Viral Hepatitis and Liver Disease Website Course
Evaluating Liver Test Abnormalities
Understanding the Pathophysiology of Liver Disease
for Health Care Providers
Alpha-1 Antitrypsin Deficiency
Alpha-1 antitrypsin (AAT) is a protease inhibitor of the enzyme elastase. In lungs, AAT deficiency leads to progressive fibrosis. In liver, there is a polymerization and accumulation of an abnormal variant of AAT, leading to hepatocellular injury.
There are no physical findings diagnostic of AAT deficiency. The initial test is serum AAT level. Genetic phenotyping is used to confirm the diagnosis of alpha-1 antitrypsin deficiency if serum AAT is low.