Which haemoglobin type is the foetal haemoglobin?

Which haemoglobin type is the foetal haemoglobin?

• A. Haemoglobin A (HgbA)
• B. Haemoglobin H (HgbH)
• C. Haemoglobin S (HgbS)
• D. Haemoglobin F (HgbF)

Answer: (D)

During development, different globin chains are produced to suit the needs of the growing fetus. The foetus relies on HbF, which is made of two alpha and two gamma chains (α2γ2). This form binds oxygen more tightly, helping the fetus extract oxygen from the mother’s blood across the placenta. After birth, gamma chains are replaced by beta chains to form HbA, the adult hemoglobin. HbS is the sickle variant from a beta chain mutation, and HbH is an abnormal tetramer seen in certain thalassemias, not the normal fetal form. So the foetal hemoglobin is HbF.

During development, different globin chains are produced to suit the needs of the growing fetus. The foetus relies on HbF, which is made of two alpha and two gamma chains (α2γ2). This form binds oxygen more tightly, helping the fetus extract oxygen from the mother’s blood across the placenta. After birth, gamma chains are replaced by beta chains to form HbA, the adult hemoglobin. HbS is the sickle variant from a beta chain mutation, and HbH is an abnormal tetramer seen in certain thalassemias, not the normal fetal form. So the foetal hemoglobin is HbF.