Thalassemia
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Thalassemia

(Mediterranean Anemia; Cooley's Anemia; Thalassemia Major; Thalassemia Minor)

Pronounced: Thal-uh-SEE-mee-uh

En Español (Spanish Version)

Definition

Thalassemia is an inherited disorder that leads to the decreased production and increased destruction of red blood cells. Hemoglobin, found in red blood cells, is responsible for carrying oxygen through the body to all of the organ systems. Low hemoglobin, due to loss of red blood cells, leads to anemia and the inability of the body to deliver oxygen and maintain normal functions.

Hemoglobin

© 2008 Nucleus Medical Art, Inc.

Thalassemias are named for the amino acid chain in the hemoglobin molecule that is affected. Amino acids are the building blocks of protein. Hemoglobin has two separate amino acid chains, alpha and beta. Thalassemias are also categorized by the number of genes that are absent or defective:

Alpha thalassemia—the alpha chain is affected

  • Silent carrier—one gene affected
  • Thalassemia trait—two genes affected
  • Hemoglobin H disease—three genes affected
  • Alpha hydrops fetalis—four genes affected

Beta thalassemia—the beta chain is affected

  • Thalassemia minor—one abnormal gene
  • Thalassemia major (Cooley's anemia)—two abnormal genes

Causes

An imbalance in the alpha and beta globin chains is caused by the inheritance of abnormal genes. There are four alpha genes and two beta genes.

The disease can develop if only one parent has abnormal genes. If only one gene is inherited, the person will be a carrier of the disease and have mild or no symptoms.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

  • Geographic location of ancestors, including:
    • Alpha thalassemias—Southeast Asia, Malaysia, and Southern China
    • Beta thalassemias—Africa, areas surrounding the Mediterranean Sea, and Southeast Asia
  • A family history of the disorder

Symptoms

Symptoms of thalassemia usually begin within 3-6 months of birth. Symptoms may include:

  • Anemia, which may be mild, moderate, or severe
  • Jaundice
  • Enlarged spleen
  • Fatigue (tiredness)
  • Listlessness
  • Reduced appetite
  • Enlarged and fragile bones, including:
    • Thickening and roughening of facial bones
    • Bones that break easily
    • Teeth that don't line up properly
  • Growth problems
  • Increased susceptibility to infection
  • Skin paler than usual
  • Hormone problems such as:
    • Delayed or absent puberty
    • Diabetes
    • Thyroid problems
  • Heart failure
  • Shortness of breath
  • Liver problems
  • Gallstones

Alpha thalassemia usually causes milder forms of the disease, with varying degrees of anemia. The most severe form of alpha thalassemia (alpha hydrops fetalis), which affects mainly individuals of Southeast Asian, Chinese, and Filipino ancestry, results in fetal or newborn death.

Beta thalassemia can be asymptomatic or be a mild form of disease, known as thalassemia intermedia. It causes milder anemia that rarely requires extensive medical care.

Beta thalassemia major, also known as Cooley's anemia, is a serious disease that requires regular blood transfusions and extensive medical care. Those with thalassemia major usually show symptoms within the first two years of life. They become pale and listless and have poor appetites. They grow slowly and often develop jaundice.

Without treatment, the spleen, liver, and heart soon become greatly enlarged. Bones become thin and brittle. Abnormal deposition of iron ( secondary hemochromatosis ) in body organs, including heart, liver, and pancreas, can lead to organ failure. Heart failure and infection are the leading causes of death among children with untreated thalassemia major.

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. Blood tests may include:

  • Complete blood count
  • Blood smear
  • Hemoglobin electrophoresis
  • Quantitative hemoglobin analysis
  • Iron levels

Treatment

Treatment may include:

Blood Transfusions

You may require blood transfusions to replace abnormal red blood cells with healthy new ones.

Iron Chelation Therapy

Excess iron can accumulate in the body after repeated blood transfusions. Too much iron can damage the heart, liver, and other vital organs (secondary hemochromatosis). A drug call deferoxamine (Desferal) can be given to bind to excess iron in the body and carry it out through the urine. This drug is given through the skin or by vein using a small infusion pump.

Splenectomy

In some cases, surgically removing the spleen may help reduce the number of blood transfusions that are needed.

Bone Marrow Transplant

Healthy stem cells from a donor's bone marrow are injected into your vein. The new cells travel through the bloodstream to the bone cavities, where they can produce new blood cells, including red blood cells. This is usually only done in severe cases. A compatible sibling donor is required.

Prevention

Blood tests and family genetic studies can show whether an individual has thalassemia or is a carrier. A genetic counselor can detail the family background, discuss risks, and give you information on available testing.

RESOURCES:

Northern California Comprehensive Thalassemia Center
http://www.thalassemia.com

National Heart, Lung, and Blood Institute
http://www.nhlbi.nih.gov

CANADIAN RESOURCES:

Canadian Hemophiliac Society
http://www.hemophilia.ca

The Thalassemia foundation of Canada
http://www.thalassemia.ca

References:

Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov .

Northern California Comprehensive Thalassemia Center website. Available at: http://www.thalassemia.com .



Last reviewed November 2007 by Mark A. Best, MD, MPH, MBA, FCAP, FASCP

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.


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