What does elevated hemoglobin F mean?
Hb F is often mildly to moderately elevated in sickle cell disease, aplastic anemia, acute leukemia, and myeloproliferative disorders such as juvenile myelomonocytic leukemia, hereditary spherocytosis, and alpha-thalassemia minor. It is commonly increased in hemoglobinopathies associated with hemolysis.
How is HPFH inherited?
Having HPFH trait is harmless to the carrier. However, a few newborns inherit a gene for HPFH from one parent and a sickle cell gene from the other. This causes a condition called hemoglobin S/HPFH (HbS/HPFH), which looks similar to sickle cell anemia on laboratory testing at birth.
What causes elevated HbF?
HbF is elevated in inherited conditions, such as hereditary persistence of HbF, hereditary spherocytosis, and thalassemia. The level of HbF is also increased in acquired states, such as pregnancy, aplastic anemia, thyrotoxicosis, hepatoma, myeloproliferative disorders, or hypoplastic myelodysplastic syndrome.
What causes HPFH?
Hereditary persistence of fetal hemoglobin (HPFH) is a condition with significant fetal hemoglobin (HbF) production which continues in adulthood. This is usually caused by mutations in the β- or α-globin gene cluster or the γ promoter gene region.
How is HPFH diagnosed?
Diagnostic methods. Diagnosis is based on the presence of a significant elevation in HbF ranging from 10-40% in heterozygotes with normal or near normal red blood cell indices. HbF is homogeneously distributed among the erythrocytes and HbA2 is normal or reduced.
Can hemoglobinopathies be cured?
There is currently no cure for hemoglobinopathies. Children who receive treatment may still experience some of the signs mentioned in Early Signs. It is important to screen for and treat hemoglobinopathies because, if left untreated, babies with a severe form of the condition can die within their first year of life.
Why is HbF replaced by HbA?
Blood transfusion with adult haemoglobin (HbA) replaces foetal haemoglobin (HbF). HbA has a lower affinity for oxygen than HbF and therefore leads to increased oxygen availability to the tissues including the retina.
When does HbF change to HbA?
about 32-36 wk of
HbF, optimal for oxygen transport in utero, is progressively replaced by HbA from about 32-36 wk of gestation (1). This maturational phenomenon is clinically important and shows marked individual variation.
What causes increased HbF?
What is HbF in sickle cell disease?
Fetal hemoglobin (HbF) modulates the phenotype of sickle cell anemia by inhibiting deoxy sickle hemoglobin (HbS) polymerization. The blood concentration of HbF, or the number of cells with detectable HbF (F-cells), does not measure the amount of HbF/F-cell.
Why does HbF increase in thalassemia?
These data suggest that the high HbF levels in HbE/β thalassemia, and other β thalassemia syndromes, result from increased erythropoietin levels leading to bone marrow expansion, and possibly increased F-cell production, combined with ineffective erythropoiesis giving a survival advantage to F cells.
What causes haemoglobinopathy?
Haemoglobinopathies are a group of recessively inherited genetic conditions affecting the haemoglobin component of blood. They are caused by a genetic change (mutation) in the haemoglobin [footnote 2] [footnote 3].
How are hemoglobinopathies treated?
Stem-cell transplantation is the preferred treatment for the severe forms of thalassemia. Supportive, rather than curative, treatment consists of periodic blood transfusions for life, combined with iron chelation.