SERPINA1 PI*Z — Alpha-1 antitrypsin deficiency
One copy of the SERPINA1 PI*Z variant — Alpha-1 antitrypsin deficiency carrier.
You have one copy of the SERPINA1 Z version, making you a carrier for alpha-1 antitrypsin deficiency.
Heterozygous PI*MZ carriers are usually asymptomatic but have somewhat lower circulating Alpha-1 antitrypsin and a slightly increased lifetime risk of COPD, especially if they smoke.
With one Z copy and one normal copy, you usually have no symptoms, but the level of alpha-1 antitrypsin in your blood is a bit lower than normal and your lifetime risk of COPD is slightly raised — especially if you smoke.
What this means
Alpha-1 antitrypsin protects the lungs from neutrophil elastase. The Z variant produces a misfolded protein that polymerises in the liver and is secreted poorly. PI*ZZ individuals are at high risk of early-onset emphysema (often in their 40s, much earlier if they smoke) and a smaller but real risk of liver disease. PI*MZ heterozygotes have a milder picture and are often asymptomatic unless exposed to smoke. Diagnosis is highly actionable: smoking cessation and avoidance of dust/fumes are primary, and IV augmentation therapy is available for severe cases.
Alpha-1 antitrypsin is a protein your liver makes that protects your lungs from being broken down by an enzyme your immune cells release. The Z version of this protein doesn't fold properly, gets stuck in the liver, and barely reaches the bloodstream. People with two Z copies are at high risk of early-onset emphysema, often appearing in their 40s and much earlier if they smoke, plus a real chance of liver disease. People with one Z copy and one normal copy have a milder picture and are often fine unless they smoke or breathe in dust and fumes regularly. This is one of the more actionable genetic findings out there: not smoking and avoiding lung irritants are the main levers, and there's also a treatment that infuses the missing protein for severe cases.
Caveats
- Confirm with serum AAT level and protein phenotyping before any clinical decision.
- Smoking and occupational dust exposure dramatically affect outcomes — avoidable triggers are the primary lever.
- Carrier (PI*MZ) status has implications for family planning.
References
- Stoller & Aboussouan — A review of α1-antitrypsin deficiency (American Journal of Respiratory and Critical Care Medicine, 2012)
- American Thoracic Society / European Respiratory Society Statement: Standards for the diagnosis and management of individuals with alpha-1 antitrypsin deficiency (AJRCCM, 2003)