Passer au contenu principal

Alpha1 antitrypsin (AAT) deficiency is rare genetic (inherited) condition that may result in serious lung disease in adults and/or liver disease at any age.

Alpha 1 is a plasma protein produced in the liver, which inhibits the activity of trypsin and other proteolytic enzymes. Alpha-1 occurs when there is a lack of this protein. AAT main function  is to protect the lungs from inflammation caused by infection and inhaled irritants such as tobacco smoke.

Blood and tissues have a protease inhibitor that binds the enzyme to prevent unrestricted and potentially harmful protease activity. The commonest protease inhibitor in the blood is alpha-1 antitrypsin and its role is to protect the tissues from protease attack. Normally, the protein travels through the bloodstream. It helps protect the body’s organs from the harmful effects of other proteins. The lungs are one of the main organs that the AAT protein protects from attacks of foreign substances within the body and may be harmful.

Symptoms of ATT:

  •  Shortness of breath
  • Wheezing
  • Coughing with or without sputum (phlegm) production
  • Recurring respiratory infections
  • Rapid deterioration of lung function
  • Unexplained liver problems and /or elevated liver enzymes

This shortness of breath initially occurs only on exertion but can lead to difficulty breathing at rest. This usually occurs over 15 to 20 years, but can lead to respiratory failure and premature death.


AAT deficiency has no cure, but treatments are available. They are often based on the type of disease a patient develops.

People at risk

Alpha-1 antitrypsin deficiency is thought to be one of the commonest genetic deficiencies in Caucasian (or white) populations. Both sexes are at risk.

Alpha-1 antitrypsin deficiency has been found across Europe, but the prevalence and type of the disease varies.

The severe type of alpha-1 antitrypsin deficiency is commonest on the North Western European seaboard including the British Isles. Alpha-1 antitrypsin deficiency occurs in up to 1 in 1600 people in Scandinavia, but is less common elsewhere.

In the lungs, AAT deficiency produces COPD. The disease often becomes noticeable between the ages of 30 to 40 years in smokers and 10 to 15 years later in non-smokers. Over the next 15 to 20 years the lung disease may gradually lead to respiratory failure and death. The progress of liver disease is even less predictable. AAT can produce jaundice and liver problems in babies within days of their birth.

AAT is relatively easy to detect by testing the blood alpha-1 antitrypsin levels.

Liver function should be assessed by examination and blood tests, and further scans may be needed. Lung function can be measured by breathing tests, chest X-rays and CT scans.

Sources of information:


February 28th, 2013 | Published in chonic diseases,