Alpha-thalassaemia

A large cohort of Hb H disease in northeast Thailand: A molecular revisited, diverse genetic interactions and identification of a novel mutation

BACKGROUND AND AIMS

To update the molecular characteristics of α-thalassemia in northeast Thailand, the molecular basis and genetic interactions of Hb H disease were examined in a large cohort of patients.

MATERIALS AND METHODS

A study was done on 1,170 subjects with Hb H disease and various genetic interactions encountered during 2009-2023. Hb and DNA analyses were carried out.

RESULTS

As many as 40 genotypes with several known, previously undescribed, and novel mutations were observed. These included 698 subjects (59.8 %) of Hb H disease, 357 (30.6 %) with EABart's disease, 63 (5.4 %) with EEBart's disease, 18 (1.7 %) with abnormal Hbs, 17 (1.5 %) with β-thalassemia, and 4 (0.4 %) with EFBart's or EFABart's disease. The molecular basis of 13 subjects (1.1 %) remains unknown. The α0-thalassemia included --SEA (n = 1,139, 97.4 %) and --THAI (n = 21, 1.8 %). Two rare mutations were identified in 3 subjects (0.3 %) with --SA and --CR deletions. For α+-thalassemia, -α3.7 kb del (n = 626, 53.5 %), Hb Constant Spring (n = 415, 35.5 %), -α4.2 kb del (n = 44, 3.8 %), Hb Paksé (n = 36, 3.1 %), and Hb Q-Thailand (n = 19, 1.6 %), were detected. Ten rarer α+-thalassemia were identified, including a novel mutation, namely the Hb Chumphae (HBA2:c.32T>A). The Hb H-Lansing-Ramathibodi, Hb H-Jax, and Hb H-Chumphae are hitherto undescribed in this region. PCR-based diagnostic methods for these α-thalassemia defects were described.

CONCLUSIONS

This study confirms the diverse heterogeneity and genetic interactions causing Hb H disease in northeast Thailand. The results should prove useful for laboratory diagnosis and genetic counseling of this genetic disorder in the region.

Machine Learning-Based Prediction of Hemoglobinopathies Using Complete Blood Count Data

BACKGROUND

Hemoglobinopathies, the most common inherited blood disorder, are frequently underdiagnosed. Early identification of carriers is important for genetic counseling of couples at risk. The aim of this study was to develop and validate a novel machine learning model on a multicenter data set, covering a wide spectrum of hemoglobinopathies based on routine complete blood count (CBC) testing.

METHODS

Hemoglobinopathy test results from 10 322 adults were extracted retrospectively from 8 Dutch laboratories. eXtreme Gradient Boosting (XGB) and logistic regression models were developed to differentiate negative from positive hemoglobinopathy cases, using 7 routine CBC parameters. External validation was conducted on a data set from an independent Dutch laboratory, with an additional external validation on a Spanish data set (n = 2629) specifically for differentiating thalassemia from iron deficiency anemia (IDA).

RESULTS

The XGB and logistic regression models achieved an area under the receiver operating characteristic (AUROC) of 0.88 and 0.84, respectively, in distinguishing negative from positive hemoglobinopathy cases in the independent external validation set. Subclass analysis showed that the XGB model reached an AUROC of 0.97 for β-thalassemia, 0.98 for α0-thalassemia, 0.95 for homozygous α+-thalassemia, 0.78 for heterozygous α+-thalassemia, and 0.94 for the structural hemoglobin variants Hemoglobin C, Hemoglobin D, Hemoglobin E. Both models attained AUROCs of 0.95 in differentiating IDA from thalassemia.

CONCLUSIONS

Both the XGB and logistic regression model demonstrate high accuracy in predicting a broad range of hemoglobinopathies and are effective in differentiating hemoglobinopathies from IDA. Integration of these models into the laboratory information system facilitates automated hemoglobinopathy detection using routine CBC parameters.

A rare hemoglobinopathy duo: Hb Adana×Hb SEA in a 1-year-old patient - a case report and a brief literature review

Introduction and importance

Alpha thalassemia, resulting from nondeletional mutations, typically presents a more severe clinical manifestation compared to deletional mutations. Severe outcomes, such as hydrops fetalis, are associated with two specific nondeletional mutations. Therefore, DNA-based investigation is crucial for suspected carriers exhibiting subtle hematological abnormalities to facilitate proper diagnosis and effective family counseling.

Case presentation

In this report, the authors describe a phenotypically normal 1-year-old girl with a rare and unique alpha-thalassemia genotype due to the presence of Hb Adana, a nondeletional alpha-chain mutation compounded with Hb SEA, an alpha-globin gene deletion.

Clinical discussion

Mutations determine the clinical manifestations of alpha-thalassemia. DNA testing is recommended for suspected carriers with relatively small hematological abnormalities, for precise diagnosis and family counseling. To provide clinicians with a reference for diagnostic assessment, the authors established a genotype-phenotype correlations based on reported cases of Hb Adana following an exhaustive literature review. Being interested in determining which ethnicities and genotypes are associated with a higher risk of complications, including hydrops fetalis and transfusion dependence, the authors formalized a diagnostic evaluation guide and a guide for early screening to improve outcomes.

Conclusion

Precise genetic evaluation is important for the diagnosis of alpha thalassemia. Hematologists play a critical role in managing these disorders, understanding genotype-phenotype correlations, and highlighting the significance of genetic counseling for high-risk patients. Extensive studies on these various genophenotypes are required to improve the diagnosis and prognosis of such medical conditions and advocate preventative strategies.

Current Status of Molecular Diagnosis of Hereditary Hemolytic Anemia in Korea

Hereditary hemolytic anemia (HHA) is considered a group of rare hematological diseases in Korea, primarily because of its unique ethnic characteristics and diagnostic challenges. Recently, the prevalence of HHA has increased in Korea, reflecting the increasing number of international marriages and increased awareness of the disease. In particular, the diagnosis of red blood cell (RBC) enzymopathy experienced a resurgence, given the advances in diagnostic techniques. In 2007, the RBC Disorder Working Party of the Korean Society of Hematology developed the Korean Standard Operating Procedure for the Diagnosis of Hereditary Hemolytic Anemia, which has been continuously updated since then. The latest Korean clinical practice guidelines for diagnosing HHA recommends performing next-generation sequencing as a preliminary step before analyzing RBC membrane proteins and enzymes. Recent breakthroughs in molecular genetic testing methods, particularly next-generation sequencing, are proving critical in identifying and providing insight into cases of HHA with previously unknown diagnoses. These innovative molecular genetic testing methods have now become important tools for the management and care planning of patients with HHA. This review aims to provide a comprehensive overview of recent advances in molecular genetic testing for the diagnosis of HHA, with particular emphasis on the Korean context.

Ancestry of the major long-range regulatory site of the α-globin genes in the Portuguese population with the common 3.7 kb α-thalassemia deletion

BACKGROUND

The α-Major Regulatory Element (α-MRE), also known as HS-40, is located upstream of the α-globin gene cluster and has a crucial role in the long-range regulation of the α-globin gene expression. This enhancer is polymorphic and several haplotypes were identified in different populations, with haplotype D almost exclusively found in African populations. The purpose of this research was to identify the HS-40 haplotype associated with the 3.7 kb α-thalassemia deletion (-α3.7del) in the Portuguese population, and determine its ancestry and influence on patients' hematological phenotype.

METHODS AND RESULTS

We selected 111 Portuguese individuals previously analyzed by Gap-PCR to detect the presence of the -α3.7del: 50 without the -α3.7del, 34 heterozygous and 27 homozygous for the -α3.7del. The HS-40 region was amplified by PCR followed by Sanger sequencing. Four HS-40 haplotypes were found (A to D). The distribution of HS-40 haplotypes and genotypes are significantly different between individuals with and without the -α3.7del, being haplotype D and genotype AD the most prevalent in patients with this deletion in homozygosity. Furthermore, multiple correspondence analysis revealed that individuals without the -α3.7del are grouped with other European populations, while samples with the -α3.7del are separated from these and found more closely related to the African population.

CONCLUSION

This study revealed for the first time an association of the HS-40 haplotype D with the -α3.7del in the Portuguese population, and its likely African ancestry. These results may have clinical importance as in vitro analysis of haplotype D showed a decrease in its enhancer activity on α-globin gene.

Base Editors-Mediated Gene Therapy in Hematopoietic Stem Cells for Hematologic Diseases

Base editors, developed from the CRISPR/Cas system, consist of components such as deaminase and Cas variants. Since their emergence in 2016, the precision, efficiency, and safety of base editors have been gradually optimized. The feasibility of using base editors in gene therapy has been demonstrated in several disease models. Compared with the CRISPR/Cas system, base editors have shown great potential in hematopoietic stem cells (HSCs) and HSC-based gene therapy, because they do not generate double-stranded breaks (DSBs) while achieving the precise realization of single-base substitutions. This precise editing mechanism allows for the permanent correction of genetic defects directly at their source within HSCs, thus promising a lasting therapeutic effect. Recent advances in base editors are expected to significantly increase the number of clinical trials for HSC-based gene therapies. In this review, we summarize the development and recent progress of DNA base editors, discuss their applications in HSC gene therapy, and highlight the prospects and challenges of future clinical stem cell therapies.

Severe Transfusion-Dependent Thalassemia in Compound Heterozygote Palestinian Siblings with Two α-Globin Gene Defects, Hb Taybe D HBA1: C.119_121delCCA Mutation and HBA2: C.*94A > G Mutation

Alpha and Beta Thalassemia are autosomal recessive anemias that cause significant morbidity and mortality worldwide, especially in the Middle East and North Africa (MENA) region where carrier rates reach up to 50%. We report the case of two siblings of Palestinian origin born who presented to our tertiary healthcare center for the management of severe transfusion dependent hemolytic anemia. Before presentation to our center, the siblings were screened for a-thalassemia using the Alpha-globin StripAssay. They were found to carry the α2 polyA-1 [AATAAA > AATAAG] mutation in the heterozygous form, which was insufficient to make a diagnosis. No pathogenic variants were detected on Sanger sequencing of the HBB gene. Full sequencing of the a-gene revealed compound heterozygous variants (HBA1:c.119_121delCCA and the previously detected HBA2:c.*+94A > G Poly A [A->G]) with trans inheritance. This report highlights the impact of non-deletional mutations on α-globin chain stability. The compound heterozygosity of a rare α-globin chain pathogenic variant with a polyadenylation mutation in the probands leads to clinically severe a-thalassemia. Due to the high carrier status, the identification of rare mutations through routine screening techniques in our populations may be insufficient. Ongoing collaboration among hematologists, medical geneticists, and counselors is crucial for phenotypic-genotypic correlation and assessment of adequate genetic testing schemes.

Αlpha-thalassemia: A practical overview

α-Thalassemia is an inherited blood disorder characterized by decreased synthesis of α-globin chains that results in an imbalance of α and β globin and thus varying degrees of ineffective erythropoiesis, decreased red blood cell (RBC) survival, chronic hemolytic anemia, and subsequent comorbidities. Clinical presentation varies depending on the genotype, ranging from a silent or mild carrier state to severe, transfusion-dependent or lethal disease. Management of patients with α-thalassemia is primarily supportive, addressing either symptoms (eg, RBC transfusions for anemia), complications of the disease, or its transfusion-dependence (eg, chelation therapy for iron overload). Several novel therapies are also in development, including curative gene manipulation techniques and disease modifying agents that target ineffective erythropoiesis and chronic hemolytic anemia. This review of α-thalassemia and its various manifestations provides practical information for clinicians who practice beyond those regions where it is found with high frequency.

Hematological Profile of Hb Adana Among High School Students in Northeast Peninsular Malaysia

Background Hb Adana is a non-deletional alpha (α)-thalassaemia variant resulting from mutations in α1- or α2-globin codon 59 (αCD59), leading to the production of unstable α-globin. Clinical manifestations can vary from silent carrier status to dependence on blood transfusions, hepatosplenomegaly, skeletal deformities, and spinal cord compression. Despite the significance of Hb Adana inheritance, studying this variant poses challenges due to the scarcity of molecular tests and the potential for routine diagnoses to be overlooked. This study aims to investigate the prevalence of Hb Adana among local high school students and assess the hematological parameters and hemoglobin analysis of Hb Adana in Malaysia. Methodology This retrospective study analyzed 13,721 blood samples collected from high school students participating in Malaysia's National Thalassaemia Screening Program at Hospital Raja Perempuan Zainab II (HRPZ II). Deletional α-thalassaemia was detected using multiplex gap-polymerase chain reaction (PCR), while common non-deletional α-thalassaemia was identified using multiplex amplification refractory mutation system (ARMS) PCR. Data were extracted from the HRPZ II database for analysis. Results Among the participants, 2327 individuals were found to have either common deletional (n=1037, 44.6%) or non-deletional (n=1290, 55.4%) α-thalassaemia. Hb Constant Spring was the most prevalent non-deletional α-thalassaemia, accounting for 53.03% of cases. Thirty-one participants (1.33%) exhibited αCD59α/αα, and one (0.04%) had αCD59α/-α3.7. Among the 32 subjects with Hb Adana, 87.5% were Malay, and 12.5% were Orang Asli. Additionally, seven cases of HbE/Hb Adana co-inheritance were identified. Hemoglobin levels in heterozygous Hb Adana individuals ranged from mild anemia to normal, between 95 g/L and 153 g/L. Mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were approximately 73 fL and 23 pg, respectively. Conclusion This study delineates the distribution of α-thalassaemia mutation patterns among high school students in Kelantan, Northeast Peninsular Malaysia. Our findings indicate that Hb Adana is rare in our region and co-inheritance with an α-gene deletion results in α+-thalassaemia and with HbE, α0-thalassaemia. All heterozygous Hb Adana individuals exhibited low MCVs and MCHs.

Severe Perinatal Presentations of Günther's Disease: Series of 20 Cases and Perspectives

(1) Background: Congenital erythropoietic porphyria (CEP), named Günther's disease, is a rare recessive type of porphyria, resulting from deficient uroporphyrinogen III synthase (UROS), the fourth enzyme of heme biosynthesis. The phenotype ranges from extremely severe perinatal onset, with life-threatening hemolytic anaemia, to mild or moderate cutaneous involvement in late-onset forms. This work reviewed the perinatal CEP cases recorded in France in order to analyse their various presentations and evolution. (2) Methods: Clinical and biological data were retrospectively collected through medical and published records. (3) Results: Twenty CEP cases, who presented with severe manifestations during perinatal period, were classified according to the main course of the disease: antenatal features, acute neonatal distress and postnatal diagnosis. Antenatal symptoms (seven patients) were mainly hydrops fetalis, hepatosplenomegaly, anemia, and malformations. Six of them died prematurely. Five babies showed acute neonatal distress, associated with severe anemia, thrombocytopenia, hepatosplenomegaly, liver dysfunction, and marked photosensitivity leading to diagnosis. The only two neonates who survived underwent hematopoietic stem cell transplantation (HSCT). Common features in post-natal diagnosis (eight patients) included hemolytic anemia, splenomegaly, skin sensitivity, and discoloured teeth and urine. All patients underwent HSCT, with success for six of them, but with fatal complications in two patients. The frequency of the missense variant named C73R is striking in antenatal and neonatal presentations, with 9/12 and 7/8 independent alleles, respectively. (4) Conclusions: The most recent cases in this series are remarkable, as they had a less fatal outcome than expected. Regular transfusions from the intrauterine period and early access to HSCT are the main objectives.

Diagnosis and screening of abnormal hemoglobins

Hemoglobin (Hb) abnormalities, such as thalassemia and structural Hb variants, are among the most prevalent inherited diseases and are associated with significant mortality and morbidity worldwide. However, there were not comprehensive reviews focusing on different clinical analytical techniques, research methods and artificial intelligence (AI) used in clinical screening and research on hemoglobinopathies. Hence the review offers a comprehensive summary of recent advancements and breakthroughs in the detection of aberrant Hbs, research methods and AI uses as well as the present restrictions anddifficulties in hemoglobinopathies. Recent advances in cation exchange high performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE), isoelectric focusing (IEF), flow cytometry, mass spectrometry (MS) and polymerase chain reaction (PCR) etc have allowed for the definitive detection by using advanced AIand portable point of care tests (POCT) integrating with smartphone microscopic classification, machine learning (ML) model, complete blood counts (CBC), imaging-based method, speedy immunoassay, and electrochemical-, microfluidic- and sensing-related platforms. In addition, to confirm and validate unidentified and novel Hbs, highly specialized genetic based techniques like PCR, reverse transcribed (RT)-PCR, DNA microarray, sequencing of genomic DNA, and sequencing of RT-PCR amplified globin cDNA of the gene of interest have been used. Hence, adequate utilization and improvement of available diagnostic and screening technologies are important for the control and management of hemoglobinopathies.

Super-enhancers include classical enhancers and facilitators to fully activate gene expression

Super-enhancers are compound regulatory elements that control expression of key cell identity genes. They recruit high levels of tissue-specific transcription factors and co-activators such as the Mediator complex and contact target gene promoters with high frequency. Most super-enhancers contain multiple constituent regulatory elements, but it is unclear whether these elements have distinct roles in activating target gene expression. Here, by rebuilding the endogenous multipartite α-globin super-enhancer, we show that it contains bioinformatically equivalent but functionally distinct element types: classical enhancers and facilitator elements. Facilitators have no intrinsic enhancer activity, yet in their absence, classical enhancers are unable to fully upregulate their target genes. Without facilitators, classical enhancers exhibit reduced Mediator recruitment, enhancer RNA transcription, and enhancer-promoter interactions. Facilitators are interchangeable but display functional hierarchy based on their position within a multipartite enhancer. Facilitators thus play an important role in potentiating the activity of classical enhancers and ensuring robust activation of target genes.

Identification of a novel 91.5 kb-deletion (αα)FJ in the α-globin gene cluster using single-molecule real-time (SMRT) sequencing

OBJECTIVES

To present a novel 91.5-kb deletion of the α-globin gene cluster (αα)FJ identified by genetic assay and prenatal diagnosis in a Chinese family.

SUBJECTS AND METHODS

The proband was a 34-year-old G3P1 (Gravida 3, Para 1) female at the gestational age of 21+ weeks with a history of an edematous fetus. A routine genetic assay (reverse dot blot hybridization, RDB) was performed to detect common thalassemia mutations. Multiplex ligation-dependent probe amplification (MLPA) and single-molecule real-time technology (SMRT) were used to detect rare thalassemia mutations.

RESULTS

The hematological phenotypes of the proband, her mother, elder sister, husband, daughter, and nephew were consistent with the phenotype of α-thalassemia trait. No mutations were found in these family members by RDB, except for the proband's husband who carried an α-globin gene deletion --SEA/αα. MLPA results showed that the proband and other α-thalassemia-suspected relatives had heterozygous deletions around the POLR3K-3-463nt, HS40-178nt, and HBA-HS40-382nt probes. The 5'-breakpoint was out of probe scope and could not be determined. SMRT was performed and a 91.5-kb deletion (NC_000016.10: g.39268_130758del) in the α-globin gene cluster (αα)FJ was identified in the proband and other suspected relatives, which could explain their phenotypes. At the proband's gestational age of 22+ weeks, an amniotic fluid sample was collected and analyzed. As only the 91.5-kb deletion (αα)FJ was identified in the fetus with RDB, MLPA, and SMRT. The proband was suggested to continue the pregnancy.

CONCLUSION

We first reported a 91.5-kb deletion (NC_000016.10: g.hg38-chr16:39268-_130758del) of the HS-40 region in the α-globin gene cluster (αα)FJ identified in a Chinese family. Since the HS-40 loss of heterozygosity in combination with the heterozygous deletion --SEA might result in Hb Bart's hydrops fetalis, routine genetic assay, and SMRT were recommended to individuals at risk for prenatal diagnosis.

Case report: Identification of a novel triplication of alpha-globin gene by the third-generation sequencing: pedigree analysis and genetic diagnosis

BACKGROUND

Thalassemia, a common autosomal hereditary blood disorder worldwide, mainly contains α- and β-thalassemia. The α-globin gene triplicates allele is harmless for carriers, but aggravates the phenotype of β-thalassemia. Therefore, it is particularly crucial to accurately detect the structural variants of α-globin gene clusters.

CASE REPORT

We reported a 28-year-old man, the proband, with microcytic hypochromic anemia. From pedigree analysis, his mother and sister had hypochromic microcytosis, and his father was normal. Genetic testing of thalassemia identified a novel α-globin gene triplicate named αααanti4.2del726bp (NC_000016.10:g.170769_174300dupinsAAAAAA) by third-generation sequencing (TGS) in the proband and his father, which was further validated by multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing. The genotypes of the proband's mother and sister were both -α3.7/αα compounded with heterozygous HBB:c.126_129delCTTT. They were categorized as silent α-thalassemia with co-inheritance of β-thalassemia trait. The proband's genotype additionally had the α-globin gene triplicates compared with his mother and sister, which increased the imbalance between α/β-globin, so the proband had more severe hematological parameters. The proband's wife was diagnosed as HBA2:c.427T > C heterozygosis, and his daughter had the novel α-globin gene triplicates compounded with HBA2:c.427T > C, therefore the girl might be asymptomatic.

CONCLUSION

The identification of the novel α-globin gene triplicates provides more insight for the research of thalassemia variants and indicates that TGS has significant advantages on genetic testing of thalassemia for the reliability, accuracy and comprehensiveness.

Causal links of α-thalassemia indices and cardiometabolic traits and diabetes: MR study

Our study aimed to investigate if genetic variants around 16p13.3's HBA1 locus, associated with erythrocyte indices and HbA1c levels, predict α-thalassemia-related erythrocyte indices, cardiometabolic traits, and diabetes risk in Taiwanese individuals. We analyzed Taiwan Biobank data, including whole-genome sequencing from 1,493 participants and genotyping arrays from 129,542 individuals. First, we performed regional association analysis using whole-genome sequencing data to identify genetic variants significantly associated with erythrocyte indices, confirming their linkage disequilibrium with the α0 thalassemia --SEA deletion mutation, a common cause of α-thalassemia in Southeast Asian populations. Deletion mutation sequencing further validated these variants' association with α-thalassemia. Subsequently, we analyzed genotyping array data, revealing associations between specific genetic variants and cardiometabolic traits, including lipid profiles, HbA1c levels, bilirubin levels, and diabetes risk. Using Mendelian randomization, we established causal relationships between α-thalassemia-related erythrocyte indices and cardiometabolic traits, elucidating their role in diabetes susceptibility. Our findings highlight genetic variants around the α-globin genes as surrogate markers for common α-thalassemia mutations in Taiwan, emphasizing the causal links between α-thalassemia-related erythrocyte indices, cardiometabolic traits, and heightened diabetes risk.

Random forest classifiers trained on simulated data enable accurate short read-based genotyping of structural variants in the alpha globin region at Chr16p13.3

In regions where reads don't align well to a reference, it is generally difficult to characterize structural variation using short read sequencing. Here, we utilize machine learning classifiers and short sequence reads to genotype structural variants in the alpha globin locus on chromosome 16, a medically-relevant region that is challenging to genotype in individuals. Using models trained only with simulated data, we accurately genotype two hard-to-distinguish deletions in two separate human cohorts. Furthermore, population allele frequencies produced by our methods across a wide set of ancestries agree more closely with previously-determined frequencies than those obtained using currently available genotyping software.

The Spectrum of α-Thalassemia Mutations in Syrian Patients

α-Thalassemia (α-thal) is a globally prevalent genetic disorder of hemoglobin (Hb) structure where the rate of α-globin chain synthesis is reduced or absent due to the presence of α-globin mutation(s). The aim of this study is to define the spectrum of α-globin gene mutations and evaluate their allele frequency in a group of α-thal carriers. A total of 55 individuals with possible α-thal patients were referred from the thalassemia centers in Syria. They have unexplained hypochromia and microcytosis. All patients were genetically tested for 21 common α-globin gene mutations using reverse hybridization kit. Seven different α-globin gene mutations and 13 different genotypes were detected in 55 patients. The two most frequently encountered mutations were -α3.7 deletion (47.1%) and --MED mutation (21.4%). The most commonly observed genotype was -α3.7/αα (40%), followed by --MED/αα genotype (21.8%). We determined the most common α thalassemia mutations in the Syrian patients. α-Thalassemia mutations with deletions were mostly observed in our study.

Development of a Quantitative Multiplex PCR to Detect Three Common Alpha Thalassemia Deletions

Alpha thalassemia is an autosomal recessive genetic disorder with a high prevalence in the Middle East. The severe form of alpha-thalassemia is incompatible with life and can cause significant obstetric complications in the mother. Therefore, it is important to determine the genotype in parents who have a chance of having a fetus with one of the severe forms of this disease. A total of 112 samples that were previously analyzed for common alpha thalassemia mutations in Iran were used in this study. A new multiplex PCR including quantitative polymerase chain reaction to amplify the homologous regions of the alpha-globin gene cluster and fluorescent gap PCR was designed to identify -α3.7, -α4.2, --MED deletions. The ROC curve was used to determine the optimum cutoff points. Statistical analysis showed that there is a significant difference between the peak height ratios for different genotypes. The peak corresponding to the 297 bp fragment resulting from the amplification of the allele with MED-I deletion was detected in all the samples with this deletion. Different cutoffs for a range of sensitivities and specificities were determined by the ROC curve. The suggested method can identify three common large deletions in the alpha-globin gene cluster. A study with a larger sample size can provide more accurate information about the sensitivity and specificity of this test.

Ancient genomic linkage couples metabolism with erythroid development

Generation of mature cells from progenitors requires tight coupling of differentiation and metabolism. During erythropoiesis, erythroblasts are required to massively upregulate globin synthesis then clear extraneous material and enucleate to produce erythrocytes1-3. Nprl3 has remained in synteny with the α-globin genes for >500 million years4, and harbours the majority of the α-globin enhancers5. Nprl3 is a highly conserved inhibitor of mTORC1, which controls cellular metabolism. However, whether Nprl3 itself serves an erythroid role is unknown. Here, we show that Nprl3 is a key regulator of erythroid metabolism. Using Nprl3-deficient fetal liver and adult competitive bone marrow - fetal liver chimeras, we show that NprI3 is required for sufficient erythropoiesis. Loss of Nprl3 elevates mTORC1 signalling, suppresses autophagy and disrupts erythroblast glycolysis and redox control. Human CD34+ progenitors lacking NPRL3 produce fewer enucleated cells and demonstrate dysregulated mTORC1 signalling in response to nutrient availability and erythropoietin. Finally, we show that the α-globin enhancers upregulate NprI3 expression, and that this activity is necessary for optimal erythropoiesis. Therefore, the anciently conserved linkage of NprI3, α-globin and their associated enhancers has enabled coupling of metabolic and developmental control in erythroid cells. This may enable erythropoiesis to adapt to fluctuating nutritional and environmental conditions.

Prevalence Rate of Thalassemia Carriers among Individuals with Microcytosis or Hypochromia in Portugal

INTRODUCTION

Microcytosis and hypochromia result from deficient hemoglobin synthesis in red blood cells and are easily detected in a complete blood count test. These conditions are mainly due to iron nutritional deficiency, but may also result from some genetic diseases, such as thalassemia. The aim of this study was to determine the contribution of β- and α-thalassemia to these abnormal hematological phenotypes in a representative sample of adult individuals living in Portugal who participated in the first Portuguese National Health Examination Survey (INSEF).

MATERIAL AND METHODS

Among the 4808 INSEF participants, 204 had microcytosis, hypochromia or both. The corresponding 204 DNAs were screened for changes in the β-globin gene by next-generation sequencing and Sanger sequencing. In addition, α-thalassemia deletions within the α-globin cluster were investigated by Gap-PCR and multiplex ligation-dependent probe amplification.

RESULTS

In this selected subgroup of INSEF participants, 54 had α-thalassemia (26%), predominantly caused by the -α3.7kb deletion, and 22 were β-thalassemia carriers (11%) mainly due to point mutations in the β-globin gene previously known in Portugal.

CONCLUSION

Thalassemia trait is a frequent cause of microcytosis or hypochromia in Portugal since this genetic condition was found in 37% of the investigated cases.

Differences in the distribution of hemoglobin variants according to the geographic regions in a Colombian population

INTRODUCTION

Colombia has been subject to intense genetic and cultural currents due to its geographical location. Hemoglobinopathies are the most common recessive diseases found worldwide and represent an important public health problem, according to the region and ancestry of each country.

OBJECTIVES

To evaluate the frequency of hemoglobin variants according to the geographical region in a population group adjusted to sex and age in Colombia.

METHODS

This was a descriptive retrospective study of hemoglobin variants performed by electrophoresis in patients treated at and/or referred to specialized care institutions in Bogota, Colombia between January 2009 and December 2020.

RESULTS

A total of 2,224 results were analyzed, 48.4% male and 51.5% female; 63.3% of patients were without alterations, 14.3% presented with thalassemia, 17.3%, HbS, 2.3%, HbS/C, 1.8%, HbC, 0.5%, HbE and 0.5% persistent HbF, with HbS being more prevalent in males (p = 0.005). When assessing the geographical regions of Colombia, a higher prevalence of HbS was found in the Pacific (p = 0.005) and Caribbean regions, while Thalassemia and HbS were more prevalent in the Andean and Orinoquia regions, and it was rare to find any hemoglobinopathies (p = 0.0001) in the Amazonian region.

CONCLUSIONS

The main hemoglobinopathies found in Colombia are HbS, predominantly in males, and Thalassemia. The distribution of hemoglobinopathies in different geographical regions of Colombia is influenced by ancestry.

Revisiting and updating molecular epidemiology of α-thalassemia mutations in Thailand using MLPA and new multiplex gap-PCR for nine α-thalassemia deletion

α-thalassemia is an inherited blood disorder that is most frequently found in Southeast Asian populations. In Thailand, molecular characterization can diagnose most patients with α-thalassemia; however, several atypical patients are also observed in routine analyses. Here, we characterized α-thalassemia mutations among 137 Hemoglobin H (Hb H) disease patients and three fetuses of Hb Bart's hydrops, a fatal clinical phenotype of α-thalassemia. Specifically, we performed multiplex ligation-dependent probe amplification (MLPA) followed by direct DNA sequencing. We noticed common genotypes in 129 patients and eight patients had rare Hb H disease caused by compound heterozygous α0-thalassemia (--CR or --SA deletion) with α+-thalassemia (-α3.7/-α4.2/αConstant Springα). Furthermore, two affected fetuses had the --SA/--SEA and one had the --CR/--SEA genotypes. Next, we developed and validated a new multiplex gap-PCR and applied this method to 844 subjects with microcytic red blood cells (RBCs) from various parts of Thailand. The frequency of heterozygous α0-thalassemia was dominated by --SEA 363/844 (43%), followed by --THAI 3/844 (0.4%), --SA 2/844 (0.2%), and --CR 2/844 (0.2%) mutations. These findings suggest that aforementioned four mutations should be routinely applied to increase the effectiveness of diagnosis and genetic counseling in this region.

Functional analysis of three new alpha-thalassemia deletions involving MCS-R2 reveals the presence of an additional enhancer element in the 5' boundary region

We report three novel deletions involving the Multispecies Conserved Sequences (MCS) R2, also known as the Major Regulative Element (MRE), in patients showing the α-thalassemia phenotype. The three new rearrangements showed peculiar positions of the breakpoints. 1) The (αα)ES is a telomeric 110 kb deletion ending inside the MCS-R3 element. 2) The (αα)FG, 984 bp-long, ends 51 bp upstream to MCS-R2; both are associated with a severe α-thalassemia phenotype. 3) The (αα)CT, 5058 bp-long starts at position +93 of MCS-R2 and is the only one associated to a mild α-thalassemia phenotype. To understand the specific role of different segments of the MCS-R2 element and of its boundary regions we carried out transcriptional and expression analysis. Transcriptional analysis of patients' reticulocytes showed that (αα)ES was unable to produce α2-globin mRNA, while a high level of expression of the α2-globin genes (56%) was detected in (αα)CT deletion, characterized by the presence of the first 93 bp of MCS-R2. Expression analysis of constructs containing breakpoints and boundary regions of the deletions (αα)CT and (αα)FG, showed comparable activity both for MCS-R2 and the boundary region (-682/-8). Considering that the (αα)CT deletion, almost entirely removing MCS-R2, has a less severe phenotype than the (αα)FG α0thalassemia deletion, removing both MCS-R2 almost entirely and an upstream 679 bp, we infer for the first time that an enhancer element must exist in this region that helps to increase the expression of the α-globin genes. The genotype-phenotype relationship of other previously published MCS-R2 deletions strengthened our hypothesis.

Additional value of red blood cell parameters in predicting uncommon α-thalassemia; experience from 10 years of α-globin gene sequencing and copy number variation analysis

INTRODUCTION

The diagnosis of rare forms of α-thalassemia requires laborious genetic analyses. Accurate sample selection for such evaluation is therefore essential. The main objectives of this study were to investigate the predictive power of red blood cell parameters to detect rare forms of α-thalassemia (substudy 1), and to explore the frequency of rare versus common forms of α-thalassemia in our sample population (substudy 2).

METHODS

In substudy 1, we reviewed all blood samples selected for extended α-hemoglobinopathy evaluation at our laboratory during 2011-2020 (n = 1217), which included DNA sequencing and/or copy number variation analysis. We assessed α-thalassemia positive samples at different levels of mean corpuscular hemoglobin (MCH) alone and in combination with results for red blood cell count (RBC) or red cell distribution width (RDW). In substudy 2, we examined the distribution of α-thalassemia genotypes for all samples submitted to a first-tier hemoglobinopathy evaluation at our laboratory during 2014-2020 (n = 6495).

RESULTS

In substudy 1, both RBC and RDW added predictive value in detecting rare forms of α-thalassemia in samples from adults and children. In adult samples with MCH ≤ 23 pg, the presence of erythrocytosis increased the detection rate from 27% to 74% as compared to non-erythrocytosis, while normal RDW increased the detection rate from 36% to 86% as compared to elevated RDW. In substudy 2, rare forms of α-thalassemia were detected in 12% of α-thalassemia positive samples.

CONCLUSION

Initial assessment of MCH, RBC, and RDW provided valuable predictive information about the presence of rare forms of α-thalassemia during hemoglobinopathy evaluation.

The Clinical Phenotypes of Alpha Thalassemia

Clinical manifestations of α-thalassemia range from no symptoms to severe transfusion-dependent anemia. Alpha thalassemia trait is deletion of 1 to 2 α-globin genes, whereas α-thalassemia major (ATM; Barts hydrops fetalis) is the deletion all 4 α genes. All other genotypes of intermediate severity are categorized as HbH disease, a vastly heterogenous group. Clinical spectrum is classified as mild, moderate, and severe by symptoms and need for intervention. Anemia in prenatal period may be fatal without intrauterine transfusions. New therapies to modify HbH disease or provide cure for ATM are under development.

Diagnostik und Therapie der alpha- und beta-Thalassämien

Die komplexe Behandlung von Patienten mit Thalassämien stellt nicht nur eine medizinische, sondern angesichts der in den letzten Jahren deutlich gestiegenen Patientenzahlen auch eine gesellschaftliche Herausforderung dar, die eine sehr enge Zusammenarbeit aller Behandler erfordert. Der vorliegende Beitrag erläutert Ursachen und Pathogenese der alpha- und beta-Thalassämien und bietet eine Übersicht zu Klinik und Therapien.

Alpha-Thalassemia in Southern Italy: Characterization of Five New Deletions Removing the Alpha-Globin Gene Cluster

α-thalassemia is characterized in about 80% of cases by deletions generated by the presence of duplications and interspersed repeated sequences in the α-globin gene cluster. In a project on the molecular basis of α-thalassemia in Southern Italy, we identified six families, showing an absence of the most common deletions, and normal α-globin gene sequences. Multiplex Ligation-dependent Probe Amplification (MLPA), qRT-PCR, and the sequencing of long-range PCR amplicon have been used for the identification and characterization of new deletions. MLPA analysis for the identification of α- and β-globin rearrangement revealed the presence of five new α-thalassemia deletions. The set-up of qRT-PCR allowed us to delimit the extent of the deletions ranging from about 10 kb to more than 250 kb, two of them being of the telomeric type. The long-range PCR generated a specific anomalous fragment in three deletions, and only several unspecific bands in the other two deletions. The sequencing of the anomalous amplicons revealed the breakpoints of two deletions: the --PA, 34 kb long, identified in two families, and the telomeric --AG, 274 kb long. The anomalous fragment containing the breakpoint of the deletion --FG was partially sequenced, and it was not possible to identify the breakpoints due to the presence of several repetitive Alu sequences. The analysis of the breakpoint regions of the --Sciacca and --Puglia, respectively, are about 10 and 165 kb long, and revealed the presence of repeats that most likely impaired the amplification of a specific fragment for the identification of the breakpoint. MLPA, in association with qRT-PCR and long-range PCR, is a good approach for the identification and molecular characterization of rare or new deletions. Breakpoint analysis confirms that Alu sequences play an important role in favoring unequal crossing-over. Southern Italy shows considerable genetic heterogeneity, as expected with its central position in the Mediterranean basin, favoring migratory flows.

Development of molecular diagnostic platform for α0 -thalassemia 44.6 kb (Chiang Rai, --CR ) deletion in individuals with microcytic red blood cells across Thailand

INTRODUCTION

The α⁰ -thalassemia 44.6 kb or Chiang Rai (--^CR ) deletion has been reported in northern Thailand and is capable of causing hemoglobin (Hb) H disease and a lethal α-thalassemia genotype, Hb Bart's hydrops fetalis, in this region. However, there are no current data regarding the frequency of --^CR nationwide due to a lack of effective diagnostic assay. Therefore, this study aimed to develop a reliable platform for simultaneous genotyping of --^CR and two common α⁰ -thalassemias in Thailand (--^SEA and --^THAI ) and investigate the frequency of --^CR across Thailand.

METHODS

Multiplex gap-PCR assay and five renewable plasmid DNA controls for --^CR , --^SEA , --^THAI , α2-globin (HBA2), and β-actin (ACTB) were newly developed and validated with reference methods. The developed assay was further tested on 1046 unrelated individuals with a reduced mean corpuscular volume (MCV) of less than 75 fl for investigating genotypic and allelic spectrum of --^CR .

RESULTS

Our developed assay showed 100% concordance with reference methods. The results were valid and reproducible throughout hundreds of reactions. Comparison of the genotypic and allelic spectra revealed that heterozygous --^SEA (--^SEA /αα) and --^SEA alleles were dominant with the frequency of 22.85% (239/1046) and 13.34% (279/2092), respectively. Of these, --^THAI and --^CR were relatively rare in this population and comparable to each other with the allelic frequency of 0.14% (3/2092).

CONCLUSION

This study successfully established a reliable molecular diagnostic platform for genotyping of --^CR , --^SEA , and --^THAI in a single reaction. Additionally, we demonstrated the frequency of --^CR in Thailand for the first time and provided knowledge basis for the planning of severe α-thalassemia prevention and control programs in Thailand, where thalassemia is endemic.

Case report: Long-read sequencing identified a novel 14.9-kb deletion of the α-globin gene locus in a family with α-thalassemia in China

Background: Thalassemia is a hereditary blood disease resulting from globin chain synthesis impairment because of α- and/or β-globin gene variants. α-thalassemia is characterized by non-deletional and deletional variants in the HBA gene locus, of which rare deletional variants are difficult to detect by conventional polymerase chain reaction (PCR)-based methods. Case report: We report the case of a one-month-old boy, who and his mother had abnormal hematological parameters, while his father had normal hematology. Conventional PCR-reverse dot blot (RDB) was performed for all family members to analyze the 23 most common thalassemia variants in China, but did not identify any pathologic variants. Single-molecule real-time (SMRT) long-read sequencing (LRS) technology was then performed and identified an unreported 14.9-kb large deletion (hg38 chr16:168,803-183,737) of the α-globin gene locus, which disrupted both HBA1 and HBA2 genes in the proband and his mother. The exact breakpoints of the deletion were confirmed by gap-PCR and Sanger sequencing. Conclusion: We have detected a novel large deletion in α-globin gene locus in China, which not only enriches the variant spectrum of thalassemia, but also demonstrates the accuracy and efficiency of LRS in detecting rare and novel deletions.

Pregnancy outcomes among women affected with thalassemia traits

OBJECTIVE

To compare the maternal and perinatal outcomes between a group of pregnant women diagnosed with thalassemia traits and normal controls.

STUDY DESIGN

A retrospective cohort study was conducted on singleton pregnant women affected and unaffected by thalassemia traits who attended an antenatal care clinic and delivered in Siriraj Hospital. Thalassemia status for all subjects was diagnosed by hemoglobin typing and/or DNA analysis. Patient charts were reviewed from January 2007 to December 2018. The control participants were randomly selected from the same period, with a control-case ratio of around 1:1.

RESULTS

Overall, 1288 women with thalassemia traits (348 with α thal-1 trait, 424 with β thal trait and 516 with HbE trait) and 1305 women in the control group were recruited. Baseline characteristics of both groups were similar, with the exception that the hematocrit level in the first trimester in the thalassemia trait group was significantly lower than that in the control group (34.8 ± 3.4% VS 36.9 ± 3.0%; p < 0.001). The prevalence of pregnancy-induced hypertension (PIH) was higher in the thalassemia trait group, at 6.9% VS 4.7% in the control group; p = 0.018. When subgroups were analyzed between each thalassemia trait, the number of maternal anemias in the first and third trimester was higher for all thalassemia traits compared to the normal group. The β thal and HbE traits increased the risk of PIH, with a relative risk (RR) = 1.67 and 1.66, respectively.

CONCLUSIONS

Thalassemia traits minimally but significantly increase the risk of hypertensive disorders and maternal anemia. In addition, physiological changes during pregnancy may worsen the severity of anemia in the pregnant women with thalassemia traits.

Genotypic spectrum of α-thalassemia and β-thalassemia in newborns of the Li minority in Hainan province, China

Purpose

To explore the genotypes and allele frequencies of α, β and α+β thalassemias in Li minorities, which resided in Hainan Province of China for a long time.

Methods

In the present study, 1,438 newborns of the Li minority were collected from January 2020 to April 2021. The genotypes of thalassemia were detected by fluorescence PCR and verified by flow-through hybridization PCR analyses. Rare genotypes were detected by restriction fragment length polymorphism electrophoresis and Sanger DNA sequencing.

Results

Among 1,438 participants, 1,024 (71.2%) were diagnosed with any kind of thalassemia. Among all thalassemia carriers, 902 (88.09%) subjects were diagnosed with α-thalassemia, and 18 subtypes of α-thalassemia were detected, with the top three genotypes being -α^4.2/αα (25.39%), -α^3.7/αα (22.62%) and α^WSα/αα (16.96%). Thirty-two (3.13%) patients were β-thalassemia carriers, and 6 types of β-thalassemia genotypes were detected. The top two genotypes were β^CD41-42/β^N (46.88%) and β^-28/β^N (18.75%). Additionally, 90 (8.79%) cases were α + β-thalassemia, and the top two genotypes were -α^3.7/αα, β^CD41-42/β^N (30.00%) and -α^4.2/αα, β^CD41-42/β^N (26.67%). Furthermore, two genotypes (-α^4.2/HKαα and β^{CD76 GCT > CCT}/β^N) were first identified in Hainan Province_, and β^{CD76 GCT > CCT}/β^N was first identified in China.

Conclusion

Newborns of Li have a higher prevalence of thalassemia for a long period, and further education on the impact of thalassemia, follow-up studies of the clinical manifestation and treatment and proper intervention methods should be designed to reduce the burden of thalassemia and enhance the quality of life in Li newborns.

An analysis of the distribution and spectrum of alpha thalassemia mutations in Rasht City, North of Iran

Background

Alpha thalassemia is one of the most common hereditary hemoglobin disorders worldwide, particularly in the Middle East, including Iran. Therefore, determining the spectrum and distribution of alpha thalassemia mutation is a fundamental component of preventive approaches and management strategies.

Methods

The present study reviews the genetic testing and blood laboratory results of 455 candidates eligible for marriage who were suspected of being thalassemia carriers and on whom genetic testing was performed from 21 March 2013 to 31 December 2020 in Rasht City.

Results

A total of 114 (25.05%) alpha thalassemia cases were identified. Fifteen different alpha mutations were found. The most common mutation among the study population was -α^3.7 deletion in 55 patients (48.24%), followed by Hb Constant Spring (C.S) in 21 patients (18.42%) and poly A2 in 16 (14.03%). Also, most of the patients were silent carriers. The deletion type of mutation was much more common than non-deletion mutations.

Conclusion

Our study reveals genetic heterogeneity and alpha thalassemia diversity among the Rasht City population. We expect that these findings will help guide premarital screening and genetic counseling, prenatal diagnosis of thalassemia, preventive strategy development, as well as a compilation of the alpha thalassemia catalog in Guilan province.

Whole genome sequencing identifies structural variants contributing to hematologic traits in the NHLBI TOPMed program

Genome-wide association studies have identified thousands of single nucleotide variants and small indels that contribute to variation in hematologic traits. While structural variants are known to cause rare blood or hematopoietic disorders, the genome-wide contribution of structural variants to quantitative blood cell trait variation is unknown. Here we utilized whole genome sequencing data in ancestrally diverse participants of the NHLBI Trans Omics for Precision Medicine program (N = 50,675) to detect structural variants associated with hematologic traits. Using single variant tests, we assessed the association of common and rare structural variants with red cell-, white cell-, and platelet-related quantitative traits and observed 21 independent signals (12 common and 9 rare) reaching genome-wide significance. The majority of these associations (N = 18) replicated in independent datasets. In genome-editing experiments, we provide evidence that a deletion associated with lower monocyte counts leads to disruption of an S1PR3 monocyte enhancer and decreased S1PR3 expression.

The -α3.7III subtype of α+-thalassemia was identified in China

OBJECTIVE

The 3.7 kb deletion (-α^3.7) in the α-globin cluster, which characterizes α⁺-thalassemia, has been reported to have a carrier rate of 4.78% in southern China. Three -α^3.7 subtypes have been identified worldwide. However, the -α^{3.7 III} subtype has not previously been identified in China. Herein, we reported identification of the -α^{3.7 III} subtype in a Chinese patient.

METHODS

We used gap-PCR and a liquid chip system to detect α-thalassemia mutations. Multiple ligation-dependent probe amplification was performed to detect the large deletion. We finally used Sanger sequencing and single molecule real-time sequencing to characterize and confirm the genotype.

RESULTS

The proband, characterized as -α^{3.7 III} heterozygous, showed microcytosis and hypochromic red cells, with a mean corpuscular volume of 78 fL and mean corpuscular hemoglobin of 25.4 pg. The proband's mutation was inherited from her father, who had normal blood parameters.

CONCLUSION

We first identified the -α^{3.7 III} subtype in China. Consequently, all -α^3.7 subtypes have now been identified in the Chinese population. Therefore, attention should be paid to -α^{3.7 III} in clinical prenatal diagnosis, given that commonly used methods such as gap-PCR may lead to misdiagnosis or missed diagnosis.

Novel Decision Tool for More Severe α-Thalassemia Genotypes Screening with Functional Loss of Two or More α-Globin Genes: A Diagnostic Test Study

After the exclusion of iron deficiency and β-thalassemia, molecular research for α-thalassemia is recommended to investigate microcytic anemia. Aiming to suggest more efficiently the molecular analysis for individuals with a greater chance of having a symptomatic form of the disease, we have developed and validated a new decision tool to predict the presence of two or more deletions of α-thalassemia, increasing considerably the pre-test probability. The model was created using the variables: the percentage of HbA₂, serum ferritin and mean corpuscular volume standardized by age. The model was trained in 134 patients and validated in 160 randomly selected patients from the total sample. We used Youden's index applied to the ROC curve methodology to establish the optimal odds ratio (OR) cut-off for the presence of two or more α-globin gene deletions. Using the OR cut-off of 0.4, the model's negative predictive value (NPV) was 96.8%; the cut-off point accuracy was 85.4%; and the molecular analysis pre-test probability increased from 25.9% to 65.4% after the use of the proposed model. This tool aims to assist the physician in deciding when to perform molecular studies for the diagnosis of α-thalassemia. The model is useful in places with few financial health resources.

Thalassaemia - part 1: a clinical update for the dental team

Thalassaemia is a genetic disorder that affects haemoglobin function. It is an abnormality of haemoglobin caused by mutation of genes related to alpha or beta globin chains that can be further subdivided into categories. These haematological conditions can vary from mild forms, which present as mild anaemia, to severe forms, that can become life-threatening. The window for dental treatment is often limited by several factors involving medical management, such as the need for antibiotic cover or blood transfusions. The lifetime management of the medical conditions are onerous and can place significant physical and psychological burden on the patient. This paper is part of a two-part series on thalassaemia. Part one focuses on the clinical manifestations patients may present with, treatment regimens and dental implications of such presentations. Part two explores the perspectives of thalassaemia patients on their dental experience.

Genetic testing of sperm donors at a human sperm bank in China

Background

In China, numerous human sperm banks only perform three-generation family history evaluation to exclude genetic diseases with clinical symptoms; therefore, many inherited risks cannot be detected before donor qualification even when a thorough genetic family history evaluation has been performed. Hence, the risk of recessive disease inheritance persists with the current eligibility guidelines in China regarding the donor selection process.

Methods

Retrospective study that reviewed the genetic test analyses and clinical outcomes of young adult men who were qualified sperm donors at the Hunan Province Human Sperm Bank of China from January 1, 2018, to May 1, 2021. We included a total of 3231 qualified sperm donors: all donors underwent primary screening for thalassemia and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Whereafter, 278 of donors underwent genetic testing for specific genes, and 43 donors underwent whole exome sequencing.

Results

2.4% of 3231 qualified sperm donors might have thalassemia and 1.4% might have G6PD deficiency. Sperm donors with thalassemia and G6PD deficiency would be eliminated. Specific gene testing identified 7 of the 278 donors (2.5%) as carriers of at least one pathogenic or likely pathogenic variant in a gene, including 1.9% of 154 donors (3/154) as carrier variants in α-Like or β-Like globin genes, 17.6% of 17 donors (3/17) as carrier variants in GJB2, 12.5% of 8 donors (1/8) as carrier variants in SMN1. In addition, among the 43 sperm donors carrying the 111 pathogenic/likely pathogenic variants, eight (18.6%) were carriers of pathogenic variants of the GJB2 gene. The frequency, therefore, was approximately 1 in 5.

Conclusions

The data suggest that used blood routine and RDT can make a preliminary screening of sperm donors, and special gene testing should be performed for sperm donors according to the regional incidence of specific genetic diseases. Meanwhile, whole exome sequencing can be used as a supplementary application in sperm donor genetic testing, and aid a successful and healthy pregnancy. However, industry guidelines must be modified to incorporate its use.

Clinical and genetic characteristics of hemoglobin H disease in Iran

Hemoglobin H (Hb H) disease is a subtype of α-thalassemia caused by deletional and/or non-deletional mutations in three alpha-globin genes in which the various genotypes determine the disease severity. This study was aimed to investigate the frequency of alpha gene mutations and genotypes and their correlation with hematological and clinical characteristics in Iran. Among 202 patients diagnosed with Hb H disease through a national study in Iran according to standard methods, we had access to the hematologic and clinical findings and genetic data of 101 patients in whom genetic study was performed. Genomic DNA from peripheral blood was extracted and analyzed for identification of α-globin gene mutations using Multiplex Gap Polymerase Chain Reaction, Reverse Hybridization Assay, and finally Direct DNA Sequencing method. Twenty-one different mutations and thirty genotypes were detected in 101 patients with Hb H disease. In total, 39 patients (38.6%) were deletional and 62 patients (61.4%) were non-deletional type of the disease. The _--^MED mutation was highly prevalent in almost half of the patients (56.4%). Among various genotypes, -^MED/-a^3.7 (29.7%) and -α^20.5/-α^5NT (6.9%) were the most prevalent genotypes found in the studied group. Patients with non-deletional type presented with more severe hematological and clinical findings. Hb H percentage and serum ferritin levels were significantly higher in non-deletional patients in comparison to the deletional group (p < 0.05). 12 (11.9%) and 40 (39.6%) out of 101 patients were on regular and occasional transfusions, respectively. 83% of those with regular transfusion belonged to the non-deletional group. Among transfusion-dependent patients, -^MED/α^CSα and α^20.5/-α^5NT were the most common genotypes. In this study, two patients with -α^20.5/α^CSα and -^MED/α^-5NT genotypes experienced thrombotic events. This study indicated that although non-deletional genotypes of Hb H disease were responsible for more clinical severity of the disease, due to the presence of severe phenotypes even in deletional types, no definite correlation was found between genotype and phenotype.

The need to perform α‐thalassemia genetic testing in Italian patients with β‐thalassemia trait: A case report

Here, we describe a case report of a Sardinian woman diagnosed as pure beta‐thalassemia carrier for her anemia who underwent to alpha‐thalassemia genetic testing that revealed she was heterozygous for both thalssemias. This allowed to reach a conclusive diagnosis useful for family counseling and for assess the reproductive risk.

[Diagnostics and treatment of alpha- and beta-thalassemias]

Thalassemias are a heterogeneous group of genetic diseases based on a quantitative disorder of globin chain synthesis. They are among the most frequent monogenic hereditary diseases worldwide. Migration during recent years led to a profoundly increasing number of patients in countries where the indigenous population has not been affected. The complex treatment of the patients represents a medical and socioeconomic challenge with the need for structured interdisciplinary clinical care and close collaboration among healthcare providers, regulatory authorities, and health care insurance companies. The following article provides an overview of the causes, pathogenesis, clinical presentation, and treatment of alpha- and beta-thalassemias.

Common Single Nucleotide Polymorphism of TMPRSS6, an Iron Regulation Gene, Associated with Variable Red Blood Cell Indices in Deletional α-Globin Genotypes

Red blood cell (RBC) indices, including mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH), have been widely used for primary screening for thalassaemia (thal) syndromes. Recently, a single nucleotide polymorphism (SNP) rs855791 of TMPRSS6, an iron regulation gene involved in the substitution of a nucleotide between thymine (T) and cytosine (C) in exon 17 resulted in an amino acid change, p.Val736Ala (V736A), has been described to associate with RBC indices. The objective was to study the effects of common SNP V736A on RBC indices in deletional α-thal variations. SNP rs855791 genotypes were identified from 433 Thai volunteers, including 32.6% males and 67.4% females with an average age of 23.0 ± 8.7 years. These populations included individuals (82.4%) who had normal globin genotype (αα/αα, ββ) and α-thal carriers, which were divided into two subgroups, including α⁺-thal (-α/αα) (14.1%) and α^o-thal (--/αα) (3.5%). Among three SNP genotypes, the C allele gradually expressed higher MCV and MCH than those of the T allele in both α⁺- and α^o-thal traits. Importantly, SNP rs855791 of TMPRSS6 responded to α-globin deletions for sustaining RBC sizes and haemoglobinisation in α-thal carriers.

Identifying Gingival Pigmentation Patterns and Skin Color and Its Co-relation With Serum Ferritin Levels in Thalassemic Patients

Background: Patients with β-thalassemia major (β-TM), a genetic issue due to hemoglobin (Hb) synthesis disorder, require life-long erythrocyte transfusion. The purpose of this study is to evaluate and compare gingival pigmentation and skin color with serum ferritin levels of patients with β-TM, using the Dummett's oral pigmentation index (DOPI) and Fitzpatrick skin scale, respectively.

Methods: A total of 100 patients were monitored at a thalassemia care center. Each patient's gingival pigmentation and skin color were matched with DOPI and the skin scale under natural light. Serum ferritin levels, the interval of blood transfusions, and iron chelation medications were studied. A gingival pigmentation score and skin color type were compared with the serum ferritin.

Results: A significant correlation was found between age, serum ferritin, pigmentation score, and skin color, which means as serum ferritin level increases, gingival pigmentation score increases, and skin color darkens.

Conclusion: This study evaluated the correlation between gingival pigmentation and skin color with serum ferritin levels and established gingival pigmentation as a sign of iron deposition in β-TM patients. This is the simplest and least invasive method for evaluating serum ferritin level parameters in β-TM patients.

Screening and diagnosis of hemoglobinopathies in Germany: Current state and future perspectives

This monocentric study conducted at the Pediatric and Adult Hemoglobinopathy Outpatient Units of the University Hospital of Essen summarizes the results of hemoglobinopathies diagnosed between August 2018 and September 2021, prior to the introduction of a general newborn screening (NBS) for SCD in Germany (October 2021). In total, 339 patients (pts.), 182 pediatric [50.5% males (92/182)] and 157 adult pts. [75.8% females (119/157)] were diagnosed by molecular analysis. The most common (parental) descent among affected pts. were the Middle Eastern and North African/Turkey (Turkey: 19.8%, Syria: 11.8%, and Iraq: 5.9%), and the sub-Saharan African region (21.3%). Median age at diagnosis in pediatric carriers [N = 157; 54.1% males (85/157)] was 6.2 yrs. (range 1 (months) mos.–17.8 yrs.) and 31 yrs. (range 18–65 yrs.) in adults [N = 53; 75.2% females (115/153)]. Median age at diagnosis of homozygous or compound-heterozygous disease in pediatric pts. (72% (18/25) females) was 3.7 yrs., range 4 mos.–17 yrs. (HbSS (N = 13): 2.5 yrs., range 5 mos.–7.8 yrs.; HbS/C disease (N = 5): 8 yrs., range 1–8 yrs.; homozygous/compound heterozygous β-thalassemia (N = 5): 8 yrs., range 3–13 yrs.), in contrast to HbH disease (N = 5): 18 yrs. (median), range 12–40 yrs. Hemoglobinopathies represent a relevant health problem in Germany due to immigration and late diagnosis of second/third generation migrants. SCD-NBS will accelerate diagnosis and might result in reduction of disease-associated morbidity. However, diagnosis of carriers and/or disease-states (i.e. thalassemic syndromes) in newly immigrated and undiagnosed patients will further be delayed. A first major step has been taken, but further steps are required.

Loop-mediated isothermal amplification (LAMP) colorimetric phenol red assay for rapid identification of α0-thalassemia: Application to population screening and prenatal diagnosis

Background

Identification of α⁰-thalassemia (SEA and THAI deletions) is essential in preventing and controlling of severe thalassemia diseases. We have developed the LAMP colorimetric assays for the detection of these two thalassemia defects and validated them in population screening and prenatal diagnosis.

Methods

Three LAMP colorimetric assays specific for α⁰-thalassemia (SEA deletion), α⁰-thalassemia (THAI deletion) and normal DNA sequence were developed. These assays were validated on 341 subjects who had initial thalassemia screening positive and various thalassemia genotypes. Prenatal diagnosis of α⁰-thalassemia (SEA deletion) was done on 33 fetuses at risk of having Hb Bart’s hydrops fetalis syndrome.

Results

The LAMP colorimetric assays for α⁰-thalassemia (SEA and THAI deletions) could be clearly interpreted by naked eyes. The assay for α⁰-thalassemia (SEA deletion) showed a 100% (62/62 x 100) sensitivity and 98.2% (274/279 x 100) specificity whereas, that of the α⁰-thalassemia (THAI deletion) showed 100% (1/1 x 100) sensitivity and 99.7% (339/340 x 100) specificity. We obtained a 100% concordant prenatal diagnosis results using LAMP assays of α⁰-thalassemia (SEA deletion) in 33 fetuses as compared to the conventional PCR analysis.

Conclusions

The LAMP colorimetric assays developed are simple, rapid, and do not require sophisticated equipment. Inclusion of the LAMP tests in the existing screening protocol significantly reduce the screening cost and the molecular analysis workload, which should prove useful in the prevention and control program of hemoglobinopathies in the region.

Diagnosis of α0-thalassemia Chiang Rai (--CR) deletion by melt curve analysis in Northern Thailand

A large novel 44.6 kb deletion named α⁰-thalassemia Chiang Rai (--^CR) was first described in the individuals with uncommon Hb Bart's hydrops fetalis and HbH disease. This study aimed to develop a real-time gap PCR and melt curve analysis for the detection of --^CR and investigate its frequency in northern Thailand. Among 4,952 blood samples, the assay was performed in 525 samples with a mean corpuscular volume (MCV) < 80 fL, HbA₂ < 3.5%, HbA₂+E < 25%, and negative for common deletional α⁰-thalassemia --^SEA and --^THAI. The developed method showed T_m values of 85.8 ± 0.0 °C and 91.5 ± 0.1 °C, which were specific for --^CR and wild-type alleles, respectively. Nine (0.18% of 4,952 or 1.71% of 525) were positive for --^CR, in which two were HbH disease and the rest were heterozygous for --^CR. This study demonstrated the success of real-time gap PCR with melt curve analysis for --^CR diagnosis. Additionally, the prevalence of --^CR in the northern Thai population was comparable to --^THAI. Thus, this study implies the importance of --^CR in northern Thailand. Moreover, the developed real-time gap PCR with melt curve analysis is simple and highly accurate, and may be considered as an additional tool for routine α⁰-thalassemia --^CR diagnosis in this region.