Screening and genetic diagnosis of haemoglobin disorders

Regional Prevalence of Hemoglobin C Across Saudi Arabia: An Epidemiological Survey

INTRODUCTION

HbC is a common structural hemoglobinopathy especially in West Africa. Prevalence and regional distribution of HbC in Saudi Arabia are widely undocumented. Patients with homozygous HbC disease may have mild hemolytic anemia whereas combination with hemoglobin S (HbS) leads to a clinically severe phenotype.

AIM

The current epidemiological study, considered the largest from Saudi Arabia, aimed to evaluate the regional prevalence of the HbC variant among the couples participating in the premarital screening program from 2011 to 2018.

METHODS

Data from the PMSGC program were obtained for premarital screening and genetic counseling. The collected data were then entered into the SEHA platform, a centralized electronic repository for the 13 designated regions in Saudi Arabia. Hemoglobin electrophoresis samples are analyzed using either HPLC, capillary electrophoresis, or a combination of both methods to confirm the presence of abnormal hemoglobin bands.

RESULTS

This study included 1,871,184 individuals from 2011 to 2018. Of those, 49.8% were males and 50.2% were females. 112,618 (6.0%) had an abnormal test. Total number of Hb C cases were 778 (0.04%). HbC trait (HbAC) was detected in 764 participants while homozygous HbC (HbCC) and combined heterozygous (HbSC) were found in 9 and 5 cases, respectively. The regions near the Red Sea have higher rates than the central and eastern regions.

CONCLUSION

HbC is a rare variant in Saudi Arabia with varying regional frequencies. HbC variant is more common in Mecca and Madina regions. The geographic area of HbC distribution differs from the areas with high prevalence of HbS, which explains why HbSC disease cases are overwhelmingly rare.

Molecular characterisation of sickle cell disease and classification of major haplotypes associated with the β-globin cluster (HBB gene) by means of SNP marker sequencing in a group of samples from Bolívar, Colombia

BACKGROUND

Colombia has a mestizo population and the prevalence of haemoglobin variants varies according to each region, but heterozygous carriers can be found in all of them.

AIM

To characterise sickle cell disease (SCD) haematologically, biochemically, and molecularly, and detect classic haplotypes by DNA sequencing in a group of samples from Bolívar, Colombia.

SUBJECTS AND METHODS

Blood samples were collected after informed consent from volunteers from eight communities in the Bolívar department, plus samples from the Pacific region, Providencia Island, and Bogotá were included. Data were obtained from: (1) haematological analyses; (2) biochemical tests: dHPLC was used to determine haemoglobin (Hb); and (3) DNA sequencing data through five SNPs.

RESULTS

101 samples were identified by rs334 through Sanger's Sequencing, structural haemoglobinopathies HbAS (34.65%), HbSS (2.97%) and HbAC (1.98%) were found. When contrasting the Hb identification results between SNP rs334 Vs. dHPLC/Isoelectric Focusing (IEF), a coincidence was found in 39/43 samples analysed, therefore, when comparing these techniques, a significant correlation was found (Pearson's correlation coefficient r = 0.998). 26 samples previously analysed by rs334 were classified into classical haplotypes CAR (50.0%), BEN (30.76%), CAM (7.69%), SEN (3.84%), and ATP-I (7.69%).

CONCLUSIONS

SCD characterisation and SNPs-based classification through Sanger's DNA sequencing have not been performed before in Colombia. The results of this work will make it possible to expand the data or records of carriers and those affected, which will benefit patients and their families.

Spectrum of Beta-Thalassemia Mutations in Potential Carriers with Microcytic Hypochromic Anemia from Mazandaran and Golestan, Northern Provinces of Iran

Introduction

β-Thalassaemia is the most common genetic disorder and is considered as a major public health concern in Iran. Different countrywide studies have shown a heterogeneous mutational basis of β-thalassaemia with different frequencies in each area. This study is aimed at investigating the common and rare mutations in Mazandaran and Golestan, northern provinces of Iran.

Methods

5425 microcytic and hypochromic individuals were investigated from Mazandaran and Golestan provinces. From these, 1323 beta carrier or affected individuals were selected where 938 persons were from Mazandaran and 385 people were from Golestan province, respectively.

Result

53 different mutations were identified, IVSII-1 (G>A) was the most common (59.14%) followed by Cd 22/23/24 (-7 bp) (5.34%), Cd 8 (-AA) (4.93%), Cd30 (G>A) (4.00%), and IVSI-5 (G>C) (3.70%) with a total of 77.11% in Mazandaran Province, respectively. In Golestan Province, IVSI-5 (G>C) was the most frequent (44.62%) followed by IVSII-1 (G>A) (27.18%), Cd 15 (TGG>TAG) (4.36%), Fr 8/9(+G) (3.85%), and Cd 8(-AA) (2.05%) with a total of 82.06%, respectively. From the 53 different mutations, 22 numbers have been observed in both provinces. Two deletions of the beta gene named Sicilian and Asian-Indian have been detected in Mazandaran with a frequency of 0.72% each.

Conclusion

The 53 different mutations identified in this study were the most ever reported mutations in the country. Due to diversity of different ethnic groups, there are many varieties of mutation in beta globin gene in Iran. It could be assumed that both founder effect and natural selection caused by migration from neighboring areas have complemented each other to produce the high frequency of unique alleles within each region.

α- and β-Globin Gene Mutations in Individuals with Hemoglobinopathies in the Chattogram and Sylhet Regions of Bangladesh

Hemoglobinopathies, including α- and β-thalassemias and sickle cell disease, are among the most widely disseminated hereditary blood disorders worldwide. Bangladesh is considered a hotspot for hemoglobinopathies, and these diseases cause a significant health concern in the country. However, the country has a dearth of knowledge on the molecular etiology and carrier frequency of thalassemias, primarily due to a lack of diagnostic facilities, limited access to information, and the absence of efficient screening programs. This study sought to investigate the spectrum of mutations underlying hemoglobinopathies in Bangladesh. We developed a set of polymerase chain reaction (PCR)-based techniques to detect mutations in α- and β-globin genes. We recruited 63 index subjects with previously diagnosed thalassemia. Along with age- and sex-matched control subjects, we assessed several hematological and serum indices and genotyped them using our PCR-based methods. We identified that parental consanguinity was associated with the occurrence of these hemoglobinopathies. Our PCR-based genotyping assays identified 23 HBB genotypes, with the codons 41/42 (-TTCT) (HBB: c.126_129delCTTT) mutation leading the spectrum. We also observed the presence of cooccurring HBA conditions, of which the participants were not aware. All index participants in this study were on iron chelation therapies, yet we found they had very high serum ferritin (SF) levels, indicating inefficient management of the individuals undergoing such treatments. Overall, this study provides essential information on the hemoglobinopathy mutation spectrum in Bangladesh and highlights the need for nationwide screening programs and an integrated policy for diagnosing and managing individuals with hemoglobinopathies.

Impact of age-dependent red blood cell parameters on α-globin gene genotyping in children

When screening for α-thalassemia in children, adult cut-offs for mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) are generally applied to guide genetic evaluation. However, the normal ranges for MCV and MCH are lower in children than in adults, so we hypothesized that using age-matched cut-offs could lead to a more rational diagnostic strategy. The aim of this study was to evaluate if age-matched cut-offs could be applied advantageously. Data on children referred to a hemoglobin fractionation at the Department of Clinical Biochemistry, Aarhus University Hospital between 2016-2021 were identified in the laboratory information system. α-globin gene (HBA1/HBA2) genotyping was performed using multiplex gap-polymerase chain reaction. A total of 387 children were identified. HBA1/HBA2-genotyping was performed in 207 children (53%), and α-thalassemia was diagnosed in 47 children (23%) with -α^3.7/αα being the predominant genotype (13%). We found that 23 children had MCV and MCH levels in the normal age-matched range, and two of these children (9%) were α⁺ thalassemia carriers with three functional α-globin genes. Using age-specific cut-off levels resulted in a reduction of 23 (11%) genotypes performed. In conclusion, applying age-matched cut-offs for MCV and MCH when screening children for α-thalassemia lead to 11% fewer genotypes performed while 9% carriers of α⁺ thalassemia (of the medically innocuous genotype -α^3.7/αα) would have been overlooked.

Clinical Presentation of Hemoglobin C in Albania: Case Series

The presence of HbC is a rare event in Europe and Mediterranean region where thalassemia and HbS are more frequently encountered. The rarely diagnosed cases are linked with the migration from West-Central Africa. Albania is one of the Mediterranean countries where inherited haemoglobin disorders are considerably widespread. Studies have shown the presence of thalassemia, sickle cell disease and sporadic cases of Hb O-Arab, Hb Lepore especially in the areas where malaria has been endemic. In 2006 we identified the first case with HbSC disease and until 2020 we have found 15 cases with HbC variant. In this study we have collected and analyzed the laboratory and clinical data of HbC cases. Our data support reports that HbC combinations with HbS and beta thalassemia are clinically important. Our data confirm the presence of the HbC variant in ex-malaric areas where thalassemia and HbS are quite widespread. 

Using DNA testing for the precise, definite, and low-cost diagnosis of sickle cell disease and other Haemoglobinopathies: findings from Tanzania

Background

Sickle cell disease (SCD) is an important cause of under-five mortality. Tanzania is the 5th country in the world with the highest births prevalence of SCD individuals. Significant advances in the neonatal diagnosis of SCD using rapid point-of-care testing have been made. However genetic confirmation is still required for positive cases, in uncertain cases, in multiply transfused patients, to resolve compound heterozygosity (Hb S/ β⁰ Thal or Hb S/ β⁺ thal) not uncommon in the coastal regions of East Africa and increasingly also for pre-marital counselling and potentially for future curative approaches such as gene therapy. The currently available DNA tests are prohibitively expensive. Here, we describe an easy-to-use, affordable and accurate β-globin sequencing approach that can be easily integrated within existing NBS for SCD and other haemoglobinopathies especially in Low- and Middle-income Countries.

Aim

To evaluate an affordable DNA technology for the diagnosis of Sickle cell disease and other haemoglobinopathies in a resource-limited setting.

Methods

Laboratory-based validation study was conducted by Muhimbili University of Health and Allied Sciences and the University of Oxford involving sequencing of the entire β -haemoglobin locus using the Oxford Nanopore MinION platform. A total number of 36 Dried blood spots and whole blood samples were subjected to conventional protein-based methods (isoelectric focusing, HPLC), and/or sequenced by the Sanger method as comparators.

Results

Sequencing results for SCD using the MinION were 100% concordant with those from the Sanger method. In addition, the long-read DNA sequencing method enabled the resolution of cases with unusual phenotypes which make up 1% of all children in Tanzania. The cost is £11/ sample for consumables, which is cheaper compared to other sequencing platforms.

Conclusions

This is the first report of a comprehensive single DNA assay as a definitive diagnostic test for SCD and other haemoglobinopathies. The test is fast, precise, accurate and affordable.

A high frequency of Gilbert syndrome (UGT1A1*28/*28) and associated hyperbilirubinemia but not cholelithiasis in adolescent and adult north Indian patients with transfusion-dependent β-thalassemia

Hyperbilirubinemia and pigment gallstones are frequent complications in transfusion-dependent β-thalassemia (TDβT) patients. Bilirubin production and clearance are determined by genetic as well as environmental variables like ineffective erythropoiesis, hemolysis, infection-induced hepatic injury, and drug- or iron-related toxicities. We studied the frequency of the Gilbert syndrome (GS), a common hereditary cause of hyperbilirubinemia in 102 TDβT patients aged 13-43 years (median 26 years). Total and unconjugated hyperbilirubinemia were frequent (81.4% and 84.3% patients respectively). Twenty (19.6%) patients showed total bilirubin > 3.0 mg/dL; 53 (51.9%) had an elevation of either alanine or aspartate aminotransferase, or alkaline phosphatase liver enzymes. Nineteen (18.6% of the 92 tested) were positive for hepatitis B or C, or HIV. The mean total and unconjugated bilirubin levels and AST, ALT, and ALP levels in patients positive for hepatitis B or C were not significantly different from negative cases. Eighteen patients (17.7%) had GS: homozygous (TA)7/7 UGT1A1 promoter motif (the *28/*28 genotype), 48 (47.1%) were heterozygous (TA)6/7. Total + unconjugated bilirubin rose significantly with the (TA)7 allele dose. Fourteen (13.7%) patients had gallstones. There was no significant difference in total/unconjugated bilirubin in patients with/without gallstones and no significant differences in frequencies of gallstones within the three UGT1A1 genotypes. This largest study in Indian TDβT patients suggests that GS should be excluded in TDβT cases where jaundice remains unexplained after treatable causes like infections, chelator toxicity, or transfusion-related hemolysis are excluded. GS was not associated with gallstones, possibly due to a lower incidence of cholelithiasis overall, a younger age cohort, or other environmental factors.

Reproductive health issues in female patients with beta-thalassaemia major: a narrative literature review

β-thalassaemia major (BTM) has a high prevalence worldwide and is associated with considerable morbidity and mortality. The aim of this review is to provide an illustrative overview of the reproductive health and pregnancy related issues in females with β-thalassaemia. A literature search was performed in four international databases (1980-2018) to identify the potentially relevant articles. Common reproductive health disorders are hypo-gonadotrophic hypogonadism, infertility, delayed or absent sexual development, diabetes, hypothyroidism, hypoparathyroidism, osteopenia, preeclampsia, gestational hypertension, polyhydramnios, oligohydramnios, thrombosis, renal failure, peripheral vascular resistance, placenta previa, pleural effusion and pulmonary hypertension. Many of those aspects are related to iron overload and to ineffective erythropoiesis. Foetal complications include neural tube defects, abnormalities in different organs, spontaneous abortion, foetal loss, preterm birth, foetal growth restriction and low birth weight. Antenatal screening and accurate genetic prenatal examinations are effective measures to early diagnosis of thalassaemia and a detailed plan for management of pregnancies in BTM is important for favourable maternal and foetal outcome.

Prediction of K562 Cells Functional Inhibitors Based on Machine Learning Approaches

BACKGROUND

β thalassemia is a common monogenic genetic disease that is very harmful to human health. The disease arises is due to the deletion of or defects in β-globin, which reduces synthesis of the β-globin chain, resulting in a relatively excess number of α-chains. The formation of inclusion bodies deposited on the cell membrane causes a decrease in the ability of red blood cells to deform and a group of hereditary haemolytic diseases caused by massive destruction in the spleen.

METHODS

In this work, machine learning algorithms were employed to build a prediction model for inhibitors against K562 based on 117 inhibitors and 190 non-inhibitors.

RESULTS

The overall accuracy (ACC) of a 10-fold cross-validation test and an independent set test using Adaboost were 83.1% and 78.0%, respectively, surpassing Bayes Net, Random Forest, Random Tree, C4.5, SVM, KNN and Bagging.

CONCLUSION

This study indicated that Adaboost could be applied to build a learning model in the prediction of inhibitors against K526 cells.

Compound Heterozygote of Hb S (HBB: c.20A>T)/Hb Westdale (HBB: c.380_396delTGCAGGCTGCCTATCAG): Report of Four Cases from Odisha State, India

We report four cases of compound heterozygotes for Hb S (HBB: c.20A>T) and a rare β⁰-thalassemia (β⁰-thal) mutation, Hb Westdale (HBB: c.380_396delTGCAGGCTGCCTATCAG), characterized by a 17 bp deletion between codons 126 to 131 in exon 3 of the β-globin gene of human hemoglobin (Hb) confirmed by direct β-globin gene sequencing. All four cases were from four unrelated families belonging to the Agharia caste, an endogamous ethnic community of the Sundargarh and Jharsuguda districts of Odisha State, India. Detailed observations indicated that all four cases of Hb S/Hb Westdale were clinically severe. On family screening, six family members were found to be heterozygous for Hb Westdale and were asymptomatic. Deletional α-thalassemia (α-thal) and XmnI polymorphism were studied for all the Hb Westdale cases. The Hb S/Hb Westdale cases had an early median age at onset of symptoms and presentation, more requirement of blood transfusions, splenomegaly and hepatomegaly and were found to be clinically more severe when compared with the Hb S-β-thal with IVS-I-5 (G>C) (HBB: c.92 + 5G>C) cases. Overall, the findings indicate that this rare and hitherto unreported compound heterozygosity of Hb S/Hb Westdale is a clinically significant hemoglobinopathy and its finding in a large endogamous community of Odisha State, India will have important implication in the epidemiology and understanding of the clinical spectrum of sickle cell disease in Indian context and prenatal diagnosis.

Prenatal diagnosis of a case with SEA-HPFH deletion thalassemia with whole HBB gene deletion

OBJECTIVE

The thalassemias is a group of hereditary disorders with impaired production of functional hemoglobin. In this report we described a rare case of compound heterozygous mutation of South-East Asia type hereditary persistence of fetal hemoglobin (SEA-HPFH) and β -thalassemia that allowed prenatal diagnosis to be performed in a subsequent pregnancy in the family.

CASE REPORT

The father showed a SEA-HPFH thalassemia trait phenotype, while his genotype revealed that he was heterozygous for the SEA-HPFH deletion; The mother genotype was heterozygote for IVS-II-654 mutation; the second child had co-inherited both parental mutations and was, thus, a compound heterozygote for β-thalassemia (IVS-II-654)/SEA-HPFH deletion. His phenotype was intermediate β-thalassemia. Prenatal genotyping of a fetal sample during the third pregnancy confirmed the fetus was only heterozygote for SEA-HPFH deletion and the parents elected to continue the pregnancy.

CONCLUSION

We described the clinical and molecular characterization of the first detected case of compound β-Thalassemia/SEA-HPFH deletion in Northern Vietnam. The report also highlighted the accuracy and necessity of mutation screening for families with thalassemia to inform accurate genetic counseling and targeted prenatal diagnosis when desired.

The Results of Hemoglobin Variant Analysis in Patients Revealing Microcytic Erythrocytosis on Complete Blood Count

Background

Microcytic erythrocytosis is an underrecognized and underevaluated complete blood count (CBC) finding. The literature pertaining to the determination of its etiology specifically by hemoglobin variant analysis is limited.

Methods

We performed hemoglobin variant analysis by high performance liquid chromatography on 137 patients who revealed microcytic erythrocytosis on CBC, and reviewed the results for the diagnosis of hemoglobin-associated disorders.

Results

A diagnosis of thalassemia trait and/or a hemoglobinopathy was established in 93 of 137 (67.9%) patients. Amongst these, ß-thalassemia trait topped the list with 69 cases (74.1%), followed by hereditary persistence of fetal hemoglobin with 5 cases (5.5%), Hemoglobin E disease with 4 cases (4.3%), and ∂/ß-thalassemia with 2 cases (2.1%). Compound heterozygous conditions with 1 or more hemoglobinopathies and/or thalassemias were diagnosed in 13 cases (14.0%). Abnormal hemoglobins in the compound heterozygosity group included C, S, HPFH, and 2 unknowns.

Conclusion

Hemoglobin variant analysis provided a very high positive yield in determining the etiology of microcytic erythrocytosis.

Consensus Predictive Model for Human K562 Cell Growth Inhibition through Enalos Cloud Platform

β-Thalassemia is an inherited hematologic disorder caused by various mutations of the β-globin gene, thus resulting in a significant decrease in adult hemoglobin (HbA) production. An increase in fetal hemoglobin (HbF) levels by drug molecules is considered of great potential in β-thalassemia treatment and is expected to counterbalance the impaired production of HbA. In this work, based on a set of 129 experimentally tested biological inhibitors, we developed and validated a computational model for the prediction of K562 functional inhibition, possibly associated with HbF induction. To facilitate future advancements in the field, we incorporated our model into Enalos Cloud Platform, which enabled online access to our computational scheme (http://enalos.insilicotox.com/K562) through a user-friendly interface. This web service is offered to the wider community to promote in silico drug discovery through fast and reliable predictions.

Molecular Basis of α-Thalassemia in Iran

Alpha-thalassemia (α-thal) is probably the most prevalent monogenic condition in the world. Deletions are the most common types of mutations in α-thal, followed by point mutations and small insertion/deletion. In the context of national screening program for prevention of thalassemia and hemoglobinopathies in Iran, α-thal carriers have come to more attention. Therefore, the frequency and distribution of α-globin mutations in various regions of the country have been studied in recent years. A comprehensive search was performed in PubMed, Scopus, and national databases for finding reports on mutation detection in α-thal carriers and HbH disease with Iranian origin. The mutation data of 10849 α-thal carriers showed that -α^3.7 and α^-5NT were the most common deletional and nondeletional mutations, respectively. In HbH disease cases, the -α^3.7/--^MED was the most prevalent genotype. Overall, 42 different mutations have been identified in α-globin cluster reflecting the high heterogeneity of the mutations in Iranian populations.

An Aγ-globin G->A gene polymorphism associated with β039 thalassemia globin gene and high fetal hemoglobin production

BACKGROUND

Increase of the expression of γ-globin gene and high production of fetal hemoglobin (HbF) in β-thalassemia patients is widely accepted as associated with a milder or even asymptomatic disease. The search for HbF-associated polymorphisms (such as the XmnI, BCL11A and MYB polymorphisms) has recently gained great attention, in order to stratify β-thalassemia patients with respect to expectancy of the first transfusion, need for annual intake of blood, response to HbF inducers (the most studied of which is hydroxyurea).

METHODS

Aγ-globin gene sequencing was performed on genomic DNA isolated from a total of 75 β-thalassemia patients, including 31 β⁰39/β⁰39, 33 β⁰39/β⁺IVSI-110, 9 β⁺IVSI-110/β⁺IVSI-110, one β⁰IVSI-1/β⁺IVSI-6 and one β⁰39/β⁺IVSI-6.

RESULTS

The results show that the rs368698783 polymorphism is present in β-thalassemia patients in the 5'UTR sequence (+25) of the Aγ-globin gene, known to affect the LYAR (human homologue of mouse Ly-1 antibody reactive clone) binding site 5'-GGTTAT-3'. This Aγ(+25 G->A) polymorphism is associated with the Gγ-globin-XmnI polymorphism and both are linked with the β⁰39-globin gene, but not with the β⁺IVSI-110-globin gene. In agreement with the expectation that this mutation alters the LYAR binding activity, we found that the Aγ(+25 G->A) and Gγ-globin-XmnI polymorphisms are associated with high HbF in erythroid precursor cells isolated from β⁰39/β⁰39 thalassemia patients.

CONCLUSIONS

As a potential explanation of our findings, we hypothesize that in β-thalassemia the Gγ-globin-XmnI/Aγ-globin-(G->A) genotype is frequently under genetic linkage with β⁰-thalassemia mutations, but not with the β⁺-thalassemia mutation here studied (i.e. β⁺IVSI-110) and that this genetic combination has been selected within the population of β⁰-thalassemia patients, due to functional association with high HbF. Here we describe the characterization of the rs368698783 (+25 G->A) polymorphism of the Aγ-globin gene associated in β⁰39 thalassemia patients with high HbF in erythroid precursor cells.

Molecular Characterization of β-Thalassemia Intermedia in Southeast Iran

Inheritance of mild mutations within the β-globin gene and coinheritance of α-thalassemia (α-thal) are known as two important genetic modifiers in β-thalassemia (β-thal) intermedia (β-TI). We aimed to evaluate the spectrum of β- and α-thal mutations in β-TI patients in Southeast Iran. Common β- and α-globin gene mutations were detected by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and multiplex gap-PCR, respectively. There were 26 male (57.8%) and 19 female (42.2%) patients. HBB: c.92 + 5T > C [IVS-I-5 (G > C)] and HBB: c.-138C + 1G > A [IVS-II-I (G > A)] represented the prevalent alleles with respective frequencies of 60.0 and 10.0%. Other β-globin mutations included HBB: c.-138C > T [-88 (C > T)], HBB: c.27_28insG [frameshift codons (FSC) 8/9 (+G)], HBB: c.46delT [codon 15 (-T)], HBB: c.93-22_95del (IVS-I, 25 del), and the 619 bp deletion (NG_000007.3: g.71609_72227del619). The predominant genotypic combinations were β(0)/β(0) (68.9%), β(0)/β(+ )(8.9%) and β(+)/β(+ )(2.2%). Coinheritance of α-thal was observed in 33.0% of the patients, with the -α(3.7) (rightward) (NG_000006.1: g.34164_37967del3804) as the most common deletion (86.0%). One patient was diagnosed with the -α(4.2) (leftward) (AF221717) and one with the - -(MED) (g.24664_41064del16401) deletions, while no patients carried the -(α)(20.5) (g.15164_37864del22701), α(-5 nt) (HBA2: c.95 + 2_95_6delTGAGG) or codon 19 (-G) (HBA2: c.56delG) mutations. The alleviating molecular mechanism was not explainable by β(+ )or concurrent α-thal in more than half of our β-TI patients. This encourages conducting more studies to identify other contributing factors, especially Hb F-inducing genetic modifiers.

Current Standards of Care and Long Term Outcomes for Thalassemia and Sickle Cell Disease

Thalassemia and sickle cell disease (SCD) are disorders of hemoglobin that affect millions of people worldwide. The carrier states for these diseases arose as common, balanced polymorphisms during human history because they afforded protection against severe forms of malaria. These complex, multisystem diseases are reviewed here with a focus on current standards of clinical management and recent research findings. The importance of a comprehensive, multidisciplinary and lifelong system of care is also emphasized.

Hb A2 Episkopi - a novel δ-globin chain variant [HBD:c.428C>T] in a family of mixed Cypriot-Lebanese descent

OBJECTIVES

Thalassaemia is a potentially lethal inherited anaemia, caused by reduced or absent synthesis of globin chains. Measurement of the minor adult haemoglobin Hb A₂, combining α- with δ-globin, is critical for the routine diagnosis of carrier status for α- or β-thalassaemia. Here, we aim to characterize a novel δ-globin variant, Hb A₂ Episkopi, in a single family of mixed Lebanese and Cypriot ancestry with mild hypochromic anaemia and otherwise normal globin genotype, which also presents with a coincidental 0.78-Mb sequence duplication on chromosome 1 (1q44) and developmental abnormalities.

METHODS

Analyses included comprehensive haematological analyses, cation-exchange high-performance liquid chromatography (CE-HPLC), cellulose acetate electrophoresis (CAE), Sanger sequencing and structure-based stability predictions for Hb A₂ Episkopi.

RESULTS

The GCT > GTT missense mutation, underlying Hb A₂ Episkopi, HBD:c.428C > T, introduces a cd142 codon change in the mature protein, resulting in reduced normal Hb A₂ amounts and a novel, less abundant Hb A₂ variant (HGVS: HBD:p.A143V), detectable as a delayed peak by CE-HPLC. The latter was in line with structure-based stability predictions, which indicated that the substitution of a marginal, non-helical and non-interface residue, five amino acids from the δ-globin chain carboxy-terminus, was moderately destabilizing.

DISCUSSION

Detection of the new variant depends on the diagnostic set-up and had failed by CAE and on an independent CE-HPLC system, which, in unfavourable circumstances, may lead to misdiagnoses of β-thalassaemia as α-thalassaemia. Given the mixed background of the affected family, the ethnic origin of the mutation is unclear, and this study thus suggests awareness for possible detection of Hb A₂ Episkopi in both the Cypriot and the Lebanese populations.

Structural and Functional Insights on an Uncharacterized Aγ-Globin-Gene Polymorphism Present in Four β0-Thalassemia Families with High Fetal Hemoglobin Levels

INTRODUCTION

Several DNA polymorphisms have been associated with high production of fetal hemoglobin (HbF), although the molecular basis is not completely understood. In order to identify and characterize novel HbF-associated elements, we focused on five probands and their four families (from Egypt, Iraq and Iran) with thalassemia major (either β(0)-IVSII-1 or β(0)-IVSI-1) and unusual HbF elevation (>98 %), congenital or acquired after rejection of bone marrow transplantation, suggesting an anticipated favorable genetic background to high HbF expression.

METHODS

Patient recruitment, genomic DNA sequencing, western blotting, electrophoretic mobility shift assays, surface plasmon resonance (SPR) biospecific interaction analysis, bioinformatics analyses based on docking experiments.

RESULTS

A polymorphism of the Aγ-globin gene is here studied in four families with β(0)-thalassemia (β(0)-IVSII-1 and β(0)-IVSI-1) and expressing unusual high HbF levels, congenital or acquired after rejection of bone marrow transplantation. This (G→A) polymorphism is present at position +25 of the Aγ-globin genes, corresponding to a 5'-UTR region of the Aγ-globin mRNA and, when present, is physically linked in chromosomes 11 of all the familiar members studied to the XmnI polymorphism and to the β(0)-thalassemia mutations. The region corresponding to the +25(G→A) polymorphism of the Aγ-globin gene belongs to a sequence recognized by DNA-binding protein complexes, including LYAR (Ly-1 antibody reactive clone), a zinc-finger transcription factor previously proposed to be involved in down-regulation of the expression of γ-globin genes in erythroid cells.

CONCLUSION

We found a novel polymorphism of the Aγ-globin gene in four families with β(0)-thalassemia and high levels of HbF expression. Additionally, we report evidence suggesting that the Aγ-globin gene +25(G→A) polymorphism decreases the efficiency of the interaction between this sequence and specific DNA binding protein complexes.

A novel compound heterozygosity in Southern China: IVS-II-5 (G > C) and IVS-II-672 (A > C)

β-Thalassemia (β-thal) is a common hereditary anemia due to decreased or absent synthesis of the β-globin chains. Here, we report a patient found to be a novel compound heterozygote for the rare IVS-II-5 (G > C) (NG_000007.3: g.71044G > C) and IVS-II-672 (A > C) (NG_000007.3: g.71711A > C) mutations, which may be silent mutations that are associated with consistent residual output of β chains, normal red blood cell (RBC) indices and normal or borderline Hb A₂ levels.

Rapid detection of pathological mutations and deletions of the haemoglobin beta gene (HBB) by High Resolution Melting (HRM) analysis and Gene Ratio Analysis Copy Enumeration PCR (GRACE-PCR)

OBJECTIVES

Inherited disorders of haemoglobin are the world's most common genetic diseases, resulting in significant morbidity and mortality. The large number of mutations associated with the haemoglobin beta gene (HBB) makes gene scanning by High Resolution Melting (HRM) PCR an attractive diagnostic approach. However, existing HRM-PCR assays are not able to detect all common point mutations and have only a very limited ability to detect larger gene rearrangements. The aim of the current study was to develop a HBB assay, which can be used as a screening test in highly heterogeneous populations, for detection of both point mutations and larger gene rearrangements.

METHODS

The assay is based on a combination of conventional HRM-PCR and a novel Gene Ratio Analysis Copy Enumeration (GRACE) PCR method. HRM-PCR was extensively optimised, which included the use of an unlabelled probe and incorporation of universal bases into primers to prevent interference from common non-pathological polymorphisms. GRACE-PCR was employed to determine HBB gene copy numbers relative to a reference gene using melt curve analysis to detect rearrangements in the HBB gene. The performance of the assay was evaluated by analysing 410 samples.

RESULTS

A total of 44 distinct pathological genotypes were detected. In comparison with reference methods, the assay has a sensitivity of 100 % and a specificity of 98 %.

CONCLUSION

We have developed an assay that detects both point mutations and larger rearrangements of the HBB gene. This assay is quick, sensitive, specific and cost effective making it suitable as an initial screening test that can be used for highly heterogeneous cohorts.

Introduction of novel α1-hemoglobin gene mutation with transfusion-dependent phenotype

OBJECTIVE AND IMPORTANCE

Thalassemia is the most frequently monogenetic disorders around the world that is inherited as a recessive single-gene disease, resulting from mutations in α- or β-globin gene clusters. The aim of this report was to present a new insertional mutation in the α₁ globin gene which causes transfusion-dependent anemia in α-thalassemic patients.

CLINICAL PRESENTATION

Two 5-year-old girls with blood transfusion-dependent α-thalassemia anemia and another girl with moderate α-thalassemia have been presented among patients who have been referred to Hematology and Thalassemia Research Center, Dastgheib Hospital, Shiraz, Iran. They were not relatives. All children were stunted and pale; they were put on regular blood transfusion every 14-21 days.

INTERVENTION

Sequencing of the β-globin gene was normal in all cases and their parents; but, α-globin gene sequencing results were remarkable. An insertion of 21 base pairs (IVS II+3ins (+21nt)(+GACCCGGTCAACTTCAAGGTG) in the α₁-globin gene was detected in all three cases and one of their parents. In two cases, this insertion was accompanied by MED deletion and in one child by POLY A₁ mutation. MED deletion was detected by gap-PCR.

CONCLUSION

This new 21 base pair insertion cannot affect blood parameters on its own, but can present as continuous blood transfusion-dependent α-thalassemia. Thus, it is important to take this point into account for detecting the carriers, like β-thalassemia carriers, which can present as transfusion-dependent children in parents with α-thalassemia trait.

Pregnancy in women with thalassemia: challenges and solutions

Advances in treatment of thalassemia have led to the aging of thalassemic patients, and consequently concern about successful reproductive outcome is augmented. Although women with thalassemia intermedia only were considered competent of achieving pregnancy, case series reveal the willingness of both thalassemia major and thalassemia intermedia women to have a family. Pregnancy in general is characterized by dynamic multiple-system changes and increased susceptibility to oxidative stress, while homozygous, transfusion-dependent, β-thalassemia patients manifest cardiac, hepatic, endocrine, and metabolic disorders attributable to chronic anoxia and iron overload and thalassemia intermedia, usually nontransfused, is associated with augmented risk of thromboembolic events. Pregnancy in thalassemia should be considered a high risk for both mother and fetus, and favorable outcomes are the result of continuous preconception, antenatal, and postpartum assessment and management by a team of thalassemia experts.

The molecular characterization of Beta globin gene in thalassemia patients reveals rare and a novel mutations in Pakistani population

INTRODUCTION

A multicentre study (including four cities in Pakistan) aimed to investigate the frequency and spectrum of alpha and beta thalassemia genetic mutations and XmnI polymorphism of the Gamma Globin gene.

METHODS

One hundred and sixty one beta thalassemia patients, identified on the ground of haematological parameters, were screened for mutations of the Alpha (HBA2 and HBA1) and Beta (HBB) Globin genes as well as Gamma (HBG2) Globin gene, -158 Gγ XmnI polymorphism, using a combination of multiplex GAP polymerase chain reaction (PCR), Sanger sequencing and restriction fragment length polymerase (RFLP) based PCR.

RESULTS

Mutations of at least one HBB gene was identified in 157 of 161 patients screened. Among 16 identified mutations in the beta gene, HBB:c.27_28insG (p. Ser10Valfs*14) was the most prevalent. α(-3.7) and α(-4.2) deletions were co-inherited with beta thalassemia mutations. Rare mutations such as HBB:c.-138C > T and HBB:c.315 + 1G > A were also identified. One novel variant (HBB:c.-148T > A), two rare mutations [HBB:c.332T > C (p.Leu111Pro); HBB:c.92G > C (p.Arg31Thr] and a novel association, HBB:c.[92G > C (p.Arg31Thr)] and [-92C > G], were reported for the first time in our study. HBG2:c.-211C > T base-pair substitution (historically described as -158 GγXmnI polymorphism) was present in 36% of the patients.

CONCLUSION

Heterogeneity in clinical and haematological parameters in TM, show that monogenic disorders can present with a wide spectrum of disease severity. Our studies identified rare and novel mutations that will be useful in the prevention of highly prevalent disease of thalassemia in Pakistan following nationwide awareness campaign.

A Simple, Rapid, and Highly Sensitive Electrochemical DNA Sensor for the Detection of α- and β-Thalassemia in China

BACKGROUND

Because of the life-consuming treatment and severe consequences associated with thalassemia, it is more effective to prevent than cure thalassemia. Rapid and sensitive detection is critical for controlling thalassemia. In this study, we developed a rapid and accurate test to genotype nondeletional α- and β-thalassemia mutations by an electrochemical DNA sensor.

METHODS

Screen-printed electrodes were used as electrochemical transducers for the sensor, in which the capture probe DNA was attached to the golden surface of the working electrode via an S-Au covalent bond, which is highly suitable for immobilizing the biological element. In addition, two types of ferrocene with varying redox potentials for modified signal probe DNA were adopted. The hybridization signal is detected by alternating current voltammetry when the capture probe and signal probe hybridize with the target DNA.

RESULTS

With this technique, 12 types of nondeletional α- and β-thalassemia mutations were detected, which constitute more than 90% of all the nondeletional types of thalassemia mutation determinants found in China, including the CD142 (TAA>CAA) Constand spring, CD125 (CTG>CCG) Quonsze, CD122 (CAC>CAG) Weastmead, -28 (A>G), Cap+1 (A>C), initiation codon (ATG>AGG), CD17 (AAG>TAG), CD26 (GAG>AAG), CD31(-C), CD41-42 (-CTTT), CD71-72 (+A), and IVS-II-654 (C>T) mutations. Concordance levels were 100% within the 20 blood samples of homozygous wild-type individuals and 238 blood samples of heterozygous mutant individuals.

CONCLUSIONS

The electrochemical DNA sensor developed here can be applied for rapid genotyping of thalassemia or other clinical genotyping applications and is useful for early screening of thalassemia in high-risk groups by minimizing the time and investment cost.

Investigation of molecular heterogeneity of β-thalassemia disorder in District Charsadda of Pakistan

Objective:

Thalassemia is blood related disease which arises from the reduced level of hemoglobin in red blood cells (RBC), a protein responsible for carrying oxygen inside the body. Considering its widespread occurrence in developing countries like Pakistan, this study aims to investigate the common molecular anomalies of the beta thalassemia disease in district Charsadda, Khyber Pakhtunkhwa.

Methods:

This work was done at Abdul Wali Khan University (AWKU) Mardan, Khyber Pakhtunkhwa, Pakistan. The work was performed on the blood samples collected from the patients and their families with beta thalassemia major (n = 13 families) belonged to District Charsadda. The collected blood samples were analyzed for presence of six known mutations with the help of polymerase cha in reaction technique i.e. amplification of refractory mutation system.

Results:

Our Study reports six known mutations (IVS-1-5, FSC 8/9, CD 41/42, IVS-1-1, CD 15 and FSC-5) accounting for about 90% of total beta thalassemia genes in this country. Among the reported mutations, IVS 1-5 was the most prevalent beta thalassemia gene in patients belonging to District Charsadda.

Conclusion:

The results and findings of the current study may help in accessing the frequency of these common mutations and in initiating pre-natal diagnosis programme in Pakistan.

Does thalassemia influence ovarian response? An analysis of 127 cycles involving pre-implantation genetic diagnosis of thalassemia in southern China

To evaluate the impact of thalassemia carrier status on the response to controlled ovarian stimulation (COS) and outcome of intracytoplasmic sperm injection (ICSI). Seventy couples that both carried a mutation attributed to thalassemia (PGD group) and 57 couples in which only the father was a thalassemia carrier (CON group) were enrolled. All female subjects received long protocol GnRH agonist stimulation and received equivalent doses of recombinant follicle-stimulating hormone and the number of retrieved oocytes and utilisable embryos did not differ significantly. The endometrial thickness at human chorionic gonadotropin (hCG) administration day and the number of transferable embryos was lower in the PGD groups. However, pregnancy outcomes, including the clinical pregnancy rate and ongoing pregnancy rate, did not differ significantly between the two groups per cycle. Ovarian response to COS is not impaired by maternal thalassemia carrier status and embryo biopsy did not impair preimplantation embryo development or pregnancy outcomes.

Expanded newborn screening by mass spectrometry: New tests, future perspectives

Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs.

Development and characterization of K562 cell clones expressing BCL11A-XL: Decreased hemoglobin production with fetal hemoglobin inducers and its rescue with mithramycin

Induction of fetal hemoglobin (HbF) is considered a promising strategy in the treatment of β-thalassemia, in which production of adult hemoglobin (HbA) is impaired by mutations affecting the β-globin gene. Recent results indicate that B-cell lymphoma/leukemia 11A (BCL11A) is a major repressor of γ-globin gene expression. Therefore, disrupting the binding of the BCL11A transcriptional repressor complex to the γ-globin gene promoter provides a novel approach for inducing expression of the γ-globin genes. To develop a cellular screening system for the identification of BCL11A inhibitors, we produced K562 cell clones with integrated copies of a BCL11A-XL expressing vector. We characterized 12 K562 clones expressing different levels of BCL11A-XL and found that a clear inverse relationship does exist between the levels of BCL11A-XL and the extent of hemoglobinization induced by a panel of HbF inducers. Using mithramycin as an inducer, we found that this molecule was the only HbF inducer efficient in rescuing the ability to differentiate along the erythroid program, even in K562 cell clones expressing high levels of BCL11A-XL, suggesting that BCL11A-XL activity is counteracted by mithramycin.

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K562 clones were described with integrated copies of a BCL11A-XL expressing vector.

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B-Cell lymphoma/leukemia 11A-XL (BCL11A-XL) levels inversely correlate with the extent of hemoglobin induction.

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Mithramycin induces γ-globin genes even in K562 clones expressing high levels of BCL11A-XL.

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K562(BCL11A-XL) clones might be useful in identifying fetal hemoglobin inducers acting on BCL11A.

Screening for common β-globin gene cluster deletions in Chinese individuals with increased hemoglobin F

INTRODUCTION

The aim of this study was to determine the prevalence of β-globin gene cluster deletions in individuals with increased Hb F levels in a Chinese population.

METHODS

Subjects with HbF levels ≥ 10% were selected for further investigation. Gap-PCR was used to screen for three common β-globin gene cluster deletions: Chinese ((A) γδβ)(0)-thalassemia, Southeast Asian (SEA) deletion and Hb Lepore. Multiplex ligation-dependent probe amplification (MLPA) was used to analyze dosage changes of the β-globin gene cluster for those not associated with one of the three common deletions.

RESULTS

One hundred and thirty-one individuals had an increased Hb F level; among these, 51 (38.9%) were showed to have Chinese ((A) γδβ)(0)-thalassemia (n = 37) or SEA deletion (n = 14). A single case of Hb Lepore-Boston-Washington was detected. MLPA only detected 2 deletions in three cases of the remaining 80 patients. Gap-PCR confirmed that they included a 1357 bp β-globin gene deletion (NG_000007.3:g.69997_71353del1357) in one case and a HBG2-HBG1 fusion gene consisting of exons 1 and 2 of HBG2 ((G) γ-globin gene) and exon 3 of HBG1 ((A)γ-globin gene) (HBG2:c.315 + 573_HBG1: c.315 + 572del) in two cases.

CONCLUSION

The Chinese ((A) γδβ)(0)-thalassemia and SEA deletion are the most common large deletions of β-globin gene cluster in Chinese. Gap-PCR for the detection of these two deletions should be used in thalassemia screening program in China where the incidence of β-thalassemia is high.

Low and fixed dose of hydroxyurea is effective and safe in patients with HbSβ(+) thalassemia with IVS1-5(G→C) mutation

BACKGROUND

Despite compelling evidence that hydroxyurea is safe and effective in sickle cell disease, it is prescribed sparingly due to several barriers like knowledge gaps in certain genotypes, apprehension about its safety and toxicity, and limited resources. We undertook this study to find out the efficacy and safety of HU in patients with HbSβ(+) -thalassemia with IVS1-5(G→C) mutation.

PROCEDURE

We registered 318 patients with HbSβ(+) -thalassemia with IVS1-5(G→C) mutation. Of these, 203 were enrolled for hydroxyurea treatment at a low and fixed dose of 10 mg/kg/day. One hundred four patients (Group-I: 37 children and Group-II: 67 adults) with ≥2 years of hydroxyurea treatment were studied.

RESULTS

The rate of vaso-occlusive crises, requirement of blood transfusion and rate of hospitalization reduced from 3 to 0.5, 1 to 0 and 1 to 0 in Group-I and 3 to 0, 1 to 0 and 0.5 to 0 in Group-II respectively after HU therapy (P < 0.0001). %HbF level, hemoglobin, MCV and MCH increased significantly, whereas HbS, WBC, platelet count, serum-bilirubin and LDH levels decreased significantly after HU therapy. It has been observed that along with fairly subtle hematological changes following HU therapy, there was a substantial clinical improvement occurred in these patients. Transient myelotoxicity was observed in 4.8%. There was minimal gonadal toxicity without affecting reproductive function.

CONCLUSION

In view of easy affordability, better acceptability, minimal toxicity, the need of infrequent monitoring and its potential effectiveness, low and fixed dose of hydroxyurea is suitable for treatment of patients with HbSβ(+) -thalassemia in resource poor setting.

Generation and Characterization of a Transgenic Mouse Carrying a Functional Human β -Globin Gene with the IVSI-6 Thalassemia Mutation

Mouse models that carry mutations causing thalassemia represent a suitable tool to test in vivo new mutation-specific therapeutic approaches. Transgenic mice carrying the β-globin IVSI-6 mutation (the most frequent in Middle-Eastern regions and recurrent in Italy and Greece) are, at present, not available. We report the production and characterization of a transgenic mouse line (TG-β-IVSI-6) carrying the IVSI-6 thalassemia point mutation within the human β-globin gene. In the TG-β-IVSI-6 mouse (a) the transgenic integration region is located in mouse chromosome 7; (b) the expression of the transgene is tissue specific; (c) as expected, normally spliced human β-globin mRNA is produced, giving rise to β-globin production and formation of a human-mouse tetrameric chimeric hemoglobin ^muα-globin₂/^huβ-globin₂ and, more importantly, (d) the aberrant β-globin-IVSI-6 RNAs are present in blood cells. The TG-β-IVSI-6 mouse reproduces the molecular features of IVSI-6 β-thalassemia and might be used as an in vivo model to characterize the effects of antisense oligodeoxynucleotides targeting the cryptic sites responsible for the generation of aberrantly spliced β-globin RNA sequences, caused by the IVSI-6 mutation. These experiments are expected to be crucial for the development of a personalized therapy for β-thalassemia.

Recent trends in the gene therapy of β-thalassemia

The β-thalassemias are a group of hereditary hematological diseases caused by over 300 mutations of the adult β-globin gene. Together with sickle cell anemia, thalassemia syndromes are among the most impactful diseases in developing countries, in which the lack of genetic counseling and prenatal diagnosis have contributed to the maintenance of a very high frequency of these genetic diseases in the population. Gene therapy for β-thalassemia has recently seen steadily accelerating progress and has reached a crossroads in its development. Presently, data from past and ongoing clinical trials guide the design of further clinical and preclinical studies based on gene augmentation, while fundamental insights into globin switching and new technology developments have inspired the investigation of novel gene-therapy approaches. Moreover, human erythropoietic stem cells from β-thalassemia patients have been the cellular targets of choice to date whereas future gene-therapy studies might increasingly draw on induced pluripotent stem cells. Herein, we summarize the most significant developments in β-thalassemia gene therapy over the last decade, with a strong emphasis on the most recent findings, for β-thalassemia model systems; for β-, γ-, and anti-sickling β-globin gene addition and combinatorial approaches including the latest results of clinical trials; and for novel approaches, such as transgene-mediated activation of γ-globin and genome editing using designer nucleases.

Coinheritance of Hb D-Punjab and β-thalassemia: diagnosis and implications in prenatal diagnosis

Hb D-Punjab (HBB: c.364G>C) is an abnormal hemoglobin (Hb) associated with genetic risk in association with Hb S (HBB: c.20A>T). In addition, misdiagnosing homozygosis for hemizygosis may have implication for genetic risk assessment. We present the diagnostic utility of high performance liquid chromatography (HPLC) in differential diagnosis between the Hb D-Punjab homozygote and the Hb D-Punjab/β-thalassemia (β-thal) genotype. The Hb A2 level measurement may not be a reliable parameter to differentiate between the two conditions. In a screening program for risk prediction, the genotype should be confirmed by family study and/or molecular analysis. Misdiagnosis can have potentially adverse implications in a prenatal diagnosis (PND) program, particularly in areas where consanguinity is common and this Hb D-Punjab variant occurs.

The effect of hydroxyurea on compound heterozygotes for sickle cell-hemoglobin D-Punjab--a single centre experience in eastern India

BACKGROUND

Although hydroxyurea is the only effective agent for the treatment of sickle cell disease, published experience with this drug is limited to treatment of homozygous sickle cell anemia and HbS/β thalassemia. The role of hydroxyurea in the treatment of patients with HbSD-Punjab, a rare hemoglobinopathy with phenotypic expression similar to that of sickle cell anemia is unknown.

PROCEDURE

Over a period of 10 years, we followed 42 patients with HbSD-Punjab, of which 20 presented with severe clinical manifestations (≥3 episodes of VOC and/or ≥2 units of blood transfusion in the previous 12 months). These 20 patients were enrolled for treatment with hydroxyurea at a dose of 10 mg/kg/day and followed prospectively for a period of 24 months.

RESULTS

The frequency of VOC decreased significantly and none of them required blood transfusion while receiving hydroxyurea. The HbF, total hemoglobin, MCV, MCH, and MCHC levels increased significantly, whereas HbS, WBC, platelet count, total serum bilirubin, and LDH levels decreased significantly in all the patients. No short-term drug toxicity was observed.

CONCLUSION

This study describes the use of hydroxyurea therapy in patients with HbSD-Punjab. Low dose hydroxyurea (10 mg/kg/day) was found to be effective in reducing the clinical severity in patients with HbSD-Punjab without any short-term toxicity. In view of easy affordability amongst poor patients, widespread acceptability by patients and doctors, the need of infrequent monitoring and its potential effectiveness, low dose hydroxyurea is suitable for treatment of patients with HbSD-Punjab.

Impact of β-globin mutations on outcome of matched related donor hematopoietic stem cell transplantation for patients with β-thalassemia major

The clinical outcome of hematopoietic stem cell transplantation (HSCT) for patients with β-thalassemia major (β-TM) can be affected by several factors. We investigated the influence of β-globin gene mutation in patients with β-TM on the clinical outcome of HSCT and conducted a prospective study of consecutive β-TM patients who underwent allogeneic HSCT at our center. Among 87 included patients, 62 (71%) had homozygous and 25 (29%) had compound heterozygous β-globin gene mutations. Intervening sequence II-1 appeared to be the most common mutation, with an occurrence rate of 33% in β-globin alleles. With a median follow-up of 12 months, the thalassemia-free survival and overall survival probabilities were 83% (standard error, 4%) and 90% (standard error, 3%), respectively. Overall survival was not found to be associated with the β-globin gene mutation status, but thalassemia-free survival was significantly improved in patients with homozygous mutations compared with patients with compound heterozygous mutations in univariate (91.2% versus 64.0%, P = .009) and multivariable (hazard ratio, 3.83; P = .014) analyses. This is the first report on the impact of β-globin mutation status on the outcome of β-TM after allogeneic HSCT and helps to better illustrate the course and prognosis of β-TM after transplantation.

Recent trends for novel options in experimental biological therapy of β-thalassemia

INTRODUCTION

β-thalassemias are caused by nearly 300 mutations of the β-globin gene, leading to low or absent production of adult hemoglobin. Achievements have been recently obtained on innovative therapeutic strategies for β-thalassemias, based on studies focusing on the transcriptional regulation of the γ-globin genes, epigenetic mechanisms governing erythroid differentiation, gene therapy and genetic correction of the mutations.

AREAS COVERED

The objective of this review is to describe recently published approaches (the review covers the years 2011 - 2014) useful for the development of novel therapeutic strategies for the treatment of β-thalassemia.

EXPERT OPINION

Modification of β-globin gene expression in β-thalassemia cells was achieved by gene therapy (eventually in combination with induction of fetal hemoglobin [HbF]) and correction of the mutated β-globin gene. Based on recent areas of progress in understanding the control of γ-globin gene expression, novel strategies for inducing HbF have been proposed. Furthermore, the identification of microRNAs involved in erythroid differentiation and HbF production opens novel options for developing therapeutic approaches for β-thalassemia and sickle-cell anemia.

Alpha-thalassemia mutations in adana province, southern Turkey: genotype-phenotype correlation

To look over the distribution of the mutations in a large series from Adana province, Southern Turkey, and determine the genotype-phenotype correlation of the frequent mutations. Among the 2500 individuals with mild or moderate anemia, microcytosis, and normal iron levels that were referred to our Genetic Diagnosis Center, a population consisting of 539 individuals were included in the study and tested for alpha-thalassemia mutations by using reverse dot blot hybridization technique. Twelve different mutations were detected in 539 patients. Among the 12 different mutations found, the most frequent mutations were the -α(3.7) (63.3 %), --(MED) (11.7 %), --(20.5) (10.7 %), α2(IVS1(-5nt)) (3.9 %), and α2(polyA-2) (3.5 %). The most frequent genotypes were -α(3.7)/αα (35.8 %), -α(3.7)/-α(3.7)(18.9 %), -(20.5)/αα (11.5 %), and --(MED)/αα (10.4 %), respectively. There were statistically significant differences in hematological findings between -α(3.7)/-α(3.7) and --(MED)/αα, even though both have two mutated genes in the genotype. Our results show that alpha-thalassemia mutations are highly heterogeneous as well as deletional and -α(3.7) single gene deletion is particularly prevalent at Adana province in agreement to other studies from Turkey.

Sensitivity and specificity of single-tube osmotic fragility test and its different methods as screening test for thalassemia trait: an alternative to expensive laboratory tests for resource-limited countries

OBJECTIVE

To determine the sensitivity and specificity of single-tube osmotic fragility (SOFT) and its different methods as screening test for thalassemia trait.

METHODS

A cross-sectional study was conducted at Omair Sana Foundation. A total of 400 participants were included in the study. Three hundred were known thalassemia carriers (parents with at least one child with thalassemia major), while 100 were healthy blood donors. SOFT was performed on all 400 participants. Serum iron, ferritin, and DNA tests were performed on 100 participants (donors). ARMS technique was used for detecting thalassemia mutations.

RESULTS

Sensitivity and specificity of SOFT (venous method) were found to be 99.6% and 86%, respectively, while with EDTA method, sensitivity was 95% and specificity was 96%. For venous and EDTA methods, positive predictive values were 95.5% and 98.6%, respectively, while negative predictive values were 98.8% and 86.6%, respectively. Use of EDTA and storage had an effect on the results. Sensitivity of SOFT was 95% at 5 min, while it decreased to 87% with EDTA method at 240 min. Sensitivity of SOFT for iron deficiency anemia was found to be 14%.

CONCLUSION

SOFT can be used as screening test for thalassemia trait in a cost-effective way. Moreover, we also found that SOFT should be performed on venous blood without adding preservatives (EDTA) that can interfere with the results.

Evaluation of high performance liquid chromatography (HPLC) pattern and prevalence of beta-thalassaemia trait among sickle cell disease patients in Lagos, Nigeria

Introduction

Sickle cell disease (SCD) is the most common inherited disorder of haemoglobin worldwide. This study evaluated the chromatographic patterns and red blood cell indices of sickle cell patients to determine the co-inheritance of other haemoglobin(Hb) variants and β-thalassaemia trait.

Methods

Red cell indices, blood film, sickle solubility test, Hb electrophoresis using alkaline cellulose acetate membrane, and chromatographic patterns using Bio Rad HPLC Variant II were evaluated for 180 subjects.

Results

Based on low MCV <76fL and MCH<25 pg, in the presence of elevated A₂ >4.0% on HPLC and Hb variants eluting outside the S and C windows, at least four haemoglobin phenotypes (SS: 87.7%; SC: 1.1%; SD Punjab: 0.6%; Sβ-thalassemia: 10.6%) were identified. Mean Hb F% was 8.1±5.1 (median 7.65) for Hb SS and 6.03±5.2 (median 3.9) for Hb Sβ-thalassemia trait. Majority of Hb SS (69.1%) had Hb F% less than 10 while 27.6% had 10-19.9 and 3.2% had ≥ 20. Mean Hb F% was higher in female Hb SS (9.55±5.09; mean age 7.4±3.8 years) than the males (7.63±4.80; mean age 6.9±3.8 years) (P=0.02). A borderline significant negative correlation between age and Hb F levels among Hb SS subjects (r= -0.169 P=0.038) was also observed.

Conclusion

Our data suggests that α and β- thalassaemia traits, and other haemoglobin variants co-exist frequently with SCD in our population

Prevalence of deletional alpha thalassemia and sickle gene in a tribal dominated malaria endemic area of eastern India

Inherited hemoglobin disorders like alpha thalassemia and sickle gene are common in the Indian subcontinent. These disorders in the heterozygous state act as malaria resistance genes and influence the susceptibility to Plasmodium falciparum malaria. There is inadequate knowledge about the epidemiology of these malaria resistance genes in the tribal dominated malaria endemic region of the state of Odisha in eastern India. A cross sectional prevalence study was undertaken in 594 subjects in five tribal populations in this region, namely, Sahara (42.4%), Kutia Kandha (30.0%), Kuda (15.8%), Gond (9.8%), and Oraon (2.0%). Sickling test, Hb electrophoresis, HPLC, and molecular studies were undertaken to diagnose the prevalence of sickle allele, β-thalassemia allele, and deletional alpha thalassemia. Sickle and β thalassemia alleles were found in 13.1% and 3.4% of subjects, respectively. Sickle allele was found both in heterozygous (10.1%) and homozygous state (3.03%). The prevalence of alpha thalassemia was 50.84% with an allelic frequency of 0.37. Both α^−3.7 and α^−4.2 alpha thalassemia were detected with an allele frequency of 0.33 and 0.04, respectively. The high prevalence of alpha thalassemia and sickle gene in this population is probably due to selection pressure of endemic malaria in this part of India.