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At least 199 records · Page 11Linked to original sources
PubMed2006

Hb Bleuland [alpha108(G15)Thr-->Asn, ACC-->AAC (alpha2)]: a new abnormal hemoglobin associated with a mild alpha-thalassemia phenotype.

We report a new structural defect of the alpha2-globin chain, not detectable on high performance liquid chromatography (HPLC) or electrophoresis, characterized in a 12-year-old boy of Surinamese-Hindustani origin. The child was suspected to be a carrier of alpha-thalassemia (thal) because of microcytic hypochromic parameters in the absence of iron depletion. Gap-polymerase chain reaction (gap-PCR) revealed only normal fragments in the proband, and the pattern of a -alpha4.2 (leftward) deletion in his father and sister. Direct sequencing of the alpha-globin genes revealed an ACC-->AAC transversion at codon 108 of the alpha2-globin gene in the proband, in his mother and in a younger sister. The new mutation predicts a Thr -->Asn amino acid substitution at the corresponding residue. Threonine, a covalent binder with an R-active OH group, situated in the G helix of the alpha-globin chain, is involved in alpha1beta1 contacts. Asparagine, being an equally covalent binder but with a different R-active H2N-C=O group, could make the mutated chain less suitable for tetramer cooperation. Alternatively, an absent or reduced interaction with the alpha hemoglobin (Hb) stabilizing protein (AHSP) could lead to loss of alpha chains. Hb Bleuland is the first mutation described at codon 108 and is therefore interesting in regard to the possible effects and genetic risk. The nearest variant, Hb Suan-Dok [alpha109(G16)Leu -->Arg, CTG-->CGG (alpha2)] was originally observed in a Thai patient affected with Hb H, in combination with an alpha0-thal allele. The same Hb Suan-Dok mutation, recently described in our laboratory in a carrier of African ancestry, was also not detectable as a protein and presented with an alpha-thal phenotype similar to Hb Bleuland.

Adolescent↗
PubMed2001

Abnormal hemoglobins: laboratory methods.

Laboratory methods allowing the detection and characterization of hemoglobin variants are reviewed. Protein chemistry techniques such as isoelectrofocusing, electrophoreses under various experimental conditions, cation exchange and reversed phase high performance liquid chromatography, are the most frequently used for the detection of variants. When associated with a few additional data they may lead to a presumptive diagnosis. DNA studies are also developed in many laboratories. Final identification of a variant may be achieved either by molecular biology techniques or by protein sequence analysis in which mass spectrometry now occupies a key position.

Chemistry Techniques, Analytical↗
PubMed1976

Mapping of several abnormal hemoglobins by horizontal polyacrylamide gel isoelectric focusing.

The relative mobilities of serveral human hemoglobin variants were studied by use of an isoelectric focusing method in a thin-layer horizontal polyacrylamide gel. The technic is described in detail and a preliminary mapping of these variants is presented. It appears that thin-layer gel isoelectric focusing is a method that is rapid, highly reproducible and easily applicable in laboratories concerned with the study of hemoglobinopathies.

Amino Acid Sequence↗
PubMed1977

Radioimmunoassay for abnormal hemoglobins.

A sensitive and specific radioimmunoassay has been developed for the identification or quantification of the human hemoglobin variants S, C, D-Los Angeles, E, G Philadelphia, Russ, O Arab, Beograd, J Paris I, G San Jose, Q Iran, Korle Bu, and F Malta I. In the immunoassay, monospecific antibody preparations are used which recognize the single amino acid substitution in the variant polypeptide chail and do not cross-react with normal hemoglobins or hemoglobin variants containing a different amino acid exchange at the same position.

Amino Acid Sequence↗