A new case of Hb Little Rock [beta 143(H21)His----Gln], a high affinity variant. Study during pregnancy

A new case of Hb Little Rock [beta 143(H21)His----Gln] is described. This high affinity variant (P50 = 15 mm Hg in whole cells) has a nearly normal cooperativity. The abnormal beta chain is readily detectable using urea-Triton X-100 electrophoresis. The altered beta T-14 peptide was separated by high performance liquid chromatography. The proposita was followed during a pregnancy. Oxygen unloading was reduced, but normal oxygen loading was maintained in the fetus. There were neither placental abnormalities, nor intrauterine growth retardation.