A case report of a patient with Hb Peterborough [β111 (G13) Val → Phe] causing a mild hemolytic anemia *
Isoelectric focusing of the hemolysate from a 52-year-old female with a mild hemolytic anemia living in Okayama prefecture, showed an abnormal Hb band around the zone of Hb F, although a DEAE-HPLC of it did not reveal any abnormal Hb peaks. An isopropanol precipitation test of the hemolysate was positive, showing the presence of an unstable Hb. Amino acid analysis of the peptides from the isolated abnormal Hb using of a reversed phase HPLC sugested that there was an amino acid substitution in the βTp-12a peptide（β105-112:Leu-Leu-Gly-Asn-Val-Leu-Val-Cys）. However, amino acid substitution was not detected by amino acid composition analysis. Direct sequencing of the PCR product showed that the first nucleotide of the triplet codon（GTC）at the 111th position of the b-globin gene had changed from G to T, suggesting an amino acid substitution of Val to Phe, which led us to identify the abnormal Hb as Hb Peterborough［β111（G13）Val→Phe］． Hb Peterborough has been reported as an unstable abnormal Hb with a low oxygen affinity, and it is considered to cause a mild hemolytic anemia. In addition, Hb biosynthesis disclosed slightly lower values of β/α＝0.72-0.79, which were considered to be due to the instability of an abnormal Hb with aβ-globin chain variant. The patient's younger brother was a carrier of the same Hb, and showed compensated hemolysis and a slightly lower β/α value. An discovery of this Hb in Japanese is the second instance of its detection following a case in Osaka prefecture. The lineage relationship between these cases has not been determined. (Accepted on June 15，2004）
