Department of Cell and Molecular Biology, Medical College of Georgia, Augusta 30912-2100.
During a survey of cord blood samples of healthy Chinese babies an A gamma variant was detected by its partial separation from normal A gamma in a high performance liquid chromatographic experiment. Structural analysis of the isolated A gamma X chain identified a Val----Met substitution at position A gamma 134; this substitution created a rather unique Met-Met sequence. The ratio of A gamma X to A gamma was about 2 to 3; thus, Hb F with this variant A gamma chain appears to have approximately normal stability.