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Summary Haemoglobin (Hb) H disease and HbH disease with co‐inherited HbE mutation are the most prevalent forms of α‐thalassaemia in Southeast Asia. Data were limited when comparing clinical phenotypes between these two patient groups. We conducted a Thai multicentre study and enrolled 588 patients [median (IQR) age 13.0 (6.7–20.3) years], including those with deletional HbH disease with (n = 47) and without (n = 187) co‐inherited HbE mutation and non‐deletional HbH disease with (n = 101) and without (n = 253) co‐inherited HbE mutation. Patients with HbH disease with co‐inherited HbE mutation suffered more severe manifestations than those without. This observation was more pronounced in patients with non‐deletional HbH disease. A greater proportion of patients with non‐deletional HbH disease with co‐inherited HbE mutation (43.6%) eventually required regular transfusions compared to those without (30.4%, p = 0.019). Among those with non‐deletional HbH disease who did not require regular transfusions, Hb levels were lower in patients with co‐inherited HbE mutation [8.1 (7.2–8.6) vs. 8.8 (8.2–9.5) g/dL, p < 0.001]. Among patients requiring regular transfusions who underwent splenectomy, 11/12 patients with non‐deletional HbH disease stopped transfusion compared with 1/3 in non‐deletional HbH disease with co‐inherited HbE mutation group (p = 0.024). These findings provide insights for the clinical monitoring and management of HbH disease in the region. [ABSTRACT FROM AUTHOR]

Alpha thalassemia is a genetic disease characterized by insufficient expression or definite absence of the α-globin chain. Three large deletions (thal-1; 26.5 kb or MedII, 20.5 kb and 17.4 kb or MedI) and two small deletions (thal-2; 4.2 kb and 3.7 kb) have been characterized in our country. In addition, two different PolyA mutations (PA1: AATAAA>AATAAG and PA2: AATAAA>AATGA) on the α2-globin gene (αα/αPAα), 5nt deletion (αα/α5ntα), and unstable Hb variant (CD 59; GGC→GAC) synthesized by the α1-globin gene (αα/ααCD59) have been reported. More than ten different combinations of α-thal-1 and α-thal-2 (- -/-α) or HbH genotypes with point mutations (--/αPAα or --/ααCD59) were determined. In this study, which was carried out in Çukurova region, it is aimed to emphasize the importance of giving genetic counseling to families with alpha thalassemia carriers and to determine genotype combinations. DNA was isolated from blood samples taken from 5 children and their families who were admitted to Çukurova University Balcalı Hospital and diagnosed with severe anemia (Hb <9, MCV <70) as a result of blood count HbA2 values were measured by HPLC. Gene deletions were determined by multiplex PCR. When two families with two children are compared, the fact that the second child of the family who receives genetic counseling service is a carrier and the second child of the family who does not receive genetic counseling service is patient highlights the importance of genetic counseling service. [ABSTRACT FROM AUTHOR]

Background: The main function of hemoglobin (Hb) is to transport oxygen in the circulation. It is among the most highly studied proteins due to its roles in physiology and disease, and most of our understanding derives from comparative research. There is great diversity in Hb gene evolution in placental mammals, mostly in the repertoire and regulation of the β-globin subunits. Dogs are an ideal model in which to study Hb genes because: 1) they are members of Laurasiatheria, our closest relatives outside of Euarchontoglires (including primates, rodents and rabbits), 2) dog breeds are isolated populations with their own Hb-associated genetics and diseases, and 3) their high level of health care allows for development of biomedical investigation and translation. Results: We established that dogs have a complement of five α and five β-globin genes, all of which can be detected as spliced mRNA in adults. Strikingly, HBD, the allegedly-unnecessary adult β-globin protein in humans, is the primary adult β-globin in dogs and other carnivores; moreover, dogs have two active copies of the HBD gene. In contrast, the dominant adult β-globin of humans, HBB, has high sequence divergence and is expressed at markedly lower levels in dogs. We also showed that canine HBD and HBB genes are complex chimeras that resulted from multiple gene conversion events between them. Lastly, we showed that the strongest signal of evolutionary selection in a high-altitude breed, the Bernese Mountain Dog, lies in a haplotype block that spans the β-globin locus. Conclusions: We report the first molecular genetic characterization of Hb genes in dogs. We found important distinctions between adult β-globin expression in carnivores compared to other members of Laurasiatheria. Our findings are also likely to raise new questions about the significance of human HBD. The comparative genomics of dog hemoglobin genes sets the stage for diverse research and translation. [ABSTRACT FROM AUTHOR]

Adult haemoglobin (Hb) is made up of two α and two β subunits. Mutations that reduce expression of the α- or β-globin genes lead to the conditions α- or β-thalassaemia, respectively. Whilst both conditions are characterized by anaemia of variable severity, other details of their pathophysiology are different, in part owing to the greater stability of the β chains that is conferred through β self-association. In contrast, α subunits interact weakly, and in the absence of stabilizing quaternary interactions the α chain (α) is prone to haem loss and denaturation. The molecular contacts that confer weak self-association of α have not been determined previously. Here, the first structure of an α2 homodimer is reported in complex with one domain of the Hb receptor from Staphylococcus aureus. The α2 dimer interface has a highly unusual, approximately linear, arrangement of four His side chains within hydrogen-bonding distance of each other. Some interactions present in the α1β1 dimer interface of native Hb are preserved in the α2 dimer. However, a marked asymmetry is observed in the α2 interface, suggesting that steric factors limit the number of stabilizing interactions that can form simultaneously across the interface. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the utility of isoelectric focusing electrophoresis (IEF) for identifying patients with α-thalassemia, which results from the deletion of 1 or more of the α-globin genes. Methods: Samples were selected based on their hemoglobin H (HbH) concentration observed using IEF. The samples were analyzed for the most common α-globin gene deletions using molecular analysis. Results: α-Globin gene deletions corresponding to α-thalassemia trait or silent carrier were observed in all samples with the HbH less than 2% phenotype. The genotypes of the specimens with HbH greater than 5% were consistent with HbH disease, while the wild-type phenotype control samples showed a wild-type genotype. Conclusions: Low concentrations of HbH can be detected in a patient with 1 or 2 α-gene deletions using IEF. [ABSTRACT FROM AUTHOR]

Introduction Coinheritance of α-thalassemia influences the clinical and hematological phenotypes of β-hemoglobinopathies (β-thalassemia and sickle cell disease) and when present together in significant frequency within a population, a spectrum of clinical forms is observed. Precise molecular characterization of α-thalassemia is important in understanding their disease-modifying role in β-hemoglobinopathies and for diagnostic purposes. Patients and methods Because currently used approaches are labor/cost-intensive, time-consuming, error-prone in certain genotype combinations and not applicable for large epidemiological screening, we developed a systematic stepwise strategy to overcome these difficulties. We successfully applied this to characterize the α-globin gene status in 150 Omani cord blood samples with Hb Barts and 32 patients with HbH disease. Results We observed a good correlation between α-globin genotypes and level of Hb Bart's with the Hb Bart's levels significantly higher in both deletional and non-deletional α-globin genotypes. The most common α-globin genotype in Hb H cases was α TSaudiα/α TSaudiα ( n = 16; 50%) followed by −α3.7/- MED ( n = 10; 31%). This approach detects also the α-globin gene triplication as exemplified by the study of a family where the β-globin gene defect failed to explain the β-thalassemia intermedia phenotype. Conclusion Molecular characterization of α-thalassemia is complex due to high sequence homology between the duplicated α-globin genes and to the existence of a variety of gene rearrangements (small and large deletions of various sizes) and punctual substitutions (non-deletional alleles). The novelty of our strategy resides, not in the individual technical steps per se but in the reasoned sequential order of their use taking into consideration the hematological phenotype as well. [ABSTRACT FROM AUTHOR]

We report a case of hemolytic anemia that was subsequently identified to be a case of α-thalassaemia harboring the common rightward 3.7 kb deletion/HbH. The diagnosis was based on sequential analyses using BioRad D10 HPLC, Alkaline gel electrophoresis, GPO α THAL-IC strips and the identification of the specific genetic lesion using an α Globin reverse dot blot hybridization assay. Supravital stain of RBCs helped in identifying classical HbH inclusions. In a background of a variable clinical presentation, lack of definitive hematological markers, and general under-diagnosis of α-thalassaemias we have used this case to highlight the features and sequence of techniques involved in identifying and characterizing an α-globin chain mutation, starting from a diffuse clinical history and presentation up to the identification of a specific genetic lesion involved. [ABSTRACT FROM AUTHOR]

Abstract: Globin genes, which encode the protein subunits of hemoglobin (Hb), are organized in two different gene clusters and present a coordinated and differential pattern of expression during development. Concerning the human α-globin gene cluster (located at chromosome region 16p13.3), four upstream highly conserved elements known as multispecies conserved sequences (MCS-R1-4) or DNase I hypersensitive sites (HSs) are implicated in the long-range regulation of downstream gene expression. However, only the absence of the MCS-R2 site (HS-40) has proven to drastically downregulate the expression of those genes, and consequently, it has been regarded as the major and crucial distal regulatory element. In this study, Multiplex Ligation-dependent Probe Amplification was used to screen for deletions in the telomeric region of the short arm of chromosome 16, in an attempt to explain the α-thalassemia or the HbH disease present in a group of Portuguese patients. We report four novel and five uncommon deletions that remove the α-globin distal regulatory elements and/or the complete α-globin gene cluster. Interestingly, one of them occurred de novo and removes all HSs except HS-10, while other eliminates only the HS-40 site, the latter being replaced by the insertion of a 39 nucleotide orphan sequence. Our results demonstrate that HS-10 alone does not significantly enhance the α-globin gene expression. The absence of HS-40 in homozygosity, found in a patient with Hb H disease, strongly downregulates the expression of α-globin genes but it is not associated with a complete absence of α-globin chain production. The study of naturally occurring deletions in this region is of great interest to understand the role of each upstream regulatory element in the native human erythroid environment. [ABSTRACT FROM AUTHOR]

This study describes a new molecular condition in the α 2 -globin gene ( HBA2) found in six unrelated families from Southern Italy (Campania and Sicily). This new double mutant form of haemoglobin is called Hb Southern Italy and originated from the coexistence of two known mutations occurring in the same globin gene, HBA2 26 G→A (Hb Caserta) and HBA2 130 G→C (Hb Sun Prairie). Hb Sun Prairie was originally observed in Indian patients in either the homozygous state, with severe hemolytic anemia, and in the heterozygous state with microcytosis, or in asymptomatic cases as an α-thalassemia carrier phenotype. Hb Caserta was observed for the first time in a Casertian family (South Italy) that displayed a slowmigrating haemoglobin upon investigation. We report the clinical phenotype and molecular study of this new double mutant form of haemoglobin in heterozygous and homozygous subjects, as well as in association with α° delectional thalassemia. [ABSTRACT FROM AUTHOR]

Human bleomycin hydrolase (hBH) catalyzes deamidation of the anticancer drug bleomycins (BLM). This enzyme is involved in BLM detoxification and drug resistance. Herein, we report the putative BLM-binding site and catalytic mechanism of hBH. The crystal structures and biochemical studies suggest that hBH cleaves its C-terminal residue without significant preference for the type of amino acid, and therefore can accordingly accommodate the β-aminoalanine amide moiety of BLM for deamidation. Interestingly, hBH is capable of switching from a cysteine protease to a serine protease that is unable to cleave the secondary amide of hBH C-terminus but reacts with the primary amide of BLMs., (© 2022 Wiley-VCH GmbH.)

The article discusses the thalassaemia deletions of the Sry-related protein (SOX8) that is not associated with ATR-16 in an HbH family from Brazil. It presents a schematic presentation of 2 Mb of the 16p13-3 telomeric region and scatter plot showing the ratios of multiplex ligation dependent probe amplification (MLPA) probes in chronological order. It states that the application of MLPA as a screening method in the detection of unknown thalassaemia deletions could be a helpful tool.

Alpha (α)-thalassemia (thal) is a common single-gene genetic disease in southern China, which may cause Hb Bart's hydrops fetalis and Hb H disease. In α + thal, one of the α genes is inactivated, due either to a deletion (-α) such as the rightward deletion (-α 3.7 ) and leftward deletion (-α 4.2 ), or to another form of mutation (α T α), such as the Hb Constant Spring (α CS α). In this study, three probands from three Chinese families in Fujian Province showed HbH disease traits, while their common genotypes of α-thal were -- SEA /-- SEA at a routine analysis. In doing so, we further found a rare 27.6 kb deletion on the α-globin gene cluster in the three probands by MLPA (multiplex ligation-dependent probe amplification) and Sanger DNA sequencing, and its breakpoints were detected to lie between coordinates 9079 and 36718 with a total of 27,640 nucleotides deletion. The accurate genotypes of the three probands were -α 27.6 /-- SEA , which led to a very mild hemoglobin H (HbH) disease phenotype with low MCV, MCH, and HbA2 levels. Phenotypic analysis on the heterozygote of this deletion revealed it as α + mutation. In conclusion, we report a rare α-thal deletion, -α 27.6 , in three Chinese families from Fujian Province. Our study extends the spectrum of the α-thal mutation in the Chinese population. It is necessary to increase awareness of the rare α-thal mutation and to increase its detection, which will prove valuable in genetic counseling and prenatal diagnosis in Fujian Province., Competing Interests: None., (IJCEP Copyright © 2018.)