antitrypsin (AAT) is a
protein normally found in the lungs and the
bloodstream. It helps protect the lungs from diseases such as
chronic obstructive pulmonary disease (COPD). Some people
do not make enough of this protein or they make an abnormal type of AAT, either of which can cause AAT deficiency. These people are more
likely to have lung diseases and will get them at a younger-than-normal
age (30 to 40 years old). Some types of abnormal AAT can also damage the liver. AAT deficiency is a
rare disorder and is the only known
genetic (inherited) factor that increases your chances
for developing emphysema.
Alpha-1 antitrypsin deficiency is caused
by a change, or mutation, in the
gene that tells the body how to make alpha-1
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 do not have the disease but 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 alpha-1
antitrypsin. Some people who carry the changed gene may have very mild symptoms
of the deficiency.
Treatment for alpha-1 antitrypsin deficiency
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. You may also need medicines and other treatments to help you breathe easier and stay as healthy and strong as you can.
The only treatment available for the
lack of the protein is
plasma containing alpha-1 antitrypsin. This is usually
given only to people who have very low levels of AAT 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
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.
What Is AAT Deficiency Testing?
A blood test can
measure the amount of alpha-1 antitrypsin (AAT) in your blood. You may have AAT
deficiency if your levels are low or if the blood test is not able to find any
AAT in your blood. If your AAT level is lower than normal, the blood sample can
be tested to look for abnormal types of alpha-1 antitrypsin. People who carry the
changed gene may be more at risk for symptoms if they have certain types of
Although this blood test is
highly reliable, no test is 100% accurate. This test cannot predict when—or
whether—you will develop symptoms or how severe they will be.
Should I Be Tested?
The decision to have the test is
personal. You may have emotional, financial, and family reasons for taking or
not taking the test.
You may choose to have the test
You have unexplained lung problems and want to
know whether you have this condition.
Other people in your family
have AAT deficiency.
Other people in your family have unexplained
lung disease or liver disease.
You want to take steps to protect
your health if you find out you have the condition.
You would be
relieved to know that you do not have the changed gene.
change your decision about having children because of test
Your insurance would pay for the test.
Why Would I Not Be Tested?
You may decide not to be
You do not have symptoms of lung
No one in your family has AAT deficiency or lung or liver
You would be worried if you knew that you might get lung
or liver disease some day.
You do not smoke and you already are
taking good care of yourself. You think there is nothing more you could do to
prevent or delay the disease.
The test cannot predict whether you
will ever have symptoms of this condition.
You do not have
insurance or your insurance would not pay for the test.
worried that the test results might cause problems for you at work or make it
hard for you to get health insurance. It's important to know that a law in the United States, called the Genetic Information Nondiscrimination Act of 2008 (GINA), protects people who have genetic differences that may affect their health. GINA prevents employers and health insurance companies from using genetic information about people to affect decisions. This law does not cover life insurance, disability insurance, or long-term care insurance.
What Is Genetic Counseling?
Information from genetic
testing can have a big impact on your life. Ask to have
genetic counseling before making a decision about
testing. Genetic counselors are trained to explain the test and its results,
but you make the decision about whether to have the test. A genetic counselor
can help you make well-informed decisions. Genetic counseling can help you and
Understand medical facts, including what causes
diseases, how a diagnosis is made, and what you may be able to do to help you
manage a disease.
Understand how your family history contributes to
the development of a disease.
Help you learn about caring for a
family member with a genetic disease, including getting referrals to
specialists or joining support groups.
Genetic counselors are trained to help you and your family
make informed decisions. They are sensitive to the physical and emotional
aspects of these decisions. Your privacy and confidentiality are carefully
Other Places To Get Help
U.S. National Library of Medicine: Genetics Home Reference
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Other Works Consulted
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
How this information was developed to help you make better health decisions.