A More Universal Approach to Comprehensive Analysis of Thalassemia Alleles (CATSA)

The aim of the study was to assess the clinical utility of a third-generation sequencing (TGS) approach termed comprehensive analysis of thalassemia alleles (CATSA) for identifying both α and β thalassemia genetic carrier status. Prospective blood samples (n = 1759) with abnormal hemoglobin parameters were screened for pathogenic thalassemia variants by CATSA on the PacBio TGS platform. In 1159 individuals, a total of 1317 pathogenic thalassemia variants were identified and confirmed by independent PCR-based tests. Of the total thalassemia variants detected, the α-variant --^SEA (35.4%) and β-variant c.126_129delCTTT (15%) were the most common. CATSA was also able to detect three types of rare HBA structural variants as well as five rare HBA2, three HBA1, and 10 HBB single-nucleotide variations/insertions and deletions. Compared with standard thalassemia variant PCR panel testing, CATSA identified all panel variants present, with no false-negative results. Carrier assignment was improved through identification of rare variants missed by the panel test. On the basis of allelic coverage, reliability, and accuracy, TGS with long-range PCR presents a comprehensive approach with the potential to provide a universal solution for thalassemia genetic carrier screening. It is proposed that CATSA has immediate clinical utility as an effective carrier screening approach for at-risk couples.

Prevalence and Utility of Low Mean Corpuscular Volume in Infants Admitted to the Neonatal Intensive Care Unit

OBJECTIVE

To determine the prevalence of low mean corpuscular volume (MCV) in newborn infants admitted to the neonatal intensive care unit and to assess low MCV as a diagnostic test for alpha thalassemia.

STUDY DESIGN

Retrospective analysis of all infants admitted to the neonatal intensive care unit between January 2010 and October 2018 for which a complete blood count was performed during the first 3 postnatal days. Infants with a low MCV were compared with those with a normal MCV. Infants with positive hemoglobin Bart (Hb Bart) were compared with those withnegative Hb Bart. Low MCV was also evaluated as a diagnostic test for alpha thalassemia.

RESULTS

A total of 3851 infants (1386 preterm, 2465 term) met the inclusion criteria and 853 (22.2%) had a low MCV. A low MCV was more common in term (25%) compared with preterm infants (17.1%, P < .001). Hb Bart positive newborn screening was identified in 133 infants (3.5%). Hb Bart was positive in 11.1% of infants with low MCV compared with 1.3% with normal MCV (P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value of low MCV for the diagnosis of alpha thalassemia were 71.4%, 79.6%, 11.3%, and 98.7%, respectively.

CONCLUSIONS

As Hb Bart positive newborn screens were seen in only 11.1% of infants with microcytosis, further diagnostic investigation may be warranted in individual infants. Further research to correlate microcytosis with iron status in infants and mothers is needed as well as studies using DNA analysis for the evaluation of alpha thalassemia variants.

A Nested Asymmetric PCR Melting Curve Assay for One-Step Genotyping of Nondeletional α-Thalassemia Mutations

A rapid DNA-based assay is essential for clinical diagnosis and mass screening in thalassemia-prevention programs. Because of high homology and guanine-cytosine-rich and complex second structure of α-globin genes, it is rather difficult to develop a feasible and simple method for α-thalassemia genotyping. In this study, a strategy of nested asymmetric PCR melting curve analysis was designed to tackle these factors and ensure sensitivity and accuracy. Herein, a novel one-step assay for genotyping of nondeletional α-thalassemia mutations, including hemoglobin (Hb) Westmead (HBA2: c.369C>G), Hb Quong Sze (HBA2: c.377T>C), Hb Constant Spring (HBA2: c.427T>C), CD30 (HBA2: c.91-93delGAG), and CD31 (HBA2: c.95G>A) in a single closed tube, was established and evaluated. All five mutations were accurately determined with the concordance rate of 100% in a blind analysis of 255 genotype-known samples and 1250 clinical samples. In conclusion, this assay is useful for rapid and reliable genotyping of nondeletional α-thalassemia mutations in clinical practice. Especially, the strategy may have the potential to be a versatile scheme for rapid genotyping of other gene mutations because of its high throughput, sufficient stability, low cost, and simple operation.

Impact of the detection of ζ-globin chains and hemoglobin Bart's using immunochromatographic strip tests for α0-thalassemia (--SEA) differential diagnosis

α⁰-Thalassemia is an inherited hematological disorder caused by the deletion of α-globin genes. The Southeast Asian deletion (--^SEA) is the most common type of α⁰-thalassemia observed in Southeast Asian countries. Regarding WHO health policy, an effective α⁰-thalassemia screening strategy is needed to control new severe α-thalassemia cases. In this study, a monoclonal antibody panel was used to develop immunochromatographic (IC) strip tests for detecting the Hb Bart’s and ζ-globin chain. Among 195 samples, all α⁰-thalassemia traits (78 α⁰-thalassemia (--^SEA) and 4 α⁰-thalassemia (--^THAI)) had low MCV or MCH values. The sensitivity, specificity, PPV and NPV of the IC strip tests for ζ-globin and Hb Bart’s for screening α⁰-thalassemia (--^SEA) within the low MCV or MCH samples were 100%, 65.2%, 90.7%, 100% and 96.2%, 47.8%, 86.6%, 78.6%, respectively. All 4 α⁰-thalassemia (--^THAI) traits were negative for ζ-globin chains but positive for Hb Bart’s using the IC strip tests. These results led to a α⁰-thalassemia screening being proposed in which blood samples are first evaluated by MCV, MCH and Hb typing. Samples with high MCV and MCH values are excluded for the presence of the α⁰-thalassemia gene. Samples with low MCV or MCH values are assayed using the developed IC strip tests, where only samples testing positive are further assayed for α⁰-thalassemia by PCR. Patients with Hb H, EA Bart’s or EF Bart’s diseases do not need to use this IC strip assay. Thus, in this study, a simple and cost effective α⁰-thalassemia point of care test was developed.

Hydroxyurea alters hematological, biochemical and inflammatory biomarkers in Brazilian children with SCA: Investigating associations with βS haplotype and α-thalassemia

This study investigated the effects of hydroxyurea (HU) on hematological, biochemical and inflammatory parameters in children with sickle cell anemia (SCA) in association with βS haplotype and α-thalassemia. We included 22 children with SCA who were followed for an average of 14.5 months. Laboratory parameters were assessed by electronic methods, and molecular analysis was investigated by PCR-RFLP and allele-specific PCR. Results showed significant increases in hemoglobin, HbF, hematocrit, MCV, MCH, glucose, HDL-C and albumin levels, as well as significant decreases in MCHC and AST levels, WBC, neutrophils, eosinophils, lymphocytes and reticulocytes, in children during HU therapy. HbF levels were positively correlated with hemoglobin, hematocrit, MCV and total protein, yet negatively correlated with MCHC, RDW, AAT and AST during HU therapy (p<0.05). Children who carried the Central African Republic haplotype, in response to HU therapy, presented significant increases in hemoglobin, hematocrit, triglycerides and uric acid levels, as well as significant decreases in MCHC, AST and direct bilirubin levels, WBC, neutrophils, eosinophils, lymphocytes and reticulocytes. Those with the Benin haplotype presented increases in HbF and albumin levels, and a reduction in platelet counts (p<0.05). Children with α-thalassemia presented decreased ALT during HU use, while those without this deletion presented increases in hemoglobin, hematocrit, MCV, MCH, HDL-C and albumin, as well as decreases in MCHC, neutrophils, lymphocytes, reticulocytes and AST (p<0.05). Hence, regardless of its use in association with βS haplotypes or α-thalassemia, HU seems to be linked to alterations in hemolytic, inflammatory, hepatic, lipid and glycemic profiles.

Frequency of Alpha Thalassaemia in homozygous Beta Thalassaemia paediatric patients and its clinical impact at a blood disease centre in Karachi, Pakistan

OBJECTIVE

To find frequency ofalpha Thalsaemia nhomozygous beta Thalsaemia patients, and to se any difernce infrequency and age ofirst ransfusion and mean haemoglobin concentration.

METHODS

The single-centred, escriptive cros-sectional study was conducted athe National Instiute of Blod Disease and Bone Marow Transplantaion, Karchi, from June 1,2012, to May 31, 2013. Patients of homozygous beta halsaemia, diagnosed by polymerase chain reaction, wer tested for coinheritance of alpha Thalsaemia nd foetal haemoglobin XMN1 polymorphism using polymerase chain reaction. SPS 17 was used for dat anlysi.

RESULTS

Of the 286 patients, 19(41.6%) wer males, and 9(34.6%) showed coinheritance ofalpha thalsaemia. In the coinheritance group, 50(50%) and 1(1%) patients recived 1-20 and 21-40 times transfusions per year espectively, while inthe non-coinheritance group, the coresponding numbers wer 125(67%) and 27(14.%). Overal, 73(25.%) patients had nevr ben transfused, including 38(13.%) patients inthe alpha Thalsaemia group. XMN1 polymorphism was found in 86(41%) ofthe 208 patients who wer tested and anlysed on this count.

CONCLUSIONS

Alpha thalsemia was presnt inmore than one-third homozygous beta halsemia patients.

Evaluation of Thalassaemia Screening Tests in the Antenatal and Non-Antenatal Populations in Singapore

INTRODUCTION

Haemoglobinopathy testing is performed for carrier screening and evaluation of microcytic anaemia. We evaluated the effectiveness of thalassaemia screening tests at our institution and suggest ways of improving the testing algorithm.

MATERIALS AND METHODS

A total of 10,084 non-antenatal and 11,364 antenatal samples with alkaline gel electrophoresis (AGE), capillary electrophoresis (CE), haemoglobin H (HbH) inclusion test, mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) were retrospectively reviewed. A subgroup of 187 samples with genetic testing was correlated with HbH inclusions and MCH/ MCV. The effect of iron deficiency on percentage hemoglobin A2 (HbA2) was studied.

RESULTS

HbH inclusion test showed low sensitivity of 21.43% for α-thalassaemia mutations but higher sensitivity of 78.95% for ^--SEA deletion. By receiver operating characteristic (ROC) analysis, MCH ≤28 pg or MCV ≤80 fl for non-antenatal samples and MCH ≤27 pg or MCV ≤81 fl for antenatal samples had >98% sensitivity for HbH inclusions. Above these thresholds, the probability that HbH inclusions would be absent was <99% (negative predictive value [NPV] >99%). MCH ≥28 pg had 100% sensitivity (95% CI 95.63%-100%) for α-thalassaemia mutations and 97.68% calculated NPV in the antenatal population. Detection of haemoglobin variants by CE correlated highly with AGE (99.89% sensitivity, 100% specificity). Severe iron deficiency reduced HbA2 in hemoglobin (P <0.001) and α-thalassaemia (P = 0.0035), but not in β-thalassaemia.

CONCLUSION

MCH/MCV thresholds have adequate sensitivity for α-thalassaemia in the antenatal population, and genotyping plays an important role as HbH inclusion test shows low sensitivity. CE without AGE, may be used as initial screening for haemoglobin variants. Our study provides contemporary data to guide thalassaemia screening algorithms in Singapore.

Rheological properties of sickle erythrocytes in patients with sickle-cell anemia: The effect of hydroxyurea, fetal hemoglobin, and α-thalassemia

OBJECTIVE

Determine the effect of fetal hemoglobin (HbF) and α-thalassemia on red blood cell (RBC) deformability of patients with sickle-cell anemia (SCA) with and without hydroxyurea (HU).

METHODS

Adult patients were enrolled in the Sickle Cell Program of the Cardeza Foundation (Thomas Jefferson University) and were followed up prospectively during the period in which the Multicenter Study of Hydroxyurea (MSH) in patients with SCA was conducted. Ninety-one patients did not receive HU, 20 patients were enrolled in MSH, and 10 patients were enrolled in an open-label study of HU in SCA. Of the 20 patients enrolled in MSH, 11 took HU and nine took placebo. Control group included 113 normal individuals. Red blood cell deformability index (DI) was measured by ektacytometry.

RESULTS

Patients with SCA taking HU (n = 21) had higher DI than those taking placebo (n = 9) or who were not taking this therapy (n = 91). In patients without therapy, those with α-thalassemia (n = 31) had higher DI than those without. We showed a significant positive correlation between the level of HbF and DI. SCA patients without α-thalassemia and HbF <10% (n = 48) had lower DI than patients with α-thalassemia and HbF <10% (n = 23) and patients with (n = 8) or without α-thalassemia but with HbF >10% (n = 12). DI measured in patients without α-thalassemia and HbF >10% was higher than in the three other subgroups.

CONCLUSION

Elevated levels of HbF with or without HU and α-thalassemia improve sickle RBC rheology, which, in turn, improve the clinical picture of SCA.

Sickle Cell and α+-Thalassemia Traits Influence the Association between Ferritin and Hepcidin in Rural Kenyan Children Aged 14-26 Months

Background

The relation between subclinical hemoglobinopathies and concentrations of the iron-regulatory hormone hepcidin is not well characterized.

Objective

We investigated the relation of hepcidin concentration with hemoglobinopathies among young children in Kenya.

Methods

We quantified serum hepcidin and ferritin in 435 Kenyan children aged 14-20 mo in a subsample of the Water, Sanitation, and Handwashing (WASH) Benefits Trial. Blood samples were genotyped for α+-thalassemia and for sickle cell disorder. Hepcidin was compared across sickle cell and α+-thalassemia genotypes separately by using generalized linear models, and children who were normozygous for both conditions were also compared with those who had either of these conditions. In the association between hepcidin and ferritin, we assessed effect modification by genotype.

Results

In this population, we found that 16.2% had sickle cell trait and 0.2% had sickle cell disorder, whereas 40.0% were heterozygous for α+-thalassemia and 8.2% were homozygous. Hepcidin concentration did not differ by genotype, but effect modification was found by genotype in the association between hepcidin and ferritin (P < 0.1). Among normozygous sickle cell children (HbAA), there was an association between hepcidin and ferritin (β = 0.92; 95% CI: 0.72, 1.10). However, among those with sickle cell trait (HbAS), the association was no longer significant (β = 0.31; 95% CI: -0.04, 0.66). Similarly, among children who were normozygous (αα/αα) or heterozygous (-α/αα) for α+-thalassemia, hepcidin and ferritin were significantly associated [β = 0.94 (95% CI: 0.68, 1.20) and β = 0.77 (95% CI: 0.51, 1.03), respectively]; however, in children who were homozygous for α+-thalassemia (-α/-α), there was no longer a significant association (β = 0.45; 95% CI: -0.10, 1.00).

Conclusion

Hepcidin was not associated with hemoglobin genotype, but there may be a difference in the way hepcidin responds to iron status among those with either sickle cell trait or homozygous α+-thalassemia in young Kenyan children. This trial was registered at clinicaltrials.gov as NCT01704105.

Anaemia among females in child-bearing age: Relative contributions, effects and interactions of α- and β-thalassaemia

Introduction

Anaemia in women during pregnancy and child bearing age is one of the most common global health problems. Reasons are numerous, but in many cases only minimal attempts are made to elucidate the underlying causes. In this study we aim to identify aetiology of anaemia in women of child bearing age and to determine the relative contributions, effects and interactions of α- and β-thalassaemia in a region of the world where thalassaemia is endemic.

Methods

A cross sectional study was conducted at the Colombo North Teaching Hospital of Sri Lanka. The patient database of deliveries between January 2015 and September 2016 at University Obstetrics Unit was screened to identify women with anaemia during pregnancy and 253 anaemic females were randomly re-called for the study. Data were collected using an interviewer-administered questionnaire and haematological investigations were done to identify aetiologies.

Results

Out of the 253 females who were anaemic during pregnancy and were re-called, 8 were excluded due to being currently pregnant. Of the remaining 245 females, 117(47.8%) remained anaemic and another 22(9.0%) had non-anaemic microcytosis. Of anaemic females, 28(24.8%) were iron deficient, 40(35.4%) had low-normal serum ferritin without fulfilling the criteria for iron deficiency,18(15.3%) had β-haemoglobinopathy trait and 20(17.0%) had α-thalassaemia trait. Of females who had non-anaemic microcytosis, 14(66.0%) had α-thalassaemia trait. In 4 females, both α- and β-thalassaemia trait coexist. These females had higher levels of haemoglobin (p = 0.06), MCV (p<0.05) and MCH (p<0.01) compared to individuals with only β-thalassaemia trait. A significantly higher proportion of premature births (p<0.01) and lower mean birth weights (p<0.05) were observed in patients with α-thalassaemia trait.

Conclusions

Nearly one third of anaemic females in child bearing age had thalassaemia trait of which α-thalassemia contributes to a majority. Both α- and β-thalassaemia trait can co-exist and have ameliorating effects on red cell indices in heterozygous states. α-Thalassaemia trait was significantly associated with premature births and low birth weight. It is of paramount importance to investigate the causes of anaemia in women of child bearing age and during pregnancy in addition to providing universal iron supplementation.

Females of HbAS genotype have reduced concentration of the malaria protective deoxyhemoglobin S than males

The quantity of the intra-erythrocytic deoxyhemoglobin S (Hb S) affects the level of protection against malaria and also the sickling phenomenon. This study reports on significantly lower concentration of Hb S in females than males. Data came from 350 children, aged 12-47 months who participated in a phase 2b malaria vaccine trial. Hemoglobinopathy and G6PD deficiency typing was necessary to ascertain equal representation of these malaria protective traits across the vaccine cohorts. Hemoglobin types (HbAA, HbAS) and % Hb S were evaluated by HPLC. Alpha thalassemia (alpha-thal) and G6PD genotypes were evaluated by PCR. The overall prevalence for HbAS was 20%, 46% for 3 alpha genes and 10% for 2 alpha genes and 14% for G6PD A-. More females of HbAS/αα/αα genotype had low Hb S than males and had mean % Hb S of 37.5% ± 5.4 SD, compared to 42.0% ± 2.5 SD in males of same genotype (P = 0.018). Consistent with reduction of the malaria protective Hb S in females, parasite load in females was nearly twice that of males but the difference was not statistically significant. The X-chromosome linked G6PD deficiency did not influence the level of Hb S. We conclude that, the low Hb S in these females explains the resultant higher malaria parasite load. We speculate that the low Hb S in females could also explain observations suggesting that the sickling phenomenon tends to be less severe in females than males.

Analysis of Glycosylation Profiles of Serum Glycoprotein from Iron Overload Thalassemia

BACKGROUND

The aim of this study was to use a lectin microarray to detect differential glycan profiling of serous glycoprotein in iron overload thalassemia patients.

METHODS

This study enrolled iron overload α/β-thalassemia patients and no iron overload α/β-thalassemia patients. Lectin microarray was used to detect the alteration of protein glycosylation. The reliability of the lectin microarray results was verified by the lectin blotting technique. Expression level of hepcidin, erythropoietin, ferritin, and transferrin were measured by western blotting. Data were analyzed using the SPSS 16.0 software.

RESULTS

In this study, 19 differentiating lectins were screened from the iron overload α-thalassemia group, and 15 were screened from the iron overload β-thalassemia group. The agglutinin blotting technique demonstrated that the results of the Aleuria aurantia lectin (AAL), Lens culinaris agglutinin (LCA), and Wheat germ agglutinin (WGA) agglutinin affinity for serum glycoproteins were consistent with the results of the lectin microarray. In iron overload thalassemia groups, expression levels of erythropoietin and ferritin were increased, but hepcidin and transferrin were significantly reduced.

CONCLUSIONS

The differentially expressed glycoprotein database of iron overload thalassemia was successfully created, and the specific glycan patterns of serous glycoprotein might be efficient biomarkers for diagnosis or progression of iron overload thalassemia.

Molecular Basis and Genetic Modifiers of Thalassemia

Thalassemia is a disorder of hemoglobin characterized by reduced or absent production of one of the globin chains in human red blood cells with relative excess of the other. Impaired synthesis of β-globin results in β-thalassemia, whereas defective synthesis of α-globin leads to α-thalassemia. Despite being a monogenic disorder, thalassemia exhibits remarkable clinical heterogeneity that is directly related to the intracellular imbalance between α- and β-like globin chains. Novel insights into the genetic modifiers have contributed to the understanding of the correlation between genotype and phenotype and are being explored as therapeutic pathways to cure this life-limiting disease.

Elevations of Thrombotic Biomarkers in Hemoglobin H Disease

BACKGROUND

Thalassemia is a group of hereditary hemoglobinopathies caused by decreased or absent synthesis of α and/or β globin chains. Studies have shown that hypercoagulability and thrombosis are common clinical symptoms in β-thalassemia, especially β-thalassemia intermedia, but little is known about in α-thalassemia. This study aims to examine phosphatidylserine (PS) levels, platelet activation, and coagulation markers in splenectomized (S) and nonsplenectomy (NS) patients with hemoglobin (Hb) H disease.

METHODS

The NS group comprised 20 patients (median age 15.0 years, range, 14-16.5 years), and the S group consisted of 11 patients (median age 16.4 years, range, 14-19.9 years) with Hb H disease; the control group consisted of 20 normal subjects. Hematological parameters were collected. Flow cytometry was used to measure PS exposure on red blood cells. The levels of intercellular adhesive molecule (ICAM)-1, tumor necrosis factor α (TNFα), β-thromboglobulin (TG) and prothrombin fragment 1 + 2 (F1.2) were determined using ELISA test kits.

RESULTS

Significant increases in the levels of PS, ICAM-1, TNFα, β-TG, and F1.2 were observed in both patient groups compared to normal controls (p < 0.01).

CONCLUSION

This observation indicates blood coagulation, endothelial injury, chronic low-grade inflammation, platelet activation, and thrombin generation are present in Hb H disease; these findings merit further assessment in a larger prospective cohort to establish possible links with thrombotic manifestations.

The Prevalence and Role of Hemoglobin Variants in Biometric Screening of a Multiethnic Population: One Large Health System's Experience

OBJECTIVES

To characterize and quantitate hemoglobin (Hb) variants discovered during biometric hemoglobin A1c (HbA1c) analyses in a large multiethnic population with a focus on the effect of variants on testing method and results.

METHODS

In total, 13,913 individuals had their HbA1c measured via ion-exchange high-performance liquid chromatography. Samples that had a variant Hb detected or HbF fraction more than 25% underwent variant Hb characterization and confirmation by gel electrophoresis. RBC indices were also evaluated for possible concomitant thalassemia.

RESULTS

Of the 13,913 individuals evaluated, 524 (3.77%) had an Hb variant. The prevalence of each variant was as follows: HbS trait (n = 396, 2.85%), HbSS disease (n = 4, 0.03%), HbC trait (n = 85, 0.61%), HbCC disease (n = 2, 0.01%), HbSC disease (n = 5, 0.04%), HbE trait (n = 18, 0.13%), HbD or G trait (n = 9, 0.06%), HbS β-thalassemia + disease (n = 1, 0.01%), hereditary persistence of HbF (n = 2, 0.01%), and HbMontgomery trait (n = 1, 0.01%). Concomitant α-thalassemia was detected in 20 (3.82%) of the 524 individuals with an Hb variant.

CONCLUSIONS

This study represents one of the largest epidemiologic investigations into the prevalence of Hb variants in a North American metropolitan, multiethnic workforce and their dependents and reinforces the importance of method selection in populations with Hb variants.

Management and Outcomes of Fetal Hydrops in a Tertiary Care Centre in Singapore

Introduction: Fetal hydrops is a serious condition which can be caused by immune and non-immune aetiologies. We aimed to review the management of fetal hydrops at our hospital. Materials and Methods: A retrospective review of all cases of fetal hydrops diagnosed in our institution from 2006 to 2013 was carried out. Results: Out of the 30 cases of fetal hydrops diagnosed antenatally, 17 were cases of Bart's hydrops which were all terminated in-utero. Of the remaining 13 cases, 11 cases consisted of non-immune causes of hydrops. Planned antenatal interventions including in-utero blood transfusions (n = 4) and thoracentesis (n = 5) as well as planned caesarean deliveries (n = 11) were performed in the majority of cases. Postnatal neonatal intensive care with interventions including chest drainage and transfusions were also performed. A majority, 92%, of the cases survived the perinatal period following a variable length of hospital stay ranging from a week to 3 months. Conclusion: Management of fetal hydrops is complex. Close coordination between the obstetric and neonatal teams was the key to good short-term survival of neonates with antenatally diagnosed hydrops, as it allows timely antenatal intervention and anticipation of potential perinatal complications.

Hb lepore/β0-thalassaemia with α+-thalassaemia interactions, a potential diagnostic pitfall

Haemoglobin (Hb) Lepore is a variant Hb consisting of two α-globin and two δβ-globin chains. In a heterozygote, it is associated with clinical findings of thalassaemia minor, but interactions with other haemoglobinopathies can lead to various clinical phenotypes and pose diagnostic challenges. We reported a pair of siblings from a Malay family, who presented with pallor and hepatosplenomegaly at the ages of 21 months and 14 months old. The red cell indices and peripheral blood smears of both patients showed features of thalassaemia intermedia. Other laboratory investigations of the patients showed conflicting results. However, laboratory investigation results of the parents had led to a presumptive diagnosis of compound heterozygote Hb Lepore/β-thalassaemia and co-inheritance α+-thalassaemia (-α3.7). Hb Lepore has rarely been detected in Southeast Asian countries, particularly in Malaysia. These two cases highlight the importance of family studies for accurate diagnosis, hence appropriate clinical management and genetic counseling.

First example of an FY*01 allele associated with weakened expression of Fya on red blood cells

Duffy antigens are important in immunohematology. the reference allele for the Duffy gene (FY) is FY*02, which encodes Fy(b). An A>G single nucleotide polymorphism (SNP) at coding nucleotide (c.) 125 in exon 2 defines the FY*01 allele, which encodes the antithetical Fy(a). A C>T SNP at c.265 in the FY*02 allele is associated with weakening of Fy(b) expression on red blood cells (R BCs) (called Fy(x)). until recently, this latter change had not been described on a FY*01 background allele. Phenotype-matched units were desired for a multi-transfused Vietnamese fetus with α-thalassemia. Genotyping of the fetus using a microarray assay that interrogates three SNPs (c.1-67, c.125, and c.265) in FY yielded indeterminate results for the predicted Duffy phenotype. Genomic sequencing of FY exon 2 showed that the fetal sample had one wild-type FY*01 allele and one new FY*01 allele with the c.265C>T SNP, which until recently had only been found on the FY*02 allele. Genotyping performed on samples from the proband's parents indicated that the father had the same FY genotype as the fetus. Flow cytometry, which has been previously demonstrated as a useful method to study antigen strength on cells, was used to determine if this new FY*01 allele was associated with reduced Fy(a) expression on the father's RBCs. Median fluorescence intensity of the father's RBCs (after incubation with anti-FY(a) and fluorescein-labeled anti-IgG) was similar to known FY*01 heterozygotes. and significantly weaker than known FY*01 homozygotes. In conclusion, the fetus and father both had one normal FY*01 allele and one new FY*01W.01, is associated with weakened expression of Fy(a) on RBCs.

[Molecular bases of α-thalassemia in Argentina]

The α-thalassemia is one of the most common hereditary disorders worldwide. Currently, molecular diagnostics is the only available tool to achieve an accurate diagnosis. The purpose of this study was to characterize the molecular bases of these syndromes in our environment and to establish genotype-phenotype associations. Through a combination of different molecular techniques and fluorescent in situ hybridization (FISH),we were able to find α-thalassemic mutations in 145 of the 184 patients (78.8%) studied with hematological parameters compatible with α-thalassemia. Deletions of the α-globin genes resulted the major molecular cause of the disease, and the most frequent mutation was -α(3.7), found in homozygous and heterozygous genotypes. In patients with α° phenotypes, other prevalent mutations were( _MED) and (_CAL/CAMP). The description of a sub-telomeric deletion in a patient with α-thalassemia and mental retardation was also achieved. β-thalassemic mutations in heterozygous state were found in 7.6% of the patients, who presented α-thalassemic clinical features (microcytosis and Hb A₂levels below 3.5%). Hematologic profiles for the α+ and α° genotypes were established for adult and pediatric patients. Hopefully, this work will provide guidelines for the detection of possible α-thalassemic carriers. It also highlights the collaborative work of hematologists, the biochemical and molecular biology laboratory and genetists, in order to provide appropriate genetic counseling.

Treatment of alpha(0)-thalassemia (--(SEA)/--(SEA)) via serial fetal and post-natal transfusions: Can early fetal intervention improve outcomes?

OBJECTIVE AND IMPORTANCE

Homozygous Southeast Asian alpha-thalassemia mutation (--(SEA)/--(SEA)) results in deletion of all alpha-globin genes (alpha(0)-thalassemia). Since all alpha-globin chains are absent, hemoglobin F cannot be synthesized, and hemoglobin Bart's becomes the dominant fetal hemoglobin. Hemoglobin Bart's is a γ tetramer with a very high oxygen affinity, thus oxygen delivery to the tissues is poor. Clinical manifestations include severe fetal anemia, hydrops fetalis, fetal demise, and high risk of neurodevelopmental impairment in the rare survivors.

CLINICAL PRESENTATION

A 39-year-old Vietnamese woman presented to our center at 28 0/7 weeks' gestation with fetal alpha(0)-thalassemia (--(SEA)/--(SEA) type deletion) and ultrasound markers suggestive of severe fetal anemia.

INTERVENTION

The fetus was treated with four intrauterine transfusions followed by post-natal chronic transfusions. Formal neurodevelopmental testing (Battelle Developmental Inventory, Second Edition) was performed at 18 months of age, and the developmental quotient was 93 (32nd percentile) with all subdomains noted within normal limits, indicating overall intact neurodevelopment.

CONCLUSION

We posit that earlier diagnosis and fetal treatment, prior to clinical findings suggestive of fetal anemia, may improve long-term outcomes by enhancing oxygen delivery to the tissues of the developing fetus.

Frequency of beta-thalassemia or beta-hemoglobinopathy carriers simultaneously affected with alpha-thalassemia in Iran

BACKGROUND

Beta-thalassemias are prevalent heritable single gene disorders affecting the quantity of the hemoglobin molecule. Rarely, a co-inheritance of these impairments with alpha-thalassemia and/or a hemoglobinopathy occurs and makes an important double heterozygote or homozygous state. Thus finding these cases is essential for genetic counseling. The present study aimed to identify the prevalence of coexistent alpha-thalassemia mutations, hemoglobinopathies, and beta-thalassemia determinants.

METHODS

This descriptive study was performed on 5760 patients. We used complete blood cell count, Hb electrophoresis, and HbA2 measurement for thalassemia carrier identification. Increased HbA2 (> or = 3.5%) is the standard diagnostic marker for beta-thalassemia, while normal HbA2 with low MCH and MCV can indicate an alpha-thalassemia carrier or atypical beta-thalassemia minor. Individuals with MCV < 80 fL, MCH < 27 pg, and hemoglobin < or = 15.3 g/dL in men or < or = 14 g/dL in women, were candidates for molecular thalassemia investigations. Patients with abnormal hemoglobin varieties in hemoglobin electrophoresis were referred to a genetics laboratory for hemoglobinopathy detection.

RESULTS

141 subjects out of 5760 were affected by alpha and beta-thalassemia or a beta-hemoglobinopathy simultaneously, including: 13 (11.1%) fetuses, 55 (38.2%) male cases, and 73 (50.7%) females. Among these 141 alpha-thalassemia patients, 92 cases (65.24%) were beta-thalassemia carriers and 3 (2.12%) were beta-thalassemia major, 43(30.49%) had beta-hemoglobinopathies, and 3 cases (2.12%) had co-inherited beta-thalassemia and variant hemoglobins. 31 beta-gene mutations were observed in this population, the most common being HbS Cd6 (A > T) (24%). These thalassemia determinants account for about 46% of all detected mutations. As for alpha-gene mutations, -3.7 detection was the most prevalent.

CONCLUSIONS

The relatively high prevalence of co-inherited alpha-thalassemia and hemoglobinopathies among beta-thalassemia carriers indicates the importance of molecular analysis to diagnose these double heterozygous or sole homozygous cases for prenatal diagnostic purposes and putting forth strategies to prevent more complicated and dangerous combinations.

The co-inheritance of alpha-thalassemia and sickle cell anemia is associated with better hematological indices and lower consultations rate in Cameroonian patients and could improve their survival

Background

Co-inheritance of α-thalassemia was reported to be associated with a delayed age of disease onset among Cameroonian Sickle Cell Anemia (SCA) patients. The present study aimed to explore the correlation between α-thalassemia, hematological indices, and clinical events in these patients.

Methods and Findings

We studied 161 Cameroonian SCA patients and 103 controls (59.1% HbAA) with median ages of 17.5 and 23 years. RFLP-PCR was used to confirm SCA genotype and to describe haplotypes in the HBB-like genes cluster. Multiplex Gap-PCR was performed to investigate the 3.7 kb α-globin gene deletions. SNaPshot PCR, capillary electrophoresis and cycle sequencing were used for the genotyping of 10 SNPs in BCL11A, HMIP1/2, OR51B5/6 and HBG loci, known to influence HbF levels. Generalised linear regression models adjusted for age, sex and SNPs genotypes was used to investigate effects of α-thalassemia on clinical and hematological indices. The median rate of vaso-occlusive painful crisis and hospitalisations was two and one per year, respectively. Stroke was reported in eight cases (7.4%). Benin haplotype was the most prevalent (66.3%; n = 208 chromosomes). Among patients, 37.3% (n = 60) had at least one 3.7 kb deletion, compared to 10.9% (n = 6) among HbAA controls (p<0.001). Among patients, the median RBC count increased with the number of 3.7 kb deletions [2.6, 3.0 and 3.4 million/dl, with no, one and two deletions (p = 0.01)]. The median MCV decreased with the number of 3.7 kb deletion [86, 80, and 68fl, with no, one and two deletions (p<0.0001)], as well as median WBC counts [13.2, 10.5 and 9.8×10⁹/L (p<0.0001. The co-inheritance of α-thalassemia was associated with lower consultations rate (p = 0.038).

Conclusion

The co-inheritance of α-thalassemia and SCA is associated with improved hematological indices, and lower consultations rate in this group of patients. This could possibly improve their survival and explain the higher proportion of α-thalassemia among patients than controls.

Efficiency of recombinant erythropoietin administration in hemoglobinopathy H

Alpha-thalassemia is widely spread in human population and one of the most common types of α-thalassemia is hemoglobinopathy H which develops with mild microcytic hypochromic anemia, hepatosplenomegaly and jaundice. The basic method of anemia correction is blood transfusion. However this method has crucial deficiencies. As it is known recombinant erythropoetin (rEPO) contributes to erythroid proliferation and could be used for anemia treatment. The aim of the study was to qualify efficiency of administration rEPO in complex therapy of hemaglobinopathy H. Study involved irregularly transfused 14 patients with hemoglobinopathy H (2 males and 12 females). Control group included 30 healthy persons. Recombinant erythropoietin (Eprex) administrated hypodermically 10,000 units 3 times a week during 6 months. Average hemoglobin level before treatment was 62 g/l. Responses to the rEPO treatment varied from 9 to 70 g/l, 9 (64%) of patients had a good response, showed an increase in hemoglobin level more than 20 g/l. In 4 patients (29%) had a moderate response (10-20 g/l), but only in 1 (7%) patient occurred poor response. Changing the parameters of erithrocyte indices, hemoglobin fractions, serum iron and serum ferritin level are not statistically significant. It can be concluded that the use of rEPO in complex therapy of hemaglobinopathy H, leads to increased levels of hemoglobin and consequently reducing the need for blood transfusions.

A newly modified hemoglobin H inclusion test as a secondary screening for α(0)-thalassemia in Southeast Asian populations

Screening for α(0)-thalassemia is usually associated with a high false-positive rate, leading to an unnecessary PCR workload for accurate diagnosis. We have developed a modified Hb H inclusion test for use as a secondary screening. This test was performed on young red blood cell enriched fractions using dextran sedimentation. The study was performed in 100 subjects positive on initial screening. Confirmatory tests included Hb analysis and a multiplex PCR assay to identify α(0)-thalassemia deletions. A modified Hb H inclusion test was positive in 31 cases, 30 of whom were α(0)-thalassemia carriers (97%). The remaining case (3.0%) was homozygous for α(+)-thalassemia. The remaining 69 cases with a negative Hb H inclusion test included normal subjects, α(+)-thalassemia carriers and β-thalassemia carriers. Two of them (2/69, 3.0%) were found to be double heterozygotes for β(0)-thalassemia and α(0)-thalassemia. The overall sensitivity and specificity of the modified Hb H inclusion test for screening of α(0)-thalassemia were 94.0 and 99.0%, respectively. Therefore, we recommend the use of this test in combination with Hb analysis to exclude cases with αβ-thalassemia. This should lead to a significant reduction in the number of cases referred for PCR analysis of α(0)-thalassemia by about 50.0%.

Fetal cardiac circumference derived by spatiotemporal image correlation as a predictor of fetal hemoglobin Bart disease at midpregnancy

OBJECTIVES

The purpose of this study was to evaluate the efficacy of the fetal cardiac circumference derived by spatiotemporal image correlation (STIC) for predicting fetal hemoglobin (Hb) Bart disease.

METHODS

Pregnancies at risk of fetal Hb Bart disease at 17 to 22 weeks' gestation were enrolled. All underwent STIC volume acquisition for analysis of fetal cardiac dimensions and cordocentesis for Hb level and Hb typing analysis. Spatiotemporal image correlation volume data sets were subsequently analyzed offline for cardiac circumference measurements, which were used to evaluate the efficacy in predicting fetal anemia and fetal Hb Bart disease.

RESULTS

A total of 88 pregnancies at risk of fetal Hb Bart disease at 17 to 22 weeks were recruited into the study. The cardiac circumference was significantly higher in fetuses with Hb Bart disease than in unaffected fetuses (1.33 and 1.02 multiples of the median [MoM], respectively; P < .001). The cardiac circumference effectively predicted fetal Hb Bart disease (area under the receiver operating characteristic curve, 0.85; 95% confidence interval [CI], 0.73-0.97), with sensitivity of 86.4% (95% CI, 72.0%-100%) and specificity of 78.1% (95% CI, 68.0%-88.3%) using a cutoff point of greater than 1.17 MoM, whereas the cardiothoracic ratio had better efficacy, with sensitivity of 90.9% (95% CI, 78.9%-100%) and specificity of 85.9% (95% CI, 77.4%-94.5%) using a cutoff point of greater than 0.50.

CONCLUSIONS

At midpregnancy, a cardiac circumference of greater than 1.17 MoM can be used as an alternative sonographic marker for predicting fetal Hb Bart disease, although not perfectly. However, the cardiothoracic ratio seems to be more accurate than the cardiac circumference for such a purpose.

Comparison of hematocrit/hemoglobin ratios in subjects with alpha-thalassemia, with subjects having chronic kidney disease and normal subjects

The ratio of hematocrit (Hct) to hemoglobin (Hb) in the people with normal red blood cell (RBC) morphology is generally three to one. We studied Hct/Hb ratios among patients with alpha-thalassemias (Hb H, H-CS, AEBart, AEBart-CS, EFBart and EFBart-CS diseases) diagnosed by high performance liquid chromatography, and compared them with normal subjects and with patients having anemia due to chronic kidney disease (CKD). The Hct and Hb levels were derived by automated analyzer. The means +/- SD of the Hct/Hb ratios were 3.5 +/- 0.2 (range 3.3 - 4.1), 3.0 +/- 0.1 (range 2.9 - 3.2) and 3.0 +/- 0.1 (range 2.8 - 3.2) in the alpha-thalassemia, normal and CKD groups, respectively. The mean Hct/Hb ratio in subjects with alpha-thalassemia was higher than the mean in normal subjects and in those with CKD. The Hct/Hb ratios for each genotype of the alpha-thalassemia were not different from each other. The underlying mechanisms for the higher Hct/Hb ratio among those with alpha-thalassemia are theorized to be less density and/or more hydration of a-thalassemia RBCs, more entrapment of plasma in the spun RBC, the high percent of nucleated RBC and WBC interference. A ratio of 3.5 +/- 0.2 may be helpful in cases of moderate anemia when typing only shows Hb A and E, to consider investigation for alpha-thalassemia, or in cases of alpha-thalassemia with acute blood loss, if the Hct is less than 35%, in the decision to transfuse.

[Raman spectra of different kinds of thalassemia erythrocytes with the effect of pH]

Thalassemia is a kind of blood diseases which has high morbidity and large influence. Previous methods for diagnosis are all very cumbersome and time consuming. By comparing Raman spectra of different kinds of thalassemia and normal erythrocytes at acid or alkaline pH, it was found that beta-thalassemia and alpha-thalassemia erythrocytes have dissimilar Raman spectra in the acidic environment, such as the Raman spectra of beta-thalassemia erythrocytes showed higher intensity at the characteristic bands assigned to oxyhemoglobin, and the characteristic bands assigned to deoxyhemoglobin were even completely replaced; beta-thalassemia erythrocytes membrane has a smaller chain interaction between the transverse order parameters than normal erythrocytes, and the S(lat) values are different for different stages of anemia, while the S(lat) values are similar between alpha-thalassemia and normal erythrocytes, indicating that based on the effect of pH it is possible to diagnose thalassemia more quickly by using Raman spectra.

Hematological characterization of compound heterozygous hemoglobin Hope/E patients with and without alpha-thalassemia-1 SEA type deletion

BACKGROUND

There is no report of hematological data in patients with co-inheritance of compound heterozygous hemoglobin (Hb) Hope/E and alpha-thalassemia-1 Southeast Asian (SEA) type deletion.

METHODS

Hematological parameters were studied in 3 Thai patients with compound heterozygous Hb Hope/E and 1 of them had alpha-thalassemia-1 SEA type deletion. Red cell counts, hemoglobin, hematocrit, and red cell indices were measured using an automated blood counter. The molecular analysis of Hb Hope was performed using the amplification refractory mutation system (ARMS)-PCR.

RESULTS

The lowest levels of hemoglobin, hematocrit, MCV, MCH, and HbA2/E and the highest level of RDW were found in a patient who had co-inheritance of compound heterozygous Hb Hope/E and alpha-thalassemia-1 SEA type deletion.

CONCLUSIONS

Co-inheritance of compound heterozygous Hb Hope/E and alpha-thalassemia-1 SEA type deletion caused prominent changes in hematological features. Thus, knowledge and understanding of these multiple gene interactions will assist in diagnosis, management, and counseling in these patients.

[Analysis of hematological characteristics on the 79 co-inheritance of α-thalassemia and β-thalassemia carriers in Guangxi]

OBJECTIVE

To investigate the hematological characteristics of co-inheritance of α-thalassemia (α-thal) and β-thalassemia (β-thal) and to survey the incidence of co-inheritance of α-thal and β-thal in Guangxi.

METHODS

DNA samples from 370 primary and middle school students who were β-thal carriers in Guangxi were further processed for the α-goblin gene mutation screening, and were grouped based on the genotype of β- and α-goblin gene. The hematological indexes to the different groups were compared by One-way ANOVA.

RESULTS

Of the total 370 β-thal carriers, 79 were found to carry α-thal, which gave a frequency of 21.35% for β-thal carriers and 1.36% for coincidence of these two common disorders in the local population. As expected, the 79 patients presented very variable α-globin alterations in combination with β-globin mutations, showing 31 genotype combined with the coincidence of both Hb disorders. Except the genotypes of 3 β-thal heterozygotes combined with ααα(anti3.7) triplication and 2 β-thal carriers with IVS-II-654(C→T)/N combined-α(3.7)/αα presented the phenotype of thalassemia intermedia, and other 74 carriers with co-inheritance of α-thal and β-thal all presented the phenotype of β-thal trait. There were significant differences between β-thal heterozygotes and the carriers with a co-inheritance of both β+α(0) thal in MCH, MCV and Hb. In addition, there existed significant difference between the carriers with a co-inheritance of both β+α(+) thal and a co-inheritance of both β+α(0) thal in MCV, MCH and Hb.

CONCLUSION

Compared to that of β-thal heterozygotes, the carriers with a co-inheritance of α-thal and β-thal had slighter phenotype with hematological characteristics. It's difficult to distinguish the double heterozygotes with the co-inheritance of α-thal and β-thal from β-thal heterozygotes by hematological indexes, the molecular diagnosis should be performed.

Hemoglobin Pyrgos with hemoglobin H disease: new triple heterozygosity

A 19-year old Thai male presented to the hospital with fever, acute hemolysis, pallor and jaundice without hepatosplenomegaly. On admission his hematocrit was 17.4% and a blood smear showed moderate hypochromia with mild anisopoikilocytosis. Hemoglobin (Hb) electrophoresis revealed Hb A2ABart's Hb H with an abnormal band, which on PCR proved to be Hb Pyrgos (beta83, glycine --> aspartic acid). The patient inherited beta(Pyrgos) globin from his mother and alpha-thalassemia-1 from his father. He was diagnosed as having Hb H (alpha-thalassemia-1/alpha-thalssemia-2) heterozygous Hb Pyrgos. He was treated with a transfusion of packed red blood cells. During follow-up his hematocrits ranged from 31 to 34%. The Hb Pyrgos did not add any deleterious effect to his Hb H disease.

Genetic origin and interaction of the Filipino β⁰-thalassemia with Hb E and α-thalassemia in a Thai family

We describe hematologic and molecular characteristics of a hitherto undescribed interaction between the Filipino deletional β⁰-thalassemia with Hb E and α-thalassemia in a Thai family. This study was conducted during the prenatal screening of a pregnant Thai woman and her family members. A prenatal diagnosis was performed at her second pregnancy by amniocentesis. Laboratory investigations identified that the pregnant woman was Hb E heterozygote with α⁺-thalassemia, whereas her husband was a double heterozygote for the Filipino deletional β⁰-thalassemia and α⁺-thalassemia. Their affected son was a patient with a previously undescribed condition of Hb E-β⁰-thalassemia with α⁺-thalassemia. Both a combined gap-polymerase chain reaction (PCR) and allele-specific PCR were used successfully in the prenatal diagnosis, which identified an affected fetus with Hb E-β⁰-thalassemia without α⁺-thalassemia. Beta globin gene haplotype analysis indicated the same origin of this Filipino β⁰-thalassemia in Asian populations.

[Spectrum of gene deletion in 471 children with α-thalassemia]

OBJECTIVE

To study the distribution of common α-thalassemia gene deletion in children.

METHODS

Blood cell analysis was performed on children who visited the clinic of the Foshan Women and Children's Hospital. Blood samples (2 mL, EDTA anticoagulant) was collected from children with MCV<82 fl for analysis of α-thalassemia gene using the GAP-PCR method.

RESULTS

MCV<82 fl was found in 1341 children. Of the 1341 children, 471 (35.1%) were diagnosed with α-thalassemia. The prevalence of α-thalassemia increased with increasing age. --SEA was a major type of α-thalassemia gene deletion (75.3%), followed by -a3.7 (17.0%) and -a4.2 (7.7%) in the 471 patients. The top three genotypes were --SEA/aa (73.2%), aa/-a3.7 (12.5%) and --SEA/-a3.7 (5.5%).

CONCLUSIONS

Genetic testing is necessary for the diagnosis of α-thalassemia in children with MCV<82 fl. --SEA is a common type of α-thalassemia gene deletion, and -SEA/aa is a common gene type of α-thalassemia in the subjects of this study.

[Hematologic parameters and genotype analysis in 166 children with HbH disease in the North Guangxi region]

OBJECTIVE

To study the characteristics of genotype spectrum and hematologic parameters in children with HbH disease in the North Guangxi region.

METHODS

HbH disease was identified by clinical manifestations, routine blood tests and hemoglobin electrophoresis in 166 children who came form the North Guangxi region. Genotypes were determined by Multi-PCR combined with PCR reverse dot blot. DNA sequencing was used when the genotype could not be identified by regular methods.

RESULTS

Of the 166 children with HbH disease, 8 genotypes were identified: --SEA/-α3.7 (82 cases), --SEA/-α4.2 (40 cases), --SEA/αCSα (38 cases), --SEA/αQSα (1 case), --SEA/αWSα (1 case), --SEA/αCD43/44 (-C) α (1 case), --SEA/-α3.7 plus CD17 (A→T) (1 case) and --SEA/-α4.2 plus CD41-42(-TTCT) (1 case). One case was confirmed as the heterozygote of --SEA and an unknown mutation. In the 134 cases with complete medical data, 2 had normal hemoglobin levels, 36 manifested mild anemia, 90 manifested moderate anemia, and 6 (genotype: --SEA/αCSα) showed severe anemia because of the coexistence of infection. Children with the genotype of --SEA/-α3.7 (69 cases), --SEA/-α4.2 (31 cases) and --SEA/αCSα (34 cases) had hemoglobin levels of 62-120, 69-127 and 34-110 g/L respectively. The hemoglobin level in the --SEA/αCSα group was significantly lower than in the deletional HbH disease group (genotypes: --SEA/-α3.7 and --SEA/-α4.2 ) (P<0.05). In contrast, MCV levels in the --SEA/αCSα group were significantly higher than in the deletional HbH disease group (P<0.05).

CONCLUSIONS

The genotype spectrum of HbH disease is diverse in the North Guangxi region. Deletional genotype is prevalent. The disease is heterogeneous. The children with --SEA/αCSα HbH disease have severer anemia and higher MCV levels than those with deletional HbH disease.

[The value of MCV, MCH and HbA(2) in laboratory screening of thalassemia]

OBJECTIVES

To explore the roles of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and hemoglobin A(2) (HbA(2)) in the laboratory screening of thalassemia, and to find optimal screening modality for different conditions.

METHODS

From September 2008 to May 2011, 1384 subjects underwent thalassemia screening at Department of Obstetrics and Gynecology of Nanfang Hospital. Of them, 1036 cases were diagnosed with thalassemia (408 α-thalassemia, 608 β-thalassemia, and 20 αβ compound thalassemia, thalassemia group) and 348 without thalassemia, non-thalassemia group. All subjects were screened respectively for MCV, MCH and HbA(2). Analyses were performed in all subjects to assess the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy respectively associated with MCV, MCH and HbA(2) alone, combination of MCV and MCH, and combination of MCV, MCH and HbA(2).

RESULTS

(1) In the thalassemia group, the sensitivity of MCV alone was 92.9% (379/408) for α thalassemia, 99.3% (604/608) for β thalassemia and 100.0% (20/20) for αβ compound thalassemia. In the non-thalassemia group, the specificity of MCV alone was 75.0% (261/348). (2) In the thalassemia group, the sensitivity of MCH alone was 92.9% (379/408) in α thalassemia, 99.0% (602/608) in β thalassemia and 100.0% (20/20) in αβ compound thalassemia. In the non-thalassemia group, the specificity of MCH alone was 72.7% (253/348). (3) The sensitivity of Hb A(2) alone was 67.4% (275/408) for α thalassemia, 97.5% (593/608) for β thalassemia, and 100% (20/20) for αβ compound thalassemia while it's specificity was 72.4% (252/348) in the non-thalassemia group. (4) With positive indexes of MCV, MCH and MCV + MCH, when HbA(2) > 3.5% it had a high value in β-thalassemia screening, but when HbA(2) < 2.5% it had little value in α-thalassemia screening. (5) As a single marker, MCV and MCH had better sensitivity, specificity, positive predictive value, negative predictive value and diagnosis accuracy than HbA(2). MCV + MCH was the best for overall screening, but for β thalassemia screening, MCV + MCH + HbA(2) was the best.

CONCLUSIONS

MCV and MCH are suitable for epidemic screening in a large population, physical examination and premarital check-up. Hb electrophoresis and thalassemia gene diagnosis are recommended for subjects with positive MCV and MCH indexes. Diagnoses of α and β-thalassemia gene are recommended for pregnant women with positive MCV and MCH indexes.

Semi-nested Taqman real-time quantitative PCR for noninvasive prenatal diagnosis of Bart's hydrops fetalis

BACKGROUND

Non-invasive prenatal diagnosis based on detection of fetal cell-free DNA is limited when mother and father are both carriers for the same autosomal recessive mutation.

OBJECTIVE

Develop the semi-nested Taqman real-time PCR for quantification of alpha-thalassemia-1 SEA type deletion allele in plasma of alpha-thalassemia-1 SEA carriage pregnancies.

MATERIAL AND METHOD

Plasma DNA was extracted from six women who carried fetuses with normal, 11 with heterozygote alpha-thalassemia-1 SEA type deletion and seven with Bart's hydrops fetalis. DNA was amplified using conventional PCR with the primary specific primer set for alpha-thalassemia-1 SEA type deletion. PCR product was then subjected to the semi-nested real-time PCR using the secondary specific primer and Taqman probe set for alpha-thalassemia-1 SEA type deletion. The standard curve was constructed using ten-fold serial dilutions of conventional PCR product of the heterozygote alpha-thalassemia-1 SEA type deletion.

RESULTS

Women who carried fetuses with Bart's hydrops fetalis displayed a trend toward higher mean copy number of alpha-thalassemia-1 SEA type deletion allele vs. women who carried fetuses with normal and heterozygote, albeit not reaching statistical significance.

CONCLUSION

The maternally inheritedfetal allele present in maternal plasma is difficult to discern the fetal cell-free DNA from a higher background DNA of the mother Thus, further investigation is needed to improve the diagnosis ofBart's hydrops fetalis using this technique.

Re-emergence of late presentations of fetal haemoglobin Bart's disease in Hong Kong

OBJECTIVES

To compare early and late presentations of fetal haemoglobin Bart's disease in the Kowloon West Cluster in Hong Kong, and to find reasons for the re-emergence of late presentations.

DESIGN

Case series with internal comparisons.

SETTING

Two tertiary obstetric units in Hong Kong.

PATIENTS

All cases with confirmed diagnosis of fetal haemoglobin Bart's disease from 1 January 2000 to 31 December 2009.

PRIMARY OUTCOME

antenatal care in the current pregnancy.

SECONDARY OUTCOMES

clinical presentations, ultrasound features, and pregnancy outcomes.

RESULTS

A total of 59 cases (46 early presentations and 13 late presentations) of fetal haemoglobin Bart's disease were identified during the study period. All the late presentations were identified from year 2003 onwards. Late presentations were significantly associated with non-eligible obstetric patients (69% vs 11%; P<0.001), non-booked status at our antenatal service (62% vs 0%; P<0.001), and unavailability of partner's mean corpuscular volume status (23% vs 0%; P=0.009). Mothers presenting late were more likely to have symptoms or signs (85% vs 0%; P<0.001) and to suffer from gestational hypertensive disorder (54% vs 0%; P<0.001). Ultrasound features of these pregnancies included cardiomegaly (94%), placentomegaly (98%), and hydrops fetalis (77%). All pregnancies presenting early were either legally terminated or miscarried. The perinatal mortality in late presentations was 85%.

CONCLUSION

The re-emergence of late presentations of fetal haemoglobin Bart's disease after 2003 was related to influx of non-eligible obstetric patients without proper antenatal screening and diagnosis of thalassaemia. Maternal low mean corpuscular volume and characteristic prenatal ultrasound features such as cardiomegaly, placentomegaly, and hydrops fetalis are useful for detecting affected pregnancies in this group of patients. Better education of both patients and doctors is necessary to explain the importance of early diagnosis of the disease and the seriousness of complications due to late presentations, so as to reduce undesirable maternal and perinatal outcomes.

Accuracy of immunochromatographic strip test in diagnosis of alpha-thalassemia-1 carrier

OBJECTIVE

To determine the accuracy of alpha-thal immunochromatographic (IC) strip in diagnosis of alpha-thalassemia 1 carrier among pregnant women, using PCR for alpha-thalassemia 1 (SEA type) as a gold standard.

MATERIAL AND METHOD

Asymptomatic pregnant women attending the antenatal care clinic were recruited Their blood samples were taken for IC Strip Test (alpha Thal IC strip, i+Med Laboratories Company Limited) in predicting alpha-thalassemia 1 carrier and separately sent for PCR for diagnosis of alpha-thalassemia 1 carrier as a gold standard

RESULTS

Four hundred ninety nine pregnant women were recruited into the present study at various gestational weeks. The accuracy of alpha-Thal IC strip test was relatively high as shown in Table 1. Of them, 62 cases were proven to be alpha-thalassemia 1 trait and all ofthem had the results of positive IC strip, giving a sensitivity of 100%. However 45 pregnant women of non-alpha-thalassemia 1 trait had positive test, giving a specificity of 89%.

CONCLUSION

The present study was solid evidence for clinical application of alpha-thal IC strip in screening program of thalassemia to reduce the need for PCR in diagnosis of a-thalassemia 1 carrier because of its very high sensitivity. The negative test reassures the non alpha-thalassemia 1 carrier status. Moreover, due to its simplicity, convenience to use, low cost, less-time consuming, clear interpretation and no need for either equipment or expensive laboratories, it may probably be very helpful in a massive screening program.

[No deletion alpha thalassaemia in Spain. Abnormal hematological index and molecular study]

The alpha thalassaemia diseases in most cases are caused by deletions that affect one or two of the alpha genes, being less frequent the cases due to punctual mutations, insertions or deletions of a few pairs of bases, which have been denominated no deletion a thalassaemias. The objective of this investigation was to determine the incidence of the no deletion alpha thalassaemia in patients with a thalassaemia using molecular biology techniques. We studied 517 individuals of the San Carlos Hospital (Thalassemia Molecular Research Center, Madrid-Spain) between January 2001 and December 2003, in whom iron deficiency anemia had been ruled out, that presented microcytosis and hypochromia and that presented normal HbA2, HbF and EEF from normal Hbs. The two types of no deletion a thalassaemia most frequently described in the Mediterranean were studied: 1) alpha Hph due to deletion of 5bp in the IVS I and 2) alphaNco due to a change in the initiation codon of the gene. Of the 517 cases studied, 40 (7.7% of the cases) represented a no deletion alpha thalassaemia. Of these cases, 28 were positive for alphaHph of the alpha2 gene, 24 in the heterozygote state, one homozygote and three double heterozygotes associated with the 3,7 kb deletion. The remaining 12 cases were positive for the alphaNco of the alpha2 gene, 10 heterozygotes, one homozygote and one double heterozygote associated with the 4,2 kb deletion. The no deletion alpha thalassaemias represent < 8% from the cases in our environment. The alphaHph is the most frequent type of no deletion a thalassaemia and its haematological abnormalities are more manifest that the ones present in the cases of alphaNco.

A first report on Hb Q-Iran in association with alpha-thalassemia in a case of spinal ischemia

BACKGROUND

Hemoglobin Q-Iran is a rare variant which has not been described in association with alpha-thalassemia to date. We present the case of a Turkish patient who developed spinal ischemia.

METHODS

Spinal ischemia was diagnosed clinically, via magnetic resonance imaging and angiographically. Blood samples were analyzed by high performance liquid chromatography, electrophoresis, gene sequencing, hematological and biochemical analysis.

RESULTS

We detected hemoglobin Q-Iran in association with alpha-thalassemia. The same hemoglobinopathy was detected in two members of the patient's family.

CONCLUSIONS

As various differential diagnosis approaches failed to reveal the cause of spinal ischemia, the combined hemoglobinopathy was eventually postulated.

Analysis of real-time PCR cycle threshold of alpha-thalassemia-1 Southeast Asian type deletion using fetal cell-free DNA in maternal plasma for noninvasive prenatal diagnosis of Bart's hydrops fetalis

BACKGROUND

Noninvasive prenatal diagnosis based on detection of fetal cell-free DNA is hampered when mother and father are both carriers for the same autosomal recessive mutation.

OBJECTIVE

To compare the diagnosis of Bart's hydrops fetalis using conventional Gap-PCR analysis of fetal cells/tissues with the measurement of quantitative difference (deltaCp) between alpha-thalassemia-1 SEA type deletion gene (C(T-mutant)) and wild type alpha-globin gene (C(T-wild type)) in plasma of pregnancies by using the Taqman real-time quantitative PCR.

MATERIAL AND METHOD

Plasma DNA samples were collected from three groups of pregnancies whose fetuses have known thalasemia status (7 normal, 11 heterozygote alpha-thalassemia-1 SEA type deletion, and 7 Bart's hydrops fetalis). The alpha-thalassemia-1 SEA type deletion gene and wild type alpha-globin gene were quantified by using Taqman real-time quantitative PCR and then the delta C(T) was analyzed by subtracting the C(T-mutant) from C(T-wild type).

RESULTS

Mean deltaC(T) values were not significantly different among the three groups. However, women whose fetuses were diagnosed as Bart's hydrops fetalis had a higher proportion (43%) of plasma DNA samples that had negative deltaC(T) value than women whose fetuses were diagnosed as normal or heterozygote alpha-thalassemia-1 SEA type deletion (0 and 27%, respectively).

CONCLUSION

Further investigations are needed to improve the diagnosis of Bart's hydrops fetalis using fetal cell-free DNA.

Comparison of erythrocyte indices to differentiate between iron deficiency and alpha-thalassaemias in children with microcytosis and/or hypochromia

Erythrocyte indices used to differentiate between iron deficiency anaemia (IDA) and thalassaemias have been studied mainly in countries with a high prevalence of IDA or beta-thalassaemias. This study was carried out in the United Arab Emirates where alpha-thalassaemias are prevalent. We studied the predictive value and Youden index of several indices in 85 children aged 6 months to 12 years with microcytosis and/or hypochromia, with or without anaemia (determined by serum measurement of iron or therapeutic iron trial). The best discriminatory indices for detecting IDA versus alpha-thalassaemias were a Green-King index > 65 (correctly identified 75.3% of children, Youden index 44.3) and red cell distribution width >14% (correctly identified 57.8%, Youden index 38.1).

Homozygous alpha-thalassemia-1 presenting in a fetus without anemia

A fetus at risk for alpha-thalassemia presented with cardiomegaly without evidence of anemia. Invasive testing demonstrated the diagnosis of homozygous alpha-thalassemia-1 with a normal-range hemoglobin (Hb) level. We suggest that in the prenatal detection of homozygous alpha-thalassemia-1 by sonography, the diagnosis should always be confirmed with definitive methods such as fetal cord blood Hb analyses. This is important for genetic counseling and treatment for the affected fetus.

Sensitivity and specificity of simple erythrocyte osmotic fragility test for screening of alpha-thalassemia-1 and Beta-thalassemia trait in pregnant women

AIMS

To evaluate the validity of new simple qualitative osmotic fragility test (simple OF) as a screening test in predicting thalassemia trait (alpha-thalassemia-1 and beta-thalassemia).

METHODS

This diagnostic test study was conducted on non-anemic pregnant women attending antenatal care clinic, Maharaj Nakorn Chiang Mai Hospital, during September 2007, and June 2008. Blood samples were collected from 477 singleton pregnancies with no obvious medical complication such as iron deficiency anemia. Simple OF was performed in the same day, using 0.45% glycerin saline solution instead of saline solution. Quantitative HbA2 test and PCR (SEA type) were performed as gold standard to confirm the diagnosis of beta-thalassemia trait and alpha-thalassemia-1 trait, respectively. The main outcome measures included sensitivity, specificity, positive and negative predictive value of simple OF.

RESULTS

The simple OF test had very high sensitivity of 100%, specificity of 73%, positive and negative predictive value of 35, and 100%, respectively.

CONCLUSION

The new simple OF test (using 0.45% glycerin) has high sensitivity in detection of alpha-thalassemia-1 trait or beta-thalassemia trait and due to its simplicity, rapidity, availability and very low cost it may, therefore, be considered as a screening test in a large-scale population.

[Application of mPCR and MLPA in diagnostics of alpha-thalassaemia]

The thalassamias are inherited disorders resulting from unbalanced synthesis of normal polypeptide chains of haemoglobins: of alpha chains in alpha-thalassemia and of beta chains in beta-thalassemia. In Poland, in contrast to beta-thalassaemia, there is no routine diagnostic approach to alpha-thalassaemia. In the present study, for detection of alpha-thalassemia we employed Multiplex-PCR (mPCR) and Multiplex Ligation-dependent Probe Amplification (MPLA). 48 patients with microcytosis and normal or decreased level of haemoglobin HbA2 were examined. In 10 patients three different kinds of deletion mutations in alpha-globin genes were detected: homozygotes and heterozygotes of -alpha(3.7) mutation (-alpha(3.7/-alpha(3.7) and -alpha(3.7)alpha alpha respectively), heterozygotes of Asian mutations (--SEA/alpha alpha), and a heterozygote of Mediterranean mutation (--MED alpha alpha). Our results demonstrate the usefulness of the combined methods of mPCR and MLPA in the diagnostics of alpha-thalassaemia.

Improvement of alpha(0)-thalassemia screening using combined osmotic fragility, dichlorophenolindophenol and Hb H inclusion tests

BACKGROUND

Screening for alpha(0)-thalassemia is usually done using osmotic fragility (OF) test or reduced erythrocyte indexes, both with high sensitivity, but accurate diagnosis requires PCR analysis. However, a low specificity of screening leads to unnecessary PCR workload during a massive population survey. We have established a more effective screening strategy using a combination of three simple tests.

METHODS

The study was done on 206 subjects with hypochromic microcytosis. Methods include osmotic fragility (OF) test, a dichlorophenolindophenol (DCIP) test for Hb E, a modified Hb H inclusion test, Hb and PCR analyses.

RESULTS

Initial screening with combined OF and DCIP tests identified 9 subjects with negative OF and DCIP tests (-/-), 58 with positive OF test but negative DCIP test (+/-), 13 with negative OF but positive DCIP tests (-/+) and 126 subjects with positive in both tests (+/+). Hb H inclusion was observed in 52 of 206 subjects including 1 in OF/DCIP (-/-), 31 in OF/DCIP (+/-) and 20 in OF/DCIP (+/+) groups. Among these 52 subjects, PCR analysis identified alpha(0)-thalassemia in 28 of 31 (+/-) and 16 of 20 (+/+) groups. Five of 106 subjects with negative Hb H inclusion in the (+/+) group were found to be heterozygous (3 of 5) and homozygous (2 of 5) Hb E co-inherited with alpha(0)-thalassemia.

CONCLUSIONS

Hb H inclusion is not an appropriate screening test for alpha(0)-thalassemia in a region where Hb E is common. However performance of the test in the OF/DCIP (+/-) group would enhance the specificity of screening and result in elimination of almost 50% of cases that would have required further PCR confirmation.

Phenotypic presentation and underlying mutations in carriers of β‐thalassaemia and α‐thalassaemia in the Danish immigrant population

OBJECTIVE

The thalassaemia syndromes are the most common hereditary diseases in the world and now appear with relatively high frequency in non-endemic regions. Guidelines recommend the use of mean corpuscular haemoglobin (MCH) alone or in combination with mean corpuscular volume (MCV) in screening for alpha- and beta-thalassaemia. This article deals with the viability of MCV<78 fL alone as screening parameter for thalassaemia in non-endemic regions.

MATERIAL AND METHODS

Data from the Center for Haemoglobinopathies, Herlev University Hospital, consist of MCV measurements from 438 patients with alpha-thalassaemia and 450 patients with beta-thalassaemia referred between 1996 and 2005, and simultaneously measured MCV and MCH measurements in 86 patients referred between November 2004 and November 2005.

RESULTS

In 450 beta-thalassaemia patients and 117 alpha0-thalassaemia patients diagnosed between 1996 and 2005, only two beta-thalassaemia patients had MCV>or=78 fL. All alpha0-thalassaemia patients had MCV<78 fL. In contrast, 38% of patients with alpha+-thalassaemia had MCV>78 fL. When MCV and MCH were measured simultaneously, one patient with beta-thalassaemia was missed if MCV was used as a screening tool and one patient was missed if MCH was used. Forty-four different beta-thalassaemic mutations were found.

CONCLUSIONS

Our data support the notion that the use of MCV<78 fL instead of MCH<27 pg is acceptable as a screening criterion in a non-endemic population. Only 0.5% of the beta-thalassaemia patients were missed and all the patients with alpha0-thalassaemia were diagnosed. Since the racial heterogeneity of the immigrant population in non-endemic regions creates a scenario with a broad spectrum of mutations and haemoglobinopathy, laboratories should be equipped to detect a large variety of mutations.