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Alpha thalassemia

Alpha thalassemia

Reviewed August 2009

What is alpha thalassemia?

Alpha thalassemia is a blood disorder that reduces the production of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen to cells throughout the body.

In people with the characteristic features of alpha thalassemia, a reduction in the amount of hemoglobin prevents enough oxygen from reaching the body's tissues. Affected individuals also have a shortage of red blood cells (anemia), which can cause pale skin, weakness, fatigue, and more serious complications.

Two types of alpha thalassemia can cause health problems. The more severe type is known as hemoglobin Bart hydrops fetalis syndrome or Hb Bart syndrome. The milder form is called HbH disease.

Hb Bart syndrome is characterized by hydrops fetalis, a condition in which excess fluid builds up in the body before birth. Additional signs and symptoms can include severe anemia, an enlarged liver and spleen (hepatosplenomegaly), heart defects, and abnormalities of the urinary system or genitalia. As a result of these serious health problems, most babies with this condition are stillborn or die soon after birth. Hb Bart syndrome can also cause serious complications for women during pregnancy, including dangerously high blood pressure with swelling (preeclampsia), premature delivery, and abnormal bleeding.

HbH disease causes mild to moderate anemia, hepatosplenomegaly, and yellowing of the eyes and skin (jaundice). Some affected individuals also have bone changes such as overgrowth of the upper jaw and an unusually prominent forehead. The features of HbH disease usually appear in early childhood, and affected individuals typically live into adulthood.

How common is alpha thalassemia?

Alpha thalassemia is a fairly common blood disorder worldwide. Thousands of infants with Hb Bart syndrome and HbH disease are born each year, particularly in Southeast Asia. Alpha thalassemia also occurs frequently in people from Mediterranean countries, North Africa, the Middle East, India, and Central Asia.

What genes are related to alpha thalassemia?





Read more about the HBA1 and HBA2 genes.

How do people inherit alpha thalassemia?


Where can I find information about diagnosis or management of alpha thalassemia?

These resources address the diagnosis or management of alpha thalassemia and may include treatment providers.

You might also find information on the diagnosis or management of alpha thalassemia in Educational resources and Patient support.



Where can I find additional information about alpha thalassemia?

You may find the following resources about alpha thalassemia helpful. These materials are written for the general public.


What other names do people use for alpha thalassemia?

  • alpha-thalassemia
  • α-thalassemia


What if I still have specific questions about alpha thalassemia?

Where can I find general information about genetic conditions?

What glossary definitions help with understanding alpha thalassemia?

allele ; anemia ; cell ; gene ; genitalia ; Hb ; hemoglobin ; hepatosplenomegaly ; hydrops fetalis ; inheritance ; inherited ; jaundice ; newborn screening ; oxygen ; protein ; screening ; substitution ; subunit ; syndrome ; thalassemia ; trait ; upper jaw


See also Understanding Medical Terminology.

References (6 links)



Reviewed: August 2009
Published: December 22, 2014