Hereditary persistence of hemoglobin F is protective against red cell sickling. A man in his late twenties (27 years old) was hospitalized with Acute chest syndrome and a severe vaso-occlusive crisis....

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Extracted text: Hereditary persistence of hemoglobin F is protective against red cell sickling. A man in his late twenties (27 years old) was hospitalized with Acute chest syndrome and a severe vaso-occlusive crisis. Physica! exams did not show any remarkable findings. These hypoxic episodes were explained by lab findings which showed the presence of abnormal haemoglobin S (HbS), indicative of Sickle Cell Disease. Besides it and the normal adult haemoglobin (HbA) was found also Fetal Haemoglobin (HbF) in high percentage. 1. What is the difference between HbA and HbF? 2. What is the mechanism of transforming HbF to HbA and in which age this transformation ends? 3. What is HbS and what's happen in patients with this haemoglobin abnormality? 4. Why in this patient the problems started so late in age? Is the presence of residual HbF protection in Sickle cell anemia or thalasemias? 5. Can this knowledge be used as a treatment for SCD?