Erythrocytosis Secondary to Increased Oxygen Affinity of a Mutant Hemoglobin, Hemoglobin Kempsey

An abnormal hemoglobin, termed hemoglobin Kempsey, was found in association with erythrocytosis in ten members of an Australian family. Genetic transmission fits an autosomal dominant pattern. Chemical characterization of hemoglobin Kempsey identified a single amino acid substitution, β^99Asp→Asn. Properties of hemoglobin Kempsey include a marked increase in oxygen affinity, retention of the Bohr effect, and decreased heme-heme interaction. Possible structure-function relations of this and other abnormal hemoglobins associated with erythrocytosis are discussed.