Alpha thalassemia is a blood disorder caused by a shortage of alpha globin proteins in the hemoglobin molecules of red blood cells. This condition, also known as Hb Barts hydrops fetalis syndrome, can cause symptoms ranging from mild anemia to serious complications such as hemolytic anemia, jaundice, and enlarged spleen. Alternative names for alpha thalassemia include hydrops fetalis, fetal Hb Bart's disease, alpha thalassemia minor, alpha thalassemia major, and Hb H disease. While these terms refer to different presentations and degrees of severity of the disorder, they all describe a deficiency in the production of alpha globin chains in the hemoglobin molecule.