A patient with hemoglobin S and elevated hemoglobin F may either have a serious hemoglobinopathy or a relatively benign condition.


Syndromes associated with hemoglobin S and elevated hemoglobin F:

(1) homozygous hemoglobin S (sickle cell disease)

(2) hemoglobin S and beta0-thalassemia

(3) heterozygous hemoglobin S (sickle cell trait) and hereditary persistence of hemoglobin F (HPHF)


In Blacks the most common form of hereditary persistence of hemoglobin F encountered is the heterozygous deletional trait, which is associated with pancellular (homocellular) distribution of the hemoglobin F.



Sickle Cell Disease or Sickle-Thalassemia

Sickle Cell Trait and Heterozygous HPHF


symptomatic, often from a young age


percent hemoglobin F

5 to 30%

20 to 40%

distribution of hemoglobin F in RBCs




The presence of sickle cell trait and the nondeletional form of hemoglobin F would give a hemoglobin F level comparable to sickle cell disease or sickle-thalassemia. It could also show a heterocellular distribution of hemoglobin F. However, it would have a relatively benign course.


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