Thalassemia consists of a group of inherited diseases of the blood. About 100,000 babies worldwide are born with severe forms of the disease each year. Thalassemia occurs most frequently in people of Italian, Greek, Middle Eastern, Southern Asian and African ancestry.
What Are the Different Kinds of Thalassemia?
Thalassemia includes a number of different forms of anemia (red blood cell deficiency). The two main types are called alpha and beta thalassemias, depending on which part of an oxygen-carrying protein (called hemoglobin) is lacking in the red blood cells.
The most severe form of alpha thalassemia, which affects mainly individuals of Southeast Asian, Chinese and Filipino ancestry, results in fetal or newborn death. Most individuals with alpha thalassemia have milder forms of the disease, with varying degrees of anemia.
The remainder of this information sheet focuses on beta thalassemias, which range from very severe to having no effect on health.
- Thalassemia major, the most severe form, is also called Cooley's anemia, named after the doctor who first described it in 1925.
- Thalassemia intermedia is a mild Cooley's anemia.
- Thalassemia minor (also called thalassemia trait) may cause no symptoms, but changes in the blood do occur.
How Does Thalassemia Affect a Child?
Most children with thalassemia major appear healthy at birth, but during the first year or two of life they become pale, listless and fussy, and have a poor appetite. They grow slowly and often develop jaundice (yellowing of the skin).
Without treatment, the spleen, liver, and heart soon become greatly enlarged. Bones become thin and brittle; face bones become distorted, and children with thalassemia often look alike. Heart failure and infection are the leading causes of death among children with untreated thalassemia major.
Children with thalassemia intermedia may develop some of the same complications, although in most cases, the course of the disease is mild for the first two decades of life.
What Is the Treatment?
The use of frequent blood transfusions and antibiotics has improved the outlook for children with thalassemia major. Children with thalassemia intermedia usually do not require transfusions, although they may be recommended if complications start to develop.
When children with thalassemia major are treated with frequent transfusions (generally every 3 to 4 weeks) aimed at keeping their hemoglobin level near normal, many of the complications of thalassemia can be prevented. This form of treatment, referred to as "hypertransfusion," enhances the child's growth and well-being, and usually prevents heart failure and bone deformities.
Unfortunately, repeated blood transfusions lead to a buildup of iron in the body, which can damage the heart, liver and other organs. A drug referred to as an iron chelator, an iron binding agent, can help rid the body of excess iron, preventing or delaying problems related to iron overload. The drug is usually administered daily via a mechanical pump that pumps the drug underneath the skin while the child is sleeping.
Children with thalassemia major who are treated with frequent blood transfusions and iron chelation live 20 to 30 years or longer. Since intensive chelation treatment was introduced only in the 1960s, continuing studies may show that treated individuals are living even longer.
Thalassemia has been cured using bone marrow transplants. However, this form of treatment is possible only for a small minority of patients who have a suitable bone marrow donor, and the transplant procedure is still risky and can result in death.
How Is the Disease Transmitted?
All forms of thalassemia are transmitted only through heredity. It cannot be caught from another child who has it. The disease is passed on through parents who carry the thalassemia gene in their cells. 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.
When two carriers become parents, there is a one-in-four chance that any child they have will inherit a thalassemia gene from each parent and have a severe form of the disease. There is a two-in-four chance that the child will inherit one of each kind of gene and become a carrier like its parents; and a one-in-four chance that the child will inherit two normal genes from its parents and be completely free of the disease or carrier state. These odds are the same for each pregnancy when both parents are carriers.
Is There a Test for Thalassemia?
Yes. Blood tests and family genetic studies can show whether an individual has thalassemia or is a carrier. In addition, prenatal testing using chorionic villus sampling (CVS) or amniocentesis can detect or rule out thalassemia in the fetus. Early diagnosis is important so that treatment can prevent as many complications as possible.
Can Thalassemia Be Prevented?
The disease can't be prevented at this time, but a program of health education, testing for the trait, genetic counseling, and prenatal diagnosis can provide families with full medical information to help them have healthy children.
People who think they may have or carry thalassemia can go to a genetic services center or clinic for the latest information and for testing. Individuals can be tested to find out if they are carriers. Genetic counselors then can help them make plans about future families.
What Research on Thalassemia Is Taking Place?
Scientists are working on better ways to remove excess iron from the body in order to prevent or delay iron overload. They are developing and testing the effectiveness of oral iron-chelating drugs, which could greatly simplify treatment of this disease. March of Dimes grantees are among the many scientists seeking to develop an effective form of gene therapy that may someday offer a cure for thalassemia. Gene therapy may involve inserting a normal beta globin gene (the gene that is abnormal in this disease) into the patient's stem cells, the immature bone marrow cells that are the precursors of all other cells in the blood. Another form of gene therapy may involve using drugs or other methods to reactivate the patient's genes for fetal hemoglobin. All humans produce a fetal form of hemoglobin before birth; after birth, natural genetic switches "turn off" production of fetal hemoglobin and "turn on" production of adult hemoglobin. Scientists are seeking ways to activate these genetic switches so that they can make the blood cells of patients with thalassemia produce more fetal hemoglobin to compensate for their deficiency of adult hemoglobin. Initial studies of rare individuals with genetic traits that allow them to produce only fetal hemoglobin show that they are generally healthy, demonstrating that fetal hemoglobin can be a fine substitute for adult hemoglobin.
In addition, improved bone marrow transplantation methods may lead to wider use of the technique as a treatment for thalassemia. Bone marrow transplants have cured some cases of thalassemia but they are not widely used for the reasons discussed earlier.
For further information about thalassemia, contact:
Cooley's Anemia Foundation, Inc.
129-09 26th Avenue
Flushing, NY 11354
(718) 321-2873
En Español: Click here to view this fact sheet in Spanish.
To order multiple copies of this fact sheet:
Call: (800)-367-6630
