Are foetal blood cells more likely to sickle?

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Bill MCgee

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Are foetal blood cells more likely to sickle?
« on: 22/02/2010 15:30:03 »
Bill MCgee asked the Naked Scientists:
Another question for you to puzzle over:

In my textbook it says that "an increase in foetal Hb improves red cell function in sickle-cell patients" in reference to treatment with hydroxyurea.

Surely, however, the fetal Hb's greater affinity for oxygen will deoxygenate the affected red cells making them sickle, therefore there will be more sickle cells and a crisis is more likely?

Many thanks again

What do you think?
« Last Edit: 22/02/2010 15:30:03 by _system »


Offline JoeVector

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Are foetal blood cells more likely to sickle?
« Reply #1 on: 08/03/2010 00:44:30 »
Actually, the difference is most likely explained by the fact foetal hemoglobin is made up of alpha and gamma subunits, unlike regular human hemoglobin which has alpha and beta subunits. Since the mutation causing sickle cell disease affects only the beta subunit, replacing mutant hemoglobin with foetal hemoglobin (assuming of course, that the gamma subunit is itself devoid of any significant mutation) should relieve the symptoms.

As for deoxygenation of mutant hemoglobin furthering the problems, I don't think that could happen since foetal hemoglobin is produced at the expense of the other type, therefore even the mutant hemoglobin polymerizes more than it otherwise would, having less of it in the cell means the effect will be lessened as well.