Sickle cell syndromes. I. Hemoglobin SC-alpha-thalassemia.
Hematologic and globin synthesis studies were performed in a black American family in which the genes for alpha-thalassemia and hemoglobins (Hb) S and C were segregating. The following distribution of these abnormalities was found: father, sickle cell trait + alpha-thalassemia; mother, HbC trait + alpha-thalassemia, propositus, HbSC + alpha-thalassemia; older sibling, alpha-thalassemia trait; and younger sibling, hemoglobin H disease. The child with HbSC-alpha-thalassemia demonstrated more severe anemia and a more hemolytic picture than is typical of HbSC disease. Her erythrocytes exhibited decreased osmotic fragility in comparison with HbSC erythrocytes, but had an indistinguishable oxygen equilibrium curve and 2, 3-diphosphoglycerate (2, 3-DPG) level. Erythrocyte sickling in the patient, however, was significantly reduced, with less than 35% sickle forms observed at nearly complete oxygen desaturation. The sibling with hemoglobin H disease exhibited 26% Bart's (gamma4) hemoglobin at birth, a level comparable with that seen in infants with HbH disease in Far Eastern populations. At age 5 months typical findings of mild hemoglobin H disease appeared, with HbH making up 6.5% of the total hemoglobin.
D000755:Anemia, Sickle Cell / Q000097:blood* / Q000235:genetics; D002648:Child; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005914:Globins / Q000096:biosynthesis; D006444:Hemoglobin C / Q000032:analysis; D006445:Hemoglobin C Disease / Q000097:blood* / Q000235:genetics; D006451:Hemoglobin, Sickle / Q000032:analysis; D006801:Humans; D009996:Osmotic Fragility; D010375:Pedigree; D012805:Sickle Cell Trait / Q000097:blood* / Q000235:genetics; D013789:Thalassemia / Q000097:blood* / Q000235:genetics
D006451:Hemoglobin, Sickle; D005914:Globins; D006444:Hemoglobin C