Illustrated AAT protein in lung tissue environment

Less AAT protein.
Less lung protection.^1-3

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Alpha-1 antitrypsin deficiency (AATD) is a condition characterized by reduced production of the protein alpha-1 antitrypsin (AAT)²
Below-normal AAT levels can lead to irreversible lung damage and accelerated lung function decline^1,2,4
Genotype/alleles correlate with AAT levels and primarily contribute to risk of disease progression, along with smoking, air pollution, and dust exposure^1,5-7

When AAT levels are below normal, the lungs may become increasingly susceptible to irreversible damage^1,4

Alpha-1 antitrypsin deficiency (AATD) is characterized by reduced production of alpha-1 antitrypsin (AAT). Genotypes and AAT protein levels primarily contribute to risk and disease progression in AATD.^1,5 Smoking, air pollution, and dust exposure are also contributing factors to increased risk of accelerated lung disease.^6,7

Flow chart step 1: DNA icon representing genetics, with pink arrow pointing to step 2

Flow chart step 2: AAT protein icon with a downward arrow representing lower levels, and a separate pink arrow pointing to step 3

Flow chart step 3: Graph with downward trending data and an upward arrow representing increased risk of disease progression, and a separate pink arrow pointing to step 4

Flow chart step 4 (final step): Lung icon with a downward arrow representing lung decline

Genotype/alleles and AAT levels correlate. While protein levels vary with factors such as inflammation, literature supports that genotype is indicative of the typical range of AAT levels^1,2

Genotypes & AAT Levels

Understanding risk begins with defining the underlying genetics and potential deficiency of AAT protein.^1,5

Learn about the importance of genotypes

Consequences of AATD

AATD may lead to a poor prognosis with increased exacerbations and a shorter lifespan.^8-11

Explore the pulmonary impact

Testing & Management

Guidelines recommend testing all patients with COPD for AATD.^1,2,12

Review AATD testing guidance

Frequently asked questions

What is alpha-1 antitrypsin deficiency (AATD)?

What happens when AAT levels are below normal?

How do genetics affect AAT levels?

Is disease progression in AATD only influenced by genetics?

What are the key risk factors for accelerated lung function decline in AATD?

Definitions: AAT=alpha-1 antitrypsin; AATD=alpha-1 antitrypsin deficiency; COPD=chronic obstructive pulmonary disease.

References: 1. American Thoracic Society; European Respiratory Society. American Thoracic Society/European Respiratory Society Statement: Standards for the Diagnosis and Management of Individuals with Alpha-1 Antitrypsin Deficiency. Am J Respir Crit Care Med. 2003;168(7):818-900. 2. Sandhaus RA, Turino G, Brantly ML, et al. The diagnosis and management of alpha-1 antitrypsin deficiency in the adult. Chron Obstr Pulm Dis. 2016;3(3):668-682. 3. Mulkareddy V, Roman J. Pulmonary manifestations of alpha 1 antitrypsin deficiency. Am J Med Sci. 2024;368(1):1-8. 4. Meseeha M, Sankari A, Attia M. Alpha-1 antitrypsin deficiency. In: StatPearls [Internet]. StatPearls Publishing; August 17, 2024. Accessed March 4, 2026. https://www.ncbi.nlm.nih.gov/books/NBK442030/ 5. Feitosa PHR, de Oliveira Castellano MVC, da Costa CH, et al. Recommendations for the diagnosis and treatment of alpha-1 antitrypsin deficiency. J Bras Pneumol. 2024;50(5):e20240235. doi:10.36416/1806-3756/e20240235 6. Torres-Durán M, Lopez-Campos JL, Barrecheguren M, et al. Alpha-1 antitrypsin deficiency: outstanding questions and future directions. Orphanet J Rare Dis. 2018;13(1):114. doi:10.1186/s13023-018-0856-9 7. Wang T, Shuai P, Wang Q, et al. α‑1 antitrypsin is a potential target of inflammation and immunomodulation. Mol Med Rep. 2025;31(4):107. doi:10.3892/mmr.2025.13472 8. Vijayasaratha K, Stockley RA. Reported and unreported exacerbations of COPD: analysis by diary cards. Chest. 2008;133(1):34-41. doi:10.1378/chest.07-1692 9. Donaldson GC, Seemungal TA, Patel IS, Lloyd-Owen SJ, Wilkinson TM, Wedzicha JA. Longitudinal changes in the nature, severity and frequency of COPD exacerbations. Eur Respir J. 2003;22(6):931-936. doi:10.1183/09031936.03.00038303 10. Stoller JK, Tomashefski J Jr, Crystal RG, et al. Mortality in individuals with severe deficiency of α1-antitrypsin: findings from the National Heart, Lung, and Blood Institute Registry. Chest. 2005;127(4):1196-1204. 11. Wahlin S, Widman L, Hagström H. Epidemiology and outcomes of alpha-1 antitrypsin deficiency in Sweden 2002-2020: a population-based cohort study of 2286 individuals. J Intern Med. 2025;297(3):300-311. doi:10.1111/joim.20058 12. Global Initiative for Chronic Obstructive Lung Disease. GOLD Report. Accessed February 3, 2026. https://goldcopd.org

Less AAT protein. Less lung protection.1-3

When AAT levels are below normal, the lungs may become increasingly susceptible to irreversible damage1,4