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Phylogeny of Normal and Abnormal Hemoglobin Genes
Published in S. K. Dutta, DNA Systematics, 2019
Embryonic hemoglobins4 are synthesized in minute quantities in the first few weeks of gestation by yolk sac erythropoietic cells. For obvious reasons, it is the least accessible and the most poorly known type of hemoglobin. Three types of embryonic hemoglobin are known: Hb Gower I, Hb Gower II, and Hb Portland. These hemoglobins are combinations of the embryonic α chain known as zeta, the embryonic non-α chain known as epsilon,7 and the γ chain. The compositions of these hemoglobins, as they are presently understood, are shown in Table 1.
Electrophoresis features and genotypes of Hb bart’s hydrops fetalis
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2020
Youqiong Li, Liang Liang, Mao Tian, Ting Qing, Xin Wu
Usually, molecular diagnosis is used as confirmatory laboratory test, but it often requires at least a week (this is the time required for testing process in Chinese hospital clinical laboratory). For affected pregnancies, the result can not be obtained early enough to prevent maternal morbidity. Since 2010, CE is used to make rapid diagnosis of Hb Bart’s disease in our hospital. As shown in Figure 3, Hb Bart’s disease displays a special pattern of embryonic hemoglobin fractions which is different from Hb H disease and heterozygote α-thalassemia (Figures 1 and 2). CE, which separates Hb fractions and allows their quantification, can measure Hb H, Hb Bart’s, Epsilon 4, Hb Gower1 and Hb Portland directly from the electrophoregrams. Embryonic hemoglobin fractions (Epsilon4, Hb Gower1 and Hb Portland) can only be detected in the second or third trimester of pregnancy in the case of Hb Bart’s disease. Therefore, it can be diagnosed by CE quicker than by genetic analysis. By high performance liquid chromatography (HPLC), Hb Bart’s and H are eluted in the void volume and therefore can only be distinguished when their concentrations are very high (>5%). Even when they are visualized, the quantification is not possible [14].
Sickle cell disease in the era of precision medicine: looking to the future
Published in Expert Review of Precision Medicine and Drug Development, 2019
Martin H Steinberg, Sara Kumar, George J. Murphy, Kim Vanuytsel
In the 10 years since the discovery of iPSCs, the field has moved forward rapidly. Although the biologic insights from this work have been impressive, the application to human therapeutics has been minimal. Notably, the use of iPSC-derived erythroid progenitor cells as a potential cell-based therapeutic for sickle cell anemia would take advantage of 2 impactful characteristics of how the cells are currently produced: the ability to make unlimited numbers of isogenic, iPSC-derived erythroblasts and the fetal/embryonic hemoglobin phenotype of these cells. Isogenic cells should not evoke an immune response. Cells producing predominantly HbF will prevent polymerization of any HbS present while adequately transporting oxygen. Thus, without manipulation of the genome or chronic immunosuppression, a potentially curative cellular therapy could be manufactured centrally and be available for reinfusion in any infusion center.