Thalassemia is a group of inherited blood disorders that reduce the body’s ability to make normal hemoglobin. Hemoglobin carries oxygen inside red blood cells. Depending on the genetic changes involved, thalassemia can cause no symptoms, mild anemia or severe lifelong disease.
Types
The two main groups are alpha thalassemia and beta thalassemia. Severity depends on which globin genes are affected and how much normal hemoglobin the body can produce. A person can carry a thalassemia trait and have few or no symptoms, while more severe forms may require regular specialist care.
Symptoms
- Fatigue, weakness or reduced exercise tolerance
- Pale skin or jaundice
- Shortness of breath
- Slow growth or delayed puberty in children with more severe disease
- Enlarged spleen or liver in some forms
- Bone changes in severe untreated disease
Inheritance
Thalassemia is inherited and is more common in people whose families come from the Mediterranean, Middle East, South Asia, Southeast Asia and parts of Africa. Carrier screening and genetic counseling can help people understand the chance of passing a clinically significant form to a child.
Diagnosis
Testing may include a complete blood count, examination of red blood cell indices, iron studies and hemoglobin analysis. Genetic testing can clarify the type in selected cases. Thalassemia trait can resemble iron deficiency, so iron supplements should not be started solely because red blood cells are small. Iron deficiency should be confirmed when suspected.
Treatment
People with a thalassemia trait often need no specific treatment. Moderate or severe disease may require regular blood transfusions, iron chelation to remove excess iron, monitoring of the heart, liver, bones and hormone function, and other specialist treatments. Stem cell transplantation can be curative for selected patients. Newer treatments are available for some forms and continue to evolve.
Living with thalassemia
Follow the individualized plan from the hematology team. Do not take iron supplements unless testing shows iron deficiency or a clinician specifically recommends them. Vaccinations, infection prevention, nutrition, physical activity and monitoring for complications should be tailored to the person’s condition and treatment.
When to seek medical care
Arrange medical assessment for unexplained persistent anemia, unusual fatigue, jaundice, poor growth or a family history of thalassemia. People receiving transfusions or specialist treatment should contact their care team for fever, worsening weakness, new shortness of breath or other significant changes. Seek emergency care for severe breathing difficulty, chest pain, collapse or other life-threatening symptoms.
This information is general and does not replace individual medical assessment, genetic counseling or treatment.
Sources and further reading
Last reviewed: 28 September 2026.