Hemoglobin abnormal, anemias caused

D-13) The hemoglobinopathies. Mutations that change a single amino acid in a hemoglobin molecule may cause abnormally functioning red blood cells and anemia. 

Newborn infants (especially the premature) have low plasma levels of vitamin E (the vitamin E concentration in full-term newborn infants is about one-third that of adults and that of premature infants is even lower), because transfer of vitamin through the placenta to the fetus is limited. As a result, hemolytic anemia (caused by shortened life span of red cells) may occur in the early weeks of life. In this condition, the membranes of the red blood cells are weakened by the action on them of the products of peroxidation of polyunsaturated fats and the cells rupture easily, producing a condition characterized by edema, skin lesions, and blood abnormalities. Supplements of vitamin E bring about increeises in blood levels of the vitamin, decreases in red blood cell hemolysis, and a return to normal hemoglobin levels. 

Hemoglobinopathies have traditionally been defined as a family of dis orders caused by production of a structurally abnormal hemoglobin molecule, synthesis of insufficient quantities of normal hemoglobin, or, rarely, both. Sickle-cell anemia (HbS), hemoglobin C disease (HbC), and the thalassemia syndromes are representative hemoglobinopathies that can have severe clinical consequences. The first two conditions result from production of hemoglobin with an altered amino acid sequence, whereas the thalassemias are caused by decreased produc tion of normal hemoglobin. 

The hematopoietic system is affected by both short- and long-term arsenic exposure. Arsenic is known to cause a wide variety of hematological abnormalities like anemia, absolute neutropenia, leucopenia, thrombocytopenia, and relative eosinophilia - more common than absolute esino-philia, basophilic stippling, increased bone marrow vascularity, and rouleau formation (Rezuke et al, 1991). These effects may be due to a direct hemolytic or cytotoxic effect on the blood cells and a suppression of erythropoiesis. The mechanism of hemolysis involves depletion of intracellular GSH, resulting in the oxidation of hemoglobin (Saha et al, 1999). Arsenic exposure is also known to influence the activity of several enzymes of heme biosynthesis. Arsenic produces a decrease in ferrochelatase, and decrease in COPRO-OX and increase in hepatic 5-aminolevulinic acid synthetase activity (Woods and Southern, 1989). Subchronic... 

Sulfasalazine causes Heinz body anemia in patients with abnormal hemoglobin and hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency (48). 

A. Diseases related to abnormal hemoglobin Sickle cell anemia results from a point mutation (GAG to GTG) that causes valine to replace glutamate at position 6 in the P-globin chain. In hemoglobin Wayne, deletion of a base causes a frameshift that produces the wrong sequence of amino acids in the chain beyond position 127. 

A number of other enzymopathic substances (e.g., pyruvate kinase. Chapter 13 and pyrimidine-5 -nucleotidase. Chapter 27), abnormal hemoglobins (Chapter 28), and abnormalities of the erythrocyte cytoskeleton (Chapter 10) may cause hemolytic anemia. Because many enzymes in the red cell are identical to those in other tissues, defects in these enzymes may have pleiotropic effects. Thus, in addition to hemolytic anemia, triose phosphate isomerase deficiency causes severe neuromuscular disease, and phospho-fructokinase deficiency causes a muscle glycogen storage disease (Chapter 13). Mutations that result in decreased enzyme stability are usually most strongly expressed in erythrocytes because of their inability to synthesize proteins. 

Characteristics of the more common /3-thalassemia syndromes are summarized in Table 28-4. Not included are two different abnormal heterozygotes. Anemia results from precipitation of excess a-globin chains, premature red cell destruction in bone marrow and the circulation, and deficiency of functional hemoglobin tetramer. /S-Thalassemia major, or Cooley s anemia, occurs when /3-globin synthesis is markedly depressed or absent. The ineffective erythropoiesis causes massive erythroid proliferation, skeletal deformities, and extramedullary erythropoiesis. The usual treatment is frequent blood transfusion. 

Anemia is the abnormally low level of hemoglobin or red blood cell mass, which has the potential of limiting the delivery of oxygen to tissue. By far, the most common cause of anemia is iron deficiency, leading to small volume of red blood cells (microcytic). Another common cause of microcytic anemia is thalassemia. Certain ethnicities have higher incidences of thalassemia, for example, Mediterranean or East Asian descent. 

Sickle cell anemia is a hereditary disease in which abnormally shaped red blood cells restrict the flow of blood to vital organs in the human body, causing swelling, severe pain, and in many cases a shortened life span. There is currently no cure for this condition, but its painful symptoms are known to be caused by a defect in hemoglobin, the oxygen-carrying protein in red blood cells. 

Megaloblastic anemia A deficiency in serum hemoglobin and red blood cells (erythrocytes) in which the erythrocytes are abnormally large. This type of anemia is caused by folate or vitamin B, deficiency. 

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