Properties of the double substituted hemoglobin C Ziguinchor alpha2A beta 2 6 Glu replaced by Val 58 Pro replaced by Arg.

We have previously described the structural identification of the sickle hemoglobin variant Hb C Ziguinchor (alpha2A beta2 6 Glu replaced by Val, 58 Pro replaced by Arg). This hemoglobin was found in two generations (three members) of an African family. In two family members, the clinical picture resembled that typical of a sickle cell trait, while the third member showed a more extreme clinical condition due to complication by an iron deficiency anemia. The functional properties of Hb C Zig. in red blood cells or in dilute solutions were identical to those of Hb S. The gelling behaviour of deoxy Hb C Zig. was also indistinguishable from that of Hb S. These findings suggest that, in contrast to the case of Hb C Harlem, the second substitution in position beta58 in Hb C Zig. does not interfere with the intermolecular interactions determined by the sickle substitution.