Alpha-1 antitrypsin deficiency is an inherited disorder that may cause lung disease and liver disease. Alpha-1 antitrypsin deficiency occurs worldwide, but its prevalence varies by population. This disorder affects about 1 in 1,500 to 3,500 individuals with European ancestry. COPD can be caused by alpha-1 antitrypsin deficiency. Some people with alpha-1 antitrypsin deficiency are misdiagnosed with asthma. Mutations in the SERPINA1 gene can lead to a shortage (deficiency) of alpha-1 antitrypsin or an abnormal form of the protein that cannot control neutrophil elastase. Most common mutations are PIZ and PIS (http://ghr.nlm.nih.gov).