A new beta-chain variant, Hemoglobin Windsor [beta 11 (A8)Val----Asp] was discovered in a 9-month-old child who presented with a hemolytic anemia of 59 g/l with an intercurrent viral infection. Her blood film demonstrated fragmented cells, target cells, stipple cells, nucleated red cells, polychromasia and some spherocytes, indicative of acute hemolysis. Hemoglobin electrophoretic studies were requested and a beta-chain variant, constituting 27% of the total hemoglobin, separated towards the anode under alkaline conditions. The variant was unstable, producing numerous "Hb H"-like inclusions and a positive isopropanol stability test. The variant hemoglobin was purified by precipitation. The variant beta-chain was purified by column chromatography and its tryptic peptides fractionated by high performance liquid chromatography. Amino acid analysis and sequence data indicated that the valine at position 11(A8) had been substituted by an aspartic acid residue. This substitution, in the bottom of the heme pocket, has resulted in instability of the hemoglobin molecule and an increase in oxygen affinity. The variant appears to have resulted from a spontaneous mutation as both parents are hematologically normal. A younger sibling is also hematologically normal.

A new alpha chain hemoglobin variant, Hb Hobart, alpha 20(Bl)His----Arg, was detected in a 60-year-old female of British nationality. The proposita had a history of severe rheumatoid arthritis and had been treated for many years for a refractory microcytic anemia and/or iron deficiency. A hemoglobin electrophoresis screen indicated the presence of a hemoglobin variant, with electrophoretic characteristics similar to a Hb Lepore. However, the level of the variant (17.9%) and the presence of a minor variant Hb A2 band (0.4%) suggested that further investigation was indicated. The variant hemoglobin was purified by column chromatography and the alpha chain subjected to aminoethylation and tryptic digestion. Peptide mapping and amino acid analysis indicated that the histidine residue 20 had been substituted by an arginine residue. The substitution in Hb Hobart is at the first residue in the B Helix of the alpha chain of hemoglobin. As this is an externally placed amino acid in the hemoglobin molecule, a substitution at this position of the hemoglobin molecule would not be expected to cause any functional problems. A family study has shown that at least three other relatives are heterozygous for Hb Hobart. These family members have normal hematological findings.

A new beta-chain hemoglobin variant, Hb Randwick [beta 15(A12)Trp----Gly] was detected in a 43-year-old female of Northern Italian parentage. During investigation for possible diabetes, mild red cell changes were noted and hemoglobin electrophoresis studies were requested. Independently, her sister's assessment had resulted in similar investigations. The most prominent findings were numerous "Hb H"-like inclusions and a positive isopropanol stability test. The hemoglobin variant separated poorly towards the anode at pH 9.2 and the level was estimated to be between 48-50% of the total hemoglobin. The variant beta-chain was partially purified by column chromatography, and its tryptic peptides fractionated by high performance liquid chromatography. Amino acid analysis and sequence data indicated that the tryptophan at residue 15 (A12) had been substituted by a glycine residue. Further study has indicated that eight other family members are heterozygous for the variant; they are clinically normal with no evidence of splenomegaly or history of jaundice, although four of them showed a mild reticulocytosis.