For more information, visit http://www.nhlbi.nih.gov/health/health-topics/topics/aat/

What Is Alpha-1 Antitrypsin Deficiency?

Alpha-1 antitrypsin (an-tee-TRIP-sin) deficiency, or AAT deficiency, is a condition that raises your risk for lung disease (especially if you smoke) and other diseases.

Some people who have severe AAT deficiency develop emphysema (em-fi-SE-ma)—often when they're only in their forties or fifties. Emphysema is a serious lung disease in which damage to the airways makes it hard to breathe.

A small number of people who have AAT deficiency develop cirrhosis (sir-RO-sis) and other serious liver diseases.

Cirrhosis is a disease in which the liver becomes scarred. The scarring prevents the organ from working well. In people who have AAT deficiency, cirrhosis and other liver diseases usually occur in infancy and early childhood.

A very small number of people who have AAT deficiency have a rare skin disease called necrotizing panniculitis (pa-NIK-yu-LI-tis). This disease can cause painful lumps under or on the surface of the skin.

This article focuses on AAT deficiency as it relates to lung disease.

Overview

Alpha-1 antitrypsin, also called AAT, is a protein made in the liver. 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.

AAT deficiency occurs if the AAT proteins made in the liver aren't the right shape. They get stuck inside liver cells and can't get into the bloodstream.

As a result, not enough AAT proteins travel to the lungs to protect them. This increases the risk of lung disease. Also, because too many AAT proteins are stuck in the liver, liver disease can develop.

Severe AAT deficiency occurs if blood levels of the AAT protein fall below the lowest amount needed to protect the lungs.

AAT deficiency is an inherited condition. "Inherited" means it's passed from parents to children through genes.

Doctors don't know how many people have AAT deficiency. Many people who have the condition may not know they have it. Estimates of how many people have AAT deficiency range from about 1 in every 1,600 people to about 1 in every 5,000 people.

Outlook

People who have AAT deficiency may not have serious complications, and they may live close to a normal lifespan.

Among people with AAT deficiency who have a related lung or liver disease, about 3 percent die each year.

Smoking is the leading risk factor for life-threatening lung disease if you have AAT deficiency. Smoking or exposure to tobacco smoke increases the risk of earlier lung-related symptoms and lung damage. If you have severe AAT deficiency, smoking can shorten your life by as much as 20 years.

AAT deficiency has no cure, but treatments are available. Treatments often are based on the type of disease you develop.

What Causes Alpha-1 Antitrypsin Deficiency?

Alpha-1 antitrypsin (AAT) deficiency is an inherited disease. "Inherited" means it's passed from parents to children through genes.

Children who have AAT deficiency inherit two faulty AAT genes, one from each parent. These genes tell cells in the body how to make AAT proteins.

In AAT deficiency, the AAT proteins made in the liver aren't the right shape. Thus, they get stuck in the liver cells. The proteins can't get to the organs in the body that they protect, such as the lungs. Without the AAT proteins protecting the organs, diseases can develop.

The most common faulty gene that can cause AAT deficiency is called PiZ. If you inherit two PiZ genes (one from each parent), you'll have AAT deficiency.

If you inherit a PiZ gene from one parent and a normal AAT gene from the other parent, you won't have AAT deficiency. However, you might pass the PiZ gene to your children.

Even if you inherit two faulty AAT genes, you may not have any related complications. You may never even realize that you have AAT deficiency.

Who Is at Risk for Alpha-1 Antitrypsin Deficiency?

Alpha-1 antitrypsin (AAT) deficiency occurs in all ethnic groups. However, the condition occurs most often in White people of European descent.

AAT deficiency is an inherited condition. "Inherited" means the condition is passed from parents to children through genes.

If you have bloodline relatives with known AAT deficiency, you're at increased risk for the condition. Even so, it doesn't mean that you'll develop one of the diseases related to the condition.

Some risk factors make it more likely that you'll develop lung disease if you have AAT deficiency. Smoking is the leading risk factor for serious lung disease if you have AAT deficiency. Your risk for lung disease also may go up if you're exposed to dust, fumes, or other toxic substances.

What Are the Signs and Symptoms of Alpha-1 Antitrypsin Deficiency?

The first lung-related symptoms of alpha-1 antitrypsin (AAT) deficiency may include shortness of breath, less ability to be physically active, and wheezing. These signs and symptoms most often begin between the ages of 20 and 40.

Other signs and symptoms may include repeated lung infections, tiredness, a rapid heartbeat upon standing, vision problems, and weight loss.

Some people who have severe AAT deficiency develop emphysema (em-fi-SE-ma)—often when they're only in their forties or fifties. Signs and symptoms of emphysema include problems breathing, wheezing, and a chronic (ongoing) cough.

At first, many people who have AAT deficiency are diagnosed with asthma. This is because wheezing also is a symptom of asthma. Also, people who have AAT deficiency respond well to asthma medicines.

How Is Alpha-1 Antitrypsin Deficiency Diagnosed?

Alpha-1 antitrypsin (AAT) deficiency usually is diagnosed after you develop a lung or liver disease that's related to the condition.

Your doctor may suspect AAT deficiency if you have signs or symptoms of a serious lung condition, especially emphysema, without any obvious cause. He or she also may suspect AAT deficiency if you develop emphysema when you're 45 years old or younger.

Specialists Involved

Many doctors may be involved in the diagnosis of AAT deficiency. These include primary care doctors, pulmonologists (lung specialists), and hepatologists (liver specialists).

To diagnose AAT deficiency, your doctor will:

Ask about possible risk factors. Risk factors include smoking and exposure to dust, fumes, and other toxic substances.
Ask about your medical history. A common sign of AAT deficiency is if you have a lung or liver disease without any obvious causes or risk factors. Another sign is if you have emphysema at an unusually early age (45 years or younger).
Ask about your family's medical history. If you have bloodline relatives who have AAT deficiency, you're more likely to have the condition.

Diagnostic Tests

Your doctor may recommend tests to confirm a diagnosis of AAT deficiency. He or she also may recommend tests to check for lung- or liver-related conditions.

A genetic test is the most certain way to check for AAT deficiency. This test will show whether you have faulty AAT genes.

A blood test also may be used. This test checks the level of AAT protein in your blood. If the level is a lot lower than normal, it's likely that you have AAT deficiency.

Lung-Related Tests

If you have a lung disease related to AAT deficiency, your doctor may recommend lung function tests and high-resolution computed tomography (to-MOG-rah-fee) scanning, also called CT scanning.

Lung function tests measure how much air you can breathe in and out, how fast you can breathe air out, and how well your lungs deliver oxygen to your blood. These tests may show how severe your lung disease is and how well treatment is working.

High-resolution CT scanning uses x rays to create detailed pictures of parts of the body. A CT scan can show whether you have emphysema or another lung disease and how severe it is.

How Is Alpha-1 Antitrypsin Deficiency Treated?

Alpha-1 antitrypsin (AAT) deficiency has no cure, but its related lung diseases have many treatments. Most of these treatments are the same as the ones used for a lung disease called COPD (chronic obstructive pulmonary disease).

If you have symptoms related to AAT deficiency, your doctor may recommend:

Medicines called inhaled bronchodilators (brong-ko-di-LA-tors) and inhaled steroids. These medicines help open your airways and make breathing easier. They also are used to treat asthma and COPD.
Flu and pneumococcal (noo-mo-KOK-al) vaccines to protect you from illnesses that could make your condition worse. Prompt treatment of lung infections also can help protect your lungs.
Pulmonary rehabilitation (rehab). Rehab involves treatment by a team of experts at a special clinic. In rehab, you'll learn how to manage your condition and function at your best.
Extra oxygen, if needed.
A lung transplant. A lung transplant may be an option if you have severe breathing problems. If you have a good chance of surviving the transplant surgery, you may be a candidate for it.

Augmentation (og-men-TA-shun) therapy is a treatment used only for people who have AAT-related lung diseases. This therapy involves getting infusions of the AAT protein. The infusions raise the level of the protein in your blood and lungs.

Not enough research has been done to show how well this therapy works. However, some research suggests that this therapy may slow the development of AAT deficiency in people who don't have severe disease.

People who have AAT deficiency and develop related liver or skin diseases will be referred to doctors who treat those diseases.

Future Treatments

Researchers are working on possible treatments that will target the faulty AAT genes and replace them with healthy genes. These treatments are in the early stages of development.

Researchers also are studying therapies that will help misshapen AAT proteins move from the liver into the bloodstream. They're also studying a type of augmentation therapy in which the AAT protein is inhaled instead of injected into a vein.

If you're interested in new treatments, ask your doctor about ongoing clinical trials for AAT deficiency.

How Can Alpha-1 Antitrypsin Deficiency Be Prevented?

You can't prevent alpha-1 antitrypsin (AAT) deficiency because the condition is inherited (passed from parents to children through genes).

If you inherit two faulty AAT genes, you'll have AAT deficiency. Even so, you may never develop one of the diseases related to the condition.

You can take steps to prevent or delay lung diseases related to AAT deficiency. One important step is to quit smoking. If you don't smoke, don't start.

Talk with your doctor about programs and products that can help you quit smoking. If you have trouble quitting smoking on your own, consider joining a support group. Many hospitals, workplaces, and community groups offer classes to help people quit smoking.

For more information about how to quit smoking, go to the Health Topics Smoking and Your Heart article and the National Heart, Lung, and Blood Institute's "Your Guide to a Healthy Heart." Although these resources focus on heart health, they include basic information about how to quit smoking.

Also, try to avoid secondhand smoke and places with dust, fumes, or other toxic substances that you may inhale.

Check your living and working spaces for things that may irritate your lungs. Examples include flower and tree pollen, ash, allergens, air pollution, wood burning stoves, paint fumes, and fumes from cleaning products and other household items.

If you have a lung disease related to AAT deficiency, ask your doctor whether you might benefit from augmentation therapy. This is a treatment in which you receive infusions of AAT protein.

Augmentation therapy raises the level of AAT protein in your blood and lungs. (For more information, go to "How Is Alpha-1 Antitrypsin Deficiency Treated?")

Living With Alpha-1 Antitrypsin Deficiency

People who have alpha-1 antitrypsin (AAT) deficiency don't always develop serious lung or liver diseases. This means that you can have AAT deficiency and not even know it.

If you already know you have AAT deficiency, you probably also have a related lung or liver disease. Ongoing medical care and lifestyle changes can help you manage your health.

Ongoing Medical Care

If you have AAT deficiency, you'll need ongoing medical care. Talk with your doctor about how often you should schedule medical visits.

Take all of your medicines as prescribed, and follow your treatment plan. Get flu and pneumococcal vaccines to protect you from illnesses that may worsen your condition. If you have a lung infection, get treatment right away.

You also should get treatment right away for any breathing problems. If treatment includes pulmonary rehabilitation, work with your health care team to learn how to manage your condition and function at your best.

Lifestyle Changes

Quit Smoking and Avoid Lung Irritants

If you smoke, quit. If you don't smoke, don't start. Smoking is the leading risk factor for life-threatening lung disease if you have AAT deficiency.

For more information about how to quit smoking, go to the Health Topics Smoking and Your Heart article and the National Heart, Lung, and Blood Institute's (NHLBI's) "Your Guide to a Healthy Heart." Although these resources focus on heart health, they include basic information about how to quit smoking.

Also, try to avoid secondhand smoke and other lung irritants, such as dust, fumes, or toxins. Check your living and working spaces for things that may irritate your lungs. Examples include flower and tree pollen, ash, allergens, air pollution, wood burning stoves, paint fumes, and fumes from cleaning products and other household items.

Because AAT deficiency is inherited, your children may have the condition or carry the gene for it. Advise them to avoid smoking and to stay away from places where they might inhale irritants or toxins.

Follow a Healthy Diet

A healthy diet is an important part of a healthy lifestyle. A healthy diet includes a variety of vegetables and fruits. It also includes whole grains, fat-free or low-fat dairy products, and protein foods, such as lean meats, poultry without skin, seafood, processed soy products, nuts, seeds, beans, and peas.

A healthy diet is low in sodium (salt), added sugars, solid fats, and refined grains. Solid fats are saturated fat and trans fatty acids. Refined grains come from processing whole grains, which results in a loss of nutrients (such as dietary fiber).

For more information about following a healthy diet, go to the NHLBI's "Your Guide to Lowering Your Blood Pressure With DASH" and the U.S. Department of Agriculture's ChooseMyPlate.gov Web site. Both resources provide general information about healthy eating.

Also, talk with your doctor about whether it's safe for you to drink alcohol.

Be Physically Active

Try to do physical activity regularly. Talk with your doctor about how much and what types of activity are safe for you.

For more information about physical activity, go to the U.S. Department of Health and Human Services' "2008 Physical Activity Guidelines for Americans," the Health Topics Physical Activity and Your Heart article, and the NHLBI's "Your Guide to Physical Activity and Your Heart."

These resources provide information about the benefits of physical activity.

Reduce Stress

Learning how to manage stress, relax, and cope with problems can improve your emotional and physical health. Relaxation techniques—such as meditation, yoga, breathing exercises, and muscle relaxation—can help you cope with stress.

Emotional Issues and Support

Living with AAT deficiency may cause fear, anxiety, depression, and stress. Talk about how you feel with your health care team. Talking to a professional counselor also can help. If you're very depressed, your doctor may recommend medicines or other treatments that can improve your quality of life.

Joining a patient support group may help you adjust to living with AAT deficiency. You can see how other people who have the same symptoms have coped with them. Talk with your doctor about local support groups or check with an area medical center.

Support from family and friends also can help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.

Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. Often, these advances depend on the willingness of volunteers to take part in clinical trials.

Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions. For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.

By taking part in a clinical trial, you can gain access to new treatments before they're widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don't directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.

If you volunteer for a clinical trial, the research will be explained to you in detail. You'll learn about treatments and tests you may receive, and the benefits and risks they may pose. You'll also be given a chance to ask questions about the research. This process is called informed consent.

If you agree to take part in the trial, you'll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.

For more information about clinical trials related to alpha-1 antitrypsin deficiency, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:

For more information about clinical trials for children, visit the NHLBI's Children and Clinical Studies Web page.

Links to Other Information About Alpha-1 Antitrypsin Deficiency

NHLBI Resources

Cough (Health Topics)
Lung Transplant (Health Topics)
Oxygen Therapy (Health Topics)
Pulmonary Rehabilitation (Health Topics)

Non-NHLBI Resources

Alpha-1 Antitrypsin Deficiency (MedlinePlus)
Emphysema (MedlinePlus)

Clinical Trials

Children and Clinical Studies
Clinical Trials (Health Topics)
Current Research (ClinicalTrials.gov)
NHLBI Clinical Trials
NIH Clinical Research Trials and You (National Institutes of Health)
ResearchMatch (funded by the National Institutes of Health)