A carrier of hemoglobin Chesapeake, born of a normal mother, had a cord-blood hematocrit of 60%. The oxygen affinity of his blood was increased. Hemoglobin F-Chesapeake (α2Chesγ2), partially purified from the infant's blood, had oxygen affinity greater than that of hemoglobin A, but less than that of the adult form of the abnormal hemoglobin (α2Chesβ2). These findings suggest that the conformation of that part of the γ chain which contacts the site of amino acid substitution in Hb F-Chesapeake is similar to the analogous region of hemoglobpn F. They also support the hypothesis that regulation of erythropoiesis in late fetal life is similar to that of the adult, and is under fetal control.Speculation
The conformation of that part of the γ chain which contacts the site of amino acid substitution in hemoglobin F-Chesapeake is similar to the conformation of the analogous region of the γ chain of hemoglobin F. Erythropoiesis in late fetal life is determined by the oxygen affinity of fetal blood (as well as by placental blood flow and structure, fetal cardiac output, and tissue oxygen utilization), and probably is regulated by erythropoietin produced by the fetus.