Hemoglobin Hamadan or alpha 2 beta 256(D7)Gly----Arg in a Turkish family.
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Biomedical subjects
Publications and source records attributed to J B Wilson.
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The presence of the alpha-globin frameshift mutant, Hb Wayne, in three generations of a second family is described. The data include a hematological evaluation of the four heterozygotes, structural characterization of the variant, the use of HPLC for the separation of tryptic and chymotryptic peptides, functional analyses of the isolated variant showing high affinity for oxygen and the (near) absence of a Bohr effect, and alpha chain gene organization analyses with restriction endonuclease technology suggesting that the Hb Wayne heterozygote has a full complement of four alpha globin genes.
Hb Cordele, which has an Asp----Ala substitution at position 47 (CE5) of the alpha chain, was discovered in Black twins living in Cordele, Georgia. The structure of this variant was elucidated through analyses of tryptic peptides of the alpha chain which were isolated by high performance liquid chromatography. At birth, Hb Cordele accounted for about 21-23% of total hemoglobin, and for 30.4% in one of the babies at age 3.5 months. Hb Cordele has a normal oxygen affinity, but is mildly unstable at 60 degrees C. Some of its properties have been compared with those of Hb Kokura (alpha 47 Asp----Gly), Hb Hasharon (alpha 47 Asp----His), and Hb Arya (alpha 47 Asp----Asn). Studies on an adult carrier of Hb Cordele were not possible.
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Structural studies and quantitative analyses were conducted on the hemoglobin of 55 newborn babies. Seven alpha chain variants (G-Philadelphia, Montgomery, Inkster, I-Philadelphia, Matsue-Oki, Winnipeg, and O-Indonesia) were present in 26 heterozygous newborns (17 black, eight Caucasian, and one Indonesian). The relative amount of the alpha X containing abnormal Hb F of the Hb G-Philadelphia and Hb Winnipeg babies was less than observed in heterozygous adults, which may indicate a decreased rate of assembly of the alpha X-gamma dimer over that of the alpha X-beta dimer. Of the 29 newborns with gamma chain variants, 16 were Caucasian babies; of these 15 had a Hb A gamma F-Hull heterozygosity and one a Hb G gamma F-Marietta heterozygosity. Six black babies were heterozygous for Hb A gamma F-Texas-I and six for Hb G gamma F-Port Royal. One Japanese baby had a heterozygosity for A gamma F-Iwata and a second was heterozygous for A gamma TF-Yamaguchi. Quantitative analyses of the isolated normal Hb Fo as well as an evaluation of the relative amounts of the Hb Fx in the red cell lysates gave data useful for a speculation of the genetic condition in each of these babies. It was concluded that the babies with the Hbs F-Texas-I, F-Iwata, F-Hull, and F-Marietta were simple heterozygotes with either the G gamma x A gamma/G gamma x A gamma X or the G gamma x A gamma/G gamma X x A gamma genic arrangement. The babies with Hb F-Port Royal had a G gamma x G gamma X/G gamma x A gamma arrangement, which may result from a (to be determined) gene conversion. The newborn baby with Hb F-Yamaguchi has the G gamma x A gamma x/A gamma T-X.-. genic arrangement, suggesting the presence of three distinctly different gamma chain genes of which one, the A gamma T-X gene, produces an A gamma chain (with threonyl at position gamma 75 and an Asn at position gamma 80) at a level usually seen for G gamma rather than A gamma chains. These studies were greatly facilitated by the use of high pressure liquid chromatographic methods.
The gamma chain compositions of the fetal hemoglobins of 2453 newborn babies from East Asian countries (1350 babies), from Italy, Yugoslavia, Bulgaria, and Georgia (417 Caucasian babies), and 686 black babies from Georgia were determined by high pressure liquid chromatography. Unusual results for a limited number of babies were confirmed by chemical analyses, and were evaluated further by family studies. Statistical analyses indicated high gene frequencies for the A gamma T chain in Italian (f = 0.237), Yugoslavian and Bulgarian (f = 0.238), and white Georgia babies (f = 0.224), a lower frequency in Japan (f = 0.178), and India (f = 0.173), and particularly in mainland China (f = 0.079). The A gamma T gene frequency in normal (AA) Black babies was 0.102. When a beta S or beta C mutation was also present this frequency was greatly decreased, particularly in babies with the AC condition (f = 0.036). These results suggest the near absence of the A gamma T mutation on the chromosome also carrying the beta C determinant. Most babies had the expected G gamma values which vary between 60 and 80%, but several (mainly black) babies had higher values (between 80 and 90%), while one normal black baby had a G gamma value of (nearly) 100%. This condition may be a form of A gamma +1-thalassemia and has been discussed in detail elsewhere (Blood 58:491-500, 1981). Thirty-five clinically normal (mainly Chinese, Indian, and Japanese) babies had G gamma values of about 40%. Twenty-six babies had A gamma I values of about 60%, while the remaining nine babies had A gamma T and A gamma I chains in a ratio of either 1 to 2 or 1 to 1. Two additional newborns did not produce any G gamma chains, but had only A gamma I chains or A gamma T chains. Family studies failed to indicate a specific hematological abnormality. These unusual ratios between the G gamma and A gamma (either A gamma I or A gamma T) chains have led to speculations regarding possible genetic abnormalities present in these infants.
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A slowly moving variant of Hb A2 was present in a 25-year-old Spanish woman and her mother, and was found to have a Glu replaced by Val substitution at position 121 of the delta chain. The variant was unstable and precipitated gradually during anion exchange chromatography. The effect of this substitution on the stability of the protein is apparently more severe for Hb A2 than for Hb A because Hb Beograd (beta 121 Glu replaced by Val) has normal physicochemical properties.
A fast-moving alpha chain abnormal hemoglobin (Hb J) was observed in a black teenager from southern Georgia. Its quantity, i.e. the sum of Hb J and Hb J2, was 23.8%. Its presence did not cause any hematological or clinical abnormalities. Tryptic peptides from a digest of the alpha-J chain were separated by HPLC. Amino acid analysis of these peptides and sequence analysis of the abnormal T-2,3 nonapeptide identified a Lys leads to Asn substitution at position alpha 11(A9).
A new HPLC procedure is described for the separation and quantitation of minor human Hb variants. The cation exchanger, Synchropak CM 300, is a silica support with a bonded polymeric coating of carboxylic acid residues. The chromatogram is developed with 0.03M Bis-Tris-KCN buffers, pH 6.40, and a Na-acetate gradient increasing from 0 to 0.1125M. As many as 11 minor Hbs (including Hb A2) can be isolated. Some of these have been identified through rechromatography of the minor Hb zones obtained by Bio-Rex-70 chromatography. Quantitation of Hb A1c and Hb A2 is readily accomplished. Hb F0 and an unidentified minor Hb often observed in red cells of alcoholics co-chromatograph with Hb A1c. The method has been applied to blood samples of 10 normal adults, 13 diabetic patients, and nine alcoholic subjects. An excellent correlation exists between the Hb A1c percentages and the levels of Hb A1 determined by microcolumn chromatography. Some other minor Hbs, identified as components 9 and 10, which are (at least in part) Hb A0 with glucose attached to the alpha chains, are present in increased amounts in the blood of diabetic patients and others may be observed in patients who subject themselves to (severe) alcohol abuse. It is suggested that the new procedure is well-suited for detailed studies of the minor Hbs in patients with various abnormalities in carbohydrate metabolism.
This paper reports the results of the analyses of 17 different Hb variants which were observed in 37 families. High pressure liquid chromatography (HPLC) was used to separate tryptic and thermolytic peptides of globin chains. The double microsequencing technique can successfully be used for sequencing small or larger peptides.
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A new cation-exchange HPLC method is described for the separation and quantitation of abnormal human Hbs. The method makes use of Synchropak CM 300, a silica support with carboxylic acid residues, and Bis-Tris-KCN-Na-acetate developers and allows a completion of the chromatogram in 50 to 90 min depending on the sample to be analyzed. Specific chromatographic profiles have been obtained for several beta, alpha, and delta chain variants. The method is useful not only for the quantitation of Hb F and Hb A2 (except in the presence of Hb E) but also provides easy differentiation between simple heterozygotes for a specific abnormality and persons with the same abnormality together with an additional beta-thalassemia heterozygosity. Probably the most important application of the new procedure is in the quantitation of Hb A and the beta chain variants S, C, O-Arab, and E in cord blood samples, thus facilitating the diagnosis of conditions such as AE, EE, AS, SS, S-beta +thal, AC, CC, C-beta +thal, SC, and SO in newborn babies.