• Thalassemia

    The thalassemias are a group of inherited blood disorders in which the genes that produce hemoglobin, the protein in red blood cells that carries oxygen from the lungs to all parts of the body, are broken. As a result, the red blood cells do not contain enough hemoglobin, causing anemia that can range from mild to life threatening. Thalassemia can come in different forms depending on the genetic mutations causing it. The transfusion-dependent form, also called thalassemia major or Cooley’s Anemia, requires lifelong follow-up care and regular blood transfusions. Some other forms are more readily managed and may require little or no treatment.

    Thalassemia Treatment at Dana-Farber/Boston Children’s

    At the Dana-Farber/Boston Children’s Thalassemia Program, our experts provide comprehensive care for children and adults with all forms of thalassemia. For many appointments and certain procedures, your child also can receive care at one of our satellite offices. Treatment for thalassemia depends on the subtype of the disorder, but may include:

    • blood transfusions for anemia, based on severity
    • regular and comprehensive monitoring for complications of thalassemia and of treatments
    • iron chelation therapy, to remove excess iron from the body
    • for certain cases, stem cell transplantation to replace the blood-forming stem cells with the defective hemoglobin gene(s)

    Learn more about the thalassemias and treatment options below.

    What are the thalassemias?

    The thalassemias are a group of inherited blood disorders in which the genes that produce hemoglobin, the protein in red blood cells that carries oxygen from the lungs to all parts of the body, are broken.

    Hemoglobin is made up of four parts—two alpha globin proteins and two beta globin proteins—each produced according to the instructions carried in different genes. Thalassemia results when one or more of these genes is defective or missing. Globin proteins work in connection with heme and iron to carry oxygen.

    Doctors classify forms of thalassemias based on the globin genes involved:

    • Alpha-thalassemias. These conditions arise due to mutations in or loss of one or both of a patient's alpha globin genes. One of these conditions, called hemoglobin H alpha-thalassemia or three-alpha thalassemia, is common in Southern China and Southeast Asia.
    • Beta-thalassemias. These thalassemias arise from mutations in or loss of the beta globin genes. A particular beta-thalassemia disorder called hemoglobin E/beta0 thalassemia, is more common in children of Southeast Asian descent, and results from two separate genetic defects: a defective type of hemoglobin called hemoglobin E, and a defective beta globin gene.

    The defective genes that cause thalassemia are relatively common, especially in people of South Asian, African and Mediterranean descent. However, thalassemia occurs in many populations around the world.

    The thalassemias can also be classified by clinical severity:

    • Thalassemia trait, and silent carriers. Children with thalassemia trait (also called thalassemia minor) have two alpha globin genes or one beta globin gene missing or damaged. Those that are “silent carriers” have one missing or damaged alpha globin gene. These children do not experience symptoms (except mild anemia in some cases of thalassemia trait), and they do not require treatment. People with thalassemia trait are at high risk of having children with some form of thalassemia. Several hundred million people around the world have thalassemia trait. It is one of the most common genetic traits worldwide.  Potential carriers are identified by small red blood cells or by family history or newborn screening. It is important for carriers to know which of their genes are affected (alpha or beta) and seek genetic counseling for family planning.
    • Non-transfusion dependent thalassemia. In children with non-transfusion dependent thalassemia (formerly called thalassemia intermedia), one or both of the beta globin genes are not working properly. They have mild to severe anemia and can be diagnosed early in childhood or later in life. They may need blood transfusions during pregnancy or when very sick. Patients with non-transfusion dependent thalassemia may initially be misdiagnosed with thalassemia trait, but are typically somewhat more anemic and may even require transfusions from time to time.
    • Transfusion dependent thalassemia. Children with transfusion dependent thalassemia (formerly called thalassemia major) need ongoing medical care, including blood transfusions to alleviate severe anemia and chelation therapy to remove excess iron from the blood.

    Transfusion dependent thalassemia can be further divided into:

    • Transfusion dependent alpha-thalassemia. This is the most serious and most rare form of thalassemia. In patients with transfusion dependent alpha thalassemia, all four alpha and beta globin genes are missing. Children with this form of thalassemia may be treated with blood transfusions in the womb if identified early enough. If untreated, however, it often leads to miscarriage or death of the baby shortly after birth. Babies who survive require lifelong blood transfusions or stem cell transplant and extensive medical care. Some patients with rare types of hemoglobin H disease may also require lifelong transfusions.
    • Transfusion dependent beta-thalassemia. Also called Cooley’s anemia, in this form of thalassemia neither beta globin gene works properly. The symptoms of transfusion dependent beta thalassemia, including severe anemia, appear during the first year of life. Patients with this form of thalassemia require monthly blood transfusions, as well as chelation therapy to remove excess iron that builds up in the body from the frequent transfusions.

    The severity of the disease depends on the type of thalassemia, ranging from no treatment to lifelong care with frequent blood transfusions and ongoing chelation therapy to remove the excess iron that builds up in the blood from these transfusions.

    What are the symptoms of the thalassemias?

    Symptoms of thalassemia depend on the clinical severity of the disease and the therapies employed to treat it. Each child may experience symptoms differently. Patients with thalassemia trait generally do not experience any symptoms.

    Transfusion dependent thalassemia

    The primary signs and symptoms of Cooley’s anemia in infancy, before diagnosis, are those of severe anemia. Later in childhood and adulthood, transfusion dependent thalassemia symptoms are generally the result of iron overload, a byproduct of the frequent blood transfusions patients with this form of thalassemia require.

    Patients with transfusion dependent thalassemia do not typically experience severe anemia once they have started receiving regular transfusion. Without these transfusions, however, they can develop life-threatening anemia.

    Symptoms of iron overload may include:

    • chronic fatigue
    • liver disease
    • abdominal pain
    • heart problems
    • joint pain

    Non-transfusion dependent thalassemia

    The most common symptoms of non-transfusion dependent thalassemia are related to anemia:

    • pale skin, lips, hands or under the eyelids
    • increased heart rate (tachycardia)
    • breathlessness, or difficulty catching a breath (dyspnea)
    • lack of energy, or tiring easily (fatigue)
    • dizziness or vertigo, especially upon standing
    • headache
    • irritability
    • irregular menstruation cycles
    • absent or delayed menstruation (amenorrhea)
    • slow or delayed growth and development
    • bony overgrowth or deformities
    • an increased risk of bone fractures

    How is thalassemia diagnosed?

    A diagnosis of thalassemia is made after tests to discover which type of thalassemia a child might have. Those tests include:

    • A complete blood count (CBC) measures the number of red blood cells and their concentration of hemoglobin, as well as many other red cell features. Hematologists evaluate the blood under a microscope as well.
    • hemoglobin electrophoresis
    • Genetic tests are used to identify specific genetic defects that cause thalassemia.

    After those tests are complete, doctors will be able to outline the best treatment options.

    How is thalassemia treated?

    Treating children with thalassemia is a multidisciplinary effort, including specialists in hematology and transfusion medicine as well as cardiologists, endocrinologists, gastroenterologists, audiologists, ophthalmologists, infectious disease specialists, geneticists and genetic counselors as necessary.

    Treatment for thalassemia depends on the severity of the disorder. If your child has transfusion dependent thalassemia, she will require life-long, ongoing medical care, which may include:

    • Blood transfusions from healthy donors, which can alleviate anemia. How often transfusions are necessary will depend on the type of thalassemia. Because of transfusions bring with them the risk of iron overload (which can cause organ damage), children receiving frequent transfusions should be monitored carefully. We use specialized magnetic resonance imaging technologies such as FerriScan and T2* to look for signs of iron overload.
    • Iron chelation therapy, which reduces the amount of iron in the body and prevents or treats iron overload.
    • Stem cell transplantation to replace the blood-forming stem cells with the defective hemoglobin gene(s). Stem cell transplantation can cure thalassemia by replacing defective blood-forming stem cells with healthy stem cells from a donor. Unfortunately it may not be an option for everyone. The success of a transplant depends on many factors, such as how close the match is between child and donor (matched siblings are best; if your child has a sibling, there is a 1 in 4 chance they will be a match) and the patient's age. The degree to which your child's bone marrow has failed also factors into the discussion whether to pursue a transplant. The decision of whether to proceed with a stem cell transplant should be discussed with your child’s hematologist and a stem cell transplant team.

    In general, children with non-transfusion dependent thalassemia experience less severe symptoms. They need regular medical follow-up, but may not require frequent blood transfusions.

    What is the latest thalassemia research?

    Dana-Farber/Boston Children's is involved in a number of research initiatives aimed at improving thalassemia care including:

    • investigating the effectiveness of new oral iron chelators, drugs that remove excess iron from the body
    • improving existing chelation therapies and investigating new ones
    • using stem cell transplants to cure patients with transfusion dependent thalassemia
    • developing new ways to assess iron levels in the body
    • understanding how to use gene therapy to force red blood cells to make a form of hemoglobin called fetal hemoglobin, which our cells make until birth and which is not affected by the genetic defects that cause thalassemia

    Clinical Trials

    For many children with rare or hard-to-treat conditions, clinical trials provide new options.

    Contact us: If you’re not sure which clinical trials might be right for your child, email us at clinicaltrials@danafarberbostonchildrens.org. We can help you navigate your options.

    What’s the long-term outlook for children with thalassemia?

    In the past, patients with transfusion dependent thalassemia had a significantly reduced life expectancy. Today, however, thanks to blood transfusion therapy and effective iron chelators, the life expectancy for children with severe thalassemia is constantly improving. Once rare, survival to older adulthood is becoming the norm.
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