Fetal Hemoglobin in Sickle Hemoglobinopathies: High HbF Genotypes and Phenotypes
Department of Medicine, Division of Hematology/Oncology, Center of Excellence for Sickle Cell Disease, Center for Regenerative Medicine, Genome Science Institute, Boston University School of Medicine and Boston Medical Center, 72 E. Concord St., Boston, MA 02118, USA
J. Clin. Med. 2020, 9(11), 3782; https://doi.org/10.3390/jcm9113782
Received: 3 November 2020
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Revised: 17 November 2020
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Accepted: 19 November 2020
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Published: 23 November 2020
(This article belongs to the Special Issue The Clinical Epidemiology of Sickle Cell Disease, a Severe Multi-Organ Affection)
Fetal hemoglobin (HbF) usually consists of 4 to 10% of total hemoglobin in adults of African descent with sickle cell anemia. Rarely, their HbF levels reach more than 30%. High HbF levels are sometimes a result of β-globin gene deletions or point mutations in the promoters of the HbF genes. Collectively, the phenotype caused by these mutations is called hereditary persistence of fetal hemoglobin, or HPFH. The pancellularity of HbF associated with these mutations inhibits sickle hemoglobin polymerization in most sickle erythrocytes so that these patients usually have inconsequential hemolysis and few, if any, vasoocclusive complications. Unusually high HbF can also be associated with variants of the major repressors of the HbF genes, BCL11A and MYB. Perhaps most often, we lack an explanation for very high HbF levels in sickle cell anemia.
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Keywords:
hereditary persistence of fetal hemoglobin; gamma-globin gene; gene deletion; globin gene expression; genotype/phenotype
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MDPI and ACS Style
Steinberg, M.H. Fetal Hemoglobin in Sickle Hemoglobinopathies: High HbF Genotypes and Phenotypes. J. Clin. Med. 2020, 9, 3782. https://doi.org/10.3390/jcm9113782
AMA Style
Steinberg MH. Fetal Hemoglobin in Sickle Hemoglobinopathies: High HbF Genotypes and Phenotypes. Journal of Clinical Medicine. 2020; 9(11):3782. https://doi.org/10.3390/jcm9113782
Chicago/Turabian StyleSteinberg, Martin H. 2020. "Fetal Hemoglobin in Sickle Hemoglobinopathies: High HbF Genotypes and Phenotypes" Journal of Clinical Medicine 9, no. 11: 3782. https://doi.org/10.3390/jcm9113782
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