Hemoglobin FHouston: A Fetal Variant

A fetal hemoglobin variant, designated hemoglobin FHouston, was found in the cord blood sample of a healthy, term Negro infant. The variant, comprising about 15 per cent of the total cord blood hemoglobin, diminished concomitantly with hemoglobin F, and it was barely detectable in the blood when the infant was 4 months old. The hemolysates of the parents and two siblings resolved into the usual adult pattern, but a trace amount of a fraction similar to hemoglobin FHouston was present in the father’s hemolysates and not in the mother’s. The ultraviolet absorption spectrum indicates that hemoglobin FHOUSTON contains γ polypeptide chains, and immunologic studies reveal the presence of both α and γ chains. In hybridization tests the alteration appears in the γ chain. Peptide chromatograms of hemoglobin FHouston indicated the presence of α and γ chains, but failed to reveal an abnormality. Amino acid analyses suggest that there may be a substitution of an alanyl for a glutamyl residue.