Hemoglobin Dhonburi alpha 2 beta 2 126 (H4) Val----Gly: a new unstable beta variant producing a beta-thalassemia intermedia phenotype in association with beta zero-thalassemia.

While investigating the mechanism of a beta-thalassemia intermedia phenotype in a 34 year old Thai male, a new Hb variant beta 126 Val----Gly named Hb Dhonburi was discovered. Genetic and structural studies revealed the existence of a beta zero-thalassemia genotype in association with the beta variant. The new variant is unstable but exhibits normal oxygen binding properties. Hb Dhonburi was also discovered in the mother of the propositus in association with Hb E.

Hemoglobin Saverne: a new variant with elongated beta chains: structural and functional properties.

A 26-year-old French woman born in Saverne (France) was found to have Heinz body hemolytic anemia. Isoelectrofocusing showed the presence of an abnormal band amounting to 35% of the total hemoglobin concentration, suggesting a beta variant. Structural analysis of the abnormal beta chain showed an elongated C-terminal segment. Histidine 143 is replaced by a proline and the C-terminal sequence is identical to the corresponding segment of Hb Cranston. This new variant, named Hb Saverne, has beta chains composed of 156 amino acid residues. Studies of its functional properties showed that Hb Saverne is an unstable, high affinity variant with low cooperativity.

Glycerated hemoglobin alpha 2 beta 2(82) (EF6) N-epsilon-glyceryllysine: a new post-translational modification occurring in erythrocyte bisphosphoglyceromutase deficiency.

A new minor Hb fraction initially designated Hbx, has been found in the hemolysate of a erythremic patient that we have previously described with a complete erythrocyte bisphosphoglyceromutase (BPGM) (E.C.2.7.5.4.) deficiency. Hbx (3.5% of the total) was detected by isoelectric focusing (IEF) and exhibited electrophoretic and chromatographic properties similar to that of several variants of the Hb central cavity. By density fractionation of red cells, it was demonstrated that Hbx was an aging hemoglobin as in the case of glycated Hb A1c. Functional studies revealed a low oxygen affinity and almost complete inhibition of the allosteric effect of the organic phosphate effectors. Structural studies demonstrated an absence of tryptic cleavage between the peptides beta T9 and beta T10 suggesting the presence of an adduct on Lys beta 82 or on a neighboring residue. FAB mass spectrometry, CID/MIKE spectra and a specific enzymatic assay with glyoxylate reductase, demonstrated that the 82 adduct was a glycerate moiety. It was concluded that Hbx was a glycerylated Hb: alpha 2 A beta 2(82) (EF6) N-epsilon-glyceryllysine, to our knowledge the first example of glycerylated protein. The mechanism of formation of glyceryl-Hb, which was found in the four studied subjects with a BPGM deficiency, remains to be determined.

Glycerated hemoglobin, alpha 2A beta 2(82) (EF6) N epsilon-glyceryllysine. A new post-translational modification occurring in erythrocyte bisphosphoglyceromutase deficiency.

A new minor Hb fraction initially designated Hbx, has been found in the hemolysate of an erythremic patient that we have previously described with a complete erythrocyte bisphosphoglycerate mutase (EC 5.4.2.4) deficiency. Hbx (3.5% of the total) was detected by isoelectric focusing and exhibited electrophoretic and chromatographic properties similar to those of several variants of the Hb central cavity. By density fractionation of red cells, it was demonstrated that Hbx was an aging hemoglobin as in the case of glycated Hb A1c. Functional studies revealed a low oxygen affinity and almost complete inhibition of the allosteric effect of the organic phosphate effectors. Structural studies demonstrated an absence of tryptic cleavage between the peptides beta T9 and beta T10 suggesting the presence of an adduct on Lys beta 82 or on a neighboring residue. Fast atom bombardment mass spectrometry and a specific enzymatic assay with glyoxylate reductase demonstrated that the beta 82 adduct was a glycerate moiety. It was concluded that Hbx was a glycerylated Hb, alpha 2A beta 2(82) (EF6) N epsilon-glyceryllysine, to our knowledge the first example of glycerylated protein. The mechanism of formation of glyceryl Hb, which was found in the four studied subjects with a bisphosphoglyceromutase deficiency, remains to be determined.

Hemoglobin J Iran alpha 2 beta 2 77 (EF1) his----Asp in a Russian-Armenian family.

A third case of Hb J Iran is reported. The propositus is of Russian-Armenian origin and was investigated for hematuria. The electrophoretic behavior and the characterization of primary structure are described. Hb J Iran is stable and has normal functional properties. High resolution Nuclear Magnetic Resonance spectra suggest the presence of structural perturbations in the heme pocket of the variant. Solubility studies of Hb S/Hb J Iran mixture indicated that His beta 77 belongs to a contact region of deoxy Hb S polymers.

Hb Kokura alpha 2 47 (CE5) Asp----Gly beta 2 in a French Jewish family.

An abnormal hemoglobin was found in a young polycythemic man. Case study showed that the polycythemia was not due to hemoglobinopathy as the blood oxygen affinity was normal. Structural study of this variant permitted the characterization of a Hb Kokura alpha 2 47 (CE5) Asp----Gly beta 2 for the first time in France.

Hemoglobin San Diego/beta zero thalassemia in a Greek adult.

Interaction of beta zero thalassemia with Hb San Diego [a high affinity hemoglobin variant, alpha 2 beta (2)109(G11)Val----Met] in a 29-year-old Greek male is described. A marked polycythemia with low MCH and MCV, but minor clinical problems were observed. Functional properties of the isolated variant are described.

Structural and functional studies of hemoglobin Poissy alpha 2 beta 2(56) (D7) Gly----Arg and 86 (F2) Ala----Pro.

Hemoglobin Poissy alpha 2 beta 2(56) (D7) Gly----Arg and 86 (F2) Ala----Pro, is a new variant of the beta chain with two substitutions within the second exon of the corresponding gene. The electrophoretic mobilities are identical to those of Hb Hamadan alpha 2 beta 2(56) (D7) Gly----Arg as is the fingerprint of the tryptic hydrolysate of the two abnormal beta chains. The second substitution beta 86 Ala----Pro was detected by high-pressure liquid chromatography. Hb Poissy has a threefold increase in oxygen affinity with low Hill coefficient and diminished Bohr effect, which are restored to normal upon addition of 2,3-bisphosphoglycerate. Since the functional properties of Hb Hamadan (beta 56 Gly----Arg) have been described as normal, the abnormal function of Hb Poissy may be attributed to the beta 86 (F2) Ala----Pro substitution. Hb Poissy exhibits a mild instability and a greater reactivity of the thiol groups of the beta 93 (F9) Cys residues in the deoxy form than does Hb A. The oxidation rate of Hb Poissy is biphasic indicating a large inequivalence between the alpha and beta hemes. Thereafter NMR studies demonstrated that the beta 86 Ala----Pro substitution produces a displacement of the F helix closer to the heme plane and a large increase in the dynamic fluctuations of the tertiary structure on the proximal side of the beta hemes. These results lead to the conclusion that the beta 86 Ala----Pro substitution produces a destabilization of the F helix extending downwards to the FG corner and altering both the beta hemes and the alpha 1 beta 2 contacts.

Hemoglobin Roseau-Pointe a Pitre alpha 2 beta 2(90) (F6) Glu----Gly: a new hemoglobin variant with slight instability and low oxygen affinity.

A Dominican neonate carrying a new abnormal hemoglobin, hemoglobin Roseau Pointe-à-Pitre alpha 2 beta 2(90)(F6) Glu----Gly, was detected in Guadeloupe during application of a cord blood screening program. This variant behaved in isoelectrofocusing as an Hb D, and displayed instability and low whole blood oxygen affinity. In the affected family it was present, either isolated, or in association with a beta+ thalassemia trait.

Hemoglobin kenitra alpha 2 beta 2 69 (E13) Gly----Arg. A new beta variant of elevated expression associated with alpha-thalassemia, found in a Moroccan woman.

Hemoglobin Kenitra is a new variant of the beta chain alpha 2 beta 2 69 (E13) Gly----Arg which does not produce any clinical symptoms. It is a slow-moving hemoglobin with a distinctive pattern of electrophoretic mobilities. The stability test was negative. Oxygen affinity studies were not performed. It was found in association with alpha-thalassemia and microcytosis, but paradoxically a high expression of the variant (55%) was observed.

[Abnormal hemoglobins identified in Martinique]. / Hémoglobines anormales identifiées à la Martinique.

Epidemiologic programs in Martinique during the last 10 years and particularly the last 5, have allowed the determination of the Hb S, Hb C, beta thalassemia traits frequencies. A number of rare variants have been detected during the course of these screening programs. Many of these Hb variants have been analysed at the structural level. For some of them a pathologic interaction with Hb S is observed (Hb D Punjab, Hb O Arab...), and the use of electrophoretic mobilities obtained with the reference samples provides the basis of a rapid, highly probable presumptive identification and then, a useful tool, when for example genetic counselling is necessary.

Hb Marseille [alpha 2 beta 2 N methionyl-2 (NA2) His----Pro]: a new beta chain variant having an extended N-terminus.

A new abnormal hemoglobin was found in a diabetic Maltese woman by citrate agar electrophoresis. This variant was undetectable by isoelectric focusing. No hematological abnormalities were observed. The structural analysis included isolation of the abnormal beta chain, high pressure liquid chromatography of the corresponding tryptic peptides and then microsequencing of the abnormal T1. These procedures revealed a double abnormality: the presence of a methionyl residue extending the NH2 terminus and a histidine to proline substitution in position NA2.

Structural study of hemoglobin Hazebrouck, beta 38(C4)Thr----Pro. A new abnormal hemoglobin with instability and low oxygen affinity.

A new beta-variant has been detected and structurally defined in a French male, with a life-long history of hemolytic anemia. This variant is moderately unstable and has a low oxygen affinity. The abnormal hemoglobin was not detected by standard electrophoretic procedures. It moved slightly slower than Hb A during isoelectric focusing (IEF). Two minor fractions were also seen; the first migrated just cathodal to Hb F, as did partially oxidized Hb A or hemichrome derivatives of some unstable hemoglobins; the second in the position of free alpha-chains. The abnormal beta-chain was readily separated from both beta A- and alpha A-chains by acid-urea-Triton globin chain electrophoresis. Structural study was conducted simultaneously by fingerprinting and high-performance liquid chromatography (HPLC) of tryptic peptides. A new mutation beta 38(C4)Thr----Pro was found, which was named Hb Hazebrouck.