fetal hemoglobin n hemoglobin that consists of two alpha chains and two gamma chains and that predominates in the blood of a newborn and persists in increased proportions in some forms of anemia (as thalassemia) called also hemoglobin F
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the hemoglobin normally comprising more than half of that in the fetus, composed of two alpha and two gamma polypeptides (α2Aγ2F); it has higher affinity for oxygen under physiologic conditions than does hemoglobin A. It is present in minimal amounts in adulthood and is abnormally elevated in aplastic anemia, leukemia, and certain types of thalassemia. Called also h. F.Medical dictionary. 2011.