Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019045 (hemoglobinopathies)
 2,704 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have developed a murine monoclonal antibody (mAb) specific for the delta chain of hemoglobin (Hb) A2 that does not cross-react with alpha, beta, or gamma chains. The mAb reacted with Hb P-Nilotic (beta delta hybrid), but not with Hb Lepore-Boston (delta beta hybrid), indicating an epitope consisting of positions 116 (Arg) and 117 (Asn) or 125 (Gln) and 126 (Met) of the delta chain. By using this antibody, we have established a simple and rapid enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of Hb A2 in adult, cord, and fetal hemolysates. We analyzed 70 adult, 8 newborn, and 19 fetal hemolysates from normal subjects and those with various hemoglobinopathies. The mean percentage of Hb A2 was 2.5 for normal adults, 5.4 for beta thalassemic (beta thal) heterozygotes, and less than 0.1% in beta thal fetal samples. We were able to distinguish and characterize certain phenotypes of beta thal patients such as beta thal heterozygotes, beta 0 thal homozygotes, and C beta 0 thal, and C beta + thal double heterozygotes with the aid of this and other mAbs we have generated. This technique is a valuable addition to current methods for the diagnosis of beta thal based on quantification of Hb A2.
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PMID:Application of a monoclonal antibody specific for the delta chain of hemoglobin A2 in the diagnosis of beta thalassemia. 195 20

In the course of our newborn screening program for the presence of hemoglobinopathies in the Republic of Macedonia, we have detected a new G gamma chain variant with a Lys-->Asn or AAG-->AAC substitution at codon 104. The variant was found in a blood sample from a healthy baby boy of Macedonian nationality. The abnormal chain was quantitated at 32.4% of the total gamma chains by reversed phase high performance liquid chromatography. The characterization of the variant was by sequence analysis of polymerase chain reaction-amplified DNA. The presence of the mutation in the mother was confirmed by Hph I restriction enzyme digestion of the polymerase chain reaction-amplified DNA fragment. Although the mutated G is the last nucleotide of exon 2 and part of the donor splice site sequence of the second intervening sequence of the G gamma gene, it appears that the splicing of the mRNA in this variant is not altered.
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PMID:Hb F-Macedonia-II [G gamma 104(G6)Lys-->Asn]: a new gamma chain variant. 771 41

Abnormal human hemoglobins (HBs) with amino acid substitutions in the alpha 1 beta 2 interface have very high oxygen affinity and greatly reduced cooperativity in O2 binding compared to normal human Hb. In such abnormal Hbs with mutations at position beta 99, the intersubunit hydrogen bonds between Asp-beta 99 and Tyr-alpha 42 and between Asp-beta 99 and Asn-alpha 97 are broken, thus destabilizing the deoxyquaternary structure of these Hbs. A molecular dynamics method has been used to design compensatory amino acid substitutions in these Hbs that can restore their allosteric properties. We have designed a compensatory mutation in a naturally occurring mutant Hb, Hb Kempsey (Asp-beta 99-->Asn), and have produced it using our Escherichia coli expression plasmid pHE2. We have determined the O2 binding properties of this recombinant double mutant Hb, Hb(Asp-beta 99-->Asn and Tyr-alpha 42-->Asp) and have used 1H NMR spectroscopy to investigate the tertiary structures around the heme groups and the quaternary structure in the alpha 1 beta 2 subunit interface. Our results clearly show that the Tyr-alpha 42-->Asp replacement can substantially compensate for the functional defect of Hb Kempsey caused by the Asp-beta 99-->Asn substitution. The structural and functional information derived from this recombinant Hb provides insights into the structural basis of allosterism and the design of compensatory amino acid substitutions to restore the functional properties of other abnormal HBs associated with hemoglobinopathies.
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PMID:Restoring allosterism with compensatory mutations in hemoglobin. 797 99

Two new fetal hemoglobin variants affecting the Ggamma chain are reported. Hb F-Clamart was found during investigation of a French newborn who presented with a mild microcytemia. The second variant was found during neonatal screening for hemoglobinopathies of 30,000 babies from a population-at-risk living in the Paris region. It was named Hb F-Ouled Rabah because its structural modification and ethnic distribution is similar to that of Hb D-Ouled Rabah [beta19(B1)Asn-->Lys]. Hb F-Ouled Rabah is clinically silent and occurs at a frequency of ca. 0.1% in newborns originating from Maghreb. Structural characterization of both variants was done by protein chemistry methods, including amino acids analysis and mass spectrometry.
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PMID:Two new Ggamma chain variants: Hb F-clamart [gamma17(A14)Lys-->Asn] and Hb F-Ouled Rabah [gamma19(B1)Asn-->Lys]. 1072 15

Hb Presbyterian is a variant hemoglobin that carries Lys at Asn-108 of beta-globin. This variant Lys(beta108) residue enhances the stability of Hb in the deoxy-state, conferring the low affinity for oxygen-binding in vitro. In the present study, we generated mutant mice carrying the Presbyterian mutation (Asn(beta108)-->Lys) at the beta-globin locus by a targeted knock-in strategy. Heterozygous mice showed the expression of Hb Presbyterian in 27.7% of total peripheral blood without any hematological abnormalities, which well mimicked human cases. On the other hand, homozygous mice exclusively expressed Hb Presbyterian in 100% of peripheral blood associated with hemolytic anemia, Heinz body formation, and splenomegaly. Hb Presbyterian showed instability in an in vitro precipitation assay. Erythrocytes from homozygous mice showed a shortened life span when transfused into wild-type mice, confirming that the knocked-in mutation of Lys(beta108) caused hemolysis in homozygous mice. This is the first report on the hemolytic anemia of unstable hemoglobin in an animal model. These results confirm the notion that the higher ratio of an unstable variant beta-globin chain in erythrocytes triggers the pathological precipitation and induces hemolysis in abnormal hemoglobinopathies.
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PMID:Model mice for Presbyterian hemoglobinopathy (Asn(beta108)-->Lys) confer hemolytic anemia with altered oxygen affinity and instability of Hb. 1212 75

Hemoglobin (Hb) Korle-Bu (beta73; Asp-Asn) is the most frequent of the rare beta-chain variants in the population of West Africa whereas Hb E (beta26; Glu-Lys) is common among the Southeast Asian population. We report a hitherto undescribed condition in which these two beta-chain variants co-segregate. The proband was a 19-year-old Thai pregnant woman in her second trimester of pregnancy who visited our thalassemia screening unit. Cellulose acetate electrophoresis and high-performance liquid chromatography (HPLC) analysis of Hb detected one abnormal Hb in addition to the Hb E. Analysis of DNA sequences revealed a GAT-AAT mutation at codon 73 in trans to a GAG-AAG mutation at codon 26 of the beta-globin gene. Polymerase chain reaction (PCR) analysis of the alpha-globin gene cluster of the patient detected a 3.7-kb deletional alpha-thalassemia 2. Family study identified that her mother had the same genotype and her father was a simple Hb E carrier. The hematological data of these unusual cases of hemoglobinopathy are presented and compared with a simple heterozygote for Hb Korle-Bu found in another unrelated Thai family. beta-Globin gene haplotype linked to the Thai beta(Korle-Bu) and a simple DNA assay based on allele-specific PCR for rapid diagnosis of Hb Korle-Bu are also described.
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PMID:Compound heterozygosity for Hb Korle-Bu (beta(73); Asp-Asn) and Hb E (beta(26); Glu-Lys) with a 3.7-kb deletional alpha-thalassemia in Thai patients. 1218 10

A Thai family with a complex thalassemia syndrome caused by alpha- and beta-globin defects is described. The proband was a 14-year-old boy who had chronic hypochromic microcytic anemia. Hemoglobin (Hb) and DNA analyses demonstrated that he carried Hb Beijing [alpha16(A14)Lys-->Asn], Hb E [beta26(B8)Glu-->Lys] and alpha-thalassemia-1 (alpha-thal-1). Interaction of the alphaBeijing with the betaE globin chains in the proband leads to a new Hb variant, namely Hb E Beijing with different characteristics to both Hb E and Hb Beijing. Family studies showed that his father carried Hb Beijing and Hb E, whereas his mother was a simple alpha-thal-1 carrier. The genotype-phenotype relationship observed in this Thai family with complex hemoglobinopathies is presented and a simple DNA assay based on allele specific polymerase chain reaction (ASPCR) for detection of Hb Beijing is described.
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PMID:Thalassemia intermedia associated with complex interaction of Hb Beijing [alpha16(A14)Lys-->Asn] and Hb E [beta26(B8)Glu-->Lys] with a deletional alpha-thalassemia-1 in a Thai family. 1576 59

Here, we report a rare coincidence of heterozygous hemoglobinopathy (Hb) Stanleyville II and severe pernicious anemia due to autoimmune gastritis. Hb Stanleyville II is characterized by a single base exchange (AAC-->AAA) resulting in a substitution Asn --> Lys at position 78 of hemoglobin alpha2-chain. Under normal conditions this hemoglobinopathy does not cause any symptoms even if present as homozygous variant. However, in our case diagnosis of pernicious anemia was hampered by the absence of typical erythrocytic macrocytosis and hyperchromasia. In addition, interpretation of bone marrow smears was difficult as characteristic findings for pernicious anemia were little pronounced. All known reasons for the absence of typical cytomorphologic signs in pernicious anemia as underlying iron deficiency and thalassemia could be excluded.
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PMID:Cytomorphologic signs of severe pernicious anemia obscured in a patient with heterozygous hemoglobin Stanleyville II. 1768 Aug 15

We describe a case of compound heterozygosity for hemoglobin C (beta6 Glu-->Lys) and hemoglobin Korle-Bu (beta73 Asp-->Asn). To our knowledge, this is the third case report of this unusual hemoglobin genotype, and the first to integrate data from cation exchange high-performance liquid chromatography, hemoglobin electrophoresis, and beta-globin gene sequencing. The principal hematological finding in our case was microcytosis without significant anemia. The previous case reports of this hemoglobinopathy also describe microcytosis, with varying degrees of hemolytic anemia. Given the relative gene frequencies of hemoglobins C and Korle-Bu, the occurrence of this compound-heterozygous genotype should be anticipated in people of African ancestry.
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PMID:Compound heterozygosity for hemoglobin C and hemoglobin Korle-Bu. 1881 84

A pregnant Thai woman with mild hypochromic microcytic anemia caused by alpha- and beta- globin defects is described. The proband was a 26-year-old pregnant woman discovered through our ongoing thalassemia screening program. Initial hemoglobin (Hb) high performance liquid chromatography (HPLC) analysis revealed a homozygosity for an unknown variant at the D window, inconsistent with results of family analyses. Further Hb analysis using automated capillary zone electrophoresis identified that the proband was in fact a compound heterozygote for Hb E [beta26(B8)Glu-->Lys, GAG>AAG] and another beta chain variant. DNA analysis demonstrated that she carried the Hb Korle-Bu mutation [beta73(E17)Asp-->Asn (GAT>AAT)] in trans to the Hb E and an alpha-thalassemia-1 (alpha-thal-1) with the Southeast Asian (- -(SEA)) deletion. Family studies identified that her father and sister were double heterozygotes for Hb Korle-Bu and alpha-thal-1, whereas her mother was a double heterozygote for Hb E/Hb Constant Spring [Hb CS; alpha142, Term-->Gln (TAA>CAA in alpha2)]. The genotype-phenotype relationship observed in this Thai family with complex hemoglobinopathies and methods for characterization are presented.
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PMID:Complex interaction of Hb E [beta26(B8)Glu-->Lys], Hb Korle-Bu [beta73(E17)Asp-->Asn] and a deletional alpha-thalassemia-1 in pregnancy. 1995 98


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