COPD and Genetics

Reviewed by: HU Medical Review Board | Last reviewed: July 2021.

Some people are born with a rare condition called alpha­1 antitrypsin deficiency (AAT deficiency). Having AAT deficiency causes a high risk of getting chronic obstructive pulmonary disease (COPD).1

What is AAT deficiency?

When people have AAT deficiency, their livers do not make enough of an important protein called alpha­1 antitrypsin. This protein protects the body’s tissue from being damaged. In someone with AAT deficiency, there is not enough AAT to protect the lungs, and they can become damaged. AAT deficiency can also cause liver damage.2,3

AAT deficiency is a genetic condition. That means it is passed down through families on a certain gene. You usually need to get 1 mutated AAT gene from each of your parents to have AAT deficiency. If you only have 1 mutated AAT gene, you are considered a carrier. Carriers may have lower levels of AAT but not AAT deficiency. Carriers also risk passing the mutation on to their children.2

What are the symptoms of AAT deficiency?

Some people with AAT deficiency will not show any symptoms. For others, symptoms often start to develop when they are between 20 and 50 years old. Symptoms may include:2,3

  • Shortness of breath
  • Wheezing
  • Persistent cough
  • Difficulty exercising
  • Excessive tiredness
  • Repeated lung infections

These symptoms may be ongoing or become more severe when someone is sick with a respiratory infection like the flu. People with AAT are sometimes first diagnosed with asthma because the symptoms can look similar.2,3

What is the link between AAT deficiency and COPD?

People with AAT deficiency are at a much higher risk of developing lung diseases like emphysema. Emphysema is a disease that is often part of COPD. People with AAT deficiency tend to develop emphysema at a younger age, sometimes in their 30s or 40s.2,3

This risk of developing emphysema or COPD increases even more for people with AAT deficiency if they smoke. Their lungs are much more susceptible to damage from cigarette smoke.2

It is recommended that everyone with COPD is tested for AAT deficiency. Doctors use a simple blood test that checks the level of alpha-1 antitrypsin in the blood. You may also want to get tested if you have a family member with AAT deficiency or a family member diagnosed with COPD before their 60s.3

Can AAT deficiency be cured or treated?

Because AAT deficiency is something a person is born with, it cannot be prevented. It also does not have a cure. However, there are ways for people with AAT deficiency to reduce their risk of getting emphysema or COPD.2,3

Early diagnosis can help people with AAT deficiency avoid risk factors, like smoking. It is important for people with AAT deficiency to avoid smoking themselves and even secondhand smoke. It is also recommended to avoid inhaling irritants like dust, fumes, or other toxins.2,3

Living a healthy lifestyle can reduce the risk of developing emphysema or COPD. Limiting alcohol, maintaining a healthy weight, and regular exercise can all help. Getting flu and pneumonia vaccines can also lower the risk of complications.3

If you have AAT deficiency and have developed COPD, your treatment may include:2,3

  • Oxygen therapy
  • Inhaled steroids
  • COPD drugs
  • Pulmonary rehabilitation, a type of rehab for learning to handle COPD

Non-smokers or people who have quit smoking may be treated with augmentation therapy. This is also sometimes called replacement therapy. In augmentation therapy, people receive infusions of the AAT protein to raise the levels in their blood. Augmentation therapy helps slow down lung damage, but it is not clear if it can reverse existing damage.2,3

Are there any other genetic causes of COPD?

Some studies have shown that close relatives of people with COPD are more likely to develop COPD, even if no one was AAT deficient. This is a sign that other genes may be involved in COPD.1

Scientists have found some specific variations in the DNA sequence, called gene polymorphisms, that may be linked to COPD. They have also found other genetic variations in some proteins that may increase the risk of COPD. However, we do not know yet how these variations have a role in developing COPD. More research is needed to fully understand the impact genetics have on COPD.1

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