People with thalassemia have an inherited blood disorder that causes
mild or severe anemia (uh-NEE-me-uh). The anemia is due to reduced
hemoglobin (he-mo-GLOBE-in) and fewer red blood cells than normal.
Hemoglobin is the protein in red blood cells that carries oxygen to
all parts of the body.
In people with Thalassemia, the genes that code for hemoglobin are
missing or variant (different than the normal genes). Severe forms
of thalassemia are usually diagnosed in early childhood and are
lifelong conditions.
The two main types of thalassemia, alpha and beta, are named for the
two protein chains that make up normal hemoglobin. The genes for
each type of thalassemia are passed from parents to their children.
There are mild and severe forms of the disease, the latter often
called Cooley's anemia. Cooley's anemia is the most common severe
form of thalassemia seen in the U.S.
Thalassemia Major
Thalassemia Minor.
Alpha thalassemia: occurs when one or more of the four genes
needed for making the alpha globin chain of hemoglobin are variant
or missing. Moderate to severe anemia results when more than two
genes are affected. Alpha thalassemia major can result in
miscarriages.
Beta thalassemia: occurs when one or both of the two genes
needed for making the beta globin chain of hemoglobin are variant.
The severity of illness depends on whether one or both genes are
affected, and the nature of the abnormality. If both genes are
affected, anemia can range from moderate to severe.
OTHER
NAMES FOR THALASSEMIA
Alpha Thalassemias
Alpha thalassemia "silent carrier"
Mild alpha thalassemia, also called alpha
thalassemia minor or alpha thalassemia trait
Hemoglobin H disease
Hydrops fetalis, or alpha thalassemia major
Beta Thalassemias
Beta thalassemia minor, also called thalassemia
minor or thalassemia trait
Beta thalassemia intermedia, also called
thalassemia intermedia or mild Cooley's anemia
Beta thalassemia major, also called thalassemia
major or Cooley's anemia
Mediterranean anemia
Cooley's anemia sometimes is used to refer to
any type of thalassemia that requires treatment with regular blood
transfusions.
WHAT
CAUSES THALASSEMIA?
Thalassemia is caused by variant or missing genes that affect how
the body makes hemoglobin. Hemoglobin is the protein in red blood
cells that carries oxygen. People with thalassemia make less
hemoglobin and fewer circulating red blood cells than normal, which
results in mild or severe anemia.
There are many possible combinations of variant genes that cause the
various types of thalassemia. Thalassemia is always inherited
(passed from parents to children). People with moderate to severe
forms of thalassemia received variant genes from both parents. A
person who inherits a thalassemia gene or genes from one parent and
normal genes from the other parent is a carrier (thalassemia trait).
Carriers often have no signs of illness other than mild anemia, but
they can pass the variant genes on to their children.
Hemoglobin includes two kinds of protein chains called alpha globin
chains and beta globin chains. If the problem is with the alpha
globin part of hemoglobin, the disorder is alpha thalassemia. If the
problem is with the beta globin part, it is called beta thalassemia.
There are both mild and severe forms of alpha and beta thalassemia.
Severe beta thalassemia is often called Cooley's anemia.
ALPHA THALASSEMIA
There are four genes involved in making the alpha globin part of
hemoglobin--two from each parent. Alpha thalassemia occurs when one
or more of these genes are variant or missing.
People with only one gene affected are called
"silent carriers" and have no sign of illness.
People with two genes affected (alpha
thalassemia trait, or alpha thalassemia minor) have mild anemia and
are considered carriers.
People with three genes affected (hemoglobin H
disease) have moderate to severe anemia.
Until recently, babies with all four genes
affected (alpha thalassemia major, or hydrops fetalis) could not
survive and usually died before birth. Today, many of these babies
can survive with treatment.
If two people with alpha thalassemia trait
(carriers) have a child, the baby could have a mild or severe form
of alpha thalassemia or could be healthy.
BETA THALASSEMIA
There are two genes involved in making the beta globin part of
hemoglobin--one from each parent. Beta thalassemia occurs when one
or both of the two genes are variant.
If one gene is affected, a person is a carrier
and has mild anemia. This condition is called beta thalassemia
trait, or beta thalassemia minor.
If both genes are variant, a person may have
moderate anemia (beta thalassemia intermedia, or mild Cooley's
anemia) or severe anemia (beta thalassemia major, or Cooley's
anemia).
If two people with beta thalassemia trait
(carriers) have a baby, one of three things can happen:
The baby could receive two normal genes (one
from each parent) and have normal blood (1 in 4 chance).
The baby could receive one normal gene from one
parent, and one variant gene from the other parent, and have
thalassemia trait (2 in 4 chance).
The baby could receive two thalassemia genes
(one from each parent) and have a moderate to severe form of the
disease (1 in 4 chance).
Who Gets Thalassemia?
Alpha thalassemias mostly affect people of
Southeast Asian, Indian, Chinese, or Filipino origin or ancestry.
Beta thalassemias affect people of
Mediterranean origin or ancestry (Greek, Italian, Middle Eastern)
and people of Asian and African descent.
Thalassemia affects both males and females.
Thalassemia is passed from parents to children
through their genes.
WHAT ARE THE SIGNS AND
SYMPTOMS OF THALASSEMIA?
The symptoms of thalassemia depend on the type and severity of the
disease. Symptoms occur when not enough oxygen gets to various parts
of the body due to low hemoglobin and a shortage of red blood cells
in the blood (anemia).
"Silent carriers" and persons with alpha thalassemia trait or beta
thalassemia trait (also called carriers) usually have no symptoms.
Those with alpha or beta thalassemia trait often have mild anemia
that may be found by a blood test.
In more severe types of thalassemia such as Cooley's anemia, signs
of the severe anemia are seen in early childhood and may include:
Fatigue (feeling tired) and weakness
Pale skin or jaundice (yellowing of the skin)
Protruding abdomen with enlarged spleen and
liver
Dark urine
Abnormal facial bones and poor growth.
Babies with the most severe type of alpha
thalassemia (hydrops fetalis) die before birth or soon after birth.
HOW IS THALASSEMIA DIAGNOSED?
THALASSEMIA IS DIAGNOSED USING BLOOD TESTS, INCLUDING A COMPLETE
BLOOD COUNTS (CBC) AND SPECIAL HEMOGLOBIN STUDIES.
A complete blood count provides information
about the amount of hemoglobin and the different kinds of blood
cells, such as red blood cells, in a sample of blood. People with
thalassemia have less hemoglobin than normal and fewer red blood
cells than normal in their blood. Carriers of the trait may have
slightly small red blood cells as their only sign.
Hemoglobin studies measure the types of
hemoglobin in a blood sample.
Cooley's anemia is usually diagnosed in early
childhood because of signs and symptoms and severe anemia. Some
people with milder forms of thalassemia may be diagnosed after a
routine blood test shows that they have anemia. Doctors suspect
thalassemia if a child has anemia and is a member of an ethnic group
that is at risk for thalassemia.
To distinguish anemia caused by iron deficiency from anemia caused
by thalassemia, tests of the amount of iron in the blood may be
done.
Family genetic studies are also helpful in diagnosing thalassemia.
This involves taking a family history and doing blood tests on
family members.
Prenatal testing can determine if an unborn baby has thalassemia and
how severe it is likely to be.
HOW
IS THALASSEMIA TREATED?
Treatment for thalassemia depends on the type and severity of the
disease.
People who are carriers (thalassemia trait)
usually have no symptoms and need no treatment.
Those with moderate forms of thalassemia (for
example, thalassemia intermedia) may need blood transfusions
occasionally.
Those with severe thalassemia have a serious
and life-threatening illness. They are treated with regular blood
transfusions, iron chelation therapy, and bone marrow transplants.
Without treatment, children with severe thalassemia do not live
beyond early childhood.
BLOOD
TRANSFUSIONS
Severe forms of thalassemia are treated by regular blood
transfusions. A blood transfusion provides blood containing normal
red blood cells from healthy donors, given through a needle in a
vein. In thalassemia treatment, blood transfusions are done on a
schedule (often every 2-4 weeks) to keep hemoglobin and red blood
cell numbers at normal levels. Transfusion therapy can allow a
person with severe thalassemia to feel better, enjoy normal
activities, and live longer.
Transfusion therapy, while lifesaving, is expensive and carries a
risk of transmission of viral and bacterial diseases (for example,
hepatitis). It also leads to excess iron in the blood (iron
overload), which can damage the liver, heart, and other parts of the
body. To prevent damage, iron chelation therapy is needed to remove
excess iron from the body.
IRON CHELATIOIN (ke-LAY-shun) THERAPY
Iron chelation therapy uses medicine to remove the excess iron that
builds up in the body when a person has regular blood transfusions.
If the iron is not removed, it damages body organs such as the heart
and liver.
The medicine, deferoxamine (deh-fer-ROX-uh-meen), works best when
given slowly under the skin, usually with a small portable pump
overnight. This therapy is demanding and sometimes mildly painful,
so some people stop chelation therapy. A pill form of iron chelation
therapy is being studied.
People who have iron overload should not take vitamins or other
supplements that contain iron.
SURGERY
Surgery may be needed if body organs such as the spleen or gall
bladder are affected. For example, if the spleen becomes inflamed
and enlarged, it may be removed. If gallstones develop, the gall
bladder may be removed.
BONE MARROW OR STEM CELL TRANSPLANTS
Bone marrow or stem cell transplants have been used successfully in
some children with severe thalassemia. This is a risky procedure,
but it offers a cure for those children who qualify.
OTHER TREATMENTS
People with severe thalassemia are more likely to get infections
that can worsen their anemia. They should get an annual flu shot and
the pneumonia vaccine to help prevent infections.
Folic acid is a B vitamin that helps build red blood cells. People
with thalassemia should take folic acid supplements.
Researchers are also studying other treatments, including:
Gene therapy. Someday, it may be possible to
cure an unborn child with thalassemia by inserting a normal gene
into the child's stem cells.
Fetal hemoglobin. Researchers are studying ways
to enhance production of fetal hemoglobin in people with
thalassemia. Fetal hemoglobin is the type of hemoglobin made by the
body before birth. After birth, the body usually switches from
making fetal hemoglobin to the adult form of hemoglobin. Some
children have a gene variant that prevents the switch, and their
continuing production of fetal hemoglobin lessens the severity of
their illness.
CAN
THALASSEMIA BE PREVENTED?
Although thalassemia cannot be prevented, it can be identified
before birth by prenatal diagnosis.
People who have or believe that they may carry the thalassemia genes
can receive genetic counseling to avoid passing the disorder to
their children.
LIVING WITH
THALASSEMIA
If you have moderate or severe thalassemia, you need to take care of
your health.
Follow your treatment plan. See your doctor
regularly for checkups and treatment.
If you must have regular blood transfusions and
iron chelation therapy, it is important to continue with treatment
as recommended.
If you have regular blood transfusions, you
should avoid taking vitamins or other supplements containing iron.
Maintain a healthy diet. Your doctor may also
give you a folic acid (a B vitamin) supplement every day to help
your body make new red blood cells.
Get a flu shot every year and the pneumococcal
vaccine to prevent infections.
FREQUENTLY
ASKED QUESTIONS?
1. How common is Cooley's anemia?
ANS:
Cooley's anemia, or beta thalassemia major, is a rare condition. A
survey in 1993 found 518 Cooley's anemia patients in the U.S, most
with the severe form of the illness, but there may be more.
2. What is iron-deficiency anemia, and how is it different from the
anemia in thalassemia?
ANS: Both kinds of anemia occur due to a problem with hemoglobin, the
part of red blood cells that carries oxygen to all parts of the
body. Iron deficiency anemia occurs because the body doesn't have
enough iron for making hemoglobin. The anemia in thalassemia occurs
not because of a lack of iron, but because of a problem with another
component of hemoglobin--either the alpha globin chain or the beta
globin chain. Iron supplements do nothing to improve the anemia of
thalassemia, because missing iron is not the problem.
3. How long do people with severe thalassemia live?
ANS: The length of life depends on how severe the disorder is, how soon
treatment begins, and how successful the treatment is. People with
severe thalassemia who are able to continue therapy successfully may
live into their 30s, 40s, and beyond.
4. What is fetal hemoglobin?
ANS: Fetal hemoglobin is a type of hemoglobin produced by unborn babies
and infants. At some point soon after birth, the body switches to
making the adult type of hemoglobin. In some children with
thalassemia, a variant gene allows them to continue making some
fetal hemoglobin. This means their anemia and symptoms are less
severe than in people who stop making fetal hemoglobin. Researchers
are testing ways to enhance fetal hemoglobin production after birth.
5. Does a person with thalassemia intermedia need blood
transfusions?
ANS: Because the severity of thalassemia intermedia (sometimes called
mild Cooley's anemia) varies from person to person, the need for
treatment also varies. Some people with thalassemia intermedia need
occasional transfusions, such as when they are experiencing stress
due to an infection. If a person with thalassemia intermedia worsens
and needs regular transfusions, he or she is no longer considered to
have thalassemia intermedia. Instead, the person is said to have
thalassemia major, or Cooley's anemia.
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