THE THIRD INSTANCE OF Hb M SASKATOON DISEASE DISCOVERED IN JAPAN
A four-year-old girl who had been persistently cyanotic since her birth notwithstanding the absence of congenital heart disease was seen at the Kanagawa Children's Medical Center (Yokohama) in 1974. The absorption spectrum of acid methemoglobin type hemolysate of this patient failed to show the peak at 630 nm and the depression at 600 nm which were characteristic of methemoglobin of a normal subject. Cellulose acetate membrane electrophoresis (pH 7.1) of methemoglobin type hemolysate yielded a discrete greenish stripe of an abnormal hemoglobin to the anode side of the stripe of normal methemoglobin which was reddish brown. The abnormal hemoglobin was purified and collected from the methemoglobin type hemolysate by cellulose acetate membrane electrophoresis (pH 7.1). Exact investigation of the absorption curves of the acid met Hb type hemolysate and the purified acid met Hb type abnormal hemoglobin solution not only over the range of visual spectrum but also over the ultraviolet region, yielded the results reminiscent of Hb M Saskatoon. The α and the β chains of the abnormal globin were aminoethylated, digested with trypsin, and fingerprinted. Amino acid analysis of abnormal peptide spots on the fingerprint revealed a β chain anomaly which was entirely consistent with Hb M Kurume (α2β263 His → Tyr). This is the third instance of Hb M Saskatoon (M Kurume) discovered in Japan.