Alpha-1 antitrypsin deficiency (AATM) is a congenital metabolic disorder. It is caused by a genetic defect, which results in the protective protein alpha-1 antitrypsin (AAT) being produced incorrectly. This deficiency primarily damages the lungs and the liver, where it can lead to serious conditions such as pulmonary emphysema, liver fibrosis or cirrhosis. In particularly severe cases, an organ transplant is the last resort. There is as yet no curative treatment.