People with mild to severe forms of thalassemia may experience anemia that causes symptoms such as fatigue, shortness of breath or heart palpitations. Severe anemia can affect the growth of children and delay their sexual development. In addition, patients may experience a yellowing of the skin known as jaundice, which results from the destruction of red blood cells. The liver and spleen may become enlarged.

Anemia also causes bone marrow to work harder to create more red blood cells in the body. This bone marrow hyperactivity can lead to enlargement of bones such as the cheekbones and those of the forehead. Abnormalities in the ability of the liver and gallbladder to produce bile can lead to gallstones. Patients also may have protruding abdomens and dark urine.

People who have thalassemia trait rather than thalassemia itself may experience mild anemia, which in turn can cause mild fatigue.