Hb Potomac (101 Glu → Asp): speculations on placental oxygen transport in carriers of high-affinity hemoglobins

Abstract

Blood from a woman with unexplained erythrocytosis had increased oxygen affinity, but no abnormality could be detected by electrophoresis or chromatography of her hemolysate. Separation of the tryptic peptides of her β chains disclosed 2 half-sized peaks in the region of β T-11. The faster of these was abnormal, with the structure β 101 Glu → Asp. The new hemoglobin was called 'Potomac'. Three of the proband's 4 surviving siblings and both of her children were carriers. Differences in the ratio of carrier:normal children born to male or female carriers of 23 other high-affinity hemoglobins were not significant. The high proportion of carriers in this kindred was probably due to chance alone, and not because high maternal oxygen affinity interfered with oxygen transport to fetuses with normal hemoglobin.