Alpha-1 Antitrypsin Deficiency (AATD) is a genetic disorder resulting in a low level of a protein called alpha-1 antitrypsin (AAT). This deficiency can cause life-threatening liver disease and/or lung disease at various ages. Some patients experience life-threatening liver disease in childhood or liver cancer as adults. There is no specific treatment for AAT related liver disease. Some patients develop emphysema as young adults, while some patients remain healthy throughout their lives. Differences in the environment or in other genes may explain such inconsistency in the disease.