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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
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 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.
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
100–200 mg/dL or 1.0–2.0
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.
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 may decide not to be
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
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
The Genetics Home Reference provides information on hundreds of genetic conditions. The website has many tools for learning about human genetics and the way genetic changes can cause
disease. It also has links to additional resources for people who
have genetic conditions and for their families.
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.
November 29, 2011
E. Gregory Thompson, MD - Internal Medicine & Ken Y. Yoneda, MD - Pulmonology
How this information was developed to help you make better health decisions.
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