Thalassemias are inherited blood diseases that cause defective or reduced production of hemoglobin, the molecule found inside red blood cells that carries oxygen throughout the body. Reduced levels of hemoglobin keep the body from producing adequate levels of healthy red blood cells, a condition known as anemia. Thalassemias are a common form of genetic disorder.

Patients with anemia have less oxygen delivered to the tissues, resulting in a lack of energy. Other symptoms include fatigue, jaundice (yellowing of skin and eyes), shortness of breath, and delayed growth and development in children. Heart failure may develop due to severe anemia. The severity of a thalassemia can vary significantly from patient to patient. Some patients may experience few symptoms, but others may require hospitalization or ongoing treatments.

In recent years, experts have made significant progress in treating thalassemias. As a result, patients with thalassemias now tend to have longer and fuller lives than was previously the case. Patients with severe disease who are diagnosed and treated early may live into their 30s, 40s or beyond. People with less severe forms of the disease, or who are genetic carriers, have a normal life expectancy.