MedGen

Beta-thalassemia (BT) intermedia is a form of BT (see this term) characterized by mild to moderate anemia which does not or only occasionally requires transfusion. [from ORDO]

Beta-thalassemia (ß-thalassemia) is characterized by reduced synthesis of the hemoglobin subunit beta (hemoglobin beta chain) that results in microcytic hypochromic anemia, an abnormal peripheral blood smear with nucleated red blood cells, and reduced amounts of hemoglobin A (HbA) on hemoglobin analysis. Individuals with thalassemia major have severe anemia and hepatosplenomegaly; they usually come to medical attention within the first two years of life. Without treatment, affected children have severe failure to thrive and shortened life expectancy. Treatment with a regular transfusion program and chelation therapy, aimed at reducing transfusion iron overload, allows for normal growth and development and may improve the overall prognosis. Individuals with thalassemia intermedia present later and have milder anemia that does not require regular treatment with blood transfusion. These individuals are at risk for iron overload secondary to increased intestinal absorption of iron as a result of ineffective erythropoiesis. [from GeneReviews]

Beta-thalassemia (ß-thalassemia) is characterized by reduced synthesis of the hemoglobin subunit beta (hemoglobin beta chain) that results in microcytic hypochromic anemia, an abnormal peripheral blood smear with nucleated red blood cells, and reduced amounts of hemoglobin A (HbA) on hemoglobin analysis. Individuals with thalassemia major have severe anemia and hepatosplenomegaly; they usually come to medical attention within the first two years of life. Without treatment, affected children have severe failure to thrive and shortened life expectancy. Treatment with a regular transfusion program and chelation therapy, aimed at reducing transfusion iron overload, allows for normal growth and development and may improve the overall prognosis. Individuals with thalassemia intermedia present later and have milder anemia that does not require regular treatment with blood transfusion. These individuals are at risk for iron overload secondary to increased intestinal absorption of iron as a result of ineffective erythropoiesis. [from GeneReviews]

Hemoglobin E - beta-thalassemia (HbE - BT) is a form of beta-thalassemia (see this term) that results in a mild to severe clinical presentation ranging from a condition indistinguishable from beta-thalassemia major to a mild form of beta-thalassemia intermedia (see these terms). [from ORDO]

Hemoglobin H disease is a subtype of alpha-thalassemia (see 604131) in which patients have compound heterozygosity for alpha(+)-thalassemia, caused by deletion of one alpha-globin gene, and for alpha(0)-thalassemia, caused by deletion in cis of 2 alpha-globin genes (summary by Lal et al., 2011). When 3 alpha-globin genes become inactive because of deletions with or without concomitant nondeletional mutations, the affected individual has only 1 functional alpha-globin gene. These people usually have moderate anemia and marked microcytosis and hypochromia. In affected adults, there is an excess of beta-globin chains within erythrocytes that will form beta-4 tetramers, also known as hemoglobin H (summary by Chui et al., 2003). Hb H disease is usually caused by the combination of alpha(0)-thalassemia with deletional alpha(+)-thalassemia, a combination referred to as 'deletional' Hb H disease. In a smaller proportion of patients, Hb H disease is caused by an alpha(0)-thalassemia plus an alpha(+)-thalassemia point mutation or small insertion/deletion. Such a situation is labeled 'nondeletional' Hb H disease. Patients with nondeletional Hb H disease are usually more anemic, more symptomatic, more prone to have significant hepatosplenomegaly, and more likely to require transfusions (summary by Lal et al., 2011). [from OMIM]