Hb Paksé [(alpha2) codon 142 (TAA-->TAT or Term-->Tyr)J in Thai patients with EAbart's disease and Hb H Disease

Hb Paksé is caused by an alpha2-globin gene termination codon mutation, TAA-->TAT or Term-->Tyr, initially described in a Laotian family. We now report for the first time that the same mutation has been found in 14 Thai patients, seven with EABart's disease, four with Hb H disease, and three with alpha-thalassemia trait who were initially diagnosed as having Hb Constant Spring (Hb CS; alpha2-globin gene termination codon mutation TAA-->CAA or Term-->Gln). Co-inheritance of this mutation with alpha-thalassemia-1 (SEA type) leads to Hb H disease (hereafter designated as Hb H-Paksé disease) and to a complex thalassemia syndrome, namely EABart's-Paksé disease. Hematological data of these patients were compared with those of classical Hb H-CS and the EABart's patients. To facilitate epidemiological and diagnostic screening of Hb Paksé, a simple assay procedure based on allele specific polymerase chain reaction (PCR) amplifications was developed and validated. Using this allele specific PCR as a screening method, five additional individuals with Hb Paksé were found among 71 Thai subjects previously thought to have Hb CS.     

Haemoglobin (Hb) G-Philadelphia, Hb Stanleyville-II, Hb G-Norfolk, Hb Matsue-Oki and Hb Mizushi can form a panel of α-chain variants that overlap in their phenotype: the novel use of StyI to screen for Hb G-Philadelphia

Introduction: Haemoglobin (Hb) G‐Philadelphia mutation is a common alpha‐globin chain variant [α68(E17)Asn > Lys]. Combined high performance liquid chromatography (HPLC) and isoelectric focusing (IEF) can be used in a presumptive diagnosis of Hb G‐Philadelphia, but there are other α‐chain variants with a similar phenotype that cannot be excluded. Our aim was to develop a novel StyI restriction enzyme assay to diagnose the common Hb G‐Philadelphia mutation and to identify any other variants with a similar phenotype by DNA sequencing. Methods: Thirty‐one cases given a presumptive diagnosis as Hb G‐Philadelphia by HPLC and IEF were subjected to DNA analysis by restriction enzyme digestion using StyI. Negative cases were then subjected to DNA sequencing. Results: Twenty‐two cases (78.6%) of 28 cases amplified were tested positive for Hb G‐Philadelphia by StyI restriction digestion. Sequencing of the six negative cases revealed two cases of Hb G‐Philadelphia with C→A mutation in codon 68 in α2 globin gene, plus one case each of Hb G‐Norfolk Hb Stanleyville‐II, Hb Matsue‐Oki and Hb Mizushi. Conclusion: A novel StyI restriction enzyme can be used to confirm the commonest type of Hb G‐Philadelphia. DNA sequencing identified four other α‐chain variants with a similar HPLC and IEF phenotype.     

Complex Interaction of Hb Q-Thailand (HBA1: c.223G>C) with β-Thalassemia/Hb E (HBB: c.79G>A) Disease

Hb Q-Thailand [α74(EF3)Asp→His (α1), GAC>CAC, HBA1: c.223G>C] is an abnormal hemoglobin (Hb) frequently found in Thailand and Southeast Asian countries. The association of the α^Q-Thailand allele with other globin gene disorders has important implications in diagnosis. Here, we report how to diagnose the coinheritance of Hb Q-Thailand with β-thalassemia (β-thal)/Hb E disease in four Thai samples from high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) testing results. Understanding of the HPLC chromatogram and CE electropherogram patterns of this complex mutation is important for interpretation of testing results and providing genetic counseling.     

Compound heterozygosity for Hb Korle-Bu (β<Superscript>73</Superscript>; Asp-Asn) and Hb E (β<Superscript>26</Superscript>; Glu-Lys) with a 3.7-kb deletional α-thalassemia in Thai patients

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.     

Identification of three novel Hb F variants: Hb F-Hayward [Gγ1(NA1)Gly→Asp, GGT>GAT], Hb F-Chori-I [AγT16(A13)Gly→Asp, GGC>GAC] and Hb F-Chori-II [AγI29(B11)Gly→Glu, GGA>GAA

Three new γ-globin chain mutations were identified in four newborn samples referred to the Hemoglobinopathy Reference Laboratory at the Children's Hospital & Research Center Oakland, Oakland, CA, USA, for diagnostic testing. The variants were characterized by sequencing of amplified γ-globin genes. These three novel variants have been named Hb F-Hayward [(G)γ1(NA1)Gly→Asp, GGT>GAT], Hb F-Chori-I [(A)γ(T)16(A13)Gly→Asp, GGC>GAC] and Hb F-Chori-II [(A)γ(I)29(B11)Gly→Glu, GGA>GAA], respectively. No functional studies could be performed.     

Comparison between capillary electrophoresis and high performance liquid chromatography for detection and quantification of Hb constant spring [Hb CS; α142, Term→Gln (TAA>CAA IN α2)

Hb Constant Spring [Hb CS; α142, Term→Gln (TAA>CAA in α2)] is often missed by routine laboratory testing since its mRNA as well as gene product are unstable and presented at a low level in peripheral blood. This study aimed to analyze the efficacy of capillary electrophoresis (CE) and high performance liquid chromatography (HPLC) for detecting and quantifying Hb CS in 19 heterozygotes and 14 homozygotes with Hb CS as well as 10 Hb H-CS disease subjects who were detected by molecular analysis. In the CE electrophoregram, Hb CS was seen at zone 2 and was observed in all samples, while the chromatogram of Hb CS peaks was found in 26.32% heterozygotes, 42.86% homozygotes and 90% Hb H-CS disease subjects, respectively. In addition, the Hb CS levels in each group of subjects quantified by CE were significantly higher than those quantified by HPLC. Based on the CE method, the lowest Hb CS level was found in the heterozygotes, whereas the highest level was found in the Hb H-CS disease patients. Therefore, the CE method was superior to the HPLC method for detecting Hb CS. Furthermore, the level of Hb CS quantified by CE proved useful in screening heterozygotes and homozygotes with Hb CS as well as Hb H-CS disease.     

Hb Dartmouth (HBA2: c.200T>C): An α2-Globin Gene Associated with Hb H Disease in One Homozygous Patient

Abstract

Hb H (β4) disease is caused by deletion or inactivation of three out of four α-globin genes. A high incidence of Hb H disease has been reported all over the world. There is a wide spectrum of phenotypic presentations, from clinically asymptomatic to having significant hepatosplenomegaly and requiring occasional or even regular blood transfusions, even more severe anemia, Hb Bart’s (γ4) hydrops fetalis syndrome that can cause death in the affected fetuses late in gestation. We here present a case who was diagnosed with Hb H disease that represents a new genotype for this hereditary disorder. Hb Dartmouth is a variant caused by a missense mutation at codon 66 of the α2-globin gene (HBA2: c.200T>C), resulting in the substitution of leucine by proline. We here emphasize the importance of this point mutation involving Hb H disease and also the necessity for prenatal diagnosis (PND) for those who carry this point mutation in the heterozygous state.     

Molecular characterization and origins of Hb Constant Spring and Hb Paksé in Southeast Asian populations

Hemoglobin Constant Spring (Hb CS) and Hb Paksé, two abnormal Hbs characterized by elongated α-globin chains resulting from mutations of the termination codon in the α2-globin gene, are the most prevalent nondeletional α-thalassemias in Southeast Asia. To determine the origins of these two variants in the region, we have determined α-globin gene haplotypes associated with these two variants on 120 Thai, eight Cambodian, and six Laos alleles, and the results were compared with those reported previously for the Chinese and Mediterranean. Five haplotypes were found to be associated with 131 α^CS genes examined, whereas a single haplotype was linked to all the α^Paksé genes in these Southeast Asian populations. All the α^CS haplotypes differed from those of the Mediterranean, but one of them was similar to a Chinese α^CS gene reported previously. It is concluded that there are multiple origins of the α^CS and a single origin of the α^Paksé mutations in Southeast Asia. Hematological findings confirm the mild thalassemia intermedia phenotypes for pure homozygous Hb CS and homozygous Hb CS with Hb E heterozygote and Hb E homozygote. The appearance of Hb CS peak by high-performance liquid chromatography analysis indicates the ability to form a tetrameric Hb molecule between the α^CS and β^E chains, leading to a novel derivative with similar characteristics to Hb CS.     

Hb A2-Tianhe (HBD: c.323G>A): First Report in a Chinese Family with Normal Hb A2-β-Thalassemia Trait

Coinheritance of δ-globin variants along with β-globin gene defects can interfere with correct diagnosis of β-thalassemia (β-thal) trait. In this report, we present the coinheritance of a δ-globin variant, Hb A₂-Tianhe [δ107(G9)Gly→Asp; HBD: c.323G>A] and a heterozygous β-thal in a Chinese individual with microcytosis, hypochromia and a normal Hb A₂ level.     

肝硬化患者外周血Hb变化的意义

1996年9月~2006年5月,我们对780例肝硬化患者的外周血Hb含量进行检测,以探讨肝硬化患者Hb变化的临床意义。资料与方法:本文780例肝硬化患者(观察组),男511例、女269例,年龄(54.2±11.8)岁。均符合1990年全国肝硬化学术会议制定的诊断标准,排除合并消化道出血者。其中60例病情恶     

青岛地区大学生Hb水平检测及意义

采用血液自动分析仪对青岛地区112例大学生进行血红蛋白（Hb）、红细胞计数、红细胞压积的检测。发现男性Hb平均水平（144．15g／L）明显高于女性（125．47g／L）;按WHO标准有1例男性和6例女性诊断为贫血,贫血患病率为6．2％。认为合理膳食和良好的饮食习惯对预防缺铁性贫血十分重要。     

Three new alpha-globin variants: Hb Itapira [alpha30(B11)Glu-->Val (alpha1)], Hb Bom Jesus Da Lapa [alpha30(B11)Glu-->Ala (alpha1)] and Hb Boa Esperança [alpha16(A14)Lys-->Thr (alpha2)

Three novel alpha-globin variants were found during a screening program for hemoglobinopathies in blood donors at the UNICAMP Hematology and Hemotherapy Center, Campinas, State of S?o Paulo, Southeastern Brazil. They were named for the town of origin of the carrier as Hb Itapira [alpha30(B11)Glu-->Val], Hb Bom Jesus da Lapa [alpha30(B11)Glu-->Ala] and Hb Boa Esperan?a [alpha16(A14)Lys-->Thr]. Hb Itapira, like Hb Bom Jesus da Lapa, shows an electrophoretic mobility similar to that of Hb S [beta6(A3)GluVal, GAG-->GTG] at alkaline pH; it is associated with a triplicate alpha-globin allele (alphaalphaalpha(anti 3.7)) and corresponds to only 5.5% of the total hemoglobin (Hb). Hb Boa Esperan?a, found in two different individuals, moves faster than Hb A and exhibits an abnormal functional performance.     

Homozygosity for HBA1: c.179G > A: Hb Adana in an Infant

Hb Adana (HBA1: c.179G?>?A) is a very rare, unstable form of α-globin variant that results from deficient synthesis of functional α chains. We present a 2-month-old boy with hypochromic microcytic anemia, and remarkable anisocytosis, target cells and basophilic stippling on his peripheral blood smear. α-Globin gene analysis of the patient determined homozygosity for HBA1: c.179G?>?A, a mutation known as Hb Adana. On his follow-up visit, hemoglobin (Hb) levels were stable at 9.0–9.5?g/dL and mean corpuscular volume (MCV) was 62.2–62.5?fL without the need for a blood transfusion. Clinical and hematological findings of our case were comparable to Hb H (β4) or β-thalassemia intermedia (β-TI)-like phenotypes, despite the fact that he carried an α1 gene mutation. Heterozygosity for the HBA1: c.179G?>?A mutation may also lead to microcytosis only as seen in his parents. According to our current knowledge, this is the first described case with homozygosity for the Hb Adana mutation, carried on the α1 gene. The relatively mild presentation of the case highlights the milder phenotypic consequences of nondeletional α mutations in the α1 vs. the α2 gene.     

Hb Sarrebourg [β131(H9)Gln→Arg, CAG>CGG] in Turkey

We describe Hb Sarrebourg [β131(H9)Gln→Arg, CAG>CGG] in four heterozygous members of a Turkish family. It was associated with iron deficiency in the proband.     

β-Globin Gene Cluster Haplotypes of Hb D-Punjab

The interaction of the nondeletional α-thalassemia (α-thal) mutations with the Southeast Asian double α-globin gene deletion results in nondeletional Hb H (β4) disease. Hb Constant Spring (Hb CS, α142, TAA>CAA at α2) and Hb Quong Sze [Hb QS, α125, CTG>CCG (α2)] are the most common nondeletional α-thalassemias in the Chinese population. These α-globin structural variants are unstable and undetectable by routine hemoglobin (Hb) electrophoresis. The amount of Hb Bart’s (γ4) in the cord blood of newborns correlates with the number of α-globin genes that are deleted. We determined the quantity of Hb Bart’s in cord blood at birth with the Sebia CapillaryS electrophoresis system. Using Hb Bart’s levels at 0.1-2.5% as a cut-off range for nondeletional α-thal diagnosis, we detected 154 individuals in 6,525 newborns. Of the 154 samples, 12 were found to be Hb CS carriers, 10 Hb QS carriers, and one Hb Westmead [α122, CAC>CAG (α2)] carrier. We present the first report of the prevalence of Hb QS in our population.     

A Mosaic Expression of a Hb J-Amiens (HBB: c.54G > T; p.Lys18Asn) and its Interference with Hb A1c Analysis

Abstract

We report the case of a 56-year-old Caucasian woman in whom hemoglobinopathy screening was triggered following an aberrant Hb A_1c analysis. Preliminary diagnosis of the hemoglobin (Hb) variant was obtained through cation exchange high performance liquid chromatography (HPLC) and gel electrophoresis. DNA analysis confirmed the presence of Hb J-Amiens [β17(A14)Lys→Asn; HBB: c.[54G?>?C or 54G?>?T)]. However, an unbalanced ratio between wild type and mutant signal after direct sequencing and a lower than expected percentage of this Hb variant led to the suggestion of a mosaic expression. Furthermore, different methods [capillary zone electrophoresis (CZE), cation exchange HPLC and boronate affinity] were tested to study the possible interference of this variant with Hb A_1c measurements. These investigations showed a clinically relevant difference between the methods tested. Hb A_1c analysis may lead to the discovery of new Hb variants or mosaicism for previously described Hb variants. This may have genetic consequences for the offspring of carriers and brings about the question of partner testing.