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Alpha-1 antitrypsin deficiency

Alpha-1 antitrypsin (AAT) is a protein made mainly by your liver.

It protects your lungs and other organs from:

  • infections
  • irritants such as cigarette smoke and gases

AAT deficiency is when you have low levels of AAT in your blood. It is a rare genetic (inherited) condition.

It can increase your risk of developing conditions that affect your lungs or your liver. For example, emphysema (damaged air sacs in the lungs) or cirrhosis (scarring of the liver).

AAT deficiency can cause lung problems in adults and liver problems in both adults and children. Some of these conditions can be life-threatening.

In Ireland, 1 in 25 people has the gene that causes AAT deficiency.

Symptoms of AAT deficiency

People with AAT deficiency may not develop any health issues or have any symptoms. You might never know you have AAT deficiency.

People who have lung problems caused by AAT deficiency may notice symptoms in their 30s or 40s. But lung problems can also happen later in life. Smokers usually see symptoms at a younger age.

The symptoms of lung disease caused by AAT deficiency are like those of chronic obstructive pulmonary disease (COPD).

Symptoms may include:

Symptoms may increase when you have a cold or flu.

If the liver is affected by AAT deficiency, symptoms may include:

  • tiredness
  • loss of appetite
  • weight loss
  • swelling of the feet or tummy
  • yellowing of the skin (jaundice) or the white part of the eyes
  • vomiting blood
  • blood in your poo

Talk to your GP if you have these symptoms.

Diagnosing AAT deficiency

AAT deficiency is a genetic condition. Several members of a family may be affected.

Many people do not know that they have it. Early diagnosis can help prevent you from developing a serious lung or liver condition.

Treatment for AAT deficiency

AAT deficiency has no cure, but there are new treatments being developed.

If you smoke, you should quit or get help to quit smoking. You should also avoid secondhand smoke and other harmful fumes.

If you have complications from AAT deficiency, you may also need:

Living with AAT deficiency

If you have AAT deficiency, you may have a related condition that affects your lungs or your liver. Ongoing medical care and lifestyle changes can help you manage your health and reduce the risk of health problems.

Regular follow-up care is important.

You will need to:

  • have regular pulmonary (lung) function tests or imaging tests to monitor your condition
  • get the flu and pneumococcal vaccines to protect you from illnesses that may worsen your condition
  • take all your medicines as prescribed and follow your treatment plan

If you have a lung infection or any breathing problems you will need immediate treatment.

If you have AAT deficiency, you can ask your GP to refer you to the National Centre of Expertise for AAT Deficiency at Beaumont Hospital.

More support

You can find more information and supports for living with AAT at Alpha-1 Foundation Ireland.

Page last reviewed: 29 January 2026
Next review due: 29 January 2029