Hemoglobin Athens‐Georgia [α 2 β 2 40(C6)Arg→Lys] in association with β 0 ‐thalassemia in Tunisia

We describe an Hb Athens‐Georgia (Hb A‐Ga)/β 0 ‐thalassemia compound heterozygosity, found in a Tunisian patient. Oxygen binding studies of red cell suspensions of this patient, containing approximately 95% Hb A‐Ga, revealed an almost normal oxygen affinity. Nevertheless, dilute solutions of Hb A‐Ga showed an increased overall oxygen affinity and decreased heme‐heme interaction. This could be explained by a tetrameric hemoglobin with normal oxygen binding properties but with increased dissociation into monomers or dimers, as a consequence of a structural abnormality within the α 1 β 2 interface. Such an interpretation would explain the increased oxygen affinity reported in previous studies performed on heterozygous Hb A/Hb A‐Ga patients.