Key Points about Alpha-1 Antitrypsin (AAT) Deficiency

  • Alpha-1 antitrypsin (AAT) deficiency is caused by a gene mutation and is most common in those of European ancestry.
  • Smoking increases your risk of developing AAT deficiency.
  • Treatment for AAT deficiency is called augmentation therapy and involves receiving regular AAT supplementation through a vein.


In alpha-1 antitrypsin (AAT) deficiency, the body doesn’t make enough of the protein that protects the lungs and liver from damage, which is known as AAT. If not properly diagnosed and treated, AAT deficiency may lead to chronic obstructive pulmonary disease (COPD), emphysema or cirrhosis of the liver. 

AAT deficiency causes 

A genetic defect causes AAT deficiency. 

AAT deficiency risk factors

Factors that put you at an increased risk for developing AAT deficiency include:

  • Being European or of European descent
  • Smoking or working in poorly ventilated areas with smoke, dust or fumes can play a part in developing more advanced lung diseases. 

AAT deficiency symptoms

Signs and symptoms of this condition can include:

  • Liver failure
  • Shortness of breath (with and without physical activity)
  • Unintentional weight loss
  • Wheezing

AAT deficiency diagnosis

Your specialist will use one or more of the following diagnostic tools to diagnose AAT:

  • Physical exam - your specialist will complete a physical exam and ask you about your symptoms and history related to AAT deficiency. In the physical exam, your doctor will check for signs of this disorder, including a barrel-shaped chest, decreased breath sounds or wheezing.
  • Blood tests - your specialist will obtain a sample of your blood for close analysis in the lab. If your blood contains decreased levels of AAT, you may have AAT deficiency. Blood tests may also measure your blood gases, which show how much oxygen and carbon dioxide are in your blood. If these levels are out of normal ranges, you may have AAT deficiency that has damaged your lungs and their function.
  • Genetic testing - because a gene mutation causes AAT deficiency, genetic testing can reveal if you are a carrier for the specific gene.
  • Imaging tests - your specialist may order imaging tests – such as a chest X-ray or computed tomography (CT) scan of the chest – to see if the AAT deficiency has lead to lung damage.
  • Lung function test - your specialist may order a lung function test – or pulmonary function test – to determine how well your lungs are working. In this test, a specialized instrument called a spirometer measures how much air you exhale (breathe out), how quickly you exhale, how much air you inhale (breathe in) and how quickly you inhale. Your specialist uses these measurements to determine how well your lungs are functioning and whether they have been damaged due to AAT deficiency.

AAT deficiency treatment

Treatment for AAT deficiency focuses on replacing the AAT protein that is missing from your body. This treatment is called augmentation therapy. You will receive AAT through a vein once per week, or every four weeks. Your specialist will determine the best treatment schedule for you based on a variety of factors. 

When should I seek care?

If you experience any of these symptoms, start by voicing your concerns and symptoms to your primary care provider. From there, your doctor may suggest seeing a liver specialist for more specialized treatment.

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