While emphysema is most often connected with smoking cigarettes, not everyone who has emphysema, a form of COPD (chronic obstructive pulmonary disease), acquires it from smoking or other external factors like air pollution or work in factories with chemical fumes. A genetic disorder called Alpha-1 Antitrypsin Deficiency (known as A1AD or AAT) can cause emphysema in people with no other risk factors. 
Fortunately, with early detection and treatment, A1AD is treatable.
Genetics and Alpha-1 Antitrypsin Deficiency
While only 1-5% of people with COPD have alpha-1 antitrypsin deficiency, it should be considered as a cause if a person has no other risk factors for emphysema, and develops the condition at a younger age (between 20 and 50 years old).  In A1AD, there is an incorrectly formed branch on the 14th chromosome that impairs the production of alpha-1 antitrypsin in the liver.  Early stages of A1AD can be so mild, that a person may not know they have it. 
In emphysema caused by cigarette smoking, the alveoli (air sacs) in the lungs become stretched out. In A1AD, alpha-1 antitrypsin is needed to counteract an enzyme that affects lung elasticity. Without the check of alpha-1 antitrypsin on this enzyme, lung tissue becomes damaged and stretched, similar to how it would following prolonged exposure to the toxins in cigarettes. In this way, A1AD begins to develop earlier than it would otherwise, such as in cases linked to smoking or air pollution.
Genetic tests can be done to diagnose alpha-1 antitrypsin deficiency. These tests are done by analyzing both blood and the genes themselves. A blood test can detect the level of alpha-1 antitrypsin in the body Tests should be done for anyone with a known family history of the genetic disorder, or any disease of the lungs or liver, as A1AD arises of liver disease, where alpha-1 antitrypsin is produced. 
Children with otherwise unexplained liver diseases should be tested for A1AD.  In other cases, people may experience decreased tolerance for exercise (which may be a dramatic or marked decrease from pervious abilities), swelling of the limbs, and symptoms including shortness of breath, wheezing, chest tightness, or coughing, that cannot otherwise be explained, should be screened for A1AD—symptoms may seem similar to those of asthma, but can occur in those with no history of asthma. 
If genetic testing reveals one family member to be deficient in alpha-1 antitrypsin, other family members should be tested. The earlier A1AD is treated, the better.
Often, A1AD is treated with augmentation therapy, where infusions of alpha-1 antitrypsin are received—augmentation therapy is only given in cases where lung disease has developed from A1AD.  Medicine will be given to assist with breathing, and in some cases, oxygen therapy is required. In severe cases of lung and liver disease, transplantation of the lungs and/or liver may be needed. Preventative and rehabilitative measures, including vaccines for hepatitis A and B, and undergoing pulmonary rehabilitation to learn how to keep your lungs as healthy as possible through exercise, may also be important parts of treating alpha-1 antitrypsin deficiency.
Information on this page is for reference and educational purposes only. For more information about Alpha-1 Antitrypsin Deficiency, talk to your doctor or primary care provider.
Page last updated: October 22, 2018
 Medscape. Alpha1 Antitrypsin Deficiency. https://emedicine.medscape.com/article/295686-overview
 National Institutes of Health - Genetics Home Reference. Alpha-1 Antitrypsin Deficiency. https://ghr.nlm.nih.gov/condition/alpha-1-antitrypsin-deficiency
 National Institutes of Health - National Center for Biotechnology Information (NCBI). Genes and disease. https://www.ncbi.nlm.nih.gov/books/NBK22199/
 Alpha1 Foundation. What Now? Living with Alpha-1. Treatment. https://www.alpha1.org/Newly-Diagnosed/Living-with-Alpha-1/Treatment
 Alpha1 Foundation. Liver Disease. https://www.alpha1.org/Newly-Diagnosed/Learning-about-Alpha-1/Liver-Disease
 Alpha1 Foundation. Liver Disease. https://www.alpha1.org/Newly-Diagnosed/Learning-about-Alpha-1/Lung-Disease
 Lab Tests Online. Alpha-1 Antitrypsin. https://labtestsonline.org/tests/alpha-1-antitrypsin
 WebMD. Alpha-1 Antitrypsin Deficiency Starts in the Liver. https://www.webmd.com/lung/copd/liver#2-5
 National Institutes of Health - National Heart, Lung and Blood Institute (NHLBI). Alpha-1 Antitrypsin Deficiency. https://www.nhlbi.nih.gov/health-topics/alpha-1-antitrypsin-deficiency