Anemia, Mediterranean: Better known today as thalassemia (or as beta thalassemia or thalassemia major). The clinical picture of this important type of anemia was first described in 1925 by the pediatrician Thomas Benton Cooley. The name thalassemia was coined by the Nobel Prize winning pathologist George Whipple and the professor of pediatrics Wm Bradford at U. of Rochester because thalassa in Greek means the sea (like the Mediterranean Sea) + -emia means in the blood so thalassemia means sea in the blood. Thalassemia is not just one disease. It is a complex contingent of genetic (inherited) disorders all of which involve underproduction of hemoglobin, the indispensable molecule in red blood cells that carries oxygen. The globin part of normal adult hemoglobin is made up of 2 alpha and 2 beta polypeptide chains. In beta thalassemia, there is a mutation (change) in both beta globin chains leading to underproduction (or absence) of beta chains, underproduction of hemoglobin, and profound anemia. The gene for beta thalassemia is relatively frequent in people of Mediterranean origin (for example, from Italy and Greece). Children with this disease inherit one gene for it from each parent. The parents are carriers (heterozygotes) with just one thalassemia gene, are said to have thalassemia minor, and are essentially normal. Their children affected with beta thalassemia seem entirely normal at birth because at birth we still have predominantly fetal hemoglobin which does not contain beta chains. The anemia surfaces in the first few months after birth and becomes progressively more severe leading to pallor and easy fatigability, failure to thrive (grow), bouts of fever (due to infections) and diarrhea. Treatment based on blood transfusions is helpful but not curative. Gene therapy will, it is hoped, be applicable to this disease.
- Anemia, pernicious
Anemia, pernicious: Low red blood cell count caused by inadequate vitamin B12. Abbreviated PA. Patients with PA do not produce intrinsic factor (IF), a substance that allows the body to absorb vitamin B12 from foods. The resulting inadequacy of vitamin B12 hampers the production of red blood cells. PA can be treated by injection of […]
Relating to anemia, the condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased. Persons with anemia may feel tired and fatigue easily, appear pale, develop palpitations (feelings of rapid heart beating) and […]
- Anemia, sickle cell
A genetic blood disorder caused by the presence of an abnormal form of hemoglobin. These hemoglobin molecules tend to aggregate after unloading oxygen forming long, rod-like strictures that force the red cells to assume a sickle shape. Unlike normal red cells, which are usually smooth and malleable, the sickle red cells cannot squeeze through small […]
Anencephaly: A neural tube defect (NTD) that occurs when the cephalic (head) end of the neural tube fails to close, usually between the 23rd and 26th days of pregnancy, resulting in the absence of a major portion of the brain, skull, and scalp. Infants with this disorder are born without a forebrain, the largest part […]
Anergy: A state of immune unresponsiveness. Induced when the T cell’s antigen receptor is stimulated, effectively freezing T cell responses pending a “second signal” from the antigen-presenting cell. The delivery of the second signal by the antigen-presenting cell rescues the activated T cell from anergy, allowing it to produce the lymphokines necessary for the growth […]