COPD and Genetics

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

Most people with AAT deficiency will get COPD if they smoke. People with AAT can also develop COPD even if they have never smoked at all.

What is AAT deficiency?1

The liver makes a protein called “AAT” that travels through the body in the bloodstream. The AAT protein’s job is to protect organs – especially the lungs – from damage.

People with AAT deficiency are born with livers that produce AAT proteins that are not the right shape to enter the bloodstream and travel to the lungs. This means that their lungs do not have the protection that they need.

AAT deficiency is a “genetic” or “inherited” condition. This means that it is passed down through families from parents to children in a certain gene. To have AAT deficiency, a person has to get that gene from both of their parents.

What are the symptoms of AAT deficiency?1

Symptoms of AAT deficiency usually start when people are between 20 and 40 years of age. The first signs of AAT deficiency are usually:

Other common symptoms of AAT deficiency are:

  • Multiple lung infections
  • Tiredness
  • Fast heartbeat after standing up
  • Problems with vision
  • Weight loss

What is the link between AAT deficiency and COPD?1,2

People with AAT deficiency have a very high risk of lung diseases like emphysema. Most people with COPD have emphysema.

AAT deficiency causes this risk because the person’s body does not have enough AAT proteins to protect the lungs. Without this protection, irritants like cigarette smoke can damage the lungs very badly.

People with AAT deficiency who smoke often get emphysema at a young age – sometimes as early as their thirties. Smoking also causes them to have more severe emphysema symptoms than people without AAT deficiency.

AAT deficiency can also cause people who have never smoked to develop emphysema earlier than average – between the ages of 40 and 60 years old. Many non-smokers are not diagnosed with AAT deficiency until they develop emphysema at an unusually young age. But some people with AAT deficiency never get emphysema, especially if they do not smoke.

Can AAT deficiency be cured or treated?1

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

The most important step is not to smoke, or for smokers to quit. Almost all smokers with AAT deficiency will get emphysema.

Other steps people with AAT deficiency can take to avoid emphysema are:

  • Avoid being around other people who are smoking
  • Avoid lung irritants like dust and fumes
  • Receive regular medical care
  • Eat a healthy diet
  • Stay as active as possible
  • Reduce stress

If a person with AAT does develop emphysema, then he or she will usually receive the standard treatments for COPD, such as:

Some people with AAT deficiency might also be treated with something called “augmentation therapy.” In this kind of treatment, AAT proteins are delivered directly into the patient’s bloodstream to help protect the lungs from more damage. Patients who receive this kind of therapy have IV blood transfusions once a week.

How common is AAT deficiency?2

AAT deficiency is a rare condition that probably affects around 100,000 Americans. Around 2 to 3% of people with emphysema in the United States have AAT deficiency that caused the disease.

Scientists are not sure exactly how many people have AAT deficiency around they world, because many people who have it never know that they do. They think that more than a million people around the world carry the gene that can cause AAT deficiency.

Are there any other genetic causes of COPD?3

There are probably some genetic conditions other than AAT deficiency that can make certain people more likely to get COPD. This is because some people without AAT deficiency also develop COPD even though they have never been exposed to irritants like cigarette smoke or pollution.

Also, scientists do not understand why some smokers are more likely to get COPD than others. Researchers are working to discover whether there are other genetic links that cause people to have a higher risk of COPD.

Written by: Anna Nicholson | Last reviewed: July 2015.
View References
  1. National Heart, Lung and Blood Institute. “What Is Alpha-1 Antitrypsin Deficiency?” Available at: http://www.nhlbi.nih.gov/health/health­topics/topics/aat/ [Accessed 30 November 2014.]
  2. American Lung Association. “Chronic Obstructive Pulmonary Disorder (COPD) Fact Sheet.” May 2014. Available at: http://www.lung.org/lung-disease/copd/resources/facts-figures/COPD-Fact-Sheet.html [Accessed 30 November 2014.]
  3. “Genetics.” In: Gibson GJ et al., eds. The European Lung White Book: Respiratory Health and Disease in Europe: European Respiratory Society; 2013:30-43.