Thalassemia Screening Research Articles

Wooden-Tip Electrospray Mass Spectrometry Characterization of Human Hemoglobin in Whole Blood Sample for Thalassemia Screening: A Pilot Study

Traditional analytical methods for thalassemia screening are needed to process complicated and time-consuming sample pretreatment. In recent decades, ambient mass spectrometry (MS) approaches have been proven to be an effective analytical strategy for direct sample analysis. In this work, we applied ambient MS with wooden-tip electrospray ionization (WT-ESI) for the direct analysis of raw human blood samples that were pre-identified by gene detection. A total of 319 whole blood samples were investigated in this work, including 100 α-thalassemia carriers, 67 β-thalassemia carriers, and 152 control healthy samples. Only one microliter of raw blood sample was directly loaded onto the surface of the wooden tip, and then five microliters of organic solvent and a high voltage of +3.0 kV were applied onto the wooden tip to generate spray ionization. Multiply charged ions of human hemoglobin (Hb) were directly observed by WT-ESI-MS from raw blood samples. The signal ratios of Hb chains were used to characterize two main types of thalassemia (α and β types) and healthy control blood samples. Our results suggested that the ratios of charged ions to Hb chains being at +13 would be an indicator for β-thalassemia screening.

Screening of Thalassemia Carrier Traits in Students Using the One Tube Osmotic Fragility Method

Thalassemia is an inherited disorder resulting from a mutation or deletion of a gene that causes one of the globin chains to experience a decrease or cessation in the rate of synthesis. This leads to a decrease in the rate of haemoglobin synthesis. The highest prevalence of thalassemia in the world is found in tropical countries. The incidence of thalassemia carriers in Indonesia ranges from 6-10%. Thalassemia screening can be carried out by several examinations, including one tube osmotic fragility (OTOF) examination, red blood cell index, peripheral blood morphology and electrochemistry of haemoglobin. This study aimed to examine the screening of thalassemia carriers in undergraduate students using osmotic fragment examination of the OTOF method. This study used descriptive methods with 100 TLM D3 female students not yet known to have thalassemia. Univariate analyses were carried out. The results of the capillary blood samples indicated that 12% of the students were positive (indicating a suspected carrier of thalassemia) and 88% were negative according to the OTOF method using a hypotonic solution of 0.36% NaCl. From the positive OTOF results, the percentage of haemolysis was measured with varying results (17% - 65%). Those who had positive OTOF results in general were without significant symptoms. The findings accentuate that early detection of thalassemia is important.
 Keywords: thalassemia, OTOF, microcytic, hypochromic

New Progress in Laboratory Detection of Abnormal Hemoglobinopathies

Abnormal hemoglobinopathies are a group of hereditary diseases caused by Hb variants with new molecular structure changes due to globin defects and changes in the primary structure of globin. It is one of the most common birth defects and ranks third in global incidence [1]. Compared with thalassemia, most abnormal hemoglobinopathies are clinically asymptomatic and have a low incidence rate, which makes the awareness of the disease not widespread enough. Therefore, there is no mature and independent screening and diagnosis program at present, and abnormal hemoglobinopathies are often It is accompanied by abnormalities found in thalassemia screening, and then can be diagnosed by genetic sequencing.

T237 Comparison study between a lateral flow immunochromatographic assay and haemoglobin H staining for the screening of alpha thalassaemia

T237 Comparison study between a lateral flow immunochromatographic assay and haemoglobin H staining for the screening of alpha thalassaemia

Detection of rare thalassemia mutations using long-read single-molecule real-time sequencing.

Gap- polymerase chain reaction (PCR), reverse dot-blot assay (RDB), real-time PCR based multicolor melting curve analysis (MMCA assay), multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing are conventional methods to diagnose thalassemia but all of them have limitations. In this study, we applied single-molecule real-time (SMRT) sequencing following multiplex long-range PCR to uncover rare mutations in nine patients and their family members. The patients with different results between Gap-PCR and MMCA assay or with phenotype not matching genotype were included. Using SMRT sequencing, we first identified the carriers with αααanti3.7/HKαα, -α762bpα/αα (chr16:172,648-173,409), ααfusion/αQSα (in a trans configuration), two cases with novel gene rearrangements and another case with a novel 341bp insertion in α-globin gene cluster, respectively. One carrier with --SEA/αααanti4.2, and two carriers with the coexistence of globin variant and an α-globin gene duplication were also found. Most importantly, we could determine two defects in α-globin gene cluster being a cis or trans configuration in a single test. Our results showed that SMRT has great advantages in detection of α-globin gene triplications, rare deletions and determination of a cis or trans configuration. SMRT is a comprehensive and one-step method for thalassemia screening and diagnosis, especially for detection of rare thalassemia mutations.

Loop-mediated isothermal amplification (LAMP) colorimetric phenol red assay for rapid identification of α0-thalassemia: Application to population screening and prenatal diagnosis

BackgroundIdentification of α0-thalassemia (SEA and THAI deletions) is essential in preventing and controlling of severe thalassemia diseases. We have developed the LAMP colorimetric assays for the detection of these two thalassemia defects and validated them in population screening and prenatal diagnosis.MethodsThree LAMP colorimetric assays specific for α0-thalassemia (SEA deletion), α0-thalassemia (THAI deletion) and normal DNA sequence were developed. These assays were validated on 341 subjects who had initial thalassemia screening positive and various thalassemia genotypes. Prenatal diagnosis of α0-thalassemia (SEA deletion) was done on 33 fetuses at risk of having Hb Bart’s hydrops fetalis syndrome.ResultsThe LAMP colorimetric assays for α0-thalassemia (SEA and THAI deletions) could be clearly interpreted by naked eyes. The assay for α0-thalassemia (SEA deletion) showed a 100% (62/62 x 100) sensitivity and 98.2% (274/279 x 100) specificity whereas, that of the α0-thalassemia (THAI deletion) showed 100% (1/1 x 100) sensitivity and 99.7% (339/340 x 100) specificity. We obtained a 100% concordant prenatal diagnosis results using LAMP assays of α0-thalassemia (SEA deletion) in 33 fetuses as compared to the conventional PCR analysis.ConclusionsThe LAMP colorimetric assays developed are simple, rapid, and do not require sophisticated equipment. Inclusion of the LAMP tests in the existing screening protocol significantly reduce the screening cost and the molecular analysis workload, which should prove useful in the prevention and control program of hemoglobinopathies in the region.

Anemia in Pregnancy: A knowledge, Attitude and Practice Survey Amongst Obstetricians and Gynaecologists in India.

Anemia continues to affect one-third of the global population and is one of the most common reasons for large-scale morbidity and mortality especially among women. The importance of iron-rich diet has always been the backbone of preventing iron deficiency anemia (IDA) in vulnerable age groups followed by oral iron therapy and parenteral iron therapy as the next options in management of iron deficiency. Objective of this survey was to assess the knowledge, attitude and practices of obstetricians and gynaecologists relevant to anemia in pregnancy and identify the practice gaps in management of anemia in pregnancy. This was a knowledge, attitude and practice (KAP) survey involving obstetricians and gynaecologists (ObGyns) across India. A validated questionnaire of twenty questions was used to assess knowledge, attitude and practice about anemia and its management. Results were expressed as percentages. 1974 ObGyns participated in the survey. 88.7% ObGyns screen anemia in first trimester, 53.7% ObGyns perform CBC along with RBC indices. Majority of ObGyns estimate Hb thrice during antenatal period. 50% ObGyns do not consider thalassemia screening routinely and deworming regularly. 92.4% ObGyns believe that iron supplementation is required even if Hb > 11g/dL. Majority of them prefer low-dose iron therapy, 59.9% prefer to use 100mg oral iron daily. Almost half of ObGyns prefer to change iron salt when patients do not respond, instead of escalating to injectable iron. Interestingly 52% ObGyns evaluate serum ferritin before starting intravenous iron therapy. 43.5% perform Hb estimation as early as 2weeks after IV iron therapy. Majority (82.2%) of ObGyns prefer blood transfusion as a treatment of choice when Hb < 5g/dl at 34weeks gestation. Only 40.5% of participants are aware of the exact cut-off for diagnosing postpartum anemia. Majority of the ObGyns are aware of the iron prophylaxis in postpartum period till 3-6months. More than 90% ObGyns consider intravenous iron for severe anemia of postpartum period. The present KAP survey highlights the observation, perception and the practicing behaviour of obstetricians and gynaecologists on anemia in pregnancy and identifies practice gaps in anemia management.

Thalassemia Gene Detection Results and Application Value of Hematological Indexes Among Pregnant Women in Xindu District of Chengdu City

To analyze the genotype characteristics of α- and β-thalassemia and the diagnostic value of hematological indexes in pregnant women in Xindu District of Chengdu. The blood routine parameters(MCV) <80 fl and (or) (MCH) <27 pg and hemoglobin electrophoresis were used to screen the pregnant women, PCR-reverse dot blot hybridization(PCR-RDB) technique was used to detect the common α- and β-thalassemia gene types in the primary screening positive population. The husbands of the diagnosed pregnant women were recalled for gene testing, and the highly suspected patients were checked by gene sequencing. Among the 7 049 pregnant women, 1 740(24.68%) cases were positive for primary screening. 180 patients were diagnosed as thalassemia gene positive, among them, 94 cases (52.22%) of α-thalassemia were detected and six genotypes were found, in which --SEA /αα genotype was the highest (58 cases, 61.70%); 82 cases (45.56%) of β-thalassemia were detected and ten genotypes were found while CD41-42/N and CD17/N genotypes were the most common; there were 4 cases(2.22%) with α combined with β-thalassemia. Through clinical follow-up survey, there were 4 couples with the same type of thalassemia, one of them was induced labor after diagnosis of hemoglobin H disease. Receiver operating curve (ROC curve) was used to analyze the diagnostic value of hematological parameters in thalassemia positive pregnant women. The results showed that AUC(HBA2)<AUC(MCHC)<AUC(RDW-SD)<AUC(MCH)<AUC(MCV) (P<0.01). The most common genotypes of α- and β-thalassemia in pregnant women in Xindu District of Chengdu were --SEA /αα, CD41-42/N, CD17/N. The blood routine indicators (HBA2、RDW-SD、MCHC、MCH、MCV) have high diagnostic value for screening of thalassemia.

Clinical Performance Study of a New Fully Automated Red Blood Cell Permeability Fragility Analyzer.

In order to verify the applicability of the erythrocyte fragility test (EFT) carried out by the new fully automatic erythrocyte permeability fragility analyzer RA-800 for thalassemia screening, a total of 100 cases of suspected thalassemia patients who underwent pregnancy examinations at Luohu District People's Hospital are included. The results of a new automatic erythrocyte permeability fragility analyzer RA-800 are compared with the results of the detection system composing of the KOFA erythrocyte fragility test kit currently used in clinical laboratories. The diagnosis confirmed by genetic testing is used as the gold standard to evaluate the applicability of RA-800. The sensitivity, specificity, and accuracy of the new automatic erythrocyte permeability fragility analyzer RA-800 screening for thalassemia were 66.67%, 92.86%, and 85.00%. The KOFA direct colorimetries are 76.67%, 81.43%, and 80.00%. The kappa value for the screening of thalassemia was 0.558, which concludes that the consistency was moderate. The ROC curve indicates that both two methods had diagnostic significance for the diagnostic value of thalassemia. The new automatic erythrocyte permeability fragility analyzer RA-800 is suitable for thalassemia screening, and the performance indexes meet the clinical requirements.

Thalassemia screening: Low level of knowledge among unmarried youths in Kota Bharu, Kelantan, Malaysia.

Thalassaemia is a common genetic blood disorder. Knowledge, awareness, attitude towards, and intention to screen for thalassaemia among Malaysians is poor. Screening for thalassaemia in unmarried individuals plays a key role in preventing thalassaemia major births. A cross-sectional study was conducted on unmarried individuals aged 18 years and older in Kota Bharu, Kelantan, Malaysia. A questionnaire was used to collect the general data of the participants, their knowledge of thalassaemia, attitude towards thalassaemia, and intention to screen for thalassaemia. A total of 278 respondents were included in this study. The mean (SD) knowledge score was 8.8 (4.99) out of a possible score of 21, with higher scores indicating better knowledge. The factor associated with good knowledge of thalassaemia was being a professional. Most respondents agreed that unmarried individuals should be screened for thalassaemia before marriage. In conclusion, knowledge of thalassaemia among unmarried individuals who were not professionals was low.

The prevalence and outcomes of α- and β-thalassemia among pregnant women in Hubei Province, Central China: An observational study.

There is no information concerning the prevalence of thalassemia among pregnant women in Hubei Province currently. This study is aimed to explore the prevalence of α- and β-thalassemia genotypes among pregnant women in Hubei Province, and to explore the clinically applicable screening approach, as well as to investigate the pregnancy outcomes of α- and β-thalassemia carriers.Pregnant participants were recruited from 4 hospitals for the screening of α- and β-thalassemia mutations in Hubei Province. Polymerase Chain Reaction and flow cytometry methods were used to examine α- and β-thalassemia mutations. The hematological parameters and pregnancy outcomes of α- and β-thalassemia carriers were obtained from the hospital information system. The chi-square tests were used to evaluate the difference in hematological parameters between pregnant thalassemia carriers and the control group.Among 11,875 participants, 414 (3.49%) were confirmed with α-thalassemia carriers, 228 (1.92%) were confirmed with β-thalassemia carriers, and 3 (0.03%) were confirmed with both α- and β-thalassemia carriers. The frequency of –α3.7 accounted for 2.05% and it was the most frequent genotype of α-thalassemia; the proportion of IVS-II-654 was 0.85% and it was the most frequent genotype of β-thalassemia in Hubei Province. Furthermore, the proportion of patients with low mean corpuscular volume (MCV) or mean cell hemoglobin (MCH) values was accounted for 36.64% and 93.97% among α-thalassemia and β-thalassemia carriers, respectively. And participants with normal MCV and MCH values were accounted for 95.07% among non-thalassemia participants. High prevalence of pregnancy-induced diabetes (16.97%), preterm birth (9.96%), pregnancy-induced hypertension (8.12%), and low birth weight (5.90%) were observed among pregnant thalassemia carriers.MCV and MCH values were suggested to apply on the preliminary screening of pregnant β-thalassemia; however, it's unpractical on that of α-thalassemia. Furthermore, thalassemia carriers might have a high risk of negative pregnancy outcomes. These findings could be useful for the preliminary screening of thalassemia and perinatal care for the pregnant thalassemia carriers.

Prevalence and Genetic Analysis of β-Thalassemia in the Dali Bai Autonomous Prefecture of the Yunnan Province, China.

Background: β-Thalassemia is the most common monogenetic hemolytic hemoglobin-associated disease in the south of China; the distribution of genetic mutations associated with this condition varies according to geographic regions. This study investigated the prevalence and distribution of β-thalassemia-associated mutations across different ethnic groups in the Dali Bai Autonomous Prefecture of the Yunnan Province, China. Methods: This cross-sectional study included 4723 participants (15-45 years old) who volunteered for thalassaemia screening from the Dali Bai Autonomous Prefecture from May 2017 to October 2020. Cellulose acetate membrane electrophoresis was used to screen for β-thalassemia carriers. Genotypic analyses was performed using polymerase chain reaction-based reverse dot blotting and DNA sequencing. Results: The overall prevalence of β-thalassemia in the study population was 2.01%. The genotypic analyses showed the presence of four types of mutations in the β-globin gene: CD26 (GAG→AAG), CD56 (GGC→GAC), IVS-II-81 (C→T), and CD121 (GAA→CAA). In contrast to previous studies from other regions of Yunnan Province, our results showed that the prevalence of CD26 mutations was significantly higher than that of the other mutations. Conclusion: Our data suggests that the Dali Autonomous Prefecture is an area with a high prevalence of β-thalassemia. Moreover, CD26 was the only β-thalassemia mutation that we have detected. Moreover, the vast majority of the β-thalassemia mutations observed were CD26.

Status of screening for thalassemia and some related factors among pregnant women visiting the National Hospital of Obstetrics and Gynecology

This study aims to determine the current status of thalassemia and find out some related factors to screening of thalassemia in pregnant women visiting the hospital. Materials and Methods: a cross-sectional study, including quantitative and qualitative research. A total of 550 women who visited the hospital from April 2020 to March 2021 were screened by full blood count, hemoglobin electrophoresis, and thalassemia mutation test. In-depth interviews with 17 pregnant women to find out their awareness about some related factors to screening of thalassemia. Results: The prevalence of pregnant women screened positive for thalassemia was 12.7%. The α-thalassemia accounted for the largest proportion of 67.1%, the β-thalassemia form accounted for 12.9%. Hemoglobin E and other combinations have also been detected. Risk factors affected screening for thalassemia include ethnicity, obstetric history, and anemia status. Besides, family and socio-cultural factors also affected the decision of pregnant women. Most pregnant women didn’t know about thalassemia, so they were very nervous about the health of their fetuses and future births. Conclusion: From the above findings, awareness among pregnant women about thalassemia is still low, they do not pay attention to early screening for thalassemia. Therefore, it is necessary to raise awareness for pregnant women and their families about thalassemia disease.

Genetic Analysis and Prenatal Diagnosis of Thalassemia in Couples of Childbearing Age in Quanzhou Region Fujian Province, China

To explore the genotypes and prenatal diagnosis of thalassemia in couples of childbearing age in Quanzhou, Fujian Province. Blood routine and hemoglobin electrophoresis were performed for initial thalassemia screening in 76 328 couples in Quanzhou region from July 2017 to July 2020. The couples with positive initial screening results further underwent thalassemia gene test. Couples carrying homotypic thalassemia genes underwent prenatal diagnosis in the second trimester. Among 76 328 couples of childbearing age, 1 809 couples of positive initial thalassemia screening were identified, with the positive rate about 2.37%. Further results of genetic detection of the 1 809 couples showed that 985 cases were diagnosed as α- thalassemia, of which --sea/αα was the most frequency, followed by -α3.7/αα and ααQS/αα; 296 cases were diagnosed as β-thalassemia, the most frequency mutations were 654M/N and 41-42M/N; 26 cases of compound α and β-thalassemia were detected. In addition, 3 rare cases of thalassemia were detected, including --THAI/αα, SEA-HPFH, and -α6.9/--sea. Among them, 108 couples were confirmed as homologous thalassemia, with the detection rate about 5.97%, including 96 couples of homologous α-thalassemia, 9 couples of homologous β-thalassemia, and 3 couples with one had compound α- and β-thalassemia. Among them, 17 couples with homologous α-thalassemia underwent prenatal diagnosis in the second trimester, of which 1 case of Hb Bart's Hydrops Syndrome, 3 cases of HbH disease, 9 cases of silent thalassemia or α-thalassemia minor, and 4 cases of healthy fetuses were detected. Fetal chromosome karyotype analysis showed that 16 cases were normal and 1 case diagnosed as Down syndrome. Thalassemia screening in pre-marital and pre-pregnancy, and prenatal diagnosis can effectively reduce the birth of children with thalassemia intermediate and thalassemia major. It is necessary to perform chromosome karyotype analysis at the same time as prenatal diagnosis of thalassemia gene in order to avoid fetus with abnormal chromosome.

Genetic Analysis of Thalassemia in 22 940 Pregnant Women in Xiangxi Tujia and Miao Autonomous Prefecture

To investigate the incidence and types of thalassemia in Xiangxi Tujia and Miao Autonomous Prefecture. Automatic capillary electrophoresis was used to screen the thalassemia phenotypes of 22 940 blood samples of pregnant women and puerperants collected in our hospital and some other medical institutions in the prefecture during 2017-2019, among which there were 3 356 cases of Tujia ethnicity, 2 821 cases of Miao ethnicity, and 2 233 cases of Han ethnicity included, whose ethnicity were indicated. The samples with positive result would undergo further genetic testing. There were 2 314 cases of suspicious thalassemia were screened from 22 940 cases by the electrophoresis, thus the positive rate was 10.1% (hematological phenotypes from some other institutions were not included). Specifically, there were 1 706 cases with HBA2 less than 2.5%, 255 cases with HBA2 ranged from 2.5% to 3.5%, which displayed abnormal hematology (MCV or/and MCH) or other abnormal bands, and 353 cases with HBA2>3.5%. There were 436 suspected positive patients in 2 314 suspicious samples received further thalassemia gene testing in our hospital, among them 48 cases were diagnosed with α-thalassemia, 85 cases with β-thalassemia, and 2 cases as compound type. The positive diagnosis rate of α-thalassemia gene test was 11.0%, β-thalassemia was 19.4%, and positive pregnant women was 31.0%. The positive rate of thalassemia screening in Xiangxi Autonomous Prefecture is roughly the same as that in other regions of Hunan. The positive predictive value of β-thalassemia screening is as high as 86%. Compared with the missed screening data, it is recommended to use hematology (MCV, MCH) method combined with capillary hemoglobin electrophoresis for thalassemia screening.

A MALDI-TOF mass spectrometry-based haemoglobin chain quantification method for rapid screen of thalassaemia

Background Thalassaemia is one of the most common inherited monogenic diseases worldwide with a heavy global health burden. Considering its high prevalence in low and middle-income countries, a cheap, accurate and high-throughput screening test of thalassaemia prior to a more expensive confirmatory diagnostic test is urgently needed. Methods In this study, we constructed a machine learning model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains in blood, and for the first time, evaluated its diagnostic efficacy in 674 thalassaemia (including both asymptomatic carriers and symptomatic patients) and control samples collected in three hospitals. Parameters related to haemoglobin imbalance (α-globin, β-globin, γ-globin, α/β and α-β) were used for feature selection before classification model construction with 8 machine learning methods in cohort 1 and further model efficiency validation in cohort 2. Results The logistic regression model with 5 haemoglobin peak features achieved good classification performance in validation cohort 2 (AUC 0.99, 95% CI 0.98–1, sensitivity 98.7%, specificity 95.5%). Furthermore, the logistic regression model with 6 haemoglobin peak features was also constructed to specifically identify β-thalassaemia (AUC 0.94, 95% CI 0.91–0.97, sensitivity 96.5%, specificity 87.8% in validation cohort 2). Conclusions For the first time, we constructed an inexpensive, accurate and high-throughput classification model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains and demonstrated its great potential in rapid screening of thalassaemia in large populations. Key messages Thalassaemia is one of the most common inherited monogenic diseases worldwide with a heavy global health burden. We constructed a machine learning model based on MALDI-TOF mass spectrometry quantification of haemoglobin chains to screen for thalassaemia.

Exploring the Gap Between Knowledge and Behavior Regarding Thalassemia Among University Students: A Cross-Sectional Study in the United Arab Emirates.

Thalassemia is humanity's most common genetic disorder and represents a serious healthcare challenge in the United Arab Emirates. Increasing awareness is a crucial part of any successful strategy to prevent thalassemia. This research examined knowledge levels and attitudes regarding thalassemia screening, counseling, and monitoring from medical and nonmedical students at Ajman University. This was a cross-sectional, descriptive study conducted among a convenience sample of Ajman university students in the UAE. A questionnaire was distributed which was composed of three main sections. The first section covered participants' demographic data. The second section covered general knowledge of thalassemia and its screening measures. The third section assessed risk factors, regulations, and preventive measures. The data were analyzed using the statistical package for social sciences (SPSS) version 24. A total of 523 participants completed the whole survey. Generally, there was a good level of awareness of thalassemia and thalassemia screening among participants. Approximately three-quarters of participants (76.5%) agreed that thalassemia screening should be compulsory for the individual and the majority of students and 92.7% recognized the importance of thalassemia screening for both partners. Approximately three-quarters (75.9%) of participants disagreed that fetuses with thalassemia should be aborted. More than half of the participants disagreed that thalassemia carriers and patients should be prevented from marrying each other. Generally, older respondents (final year students), respondents who had dealt with thalassemia patients, and respondents with relatives with thalassemia had more comprehensive knowledge of thalassemia. Campaigns focusing on college and university students should be regarded as an essential element of the thalassemia prevention strategy for contemporary UAE society.

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

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. 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. 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. 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.

Molecular Epidemiology and Hematologic Characterization of Thalassemia in Guangdong Province, Southern China.

Introduction: About 2% of the population in the world are carriers of the thalassemia gene. Thalassemia is highly prevalent in Southern China, and traditional clinical testing methods would cause missed diagnosis of partial static thalassemia. Here, we reviewed and summarized a set of simple and clinically feasible thalassemia detection protocols adopted by the Prenatal Diagnosis and Reproductive Center of our hospital. Methods: From January 1, 2015, to December 31, 2020, 31 512 peripheral blood samples and 3828 prenatal samples were collected in our study. All the peripheral blood samples were performed through thalassemia screening by routine blood tests and hemoglobin electrophoresis and gene detection. The prenatal diagnosis would be implemented for the fetus if the parents were carriers of the same type of thalassemia. Results: A total of 6137 (19.48%) cases were diagnosed as thalassemia, in which 4749 (15.07%) were α-thalassemia, 1196 (3.80%) were β-thalassemia and 192 (0.61%) were co-inheritance of α- and β-thalassemia. For prenatal samples, 3160 (82.55%) cases were diagnosed as thalassemia, in which 2021 (52.80%) were α-thalassemia, 997 (26.05%) were β-thalassemia and 142 (3.71%) were co-inheritance of α- and β-thalassemia. In addition, we also found five novel mutations, including NC_000016.9:g.223681-227492del3812; HBA1: c.301-31_301-24delCTCGGCCCinsG; HBA2: c.95+7C>T for α-thalassemia and HBB: c.263_276delCACTGAGTGAGCTG; HBB: c.315+143G>A for β-thalassemia. Conclusion: The present study updates the epidemiological characteristics and mutation spectrum of thalassemia in Southern China and demonstrated five novel mutations. Our research provides a reference for clinical diagnosis and treatment, prenatal diagnosis, or reproductive genetic counseling for patients with thalassemia in Guangdong.

Knowledge, awareness and attitude of premarital screening sickle cell disease and thalassemia, Makkah, Saudi Arabia

Knowledge, awareness and attitude of premarital screening sickle cell disease and thalassemia, Makkah, Saudi Arabia