Further cases of Hb Hirosaki in two Japanese families.

Hb Hirosaki (alpha 43(CE1)Phe----Leu) was recently found anew in two Japanese families. The probands had chronic hemolytic disorders, while two other carriers of the same Hb in one family did not exhibit increased hemolysis. Hb Hirosaki comprised 5 and 2% of the total Hb in the splenectomized and non-splenectomized proband, respectively, while it comprised only 1% in the two clinically silent carriers. The expected nucleotide substitution was found in the alpha 2 (rather than alpha 1) globin gene in 1 proband. The abnormal globin was synthesized (with incorporation of [3H]-leucine) at about 30 and 20% of the total alpha-chain in reticulocytes of the probands and in those of the silent carriers, respectively. The specific radioactivity of the abnormal chain was about 20-times higher than that of the normal counterpart in the non-splenectomized patient and silent carriers (7-times in the splenectomized patient). The total alpha/beta radioactivity ratio was much higher than unity. The newly synthesized Hb Hirosaki had a slightly high isoelectric point and appeared just in front of normal Hb A in anion-exchange chromatography, but the electric charge of aged Hb Hirosaki was indistinguishable from that of Hb A. These results suggest that Hb Hirosaki is quite unstable, and is rapidly denatured and degraded after biosynthesis. The physical number of the alpha globin genes was normal in all subjects.