Alpha1-antitrypsin (AAT) is a protein normally found in the lungs and the bloodstream. It helps protect the lungs from diseases such as emphysema and chronic obstructive pulmonary disease (COPD). People who do not make enough of this protein-this is called AAT deficiency-are more likely to have these lung diseases and will get them at a younger-than-normal age (30 to 40 years old). AAT deficiency is a rare disorder and is the only known genetic (inherited) factor that increases your chances for having lung diseases.

Alpha1-antitrypsin deficiency is caused by a change, or mutation, in the gene that tells the body how to make alpha1-antitrypsin. There are many kinds of possible changes in this gene, but only a few cause problems. To have this condition, you have to get the changed gene from both parents.

If you receive only one changed gene, you have the changed gene but not the disease (you are a carrier). The good copy of the gene you received from your other parent is enough to tell your body how to properly make alpha1-antitrypsin.

Some people who carry the changed gene may have very mild symptoms of the deficiency. If you are one of these people, you may pass the changed gene to your children.

Treatment for alpha1-antitrypsin deficiency mainly involves avoiding substances-especially cigarette smoke-that could harm your lungs. Also try to avoid dust and workplace chemicals. You also may want to avoid alcohol because of the risk of liver damage. Exercise can improve your stamina and overall health.

The only treatment available for the lack of the protein is plasma containing alpha1-antitrypsin. This is usually given only to people who have very low levels of alpha1-antitrypsin in their blood. It is not clear that this treatment is any better than avoiding smoke and other lung-damaging chemicals. The plasma is made from the blood of many donors and it is treated to reduce the chance of spreading an infectious disease. You receive the plasma through an IV, usually every 3 to 4 weeks for life.