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Alpha thalassemia is a blood disorder that reduces the amount of hemoglobin that the body makes in red blood cells. Hemoglobin is an iron-rich protein in red blood cells that carries oxygen to cells throughout the body. There are 2 parts of this protein: alpha globin and beta globin.
Alpha thalassemia affects the amount of alpha globin made. It is caused by an inherited gene change (mutation) that is passed from parents to children.
Symptoms of alpha thalassemia happen because the body does not make enough hemoglobin to carry oxygen in the blood. How severe the symptoms are depends on the type of alpha thalassemia a person has and the severity of the disorder.
Alpha thalassemia is caused when the genes that control how the body makes hemoglobin change or are missing. The hemoglobin protein that is affected in alpha thalassemia is alpha globin.
Carriers are people who inherit hemoglobin genes that are changed or missing from 1 parent but inherit normal genes from the other parent. Carriers of alpha thalassemia usually do not have symptoms. But they can pass the affected genes on to their children. People who have moderate-to-severe forms of alpha thalassemia inherited affected hemoglobin genes from both parents.
Alpha globin is made by 4 copies of the alpha globin gene — 2 copies are on each strand of chromosome 16. Each person needs these 4 genes (2 from each parent) to make enough alpha globin for the body to make healthy hemoglobin. Different forms of alpha thalassemia occur if 1 or more of these genes are missing:
Alpha thalassemia is one of the most common blood disorders in the world. Anyone can have alpha thalassemia. Thousands of infants are born with the alpha thalassemia trait or hemoglobin H disease each year. But it is most common in people of Southeast Asian and African descent.
Because alpha thalassemia is inherited, family history and ancestry can help diagnose this blood disorder.
A parent with alpha globin-making genes that are changed or missing may have a child with a form of alpha thalassemia. Each child has a 25% (1 in 4) chance of inheriting 1, 2, or 3 missing genes. A baby born without all 4 genes is rare.
Tests to diagnose alpha thalassemia include:
Treatment for alpha thalassemia is based on the type and severity of the disorder.
Several treatments are used for moderate and severe forms of alpha thalassemia.
Blood transfusions are the main treatment for people with severe alpha thalassemia. This treatment provides healthy red blood cells with normal hemoglobin. Because red blood cells only live about 3 months, repeated transfusions may be needed to maintain a healthy supply of red blood cells.
People with hemoglobin H disease may need blood transfusions at certain times, such as during an infection, illness, or if symptoms of anemia occur.
Blood transfusions are a lifesaving treatment. They can help people with alpha thalassemia feel better, live longer, and have a better quality of life. But transfusions increase the risk of transmitted infections and viruses, such as hepatitis. Careful blood screening occurs in the United States, which makes this risk much lower.
Iron chelation therapy removes excess iron from the body. Excess iron is often caused by repeated blood transfusions, which are a treatment for severe alpha thalassemia. A buildup of iron in the blood (iron overload) can damage the heart, liver, and other parts of the body.
Medicines used for chelation therapy include:
A stem cell (bone marrow) transplant replaces the patient’s stem cells with healthy ones from a donor. Stem cells are the cells inside bone marrow that become red blood cells and other types of blood cells. A stem cell transplant is the only treatment that can cure alpha thalassemia, but the procedure has some risks. Only a small number of people with severe alpha thalassemia can be matched well with a donor. This treatment is rarely used for alpha thalassemia.
Researchers are working to find new treatments for alpha thalassemia.
Severe thalassemia (transfusion dependent thalassemia) can cause heart failure and death. Regular blood transfusions and iron chelation therapy or a successful stem cell transplant may improve the chance of survival.
Less severe forms of alpha thalassemia (silent carrier or alpha thalassemia trait) usually do not shorten a person’s lifespan.
Genetic counseling and prenatal screening may help people with a family history of alpha thalassemia that plan to have children.
St. Jude provides the highest quality of care for patients with alpha thalassemia:
More reasons to choose St. Jude for care include:
St. Jude offers clinical trials and research studies for children, teens, and young adults with blood disorders.
There are no open clinical trials for alpha thalassemia at this time.
Browse open clinical trialsPatients accepted to St. Jude must have a disease we treat and must be referred by a physician or other qualified medical professional. We accept most patients based on their ability to enroll in an open clinical trial.
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