Thalassemias are a group of blood disorders that affect the way the body makes
hemoglobin. Hemoglobin is a protein found in red blood cells that carries oxygen throughout
the body. It's made up of alpha globin and beta globin.
The body contains more red blood cells than any other type of cell, and each has
a life span of about 4 months. Each day, the body produces new red blood cells to
replace those that die or are lost from the body.
With thalassemia, the red blood cells are destroyed at a faster rate, leading to
anemia, a condition that
can cause fatigue and other complications.
Thalassemias are inherited conditions — they're carried in the genes and
passed on from parents to children. People who are carriers of a thalassemia
gene show no thalassemia symptoms and might not know they're carriers. If both parents
are carriers, they can pass the disease to their kids. Thalassemias are not contagious.
While there are many different types of thalassemias, the main two are:
Beta thalassemia: when the body has a problem producing beta
When the gene that controls the production of either of these proteins is missing
or mutated, it results in that type of thalassemia.
About Beta Thalassemia
Beta thalassemia happens when the gene that controls the production of beta globin
is defective. Beta thalassemia can cause anemia ranging from mild to severe and is
more common in people of Mediterranean, African, and Southeast Asian descent.
A child can only get beta thalassemia by inheriting it from his or her parents.
Genes are "building blocks" that play an important role in determining physical traits
and many other things about us.
Humans are made up of trillions of cells that form the structure of our bodies
and carry out specialized jobs like taking nutrients from food and turning them into
energy. Red blood cells, which contain hemoglobin, deliver oxygen to all parts of
All cells have a nucleus at their center, which is kind of like the brain or "command
post" of the cell. The nucleus directs the cell, telling it to grow, mature, divide,
or die. The nucleus contains DNA (deoxyribonucleic acid), a long, spiral-shaped molecule
that stores the genes that determine hair color, eye color, whether or not a person
is right- or left-handed, and many more traits. DNA, along with genes and the information
they contain, is passed down from parents to their children during reproduction.
Each cell has many DNA molecules, but because cells are very small and DNA molecules
are long, the DNA is packaged very tightly in each cell. These packages of DNA are
called chromosomes, and each cell has 46 of them. Each package is arranged into 23
pairs — with one of each pair coming from the mother and one from the father.
When someone has beta thalassemia, there is a mutation in chromosome 11.
Beta globin is made on chromosome 11 (beta globin, along with alpha globin, is
one of the proteins that makes up hemoglobin). So, if one or both of the genes that
tells chromosome 11 to produce beta globin is altered, less beta globin is made. This
affects hemoglobin and decreases the ability of red blood cells to transport oxygen
around the body.
Types of Beta Thalassemia
There are three types of beta thalassemia, depending upon whether one or two beta
globin genes are mutated, and the severity of the mutations.
Beta thalassemia minor, or beta thalassemia trait,
happens when one of the beta globin genes is mutated. People with this condition typically
have very mild symptoms and require no treatment, but they can pass thalassemia on
to their children. Usually, they are mildly anemic and their red blood cells are smaller
Beta thalassemia major(Cooley's anemia) happens
when both of the beta globin genes are mutated (changed) and the mutations are severe.
This is the most severe form of beta thalassemia. Babies with beta thalassemia major
often seem healthy immediately after birth but start to develop symptoms within the
first 2 years of life. This condition causes severe symptoms with life-threatening
anemia that requires regular blood transfusions.
Beta thalassemia intermedia may also happen when both of the
beta globin genes are mutated, but the mutations are less severe than those that typically
cause beta thalassemia major. People with this condition usually have moderately severe
anemia and sometimes require regular blood transfusions.
Beta thalassemia major and intermedia can lead to serious complications, especially
if untreated. Complications of beta thalassemia major include:
Excess iron. Kids who have beta thalassemia can end up with too
much iron in their bodies, either from the disease itself or from getting repeated
blood transfusions. Excess iron can cause damage to the heart, liver, and endocrine
Bone deformities and broken bones. Beta thalassemia can cause
bone marrow to expand, making bones wider, thinner, and more brittle. This makes bones
more likely to break and can lead to abnormal bone structure, particularly in the
bones of the face and skull.
Enlarged spleen. The spleen helps fight off infections and filters
out unwanted materials, such as dead or damaged blood cells, from the body. Beta thalassemia
can cause red blood cells to die off at a faster rate, making the spleen work harder,
which makes it grow larger. A large spleen can make anemia worse and may need to be
removed if it gets too big.
Infections. Children with beta thalassemia have a higher risk
of infection, especially if they've had their spleens removed.
Slower growth rates. The anemia resulting from beta thalassemia
can cause children to grow more slowly and also can lead to delayed puberty.
The signs and symptoms of beta thalassemia vary depending on the type that a child
has. Most children with beta thalassemia trait have no symptoms. Those with beta thalassemia
major and intermedia may not show any symptoms at birth, but usually develop them
in the first 2 years of life.
Some of the more common symptoms of beta thalassemia include:
fatigue, weakness, or shortness of breath
a pale appearance or a yellow color to the skin (jaundice)
deformities of the facial bones
a swollen abdomen
Babies who begin to show symptoms of beta thalassemia after a few healthy months
may fail to grow normally (failure
to thrive); have trouble feeding; and have episodes of fever, diarrhea, and other
In most cases, beta thalassemia is diagnosed before a child's second birthday.
Children with beta thalassemia major may have a swollen abdomen or symptoms of anemia
or failure to thrive.
If the doctor suspects beta thalassemia, he or she will take a blood sample for
testing. Blood tests can reveal red blood cells that are pale, varied in shape and
size, and smaller than normal. They also can detect low red blood cell counts and
cells with an uneven distribution of hemoglobin, which causes them to look like a
bull's-eye when seen through a microscope.
Blood tests also can measure the amount of iron in the blood. Usually the diagnosis
is confirmed by a blood test called a hemoglobin electrophoresis and/or a DNA test
for abnormal hemoglobin genes.
If both parents are carriers of the beta thalassemia disorder, doctors can conduct
tests on a fetus before birth. This is done through either:
sampling, which takes place about 11 weeks into pregnancy and involves removing
a tiny piece of the placenta for testing
which is usually done about 16 weeks into the pregnancy and involves removing a sample
of the fluid that surrounds the fetus
If one parent carries a beta thalassemia gene and the other carries a different
gene that also affects beta globin, such as a sickle gene,
their child could have a significant blood disorder (such as a form of sickle cell
disease called sickle-beta thalassemia). Therefore, people who carry beta thalassemia
genes should seek genetic
counseling if they're considering having children so they can understand the risks.
The amount of treatment that beta thalassemia requires depends on how severe the
symptoms are. For most children with beta thalassemia trait, whose only symptom may
be mild anemia from time to time, no medical treatment will be necessary.
However, the blood counts in beta thalassemia trait look a lot like the blood counts
in iron deficiency anemia,
which is a very common disorder. It's important for doctors to know when children
have beta thalassemia trait so that they do not treat them with iron if it's not needed.
Doctors also might recommend a folic acid supplement for kids with moderate cases
of anemia to help boost production of new red blood cells.
Some children with moderate anemia may require an occasional blood
transfusion, particularly after surgery. Those with severe cases of beta thalassemia
major, on the other hand, may require regular blood transfusions their entire lives
to keep them healthy. During blood transfusions, they're given blood from donors with
matching blood types. Over time, this can cause a build-up of iron in the body, so
kids who receive frequent blood transfusions may have to take medications to remove
excess iron from their bodies.
Research into treating beta thalassemia with experimental gene therapies is ongoing.
But for now, it can only be cured by a procedure called a bone
marrow transplant (also called a stem cell transplant). Bone marrow, which is
found inside bones, produces blood cells. In a bone marrow transplant, children are
first given high doses of radiation or drugs to destroy the defective bone marrow.
The bone marrow is then replaced with cells from a compatible donor, usually a healthy
sibling or other relative. Bone marrow transplants carry many risks, so they usually
are done only in the most severe cases of thalassemia.
If your child has beta thalassemia, support groups are available to help your family
cope with the obstacles presented by the disease.