Abstract
Summary
Positive sickling was found in 7 or 8.3% of blood samples from 84 newborn Negro babies, with 3 to 15% of erythrocytes capable of sickling. In free electrophoresis of the hemoglobin of 4 of these 7, the S hemoglobin content ranged from “not demonstrable” to 21%. Blood samples from one baby with sicklemia were studied at birth, 2 weeks, 6 weeks and 7 months respectively, with a progressive increase of sickling erythrocytes of from 13% at birth to 97% at 7 months, and a corresponding increase in S hemoglobin of from about 14 to 50%. Three of the other babies with sicklemia were reexamined at 41/2 to 7 months, at which time almost 100% of the erythrocytes sickled and S hemoglobin values were of the adult order of 40 to 50%. The presence of hemoglobin C trait was detected in the blood of one new-born baby of the 84, with a hemoglobin C content of only 8%. The rarity of sickle cell anemia and the paucity of sickling erythrocytes in young infants are explained by a quantitative delay in the production of S hemoglobin which, like normal adult hemoglobin (and probably hemoglobin C), does not reach adult levels until the age of about 41/2 months.
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