#SickleCellAwarenessMonth D20
#Tweetorial on #FetalHemoglobin (HbF), to explain hydroxyurea, gene therapy & hereditary persistence of fetal hemoglobin (HPFH)
HbF is best known inhibitor of HbS polymerization & sickling
Need >15-20% to reduce and >30% to prevent symptoms
1/6
#Tweetorial on #FetalHemoglobin (HbF), to explain hydroxyurea, gene therapy & hereditary persistence of fetal hemoglobin (HPFH)
HbF is best known inhibitor of HbS polymerization & sickling
Need >15-20% to reduce and >30% to prevent symptoms
1/6
HbF, which is needed to extract oxygen from the maternal circulation ⬇️ after birth once the baby breathes and can oxygenate their own hemoglobin
For infants with #SickleCell, this decline is slower, usually mostly complete by 6-12 months of age. Some have a slower decline
2/6
For infants with #SickleCell, this decline is slower, usually mostly complete by 6-12 months of age. Some have a slower decline
2/6
I start #Hydroxyurea at 6 mo of age, when HbF is declining and there is usually evidence of hemolysis (⬇️HbF ⬆️ reticulocytes)
I don’t wait for symptoms or a certain HbF%
HU helps - see this real-world example w/significant improvement in anemia and a healthy/happy baby
3/6
I don’t wait for symptoms or a certain HbF%
HU helps - see this real-world example w/significant improvement in anemia and a healthy/happy baby
3/6
Some worry about starting HU early in life, w/o knowing if high HbF is HPFH
I don’t worry about this.
True, deletional HPFH is rare & results in NORMAL labs
If there is anemia or ⬆️ retic, it’s not true HPFH
HU will help
Below is an example of HbS with deletional HPFH
4/6
I don’t worry about this.
True, deletional HPFH is rare & results in NORMAL labs
If there is anemia or ⬆️ retic, it’s not true HPFH
HU will help
Below is an example of HbS with deletional HPFH
4/6
It’s important to distinguish HbS-HPFH from with high baseline HbF
While higher levels of HbF ⬇️ symptoms, there are still symptoms for most unless there is deletional HPFH (HbF>35-40%, Hb 12-15ish, normal retic)
I use hydroxyurea to “top off” those with high baseline HbF
5/6
While higher levels of HbF ⬇️ symptoms, there are still symptoms for most unless there is deletional HPFH (HbF>35-40%, Hb 12-15ish, normal retic)
I use hydroxyurea to “top off” those with high baseline HbF
5/6
Some #GeneTherapy approaches (including CRISPR) aim to ⬆️ HbF w/a target HbF>30% to approach “cure”
I now use this 30% as my target for #Hydroxyurea & can accomplish it in most children w/careful dosing, dose adjustments for weight & tireless work on adherence
I ❤️HbF
6/fin
I now use this 30% as my target for #Hydroxyurea & can accomplish it in most children w/careful dosing, dose adjustments for weight & tireless work on adherence
I ❤️HbF
6/fin
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