The chemical heterogeneity of the fetal hemoglobin of black newborn babies and adults: a reevaluation.

Results from ‘y-chain analyses of over 200 cord blood samples by HPLC have shown that about 20% of the black babies carry the variant. while two types of “y-thalassemia (G ythal -thal) have also been observed. The average quantity of the chain in the A yI heterozygotes (12.7%) was slightly less than that of the A I chain (16.4%). The level of the G ychain in both heterozygous and homozygous newborn babies was the same as that of babies who were A l homozygotes (average 70.5%). Six of the babies without the chain had values between 80% and 86%. while in one this level was nearly 100%. The latter baby maintained high values in serial analyses during the first year of life. while his HbF level decreased to the expected low values. Family studies support the hypothesis that this child is homozygous for an A, 7, -thaIassemia. while the other six infants are A, , -thal heterozygotes. Two additional babies had the A + -thalassemia heterozygosity together with an A T heterozygosity. In one the A,,, ,T heterozygosity was in cis and in the other it was in trans to the A, 1, #{247} -thalassemia determinant. Three babies had HbF with G,, levels between 35% and 50%. This percentage decreased steadily with time in two infants