Postnatal changes in the quantities of globin chains and hemoglobin types in two babies with Hb H disease

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Abstract
We have studied two babies with Hb H disease from birth to about six months of age and analyzed the changes in the relative quantities of the five globin chains (α, β, Gγ, Aγ) and the four hemoglobins (Hb F, Hb A, Hb Bart's, Hb H) using different high performance liquid chromatography procedures. The types of Hb H disease were —(SEA)/‐α (3.7 kb) and —(Fil)/‐α (3.7 kb); the larger—(Fil) deletion includes the functional 2‐globin gene, explaining the higher chain level in the baby with the —(SEA)/‐α (3.7 kb) type. The functional hemoglobin level at birth (Hb A + Hb F) was 11 to 12 g/dl with 3 to 4 g/dl Hb Bart's (γ4). Only 5% of the “fast‐moving” hemoglobin was Hb H (β4). The level of Hb F at birth was low (less than 50% of the total Hb A + Hb F). After birth, the α and γ chain production decreases rapidly resulting in a severe anemia (total functional hemoglobin ∼7 g/dl) at 30 to 60 days postnatally, improving gradually to 8.5–9.5 g/dl at age of three months. The preferential formation of Hb A over Hb F at birth, and presumably prenatally, has the advantage that the level of the highly unstable Hb H is kept low; it also results in low levels of Hb F impairing the oxygen transfer capability of the fetal blood.