1/15. Hb Sitia [beta128(H6)Ala-->Val]: an unstable variant with a substitution in the alpha1beta1 interface.Hb Sitia [beta128(H6)Ala-->Val] was found in a Greek female with slightly reduced red blood cell indices. The abnormal hemoglobin was indistinguishable from Hb A by electrophoresis but eluted after Hb A on cation exchange high performance liquid chromatography. dna sequence analysis revealed a GCT-->GTT mutation at codon 128, which is predicted to encode an Ala-->Val substitution. This was confirmed by mass spectrometry analyses of the beta-globin chain. Since alanine at beta128(H6) interacts with several amino acids of the alpha1beta1 contact, its replacement by a larger residue results in a mild instability of the molecule and slight modifications of the oxygen binding properties.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
2/15. Hb Mont Saint Aignan [beta128(H6)Ala-->Pro]: a new unstable variant leading to chronic microcytic anemia.Hb Mont Saint-Aignan [beta128(H6)Ala-->Pro] is a mildly unstable variant, associated with hemolytic anemia, marked microcytosis and increased alpha/beta biosynthetic ratio (1.55 versus 1.1 /- 0.1 in the control). The abnormal chain was isolated by selective precipitation with isopropanol and the structural modification determined by protein chemistry methods (reversed phase high performance liquid chromatography and mass spectrometry). Possible mechanisms underlying the beta( )-thalassemia-like expression of this variant are discussed.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
3/15. Molecular characterization of Hb D-Ibadan [beta87(F3)Thr-->Lys] in combination with Hb S [beta6(A3)Glu-->Val] and with beta -Thalassemia: report of two cases.Hb D-Ibadan [beta87(F3)Thr-->Lys] is a common variant in the Nigerian population, which has been reported in association with Hb S [beta6(A3)Glu-->Val] and with beta-thalassemia. Unlike the Hb S/Hb D-los angeles [beta121(GH4)Glu-->Gln] combination, compound heterozygosity for Hb D-Ibadan and Hb S does not result in a sickling disorder. We report the first case of a combination of Hb D-Ibadan with beta -thalassemia, and the first observation of Hb S/Hb D-Ibadan in the African-American population. In both cases, the characterization of Hb D-Ibadan was achieved by sequencing of the genomic dna. Although protein based methods such as isoelec-trofocusing and high performance liquid chromatography may suggest that the "D-like" variant is different from Hb D-los angeles, the definitive identification of the variant by structural analysis or molecular genetic methods should be undertaken, particularly in newborn screening programs when the variant is found in combination with Hb S.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
4/15. Hb Leslie, an unstable hemoglobin due to deletion of glutaminyl residue beta 131 (H9) occurring in association with beta0-thalassemia, HbC, and HbS.A new unstable hemoglobin, Hb Leslie, has been observed in three generations of a georgia family. The propositus, a 42-yr-old black veteran with hemolytic anemia and splenomegaly, has a hemoglobin variant with an electrophoretic mobility similar to that of hemoglobin F. The variant comprises about 85% of the total hemoglobin and was isolated by chromatography. Chemical analysis has identified the abnormality as a deletion of the glutaminyl residue in position 131 (H9) of the beta-chain. Deletion of this critical residue which participates in the alpha1beta1 contact causes decreased stability of the hemoglobin without significant changes in functional properties or morphologic abnormalities in the erythrocyte. family studies revealed hemoglobin Leslie occurring in combination with beta0-thalassemia, HbS, and HbC. All persons with the various Hb Leslie combinations, including the propositus, have no clinical manifestations other than anemia. In some the anemia is fully compensated. There is no history of drug-associated hemolysis.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
5/15. Failure of microchromatographic measurement of fetal hemoglobin in beta zero thalassemia-hereditary persistence of fetal hemoglobin.We report microchromatographic measurement of fetal hemoglobin (HbF) proportions in a 36-year-old African-American multigravida woman. At 34 weeks she delivered a 630-g male infant who subsequently did well. Hemoglobin electrophoresis of the hemolysate revealed nearly 100% HbF without HbA, an extremely unusual naturally occurring sample. family studies revealed a combination of hereditary persistence of fetal hemoglobin (HPFH) and beta zero-thalassemia minor. Southern blot technique confirmed heterozygous alpha 2 thalassemia and HPFH but failed to identify the beta thalassemic lesion. The absence of HbA and the very high amounts of HbF led us to measure HbF by several methods to confirm the accuracy of microchromatography of HbF at values approaching 100%. HPLC revealed a 14% F1 suggestive of microchromatographic underestimation due to glycated HbF. We conclude that cation-exchange microchromatography and the Betke method of alkali denaturation underestimate HbF values as they approach 100% and do not recommend these procedures in this rare situation.- - - - - - - - - - ranking = 2keywords = chromatography (Clic here for more details about this article) |
6/15. Laboratory diagnosis of a compound heterozygosity for Hb Hekinan [alpha27(B8) Glu-Asp] and a deletional alpha-thalassaemia 2 in thailand.We report the haematological and molecular characterization of a previously undescribed condition of compound heterozygosity for haemoglobin (Hb) Hekinan [alpha27(B8) Glu-Asp] and a deletional alpha-thalassaemia 2 detected in a Thai individual. Hb analysis demonstrated that although this Hb variant co-migrates with Hb A on cellulose acetate electrophoresis and cation-exchange high-performance liquid chromatography (HPLC), the HPLC procedure using a weak cation-exchange material with polyaspartic acid could clearly differentiate the two Hb. The variant could then be confirmed using the polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) analysis of the amplified alpha1-globin gene.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
7/15. HbQ-india in a Sindhi family: an uncommon hemoglobin variant.Hemoglobin Q-india is a very rare alpha-chain structural variant caused by the mutation AAG-->GAG (Asp-->His) in the position of codon 64 of the alpha1 gene. Usually it presents in the heterozygous form with electrophoretic mobility in the position of hemoglobin S (HbS) at alkaline pH along with the double bands of HbA2. High-performance liquid chromatography (HPLC) retention time of 4.76 minutes for this abnormal Hb variant identifies it to be HbQ-india. Only isolated case reports exist in literature to describe this rare entity. On cellulose acetate electrophoresis at alkaline pH, the HbQ band can easily be misinterpreted as HbS or HbD if careful screening of the patient for sickle cell with solubility test or sickling test is not done and the abnormal HbA2 band is overlooked. We report a case and emphasize the importance of careful screening with electrophoresis and HPLC in the diagnosis of this rare condition- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
8/15. Molecular and hematological characterization of hemoglobin hope/hemoglobin e and hemoglobin hope/alpha-thalassemia 2 in Thai patients.We report the hematological and molecular characterization of compound heterozygosity for hemoglobin (Hb) hope/Hb E and double heterozygosity for Hb hope/ alpha-thalassemia 2 found in 2 unrelated Thai individuals. The first proband presented with slight anemia and mild hypochromic microcytosis. Routine cellulose acetate Hb electrophoresis at pH 8.6 revealed in addition to Hb E another variant migrating slightly more anodic to Hb A. On cation exchange high-pressure liquid chromatography, the variant was eluted in the amount of 60.9% after Hb E The same abnormal Hb was found in a second family in which the proband and her younger sister were both double heterozygotes for this Hb variant and deletional alpha-thalassemia 2, whereas an older sister was a pure carrier of the variant. The amounts of this variant were found to be 34.9%, 35.4%, and 38.3% in the proband, her younger sister, and her older sister, respectively. Direct dna sequencing of the amplified beta-globin genes of both probands identified the GGT (Gly)-GAT (Asp) mutation at codon 136 corresponding to Hb hope. beta-Globin gene haplotype analysis demonstrated that all the Thai betaHope genes were associated with the same haplotype, ( - - - - ), indicating a single origin of this variant in thailand. A simple method based on allele-specific polymerase chain reaction for accurate diagnosis of the Hb hope is described.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
9/15. Differential diagnosis of adult hemoglobin a, F, and S conditions. A case of G gamma-beta( )-hereditary persistence of fetal hemoglobin.Hemoglobin (Hb) S/beta( )-thalassemia is a hemoglobinopathy of variable but potentially severe clinical course. The condition is usually confirmed by the presence of a microcytic anemia and elevated levels of Hbs S, F, and A2 by electrophoresis. However, other less common disorders of Hb structure and synthesis may exhibit laboratory findings that mimic Hb S/beta( )-thalassemia but have a more favorable prognosis. We present a case occurring in a man with clinical and laboratory features that were suggestive of Hb S/beta( )-thalassemia but with normocythemia. Although nonmicrocytic variants of beta( )-thalassemia, including concomitant nutritional deficiencies, were considered, high-pressure liquid chromatography revealed nearly all of the patient's fetal Hb to contain only G gamma chains. This pattern is most consistent with the rate but clinically benign condition of Hb S/G gamma-beta( )-hereditary persistence of fetal Hb, a nondeletional type of hereditary persistence of fetal Hb. We discuss a diagnostic approach to adult Hb A, F, and S conditions, including thalassemias and thalassemia-like syndromes.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
10/15. Hb Isehara (or Hb Redondo) [beta 92 (F8) HisAsn]: an unstable variant with a proximal histidine substitution at the heme contact. A 50-year-old Japanese female patient was found to have hemolytic anemia. Isoelectrofocusing of her hemolysate revealed two abnormal hemoglobin bands, one of which was very close to the Hb A2 band, and the other between the Hb A2 and Hb F bands. CM-cellulose column chromatography of the globin prepared from the abnormal hemoglobin showed that the abnormal chain eluted faster than the normal beta and delta chains; the beta X chain, however, did not separate from the normal beta chain in urea cellulose acetate electrophoresis. An instability test of the patient's hemolysate revealed the presence of an unstable component. Structural analysis of the abnormal beta chain indicated that the histidine residue at beta 92(F8) was replaced by an asparagine or aspartic acid residue. dna amplified by polymerase chain reaction was sequenced by the dideoxy method. The nucleotide sequence of the beta 92 codon was AAC instead of CAC, suggesting that the amino acid substitution corresponded to His Asn, which is the same as is found in Hb Redondo or beta 92(F8)His Asn Asp.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
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