Heterogeneity of hemoglobin H disease in childhood

Evaluated NSUN3 in reticulocytes from HbH-CS disease that reflects cellular stress in erythroblasts

Hemoglobin H Disease-Constant Spring (HbH-CS) represents a severe variant of α-thalassemia characterized by a fundamental pathological mechanism involving inadequate synthesis of α-globin chains. This deficiency results in the formation of unstable Hemoglobin H (HbH) due to the aggregation of free β-globin chains, which subsequently induces an imbalance in oxidative stress within erythrocytes. This imbalance leads to an abnormal accumulation of reactive oxygen species (ROS), which in turn promotes lipid peroxidation, culminating in the production of malondialdehyde (MDA) and a significant depletion of glutathione (GSH). Concurrently, Nrf2 is translocated to the nucleus, where it activates the antioxidant response element (ARE) to mitigate cellular stress. Here, we report that NSUN3 (which, together with ALKBH1, maintains mitochondrial function through m5C→f5C modification) is abnormally overexpressed in reticulocytes from patients with HbH-CS, and an in vitro cellular model of NSUN3 overexpression/silencing was constructed using K562 cells, which have the potential for erythroid lineage differentiation and retain an intact cluster of bead protein genes. Functional assays indicated that the overexpression of NSUN3 significantly intensified the accumulation of intracellular ROS and MDA, led to a reduction in GSH levels, and diminished the overall cellular antioxidant capacity (T-AOC). This may be due to ROS accumulation resulting from inhibition of mitochondrial respiratory chain complex I, II, and IV synthesis through aberrant m5C→f5C modification. In addition, NSUN3 overexpression further exacerbates oxidative stress by inhibiting the phosphorylation of Nrf2 hindering its translocation into the nucleus and weakening the cellular antioxidant system. Moreover, we also observed that NSUN3 overexpression exacerbated intracellular DNA damage and inhibited cellular value-added activity, and silencing NSUN3 showed the opposite result. Our research offers initial insights into the molecular mechanisms through which NSUN3 modulates oxidative stress in erythrocytes via its role in epigenetic modifications. These findings contribute to a deeper understanding of the clinical management of patients with Hb H-CS.

Impact of HbE mutation on the clinical severity of HbH disease: A multicentre study from Thailand

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.

Efficient and in situ correction of hemoglobin Constant Spring mutation by prime editing in human hematopoietic cells

Hemoglobin Constant Spring (Hb CS) is the most common non-deletional and clinically significant α-thalassemic mutation, and it is caused by an anti-termination mutation at the α2-globin gene stop codon. We developed a prime editing strategy for the creation and correction of Hb CS. We showed that prime editing could efficiently introduce Hb CS mutations in both human erythroblast cell lines (an average frequency of 32%) and primary hematopoietic stem and progenitor cells (HSPCs) from healthy donors (an average frequency of 27%). By targeting the established Hb CS homozygous erythroblasts, we achieved an average frequency of 32% in situ correction without selection. Notably, prime editing corrected the Hb CS mutation to wild type at an average frequency of 21% in HSPCs from three patients with hemoglobin H Constant Spring (HCS). Erythrocytes that differentiated from prime-edited erythroblasts or HSPCs exhibited a significant reduction in the amount of αCS-globin chains. Insertions and deletions on HBA2 locus and Cas9-dependent DNA off-target editing were detected with relatively low frequency after prime editing. Our findings showed that prime editing can successfully correct Hb CS in erythroblasts and patient HSPCs, which provides proof of principle for its therapeutic potential in HCS.

Disease burden, management strategies, and unmet needs in α-thalassemia due to hemoglobin H disease

Alpha-thalassemia is an inherited blood disorder caused by impaired α-globin chain production, leading to anemia and other complications. Hemoglobin H (HbH) disease is caused by a combination of mutations generally affecting the expression of three of four α-globin alleles; disease severity is highly heterogeneous, largely driven by genotype. Notably, non-deletional mutations cause a greater degree of ineffective erythropoiesis and hemolysis, higher transfusion burden, and increased complication risks versus deletional mutations. There are limited treatment options for HbH disease, and effective therapies are needed. This review discusses the pathophysiology of HbH disease, current management strategies, unmet needs, and emerging treatment options.

De-novo ATR-16 syndrome associated with inherited hemoglobin Evanston causing HbH phenotype: a rare occurrence

Abnormality of three α-globin genes, either deletion or point mutation results in symptomatic Hemoglobin H (HbH) phenotype. Most of such cases of α-globin defects are inherited from the parents, de-novo cases are exceedingly rare. Herein, a case of HbH is reported where the proband inherited one α-globin gene with a point mutation (αEvanston) from the mother. This was associated with large de-novo deletion of chromosome 16p13.3 resulting in α-thalassemia and mental retardation (ATR-16) syndrome. This deletion also encompassed two α-globin genes from chromosome 16, eventually leading to --/ααEvanston genotype, explaining the clinical presentation of the proband. The challenges in screening of such cases and confirming the molecular diagnosis along with the mode of inheritance has been discussed.

Hemoglobin Balkh, a Novel Mutation in Codon 132 of α2-Globin Gene [α132(H15) (+T) or HBA2:C.396dup (p.Val134fs)]: A Case Report and Insight into the Pathophysiology

We report a novel mutation on α2-globin gene leading to an elongated α-chain. This novel frameshift mutation was detected in a 13-year-old boy from Balkh province, Afghanistan. DNA analysis identified an insertion of thymine (T) at codon 132 [HBA2:c.396dup (p.Val134fs)]. We named the novel hemoglobin variant 'Hemoglobin Balkh' after the geographic location from which the patient originated. This novel variant was found in association with α3.7 kb α-globin gene deletion, suggesting a compound heterozygous state that contributes to the patient's clinical presentation.

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.

Systematic review and evidence gap assessment of the clinical, quality of life, and economic burden of alpha-thalassemia

A recent evidence gaps assessment of the clinical, health-related quality of life, and economic burden associated with α-thalassemia is lacking. We conducted a systematic literature review (SLR) following the methodological and reporting requirements of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Cochrane Handbook for Systematic Reviews, using available literature over the past decade. This SLR identified a considerable evidence gap with regard to understanding the current burden of α-thalassemia as evident from paucity of studies published in the past 10 years. The limited data available still indicate that patients with α-thalassemia experience substantial morbidity and quality of life/economic burden that is generally comparable to patients with β-thalassemia.

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.

Inherited disorders of hemoglobin: A review of old and new diagnostic methods

The genetic regulation of hemoglobin is complex and there are a number of genetic abnormalities that result in clinically important hemoglobin disorders. Here, we review the molecular pathophysiology of hemoglobin disorders and review both old and new methods of diagnosing these disorders. Timely diagnosis of hemoglobinopathies in infants is essential to coordinate optimal life-saving interventions, and accurate identification of carriers of deleterious mutations allows for genetic counseling and informed family planning. The initial laboratory workup of inherited disorders of hemoglobin should include a complete blood count (CBC) and peripheral blood smear, followed by carefully selected tests based on clinical suspicion and available methodology. We discuss the utility and limitations of the various methodologies to fractionate hemoglobin, including cellulose acetate and citrate agar hemoglobin electrophoresis, isoelectric focusing, high-resolution high-performance liquid chromatography, and capillary zone electrophoresis. Recognizing that most of the global burden of hemoglobin disorders exists in low- and middle-income countries, we review the increasingly available array of point-of-care-tests (POCT), which have an increasingly important role in expanding early diagnosis programs to address the global burden of sickle cell disease, including Sickle SCAN, HemoTypeSC, Gazelle Hb Variant, and Smart LifeLC. A comprehensive understanding of the molecular pathophysiology of hemoglobin and the globin genes, as well as a clear understanding of the utility and limitations of currently available diagnostic tests, is essential in reducing global disease burden.

Detecting rare thalassemia in children with anemia using third-generation sequencing

BACKGROUND

In China, conventional genetic testing methods can only detect common thalassemia variants. Accurate detection of rare thalassemia is crucial for clinical diagnosis, especially for children that need long-term blood transfusion. This study aims to explore the application value of third-generation sequencing (TGS) in the diagnosis of rare thalassemia in children with anemia.

METHODS

We enrolled 20 children with anemia, excluding from iron deficiency anemia (IDA). TGS was employed to identify both known and novel thalassemia genotypes, while sanger sequencing was used to confirm the novel mutation detected.

RESULTS

Among the 20 samples, we identified 5 cases of rare thalassemia. These included β-4.9 (hg38,Chr11:5226187-5231089) at HBB gene, α-91(HBA2:c.*91delT), αCD30(HBA2:c.91-93delGAG), Chinese Gγ+(Aγδβ)0(NG_000007.3: g .48795-127698 del 78904) and delta - 77(T > C)(HBD:c.-127T>C). Notably, the -SEA/α-91α genotype associated with severe non-deletional hemoglobin H disease (HbH disease) has not been previously reported. Patients with genotypes β654/β-4.9 and -SEA/α-91α necessitate long-term blood transfusions, and those with the -SEA/αCD30α, Chinese Gγ+(Aγδβ)0 and delta thalassemia demonstrate mild anemia.

CONCLUSIONS

TGS demonstrates promising potential as a diagnostic tool for suspected cases of rare thalassemia in children, especially those suspected to have transfusion-dependent thalassemia (TDT).

Hemoglobin H Disease and Growth: A Comparative Study of DHbH and NDHbH Patients

Background

Hemoglobin H disease (HbH), a hemoglobinopathy resulting from abnormal alpha globin genes, is classified into two categories: deletional HbH (DHbH) and non-deletional HbH (NDHbH). The alpha-mutation genotypes exhibit a range of clinical anemias, which differentially impact patient growth.

Objectives

This retrospective study assessed the growth of HbH patients at Siriraj Hospital, Mahidol University.

Methods

Patients diagnosed with HbH between January 2005 and April 2021 were analyzed using growth standard scores of the Thai Society for Pediatric Endocrinology (2022 version) and BMI-for-age Z scores of the World Health Organization. Growth failure was defined as a patient's height for age exceeding two standard deviations below the mean.

Results

Of the 145 HbH patients, 75 (51.7%) had NDHbH, with --SEA/αCSα being the most common genotype (70 patients; 93.3%). The mean baseline hemoglobin level was significantly lower in NDHbH patients than in DHbH patients (8.16 ± 0.93 g/dL vs. 9.51 ± 0.68 g/dL; P < 0.001). Splenomegaly and growth failure prevalences were higher in NDHbH patients (37.3% vs. 0%, with P < 0.001, and 22.7% vs. 8.6%, with P = 0.020, respectively). Multivariable analysis revealed splenomegaly > 3 cm was associated with growth failure (OR = 4.28; 95% CI, 1.19-15.39; P = 0.026).

Conclusions

NDHbH patients exhibited lower hemoglobin levels and more pronounced splenomegaly than DHbH patients. Growth failure can occur in both HbH types but appears more prevalent in NDHbH. Close monitoring of growth velocity is essential, and early treatment interventions may be required to prevent growth failure.

A novel gain-of-function PIP4K2A mutation elevates the expression of β-globin and aggravates the severity of α-thalassemia

Haemoglobin H (Hb H) disease (intermediate status of α-thalassemia) shows marked phenotypic variability from asymptomatic to severe anaemia. Apart from the combined β-thalassemia allele ameliorating clinical severity, reports of genetic modifier genes affecting the phenotype of Hb H disease are scarce which bring inconvenience to precise diagnosis and genetic counselling of the patients. Here, we present a novel mutation (c.948C>A, p.S316R) in the PIP4K2A gene in a female Hb H disease patient who displayed moderate anaemia and a relatively high Hb H level. Haematological analysis in her family members revealed that individuals carrying this mutation have upregulated β-globin expression, leading to a more imbalanced β/α-globin ratio and more Hb H inclusion bodies in peripheral red blood cells. According to functional experiments, the mutant PIP4K2A protein exhibits enhanced protein stability, increased kinase activity and a stronger regulatory effect on downstream proteins, suggesting a gain-of-function mutation. Moreover, introduction of the S316R mutation into HUDEP-2 cells increased expression of β-globin, further inhibiting erythroid differentiation and terminal enucleation. Thus, the S316R mutation is a novel genetic factor associated with β-globin expression, and the PIP4K2A gene is a new potential modifier gene affecting the α-thalassemia phenotype.

Fetal Hemoglobin H Hydrops Fetalis: Another Three Case Reports

We report three cases of fetalis hydrops associated with nondeletional α-thalassemia. Two cases were caused by hemoglobin (Hb) H-Quong Sz disease, and one caused by homozygous Hb Constant Spring. Fetal hydrops occurred in the late second trimester in all three cases. Our study indicates that for pregnancies at risk for fetal nondeletional Hb H disease, strict ultrasound follow-up is particularly important. Even without techniques of intrauterine transfusion treatment, early prenatal diagnosis can enable parents to make timely decisions.

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.

Molecular Basis and Genetic Modifiers of Thalassemia

Thalassemia syndromes are common monogenic disorders and represent a significant health issue worldwide. In this review, the authors elaborate on fundamental genetic knowledge about thalassemias, including the structure and location of globin genes, the production of hemoglobin during development, the molecular lesions causing α-, β-, and other thalassemia syndromes, the genotype-phenotype correlation, and the genetic modifiers of these conditions. In addition, they briefly discuss the molecular techniques applied for diagnosis and innovative cell and gene therapy strategies to cure these conditions.

Severity scoring system to guide transfusion management in pediatric non-deletional HbH

BACKGROUND

Hemoglobin (Hb) H is generally recognized as mild thalassemia, despite its actual phenotypic diversity. A disease severity scoring system to guide initiation of regular transfusion among severely affected pediatric patients has not previously been reported.

METHODS

Patients with HbH were classified into transfusion-dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT) as a surrogate for disease severity. Alpha-globin genotypes and relevant clinical parameters associated with TDT were identified. Univariate and multiple logistic regression analyses were performed to yield the most suitable severity scoring system.

RESULTS

From 246 patients with a median age of 14.3 (interquartile range 9.9-18.4) years initially enrolled into the study, the chance of having severe disease and developing TDT was remarkable only among patients with non-deletional HbH, for whom the scoring system was developed. Univariate and multiple logistic regression analyses resulted in three retained parameters associated with TDT, β-coefficients of which were used to develop the score. The final scoring system comprised age at diagnosis <2 years (score = 1), spleen size ≥3 cm (score = 1) and Hb at steady-state <7 (score = 4) or 7-8 g/dL (score = 3). A cutoff score ≥4 was associated with severe disease likely requiring regular transfusion (sensitivity 89.3%, specificity 81.4%), given regular transfusion resulted in maintained growth. The scoring system was validated in the second cohort of 77 non-deletional HbH, from which comparable sensitivity and specificity were obtained.

CONCLUSION

The newly developed scoring system was practical and helpful to highlight severely affected pediatric non-deletional HbH patients with potential needs of regular transfusion. This can be used as a guide for optimal treatment and disease monitoring in the future.

Prevalence and molecular characterization of common thalassemia among people of reproductive age in the border area of Guangxi-Yunnan-Guizhou province in Southwestern China

Objectives: Thalassemia, the most common global monogenetic disorder, is highly prevalent in southern China. Epidemiological and molecular characterization of thalassemia is important for designing appropriate prevention strategies in high-risk areas, especially the border area of Guangxi-Yunnan-Guizhou province in southwestern China.Methods: We recruited 38812 reproductive age couples and screened them for thalassemia. Routine blood tests as well as hemoglobin components and levels were evaluated. In addition, suspected thalassemia were identified by gap polymerase chain reaction (Gap-PCR) and PCR-based reverse dot blot (PCR-RDB).Results: The overall prevalence of thalassemia was 26.76%. Specifically, incidences of α-thalassemia, β-thalassemia, and concurrent α- and β-thalassemia were 17.52%, 6.92%, and 2.32%, respectively. The diagnosed α-thalassemia anomalies were associated with six gene mutations and 25 genotypes. The β-thalassemia anomalies were associated with 12 gene mutations and 15 genotypes. Moreover, among the 1799 concurrent mutated α- and β-thalassemia genes, 95 different genotypes were identified. Couples in which both partners were positive for α-thalassemia and β-thalassemia isotypes were 8.80% and 2.08%, respectively. The proportion of couples at a risk of having children with thalassemia major or intermedia was high.Conclusions: This study elucidates on the prevalence and molecular characterization of thalassemia in the border area of Guangxi-Yunnan-Guizhou provinces. These findings provide valuable baseline data for genetic counseling and prenatal diagnosis, with the overarching goal of preventing and controlling severe thalassemia.

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.

Molecular Heterogeneity of Hb H Disease in India

Alpha thalassemia is an autosomal recessive disorder caused by large deletions and/or point mutations in the α- globin genes. Hemoglobin H (Hb H) disease is most frequently due to deletion of three of the four α globin genes associated with variable clinical severity depending on the genotype. There are few reports on Hb H disease in Indians where genotyping has been done and we have reviewed the molecular and clinical heterogeneity of these cases. An electronic search for relevant articles was conducted using two journal databases, i.e., PubMed and Science Direct using the key words “Hb H Disease”, “Hemoglobin H”, “α-thalassemia”, “mutations”, “molecular heterogeneity”, “case reports” and “India”. This review was performed based on preferred reporting items for the systematic review and meta-analysis protocols (PRISMA-P) guidelines. The molecular spectrum of Hb H disease in Indians includes the most common [-α3.7, -α4.2, --SA, Poly A (AATAAA→AATA--), Hb Sallanches], rare [--SEA, --MED, IVS 1nt 1 (G→A), Hb Koya Dora, Hb Sun Prairie], very rare [Hb Iberia, Hb Seal Rock, Hb Zürich-Albisrieden] and novel [Codon 76 (+T) and --Kol] α-globin gene mutations inherited largely as compound heterozygotes with considerable clinical variability. The molecular diagnosis of Hb H disease is important for genetic counseling and management.

Outcomes of pregnancies complicated by haemoglobin H-constant spring and deletional haemoglobin H disease: A retrospective cohort study

The objective of the study was to compare the maternal and foetal outcomes of pregnancies complicated by Hb H-constant spring (HbH-CS) disease/deletional HbH (HbH-del) disease and low-risk pregnancies. A retrospective cohort research was undertaken on singleton pregnancies with Hb H-CS and Hb H-del diseases. The controls were randomly selected with a control-to-case ratio of 10:1. A total of 55 cases of HbH-CS disease, 231 cases of HbH-del disease and 2860 controls were compared. The mean gestational age at delivery and birthweight were significantly lower in the HbH-CS group than in the HbH-del and control groups. The clinical course of Hb H-CS was more severe than that of HbH-del disease. The rates of preterm birth, foetal growth restriction and low birthweight were significantly increased in the HbH-CS and Hb H-del groups. These rates were significantly greater in the HbH-CS group than in the H-del group. The maternal outcomes were not significantly different among the three groups. In conclusion, pregnancy worsens the course of HbH disease, more noticeably in HbH-CS disease. Hb H disease significantly increases the risk of adverse foetal outcomes, more noticeably in the HbH-CS group. Pregnancy is relatively safe for women with HbH disease.

Analysis of rare thalassemia genetic variants based on third-generation sequencing

Thalassemia is a group of common hereditary anemias that cause significant morbidity and mortality worldwide. However, precisely diagnosing thalassemia, especially rare thalassemia variants, is still challenging. Long-range PCR and long-molecule sequencing on the PacBio Sequel II platform utilized in this study could cover the entire HBA1, HBA2 and HBB genes, enabling the diagnosis of most of the common and rare types of thalassemia variants. In this study, 100 cases of suspected thalassemia were subjected to traditional thalassemia testing and third-generation sequencing for thalassemia genetic diagnosis. Compared with traditional diagnostic methods, an additional 10 cases of rare clinically significant variants, including 3 cases of structure variants and 7 cases of single nucleotide variations (SNVs) were identified, of which a case with − α^3.7 subtype III (− α^3.7III) was first identified and validated in the Chinese population. Other rare variants of 11.1 kb deletions (− 11.1/αα), triplicate α-globin genes (aaa^3.7/αα) and rare SNVs have also been thoroughly detected. The results showed that rare thalassemia variants are not rare but have been misdiagnosed by conventional methods. The results further validated third-generation sequencing as a promising method for rare thalassemia genetic testing.

CRISPR/Cas9 (D10A) nickase-mediated Hb CS gene editing and genetically modified fibroblast identification

This study investigated whether CRISPR/Cas9 (D10A) nickase-mediated gene editing can correct the aberrant Hb Constant Spring mutation (Hb CS or HBA2: c.427 T > C) in fibroblasts. Vectors for repairing the α-globin-encoding gene, HBA2:c.427 T > C mutation, includingthe CRISPR/Cas9(D10A)-sg plasmid and donor with homology arms, were constructed and used to perform gene editing in patient-derived fibroblasts. We subsequently analyzed the genetic correction, the gene editing efficiency and off-target effect. Sequencing analysis and the BamHI assay showed that HB CS mutant cells were repaired with Hb CS point mutations, the editing efficiency was 4.18%~9.34% and no off-target effects were detected. The results indicate that the HB CS mutant gene is effectively repaired by the CRISPR/Cas9 (D10A)system, which may enable truly personalized therapy for precise repair of α-thalassemia.

Genotype-phenotype correlation in patients with deletional and nondeletional mutations of Hb H disease in Southwest of Iran

We studied the alpha-globin gene genotypes, hematologic values, and transfusion-dependence of patients with Hb H disease. Molecular characterization of alpha-thalassemia was performed. We identified 120 patients with Hb H disease. Of these patients, 35 (29.16%) had deletional form of Hb H disease, and 85 (70.83%) had different form of non-deletional Hb H disease. The most frequently observed Hb H genotypes were --^Med/-α^3.7 in 33 patients (27.5%), α^CD19(-G) α^/αCD19(-G) α in 25 cases (20.83%), α^polyA2α/α^polyA2α in 15 (12.5%), and α^polyA1α/α^polyA1α in 13 (10.83%) respectively. The probability of receiving at least one transfusion blood in deletional form was observed in 3 of 35 (8.57%) patients which just seen in 3 of 33 (9%) patients with --^Med/-α^3.7 genotype. This form was also observed in 8 of 85 (9.4%) patients in non-deletional Hb H diseases which five of them had Med deletion in compound with alpha globin point mutations. Nondeletional Hb H disease was more severe than deletional Hb H disease requiring more blood transfusions. We can recommend that Med deletion in compound with alpha-globin point mutations, polyA1 and constant spring in homozygous form needs to be taken into consideration when offering counseling to high-risk couples.

Iron overload status in patients with non-transfusion-dependent thalassemia in China

Background:

Iron overload is one of the main factors that increase morbidity and mortality in patients with non-transfusion dependent thalassemia (NTDT).

Aim:

This study aimed at investigating the prevalence and severity of iron overload in Chinese NTDT patients.

Methods:

we analyzed serum ferritin (SF), liver iron concentration (LIC) and cardiac T2* in 178 Chinese NTDT in this cross-sectional study.

Results:

The median SF level was 996.00(27.15–19704.00) ng/ml and the median LIC value was 8.90(0.60–43.00) mg Fe/g dry weight (dw). The youngest patient with liver iron overload was 5 years old with 5.6 mg Fe/g dw in LIC. The median cardiac T2* was 33.06(7.46–75.08) ms. 6 patients had cardiac T2*⩽20ms. The patients with β thalassemia intermedia and HbE/β thalassemia showed a statistically significant lower Hb and higher values of SF and LIC than those of hemoglobin H disease patients. On multivariate logistic regression analysis, patients in ⩾ age 30-year old had a significant higher risk for iron overload (OR: 77.75, 95% CI: 8.76–690.49) in the age group. The detailed analysis of proportions of different LIC indicate in  > 30-year old group, 76.8% patients suffered from moderate and severe LIC.

Conclusion:

Our study provides a strong support for the novel findings that Chinese NTDT patients have a high prevalence of iron overload. The first assessment of MRI LIC should be performed as early as 5 years old. Then, NTDT patients  > 30 years old may suffer with a high burden of iron overload.

Advances in the management of α-thalassemia major: reasons to be optimistic

α-Thalassemia major (ATM) is a severe disease resulting from deletions in all 4 copies of the α-globin gene. Although it is usually fatal before birth, the advent of in utero transfusions has enabled survival of a growing number of children. Postnatal therapy consists of chronic transfusions or stem cell transplantation, similar to patients with β-thalassemia major. In this review, we discuss the experience with postnatal stem cell transplantation in patients with ATM, as well as the ongoing phase 1 clinical trial of in utero stem cell transplantation for this condition.

Screening of Some Indicators for Alpha-Thalassemia in Fujian Province of Southern China

Background

Carrier screening is the most effective means of controlling the prevalence of alpha-thalassemia. However, due to the differences in ethnic populations and genotypes, the distribution of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and hemoglobin A₂ (HbA₂) varies in different regions. This study aimed to examine screening efficiency of these indicators in different genotypes of alpha-thalassemia in Fujian Province, China.

Methods

The data of 13,294 subjects collected from May 2016 to December 2019 were reviewed. The participants were categorized as alpha-thalassemia group and negative-for-alpha-thalassemia group based on the results of the genetic analysis. The distribution of MCV, MCH, and HbA₂ in different groups was analysed statistically. And the screening efficiency of different indicators and schemes was compared in different genotypes. The positive criteria of MCV < 80fL, MCH < 27pg, and Hb A₂< 2.5% were applied.

Results

Among the 13,294 subjects, 2658 were alpha-thalassemia carriers. The genotypes of –^SEA/αα and -α^3.7/αα are the most prevalent with 63.9% and 21.9% in Fujian Province, China. There were significant differences in the distribution of the three indicators in different groups. The detection rate of the three indicators combined screening was 92.6%.

Conclusion

The distribution of the three indicators overlapped partly between alpha-thalassemia group and negative-for-alpha-thalassemia group. They showed significant differences in the median comparison of seven common genotypes. Combined screening with MCV, MCH and HbA₂ improved the detection rate of alpha-thalassemia. The results of this study provide a data basis for clinical laboratories and a reliable reference for clinical consultation.

Human m6A-mRNA and lncRNA epitranscriptomic microarray reveal function of RNA methylation in hemoglobin H-constant spring disease

The thalassemia of Hemoglobin H-Constant Spring disease (HbH-CS) is the most common type of Thalassemia in non-transfusion thalassemia. Interestingly, the clinical manifestations of the same genotype of thalassemia can be vastly different, likely due to epigenetic regulation. Here, we used microarray technology to reveal the epigenetic regulation of m⁶A in modifiable diseases and demonstrated a role of BCL2A1 in disease regulation. In this study, we revealed that methylating enzyme writers including METTL16, WTAP, CBLL1, RBM15B, and ZC3H13 displayed low expression and the demethylating enzyme ALKBH5, along with reader proteins including IGF2BP2 and YTHDF3 exhibited high expression. In addition, BCL2A1 was hypo-methylated and showed low expression. We also revealed that the BCL2A1 methylation level and IGF2BP2 expression were negatively correlated. Additionally, the mRNAs expression between ALKBH5 and IGF2BP2 were positively correlated. In HbH-CS, most genes were hypo-methylated. This included BCL2A1, which may play an important role in the process of red blood cell differentiation and development of HbH-CS. Moreover, the mRNA-M⁶A methylation status may be regulated by the demethylating enzyme ALKBH5 via IGF2BP2.

The serum ferritin levels and liver iron concentrations in patients with alphathalassemia is there a good correlation?

INTRODUCTION

Liver iron overload is common in patients with thalassemia. In patients with beta-thalassemia, the correlation between serum ferritin and liver iron concentration is well established. The correlation between serum ferritin levels and liver iron concentrations in patients with alpha-thalassemia remains limited.

METHODS

This is a cross-sectional study in patients with alpha-thalassemia aged ≥ 18 years old at Srinagarind Hospital, Khon Kaen University, Thailand. Liver iron concentration (LIC) was evaluated by the MRI-T2* technique. Linear logistic regression analysis was used to determine the correlation between serum ferritin levels and liver iron concentrations.

RESULTS

One hundred and thirty-one of the MRI-T2* measurements from 65 patients with alpha-thalassemia were evaluated. Patients with non-deletional alpha-thalassemia had higher LIC compared to patients with deletional alpha-thalassemia. The serum ferritin levels were relatively low at the same levels of LIC in patients with non-deletional alpha-thalassemia compared to deletional alpha-thalassemia.

CONCLUSIONS

The correlation of serum ferritin levels and LIC was modest and different among alpha-thalassemia genotypes. A different serum ferritin threshold is needed to guide iron chelation therapy in patients with alpha-thalassemia. Evaluation of liver iron concentration is necessary for patients with alpha-thalassemia, especially in patients with non-deletional alpha-thalassemia.

Coinherited Hemoglobin H/Constant Spring Disease and Heterozygous Hemoglobin Tak Causing Severe Hemolytic Anemia in a Thai Boy

Hemoglobin (Hb) H/Constant Spring disease is a common nondeletional Hb H disease, typically causing a more severe phenotype than the deletional Hb H disease counterpart. Hb Tak, resulting from a dinucleotide insertion (+AC) at codon 146 of beta-globin gene, has an increased oxygen affinity and usually presents with polycythemia. We studied a case of a 4-year-old Thai boy with a severe, early-onset anemia. To our knowledge, he is the first reported patient with Hb H/Constant Spring disease and heterozygous Hb Tak. Trio-whole-exome sequencing does not identify other genetic variants that may contribute to the severity of anemia. The observation suggests that coinherited Hb H/Constant Spring and heterozygous Hb Tak lead to severe hemolytic anemia.

Successful Implementation of Newborn Screening for Hemoglobin Disorders in the Philippines

The Philippine newborn bloodspot screening (NBS) program began in 1996 with 24 hospitals and was formalized by legislation in 2004. The NBS panel was recently expanded to include a number of additional hereditary congenital conditions. Expertise and experiences from other NBS programs already screening for hemoglobinopathies were essential to its successful integration into the ongoing dried bloodspot NBS program in the Philippines. Building on clinical experiences and population data from Filipinos born in California, USA, hemoglobinopathies (including thalassemias) were selected for inclusion in the expanded screening panel. Hemoglobinopathy NBS, using high performance liquid chromatography, was implemented in a stepwise manner into the seven regional NBS screening laboratories. A central university laboratory provides confirmatory testing using both capillary electrophoresis and molecular methodologies. NBS results indicating carriers are followed up with educational fact sheets, while results of presumptive disease are referred for confirmatory testing and follow-up with a hematologist. Long-term care is provided through newborn screening continuity clinics across the country. Hemoglobinopathy NBS is now included in the national insurance package and screening uptake continues to increase nationally, exceeding 90% of all newborns in 7400+ hospitals and birthing centers nationwide prior to the COVID-19 pandemic.

Correlation Between Serum Ferritin and Viral Hepatitis in Thalassemia Patients

Serum ferritin is an acute phase protein; importantly, its level is noticeably increased in response to iron overload and systemic inflammation. The iron overload status in thalassemia patients has been recognized as a potential way to measure liver iron concentration (LIC) levels using magnetic resonance imaging (MRI). The aim of this study was to investigate the effect of chronic viral hepatitis on the level of serum ferritin in patients with thalassemia. A cross-sectional study was conducted involving chronic viral hepatitis infection. Mean serum ferritin and LIC levels were recorded. The LIC values were used to divide the patients into two groups; a higher LIC group (>5 mg Fe/g) and a lower LIC group (<5 mg Fe/g). Mean serum ferritin levels were then compared between the two LIC groups. We identified 32 thalassemia patients comprising of 13 chronic viral hepatitis patients, seven patients with hepatitis B virus (HBV), and six patients with hepatitis C virus (HCV). With regard to the group with higher LIC values, the mean serum ferritin levels in the hepatitis group were significantly higher than for those in the non hepatitis group (1776 ± 488 vs. 967 ± 860 ng/mL, p = 0.03). Furthermore, the linear correlation between the mean serum ferritin levels and the viral load in the non transfusion-dependent thalassemia (NTDT) group were found to be significantly correlated (r = 0.7, p = 0.04). Chronic viral hepatitis was determined to be a possible casualty of disproportionately high ferritin levels in the NTDT group.

First Report of Nondeletional Hb H Disease Caused by an α2-Globin Gene Mutation: HBA2: c.184A>T

We report a rare mutation, HBA2: c.184A>T on the α2-globin gene, detected in a Chinese proband who presented with Hb H disease and a mild anemia. This frameshift mutation results in a premature termination of translation at position 61 of the α2-globin gene. Carriers of this mutation showed a borderline microcytic hypochromia. Our study indicates the importance of screening nondeletional α-thalassemia (α-thal) in areas with a particularly high prevalence of thalassemia such as in Southern China, especially for couples with one partner carrying an α⁰-thal deletion.

[Rare thalassemia caused by novel nucleotide variants in the globin gene: four case reports and literature review]

Objective: To analyze the DNA sequences and clinical phenotypes of four cases with rare thalassemia to improve its recognition and accurate diagnosis. Methods: The DNA sequence characteristics of four cases with rare thalassemia diagnosed from May 2014 to December 2019 were retrospectively analyzed, and related literature was reviewed. Results: The results of the routine gene test for thalassemia indicated that the common three type of deletion and three point mutations in hemoglobin alpha 1/2 (HBA1/A2) , and 16 point mutations in hemoglobin beta (HBB) gene were unable to be detected in cases 1-3, and case 4 was--SEA. However, the results of HBA1/A2 and HBB whole-genome sequencing revealed that the four cases had a point mutation of HBB:c.347C>A, HBB:c.1A>G, HBB:c.393T>G, and HBA2: c.301-1G>A (IVS II-142 G>A) , respectively. Meanwhile, the father, aunt, and grandfather of case 2 carried the HBB:c.1 A>G heterozygous point mutation. Conclusion: The novel mutations in HBB and HBA2 genes, resulting in a rare thalassemia, were revealed. Among them, the HBB:c.347C>A, HBB:c.1A>G, and HBA2:c.301-1G>A (IVS II-142 G>A) mutations were first reported in Chinese patients with thalassemia. Contrarily, HBB:c.393T>G mutation has not yet been recorded in the databases of human hemoglobin variants and thalassemia. The discovery of these novel nucleotide variants in this study would enrich the DNA mutation gene database of thalassemia.

Mild α-Thalassemia Caused by a Mosaic α-Globin Gene Mutation

We describe a new α-globin chain variant in a Chinese subject. This novel variant, with a Val→Met substitution at codon 93 of the α-globin chain, has been named Hb Qingcheng (HBA1: c.280G>A) for where the proband was born. A woman with somatic mosaicism for Hb Qingcheng presented with the phenotype of mild α-thalassemia (α-thal).

Chronic Hemolysis May Adversely Affect Skeletal Health. A Cross-Sectional Study of a Pediatric Population

Hereditary hemolytic disorders cause ineffective erythropoiesis and bone marrow hyperplasia. Little is known about their effect on growth and skeletal health. The aim of this study was to evaluate growth, bone and body composition of non transfusion-dependent (NTD) pediatric patients with chronic hemolysis. A detailed history and clinical examination, dual-energy X-ray absorptiometry (DXA) of the lumbar spine (LS) and total body less head (TBLH) and bone turnover markers were performed. Thirty-nine patients (22 males and 17 females, 20 prepubertal), aged 11.4 ± 3.6 years [14 had β-thalassemia intermedia (β-TI), 17 α-thalassemia (α-thal) and eight hereditary spherocytosis (HS)] were evaluated. Fifty-seven previously studied controls were used for statistical analysis. The patients had lower weight and body mass index (BMI) (Z-scores -0.2 and -0.3, respectively, p < 0.05). Post-traumatic fractures were reported by 28.0% of the patients. Compared to controls, they had lower lumbar and subcranial bone mineral density (BMD), as well as reduced fat mass (FM), whereas muscle mass was not affected. One in three patients had low vitamin D and there was increased bone resorption and reduced bone formation. Correlations between different parameters revealed a potential role of osteocalcin, hemoglobin (Hb) and lactate dehydrogenase (LDH) as prognostic markers for bone health, in the setting of chronic hemolysis. Hereditary spherocytosis (HS) patients were the least affected in terms of growth and bone profile. Chronic hemolysis may lead to impaired growth and bone health, even in young, NTD patients. The degree of hemolysis determines bone health risk. Regular surveillance of bone health is justifiable.

EF Bart's Disease with Coinheritance of Gγ-XmnI and Aγ-Globin Polymorphisms: A Case of Nontransfusion-Dependant Thalassemia

EF Bart's disease is a rare form of nontransfusion-dependant thalassemia (NTDT) due to the coinheritance of homozygous hemoglobin E (β^E/β^E) genotype with hemoglobin H disease. These individuals are routinely found to have thalassemia intermedia with moderate anemia, increased hemoglobin Bart's and hemoglobin F on electrophoresis. The contribution of hemoglobin F-inducing polymorphisms in this disease has not been described previously. Here, we describe the hematological profile in a young child with coinheritance of Gγ-XmnI and Aγ-globin gene polymorphisms in EF Bart's disease. Interestingly, in this rare form of NTDT, normal HbF and elevated HbA2 were noted.

Genotype-phenotype correlation of HbH disease in northern Iraq

BACKGROUND

HbH disease results from dysfunction of three, less commonly two, α-globin genes through various combinations of deletion and non-deletion mutations. Characterization of the mutations and the underlying genotypes is fundamental for proper screening and prevention of thalassaemia in any region. The aim of this study was to explore the genetic arrangements of HbH disease and to correlate the genotypes with the clinical phenotypes.

METHODS

A total of 44 HbH disease patients were enrolled in this study. They were clinically and haematologically assessed. The patients were tested for 21 common α-globin gene mutations using multiplex PCR and reverse hybridization. According to the genotype, the patients were categorized into two separate sub-groups, deletion and non-deletion types HbH disease.

RESULTS

Within the studied HbH disease patients, eight different α-globin gene mutations were detected in nine different genetic arrangements. The --^MED and -α^3.7 deletions were the two most frequently encountered mutations (37.5 and 35.2% respectively). Patients with deletion genotypes constituted 70.4%. The most common detected genotype was --^MED/-α^3.7 (59.1%), followed by α^poly-A1α/α^poly-A1α (13.6%). For the first time, coinheritance of two relatively mild mutations (-α^3.7/αα^Adana) was unpredictably detected in a 1.5 year-old child with Hb of 7.1 g/dL.

CONCLUSION

The HbH disease patients' clinical characteristics were variable with no ample difference between the deletion and non-deletion types. These results can be of benefit for the screening and management of thalassaemia in this region.

Molecular epidemiological and hematological profile of thalassemia in the Dongguan Region of Guangdong Province, Southern China

Background

Thalassemia is a common inherited hematological disease in tropical and subtropical regions. This study aimed to investigate the mutation spectrum of thalassemia in the Dongguan region of southern China and comprehensively analyze hematologic features of thalassemia carriers with various types of globin mutations.

Methods

A hematological screening including hematological indices such as mean corpuscular volume (MCV), mean corpuscular hemoglobin content (MCH), and mean corpuscular hemoglobin concentration (MCHC) was conducted in 19 442 people from Dongguan region, Guangdong province of China. Then, 4891 suspected thalassemia carriers were further investigated by genetic analysis of combined NGS and gap‐PCR.

Results

Totally, 2319 (11.9%) cases were diagnosed as carriers of thalassemia, of which 1483 cases (7.6%) were α‐thalassemia, 741 cases (3.8%) were β‐thalassemia, and 95 cases (0.5%) were co‐inheritance of α‐ and β‐thalassemia. In α‐thalassemia carriers, the phenotypic severity increases with the number of nonfunctional α‐globin genes. The patients with –^SEA/α^WSα genotype have less severe clinical phenotypes than those with other Hb H diseases. As for β‐thalassemia, the MCV and MCH in both β⁰ and β⁺ carriers are markedly reduced.

Conclusions

This is the first comprehensive molecular epidemiological survey and hematological profiling of thalassemia in Dongguan area. This study will be benefit for genetic counseling in the clinic and may help pediatricians to make a correct diagnosis of different types of thalassemia.

Newborn Screening Practices and Alpha-Thalassemia Detection - United States, 2016

Alpha-thalassemia comprises a group of inherited disorders in which alpha-hemoglobin chain production is reduced. Depending on the genotype, alpha-thalassemia results in moderate to profound anemia, hemolysis, growth delays, splenomegaly, and increased risk for thromboembolic events; certain patients might require chronic transfusions. Although alpha-thalassemia is not a core condition of the United States Recommended Uniform Screening Panel* for state newborn screening programs, methodologies used by some newborn screening programs to detect sickle cell disease, which is a core panel condition, also detect a quantitative marker of alpha-thalassemia, hemoglobin (Hb) Bart's, an abnormal type of hemoglobin. The percentage of Hb Bart's detected correlates with alpha-thalassemia severity. The Association of Public Health Laboratories' Hemoglobinopathy Workgroup conducted a survey of state newborn screening programs' alpha-thalassemia screening methodologies and reporting and follow-up practices. Survey findings indicated that 41 of 44 responding programs (93%) report some form of alpha-thalassemia results and 57% used a two-method screening protocol. However, the percentage of Hb Bart's used for thalassemia classification, the types of alpha-thalassemia reported, and the recipients of this information varied widely. These survey findings highlight the opportunity for newborn screening programs to revisit their policies as they reevaluate their practices in light of the recently released guideline from the Clinical and Laboratory Standards Institute (CLSI) on Newborn Screening for Hemoglobinopathies (1). Although deferring to local programs for policies, the report used a cutoff of 25% Hb Bart's in its decision tree, a value many programs do not use. Standardization of screening and reporting might lead to more timely diagnoses and health care services and improved outcomes for persons with a clinically significant alpha-thalassemia.

Early development of decreased β-cell insulin secretion in children and adolescents with hemoglobin H disease and its relationship with levels of anemia

BACKGROUND

Diabetes mellitus (DM) associated with iron overload has been reported among adults with transfusion-dependent thalassemia and those with non-transfusion-dependent thalassemia (NTDT), especially in β-thalassemia disease. However, little is known about glucose metabolism and how early its dysregulation can develop in α-thalassemia hemoglobin H (Hb H) disease, which is one of the most common types of NTDT worldwide.

PROCEDURE

We prospectively calculated glucose metabolism index in 40 patients (aged 10-25 years) with Hb H disease. Glucose metabolism data were compared between patients with deletional versus nondeletional Hb H, and between patients with normal versus abnormal insulin secretion/sensitivity.

RESULTS

Despite normal glucose tolerance in all patients, 52.5% had abnormal insulinogenic index indicating decreased β-cell insulin secretion. Patients with functional hemoglobin < 8 g/dL had significantly higher percentages of abnormal insulinogenic index. There was no significant difference in abnormal insulinogenic index between deletional and nondeletional Hb H.

CONCLUSION

Decreased β-cell insulin secretion is highly prevalent among children and adolescents with Hb H disease, and it is associated with levels of functional anemia at baseline, but not with the type of Hb H disease. This result warrants heightened awareness among hematologists due to potentially increased risk of DM later in life.

[Serum level of soluble transferrin receptor in children with hemoglobin H disease]

OBJECTIVE

To investigate the serum level of soluble transferrin receptor (sTfR) and its association with the degree of anemia in children with hemoglobin H (HbH) disease.

METHODS

A total of 55 children with HbH disease were enrolled as the HbH group, and 30 healthy children were enrolled as the control group. The HbH group was further divided into a deletional HbH disease group and a non-deletional HbH disease group. A retrospective analysis was performed for hematological parameters and serum sTfR level in all groups.

RESULTS

Of the 55 children with HbH disease, 39 had deletional HbH disease and 16 had non-deletional HbH disease. Compared with the control group, the deletional and non-deletional HbH disease groups had significantly lower hemoglobin (Hb), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) and a significantly higher serum level of sTfR. Compared with the deletional HbH disease group, the non-deletional HbH disease group had significantly lower red blood cell count (RBC) and Hb level and significantly higher MCV, MCH, and serum sTfR level. In children with HbH disease, serum sTfR level was negatively correlated with RBC and Hb level (r=-0.739 and -0.667 respectively, P<0.05) and positively correlated with MCV and MCH (r=0.750 and 0.434 respectively, P<0.05).

CONCLUSIONS

Serum sTfR level is associated the degree of anemia in children with HbH disease, and sTfR may be a target for the treatment of HbH disease.

Estimating the burden of α-thalassaemia in Thailand using a comprehensive prevalence database for Southeast Asia

Severe forms of α-thalassaemia, haemoglobin H disease and haemoglobin Bart’s hydrops fetalis, are an important public health concern in Southeast Asia. Yet information on the prevalence, genetic diversity and health burden of α-thalassaemia in the region remains limited. We compiled a geodatabase of α-thalassaemia prevalence and genetic diversity surveys and, using geostatistical modelling methods, generated the first continuous maps of α-thalassaemia mutations in Thailand and sub-national estimates of the number of newborns with severe forms in 2020. We also summarised the current evidence-base for α-thalassaemia prevalence and diversity for the region. We estimate that 3595 (95% credible interval 1,717–6,199) newborns will be born with severe α-thalassaemia in Thailand in 2020, which is considerably higher than previous estimates. Accurate, fine-scale epidemiological data are necessary to guide sustainable national and regional health policies for α-thalassaemia management. Our maps and newborn estimates are an important first step towards this aim.

Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).