Hemoglobin Bougardirey-Mali β119 (GH2) Gly → Val. An Electrophoretically Silent Variant Migrating in Isoelectrofocusing as Hb F

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Abstract
Hb Bougardirey-Mali was detected by isoelectro focusing during a screening in a 32 yr old African, a native of Mali. This abnormal Hb, representing 35% of the total, exhibited the same pI [isoelectric point] as that of Hb F. It was indistinguishable from Hb A in all the electrophoretic systems tested, and equally by its resistance to alkaline denaturation. Structural studies showed that the abnormality was localized on the .beta. chain. A fingerprint of the tryptic digest of the aminoethylated .beta. chain indicated the absence of the .beta.T12 b. The presence of an abnormal .beta.T12 b was suspected in the T14-15 spot, as indicated by the intensity of staining and its amino acid composition. .beta.T12 b was isolated by chromatography on PA 35. Sequential analysis by manual Edman-dansyl degradation showed that glycine 119 was replaced by a valine residue. This mutation was localized in a .alpha.1.beta.1 contact, which makes the molecules slightly unstable. The clinical consequences of this mutation seem minor; similar observations were reported for the other Hb mutated at the same locus, i.e., Hb Fannin-Lubbock .beta.119 Gly .fwdarw. Asp.