miR-214 aggravates oxidative stress in thalassemic erythroid cells by targeting ATF4

Oxidative damage to erythroid cells plays a key role in the pathogenesis of thalassemia. The oxidative stress in thalassemia is potentiated by heme, nonheme iron, and free iron produced by the Fenton reaction, due to degradation of the unstable hemoglobin and iron overload. In addition, the levels of antioxidant enzymes and molecules are significantly decreased in erythrocytes in α- and β-thalassemia. The control of oxidative stress in red blood cells (RBCs) is known to be mediated by microRNAs (miRNAs). In erythroid cells, microR-214 (miR-214) has been reported to respond to external oxidative stress. However, the molecular mechanisms underlying this phenomenon remain unclear, especially during thalassemic erythropoiesis. In the present study, to further understand how miR-214 aggravates oxidative stress in thalassemia erythroid cells, we investigated the molecular mechanism of miR-214 and its regulation of the oxidative status in thalassemia erythrocytes. We have reported a biphasic expression of miR-214 in β- and α-thalassemia. In the present study the effect of miR-214 expression was investigated by using miR -inhibitor and -mimic transfection in erythroid cell lines induced by hemin. Our study showed a biphasic expression of miR-214 in β- and α-thalassemia. Subsequently, we examined the effect of miR-214 on erythroid differentiation in thalassemia. Our study reveals the loss-of-function of miR-214 during translational activation of activating transcription factor 4 mRNA, leading to decreased reactive oxygen species levels and increased glutathione levels in thalassemia erythroid cell. Our results suggest that the expression of activating transcription factor 4 regulated by miR-214 is important for oxidative stress modulation in thalassemic erythroid cells. Our findings can help to better understand the molecular mechanism of miRNA and transcription factors in regulation of oxidative status in erythroid cells, particularly in thalassemia, and could be useful for managing and relieving severe anemia symptoms in patients in the future.

Fetal anemia causes placental and maternal cellular damage: a lesson from fetal hemoglobin Bart's disease

INTRODUCTION

The studies about effect of fetal anemia on placental and maternal molecular changes have rarely been published. This study aimed to compare oxidative stress levels and mitochondrial function in the placenta and maternal peripheral blood mononuclear cell (PMBCs) between anemic fetuses (using fetal Hb Bart's disease as a study model) and non-anemic fetuses.

METHODS

A cross-sectional study was conducted on pregnancies affected by Hb Bart's disease and non-anemic fetuses between 16 and 22 weeks of gestation. Placental tissue and maternal blood for PBMCs were collected after pregnancy termination for determination of oxidative stress and mitochondrial function.

RESULTS

A total of 18 pregnancies affected by Hb Bart's disease and 12 non-anemic fetuses were enrolled. Placental thickness was significantly greater (p-value <0.001) in the affected pregnancies, whereas all Doppler indices of uteroplacental blood flow were comparable. Mitochondrial dysfunction was significantly increased (p-value <0.001) in the placenta of the affected fetuses. In the mothers of affected fetuses, there was an increase in mitochondrial oxidative stress levels with a significant increase in mitochondrial dysfunction in isolated PBMCs (p-value <0.001).

DISCUSSION

In the presence of normal uteroplacental Doppler studies, fetal anemia can induce a significant increase in oxidative stress and mitochondrial dysfunction in the placentas and mothers. The findings support that the placenta can be a source of oxidative stress agents which are released into systemic circulation prior to development of maternal adverse outcomes, and may explain pathophysiology of subsequent preeclampsia in late gestation, as commonly seen in pregnancies affected by fetal Hb Bart's disease, if pregnancy is not terminated.

Reduction of extramedullary erythropoiesis and amelioration of anemia in a β-thalassemia patient treated with thalidomide

β-thalassemia patient treated with thalidomide: dimensional reduction of EMH foci (MRI evaluation) and reduction of hematological responce at follow-up.

Fetal hemodynamic changes and mitochondrial dysfunction in myocardium and brain tissues in response to anemia: a lesson from hemoglobin Bart's disease

OBJECTIVE

Whether or not the effects of anemia in the early phase, while the fetuses attempts to increase cardiac output to meet oxygen requirement in peripheral organs, is detrimental to the fetal developing vital organs is little-known. The objective of this is to compare prenatal cardiovascular changes and post-abortal cellular damages in the myocardium as a pumping organ and the brain as a perfused organ between anemic fetuses (using fetal Hb Bart's disease as a study model) in pre-hydropic phase and non-anemic fetuses.

METHODS

Fetuses affected by Hb Bart's disease and non-anemic fetuses at 16-22 weeks were recruited to undergo comprehensive fetal echocardiography. Cord blood analysis was used to confirm the definite diagnosis of fetal Hb Bart's disease and normal fetuses. Fetal cardiac and brain tissues were collected shortly after pregnancy termination for the determination of oxidative stress and mitochondrial function, including mitochondrial ROS production and mitochondrial membrane changes.

RESULTS

A total of 18 fetuses affected by Hb Bart's disease and 13 non-anemic fetuses were recruited. The clinical characteristics of both groups were comparable. The affected fetuses showed a significant increase in cardiac dimensions, cardiac function, cardiac output and brain circulation without deteriorating cardiac contractility and preload. However, in the affected fetuses, mitochondrial dysfunction was clearly demonstrated in brain tissues and in the myocardium, as indicated by a significant increase in the membrane potential change (p-value < 0.001), and a significant increase in ROS production in brain tissues, with a trend to increase in myocardium. The findings indicated cellular damage in spite of good clinical compensation.

CONCLUSION

The new insight is that, in response to fetal anemia, fetal heart increases in size (dilatation) and function to increase cardiac output and blood flow velocity to provide adequate tissue perfusion, especially brain circulation. However, the myocardium and brain showed a significant increase in mitochondrial dysfunction, suggesting cellular damage secondary to anemic hypoxia. The compensatory increase in circulation could not completely prevent subtle brain and heart damage.

Molecular understanding of unusual HbE-β+-thalassemia with Hb phenotype similar to HbE heterozygote: simple and rapid differentiation using HbE levels

BACKGROUND

Low HbF expression in HbE-β+-thalassemia may lead to misdiagnosis of HbE heterozygosity. We aimed to characterize the β- and α-globin genes and the modifying factors related to HbF expression in patients with an Hb phenotype similar to that of HbE heterozygotes. Furthermore, screening tools for differentiating HbE-β+-thalassemia from HbE heterozygotes have been investigated.

PARTICIPANTS AND METHODS

A total of 2133 participants with HbE and HbA with varying HbF levels were recruited. Polymerase chain reaction-based DNA analysis and sequencing were performed to characterize β- and α-globin genes. DNA polymorphism at position -158 nt 5' to Gγ-globin was performed by XmnI restriction digestion. Receiver operating characteristic (ROC) curves were constructed using the area under the curve (AUC). Cutoff values of HbA2, HbE, and HbF levels for the differentiation of HbE-β+-thalassemia from HbE heterozygotes were determined.

RESULTS

Five β+-thalassemia mutations trans to βE-gene (β-87(C>A), β-31(A>G), β-28(A>G), β19(A>G), and β126(T>G)) were identified in 79 patients. Among these, 54 presented with low HbF levels, and 25 presented with high HbF levels. ROC curve analysis revealed an excellent AUC of 1.000 (95% confidence interval:1.000-1.000) for HbE levels, and a cut-off point of ≥35.0% had 100.0% sensitivity, specificity, and Youden's index for differentiating HbE-β+-thalassemia from HbE heterozygotes. The proportion of α-thalassemia mutations was 46.3 and 8.0% among HbE-β+-thalassemia patients with low and high HbF levels, respectively. Two rare α-thalassemia mutations (Cap +14(C>G) and initiation codon (ATG>-TG)) of α2-globin genes were identified. The genotype and allele of the polymorphism at -158 nt 5' to Gγ-globin was found to be negatively associated with HbF expression.

CONCLUSIONS

HbE-β+-thalassemia cannot be disregarded until appropriate DNA analysis is performed, and the detection of α-thalassemia mutations should always be performed under these conditions. An HbE level ≥35.0% may indicate screening of samples for DNA analysis for HbE-β+-thalassemia diagnosis.

Bone Mineral Density and Dickkopf-1 in Adolescents with Non-Deletional Hemoglobin H Disease

BACKGROUND

Low bone mineral density (BMD) is prevalent in individuals with β-thalassemia and is associated with increased circulating dickkopf-1 concentration. These data are limited in α-thalassemia. Therefore, we aimed to determine the prevalence of low BMD and the association between BMD and serum dickkopf-1 in adolescents with non-deletional hemoglobin H disease, a form of α-thalassemia whose severity is comparable to β-thalassemia intermedia.

METHODOLOGY

The lumbar spine and total body BMD were measured and converted into height-adjusted z-scores. Low BMD was defined as BMD z-score ≤ -2. Participant blood was drawn for measurement of dickkopf-1 and bone turnover marker concentrations.

RESULTS

Thirty-seven participants with non-deletional hemoglobin H disease (59% female, mean age 14.6 ± 3.2 years, 86% Tanner stage ≥2, 95% regularly transfused, 16% taking prednisolone) were included. Over one year prior to the study, mean average pretransfusion hemoglobin, ferritin and 25-hydroxyvitamin D concentrations were 8.8 ± 1.0 g/dL, and 958 ± 513 and 26 ± 6 ng/mL, respectively. When participants taking prednisolone were excluded, the prevalence of low BMD at the lumbar spine and total body was 42% and 17%, respectively. BMD at both sites was correlated positively with body mass index z-score, and negatively with dickkopf-1 (all p-values <0.05). There were no correlations among dickkopf-1, 25-hydroxyvitamin D, osteocalcin and C-telopeptide of type-I collagen. Multiple regression analysis showed dickkopf-1 inversely associated with total body BMD z-score adjusting for sex, bone age, body mass index, pre-transfusion hemoglobin, 25-hydroxyvitamin D, history of delayed puberty, type of iron chelator and prednisolone use (p-value = 0.009).

CONCLUSIONS

We demonstrated a high prevalence of low BMD in adolescents with non-deletional hemoglobin H disease. Moreover, dickkopf-1 inversely associated with total body BMD suggesting it may serve as a bone biomarker in this patient population.

Fetal Hemodynamic Response to Anemia in Early Gestation: Using Hemoglobin Bart's Disease as a Study Model

OBJECTIVE

 To assess fetal hemodynamic changes in response to anemia in early gestation, using fetal Hb Bart's disease as a study model.

METHODS

 A prospective study was conducted on pregnancies at risk for fetal Hb Bart's disease at 12-14 weeks of gestation. Fetal hemodynamics were comprehensively assessed by 2D ultrasound, Doppler velocity, and cardio-STIC just prior to the invasive procedure for diagnosis. The various hemodynamic parameters of the affected and unaffected fetuses were compared.

RESULTS

 Of 56 fetuses at risk, 17 had Hb Bart's disease and 39 were unaffected. The right and combined ventricular cardiac outputs (CO) were significantly higher in the affected fetuses (0.993 vs. 1.358; p < 0.001 and 1.010 vs. 1.236; p < 0.001, respectively), whereas the left CO tended to be higher but not significantly (1.027 vs. 1.113; p = 0.058). Cardiac dimensions, middle-cerebral artery peak systolic velocity, Tei index, and isovolemic contraction time were significantly increased, while the global sphericity index was significantly decreased. Interestingly, cardiac preload, ventricular wall thickness, shortening fraction, isovolemic relaxation time, and fetal heart rate were unchanged. Four fetuses had hydropic changes, but all cardiac functions were normal.

CONCLUSION

 Fetal anemia induces hypervolemia and increases cardiac output to meet the tissue oxygen requirement, resulting in an increase in size without hypertrophy, volume load without pressure load, and a decrease in the globular sphericity index. The heart works very well but works harder, especially systolic ventricular load. Hydrops fetalis due to anemia appears not to be caused by heart failure as previously believed but rather by volume load with high vascular permeability at least in early pregnancy.

The continuing global challenges of treating patients with beta‐thalassemia

In this issue, Hokland et al. offer an interesting view of the different approaches on how to treat a beta-thalassemia patient. The principal concerns, that this report reveals, are the very wide differences in the facilities and economic resources available for the care of patients. Management of thalassemia should become a word wide health care priority and may include at last those two steps: national and international registries; national programs for screening couples at risk and providing preventive measures to prevent births of patients with thalassemia. Commentary on: Hokland et al. Thalassaemia-A global view. Br J Haematol. 2023;201:208-223.

Colorectal cancer patient-derived organoids and cell lines harboring ATRX and/or DAXX mutations lack Alternative Lengthening of Telomeres (ALT)

Telomere maintenance is necessary to maintain cancer cell unlimited viability. However, the mechanisms maintaining telomere length in colorectal cancer (CRC) have not been extensively investigated. Telomere maintenance mechanisms (TMM) include the re-expression of telomerase or alternative lengthening of telomeres (ALT). ALT is genetically associated with somatic alterations in alpha-thalassemia/mental retardation X-linked (ATRX) and death domain-associated protein (DAXX) genes. Cells displaying ALT present distinctive features including C-circles made of telomeric DNA, long and heterogenous telomeric tracts, and telomeric DNA co-localized with promyelocytic leukemia (PML) bodies forming so-called ALT-associated PML bodies (APBs). Here, we identified mutations in ATRX and/or DAXX genes in an extensive collection of CRC samples including 119 patient-derived organoids (PDOs) and 232 established CRC cell lines. C-circles measured in CRC PDOs and cell lines showed low levels overall. We also observed that CRC PDOs and cell lines did not display a significant accumulation of APBs or long telomeres with no appreciable differences between wild-type and mutated ATRX/DAXX samples. Overall, our extensive analyses indicate that CRC is not prone to engage ALT, even when carrying genetic lesions in ATRX and/or DAXX, and support the notion that ATRX/DAXX genomic footprints are not reliable predictors of ALT.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Thalassemia Intermedia: Chelator or Not?

Thalassemia is the most common genetic disorder worldwide. Thalassemia intermedia (TI) is non-transfusion-dependent thalassemia (NTDT), which includes β-TI hemoglobin, E/β-thalassemia and hemoglobin H (HbH) disease. Due to the availability of iron chelation therapy, the life expectancy of thalassemia major (TM) patients is now close to that of TI patients. Iron overload is noted in TI due to the increasing iron absorption from the intestine. Questions are raised regarding the relationship between iron chelation therapy and decreased patient morbidity/mortality, as well as the starting threshold for chelation therapy. Searching all the available articles up to 12 August 2022, iron-chelation-related TI was reviewed. In addition to splenectomized patients, osteoporosis was the most common morbidity among TI cases. Most study designs related to ferritin level and morbidities were cross-sectional and most were from the same Italian study groups. Intervention studies of iron chelation therapy included a subgroup of TI that required regular transfusion. Liver iron concentration (LIC) ≥ 5 mg/g/dw measured by MRI and ferritin level > 300 ng/mL were suggested as indicators to start iron chelation therapy, and iron chelation therapy was suggested to be stopped at a ferritin level ≤ 300 ng/mL. No studies showed improved overall survival rates by iron chelation therapy. TI morbidities and mortalities cannot be explained by iron overload alone. Hypoxemia and hemolysis may play a role. Head-to-head studies comparing different treatment methods, including hydroxyurea, fetal hemoglobin-inducing agents, hypertransfusion as well as iron chelation therapy are needed for TI, hopefully separating β-TI and HbH disease. In addition, the target hemoglobin level should be determined for β-TI and HbH disease.

The chromatin remodeling protein ATRX positively regulates IRF3-dependent type I interferon production and interferon-induced gene expression

The chromatin remodeling protein alpha thalassemia/mental retardation syndrome X-linked (ATRX) is a component of promyelocytic leukemia nuclear bodies (PML-NBs) and thereby mediates intrinsic immunity against several viruses including human cytomegalovirus (HCMV). As a consequence, viruses have evolved different mechanisms to antagonize ATRX, such as displacement from PML-NBs or degradation. Here, we show that depletion of ATRX results in an overall impaired antiviral state by decreasing transcription and subsequent secretion of type I IFNs, which is followed by reduced expression of interferon-stimulated genes (ISGs). ATRX interacts with the transcription factor interferon regulatory factor 3 (IRF3) and associates with the IFN-β promoter to facilitate transcription. Furthermore, whole transcriptome sequencing revealed that ATRX is required for efficient IFN-induced expression of a distinct set of ISGs. Mechanistically, we found that ATRX positively modulates chromatin accessibility specifically upon IFN signaling, thereby affecting promoter regions with recognition motifs for AP-1 family transcription factors. In summary, our study uncovers a novel co-activating function of the chromatin remodeling factor ATRX in innate immunity that regulates chromatin accessibility and subsequent transcription of interferons and ISGs. Consequently, ATRX antagonization by viral proteins and ATRX mutations in tumors represent important strategies to broadly compromise both intrinsic and innate immune responses.

ATRX is a member of a family of chromatin remodeling proteins required for deposition of the histone variant H3.3 at specific genomic regions. This is important to maintain silencing at these sites. Furthermore, ATRX represents a component of PML nuclear bodies (PML-NBs) which are considered as enigmatic nuclear protein accumulations exhibiting a tight link to cell-intrinsic restriction of viral infections. Previous studies demonstrated that many viruses target ATRX by either displacement or degradation. So far, it is believed that this serves to alleviate ATRX-instituted silencing of viral gene expression. Our results reveal a novel and unexpectedly broad function of ATRX as a co-activator of the innate immune response. We show that ATRX is required for both DNA and RNA sensing pathways to activate interferon (IFN) gene expression as well as for upregulation of a distinct set of interferon-stimulated genes. Assessment of chromatin accessibility detected that IFN acts as a switch to regulate the function of ATRX in heterochromatin remodeling. ATRX positively modulates chromatin accessibility specifically upon IFN signaling, thereby affecting promoter regions with recognition motifs for AP-1 family transcription factors. Loss of ATRX due to viral infection or due to tumor mutations may thus broadly compromise cellular innate immunity.

ATRX protein is a potential prognostic marker in clear cell renal cell carcinoma

OBJECTIVE

Cancer cells activate either telomerase or alternative lengthening of telomeres (ALT) to maintain telomere length and achieve immortalization. Alpha thalassemia/mental retardation X-linked (ATRX) is involved in chromatin remodeling. Mutations in ATRX genes are associated with the loss of nuclear expression and correlated with the ALT phenotype. ATRX expression has been evaluated in various cancers, especially sarcoma and neuroendocrine tumors, and its clinical significance has been shown to be diverse, depending on the tumor types. The role and prognostic value of ATRX expression in clear cell renal cell carcinoma (CCRCC) have not been elucidated.

METHODS

We investigated the messenger RNA (mRNA) expression levels of ATRX using the gene expression profiling interactive analysis (GEPIA) database and evaluated the expression of ATRX using immunohistochemical (IHC) staining in 302 CCRCC cases.

RESULTS

Loss of ATRX expression was significantly associated with larger tumor size, higher nuclear grade (NG), lymphovascular invasion (LVI), pathologic T (pT) stage, recurrence/metastasis, and stage. Although ATRX was not an independent prognostic factor, patients with loss of ATRX expression showed poor survival.

CONCLUSION

Our findings suggest that loss of ATRX expression could be a potential biomarker for predicting aggressive tumor behavior and poor clinical outcomes in CCRCC.

[The value of combined detection of HbA2 and HbF for the screening of thalassemia among individuals of childbearing ages]

OBJECTIVE

To assess the application value of combined detection of HbA2 and HbF for the screening of thalassemia among a population of childbearing age in Quanzhou, Fujian, and determine the optimal cut-off values for the region.

METHODS

Capillary hemoglobin electrophoresis and genetic testing for α and β globin gene mutations were simultaneously carried out on 11 428 patients with suspected thalassemia. Statistical methods were used to analyze the distribution of various types of thalassemia and compare the performance of HbA2 and HbF measurement for the screening of various types of thalassemia. The optimal cut-off values for HbA2 and HbF were determined with the ROC curves.

RESULTS

4591 patients with α, β, and αβ compound thalassemia were identified by genetic testing. The most common genotypes for α and β thalassemia included --SEA/αα and β654/βN, β41-42/βN, and β17/βN. The ROC curves were drawn to compare the performance of HbA2 screening for α-, β-, αβ-compound, static α-, mild α-, and intermediate α-thalassemia, and the maximum area under the curves was 0.674, 0.984, 0.936, 0.499, 0.731, 0.956, and the optimal cut-off values for HbA2 were 2.45%, 3.25%, 3.65%, 2.95%, 2.55%, 1.75%, respectively.

CONCLUSION

HbA2 is an efficient indicator for identifying intermediate types of α-, β-, and αβ compound thalassemia. The combination of HbA2 and HbF measurement can effectively detect carriers for β-thalassemia mutations.

Amniotic fluid metabolomic and lipidomic alterations associated with hemoglobin Bart's diseases

INTRODUCTION

α-Thalassemia is the most common inherited disease in southern China. The severest form is hemoglobin (Hb) Bart's disease, in which the affected fetuses almost always die in utero or shortly after birth, and the mothers are at high risk for severe morbidity.

OBJECTIVE

To investigate the changes in all metabolites in fetuses with Hb Bart's disease and to characterize the metabolomic and lipidomic biomarkers in the development of Hb Bart's fetuses.

METHODS

Amniotic fluid (AF) specimens were selected from 34 pregnant women who underwent interventional prenatal diagnosis from June 2017 to June 2018. Gap-PCR analysis was used to diagnose Hb Bart's disease, and untargeted metabolomic and lipidomic analyses were performed.

RESULTS

By analyzing AF samples, 935 differential metabolites were selected between Hb Bart's and control fetuses. The metabolites with significant changes mainly involved D-glutamine and D-glutamate metabolism, histidine metabolism, arginine metabolism, beta-alanine metabolism and alanine, aspartate and glutamate metabolism. Further lipidomics analysis revealed 132 differential lipids, mainly involved phosphatidylcholine and triglyceride metabolism. Through the characterized metabolites in AF, a schematic model of Hb Bart's disease was established.

CONCLUSION

Glutamate and glutathione metabolism, aspartate metabolism, urea metabolism and triglyceride metabolism were significantly changed in the Hb Bart's group compared to the control group. The characterized biomarkers were mainly involved in oxidative stress reaction, iron overload and liver dysfunction. This finding may help improve the treatment options for α-thalassemia as well as diagnosing phenotype of patients.

Misleading HbA1c Measurement in Diabetic Patients with Hemoglobin Variants

BACKGROUND AND OBJECTIVES

Hemoglobin A1c (HbA1c) is widely used for the monitoring and management of diabetes mellitus. The aim of this study is to investigate the influence of hemoglobin (Hb) variants on the measurement of HbA1c.

MATERIALS AND METHODS

HbA1c levels of 845 blood samples obtained from diabetic patients with various hemoglobin types were measured using a turbidimetric inhibition immunoassay and capillary electrophoresis.

RESULTS

Of 845 patients with diabetes, 65.7% (555/845) have the normal hemoglobin type (A₂A) and 34.3% (290/845) have various abnormal hemoglobin types, including heterozygous HbE 30.2% (255/845), homozygous HbE 1.9 % (16/845), Hb Constant Spring (CS) trait 1.4% (12/845), CSEA Bart's 0.2% (2/845), and beta-thalassemia trait 0.6% (5/845). In most of the patients with diabetes, HbA1c levels determined by two different methods, inhibition immunoassay and capillary electrophoresis, gave strong positive correlation (R = 0.901, P < 0.001), except for those with homozygous HbE (N = 16) and CSEA Bart's (N = 2). In all 18 patients with homozygous HbE and CSEA Bart's, the HbA1c was undetectable by capillary electrophoresis, meaning that their estimated average glucose was undeterminable, although their HbA1c levels could be measured using an inhibition immunoassay. The discrepancy of HbA1c results obtained from two different methods is noted in patients without HbA.

CONCLUSIONS

We have demonstrated the erroneous nature of HbA1c measurement in patients with hemoglobin variants, especially in those without HbA expression. Therefore, in the population with a high prevalence of hemoglobinopathies, hemoglobin typing should be considered as basic information prior to HbA1c measurement.

Siriraj I Gγ(Aγδβ)0-thalassaemia causing severe thalassaemia intermedia in compound heterozygous state with IVS1-1(G→T) mutation

The Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia is a novel mutation involving a 118kb deletion of the β-globin gene cluster. It was first reported in 2012 in two unrelated families from the southern part of Thailand. The carriers in the heterozygous state are clinically asymptomatic. Nonetheless, its complex interaction with other β-thalassaemia could give rise to different clinical phenotypes, ranging from mild thalassaemia intermedia to thalassaemia major. We report here a case of a six-year-old Malay boy, presented with pallor, growth failure and hepatosplenomegaly. His haemoglobin at presentation was 9.2g/dL with a mean cell haemoglobin of 22.6pg and a mean cell volume of 69.9fl. His peripheral blood smear showed features of thalassaemia intermedia. Haemoglobin (Hb) analysis revealed markedly raised Hb F (83%), normal HbA2 levels and absent HbA. Deoxyribonucleic acid (DNA) analysis showed compound heterozygous IVS1-1 (G→T) β-globin gene mutation and Siriraj I ^Gγ(^Aγδβ)⁰-deletion (genotype β^IVS1-1/ β ^{Siriraj I deletion}). Both his father and elder sister are carriers of Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia while his mother carries IVS1-1 (G→T) gene mutation. Clinically, the patient is transfusion dependent on six weekly regime. To the best of our knowledge, this is the first reported case in Malaysia involving unique Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia and IVS1-1 (G→T) in a compound heterozygous state. In summary, detection of Siriraj I ^Gγ(^Aγδβ)⁰-thalassaemia is essential as this deletion can lead to severe disease upon interaction with a β-thalassemia point mutation as demonstrated in our case. The establishment of effective carrier screening and genetic counselling is important to prevent its adverse consequences.

[Effect of high-throughput sequencing for the prevention and control of thalassemia]

OBJECTIVE

To assess the value of next generation sequencing (NGS) for the prevention and control of thalassemia.

METHODS

NGS was used to sequence 3083 clinical blood samples suspected for thalassemia during initial screening. Retrospective analysis was conducted on blood samples detected with rare genotypes of thalassemia and abnormal hemoglobin.

RESULTS

NGS analysis of the 3083 samples has found 1089 subjects with thalassemia genotypes (alpha-thelassemia genotype: 26.01%, beta-thalassemia genotype: 6.71%, and alpha-compound-beta genotype: 2.59%), which yielded a positive detection rate of 35.32%. Rare alpha-thalassemia genotypes including HBA2 c.123delG, HBA1 c.354_355insATC and Fusion gene, and rare beta-thalassemia genotypes including HBB c.-100G>A and HBB c.316-90A>G, were discovered. In addition, 19 patients were found to have abnormal hemoglobin, mainly including Hb Hamilton, Hb Hekinan II, Hb Shizuoka, Hb Owari, Hb New York, Hb J-Bangkok and Hb Port Phillip.

CONCLUSION

NGS can play a crucial role for improving of the prevention and control of thalassemia and formulating a screening system with better efficacy.

[Gene characteristics and changing trend of neonatal thalassemia in Dongguan, China]

OBJECTIVE

To study the gene distribution characteristics of neonatal thalassemia in Dongguan, China and the changing trend of the gene distribution characteristics of neonates with thalassemia in Dongguan in 2014-2018.

METHODS

A retrospective analysis was performed for the data on neonatal thalassemia screening from the Dongguan Neonatal Disease Screening System between January 2014 and December 2018. A total of 616 718 neonates were enrolled who were born in Dongguan.

RESULTS

Among the 616 718 neonates, 52 308 were positive for primary screening, 10 366 were recalled, 8 576 underwent genetic diagnosis, and 6 432 were confirmed with thalassemia by genetic diagnosis. The carrying rates of thalassemia genes in 2014-2018 were 5.81%, 5.47%, 5.96%, 6.91%, and 7.90% respectively, and showed an upward trend (P<0.001). The positive rates of neonatal thalassemia screening in 2014-2018 were 9.12%, 8.34%, 7.54%, 8.13%, and 9.32% respectively (P<0.001). The positive rates of genetic diagnosis of neonatal thalassemia in 2014-2018 were 0.89%, 1.11%, 1.24%, 0.90%, and 1.09% respectively (P<0.001). In 2014-2018, 5 098 cases of α-thalassemia were detected, accounting for 79.26% of all cases, and 1 230 cases of β-thalassemia were detected, accounting for 19.12% of all cases. The detection rate of α-thalassemia was significantly higher than that of β-thalassemia in each year (P<0.001). In 2014-2018, static α-thalassemia, mild α-thalassemia, and mild β-thalassemia were the main types observed in neonates.

CONCLUSIONS

Most of the neonates with thalassemia have α-thalassemia in Dongguan, with static α-thalassemia and mild α-thalassemia as the main types. The carrying rate of thalassemia genes keeps increasing in neonates in Dongguan, and the prevention and treatment of thalassemia is still challenging.

Alpha-Thalassemia Carrier due to -α3.7 Deletion: Not So Silent

BACKGROUND/OBJECTIVE

Alpha-thalassemia is one of the most prevalent genetic diseases, with the -α3.7 deletion being the most common mutation. Molecular studies have suggested mechanisms to explain the mild phenotype of "silent carrier" heterozygotes. However, the correlation between the clinical laboratory picture and the -α3.7 heterozygous state remains unclear, thus we chose to investigate.

METHODS

We analyzed the medical files of 192 children evaluated for microcytosis at our tertiary center between 2007 and 2017 and diagnosed as heterozygotes for the -α3.7 deletion. Additional α-thalassemia mutations, iron deficiency anemia, and β-thalassemia were ruled out. Laboratory parameters were compared to age- and sex-matched reference values.

RESULTS

The -α3.7 carriers had significantly lower Hb and mean corpuscular volume (MCV) than the reference population, and significantly higher red blood cell counts across all age groups. The greatest reduction in Hb level appeared among male adolescents, while MCV was consistently 2 SDs lower than normal in most patients older than 2 years.

CONCLUSION

Heterozygosity for the -α3.7 deletion was associated with clinically significant microcytosis and mild anemia in our pediatric population. In the absence of iron deficiency and β-thalassemia, this finding provides a diagnosis for mild microcytic anemia, making additional investigations of microcytosis unnecessary.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Molecular Diagnostics of Gliomas Using Next Generation Sequencing of a Glioma-Tailored Gene Panel

Current classification of gliomas is based on histological criteria according to the World Health Organization (WHO) classification of tumors of the central nervous system. Over the past years, characteristic genetic profiles have been identified in various glioma types. These can refine tumor diagnostics and provide important prognostic and predictive information. We report on the establishment and validation of gene panel next generation sequencing (NGS) for the molecular diagnostics of gliomas. We designed a glioma-tailored gene panel covering 660 amplicons derived from 20 genes frequently aberrant in different glioma types. Sensitivity and specificity of glioma gene panel NGS for detection of DNA sequence variants and copy number changes were validated by single gene analyses. NGS-based mutation detection was optimized for application on formalin-fixed paraffin-embedded tissue specimens including small stereotactic biopsy samples. NGS data obtained in a retrospective analysis of 121 gliomas allowed for their molecular classification into distinct biological groups, including (i) isocitrate dehydrogenase gene (IDH) 1 or 2 mutant astrocytic gliomas with frequent α-thalassemia/mental retardation syndrome X-linked (ATRX) and tumor protein p53 (TP53) gene mutations, (ii) IDH mutant oligodendroglial tumors with 1p/19q codeletion, telomerase reverse transcriptase (TERT) promoter mutation and frequent Drosophila homolog of capicua (CIC) gene mutation, as well as (iii) IDH wildtype glioblastomas with frequent TERT promoter mutation, phosphatase and tensin homolog (PTEN) mutation and/or epidermal growth factor receptor (EGFR) amplification. Oligoastrocytic gliomas were genetically assigned to either of these groups. Our findings implicate gene panel NGS as a promising diagnostic technique that may facilitate integrated histological and molecular glioma classification.

Distribution of alpha thalassaemia in 16 year old Malaysian Students in Penang, Melaka and Sabah

OBJECTIVES

Alpha thalassaemia is wide spread in Malaysia and is a public health problem. This study aimed to describe the carrier frequencies of α‒thalassaemia and its distribution among major ethnic groups in three states of Malaysia.

METHODS

Educational forums were organised and study was explained to students from three schools. Students were invited to take part in the screening with parent consent. A total of 8420 adolescent students aged 16 years volunteered to participate in the study. Peripheral blood samples were analysed for complete blood counts, haemoglobin quantification and typing, and serum ferritin levels. Genomic DNA was used for screening alpha thalassaemia alleles by PCR based molecular methods.

RESULTS

We identified seven α‒globin gene defects in 341 (4.08%) students: amongst them α(+)‒ and α(0)‒thalassaemias were detected in 232 (2.77%) and 107 (1.28%) students respectively. Genotype ‒α(3.7)/αα was the most prevalent among sub-populations of Malay, indigenous communities of Sahab and Indian, while ‒‒(SEA)/αα deletion is more prevalent in Malaysian Chinese. It is estimated that 63 pregnancies annually are at risk of Hb Bart's hydrops fetalis.

CONCLUSIONS

We have demonstrated the prevalence and mutation patterns of α‒thalassaemia in the 16 year olds in three states of Malaysia. High α(0)‒thalassaemia deletions amongst the study subjects place these carriers at an increased risk of conceiving fetuses with HbH disease and Hb Bart's hydrops fetalis should they choose another heterozygous partner. It is therefore highly recommended to institute community screening programmes and provide prospective carriers with genetic counselling to help them make informed choices.

[Diagnosis of persistent left superior vena cava in a child using transesophageal echocardiography]

An 11-year-old boy with X-linked alpha-thalassaemia/ mental retardation symptom underwent gastrostomy. After the surgical procedure, insertion of a central venous (CV) catheter via the left subclavian vein was performed under X-ray radioscopy. However, the catheter did not move toward the right side of the heart shadow but descended caudally through the left side of the heart shadow. Transesophageal echocardiography (TEE) showed thickening of the coronary sinus, suggesting the existence of a persistent left superior vena cava (PLSVC). Contrast echocardiography using infusion of agitated saline into the CV catheter was performed. Microbubbles flowing from the coronary sinus into the right atrium were observed, and a diagnosis of PLSVC was made. TEE is useful for diagnosis of PLSVC when passage of a CV catheter via the left subclavian vein or left internal jugular vein is incorrect in a pediatric patient.

Hemoglobin variants and disease manifestations in severe falciparum malaria

CONTEXT

The geographical distributions of hemoglobin S (HbS), hemoglobin C (HbC), and alpha+-thalassemia (-alpha) strongly suggest balancing selection with malaria. However, whereas several studies indicate that the HbS carrier state protects against all major forms of clinical malaria, malaria protection on clinical grounds has been more difficult to confirm for HbC and -alpha, and questions remain as to whether it applies to all forms of the disease.

OBJECTIVE

To assess the association between major clinical forms of severe falciparum malaria and HbS, HbC, and -alpha.

DESIGN, SETTING, AND PARTICIPANTS

Case-control study of 2591 children with severe falciparum malaria enrolled at a tertiary referral center in Ghana, West Africa, and 2048 age-, sex-, and ethnicity-matched control participants recruited by community surveys.

MAIN OUTCOME MEASURES

Frequencies of HbS, HbC, and -alpha in patients and controls, including stratifications of patients for signs of disease.

RESULTS

Patients presented with partly overlapping signs of disease, including severe anemia (64%), cerebral malaria (22%), respiratory distress (30%), hyperparasitemia (32%), prostration (52%), acidosis (59%), and hyperlactatemia (56%). Carrier states of HbS, HbC, and -alpha were found in 1.4%, 9.4%, and 25.2% of the patients, respectively, and 14.8%, 8.7%, and 27.3% of controls. The HbS carrier state was negatively associated with all forms of the disease studied (overall odds ratio [OR], 0.08; 95% confidence interval [CI], 0.06-0.12). The HbC carrier state showed a negative association selectively with cerebral malaria (OR, 0.64; 95% CI, 0.45-0.91), and the -alpha carrier state showed a negative association selectively with severe anemia (OR, 0.82; 95% CI, 0.69-0.96).

CONCLUSION

Whereas the HbS carrier state was found to be negatively associated with all major forms of severe falciparum malaria, the negative associations of the carrier states of HbC and -alpha appeared to be limited to cerebral malaria and severe anemia, respectively.

Genetic benefits of consanguinity through selection of genotypes protective against malaria

Consanguineous marriages are usually socially driven and can be genetically harmful. The detrimental effects of inbreeding are the consequence of homozygosity of harmful genes. On the other hand, beneficial effects of inbreeding, theoretically, could be expected in those who are homozygous for protective recessive and codominant genes. Here, we argue that the most common monogenetic conditions in humans, namely, alpha-thalassemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency, hemoglobin C, and Duffy antigen negative red blood cells, which have evolved under pressure from malaria, had their survival and selection enhanced by consanguineous marriages in malaria-infested regions of the world. This hypothesis is supported by several observations. First, the presence of two mutations in homozygotes involving the listed conditions (except G6PD deficiency) imparts better protection against malaria than the presence of one or no mutation (heterozygous or normal genotypes, respectively); consanguinity increases the number of homozygotes, especially at low allele frequency. For G6PD deficiency, inbreeding could increase the allele frequency of the G6PD-deficient allele. Second, there is overlap between, on the one hand, the geographic distributions of malaria, thalassemias, and other red blood cell conditions that protect against malaria and, on the other hand, consanguineous marriages. Third, the distribution of different intensities of malaria infestation is matched with the frequency of human inbreeding. These observations, taken together, offer strong support to the hypothesis that the culture of consanguineous marriages and the genetics of protection against malaria have co-evolved by fostering survival against malaria through better retention of protective genes in the extended family.

Hyperbilirubinemia and cholelithiasis in Chinese patients with hemoglobin H disease

Hemoglobin H disease (HbH) is a hemoglobinopathy peculiar to parts of the world with high incidence alpha-thalassemia mutations. Among 90 HbH cases, 50 cases suffered from clinically significant jaundice (bilirubin >30 mmol/l), including 14 with severe jaundice (bilirubin >60 mmol/l). Cholelithiasis was found in 38 cases. The incidence is roughly eight times higher than that in background control population but 50% lower than that in beta-thalassemia. The risk of gallstones was related to higher bilirubin levels but not alpha-globin genotype, sex, ferritin, and hemoglobin levels. Homozygotes or double heterozygotes for Gilbert alleles (17.2%), but not heterozgyotes (42.2%), were found to have a significantly increased risk of gallstones and jaundice. However, common Chinese Gilbert syndrome alleles do not completely explain the variable risks.

New Strategies in the Treatment of the Thalassemias

In addition to the severe beta thalassemias, hematologists have begun to recognize the more severe forms of alpha thalassemia, namely hemoglobin (Hb) H disease and Hb H/Hb Constant Spring, as well as the beta compound heterozygote, beta thalassemia/HbE. Clinically, variably severe anemia becomes apparent in the first year accompanied by occasionally massive expansion of erythropoiesis. The most anemic patients require regular red blood cell transfusions to avoid death from cardiac failure. However, the inevitable iron accumulation leads to dysfunction, primarily involving the heart, liver, and endocrine system; thus, regularly transfused patients require iron chelation. A major discovery was that allogeneic bone marrow (stem cell) transplantation in severely affected subjects with both alpha and beta thalassemia could result in cure. Current work deals with specific complications, such as iron overload and endocrine, cardiopulmonary, thrombophilic, and osteopenic problems. The thalassemias are likely to benefit in the future from specific gene therapy. There are also important advances in genetic counseling based on results of early fetal diagnosis.

Flow cytometric quantitation of red blood cell vesicles in thalassemia

BACKGROUND

Thalassemia is a hereditary hemolytic anemia caused by mutations in the globin gene complex. Circulatory disturbances including arterial and venous thrombosis have also been noted in these patients. Aggregability of abnormal RBC and the high level of membrane-derived microparticles stemming from activated platelets and other blood cells are thought to be responsible for the associated thrombotic risk. Destruction of RBC is also thought to be an important pathophysiological consequence, particularly through the formation of circulating vesicles. To our knowledge, there has been no attempt to quantitatively evaluate the number of RBC vesicles in thalassemia. This prompted us to study the level of RBC vesicles in the peripheral blood of thalassemia patients using quantitative flow cytometry.

METHODS

Whole blood from each subject was doubly stained for RBC and platelet or annexin V markers, together with the known density TruCount beads. RBC vesicles were gated according to their forward/side scatter and RBC marker. Percentage of RBC vesicles and their absolute number were analyzed by flow cytometry.

RESULTS

Our data indicated that RBC vesicles were annexin V-positive. The number of annexin V-positive events was higher than their intact RBCs. RBC vesicles were present in both normal and thalassemic blood samples, but the numbers of RBC vesicles were significantly higher in thalassemia. Both the percentage and the absolute number of RBC vesicles were especially marked in splenectomized subjects with beta-thalassemia/Hemoglobin E. When clinical and hematological indices were compared with RBC vesicles, there was an inverse relationship between the degree of severity in thalassemia patients and the number of RBC vesicles.

CONCLUSION

Flow cytometric quantitation of RBC vesicles is simple, reliable and may offer new insights in to study of the relationship between defective hemoglobin synthesis, RBC perturbation and pathophysiological complications in thalassemia.

Alpha Thalassemia is associated with decreased risk of abnormal transcranial Doppler ultrasonography in children with sickle cell anemia

PURPOSE

Cerebrovascular complications of sickle cell disease (SCD) are common, but the risk factors remain unclear. The multicenter Stroke Prevention Trial in Sickle Cell Anemia (STOP) provided an opportunity to examine alpha thalassemia-2 as a modifying risk factor, using abnormal transcranial Doppler ultrasonography (TCD) as a surrogate marker for cerebrovascular disease. The authors hypothesized that children with abnormal TCD are less likely to have alpha thalassemia-2, and an increased hemoglobin level accounts for this protective effect.

METHODS

A retrospective study was conducted of children with SCD who had both alpha gene and TCD data from STOP: 128 with TCD of at least 200 cm/s (abnormal TCD) and 172 with TCD less than 170 cm/s (normal TCD).

RESULTS

Alpha thalassemia-2 was more frequent in the normal TCD group compared with the abnormal TCD group. The odds ratio for normal TCD and alpha thalassemia-2 was 4.1. Adjusting for either hemoglobin level or red cell size (mean corpuscular volume) reduced the odds ratio only slightly. Age, normal TCD, and alpha thalassemia-2 had significant statistical interaction, so that alpha thalassemia-2 was not related to TCD for age 10 years or older.

CONCLUSIONS

The frequency of alpha thalassemia-2 was significantly higher in children with normal TCD. Speculation on mechanisms of effect includes improved erythrocyte deformability, reduced red cell adhesion, and reduced nitric oxide scavenging in alpha thalassemia-2. The association of alpha thalassemia-2 and normal TCD adds to the evidence on the protective effects of alpha thalassemia-2 in SCD and highlights the contribution of epistatic factors.

[Congenital hemolytic anemia--hemoglobin abnormality--thalassemia]

Thalassemias are a group of genetic disorders caused by unbalanced synthesis of alpha- and non-alpha chains of globins due to impaired globin genes. Clinical characteristics of the thalassemias are ineffective erythropoiesis and hemolytic anemia with microcytic-hypochromic erythrocytes. Surplus polypeptide chain synthesized by normal globin gene causes harmful effects to skeleton proteins of erythrocyte membrane, such as spectrin, ankirin and 4.1 protein, via a few different ways and normal integrity of membrane is disturbed. Basic mechanism of pathophysiology of thalassemias have been made clear but many problems remain to be overcame in clinical practice. Several methodological improvements in diagnosis have been coming out using DNA amplification technique and applied to prenatal diagnosis and mass-screening of thalassemias. In therapeutic methods, little improvement has been observed for last decade since introduction of bone marrow transplantation.

Preimplantation diagnosis of alpha-thalassemia by blastomere aspiration and polymerase chain reaction: preliminary experience

The ability to diagnose and detect the presence of debilitating and life-threatening diseases would be an invaluable asset to those involved in in vitro fertilization programs. To investigate the possibility of diagnosing severe alpha-thalassemia before implantation, DNA sequences targeting the abnormal deletion breakpoint and the normal region of the alpha-globin gene were amplified by polymerase chain reaction from blastomeres aspirated from human preimplantation embryos. Before performing this experiment, a mouse model blastomere aspiration technique was examined to confirm embryo survival and normal development capability. The mouse embryos showed undisturbed development in the five- to seven-, as well as the eight-cell stages when one, or two (eight-cell stage only) blastomeres were aspirated. The four-cell embryos had a lower survival rate but had a blastocyst formation rate comparable to the more advanced stages and the control embryos. In the human embryo experiment, no homozygous Southeast Asian alpha-thalassemia was detected in the aspirated blastomeres, although two heterozygotic alpha-thalassemia embryos were discovered. The sensitivities of targeting sequence detection in the mouse and human blastomeres were between 50% and 76% in the respective groups. This study supports the feasibility of preimplantation diagnosis of severe alpha-thalassemia when both father and mother are carriers of this inheritable disease.