not make enough AAT, your lungs are more easily damaged from smoking, pollution, or dust from the environment. This can lead to COPD. AAT deficiency may also cause a liver disease called cirrhosis. This is more common in children who have AAT deficiency.

AAT deficiency runs in families. Many people do not know that they have it, but early diagnosis can help prevent COPD and other serious lung diseases. Talk to your doctor if you have a family member who has AAT deficiency or who was diagnosed with COPD in their 40s or 50s. Also, talk to your doctor if you have symptoms such as an ongoing cough, shortness of breath, wheezing, or liver disease.


How do you get it?

Because AAT deficiency is an inherited disease, meaning it runs in families, it cannot be prevented. It can happen to anyone of any race or ethnicity. However, it is more common in white people of Northern-European backgrounds.

Everyone inherits two AAT genes, one gene from each parent. If you inherit a mutated, or changed gene from each parent, you will have AAT deficiency.

If you inherit a mutated AAT gene from one parent and a normal AAT gene from the other parent, you are a carrier for the condition. You might have lower levels of AAT protein in your blood, but you most likely will not have AAT deficiency. You might also pass the mutated gene to your children.

AAT deficiency is a complex disease, and many factors, some known, like smoking, and others still unknown, contribute to how it impacts different people. Sometimes, even if you inherit two mutated AAT genes, you may not have any symptoms or health problems. You may never even realize that you have AAT deficiency.

What are the symptoms?

Some people do not have any symptoms. For those who do, symptoms usually appear in people between 20 and 50 years old.

Often, people are diagnosed with asthma first. This is because wheezing is also a symptom of asthma. Also, people who have AAT deficiency respond well to asthma medicines. Some people can develop symptoms of COPD.

Some people who have AAT deficiency may have liver damage. Signs of liver damage include jaundice and swelling in your legs. Rarely, AAT deficiency can cause skin problems, such as painful lumps or patches.

How is it diagnosed?

Your doctor may test you for AAT deficiency if you have relatives who have AAT deficiency or a lung or liver disease or after you develop a lung or liver disease that is related to the condition.

  • A blood test can check the level of AAT protein in your blood. If the level is lower than normal, it is likely that you have AAT deficiency.
  • A genetic test is the most certain way to check for AAT deficiency and should be done to confirm the results of the blood test and find the mutation in the AAT gene. A genetic counselor can help you understand what to expect from a genetic test and what your results mean.
  • A pulmonary test to see how well your lungs are working may be recommended by your doctor if you have COPD related to AAT deficiency.

How is it treated?

There is no cure for AAT deficiency, but there are treatments to slow the lung damage it causes.


You may need a lifelong treatment called augmentation therapy. This treatment raises the levels of the AAT protein in your lungs, using ATT protein taken from the blood of donors. This helps slow down lung damage. Side effects of this treatment are rare and may include a mild fever, headaches, nausea, and dizziness.

If you have COPD, you may also need medicines or other treatments. Talk to your doctor about ways to help prevent or delay lung damage, such as quitting smoking and avoiding secondhand smoke, dust, or air pollution.



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