Ahpra registration PHY0002298174
How these guides are written and reviewed →
Alpha-1 antitrypsin deficiency is an inherited condition in which the body lacks enough of a protein that protects the lungs from damage. As a result, some people develop emphysema (a type of COPD) earlier than usual, particularly if they smoke, and it can also affect the liver. A simple blood test can detect it, and family members may wish to be tested. Management focuses on protecting the lungs — never smoking, vaccinations and staying active — and sometimes replacing the missing protein. This page explains the condition, its effects and how it is managed.
Alpha-1 antitrypsin deficiency (A1ATD) is the most common genetic risk factor for COPD and a treatable cause of emphysema and liver disease. It is significantly under-diagnosed in Australia and warrants its own dedicated page on the website.
Definition
Alpha-1 antitrypsin deficiency is an inherited disorder caused by mutations in the SERPINA1 gene, resulting in reduced or dysfunctional alpha-1 antitrypsin (AAT). AAT is a circulating serine protease inhibitor whose main role is to neutralise neutrophil elastase in the lung. Deficiency permits unopposed proteolytic damage to the alveolar wall and predisposes to early-onset emphysema, bronchiectasis, and liver disease.1
Pathophysiology
Most clinically significant disease results from the Z allele, which causes AAT to misfold and polymerise within hepatocytes. The retained protein damages the liver, while reduced circulating AAT permits unopposed neutrophil elastase activity in the lung. The result is panlobular emphysema (typically lower-zone predominant), bronchiectasis, and a spectrum of liver disease from elevated enzymes to cirrhosis and hepatocellular carcinoma.
Co-morbidities
Co-morbid conditions include liver disease (across the lifespan, from neonatal cholestasis to adult cirrhosis), bronchiectasis, panniculitis, and ANCA-associated vasculitis. Asthma and chronic rhinosinusitis are also more frequent.
Prevalence
Severe deficiency (PiZZ genotype) affects approximately 1 in 2,500 to 1 in 5,000 people of European ancestry. Australian prevalence is estimated similarly, though many cases remain undiagnosed. GOLD recommends measuring AAT at least once in every patient diagnosed with COPD.
Causes — phenotypes and genotypes
Common alleles include M (normal), S (mild reduction), and Z (severe reduction). The principal phenotypes are:
- PiMM — normal.
- PiMS — usually clinically silent.
- PiMZ — mild reduction in AAT level; modest increased risk in smokers.
- PiSZ — intermediate risk.
- PiZZ — severe deficiency; the major risk genotype for emphysema and liver disease.
- Rare null alleles — produce undetectable AAT and carry the highest pulmonary risk.
Symptoms
Pulmonary symptoms typically present in adulthood (often 30s–50s in smokers) with progressive dyspnoea, cough and sputum production. Liver disease may present in infancy (neonatal cholestasis), childhood, or adulthood (transaminase abnormalities, cirrhosis, hepatocellular carcinoma). Many patients are asymptomatic until significant damage has occurred.
Family screening
A diagnosis of A1ATD in one family member warrants offer of testing to first-degree relatives, with appropriate genetic counselling. Early identification permits lifelong smoking avoidance and surveillance.
Diagnosis
Importance of a diagnosis
A confirmed diagnosis enables lifelong smoking avoidance (the single most important intervention), consideration of augmentation therapy, surveillance for liver disease and hepatocellular carcinoma, family screening, and access to peer support and registries (e.g. AlphaNet Australia).
How is it diagnosed?
Testing should be considered in every patient with COPD (regardless of smoking history), early-onset emphysema (under 45 years), basal-predominant emphysema, bronchiectasis of unclear cause, unexplained liver disease, family history of A1ATD, and certain forms of vasculitis. Diagnosis combines serum AAT level with phenotyping (isoelectric focusing) or genotyping for common alleles.2
Radiology
HRCT classically shows panlobular emphysema with lower-zone (basal) predominance, distinguishing it from the upper-zone, centrilobular pattern of typical smoking-related emphysema. Bronchiectasis is also commonly seen.
Lung function
Full pulmonary function testing typically reveals an obstructive pattern with reduced FEV1/FVC, increased lung volumes from hyperinflation, and reduced DLCO. Lung function decline tends to be more rapid in smokers and is dramatically slowed by smoking cessation.
Liver function and imaging
Liver function tests should be performed at diagnosis and annually thereafter. Liver ultrasound is recommended as a baseline and periodically for hepatocellular carcinoma surveillance in advanced liver disease. FibroScan or formal fibrosis assessment may be used to characterise liver disease.
Investigations for related conditions
In selected patients, additional investigations include ANCA serology (for vasculitis), skin biopsy (panniculitis), and assessment for bronchiectasis with HRCT and sputum culture.
Management
Management and goals
Goals are to: preserve lung function (above all else through complete avoidance of tobacco and other inhalational toxins), reduce exacerbation frequency, improve quality of life, monitor and manage liver disease, and provide access to family screening and disease-specific therapies.
Treatment options
Treatment includes:
- Lifelong avoidance of tobacco smoke and inhalational toxins — the single highest-impact intervention.
- Standard COPD pharmacotherapy (LAMA, LABA, and ICS when indicated).
- Pulmonary rehabilitation.
- Vaccinations — annual influenza, pneumococcal and COVID-19.
- IV augmentation therapy with pooled human AAT in selected patients (PiZZ, FEV1 30–65% predicted, non-smoking) — not PBS-subsidised and not routinely available in Australia; access is through special access or compassionate supply pathways on individual assessment.
- Treatment of bronchiectasis where present.
- Hepatology surveillance and management of liver disease.
- Lung transplantation in advanced disease.
- Investigational therapies (siRNA and CRISPR approaches) are in development.3,4
Identifying an exacerbation
Exacerbations are recognised as in COPD, with acute worsening of dyspnoea, cough, or sputum. Patients with A1ATD may have more frequent or severe exacerbations and benefit particularly from a structured action plan.
Action plan
A written action plan with self-monitoring guidance, escalation steps for increased symptoms, criteria for commencement of pre-supplied antibiotics and corticosteroids where appropriate, and clear hospital triggers.
Medications
Medications for A1ATD
In addition to standard COPD inhaled therapies, the disease-specific therapy is IV augmentation with pooled human AAT (60 mg/kg weekly). It raises serum AAT levels above the protective threshold and slows the rate of CT-measured emphysema progression. It does not reverse existing damage and does not treat the liver disease.
Correct use of medications
Inhaler technique is reviewed and reinforced as in COPD. Augmentation therapy is delivered as a weekly IV infusion, typically with home-based delivery once tolerance is established. Patients should understand that augmentation therapy does not protect against smoke-induced damage.
Order of medications
For routine inhaled therapy, the order parallels COPD: bronchodilator first, airway clearance if needed, ICS (where indicated) with mouth rinse afterwards.
Multi-system manifestations
Liver disease
A1ATD is the leading genetic cause of liver disease in children. In adults, the spectrum ranges from transaminase elevation through advanced fibrosis to cirrhosis and hepatocellular carcinoma. Avoidance of alcohol and hepatotoxic medications, maintenance of healthy weight, and surveillance for HCC are core.
Bronchiectasis
A1ATD is an under-recognised cause of bronchiectasis. The bronchiectasis pathway above applies, with the addition of A1ATD-directed therapy.
Panniculitis
Necrotising panniculitis is a rare but characteristic manifestation, presenting with painful, ulcerating skin lesions. It usually responds to augmentation therapy.
Vasculitis
ANCA-associated vasculitis (particularly granulomatosis with polyangiitis) is more common in people with A1ATD. Suggestive features (renal involvement, haemoptysis, ENT symptoms) warrant urgent specialist referral.
Living with A1ATD
Nutrition
Maintenance of healthy weight, adequate protein intake to preserve muscle mass, and avoidance of alcohol (which compounds liver injury) are the dietary cornerstones.
Sleep
Sleep-related breathing disorders should be screened for as in COPD, particularly where there is significant emphysema or hypercapnia.
Travel
In-flight oxygen requirements should be assessed where lung function is impaired. Continuity of augmentation therapy may require coordination with international centres for prolonged travel.
Prognosis
Prognosis is highly variable. Lifelong non-smokers may have near-normal life expectancy; smokers with PiZZ have substantially reduced life expectancy. Smoking cessation is by far the most important determinant of outcome.
Anxiety, depression and the diagnostic journey
A diagnosis often follows years of delay and explains symptoms attributed to other causes. Adjustment, anxiety and depression are common, particularly when the diagnosis has implications for family members. Peer support through patient organisations is valuable.
Role of the physiotherapist
Physiotherapy in A1ATD mirrors COPD and bronchiectasis care: pulmonary rehabilitation and ongoing exercise, breathing retraining and pacing for breathlessness, airway clearance where sputum or bronchiectasis is present, inhaler-technique review, and self-management education — reinforcing that lifelong smoking avoidance is the single most important step.5
Warning signs
Part 1 · References
- Miravitlles M, Dirksen A, Ferrarotti I, et al. European Respiratory Society statement: diagnosis and treatment of pulmonary disease in alpha-1 antitrypsin deficiency. Eur Respir J 2017;50(5):1700610.
- Sandhaus RA, Turino G, Brantly ML, et al. The diagnosis and management of alpha-1 antitrypsin deficiency in the adult. Chronic Obstr Pulm Dis 2016;3(3):668–682.
- Chapman KR, Burdon JGW, Piitulainen E, et al; RAPID Trial Study Group. Intravenous augmentation treatment and lung density in severe α1 antitrypsin deficiency (RAPID): a randomised, double-blind, placebo-controlled trial. Lancet 2015;386(9991):360–368.
- McElvaney NG, Burdon J, Holmes M, et al; RAPID Extension Trial Group. Long-term efficacy and safety of α1 proteinase inhibitor treatment for emphysema caused by severe α1 antitrypsin deficiency: an open-label extension trial (RAPID-OLE). Lancet Respir Med 2017;5(1):51–60.
- McCarthy C, Brennan S, Ryan A, et al. Pulmonary rehabilitation in alpha-1 antitrypsin deficiency: a review of exercise and outcome. Chronic Respir Dis 2019;16:1479973119872973.
References are numbered in citation order (Vancouver/BMJ style) and were current at the time of writing. Guidelines are living documents — verify against the latest version before clinical use.
Supervised exercise, breathing technique and self-management education are the mainstay of cardiorespiratory physiotherapy for this condition.
Clinical evidence
Part 1 covers the same condition without the technical detail. What follows is the evidence base behind it, written for clinicians — the literature, the reasoning and the gaps.
For clinicians: this summary supports clinical reasoning and is not a protocol. Check current guidelines and local policy before applying it, and read it alongside the key references and guidelines directory.
Framing. Alpha-1 antitrypsin deficiency is the one common genetic cause of COPD, and it changes three matters clinically: it produces early-onset, often basal-predominant emphysema; it makes smoking exposure far more damaging; and it brings a disease-modifying therapy (augmentation) that non-deficient COPD does not have. Under-diagnosis remains the central problem — guidelines recommend testing all adults with fixed airflow obstruction at least once.1,2
Diagnosis and case-finding
- Test with serum AAT level plus phenotype/genotype; a normal level during an acute inflammatory episode can mislead, as AAT is an acute-phase protein.1
- ZZ and other severe-deficiency genotypes carry the greatest risk; MZ carriers have modestly increased susceptibility, mainly in the presence of smoking.2
- Family screening and genetic counselling follow a positive result, and matter more here than in usual COPD.
- Suspect it in emphysema before age 50, basal or panlobular distribution, minimal smoking history, unexplained liver disease, or a family history.1
Disease-modifying and supportive therapy
- Intravenous augmentation therapy slows the progression of CT-measured lung-density loss (RAPID and its extension), although effects on FEV1 decline and exacerbations are less clear-cut; it is reserved for severe deficiency with established emphysema.3,4
- Smoking cessation is the single most important intervention, and passive-exposure avoidance matters more than in usual COPD.2
- Otherwise, standard COPD care applies: inhaled therapy, vaccination, exacerbation planning and pulmonary rehabilitation. Lung volume reduction and transplantation are considered in advanced disease, with basal-predominant distribution influencing candidacy.
Physiotherapy implications
- Pulmonary rehabilitation is as effective here as in usual COPD, and often more valuable because patients are younger, working and have longer to gain from it — see Cardiorespiratory Rehabilitation.5
- Basal-predominant emphysema means hyperinflation and diaphragm mechanics dominate; expect dynamic hyperinflation on exertion and use pacing, pursed-lip breathing and interval training accordingly.
- Screen for bronchiectasis, which coexists more often than in usual COPD, and add an airway-clearance regimen where sputum is a genuine feature rather than assumed.
- Occupational and lifestyle counselling carries weight: dust, fume and solvent exposure should be discussed explicitly in a young worker with a genetic susceptibility.
- Psychosocial load is different — a hereditary diagnosis in mid-life, implications for children, and infusion burden all belong in the conversation.
Evidence gaps
- Whether augmentation therapy alters exacerbation frequency, exercise capacity or mortality remains unproven; density loss is a surrogate.
- No trials examine exercise training or airway clearance specifically in AATD populations.
- Optimal management of MZ heterozygotes, and of AATD with coexisting bronchiectasis, is undefined.
References for the clinical evidence summary
- Miravitlles M, Dirksen A, Ferrarotti I, et al. European Respiratory Society statement: diagnosis and treatment of pulmonary disease in alpha-1 antitrypsin deficiency. Eur Respir J 2017;50(5):1700610.
- Sandhaus RA, Turino G, Brantly ML, et al. The diagnosis and management of alpha-1 antitrypsin deficiency in the adult. Chronic Obstr Pulm Dis 2016;3(3):668–682.
- Chapman KR, Burdon JGW, Piitulainen E, et al; RAPID Trial Study Group. Intravenous augmentation treatment and lung density in severe α1 antitrypsin deficiency (RAPID): a randomised, double-blind, placebo-controlled trial. Lancet 2015;386(9991):360–368.
- McElvaney NG, Burdon J, Holmes M, et al; RAPID Extension Trial Group. Long-term efficacy and safety of α1 proteinase inhibitor treatment for emphysema caused by severe α1 antitrypsin deficiency: an open-label extension trial (RAPID-OLE). Lancet Respir Med 2017;5(1):51–60.
- McCarthy C, Brennan S, Ryan A, et al. Pulmonary rehabilitation in alpha-1 antitrypsin deficiency: a review of exercise and outcome. Chronic Respir Dis 2019;16:1479973119872973.
Corrections: If something on this page is wrong, out of date or unclear, we want to know. Email reception@inspireclinic.au with the page name and what you believe is incorrect. Substantive corrections are made promptly, and the guide’s version and last-updated date are changed to reflect it.