The prevalence of thalassemia in mainland China: evidence from epidemiological surveys

Detection of α-thalassemia South-East Asian deletion based on a fully integrated digital polymerase chain reaction system DropXpert S6

OBJECTIVES

This study aimed to establish a droplet digital polymerase chain reaction (ddPCR) assay for South-East Asian (SEA) deletion based on a fully integrated digital PCR system DropXpert S6.

METHODS

A total of 151 whole blood samples, 10 chorionic villus samples, and 17 amniotic fluid samples were collected, including 106 SEA heterozygotes, 43 normal individuals, 10 Hb Bart's hydrops details, and 19 SEA deletions combined with other genotypes.Genotypes of these samples were determined by the Gap-PCR method. We perform a series of optimizations of the ddPCR system to ensure the performance of the entire ddPCR reaction, such as droplet stability, fluorescence clustering, sensitivity, and accuracy.

RESULTS

Our assay exhibited 99.4% (177/178) accuracy compared with the Gap-PCR method, and the minimum detection limit of DNA was 0.1 ng/μL.Both targets have reliable linearity, R2 = 0.9999 for the α-thalassemia SEA deletion allele and R2 = 1 for the wild-type allele. The coefficient of variation for α-thalassemia SEA deletion allele detection at 2 and 10 ng/μL concentrations was 5.42% and 1.91%, respectively. In contrast, the coefficient of variation for wild-type allele detection was 4.06% and 1.83%, demonstrating its high quantitative accuracy. In addition, the DropXpert S6 PCR system showed some advantages over other ddPCR instruments, such as reducing testing costs, simplifying and automating the workflow.

CONCLUSIONS

The DropXpert S6 PCR system provided a highly accurate diagnosis for α-thalassemia SEA deletion and can be used to detect α-thalassemia as an alternative method.

Exploring Appropriate Reference Intervals and Clinical Decision Limits for Glucose-6-Phosphate Dehydrogenase Activity in Individuals From Guangzhou, China

Background

Quantitative detection of glucose-6-phosphate dehydrogenase (G6PD) is commonly done to screen for G6PD deficiency. However, current reference intervals (RIs) of G6PD are unsuitable for evaluating G6PD-activity levels with local populations or associating G6PD variants with hemolysis risk to aid clinical decision-making. We explored appropriate RIs and clinical decision limits (CDLs) for G6PD activity in individuals from Guangzhou, China.

Methods

We enrolled 5,852 unrelated individuals between 2020 and 2022 and screened their samples in quantitative assays for G6PD activity. We conducted further investigations, including G6PD genotyping, thalassemia genotyping, follow-up analysis, and statistical analysis, for different groups.

Results

In Guangzhou, the RIs for the G6PD activities were 11.20-20.04 U/g Hb in male and 12.29-23.16 U/g Hb in female. The adjusted male median and normal male median (NMM) values were 15.47 U/g Hb and 15.51 U/g Hb, respectively. A threshold of 45% of the NMM could be used as a CDL to estimate the probability of G6PD variants. Our results revealed high hemolysis-risk CDLs (male: <10% of the NMM, female: <30% of the NMM), medium hemolysis-risk CDLs (male: 10%-45% of the NMM, female: 30%-79% of the NMM), and low hemolysis-risk CDLs (male: ≥ 45% of the NMM, female: ≥ 79% of the NMM).

Conclusions

Collectively, our findings contribute to a more accurate evaluation of G6PD-activity levels within the local population and provide valuable insights for clinical decision-making. Specifically, identifying threshold values for G6PD variants and hemolysis risk enables improved prediction and management of G6PD deficiency, ultimately enhancing patient care and treatment outcomes.

Transfusion burden and willingness to pay for temporary alleviation of anemia status in transfusion-dependent beta-thalassemia patients in China

BACKGROUND

Transfusion-dependent β-thalassemia (TDT) is one of the global public health concerns highlighted by the World Health Organization. Patients with TDT require regular blood transfusion to survive. However, the availability of blood resources is extremely limited. The purpose of this study was to investigate transfusion burden and willingness to pay (WTP) for temporary remission of anemia status among patients with TDT and to explore the associated factors.

METHODS

Adult patients with TDT were recruited through cluster sampling across several high-incidence provinces in China. Consenting patients completed online questionnaires on demographic information, transfusion burden and WTP with real-time WeChat communication assistance from researchers. The guiding techniques of double-bounded dichotomous choices and open-ended questions in the contingent valuation method (CVM) were used to obtain participants' WTP for 1 unit of leukocyte-depleted red blood cells. WTP calculations were performed using maximum likelihood estimation, with further insights gained through subgroup analysis based on gender, family monthly income level and convenience of blood transfusion.

RESULTS

The analysis included 149 TDT patients from five high-incidence provinces, with an average monthly income of $198.5. Patients received an average of 3.7 units per transfusion, 15.4 times annually, with an average WTP of $70.4 per unit (95% CI [62.0, 78.9]). Estimated WTP for temporary anemia alleviation per transfusion totaled $260.6, exceeding monthly income by 1.32 times. Higher WTP was observed among males, higher-income households, and those with at least junior education. Lower WTP was noted among patients with lower transfusion volumes and those needing to travel for transfusion or during hospitalization for blood transfusion.

CONCLUSION

High WTP indicated a strong desire for temporary anemia relief. Most TDT patients faced significant economic and transfusion burden. The evident gap in meeting clinical needed underscores the urgent demand for innovative treatments to reduce transfusion dependency, potentially transforming TDT care and improving socioeconomic well-being and clinical outcomes. These findings supported evidence-based decision-making for TDT pharmacoeconomics and efficient healthcare resource allocation in China.

Prediction the Occurrence of Thalassemia With Hematological Phenotype by Diagnosis of Abnormal HbA1c

BACKGROUND

The current investigation aims to analyze the occurrence of thalassemia in patients who participated in hemoglobin A1c (HbA1c) testing in clinical laboratory showing high hemoglobin F (HbF) level (≥ 1.5%) or abnormal Hb peak and predict the main influence factors by using different statistical models.

METHODS

The current investigation is a single-center retrospective cohort study. HbA1c concentration was detected by using TOSOH HLC-723G8 glycated hemoglobin analyzer. SNaPshot SNP (Single Nucleotide Polymorphism) typing and AccuCopy technology were employed to detect mutations in thalassemia-related pathogenic genes.

RESULTS

A total of 126 patients endured high HbF levels or abnormal Hb peak during HbA1c detection, and 66.7% of subjects (n = 84) showed thalassemia mutations. Three heterozygosity mutations, including c.52A>T (p.K18*), c.-78A>G, and c.126_129delCTTT(p.F42Lfs*19) present in HBB gene, were also identified. --SEA/αα mutation demonstrated the youngest ages (p < 0.001). 17 M (p < 0.001) and 41/42 M (p < 0.01) mutations with β-thalassemia showed higher HbF levels compared with patients without thalassemia mutations. Except for -α3.7, mutations in thalassemia showed lower levels of mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) compared with patients without thalassemia mutations. Patients with thalassemia mutations showed younger age (p < 0.001), lower Hb (p < 0.001), MCV and MCH levels (p < 0.001), higher red blood cell (RBC) count (p < 0.001), and platelet distribution width (PDW) level (p = 0.007) than patients without thalassemia mutations. Three statistical models indicate MCV is the most valuable independent factor for predicting thalassemia and ROC (receiver operating characteristic) curves analysis of AUC (Area Under the Curve) of 0.855 (95% CI [0.787-0.923], p < 0.001) with MCV.

CONCLUSION

High HbF level (≥ 1.5%) or abnormal Hb peak present in HbA1c testing indicated high incident rate of thalassemia. MCV is the most valuable independent predicting factor for subjects having thalassemia.

Technically feasible solutions to challenges in preimplantation genetic testing for thalassemia: experiences of multiple centers between 2019 and 2022

PURPOSE

In clinical practice, the success of preimplantation genetic testing for monogenic diseases (PGT-M) for thalassemia was hindered by the absence of probands, incomplete family members, or failure in detecting embryonic gene mutation sites. This study aimed to address these issues.

METHODS

This retrospective study included 342 couples undergoing PGT-M for α- or β-thalassemia at three reproductive medicine centers from 2019 to 2022. Various methods were used to construct parental haplotypes. A total of 1778 embryos were analyzed and selected for transfer based on chromosomal ploidy and PGT-M results. Follow-up involved amniocentesis results and clinical outcomes.

RESULTS

Haplotypes were established using DNA samples from probands or parents, as well as sibling blood samples, single sperm, and affected embryos, achieving an overall success rate was 99.4% (340/342). For α-thalassemia and β-thalassemia, the concordance between embryo single nucleotide polymorphism (SNP) haplotype analysis results and mutation loci detection results was 93.8% (1011/1078) and 98.2% (538/548), respectively. Multiple annealing and looping-based amplification cycles (MALBAC) showed a higher whole genome amplification success rate than multiple displacement amplification (MDA) (98.8% (1031/1044) vs. 96.2% (703/731), p < 0.001). Amniocentesis confirmed PGT-M outcomes in 100% of cases followed up (99/99).

CONCLUSION

This study summarizes feasible solutions to various challenging scenarios encountered in PGT-M for thalassemia, providing valuable insights to enhance success rate of PGT-M in clinical practice.

Hemoglobin Bart's hydrops fetalis: charting the past and envisioning the future

ABSTRACT

Hemoglobin Bart's hydrops fetalis syndrome (BHFS) represents the most severe form of α-thalassemia, arising from deletion of the duplicated α-globin genes from both alleles. The absence of α-globin leads to the formation of nonfunctional hemoglobin (Hb) Bart's (γ4) or HbH (β4) resulting in severe anemia, tissue hypoxia, and, in some cases, variable congenital or neurocognitive abnormalities. BHFS is the most common cause of hydrops fetalis in Southeast Asia; however, owing to global migration, the burden of this condition is increasing worldwide. With the availability of intensive perinatal care and intrauterine transfusions, an increasing number of patients survive with this condition. The current approach to long-term management of survivors involves regular blood transfusions and iron chelation, a task made challenging by the need for intensified transfusions to suppress the production of nonfunctional HbH-containing erythrocytes. Although our knowledge of outcomes of this condition is evolving, it seems, in comparison to individuals with transfusion-dependent β-thalassemia, those with BHFS may face an elevated risk of complications arising from chronic anemia and hypoxia, ongoing hemolysis, iron overload, and from their respective treatments. Although stem cell transplantation remains a viable option for a select few, it is not without potential side effects. Looking ahead, potential advancements in the form of genetic engineering and innovative therapeutic approaches, such as the reactivation of embryonic α-like globin gene expression, hold promise for furthering the treatment of this condition. Prevention remains a crucial aspect of care, particularly in areas with high prevalence or limited resources.

A high stable sample loading for analysis of adult alpha-thalassemia via the improved microarray isoelectric focusing of Hb species

The isoelectric focusing has realized various improvements, including the protocols and creation of mIEF (microcolumn isoelectric focusing) instruments with excellent sensitivity for screening of diabetes and beta thalassemia. However, the problem of manual sample loading and hydration for the mIEF limits the operational capacity for stably detecting and quantitating most abnormal hemoglobin (Hb). Herein, we provided a high stable sample loading protocol for analysis of alpha thalassemia and Hb variants. In contrast to the previous volume of 20 μl, a 100 µl blood sample solution in this protocol was optimized with mixture of 6.4-7.5 and 3-10 pH carrier ampholytes, pI markers and loaded for 30 mins IPG microcolumn hydration. The hydrated microcolumn was then automatically loaded onto the mIEF chip array to which CH3COOH and NH4OH act as anodic and cathodic solutions. Lastly, the IEF was run for 9 mins. Hb H, Barts, A1c, F, A2 and CS were simultaneously separated and focused with higher resolution and sensitivity in quantifying H and Barts as low as 0.6 and 0.5 % respectively. Accordingly, there was an enhanced stability and linearity with a rapid assay time of 45 secs per sample. Moreover, analysis showed a fitting linear relationship with conventional technology at R2 = 0.9803 for H and R2 = 0.9728 for Barts thereby indicating greater accuracy confirmed by the AUC. Hence, the developed protocol could simply be employed for high stable and throughput batch sample loading of hydration, and accurate separation and quantitation of Hb variants for alpha and beta thalassemia.

A Case of Pernicious Anemia with Concurrent Beta-Thalassemia Minor

Vitamin B12 is essential for various bodily functions, and its deficiency may cause hematological manifestations. We report a case of a previously healthy 65-year-old female who was admitted to our hospital with reduced sense of taste and painful tongue. The serum level of vitamin B12 was decreased. However, her complete blood count did not show any evidence of macrocytosis, instead, her mean corpuscular volume was low. Gene sequencing indicated an β-thalassemia minor and that probably masked the megaloblastic features of vitamin B12 deficiency.

Effects of thalassemia minor on umbilical artery blood flow and perinatal outcomes in pregnancy: A retrospective cohort study

OBJECTIVE

The aim of the present study was to compare the fetal umbilical artery blood flow parameters in the third trimester and perinatal outcomes between pregnant women with and without thalassemia minor in South China.

METHODS

This was a retrospective cohort study. Doppler ultrasound was used to detect fetal umbilical artery hemodynamics in pregnant women with or without thalassemia minor during the third trimester. The main parameters assessed were umbilical artery peak systolic flow velocity/end-diastolic flow velocity (S/D), resistance index (RI), pulsation index (PI), and relevant perinatal outcomes.

RESULTS

This study included 540 pregnant women, 180 with thalassemia minor and 360 being healthy controls. In the third trimester, the thalassemia minor group had higher umbilical artery S/D (P = 0.002), RI (P = 0.002), and PI (P = 0.012) than healthy pregnant women, as well as lower levels of hemoglobin (Hb) (P < 0.001) and higher ferritin levels (P < 0.001). Compared to the non-thalassemia group, neonatal body weight in the thalassemia minor group was significantly lower (P = 0.001). Additionally, the incidence of maternal anemia (odds ratio [OR] 3.92; 95% confidence interval [CI]: 2.57-5.99, P < 0.001), low birth weight (OR 15.35; 95% CI: 1.71-137.93, P = 0.015), fetal distress (OR 2.18; 95% CI: 1.12-4.26, P = 0.023), neonatal asphyxia (OR 12.81; 95% CI: 1.40-117.33, P = 0.024), oligohydramnios (OR 18.25; 95% CI: 2.21-150.36, P = 0.007) and Apgar score <7 at 1 min after birth (OR 7.97; 95% CI: 1.53-41.54, P = 0.014) was significantly higher in the thalassemia minor group.

CONCLUSION

Pregnant women with thalassemia minor have higher umbilical artery S/D, RI and PI during the third trimester and a higher risk of adverse perinatal outcomes.

Routine antenatal molecular testing for α-thalassemia at a tertiary referral hospital in China: ten years of experience

Objective

This study aimed to evaluate the efficacy of α-thalassemia gene testing as a part of an antenatal intervention program over a 10-year period.

Methods

All patients underwent α-thalassemia gene testing, which included the analysis of three types of deletions and mutations. Rare α-thalassemia gene testing was performed using Sanger sequencing, multiplex ligation-dependent probe amplification, and sequencing techniques. Prenatal diagnosis was performed in high-risk couples using chorionic villus sampling or amniocentesis.

Results

From 2010 to 2019, among the 91,852 patients examined, α-thalassemia mutations were identified in 41.78% of patients. The most frequent α0 gene mutation was--SEA, followed by--THAI. Two rare α0-thalassemia gene mutations at --32.8 and --230, were also observed. A total of 2,235 high-risk couples were identified, of which 562 were affected, including three with the--SEA/--THAI genotype and one with the--SEA/--230 genotype. Additionally, prenatal diagnosis revealed four cases of fetal anemia and/or mild edema, along with two cases of severe fetal edema. Chromosome and gene chip results were normal. Thalassemia gene testing showed an αCSα/αCSα genotype in four patients with anemia and/or mild edema, while two patients with severe fetal edema had one--SEA/αCSα genotype and one--SEA/--GX genotype. Using the cut-off points of 74.6 fL and 24.4 pg as criteria for identifying α0-thalassemia carriers and HbH disease, the detection rate of missed diagnoses in high-risk couples is consistent with national guidelines for standards, potentially saving 10,217,700 ¥.

Conclusion

Routine molecular testing for α-thalassemia in high-risk prenatal populations effectively prevented severe α-thalassemia births. Despite the high cost, the cutoff points proposed by this study suggest that implementing screening using a new parameter has the potential to reduce current expenses.

The temporal trends of prevalence and years lived with disability of anaemia in China, Japan, and South Korea, from 1990 to 2021: Results from the Global Burden of Disease Study 2021

Background

Studies have shown that the disease burden of anaemia varies globally, yet they have not yet determined its exact extent in East Asian countries specifically. We thus aimed to investigate the prevalence and years lived with disability (YLDs) due to anaemia from 1990 to 2021 in China, Japan, and South Korea.

Methods

We extracted the prevalence and YLDs with their age-standardised rates (ASRs) in China, Japan, and South Korea from the Global Burden of Disease Study 2021, stratified by sex, age, and causes. We then examined the temporal trend of anaemia burden from 1990 to 2021 using joinpoint analysis and the association of anaemia burden with the Human Development Index and Universal Health Index through Spearman's correlation analysis.

Results

In 2021, anaemia affected 136 million people in China (95% uncertainty interval (UI) = 131, 141), with ASRs of prevalence of 8.9% (95% UI = 8.6, 9.3), and accounted for 3.0 million YLDs (95% UI = 2.0, 4.4). It affected 13.6 million people in Japan (95% UI = 11.8, 16.0), with ASRs of prevalence of 7.4% (95% UI = 6.1, 9.0), and caused 181 thousand YLDs (95% UI = 108, 282). It also affected 2.7 million individuals in South Korea (95% UI = 2.4, 3.0), with ASRs of prevalence of 5.2% (95% UI = 4.6, 5.7), and led to 34 thousand YLDs (95% UI = 22, 55). We observed a significant gender discrepancy in the anaemia burden in these three countries, with the prevalence and YLD rates in women being almost twice as high as those in men. Moreover, the peak age of the anaemia burden shifted toward higher age groups in all three countries, particularly in Japan. Chronic kidney disease was responsible for a growing share of anaemia cases and YLDs, especially in adults aged more than 60 years in Japan and South Korea. Haemoglobinopathies were another noticeable cause of anaemia in China, though dietary iron deficiency remained the leading cause. Both socioeconomic development and essential health service coverage showed negative associations with the anaemia burden in the three countries in the past three decades, though with differential patterns.

Conclusions

Anaemia remains a major public health issue in China, Japan, and South Korea; targeted surveillance and interventions are recommended for high-risk populations and cause-specific anaemia.

A novel discriminant algorithm for differential diagnosis of mild to moderate thalassemia and iron deficiency anemia

BACKGROUND

Mild to moderate thalassemia trait (TT) and iron deficiency anemia (IDA) are the most common conditions of microcytic hypochromic anemia (MHA) and they exhibit highly similar clinical and laboratory features. It is sometimes difficult to make a differential diagnosis between TT and IDA in clinical practice. Therefore, a simple, effective, and reliable index is needed to discriminate between TT and IDA.

METHODS

Data of 598 patients (320 for TT and 278 for IDA) were enrolled and randomly assigned to training set (278 of 598, 70%) and validation set (320 of 598, 30%). Stepwise discriminant analysis was used to define the best diagnostic formula for the discrimination between TT and IDA in training set. The accuracy and diagnostic performance of formula was tested and verified by receiver operating characteristic (ROC) analysis in validation set and its diagnostic performance was compared with other published indices.

RESULTS

A novel formula, Thalassemia and IDA Discrimination Index (TIDI) = -13.932 + 0.434 × RBC + 0.033 × Hb + 0.025 ×MCHC + 53.593 × RET%, was developed to discriminate TT from IDA. TIDI showed a high discrimination performance in ROC analysis, with the Area Under the Curve (AUC) = 0.936, Youden' s index = 78.7%, sensitivity = 89.5%, specificity = 89.2%, respectively. Furthermore, the formula index also obtained a good classification performance in distinguishing 5 common genotypes of TT from IDA (AUC from 0.854-0.987).

CONCLUSION

The new, simple algorithm can be used as an effective and robust tool for the differential diagnosis of mild to moderate TT and IDA in Guangxi region, China.

Prevalence of thalassemia-carrier couples and fertility risk assessment

Thalassemia is a highly prevalent hematologic disease in Guizhou, China. This study aimed to determine the epidemiological characteristics of thalassemia in couples at childbearing age and assess the neonatal risk of thalassemia in this subpopulation. A cohort of 4481 couples at childbearing age were recruited for thalassemia carrier screening by both traditional hematological tests and next-generation sequencing. Of them, 1314 (14.66%) thalassemia carriers were identified, including 857 (9.76%) α-thalassemia, 391 (4.36%) β-thalassemia, and 48 (0.54%) composite α and β-thalassemia. A total of 12 α-globin gene alterations and 16 β-globin mutations were detected, including four novel thalassemia mutations. SEA was the most common α-thalassemia genotype (26.86%), CD41-42 the most common β-thalassemia genotype (36.57%), and αα/- α3.7 + CD41-42 the most common composite α- and β-thalassemia genotype (18.75%). Ethnically, the Zhuang had the highest rate of thalassemia gene carriers among the ethnic groups. Geographically, Qiannan had the highest rate of thalassemia gene carriers. In addition, 38 of the 48 couples with composite α- and β-thalassemia were high-risk thalassemia carriers, and 4 carrying the -SEA/αα gene needed fertility guidance.

Effects of multidisciplinary team continuous care model on psychological behavior and quality of life in children with β-thalassemia major

OBJECTIVE

To explore the effects of a multidisciplinary team (MDT) continuous care model on psychological behavior and quality of life in children with β-thalassemia major (β-TM).

METHODS

A retrospective study was conducted on 90 children with β-TM who were hospitalized in the Department of Pediatrics, Affiliated Hospital of Youjiang Medical University for Nationalities from October 2021 to May 2022. According to nursing methods, the children were divided into a routine group and an experimental group, with 45 cases in each group. The routine group was intervened with routine nursing approaches, and the experimental group was intervened with the MDT continuous nursing mode on the basis of the control group. The psychological behavior [Positive and Negative Affect Scale for Children (PANAS-C)], quality of life (QoL) [Pediatric Quality of Life Inventory TM (PedsQLTM)] and satisfaction were compared between the two groups before and 6 months after intervention. The hemoglobin level and ferritin level of children after 3 months and 6 months of intervention were measured. The occurrence of complications and nursing satisfaction were recorded. The prognostic factors were further analyzed.

RESULTS

After the intervention, the positive emotion score, QoL score, hemoglobin level, satisfaction score in the experimental group were all higher than those in the conventional group, and the negative emotion score and ferritin level in the experimental group were all lower than those in the conventional group (all P < 0.05). The results of Cox analysis showed that the use of iron-removing drugs and arrhythmia/heart rate failure were risk factors affecting the prognosis of children with β-TM, while the MDT continuous nursing mode was a protective factor (all P < 0.05).

CONCLUSION

The MDT continuous care model can effectively promote mental health in children with β-TM, improve their quality of life, medical satisfaction, ameliorate the degree of anemia in children, reduce the incidence of complications and improve the prognosis; thus, it is worthy of wide clinical application.

Appropriate whole genome amplification and pathogenic loci detection can improve the accuracy of preimplantation genetic diagnosis for deletional α-thalassemia

Objective

To improve the accuracy of preimplantation genetic testing (PGT) in deletional α-thalassemia patients.

Design

Article.

Patients

fifty-two deletional α-thalassemia couples.

Interventions

Whole genome amplification (WGA), Next-generation sequencing (NGS) and PCR mutation loci detection.

Main outcome measures

WGA, Single nucleotide polymorphism (SNP) and PCR mutation loci detection results; Analysis of embryo chromosome copy number variation (CNV).

Results

Multiple Displacement Amplification (MDA) and Multiple Annealing and Looping-Based Amplification Cycles (MALBAC) methods for PGT for deletional α-thalassemia. Blastocyst biopsy samples (n = 253) were obtained from 52 deletional α-thalassemia couples. The results of the comparison of experimental data between groups MALBAC and MDA are as follows: (i) The average allele drop-out (ADO) rate, MALBAC vs. MDA = 2.27% ± 3.57% vs. 0.97% ± 1.4%, P=0.451); (ii) WGA success rate, MALBAC vs. MDA = 98.61% vs. 98.89%, P=0.851; (iii) SNP haplotype success rate, MALBAC vs. MDA = 94.44% vs. 96.68%, P=0.409; (iv) The result of SNP haplotype analysis is consistent with that of Gap-PCR/Sanger sequencing results, MALBAC vs. MDA = 36(36/72, 50%) vs. 151(151/181, 83.43%), P=0; (v) Valid SNP loci, MALBAC vs. MDA = 30 ± 9 vs. 34 ± 10, P=0.02; (vi) The mean CV values, MALBAC vs. MDA = 0.12 ± 0.263 vs. 0.09 ± 0.40, P=0.916; (vii) The average number of raw reads, MALBAC vs. MDA =3244259 ± 999124 vs. 3713146 ± 1028721, P=0; (viii) The coverage of genome (%), MALBAC vs. MDA = 5.02 ± 1.09 vs. 5.55 ± 1.49, P=0.008.

Conclusions

Our findings indicate that MDA is superior to MALBAC for PGT of deletional α-thalassemia. Furthermore, SNP haplotype analysis combined with PCR loci detection can improve the accuracy and detection rate of deletional α-thalassemia.

A cross-sectional study: caregiver burden and related determinants of adult patients with β-thalassemia major in mainland China

BACKGROUND

The informal caregivers of adult patients with β-thalassemia major (β-TM) bear not only physical but also emotional and economic pressures of providing care. This study is the first to evaluate the caregiver burden by Zarit Burden Interview (ZBI) of adult patients with β-TM in mainland China and to identify predictors of caregiver burden.

METHODS

In this cross-sectional study, we conducted an online survey with snowball sampling covering seven provinces between September 1, 2021, and January 31, 2022, of patients aged ≥ 18 years with β-TM and their informal caregivers. Caregiver burden was assessed using the ZBI. Data on patient demographics, disease and therapy characteristics, and informal caregivers' demographic characteristics were collected and analysed using independent t-tests, analysis of variance, Spearman's correlation and multiple linear regression.

RESULTS

Of 75 included patients, more than half (50.7%) were male. The mean patient age was 24.69 ± 5.59 years. The mean age of the informal caregivers was 50.60 ± 9.16 years, with women (74.7%) being predominant. The ZBI score was 38.00 ± 17.02. Multiple linear regression analysis showed that patients with interrupted blood transfusion therapy and informal caregivers required to care of others were positively associated with caregiver burden (p < 0.05). Age of informal caregivers were borderline significant positively associated with caregiver burden (p < 0.1). Married informal caregivers were negatively associated with caregiver burden (p < 0.05).

CONCLUSIONS

The informal caregivers of adult patients with β-TM in mainland China experienced a moderate-to-severe level of caregiving burden. The caregiver burden was higher in patients with a history of interrupted blood transfusion therapy or in informal caregivers who were older or needed to care for others. Additionally, married informal caregivers experienced lower burdens compared to non-married informal caregivers. These findings provide a reference to identify informal caregivers with higher burdens among patients with β-TM.

Carrier rate of thalassemia among 25,910 high school students in Shaoguan area, China

OBJECTIVES

As one of the most common hereditary diseases, thalassemia affects a large number of people in China. The aim of this study was to investigate the feasibility of a method based on next-generation sequencing (NGS) for screening of thalassemia carriers among high school students in the Shaoguan area.

MATERIALS AND METHODS

The NGS-based method was performed using 25,910 high school students recruited from 38 schools. The screening yield was systematically analyzed. Before screening, a lecture on how the disease is inherited, the symptoms of thalassemia, and how to prevent it was given to 28,780 students.

RESULTS

Implying successful delivery of information on the disease, 90.03% (25,910 of 28,780) of the students agreed to join this program for thalassemia screening. A thalassemia carrier rate of 15.99% (4144 of 25,910) was found. Also, 69 rare genotypes (28 of α-thalassemia and 41 of β-thalassemia) and 9 novel variants were identified.

CONCLUSIONS

This NGS-based method provided a feasible platform for high school population thalassemia screening. Combined with a clinical follow-up strategy, it could help eventually to prevent the births of affected children.

Molecular Characterization of α- and β-Thalassemia Among Children Less Than 18 Years Old in Guizhou, China

BACKGROUND

Thalassemia is an inherited hemolytic disease, the complications and sequelae of which have posed a huge impact on both patients and society. But limited studies have investigated the molecular characterization of α- and β-thalassemia in children from Guizhou, China.

METHODS

Between January 2019 and December 2022, a total of 3301 children, aged 6 months to 18 years, suspected of having thalassemia underwent molecular analysis.

RESULTS

Out of the total sample, 824 (25%) children were found to carry thalassemia mutations. The carrier rates of α-thalassemia, β-thalassemia, and α + β-thalassemia were determined as 8.1%, 15.6%, and 1.3%, respectively. Approximately 96.5% of the α-thalassemia gene mutations were --SEA (51%), ααCS (20.9%), -α3.7 (19.6%), and -α4.2 (5.0%). The most prevalent mutations of β-thalassemia were βCD17(A>T) (41.5%), βCD41-42(-TTCT) (37.7%), and βIVS-II-654(C>T) (11.3%). Additionally, we identified rare cases, including one case with ααHb Nunobiki/αα, two cases with triplicated α-thalassemia (one case with ααα/ααα and βCD41-42/βN and the other with ααα-3.7/αα and βE CD26/βN), and also one case with α Q-Thailandα/-α4.2 and βCD41-42/βN.

CONCLUSIONS

Our study findings provide important insights into the heterogeneity of thalassemia carrier rates and molecular profiles among children in the Guizhou region. The findings support the development of prevention strategies to reduce the incidence of severe thalassemia in the future.

Genotype analysis of 55,281 cases of thalassemia in northern Guangxi

OBJECTIVE

To understand the genotype and distribution of thalassemia in northern Guangxi.

METHODS

The study subjects were 55,281 individuals who came to the Affiliated Hospital of Guilin Medical University for genetic diagnosis of thalassemia from January 2012 to August 2023. All of their household registration was in the precincts of Guibei District and its affiliated counties. Red blood cell parameters and hemoglobin analysis were used for thalassemia screening. Gap-PCR, PCR-reverse dot blot hybridization (PCR-RDB), and multicolor melting curve analysis (MMCA) were used to identify common thalassemia genes. Multiplex ligation-dependent probe amplification (MLPA), Sanger sequencing, and third-generation single-molecule real-time (SMRT) sequencing were employed to identify rare thalassemia genes.

RESULTS

Among the 55,281 samples, 16,442 (29.74%) were diagnosed with thalassemia. The detection rates of α, β, and α combined β-thalassemia were 18.57%, 9.99% and 1.18%, respectively. Among ethnical groups, allele mutation frequency of thalassemia was the highest in Zhuang (44.97%), followed by Yao (40.11%), Dong (31.33%), Han (29.85%), Miao (24.31%), and Hui (20.6%). A total of 11,659 alleles (21.09%) of 8 types of α-thalassemia were identified in 55,281 samples, primarily --SEA (53.9%), followed by -α3.7 (21.3%), including rare alleles: --THAI (0.45%) and HKαα (0.38%). A total of 6367 (11.52%) and 14 types of β-thalassemia alleles were identified, mainly CD41-42 (50.12%), followed by CD17 (22.22%), including rare alleles: βCD37 (0.16%) and Gγ+ (Aγδβ)0/βN (0.05%). A total of 31 genotypes were detected in 10,264 cases of α-thalassemia, and the main types were --SEA/αα (53.23%), -α3.7/αα (19.15%), and -α4.2/αα (7.21%). A total of 34 genotypes were detected in 5525 cases of β-thalassemia, and the main types were βCD41-42/βN (50.53%), βCD17/βN (21.77%), and βIVS-II-654/βN (12.16%). A total of 78 gene types were detected in 653 cases of α- and β-thalassemia, and the main types were --SEA/αα, βCD41-42/βN (18.68%) and -α3.7/αα, βCD41-42/βN (13.02%). There were 580 cases (5.65%) of HbH disease (α0/α+), and 4 cases of Hemoglobin Bart's Hydrops Foetus syndrome (--SEA/--SEA). In addition, there were 92 cases (1.67%) of intermedia or severe types of β-thalassemia (β0/β0, β0/β+, β+/β+), including 23 cases of combined α-thalassemia. Among the samples screened negative for thalassemia, 3.7% of them were found to carry thalassemia genes, and 91.35% of the genotypes were αWSα/αα, -α3.7/αα, and -α4.2/αα. In addition, 40.26% of αWSα/αα, 22.89% of -α3.7/αα, and 18.51% of -α4.2/αα had no hematological phenotype.

CONCLUSION

The population in northern Guangxi exhibited rich ethnic diversity, with high allelic carrying rates among the Zhuang, Yao and Dong ethnic groups. Thalassemia gene mutations are diverse, encompassing a variety of gene types, with α thalassemia predominating, notably the --SEA/αα gene type. The prevalence of intermedia or severe types of thalassemia is not low, but there are still some carriers of thalassemia in people who are initially tested negative.

Carrier frequency estimation of pathogenic variants of autosomal recessive and X-linked recessive mendelian disorders using exome sequencing data in 1,642 Thais

BACKGROUND

People with autosomal recessive disorders often were born without awareness of the carrier status of their parents. The American College of Medical Genetics and Genomics (ACMG) recommends screening 113 genes known to cause autosomal recessive and X-linked conditions in couples seeking to learn about their risk of having children with these disorders to have an appropriate reproductive plan.

METHODS

We analyzed the exome sequencing data of 1,642 unrelated Thai individuals to identify the pathogenic variant (PV) frequencies in genes recommended by ACMG.

RESULTS

In the 113 ACMG-recommended genes, 165 PV and likely PVs in 60 genes of 559 exomes (34%, 559/1642) were identified. The carrier rate was increased to 39% when glucose-6-phosphate dehydrogenase (G6PD) was added. The carrier rate was still as high as 14.7% when thalassemia and hemoglobinopathies were excluded. In addition to thalassemia, hemoglobinopathies, and G6PD deficiency, carrier frequencies of > 1% were found for Gaucher disease, primary hyperoxaluria, Pendred syndrome, and Wilson disease. Nearly 2% of the couples were at risk of having offsprings with the tested autosomal recessive conditions.

CONCLUSIONS

Based on the study samples, the expanded carrier screening, which specifically targeted common autosomal recessive conditions in Thai individuals, will benefit clinical outcomes, regarding preconception/prenatal genetic carrier screening.

Mutation spectrum of thalassemia among pre-pregnant adults in the Jiangsu Province by capillary electrophoresis-based multiplex PCR assay

BACKGROUND

Thalassemia is a common genetic disorder in southwestern China, and an increasing number of cases from eastern China have been recently reported. Here, we developed a rapid, convenient, and accurate assay to evaluate the mutation spectrum of thalassemia in eastern China.

METHODS

A carrier screening assay for 61 hotspot variants among HBA1/HBA2 and HBB (OMIM: 141800, 141850, and 141900) genes was developed by SNaPshot/high-throughput ligation-dependent probe amplification (HLPA) technology. We used this assay to detect the mutation spectrum of thalassemia in individuals from eastern China and compared with the data collected from literatures focused on southern and northern China for variant distribution.

RESULTS

Among 4276 tested individuals, 2.62% (112/4276) were α-thalassemia carriers, with 90 carrying one deletion or mutation and 22 carrying two deletions. 0.40% (17/4276) were β-thalassemia carriers, and the most common variant of β-thalassemia was c.126_129delCTTT (29.41%) followed by c.316-197C>T (23.53%). The genotype distribution in our study was similar to those from southern China populations.

CONCLUSION

The Chinese population from different regions presented comparable mutation spectrum of thalassemia, and the SNaPshot/HLPA technique may serve as a capable assay for a routine genetic test in clinical practice with its accurate, rapid, and inexpensive advantage.

First Report of Filipino β0-Thalassemia/β-Thalassemia in a Chinese Family

A pregnant woman living in Fujian Province, southeastern China, presented due to a risk of having a baby with β-thalassemia major, during her second pregnancy, since she and her husband were suspected as β-thalassemia carriers and their affected daughter was a transfusion-dependent patient. Using the common α-thalassemia and β-thalassemia genotypes test, the pregnant woman was diagnosed as a β-thalassemia carrier with βIVS-2 - 654 (C→T)/βN genotype and her daughter had a homozygosity for IVS - 2 - 654 (C→T) mutation, however, no abnormalities were detected in her husband. SMRT identified a Filipino β0-deletion in her husband, and MLPA also revealed an unknown deletion in the HBB gene. Electrophoresis showed approximately 350 bp of the PCR product, and the β-Filipino genotype presented novel fracture fragments ranging from 5,112,884 to 5,231,358 bp, and lacked a 118,475 bp fragment relative to the wild-type sequence. The daughter was therefore diagnosed with the βIVS-2 - 654 (C→T)/βFilipino genotype. Prenatal diagnosis with umbilical cord blood at 27th week of gestation showed heteroztgosity for IVS - 2 - 654 (C→T) mutation in the fetus and continued pregnancy was recommended. In conclusion, we identified the Filipino β0-deletion in a Chinese family, from Fujian area, for the first time, during prenatal screening.

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

OBJECTIVES

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

SUBJECTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Prevalence and genetic analysis of triplicated α-globin gene in Ganzhou region using high-throughput sequencing

α-globin gene triplication carriers were not anemic in general, while some studies found that α-globin gene triplication coinherited with heterozygous β-thalassemia may cause adverse clinical symptoms, which yet lacks sufficient evidence in large populations. In this study, we investigated the prevalence and distribution of α-globin gene triplication as well as the phenotypic characteristics of α-globin gene triplication coinherited with heterozygous β-thalassemia in Ganzhou city, southern China. During 2021-2022, a total of 73,967 random individuals who received routine health examinations before marriage were genotyped for globin gene mutations by high-throughput sequencing. Among them, 1,443 were α-globin gene triplication carriers, with a carrier rate of 1.95%. The most prevalent mutation was αααanti3.7/αα (43.10%), followed by αααanti4.2/αα (38.12%). 42 individuals had coinherited α-globin gene triplication and heterozygous β-thalassemia. However, they did not differ from the individuals with heterozygous β-thalassemia and normal α-globin (αα/αα) in terms of mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) levels. In addition, heterogenous clinical phenotypes were found in two individuals with the same genotype. Our study established a database of Ganzhou α-globin gene triplication and provided practical advice for the clinical diagnosis of α-globin gene triplication.

The clinical value of hsa-miR-190b-5p in peripheral blood of pediatric β-thalassemia and its regulation on BCL11A expression

BACKGROUND

The B cell CLL/lymphoma 11A (BCL11A) is a key regulator of hemoglobin switching in β-thalassemia (β-thal). Previous study has suggested that dysregulated microRNAs are involved in the regulation of BCL11A expression. The aim of this study was to investigate the clinical value of hsa-miR-190b-5p in β-thal, and to confirm the regulatory effect of hsa-miR-190b-5p on BCL11A expression.

METHODS

The peripheral blood of 25 pediatric β-thal patients and 25 healthy controls were selected, and qRT-PCR was used to analyze the levels of hsa-miR-190b-5p and BCL11A mRNA. The relationship between hsa-miR-190b-5p expression and hematological parameters was assessed by Pearson's correlation test. The diagnostic power of hsa-miR-190b-5p was evaluated by ROC curves analysis. The direct integration between hsa-miR-190b-5p and BCL11A 3'-UTR was confirmed by luciferase reporter assay.

RESULTS

Hsa-miR-190b-5p expression in pediatric β-thal was upregulated, and negatively correlated with the MCH and HbA levels, but positively correlated with the HbF level. Hsa-miR-190b-5p showed a good diagnostic capability for pediatric β-thal equivalent to that of HbA2 (AUC: 0.760 vs. 0.758). Moreover, the levels of BCL11A mRNA in pediatric β-thal were decreased, and hsa-miR-190b-5p had a negative correlation with BCL11A mRNA expression (r = -0.403). BCL11A was a target gene of hsa-miR-190b-5p. The mRNA and protein levels of BCL11A were diminished by introduction of hsa-miR-190b-5p, whereas its expression was upregulated by knockdown of hsa-miR-190b-5p.

CONCLUSIONS

Hsa-miR-190b-5p expression was upregulated in pediatric β-thal and might be an effective diagnostic biomarker. BCL11A was negatively regulated by hsa-miR-190b-5p, which might provide new target for the treatment of pediatric β-thal.

Carrier burden of over 300 diseases in Han Chinese identified by expanded carrier testing of 300 couples using assisted reproductive technology

BACKGROUND

Expanded carrier screening (ECS) has become a common practice for identifying carriers of monogenic diseases. However, existing large gene panels are not well-tailored to Chinese populations. In this study, ECS testing for pathogenic variants of both single-nucleotide variants (SNVs) and copy number variants (CNVs) in 330 genes implicated in 342 autosomal recessive (AR) or X-linked diseases was carried out. We assessed the differences in allele frequencies specific to the Chinese population who have used assisted reproductive technology (ART) and the important genes to screen for in this population.

METHODOLOGY

A total of 300 heterosexual couples were screened by our ECS panel using next-generation sequencing. A customed bioinformatic algorithm was used to analyze SNVs and CNVs. Guidelines from the American College of Medical Genetics and Genomics and the Association for Molecular Pathology were adapted for variant interpretation. Pathogenic or likely pathogenic (P/LP) SNVs located in high homology regions/deletions and duplications of one or more exons in length were independently verified with other methods.

RESULTS

64.83% of the patients were identified to be carriers of at least one of 342 hereditary conditions. We identified 622 P/LP variants, 4.18% of which were flagged as CNVs. The rate of at-risk couples was 3%. A total of 149 AR diseases accounted for 64.05% of the cumulative carrier rate, and 48 diseases had a carrier rate above 1/200 in the test.

CONCLUSION

An expanded screening of inherited diseases by incorporating different variant types, especially CNVs, has the potential to reduce the occurrence of severe monogenic diseases in the offspring of patients using ART in China.

Economic burden of adult patients with β-thalassaemia major in mainland China

BACKGROUND

β-thalassaemia major poses a substantial economic burden, especially in adults. We aimed to estimate the economic burden of adult patients with β-thalassaemia major from a societal perspective using the real-world data. According to the clinical guideline, we also estimated the annual medical costs for patients with the same body weight and calculated the lifetime medical costs over 50 years in mainland China.

METHODS

This was a retrospective cross-sectional study. An online survey with snowball sampling covering seven provinces was conducted. We extracted patient demographics, caregiver demographics, disease and therapy information, caring burden, and costs for adult patients diagnosed with β-thalassaemia major and their primary caregivers. In the real world, we estimated the annual direct medical cost, direct nonmedical cost, and indirect cost. In addition, we calculated the annual direct medical cost and lifetime direct medical cost by weight with discounted and undiscounted rates according to the clinical guideline.

RESULTS

Direct medical costs was the main driver of total cost, with blood transfusion and iron chelation therapy as the most expensive components of direct medical cost. In addition, adult patients with β-thalassaemia major weighing 56 kg were associated with an increase of $2,764 in the annual direct medical cost using the real-world data. The undiscounted and discounted (5% discount rate) total lifetime treatment costs were $518,871 and $163,441, respectively.

CONCLUSIONS

Patients with β-thalassaemia major often encounter a substantial economic burden in mainland China. Efforts must be made to help policymakers develop effective strategies to reduce the burden and pevalence of thalassaemia.

Next-generation sequencing analysis of the molecular spectrum of thalassemia in Southern Jiangxi, China

BACKGROUND

Thalassemia is an extremely prevalent monogenic inherited blood disorder in southern China. It is important to comprehensively understand the molecular spectrum of thalassemia in an area with such a high prevalence of thalassemia before taking appropriate actions for the prevention and treatment of this disorder. Herein, we explored the clinical feasibility of using next-generation sequencing (NGS) for large-scale population screening to illustrate the prevalence and spectrum of thalassemia in Southern Jiangxi.

METHODS

Blood samples collected from 136,312 residents of reproductive age in Southern Jiangxi were characterized for thalassemia by NGS. A retrospective analysis was then conducted on blood samples determined to be positive for thalassemia.

RESULTS

In total, 19,827 (14.545%) subjects were diagnosed as thalassemia carriers, and the thalassemia prevalence rate significantly varied by geographical region (p < 0.001). A total of 40 α-thalassemia genotypes including 21 rare genotypes were identified, with -@-SEA/αα being the most prevalent genotype. 42 β-thalassemia genotypes including 27 rare genotypes were identified, with the most common mutation IVS II-654 C > T accounting for 35.257% of these β-thalassemia genotypes. Furthermore, 74 genotypes were identified among 608 individuals with combined α- and β-thalassemia. Notably, most individuals with rare thalassemia mutations had mildly abnormal hematologic parameters including microcytic hypochromia.

CONCLUSIONS

Our findings demonstrate the great heterogeneity and diverse spectrum of thalassemia in Southern Jiangxi, emphasizing the importance and necessity of persistent prevention and control of thalassemia in this region. Additionally, our findings further suggest that NGS can effectively identify rare mutations and reduce the misdiagnosis rate of thalassemia.

Utilization of multiple genetic methods for prenatal diagnosis of rare thalassemia variants

Background: Thalassemia is the most prevalent monogenic disorder caused by an imbalance between the α- and β-globin chains as a result of pathogenic variants in the α- or β-globin genes. Novel or complex structural changes in globin genes are major hurdles for genetic consulting and prenatal diagnosis. Methods: From 2020 to 2022, genetic analysis was performed on 1,316 families suspected of having children with thalassemia major, including 42 pregnant couples suspected of being thalassemia carriers with rare variants. Multiple techniques including multiplex ligation-dependent probe amplification (MLPA), Sanger sequencing, targeted next-generation sequencing, and single-molecule real-time (SMRT) sequencing were used to diagnose rare thalassemia. Results: The rate of prenatal diagnosis for rare thalassemia variants was 3.19% (42/1,316). The most prevalent alleles of α- and β-thalassemia are Chinese ^Gγ(^Aγδβ)⁰and -- ^THAI deletion. In addition, ten rare complex genotypes include one Chinese ^Gγ(^Aγδβ)⁰ deletion combined with HBG1-HBG2 fusion, two rare deletions at HBB gene (hg38, Chr11: 5224211-5232470, hg38, Chr11: 5224303-5227790), one complete 7,412 bp fusion gene for anti-Lepore Hong Kong, two complex rearrangements of the α-globin gene cluster, two novel duplications, and two rare large deletions in the α-globin gene cluster. Conclusion: Accurate gene diagnosis for probands with combined molecular biology techniques is the key to prenatal diagnosis of rare thalassemia.

Thalassaemia in China

Because of successful thalassaemia prevention programmes in resource-rich countries and it's huge population China now has the greatest number of new cases of thalassaemia globally as well as more people with thalassaemia than any other country. 30 million Chinese have thalassaemia-associated mutations and about 300,000 have thalassaemia major or intermedia requiring medical intervention. Over the past 2 decades there has been tremendous economic growth in China including per capita spending on health care. There is now nation-wide availability and partial or full insurance for prenatal genetic testing, RBC-transfusions, iron-chelating drugs and haematopoietic cell transplants. Prenatal screening and educational programmes have reduced the incidence of new cases. However, substantial challenges remain. For example, regional differences in access to medical care and unequal economic development require innovations to reduce the medical, financial and psychological burdens of Chinese with thalassaemia and their families. In this review we discuss success in preventing and treating thalassaemia in China highlighting remaining challenges. Our discussion has important implications for resource-poor geospaces challenged with preventing and treating thalassaemia.

Differences in medical costs between TCM users and TCM nonusers in inpatients with thalassemia

BACKGROUND

Thalassemia has brought serious health threats and economic burdens to patients worldwide. There is no sovereign remedy for thalassemia, both conventional and Traditional Medicine (TM) methods have certain effects on this disease. As typical of TM, Traditional Chinese Medicine (TCM) has been widely used in the treatment of thalassemia. Previous studies mainly focused on conventional treatments for thalassemia and patients' medical burden, but no research has examined the effects of TCM use on the economic burdens for thalassemia inpatients in mainland China. The main objective of this study is to compare the medical cost differences between TCM users and TCM nonusers, furtherly, we will discuss the role of TCM use in the treatment of thalassemia.

METHODS

We employed the 2010-2016 Medicare claims database provided by the China Health Insurance Research Association (CHIRA). Chi-square and Mann-Whitney tests were used to analyze the differences between TCM users and TCM nonusers. Multiple regression analysis was performed using the ordinary least squares method to compare the TCM users' inpatient medical cost with TCM nonusers', and to further examine the correlation between TCM cost, conventional medication cost and nonpharmacy cost for TCM users.

RESULTS

A total of 588 urban thalassemia inpatients were identified, including 222 TCM users and 366 TCM nonusers. The inpatient medical cost of TCM users was RMB10,048 (USD1,513), which was significantly higher than TCM nonusers (RMB1,816 (USD273)). Total inpatient cost for TCM users was 67.4% higher than those of TCM nonusers (P < 0.001). With confounding factors fixed, we found that the conventional medication cost and nonpharmacy cost were positively correlated with TCM cost.

CONCLUSION

Total hospitalization expenses for TCM users were higher than TCM nonusers. Both the conventional medication cost and nonpharmacy cost of TCM users were all higher than TCM nonusers. We infer TCM plays a complementary role, rather than an alternative, in the treatment of thalassemia due to the lack of cooperative treatment guidelines. It is recommended that a cooperative diagnosis and treatment guidelines should be generated to balance the use of TCM and conventional medicine for treating thalassemia, so as to reduce the economic burdens on patients.

TT@MHA: A Machine Learning-based Webpage Tool for Discriminating Thalassemia Trait from Microcytic Hypochromic Anemia Patients

BACKGROUND

Iron deficiency anemia (IDA) and thalassemia trait (TT) are the most common causes of microcytic hypochromic anemia (MHA) and are endemic in lower resource settings and rural areas with poor medical infrastructure. Accurate discrimination between IDA and TT is an essential issue for MHA patients. Although various discriminant formulas have been reported, distinguishing between IDA and TT is still a challenging problem due to the diversity of anemic populations.

METHODS

We retrospectively collected laboratory data from 798 MHA patients. High proportions of α-TT (43.33%) and TT concomitant with IDA (TT&IDA) patients (14.04%) were found among TT patients. Five machine learning (ML) approaches, including Liner SVC (L-SVC), support vector machine learning (SVM), Extreme gradient boosting (XGB), Logistic Regression (LR), and Random Forest (RF), were applied to develop a discriminant model. Performance was assessed and compared with six existing discriminant formulas.

RESULTS

The RF model was chosen as the discriminant algorithm, namely TT@MHA. TT@MHA was tested in an interlaboratory cohort with a sensitivity, specificity, accuracy, and AUC of 91.91%, 91.00%, 91.53%, and 0.942, respectively. A webpage tool of TT@MHA (https://dxonline.deepwise.com/prediction/index.html?baseUrl=%2Fapi%2F&id=26408&topicName=undefined&from=share&platformType=wisdom) was developed to facilitate the healthcare providers in rural areas.

CONCLUSION

The ML-based TT@MHA algorithm, with high sensitivity and specificity, could help discriminate TT patients from MHA patients, especially in populations with high proportions of α-TT patients and TT&IDA patients. Moreover, a user-friendly webpage tool for TT@MHA could facilitate healthcare providers in rural areas where advanced technologies are not accessible.

Brain iron content and cognitive function in patients with β-thalassemia

Patients with β-thalassemia (β-TM) may have brain iron overload from long-term blood transfusions, ineffective erythropoiesis, and increased intestinal iron absorption, leading to cognitive impairment. Brain magnetic resonance imaging (MRI) methods such as the transverse relaxation rate, susceptibility-weighted imaging, and quantitative susceptibility mapping can provide quantitative, in vivo measurements of brain iron. This review assessed these MRI methods for brain iron quantification and the measurements for cognitive function in patients with β-TM. We aimed to identify the neural correlates of cognitive impairment, which should help to evaluate therapies for improving cognition and quality of life in patients with β-TM.

Predicting thalassemia using deep neural network based on red blood cell indices

BACKGROUND AND OBJECTIVE

The traditional statistical screening method for thalassemia based on red blood cell (RBC) indices is being replaced by machine learning. Here, we developed deep neural networks (DNNs) that outperformed the traditional method for predicting thalassemia.

METHOD

Using a dataset of 8693 records comprising genetic tests and other 11 features we constructed 11 DNN models and 4 traditional statistical models and then compared their performances and analysed feature importance for interpreting DNN models.

RESULTS

The area under the receiver operating characteristic curve, accuracy, Youden's index, F1 score, sensitivity, specificity, positive predictive value and negative predictive value, were 0.960, 0.897, 0.794, 0.897, 0.883, 0.911, 0.914, and 0.882, respectively, for our best model, and compared with the traditional statistical model based on the mean corpuscular volume, these values were increased by 10.22%, 10.09%, 26.55%, 8.92%, 4.13%, 16.90%, 13.86% and 6.07%, respectively, and by 15.38%, 11.70%, 31.70%, 9.89%, 3.05%, 22.13%, 17.11% and 5.94%, respectively, for the mean cellular haemoglobin model. The DNN model performance will reduce without age, RBC distribution width (RDW), sex, or both WBC and PLT.

CONCLUSIONS

Our DNN model outperformed the current screening model. In 8 features, RDW and age were the most useful, followed by sex and the combination of WBC and PLT, the remaining nearly useless.

Genotypic and phenotypic characterization of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Guangzhou, China

BACKGROUND

G6PD deficiency is a common inherited disorder worldwide and has a higher incidence rate in southern China. Many variants of G6PD result from point mutations in the G6PD gene, leading to decreased enzyme activity. This study aimed to analyse the genotypic and phenotypic characteristics of G6PD deficiency in Guangzhou, China.

METHODS

In this study, a total of 20,208 unrelated participants were screened from 2020 to 2022. G6PD deficiency was further analysed by quantitative enzymatic assay and G6PD mutation analysis. The unidentified genotype of the participants was further ascertained by direct DNA sequencing.

RESULTS

A total of 12 G6PD mutations were identified. Canton (c.1376G>T) and Kaiping (c.1388G>A) were the most common variants, and different mutations led to varying levels of G6PD enzyme activity. Comparing the enzyme activities of the 6 missense mutations between the sexes, we found significant differences (P < 0.05) in the enzyme activities of both male hemizygotes and female heterozygotes. Two previously unreported mutations (c.1438A>T and c.946G>A) were identified.

CONCLUSIONS

This study provided detailed genotypes of G6PD deficiency in Guangzhou, which could be valuable for diagnosing and researching G6PD deficiency in this area.

Molecular spectrum of α- and β-thalassemia among individuals of reproductive age in the Zhuhai region of southern China

INTRODUCTION

Thalassemia is the most common monogenic disease in South and Southeast Asia. An accurate assessment of the relative frequency and composition of thalassemia mutations is important for the design of appropriate strategies to prevent the disease. In this study, we aimed to decode the molecular characterization of thalassemia mutations in Zhuhai region of southern China.

METHODS

A total of 8048 individuals who were potential thalassemia carriers were enrolled. Gap-polymerase chain reaction (Gap-PCR) and reverse dot-blot (RDB) hybridization methods were employed to detect common deletional and non-deletional thalassemia mutations. Multiplex ligation dependent probe amplification (MLPA) and Sanger sequencing were used to analyze and verify rare and complex mutations.

RESULTS

We diagnosed 3433 individuals as thalassemia carriers or patients. Of these, 2395 (69.76%) individuals with α-thalassemia harbored 13 α-globin gene mutations. The three most common α-thalassemia mutations were --^SEA (60.08%), -α^3.7 (20.62%) and -α^4.2 (9.25%). We diagnosed 903 (26.30%) individuals with β-thalassemia and identified 20 β-globin gene mutations, of which the three most frequent were CD41/42 (-TCTT) (38.10%), IVS-II-654 (C>T) (23.69%) and TATAbox-28 (A>G) (15.18%). In addition, we identified 15 rare thalassemia variants. We also summarized the association between the thalassemia genotype and hematological parameters, which demonstrated the broad phenotypic heterogeneity caused by globin gene mutations.

CONCLUSION

This is the first survey of thalassemia molecular epidemiology and hematological phenotype in Zhuhai region. It uncovered a high prevalence and complex molecular spectrum of thalassemia. These findings can be used as a basis for thalassemia diagnosis, counseling and prevention management.

The gene spectrum of thalassemia in Yangjiang of western Guangdong Province

Background: Thalassemia presents a higher incidence in southern China. The objective of this study is to analyze the genotype distribution of thalassemia in Yangjiang, a western city of Guangdong Province in China. Methods: The genotypes of suspected cases with thalassemia were tested by PCR and reverse dot blot (RDB). Unidentified rare thalassemia genotypes of the samples were further ascertained by PCR and direct DNA sequencing. Results: Among 22467 suspected cases with thalassemia, 7658 cases were found with thalassemia genotypes using our PCR-RDB kit. Among these 7658 cases, 5313 cases were found with α-thalassemia (α-thal) alone, --^SEA/αα was the most common genotype, accounting for 61.75% of α-thal genotypes, and the following mutations were found: α^3.7/αα, -α^4.2/αα, α^CSα/αα, α^WSα/αα, and α^QSα/αα. A total of 2032 cases were found with β-thalassemia (β-thal) alone. β^CD41-42/β^N, β^IVS-II-654/β^N, and β^-28/β^N accounted for 80.9% of all β-thal genotypes, and the following genotypes were found: β^CD17/β^N, β^CD71-72/β^N, and β^E/β^N. Compound heterozygotes of β-thal and β-thalassemia homozygotes were identified in 11 and five cases, respectively, in this study. α-thal combined with β-thal was identified in 313 cases, showing 57 genotype combinations of the coincidence of both Hb disorders; one extreme patient had a genotype of --^SEA/α^WSα and β^CD41-42/β^-28. In addition, four rare α-mutations (--^THAI, HKαα, Hb Q-Thailand, and CD31 AGG>AAG) and six rare β-mutations (CD39 CAG>TAG, IVS-Ⅱ-2 (-T), -90(C>T), Chinese ^Gγ⁺(Aγδβ)0, CD104 (-G), and CD19 A>G) were also found in this study population. Conclusion: This study provided detailed genotypes of thalassemia in Yangjiang of western Guangdong Province in China and reflected the complexity of genotypes in this high-prevalence region, and this would be valuable for diagnosis and counseling for thalassemia in this area.

Predictors of health state utility values using SF-6D for Chinese adult patients with β-thalassemia major

Background

Patients with β-thalassemia major (β-TM), predominantly adult patients, are associated with physical, mental, and social problems, that result in decreased quality of life (QoL). However, there is a paucity of data on QoL and health status utility (HSU) among adult patients with β-TM in mainland China. Our study aimed to evaluate the QoL by short form 36 questionnaire (SF-36) of adult patients with β-TM in mainland China and to estimate their HSU by SF-6D. In addition, we aimed to identify predictors of HSU.

Methods

In this cross-sectional descriptive study, a total of 75 adult patients with β-TM were included by the snowball sampling method that applied involving seven provinces with a relatively high prevalence of thalassemia across mainland China between September 1, 2021 and January 31, 2022. The collected information included social-demographic characteristics, health conditions, treatment, social support (social support rating scale), caregiver burden (Zarit burden interview), and QoL (SF-36). HSU scores were calculated for each adult patient from their SF-36 responses using the SF-6D algorithm with Hong Kong's tariff. The frequency of participants' responses to the SF-6D for each item of the options was described. Mean HSU scores between different subgroups were calculated. Ordinary least squares (OLS) regression modeling was performed to identify factors associated with HSU.

Results

A total of 75 adult patients with β-TM were included in this study. The mean SF-36 score was 50.2 ± 10.70, of which physical and mental scores were 47.57 ± 11.28 and 52.85 ± 14.21, respectively. In addition, the mean SF-6D utility score was estimated to be 0.598 ± 0.112, ranging from 0.391 to 0.962. Univariate analyses showed that interruption of iron chelation treatment significantly affected HSU values (P = 0.038); diagnosis with comorbidity very slightly affected HSU values (P = 0.0996). In the multivariate analysis, diagnosis with comorbidity (P = 0.042) was significantly negatively associated with HSU values; the minimum pre-transfusion hemoglobin concentration (P = 0.047) and social support (P = 0.068) were positively associated with HSU values.

Conclusion

This study presents poor QoL and HSU outcomes in Chinese adult patients with β-TM. The study also highlights the importance of social support and treatment compliance, which can increase hemoglobin content and reduce comorbidities, further to ensure the QoL of patients. These findings can be used for future clinical and economic studies.

A First Clinical and Molecular Study of Rare IVS-II-806 (G > C) (HBB:c.316-45G > C) Variant in the β-globin Gene: A Possibly Benign Variant

Introduction

β-thalassemia is a common genetic disease affecting a single gene, disease with a high incidence in South China. We hereby, aim to provide the clinical and hematological features of a rare β-globin gene variant in the Chinese population.

Methods

Ten subjects from three unrelated Chinese families were enrolled in this study. Hematological analysis and thalassemia gene testing were preformed to screen for common α and β-thalassemia variants. Gap-polymerase chain reaction (Gap-PCR) and DNA sequencing were utilized to examine the rare or novel thalassemia variants.

Results

Six cases were identified carrying the rare IVS-II-806 (G > C) (HBB:c.316-45G > C) variant in the β-globin gene. The proband in family 1 carry three rare β-globin gene mutations including CD39 (C > T), IVS-II-81 (C > T) and IVS-II-806 (G > C) combined with a --SEA/αα deletion, exhibiting the β-thalassemia trait. Further pedigree investigation indicated that the genotype of the proband in family 1 was --SEA/αα, βCD39 (C>T), IVS-II-81(C>T)/βIVS-II-806(G>C). Meanwhile, the twin girls in family 1 carrying the IVS-II-806 (G > C) mutation demonstrated a normal hematological phenotype. In family 2, the proband and his sister carry the IVS-II-806 (G > C) mutation, eliciting high levels of Hb A2 and slightly low levels of MCV and MCH. Moreover, the proband in family 3 carrying the same mutation exhibited a slightly low MCV level as well.

Conclusions

In this study, clinical and hematological analysis of the IVS-II-806 (G > C) mutation was first conducted within the Chinese population, with results indicating that it may be a benign variant.

The geo-spatial perspective of biological, social and environmental determinants of early pregnancy anaemia in rural Sri Lanka: Need for context-specific approaches on prevention

We provide a novel approach to understanding the multiple causations of maternal anaemia in a geospatial context, highlighting how genetics, environment and socioeconomic disparities at the micro-geographical level lead to the inequitable distribution of anaemia. All first-trimester pregnant women registered for the antenatal care programme in Anuradhapura District, Sri Lanka from July to September 2019 were invited to the Rajarata Pregnancy Cohort (RaPCo), which assessed the prevalence of anaemia in early pregnancy. The combination of the prevalence of anaemia and minor haemoglobinopathy-related anaemia (MHA) with the poverty headcount index of the 22 health divisions in the district was investigated using GeoDa spatial K-means clustering. Sociodemographic and economic data at the divisional level were compared between identified clusters. Combining the analysis with the geographical and environmental characteristics of the region, further hypotheses regarding anaemia in this community were formulated. The study included data from 3,137 pregnant women in early pregnancy. The anaemia and MHA prevalence varied from 13.6 to 21.7% and from 2.6% to 5%, respectively. We identified four distinct spatial clusters. The cluster with the highest anaemia prevalence also included high poverty and the highest prevalence of MHA. The clusters had significant differences with regard to ethnic distribution, access to water, sanitation and dietary patterns. Areas supplied by major irrigation projects had significantly low levels of anaemia, probably attributable to internal migration and improved livelihood. It was evident that genetic, socioeconomic and environmental risk factors were grouped at the divisional level, and that their complex interactions make controlling anaemia with blanket interventions unsuccessful. Analysis of the distribution of heterogeneous risk factors at the micro-geospatial level helped identify context-specific approaches to tackle anaemia in pregnancy.

The prevalence and genetic disorders spectrum of thalassemia among breast cancer patients in Jiangxi province, China

Background: Thalassemia is a common inherited hematological disease with genetic disorders characterized by imbalanced synthesis of the globin chains. Due to the improvement of treatment methods, patients with thalassemia can survive for a long time. Therefore, it is not uncommon for patients with thalassemia suffering from malignant tumors. However, there are quite few reports on thalassemia patients complicated with breast cancer. Herein, we try to investigate the prevalence and genetic disorders spectrum of thalassemia in patients with breast cancer. Methods: Blood routing tests and serum ferritin analysis were conducted in 1887 breast cancer patients treated in the department of radiation oncology during 1 April 2020 and 30 March 2022. The suspected thalassemia carriers with small mean corpuscular volume (MCV), mean corpuscular hemoglobin content (MCH) or mean corpuscular hemoglobin concentration (MCHC) but the concentration of serum ferritin within normal limits were further investigated by polymerase chain reaction (PCR) and flow through hybridization gene chip to detect common mutations of α-globin and β-globin genes using Thalassemia Geno Array Diagnostic Kit. The prevalence and genetic mutation spectrum of thalassemia among breast cancer patients were analyzed. Results: Four hundred and eighty-nine suspected thalassemia carriers were detected by complete blood cell counts and serum ferritin analysis among 1887 breast cancer patients. One hundred and seven cases (5.7%) were identified as carriers of thalassemia, of which 55 cases (51.4%) were α-thalassemia, 50 cases (46.7%) were β-thalassemia, and 2 cases (1.9%) were co-inheritance of α-thalassemia and β-thalassemia simultaneously. In α-thalassemia, the most prevalent genotype is -SEA/αα; as for β-thalassemia, βIVS-II-654/β is the most common genotype. The degree of anemia is more severe in β-thalassemia than in α-thalassemia. Conclusion: This is the first comprehensive molecular epidemiological investigation on thalassemia among breast cancer patients. Our data indicated that thalassemia was not uncommon in breast cancer patients. The physicians should have the knowledge to avoid misdiagnosis as iron deficiency anemia.

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

Background

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

Methods

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

Results

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

Conclusions

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

Investigation of the Distribution of Thalassemia in Children in Jiangxi Province, the People's Republic of China

Thalassemia is one of southern China's most common inherited disorders. Little is known about the genotypes of thalassemia in children in Jiangxi Province, the People's Republic of China (PRC). Two thousand, nine hundred and fifty-two children with suspected thalassemia were recruited from August 2016 to December 2020 at the Jiangxi Provincial Children's Hospital, Nanchang, PRC. Reverse dot-blot hybridization was used to detect α- and β-thalassemia (α- and β-thal) genotypes. A rare mutation was detected using gap-polymerase chain reaction (gap-PCR) and gene sequencing. The overall distribution of thalassemia (1534 cases) was 51.96%, and the detection rate of α-thal (616 cases), β-thal (888 cases) and concurrent α- and β-thalassemias (30 cases) was 20.86, 30.08, and 1.02%, respectively. A rare α-thal genotype, -α^27.6/- -^SEA (Southeast Asian), was identified. Seventy-eight cases of severe β-thal were detected, accounting for 8.78% of the cases, including 56 double heterozygous cases and 22 cases that were homozygous. Both α- and β-thalassemias are widely distributed in the children of Jiangxi Province. Thalassemia genetic testing is essential to establish a comprehensive thalassemia prevention program and improve public education.

Major Thalassemia, Screening or Treatment: An Economic Evaluation Study in Iran

BACKGROUND

Beta-thalassemia minor and thalassemia major are an autosomal recessive disease with hypochromic, microcytic anemia, and morbidities, Today, therapeutic advances have significantly improved the life expectancy of thalassemia major patients, but at the cost of financial toxicity. The present study aimed to investigate the possibility of increasing the funding for thalassemia screening programs and comparing the cost-effectiveness of screening for thalassemia in the treatment of the patients.

METHODS

In this study, screening for thalassemia minor was compared with the treatment of thalassemia major patients. A decision tree model was used for analysis. A hospital database, supplemented with a review of published literature, was used to derive input parameters for the model. A lifetime study horizon was used and future costs and consequences were discounted at 3%. The approach of purchases of services was used to evaluate the screening test costs for patients with thalassemia major. Also, a bottom-up method was applied to estimate other screening and treatment costs. All the costs were calculated over one year. The number of gained quality-adjusted life years (QALYs) was calculated using the EQ-5D questionnaire in the evaluated patients.

RESULTS

In this study, 26.97 births of patients with thalassemia major were prevented by screening techniques. On the other hand, total screening costs for patients with thalassemia major were estimated equal to US$ 879879, while the costs of preventing the birth of each thalassaemia major patient was US$ 32 624 by screening techniques. In comparison, the cost of managing a patient with thalassemia major is about US$ 136 532 per year. The life time QALYs for this is 11.8 QALYs. Results are presented using a societal perspective. Incremental cost per QALY gained with screening as compared with managing thalassaemia major was US$ 11 571.

CONCLUSION

Screening is a long-term value for money intervention that is highly cost effective and its long-term clinical and economic benefits outweigh those of managing thalassaemia major patients.

Prevalence and Genetic Analysis of Thalassemia and Hemoglobinopathy in Different Ethnic Groups and Regions in Hainan Island, Southeast China

Background: There are limited studies on the molecular profile of thalassemia in Hainan, the free trade island in China. Our aim was to reveal the prevalence and molecular mutation spectrum of thalassemia in different ethnic groups and regions of Hainan through a large sample study for the first time.

Methods: A total of 231,596 individuals from 19 cities and counties in Hainan were screened by hematological parameter analysis, and further genetic analysis was performed on individuals with MCV less than 82 fL.

Results: Totally, 31,780 (13.72%) subjects were diagnosed as thalassemia carriers. The overall prevalence of α-thalassemia, β-thalassemia, and α+β-thalassemia were 11.04%, 1.48%, and 1.20%, respectively. We further analyzed the molecular profiles of thalassemia in various ethnic groups and mainly compared the difference between Han and Li. The results showed that the frequency of thalassemia in the Li population (47.03%) was much higher than that in Han (9.37%). Except for β-thalassemia (1.31% of Li vs. 1.47% of Han), the frequencies of α-thalassemia (39.59% of Li vs. 7.35% of Han) and α+β-thalassemia (6.13% of Li vs. 0.56% of Han) in the Li were obviously higher than those in Han. The high-frequent genotypes of α-thalassemia in Han were αα/--SEA (25.55%), -α3.7/αα (22.17%), -α4.2/αα (21.59%), αWSα/αα (8.93%), and -α3.7/-α4.2 (4.17%) and those of Li were -α4.2/αα (17.24%), -α3.7/αα (17.16%), -α3.7/-α4.2 (15.09%), αWSα/αα (9.69%), and αWSα/-α3.7 (8.06%), respectively. The αα/--SEA was the highest genotype of α-thalassemia in Han but only accounted for 1.87% in Li. For β-thalassemia, the top three high-frequent genotypes in both Han and Li were βCD41/42(-TTCT)/βN, β-28(A&gt;G)/βN, and βIVS-Ⅱ-654(C&gt;T)/βN, but the frequency of βCD41/42(-TTCT)/βN in Li (90.96%) was much higher than that in Han (56.32%) and the data reported in other provinces of China. Additionally, the prevalence of thalassemia ranged from 8.16% to 34.35% in Hainan, Wuzhishan, Baoting, Qiongzhong, and Baisha have a higher prevalence than other areas.

Conclusion: Our study revealed the characteristics of ethnic and regional differences in the prevalence of thalassemia in the childbearing age population of Hainan for the first time, indicating that the prevalence of thalassemia among Li nationality is the highest in China. Those findings will be useful for genetic counseling and the prevention of thalassemia.

Spectrum of β-Thalassemia Mutations in Some Areas of Guangxi Zhuang Autonomous Region of Southern China: A Study on a Pediatric Population Aged 0-15 Years

β-Thalassemia (β-thal), one of the most common form of single-gene inheritable blood diseases in the world, is highly prevalent in southern China, especially in the Guangxi Zhuang Autonomous Region. To update the β-thal mutation spectrum in this region, we performed hematological and genetic analyses on 888 β-thal major (β-TM), β-thal intermedia (β-TI) and β-thal carrier patients, aged 0-15 years old, from different parts of Guangxi Province. We identified 55 genotypes and 18 β-thal mutations. The codons 41/42 (-TTCT) (HBB: c.126_129delCTTT) (43.97%), codon 17 (A>T) (HBB: c.52A>T) (25.43%), -28(A>G) (HBB: c.-78A>G) (8.18%), IVS-II-654 (C>T) (HBB: c.316-197C>T) (7.85%) and codon 26 (G>A) (HBB: c.79G>A) (5.02%) were the five most common, accounting for more than 90.0%. The results of our study are providing an up-to-date β-thal mutation spectrum in the 0-15-year-old pediatric population, which will help genetic counseling and prevention of β-TM in mainland China's most endemic region, Guangxi Zhuang Autonomous Region.

Establishment of pregnant-specific intervals for hemoglobin (Hb) A2, HbF and cut-off points for HbA2 for thalassemia in Chongqing, China

OBJECTIVES

To analyze pregnant-specific intervals for hemoglobin A2 (HbA2), hemoglobin fetal (HbF), and cut-off points of HbA2 for thalassemia in Chongqing, China.

METHODS

Between September 2015 and April 2019, the study recruited 10039 individuals of reproductive age. Of which, 4399 healthy normal individuals were selected to determine reference values for HbA2 and HbF. The remaining 5640 individuals suspected of thalassemia were included to explore the cut-off points of HbA2 for thalassemia.

RESULTS

The reference values of HbA2 in males was 2.3-3.2%, in females was 2.1-3.1%, and in pregnant women was 1.9-3.1%. While the reference values of HbF in males was 0.0-0.0%, in females was 0.0-0.9%, and in pregnant women was 0.0-4.3%. Approximately 2.3% cut-off points for pregnant women was determined to be optimal for α-thalassemia screening. In the entire group, 2.5% was best for all α-thalassemia screenings. The cut-off for β-thalassemia screening using HbA2 was 3.2% for the entire group.

CONCLUSION

The reference interval of HbA2 for pregnant females group was significantly lower than other groups. Therefore, we recommend cut-off points of HbA2 for α-thalassemia at 2.3% for pregnant women. While partitioning was not needed due to gender. Gender and pregnancy had little effect on the cut-off points of HbA2 for β-thalassemia carrier.