ThalassemiaTopic Overview
What is thalassemia?
Thalassemia (say "thal-uh-SEE-mee-uh") is an
inherited blood disorder that causes the body to produce less
hemoglobin.
Hemoglobin helps red blood cells spread oxygen all
through your body. Low levels of hemoglobin may cause anemia, an illness that
makes you feel weak and tired. Severe cases of anemia may damage organs and
result in death.
What causes thalassemia?
A defect in one or more
genes causes thalassemia. It is an inherited blood
disorder, passed from parent to child. Both parents must carry a gene for the
disease in order to pass it to their child.
What are the types of thalassemia?
Alpha thalassemia and beta thalassemia are the two main types of
the disease. Beta is the most common form. A "carrier" has one normal gene and
one thalassemia gene in all body cells, a state sometimes called "thalassemia
trait." Most carriers lead completely normal, healthy lives. Beta thalassemia Beta thalassemia occurs when one or both of the genes that
produce beta-globin don't work or only partly work the way they should. People
need both alpha- and beta-globin to make hemoglobin. Beta thalassemia mainly
affects people from the region around the Mediterranean Sea (such as Greeks and
Italians) and, less often, people of African or Asian descent.
There are several subtypes of beta thalassemia. Which type you
have depends upon whether one or both genes are affected and whether those
genes still produce some working beta-globin. - If you carry the genetic trait for
thalassemia or have one damaged beta-globin gene, you may have mild anemia and
probably will not need treatment. This condition is called beta thalassemia minor or beta thalassemia trait. You
have thalassemia trait when you inherit a normal gene from one parent and a
thalassemia gene from the other.
- When both beta-globin genes are
damaged, moderate or severe anemia may develop. In this situation, you have
inherited a thalassemia gene from each parent.
- If you have moderate anemia (beta thalassemia intermedia), you may need
blood transfusions. People who have beta thalassemia
intermedia usually live into adulthood.
- People with severe anemia
(called beta thalassemia major or Cooley's anemia) usually will not live into adulthood without
treatment. Symptoms of anemia usually develop within 6 months of birth.1 If the child starts receiving blood transfusions early and
continues to receive them throughout life, he or she is likely to live longer.
Death is usually a result of damage to organs, such as the heart or liver. Lack
of oxygen or an iron overload from blood transfusions causes the organ
damage.
Alpha thalassemia Alpha thalassemia occurs when one or more of the four genes that
are vital to making hemoglobin are missing or damaged. Alpha thalassemia mainly
affects people from southeast Asia, China, and the Philippines, although it
occurs in many populations throughout the world. It is sometimes seen in people
of African descent. There are four subtypes of alpha thalassemia. Each type
represents the loss of or damage to one, two, three, or four genes. -
One gene: If one
alpha-globin gene is missing or damaged, you will have no symptoms and will not
need treatment. But you are a silent carrier. This means
you don't have the disease but you can pass the defective gene onto your child.
Smaller-than-normal blood cells may be the only sign of the condition.
-
Two genes: If two alpha-globin genes are
missing or damaged, you will have very mild
anemia that will not need treatment. This is known as
alpha thalassemia minor or alpha thalassemia trait.
-
Three genes: If
three alpha-globin genes are missing, you will have mild to moderately severe
anemia. This is sometimes called hemoglobin H disease,
because it produces a heavy hemoglobin. The body removes this heavy hemoglobin
faster than it does normal hemoglobin. The more severe forms may need treatment
with
blood transfusions.
-
Four genes: If all four alpha-globin genes are missing (alpha thalassemia major), the fetus will be stillborn or the child will die
shortly after birth.1 The hemoglobin produced by this
condition is sometimes called hemoglobin Barts.
What are the symptoms?
Mild thalassemia usually does not cause any symptoms. But symptoms
of anemia may develop in more severe forms of the condition and may
include: - Weakness.
- Fatigue.
- Lightheadedness.
- Skin that looks paler than normal.
- Jaundice (skin and whites of the eyes appear
yellow).
- Dark urine.
- Decreased appetite and weight loss
(poor growth in a child).
- A rapid heartbeat.
- Shortness
of breath during exercise.
How is thalassemia diagnosed?
A physical exam and complete medical history are usually the first
steps in diagnosing thalassemia. Tests that help confirm a diagnosis of
thalassemia include: -
Complete blood count (CBC) and blood smear.
-
Gene
test.
- Iron level test, to determine whether
iron deficiency anemia is present.
- A
blood test that measures the amounts of different types of hemoglobin
(hemoglobin electrophoresis), to help find out which type of thalassemia you
have.
- A complete blood count (CBC) test on other members of your
family (parents and siblings), to discover whether they may also have
thalassemia.
How is it treated?
Treatment for thalassemia depends on your symptoms. - Mild thalassemia, the most common form, does
not need treatment.
- Moderate thalassemia may be treated with
folic acid supplements and
blood transfusions.
- Severe thalassemia may
be treated with:
- Blood transfusions.
- Folic
acid.
- A splenectomy, which is surgical removal of the
spleen.
- A bone marrow transplant, in some severe cases.
Very rare forms of thalassemia may cause organ damage that can
result in death. This damage occurs when not enough oxygen reaches the organs.
Iron overload also may damage organs, especially the liver. The body can get
too much iron through repeated blood transfusions. If this happens, your doctor
may give you
chelating therapy. Or you may get medicine that binds
to the iron in your body and removes it through your urine or stool. You may
take this medicine as pill or have it pumped under your skin through a thin
tube.
Frequently Asked Questions
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