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Genetic and Rare Diseases Information Center (GARD)

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Alpha 1-antitrypsin deficiency

Other Names for this Disease
  • A1AT deficiency
  • AAT deficiency
  • AATD
  • Alpha 1 antitrypsin deficiency
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Your Question

I think I may have alpha-1-antitrypsin deficiency. How is it diagnosed? Who should I talk to?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is alpha 1-antitrypsin deficiency?

Alpha 1-antitrypsin deficiency is an inherited disorder that can cause lung disease in adults and liver disease in adults and children.[1] Alpha-1 antitrypsin (AAT) is a protein that protects the lungs. The liver usually makes the protein, and releases it into the bloodstream.[2] Because of a mutation in the SERPINA1 gene, some people have little or no AAT.[1][2] Not having enough AAT may lead to emphysema or liver problems. Smoking increases the risk. A deficiency of AAT can be treated but not cured. One treatment involves adding to or replacing the missing protein. More severe cases may require a lung transplant.[2] This condition is caused by mutations in the SERPINA1 gene and inherited in an autosomal co-dominant fashion.[1]
Last updated: 7/26/2011

How is alpha-1-antitrypsin deficiency diagnosed?

Alpha1-antitrypsin deficiency is suspected in people with evidence of lung disease (i.e., emphysema, asthma, persistent airflow obstruction, and/or chronic bronchitis) and/or evidence of liver disease at any age. The diagnosis of Alpha1-antitrypsin deficiency relies on the demonstration of low plasma concentration of alpha1-antitrypsin and observation of a deficient variant of the protein AAT by protease inhibitor (PI) typing OR detection by molecular genetic testing of mutations in both copies of SERPINA1, the gene encoding AAT.[3]

For a comprehensive review of Alpha1-antitrypsin deficiency including its diagnosis, you can visit GeneReviews at the following link. GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.

You can also learn more about Alpha1-antitrypsin testing on the Lab Tests Online Web site. A public resource developed by the American Association for Clinical Chemistry.

Last updated: 7/26/2011

Who should I talk to if I think I may have alpha-1-antitrypsin deficiency?

You may wish to discuss your concerns with a genetics professional. Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference at To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:  

Last updated: 7/26/2011