Alpha-1 antitrypsin deficiency (AATD) is an inherited condition that can increase the risk of lung and liver disease. It occurs when the body produces insufficient amounts of functional alpha-1 antitrypsin, a protein that helps protect lung tissue from damage caused by enzymes involved in inflammation. The condition can affect people differently. Some individuals have few or no noticeable symptoms, while others develop chronic lung disease, liver problems, or both. Diagnosis may involve blood testing, genetic analysis, protein testing, lung-function assessment, and imaging.
What Is Alpha-1 Antitrypsin?
Alpha-1 antitrypsin is a protein produced mainly by the liver. It travels through the bloodstream and helps protect tissues, particularly the lungs, from an enzyme called neutrophil elastase.
Neutrophil elastase helps fight infections and break down damaged tissue, but excessive activity can damage healthy lung structures. Alpha-1 antitrypsin helps keep this activity under control.
When alpha-1 antitrypsin levels are too low or the protein does not function properly, lung tissue may be more vulnerable to progressive damage.
What Causes Alpha-1 Antitrypsin Deficiency?
AATD is caused by changes in the SERPINA1 gene.
People inherit two copies of this gene, one from each biological parent. Certain variants can reduce the amount or function of alpha-1 antitrypsin.
The condition can therefore run in families.
Different genetic variants produce different levels of risk. Some people have severe deficiency, while others have moderately reduced levels and may develop few symptoms.
Effects on the Lungs
The lungs are among the organs most commonly affected by AATD.
AATD can increase the risk of developing emphysema, a form of chronic obstructive pulmonary disease in which the air sacs of the lungs become damaged.
Possible respiratory symptoms include:
- Shortness of breath
- Wheezing
- Persistent cough
- Reduced exercise tolerance
- Chest tightness
- Recurrent respiratory infections
Symptoms can appear at a younger age than is typical for smoking-related COPD in some individuals.
Effects of Smoking
Smoking is an especially important risk factor for people with AATD.
Tobacco smoke increases inflammation and can accelerate destruction of lung tissue. A person with AATD who smokes may therefore develop lung disease earlier or experience faster progression.
Avoiding smoking and secondhand smoke exposure is one of the most important steps for protecting lung health.
Liver Disease
Some forms of AATD can affect the liver.
Certain abnormal alpha-1 antitrypsin proteins can accumulate inside liver cells rather than being released normally into the bloodstream. This buildup can cause liver injury.
Possible liver-related conditions include:
- Elevated liver enzymes
- Fatty liver
- Fibrosis
- Cirrhosis
- Liver cancer in some affected individuals
Liver disease can occur even when significant lung symptoms are absent.
Symptoms in Children
AATD can occasionally cause liver problems during infancy or childhood.
Possible signs include:
- Jaundice
- Enlarged liver
- Poor growth
- Abnormal liver tests
Not every child with AATD develops significant liver disease.
How Is Alpha-1 Antitrypsin Deficiency Diagnosed?
Diagnosis generally involves blood testing and genetic or protein analysis.
Alpha-1 Antitrypsin Blood Test
A blood test can measure the amount of alpha-1 antitrypsin circulating in the bloodstream.
Low levels can indicate deficiency, although the level alone may not provide the complete picture.
Genetic Testing
Genetic testing can identify specific SERPINA1 variants.
This can help clarify the inherited form of AATD and may be particularly useful when blood levels are abnormal or family history suggests the condition.
Phenotype Testing
Additional testing can determine the type of alpha-1 antitrypsin protein present in the blood.
Combining blood levels with genetic and protein testing can provide a clearer understanding of the condition.
Lung Function Testing
People diagnosed with AATD may undergo pulmonary function testing.
Spirometry can measure how much air the lungs can move and how quickly it can be exhaled.
Other tests may include:
- Lung-volume measurements
- Diffusion testing
- Exercise testing
These tests can help determine whether lung function has been affected.
Imaging Tests
A CT scan of the chest may be used to evaluate lung structure and identify emphysema.
Liver imaging may also be recommended when liver involvement is suspected.
Treatment for Alpha-1 Antitrypsin Deficiency
There is currently no treatment that corrects the inherited genetic change responsible for AATD. Management focuses on protecting the lungs and liver, treating complications, and slowing disease progression.
Treatment depends on the organs affected and the severity of disease.
Smoking Cessation
Avoiding tobacco smoke is particularly important.
People with AATD who smoke can face substantially greater lung damage than nonsmokers with the condition.
Avoiding secondhand smoke, occupational dust, and certain chemical exposures may also help protect lung function.
Vaccinations
Vaccinations can reduce the risk of infections that may worsen underlying lung disease.
Depending on age and individual circumstances, healthcare professionals may recommend vaccinations against illnesses such as influenza, pneumococcal disease, COVID-19, and hepatitis.
Pulmonary Rehabilitation
For people with significant lung impairment, pulmonary rehabilitation can improve exercise tolerance and help with breathing techniques.
Programs may combine:
- Supervised exercise
- Breathing strategies
- Education
- Nutrition support
- Physical conditioning
The specific program depends on individual needs.
Inhaled Medications
People who develop airflow obstruction or COPD symptoms may receive inhaled medications.
These can include:
- Bronchodilators
- Inhaled corticosteroids in selected circumstances
- Combination inhalers
Medication choice depends on symptoms, lung function, exacerbation history, and other medical factors.
Alpha-1 Antitrypsin Replacement Therapy
Some people with severe AATD and established lung disease may qualify for intravenous alpha-1 antitrypsin augmentation therapy.
This treatment supplies purified alpha-1 antitrypsin through regular intravenous infusions.
Eligibility depends on factors such as genotype, blood alpha-1 antitrypsin level, lung function, and clinical guidelines.
Augmentation therapy is not appropriate for everyone with AATD and does not reverse existing emphysema.
Liver Disease Management
There is currently no routine augmentation therapy that removes abnormal alpha-1 antitrypsin from liver cells.
Management focuses on monitoring and treating liver complications.
This may include:
- Regular liver-function testing
- Imaging when appropriate
- Avoiding excessive alcohol
- Managing other liver-risk factors
- Monitoring for cirrhosis complications
Severe liver disease may eventually require liver transplantation.
Lung Transplantation
For advanced lung disease that severely limits daily activities despite other treatments, lung transplantation may be considered in selected individuals.
Eligibility depends on overall health, lung function, age, disease progression, and other factors.
Family Testing
Because AATD is inherited, relatives of someone diagnosed with the condition may benefit from discussing testing with a healthcare professional or genetic counselor.
Identifying AATD within a family can allow affected individuals to take steps to reduce avoidable lung and liver risks.
Living With Alpha-1 Antitrypsin Deficiency
Lifestyle measures can play an important role in long-term health.
Helpful measures may include:
- Avoiding smoking
- Maintaining regular physical activity
- Following recommended vaccinations
- Limiting exposure to respiratory irritants
- Maintaining a healthy weight
- Following recommended medical monitoring
- Reporting changes in breathing or liver-related symptoms
Regular follow-up can help identify changes in lung or liver health before complications become more advanced.
Prognosis
The outlook for AATD varies widely.
Some people remain relatively healthy throughout life, while others develop significant lung or liver disease.
Factors affecting prognosis can include:
- Genetic variant
- Alpha-1 antitrypsin level
- Smoking history
- Environmental exposures
- Existing lung function
- Liver involvement
- Access to appropriate treatment
Early identification can provide an opportunity to reduce avoidable risk factors and monitor organ health.
Conclusion
Alpha-1 antitrypsin deficiency is an inherited condition caused by changes in the SERPINA1 gene. Reduced or abnormal alpha-1 antitrypsin can increase vulnerability to lung damage and, in some genetic forms, cause liver disease.