Hemoglobin Grange-Blanche [beta 27(B9) Ala----Val], a new variant with normal expression and increased affinity for...

Hemoglobin Grange-Blanche [beta 27(B9) Ala----Val] is a new variant found in a Portuguese family. The carriers present moderate erythrocytosis. Upon isoelectric focusing, Hb Grange-Blanche was slightly more cathodic than Hb A. beta Grange-Blanche chain migrated like the G gamma chain when submitted to electrophoresis in the presence of urea-Triton X-100. The precentage of Hb Grange-Blanche was about 50% in the heterozygous state. Oxygen affinity was increased (P50 = 22 mmHg), but heme-heme interaction was normal. An abnormal tryptic peptide (beta T3) was isolated using HPLC. Its composition allowed us to deduce unambiguously the amino acid change. The latter is the third mutation found in position 27 of the beta-chain. Because of its normal expression and its elevated affinity for oxygen, Hb Grange-Blanche contrasts with Hb Knossos [beta 27(B9) Ala----Ser], a beta-thalassemic variant with low affinity.