Last Updated on April 7, 2025 by Analgesia team
Fetal Hemoglobin
HbF is the medical abbreviation for fetal hemoglobin, which is the primary type of hemoglobin in a fetus during pregnancy and early infancy:
Production
Fetal hemoglobin is made by red blood cell precursors in the bone marrow (after birth) or the fetal liver and spleen (before birth).
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Hemoglobin is made of globin chains: two alpha (α) and two gamma (γ) chains make up HbF (α2γ2).
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These chains are produced by globin genes on chromosome 11 (for gamma) and chromosome 16 (for alpha).
Levels For HbF
At birth, babies typically have half HbF and half adult hemoglobin (HbA). HbF levels usually drop to very low amounts about six months after birth.
Blood disorders
In adults or children, higher levels of HbF can indicate a blood disorder, such as:
- Thalassemia
- Myeloid leukemia
- Sickle cell anemia
Sickle cell anemia
HbF is a major genetic modulator of sickle cell disease. Some patients with sickle cell anemia have high levels of HbF, which can be associated with milder disease.
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People with these conditions often benefit from elevated levels of HbF, which can reduce disease severity.
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Why? HbF does not cause sickling like HbS (the abnormal hemoglobin in sickle cell disease), so it can reduce the frequency of painful crises and organ damage.
Lab Testing for HbF
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Hb Electrophoresis or High-Performance Liquid Chromatography (HPLC) are used to measure levels of HbF.
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Testing is important in diagnosing hemoglobinopathies and monitoring treatment.
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Protective mechanism:
Fetal hemoglobin does not readily participate in the formation of sickle hemoglobin polymers, which are responsible for the characteristic sickle shape of red blood cells in sickle cell disease.
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Genetic variation:
The amount of fetal hemoglobin produced varies between individuals, with some sickle cell patients naturally having higher levels of HbF, leading to a milder disease course.
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Therapeutic target:Researchers are actively investigating ways to increase fetal hemoglobin production in sickle cell patients through medications or gene therapy, as higher HbF levels can significantly improve clinical outcomes.
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Hereditary persistence of fetal hemoglobin (HPFH)High Fetal Hemoglobin levels can be caused by β-globin gene deletions or point mutations in the promoters of the HbF genes. This phenotype is called HPFH