Prevention of homozygous beta thalassemia by premarital screening and prenatal diagnosis in India

Prevalence of beta thalassemia carriers in India: a systematic review and meta-analysis

A large number of studies have reported that the prevalence of beta thalassemia carriers in India varies by ethnic groups. The objective of this study was to conduct a systematic review of the published studies and conduct a meta-analysis to determine the prevalence of beta thalassaemia carriers in India. A PubMed database search using keywords "beta thalassaemia AND India" identified 1088 articles of which 69 articles were included in the review. Studies using diagnostic tests and methods recommended by the International Council for Standardization in Haematology were used for calculation of pooled prevalence. Pooled prevalence was calculated using a random effects model using Review Manager version 5.3. Studies had screened five categories of populations, that is, the general population; tribal groups, communities not belonging to tribal groups, persons with anemia, and persons referred with a suspicion of hemoglobinopathy. This heterogeneity contributed to a high pooled prevalence of beta thalassemia carriers of 8.23% (95% CI 7.36-9.10). Sub-group analysis however yielded 3.74% (95% CI 2.52-4.97) pooled prevalence of beta thalassemia carriers in the general population. It was 4.6% (95% CI 3.2-6.2) among tribal groups. Quality of prevalence studies was limited by methodological issues including non-random sampling methods, heterogeneity of population types screened, and lack of use of recommended diagnostic cut-offs. Prevalence of beta thalassemia carriers was similar in tribal populations and the general population, indicating the need to further investigate the prevalence of beta thalassemia carriers in tribal groups.

Genetic counseling in sickle cell disease: Insights from the Indian tribal population

Sickle cell disease (SCD) is an inherited disorder of hemoglobin. With an overall prevalence of 4.3%, India is the second-largest hub of SCD after Africa. Genetic counseling (GC) is the most cost-effective intervention to reduce the burden of a genetic disease including SCD. Even though GC's role in reducing SCD birth prevalence is well established, it is still not incorporated into Indian national policy and is unavailable to most Indians approaching their marriageable age and childbirth. GC perception and efficacy have also not been explored yet among young adults, especially in Indian tribal communities. Counseling in these communities requires careful consideration of their socioeconomic, cultural, and ethical values. Community engagement with local tribes and healthcare infrastructure in a multitier approach is essential for an effective GC. This review aims to provide healthcare providers and genetic counselors with the essentials of GC in the prevention and management of SCD among tribal communities based on the author's counseling experience in South India.

Knowledge and attitude of Engaged and Recently Married Couples Toward Premarital Screening: A Cross-Sectional Study

Background and Objective: Despite that inherited (thalassemia and SCA) and infectious (hepatitis B, hepatitis C and AIDs) diseases and their risk factor consanguineous marriage are widespread among Yemen population, community-based awareness studies towards premarital screening (PMS) is extremely limited, so our study is designed to elicit knowledge and attitude of engaged and recently married couples in Taiz (Yemen) toward PMS. Methods: A cross-sectional study was conducted from April to September 2021 at Taiz. A well-structured questionnaire was designed and then delivered to participants to collect data. Results: The results revealed that majority of respondents (83.60%-94.18%) had knowledge about inherited and infectious diseases, respectively, and educational institution was the main knowledge source. Females had significantly higher knowledge than males (P ≤ .01), except about AIDs since no difference (P = .539). The results also revealed that majority of respondents had positive attitudes toward PMS, except toward AIDs testing since 70% of males and 68.91% of females had negative attitudes. The majority of respondents agreed that screening reduces the diseases incidence. Approximately half of respondents (50.79%-56.61%) tend to go ahead for marriage in case of positive results for inherited and infectious diseases respectively. Making PMS as an obligatory step prior engagement was agreed by 47.62% of respondents (45.71% of males, 48.74% of females). Conclusion: A high level of knowledge and positive attitudes toward inherited and infectious diseases and PMS were reported. This knowledge reflected on the agreement of majority of respondents regarding PMS importance in term of reduction of diseases incidence.

Undiagnosed haemoglobinopathies among pregnant women attending antenatal care clinics in Pune, India

Pregnant women with iron deficiency and those who are carriers of haemoglobinopathies present with anaemia of varying severity. There is no antenatal screening for haemoglobinopathies in India. The objective of this study was to determine the prevalence of undiagnosed haemoglobinopathy carriers in a random sample of pregnant women attending antenatal care clinics in Pune city, India. Biobanked DNA of 360 randomly selected pregnant women was genotyped for six common mutations and two common haemoglobin variants, HbS and HbE. Odds ratios (OR) with 95% confidence intervals were computed to determine association of carrier status with socio-demographic, haematological and clinical characteristics. The prevalence of undiagnosed haemoglobinopathy carriers was 6.3% (95% CI 4.2-9.4%) of which 3.3% (95% CI 1.9-5.7%) were beta thalassaemia carriers. There was an increased odds that beta thalassaemia carriers had moderate anaemia (OR 10.59, 95% CI 1.15-96.90). This study reveals the high prevalence of undiagnosed haemoglobinopathy carriers among pregnant women, indicating the need to immediately implement carrier screening and genetic counselling services across the country.

The Changing Trends in Prenatal Diagnosis of Hemoglobinopathies in India: The Quest of a Single Center to Reduce the Burden of Disease over Three Decades

The β-thalassemias and sickle cell disorders pose a considerable health burden in India. Of the more than 10,000 annual births of children with a severe hemoglobinopathy, only around 10.0% are managed optimally. Thus, genetic counseling and prenatal diagnosis (PND) is a valid option for a large and diverse country. Our center was one of the first to initiate PND and we present our experience over 30 years to evaluate the impact of awareness in changing the trends of PND of hemoglobinopathies. Both second and first-trimester diagnoses were undertaken by fetoscopy/cordocentesis and globin biosynthesis/high-performance liquid chromatography (HPLC) analysis of fetal blood and chorionic villus sampling (CVS) and DNA analysis. Over 30 years, 3478 couples (first trimester: 2475; second trimester: 1003) from all over India were offered PND. The number of couples coming in the first trimester increased significantly over each decade and couples coming prospectively increased from 2.5 to 18.4%. A cost-effective stepwise approach was used for molecular analysis. Eight hundred and one fetuses (23.0%) were affected and all except three couples opted for termination of these pregnancies. Genetic counseling and PND is the only way to reduce the burden of disease. With awareness, there was a shift from second trimester to first trimester PND over each decade, with an increasing number of couples coming during the first pregnancy. There are only 15 to 20 centers in India offering PND. We have compared our study with other reports on PND from different regions in India.

Can RBC Indices be Used as Screening Test for Beta-Thalassemia in Indian Antenatal Women?

Objective

To determine the appropriateness of using MCV/MCH as screening test for beta-thalassemia trait in the present population and also to find the most appropriate cutoff for optimum sensitivity of these indices.

Methods

It was an analytical, observational and cross-sectional study. Complete blood count followed by high-performance liquid chromatography (HPLC) was performed. The MCV and MCH levels were noted in cases and controls.

Results

Thalassemia trait was found in 66 out of 1300 antenatal women with anemia. The MCV and MCH were significantly low in cases (p = 0.0001). MCV had a better AUC (0.650) than MCH (0.635). The most suitable cutoff value of MCV was calculated as 72 fl (sensitivity-63.7%, specificity-68.3%, PPV-9.7%, LR-2.0) and that for MCH was 24 pg (sensitivity-63.6%, specificity-59.4%, PPV-7.7%, LR-1.5) using Youden's index. When MCH (cutoff of 28 pg) and MCV were combined (cutoff of 74 fl), the sensitivity and specificity were 95% and 16%, respectively.

Conclusion

The sensitivity and specificity of MCV and MCH alone had low detection rate when used in combination had high sensitivity but the specificity was low; therefore, HPLC should be the preferred screening test for beta-thalassemia in Indian women.

Spectrum and hematological profile of hereditary anemia in North Indians: SGPGI experience

Thalassemia and other hemoglobinopathies together with red cell enzymopathies are a common cause of anemia, which can be prevented by population screening and genetic counseling. This study was designed to screen the anemic patients for thalassemia, structural hemoglobin variants and red cell enzymopathies. A total of 17047 cases were evaluated from 2009 to 2018 for thalassemia, hemoglobin variants, glucose 6 phosphate dehydrogenase deficiency, pyruvate kinase deficiency and hereditary spherocytosis. Patients' records were entered in a Microsoft excel sheet and a spectrum of disorders was evaluated. Year wise spectrum was also analyzed to see the difference in incidence at different time periods. Incidence of beta thalassemia trait and thalassemia major was found in 11.0% and 3.4% respectively, whereas other hemoglobinopathies were observed in 3.2% of the cases. G6PD deficient cases were 0.2 % and 0.4% had hereditary spherocytosis. No significant difference was observed in incidence of thalassemia and other hemoglobinopathies at different time points. This study provided a health burden and detailed spectrum and prevalence of hemoglobinopathies in North Indians high risk population which contribute toward the development of prevention strategies for better management of hemoglobinopathies. In view of high incidence of thalassemia a routine hematological screening at a primary health center may be introduced as a prospective premarital screening under a thalassemia control program. Moreover rapid and easy quantification of hemoglobin variants (Hb variants) make Cation exchange - High Performance Liquid Chromatography (CE-HPLC) a suitable diagnostic test for the routine investigation of genetic causes of anemia.

Population Screening for Hemoglobinopathies

Hemoglobinopathies are the most common single-gene disorders in the world. Their prevalence is predicted to increase in the future, and low-income hemoglobinopathy-endemic regions need to manage most of the world's affected persons. International organizations, governments, and other stakeholders have initiated national or regional prevention programs in both endemic and nonendemic countries by performing population screening for α- and β-thalassemia, HbE disease, and sickle cell disease in neonates, adolescents, reproductive-age adults (preconceptionally or in the early antenatal period), and family members of diagnosed cases. The main aim of screening is to reduce the number of affected births and, in the case of sickle cell disease, reduce childhood morbidity and mortality. Screening strategies vary depending on the population group, but a few common screening test methods are universally used. We discuss the salient features of population-screening programs around the globe as well as current and proposed screening test methodologies.

Monogenic diseases in India

Studies on monogenic diseases are considered valuable because they give insights and expand our knowledge on gene function and regulation. Despite all the current advancement in science and technology, a deep understanding and knowledge as to why only those particular genes are affected in a disease is still vague. We also lack profound illumination as to why only certain mutations are seen in a disease. Though useful from a research perspective, a majority of these diseases are lethal resulting in death of the affected individual. Unfortunately, in the fast - growing land of India, the incidence of monogenic diseases is very high with few counter-measures in place. This article encompasses a list of all monogenic diseases ever to be reported in India with special focus on five diseases which has been stated to have the highest incidence in India. Here, we discuss about the limited research carried out in India on these high incidence monogenic diseases, the other diseases related to those genes, the range of treatments available for these diseases in India in contrast to its availability around the world and the need to develop treatment strategies to reduce the mortality and morbidity due to these rare but daunting diseases.

Socio-demographic Profile and Economic Burden of Treatment of Transfusion Dependent Thalassemia

OBJECTIVE

To compile the socio-demographic profile and estimate the economic burden of transfusion dependent thalassemia.

METHODS

This cross-sectional descriptive study was conducted at a tertiary care hospital in north India. Transfusion dependent thalassemia patients on regular blood transfusion for at least a year were selected. Thalassemia diagnosis was based on HPLC and/or mutation analysis results. Clinical and laboratory parameters were collected from electronic health records. Information regarding socio-economic profile and costs incurred, including indirect costs were collected by interviewing patients' guardians. The data was analyzed as a whole cohort and also in subgroups based on age.

RESULTS

The data of 261 patients with a median age of 127 mo was collected. The median age at diagnosis was 9.8 mo. The total treatment expenses of a patient per year ranged from US$ 629 (INR 41,514) to US$ 2300 (INR 151,800), in the different age groups, at an average of US$ 1135 (INR 74,948). More than half (53%) of this was spent on medications. On an average, 38.8% of the family income was spent on the treatment of a thalassemia patient annually. Only 19 of 262 cases had an average pre-BT Hb ≥ 9 g/dl and serum ferritin ≤1500 ng/dl.

CONCLUSIONS

The treatment for transfusion dependent thalassemia is costly and mostly borne by the families in India. This study provides a realistic magnitude of this burden and will be useful in planning a thalassemia management program at the state or national level.

Key Pharmacogenomic Considerations for Sickle Cell Disease Patients

Sickle cell disease (SCD), although a monogenic disease, exhibits a complex clinical phenotype that hampers optimum patient stratification and disease management, especially on hydroxyurea treatment. Moreover, theranostics, the combination of diagnostics to individualize and optimize therapeutic interventions, has not been firmly on the forefront of SCD research and clinical management to date. We suggest that if tailor-made theranostics in SCD is envisaged, pharmacogenomics is anticipated to be the way forward. Herein, we present the current key pharmacogenomic opportunities and challenges in SCD, considering population variation, ethics, and socioeconomic aspects. We focus on pharmacogenomics and pain management, genethics, and cost-effectiveness in SCD. We searched for and synthesized data from PubMed and Google Scholar, and the references from relevant articles, using the keywords "pharmacogenomics," "sickle cell disease," "hydroxyurea," "ethics," "pain management," "morphine metabolism," "opioids," "pharmacogenomics and chronic pain," "cost-effectiveness," and "economic evaluation." Only articles published in English were included. So far, when pharmacogenomics in SCD has been considered, interindividual variability in hydroxyurea response/toxicity has been of primary interest. We underscore the need to extend pharmacogenomic considerations on other therapeutic interventions currently present using a holistic patient-centric approach, and taking disease complications into account as well. Furthermore, we raise awareness toward socioeconomic, ethical, and population differences in the way sickle cell pharmacogenomics might unfold in the future. If pharmacogenomics in SCD is to be used in the clinic in an evidence-based manner, cost-effectiveness and population-specific empirical ethics data are urgently needed.

Consequences of Delayed Prenatal Diagnosis of β-Thalassemia in Mainland China

β-Thalassemia (β-thal) is one of the most common inherited single gene disorders in the world. The aim of this study was to describe the gestational age at prenatal diagnosis (PND) for β-thal in at-risk women in mainland China. All pregnant women at-risk for β-thal and undergoing PND at a Mainland Chinese tertiary obstetric center between January 2005 and December 2014 were included. Information required for the survey was obtained from prenatal records and delivery charts. In total, 1307 women underwent PND for β-thal. The mean gestational age for the procedure was 18.5 weeks. There were 384 (29.0%) women with fetal diagnosis in early trimester (<14 weeks), 715 (55.0%) in early second trimester (14-24 weeks), and 208 (16.0%) in late second trimester or beyond (>24 weeks). Although the proportion of patients undergoing early PND increased along with the time span, the mean n gestational age was not decreased significantly during the study period. The delay in PND deprived couples of the opportunity to make informed decisions early in pregnancy.

Perspectives on Translational Genomics and Public Health in India

It is now recognized worldwide that anticipation and prevention of diseases have significant advantages for the health and healthy ageing of the population. Early recognition of the disease in a vulnerable population such as in children aged <5 years and adults aged >60 years enhances our preparedness for any eventualities and future burden of the diseases to society. It is also recognized that current public health practices alone cannot bring about the desired outcome. When tackling public health-related issues, such problems must be recognized and state-of-the-art principles and innovations from genomic sciences, information technologies, and medical specialties must be encompassed and embraced. These will enhance strategies for preparedness and provide us with a better understanding of how to identify, manage, and control disease burdens. The ever expanding landscape of genomics research also includes experimental and computational approaches for effectively utilizing DNA sequence information. From these perspectives, the intricacies of Mendelian single gene disorders are the least challenging compared to intricacies of multi-dimensional host factors for infectious diseases or complex disorders such as cancer. The concepts of public health in India are on firm footing; however, integration of contemporary advances to implement public health principles into practice has neither been attempted nor impacted on disease burden or our preparedness to prevent eventualities. At the same time, translational genomics is gradually paving the way for personalized medicine. Principles of personalized medicine remain to be fully understood and practiced despite the pharmacogenomics-based future of drug development, and treatment has not been as exciting as the advances in genomics we are witnessing today. The relevance, importance, and translational impediments of these advances will be discussed.

Control of Thalassemia in India

The β-thalassemias and sickle cell disorders pose a major health burden in the large and diverse Indian population. Education programs for awareness generation are being done by National Institutions, non-governmental organizations and Thalassemia Societies in different states. Several extensive epidemiological studies have shown that there are many non-tribal and tribal communities where the prevalence of b-thalassemia carriers is much higher (5.3 to 17.0%) than the average of 3 to 4% projected for the entire country. These variations have also been shown within small geographic regions in some states, emphasizing the need for micro mapping to estimate the true burden of disease. There are 10 to 12 centers where prenatal diagnosis for hemoglobinopathies is done and the Indian Council of Medical Research is establishing additional regional centers in states where they are most needed. Sixtyeight b-thalassemia mutations have been described so far among Indians and the knowledge on their prevalence and regional distribution has helped to undertake prenatal diagnosis in a cost effective way.

Preconception care: promoting reproductive planning

INTRODUCTION

Preconception care recognizes that many adolescent girls and young women will be thrust into motherhood without the knowledge, skills or support they need. Sixty million adolescents give birth each year worldwide, even though pregnancy in adolescence has mortality rates at least twice as high as pregnancy in women aged 20-29 years. Reproductive planning and contraceptive use can prevent unintended pregnancies, unsafe abortions and sexually-transmitted infections in adolescent girls and women. Smaller families also mean better nutrition and development opportunities, yet 222 million couples continue to lack access to modern contraception.

METHOD

A systematic review and meta-analysis of the evidence was conducted to ascertain the possible impact of preconception care for adolescents, women and couples of reproductive age on MNCH outcomes. A comprehensive strategy was used to search electronic reference libraries, and both observational and clinical controlled trials were included. Cross-referencing and a separate search strategy for each preconception risk and intervention ensured wider study capture.

RESULTS

Comprehensive interventions can prevent first pregnancy in adolescence by 15% and repeat adolescent pregnancy by 37%. Such interventions should address underlying social and community factors, include sexual and reproductive health services, contraceptive provision; personal development programs and emphasizes completion of education. Appropriate birth spacing (18-24 months from birth to next pregnancy compared to short intervals <6 months) can significantly lower maternal mortality, preterm births, stillbirths, low birth weight and early neonatal deaths.

CONCLUSION

Improving adolescent health and preventing adolescent pregnancy; and promotion of birth spacing through increasing correct and consistent use of effective contraception are fundamental to preconception care. Promoting reproductive planning on a wider scale is closely interlinked with the reliable provision of effective contraception, however, innovative strategies will need to be devised, or existing strategies such as community-based health workers and peer educators may be expanded, to encourage girls and women to plan their families.

Preconception care: delivery strategies and packages for care

The notion of preconception care aims to target the existing risks before pregnancy, whereby resources may be used to improve reproductive health and optimize knowledge before conceiving. The preconception period provides an opportunity to intervene earlier to optimize the health of potential mothers (and fathers) and to prevent harmful exposures from affecting the developing fetus. These interventions include birth spacing and preventing teenage pregnancy, promotion of contraceptive use, optimization of weight and micronutrient status, prevention and management of infectious diseases, and screening for and managing chronic conditions. Given existing interventions and the need to organize services to optimize delivery of care in a logical and effective manner, interventions are frequently co-packaged or bundled together. This paper highlights packages of preconception interventions that can be combined and co-delivered to women through various delivery channels and provides a logical framework for development of such packages in varying contexts.

Haemoglobinopathies in eastern Indian states: a demographic evaluation

Haemoglobinopathies are a leading cause of child mortality worldwide, although with a variable geographical incidence. A reliable estimate of prevalence of the disease is necessary for reducing its burden. However, most studies in India are either hospital based or from certain regions of the country and hence may not realistically reflect the disease burden. The eastern Indian states of Bihar, Chhattisgarh and Jharkhand and eastern region of Uttar Pradesh, which comprise ~25 % population of the country, are poorly studied with respect to haemoglobinopathies. The present study, conducted on 1,642 individuals from this region, shows a frequency of 3.4 % for β-thalassaemia trait (BTT), 3.4 % for sickle cell haemoglobin trait (HbS)/haemoglobin E trait (HbE) and 18 % for α-globin defects. While BTT mutations are distributed rather uniformly across the region, HbS occurs only in Chhattisgarh and Jharkhand, the regions rich in tribal populations. The frequency of α-gene mutation is strikingly high, occurring even in individuals with normal blood count, in tribal as well as non-tribal groups. The mutation spectrum of BTT is also distinct since the common mutations, IVS1-1 (G-T) and 619 bp del, are absent while CD15 (G-A) is the second most frequent. The HbA2 level in the suspected cases is strikingly low. We demonstrate association of the low HbA2 level with vitamin B12 and folate deficiency in this cohort. Thus, the present report besides providing an estimate of the carrier frequency of β-thalassaemia traits also confirms high prevalence of α-gene defects and regional heterogeneity in distribution of HbS in the eastern parts of India.

A Toolkit to assess health needs for congenital disorders in low- and middle-income countries: an instrument for public health action

BACKGROUND

In 2010 the World Health Assembly called for action to improve the care and prevention of congenital disorders, noting that technical guidance would be required for this task, especially in low- and middle-income countries. Responding to this call, we have developed a freely available web-accessible Toolkit for assessing health needs for congenital disorders.

METHODS

Materials for the Toolkit website (http://toolkit.phgfoundation.org) were prepared by an iterative process of writing, discussion and modification by the project team, with advice from external experts. A customized database was developed using epidemiological, demographic, socio-economic and health-services data from a range of validated sources. Document-processing and data integration software combines data from the database with a template to generate topic- and country-specific Calculator documents for quantitative analysis.

RESULTS

The Toolkit guides users through selection of topics (including both clinical conditions and relevant health services), assembly and evaluation of qualitative and quantitative information, assessment of the potential effects of selected interventions, and planning and prioritization of actions to reduce the risk or prevalence of congenital disorders.

CONCLUSIONS

The Toolkit enables users without epidemiological or public health expertise to undertake health needs assessment as a prerequisite for strategic planning in relation to congenital disorders in their country or region.

Clinicoinvestigational and demographic profile of children with thalassemia major

There are an estimated 200 million carriers of the β-thalassemia gene worldwide, 20 million being in India. The mean prevalence in India is 3.3 %. Objective To evaluate the clinico-investigational profile and the demographic characteristics of patients with thalassemia major (TM). Methods This was a retrospective analysis of the clinico-demographic profile at presentation of patients of TM diagnosed in the Paediatric Hematology Clinic of our hospital. Results The clinical profile of 964 patients of TM was analyzed. The mean age at presentation of untransfused children was 13.2 ± 9.7 months. Nearly 2/3(rd) children presented before 1 year of age. Almost 40 % had symptoms for 3 months prior to presentation. The manifestations at presentation included pallor and failure to thrive. About 40 % presented with severe anemia, with a hemoglobin of <5.0 gm/dl. A large number received blood transfusions prior to establishment of the diagnosis. Half of the families had ancestors who hailed originally from Pakistan. Approximately 50 % belonged to the Khatri/Arora castes. The parental literacy rate was about 90 %. Conclusions Thalassemia needs greater public awareness and prevention strategies in our country. Some communities are at high risk as compared to others. Education programs and compulsory antenatal screening appear to be the order of the day.

Analysis of β/α globin ratio by using relative qRT-PCR for diagnosis of beta-thalassemia carriers

BACKGROUND

Current routine tests for premarital screening of β-thalassemia carriers are not applicable for diagnosis of rare atypical minor β-thalassemia cases. A more specialized laboratory evaluation for them is the measurement of β/α chain synthesis ratio with the assistance of radioactive amino acids. This method is also no longer routinely accessible. Consequently it is required to establish a rapid, trouble-free, and reliable method that encompasses all the cases of β-thalassemia carriers. Therefore we have determined β/α-globin mRNA ratio by applying relative qRT-PCR in various β-thalassemia patients.

METHODS

Reticulocytes RNA extraction and subsequent cDNA synthesis were performed, followed by relative qRT-PCR for α- and β-globin chain genes and β-actin gene as an endogenous reference. β/α-Globin gene ratio was then evaluated with the Pfaffl method.

RESULTS

The mean of β/α ratio was 0.99, 0.81, 0.69, and 0.69 for normal population, minor, intermediate, and major β-thalassemia, respectively. Approximately 6% of cases with minor thalassemia RBC index and normal HbA2 and having a decreased β/α ratio were located in the minor β-thalassemia group. The mean of β/α mRNA ratio in normal individuals and minor β-thalassemia was significantly different with all other groups (P-value < 0.05). Nevertheless, there was no such association between β/α mRNA ratio in major and intermediate β-thalassemia.

CONCLUSION

According to the significant differences achieved, no overlapping between minor β-thalassemia and normal group, capability of diagnosing atypical minor β-thalassemia, and accessibility of this technique, we can declare that this method could be suggested as a routine premarital screening test for β-thalassemia carriers.

Proposed low-cost premarital screening program for prevention of sickle cell and thalassemia in Yemen

In Yemen, the prevalence of sickle cell trait and β-thalassemia trait are high. The aim of this premarital program is to identify sickle cell and thalassemia carrier couples in Yemen before completing marriages proposal, in order to prevent affected birth. This can be achieved by applying a low-cost premarital screening program using simple blood tests compatible with the limited health resources of the country. If microcytosis or positive sickle cell is found in both or one partner has microcytosis and the other has positive sickle cell, so their children at high risk of having sickle cell or/and thalassemia diseases. Carrier couples will be referred to genetic counseling. The outcomes of this preventive program are predicted to decrease the incidence of affected birth and reduce the health burden of these disorders. The success of this program also requires governmental, educational and religious supports.

The first five years of a preventive programme for haemoglobinopathies in Northeastern Iraq

OBJECTIVE

To evaluate the feasibility and effectiveness of a preventive programme for haemoglobinopathies in a single centre in Northeastern Iraq.

METHODS

Premarital screening, genetic counselling and prenatal diagnosis (PND) were implemented over a 5 year period.

RESULTS

Among a total of 108,264 screened individuals (54,132 couples), β-thalassaemia trait, δβ-thalassaemia trait, and sickle cell trait were diagnosed in 3.98%, 0.11% and 0.07%, respectively. Of 130 at risk couples (2.4/1000), 107 (82%) were available for follow up, with 105 couples (98.1%) proceeding with their marriage after counselling. In the 125 registered pregnancies in the latter couples, PND was performed in 85 (in 80 couples, uptake 76%). Selective termination was chosen in 10 of the 11 pregnancies with an affected fetus. Six affected babies were born among couples who declined PND. At the same time 30 already married couples with at least one thalassaemic child underwent PND, revealing three affected fetuses; all three pregnancies were terminated.

CONCLUSION

The programme revealed that most at risk couples diagnosed by premarital screening chose to proceed with their marriage, with 76% seeking PND followed by selective termination of an affected fetus. A 65% reduction in number of affected births was reported over the 5 year period. This regional programme could serve as a prototype for a national haemoglobinopathy prevention programme.

Prevalence of β-Thalassemia and hemoglobin E in two migrant populations of Manipur, North East India

Hemoglobinopathies are a group of inherited single-gene disorders found commonly in the Mediterranean region, Middle East, Indian subcontinent, Burma, and South East Asia. As many as 229 mutation variants of β-thalassemia are reported in the world, many community/region-specific mutations. Very little on thalassemia has been reported in Manipur, a North Eastern Indian state. Thus, a community genetic approach through population screening can be applied to the people of Manipur and a total of 602 blood samples from unrelated Meitei Brahmins (n=300) and Meitei Muslims (n=302) were screened for abnormal hemoglobins by Naked Eye Single Tube Red Cell Osmotic Fragility Test (NESTROFT). HBA(2) level was estimated by using high-performance liquid chromatography and molecular analysis was done by using PCR. Sequencing was also carried out to confirm the mutations. High frequencies of NESTROFT positive (10%) and NESTROFT doubtful (11%) cases were found among the Meitei Brahmins in comparison to the Meitei Muslims [NESTROFT positive (3.31%) and NESTROFT doubtful (1.33%)]. The allele frequency of HB*E was 0.022 and 0.012 among the Meitei Brahmin and Meitei Muslim, respectively. Sequencing of the β-globin gene confirmed a very rare β-thalassemia [-90 C→T (0.33%)] among the Meitei Brahmins of Manipur. This mutation with hemoglobin E in one of the present population hints the presence of the Mongoloid stock among them, possibly from China. There is a need for further studies on other populations of Manipur and the neighboring North East Indian states using such genetic markers.

Effectiveness of the model for prenatal control of severe thalassemia

OBJECTIVE

The aim of the research was to determine effectiveness of the model for prenatal control in reducing new cases of severe thalassemia.

METHODS

Pregnant women at six tertiary centers were recruited to follow the model, consisting of (1) carrier screening using mean corpuscular volume (for alpha-thal-1 and beta-thal) and CMU-E screen (for HbE trait), (2) carrier diagnosis, (3) the couples at risk were counseled and offered prenatal diagnosis, and (4) termination of affected pregnancy. All neonates were evaluated for thalassemia.

RESULTS

Of the 12,874 recruited pregnancies, 7008 were valid for analysis. Of them, 281 couples were identified to be at risk, Of the 281, 58 affected fetuses were identified and 55 pregnancies were terminated, whereas three did not accept pregnancy termination. All 6727 neonates at no risk were proven to be unaffected. The model had sensitivity and positive predictive value of 100% and 20%, respectively. The model could detect all of affected fetuses.

CONCLUSION

The model could prenatally identify affected fetuses with a detection rate and negative predictive value of 100%. The model was highly effective to prenatally detect affected fetuses with an acceptable false positive rate.

Factors influencing the decision to participate in medical premarital examinations in Hubei Province, Mid-China

Background

To investigate the attitudes of premarital couples towards the premarital screening program after the abolition of compulsory screening in China and to study the factors influencing participation.

Methods

Between July 1^st 2010 to August 31st 2010, 650 people who registered for marriage at the civil affairs bureau of Wuhan, Suizhou, Zaoyang in Hubei province were studied using questionnaires. Logistic regression was used to examine the factors influencing participation in the premarital screening program.

Results

The premarital screening rate was 34.8% (95% Confidence Interval: 31.0% to 38.5%). Several demographic factors (age, residence, profession), awareness, knowledge, and attitudes towards premarital screening all had significant influence on participation in the premarital screening program.

Conclusions

Promotion activities and health education to improve knowledge and attitudes to premarital screening will help increase the rate of voluntary premarital screening.

Preimplantation genetic diagnosis: recent triumphs and remaining challenges

Over the last 20 years, preimplantation genetic diagnosis (PGD) has changed from being an experimental procedure to one that is carried out in specialized diagnostic centers worldwide. Genetic awareness and the rapid identification of germline mutations or chromosomal abnormalities enable individuals to know their risk of transmitting a genetic disease before they have children. This has created a demand for PGD from couples who wish to avoid terminations of affected pregnancies. Although PGD is expensive because it requires couples to go through IVF, there is a trend for diagnosis to move towards automation, which will reduce cost and the need for specialized expertise. This will allow diagnosis to be carried out in routine molecular diagnostic laboratories.

Molecular basis and prenatal diagnosis of β-thalassemia among Balouch population in Iran

OBJECTIVE

To determine the molecular spectrum of β-thalassemia mutations among at-risk Balouch couples in Iran.

METHODS

Mutations' detection in DNAs extracted from the blood of partners of at-risk couples was characterized, and chorion villus sampling by amplification refractory mutation system and DNA sequencing was performed. Fetal diagnosis was also confirmed by linkage analysis.

RESULTS

Out of a total of 1234 at-risk Balouch couples referred to the center for prenatal diagnosis (PND) from June 2002 to June 2010, a high percentage of '67.4%' were from consanguineous marriages and 37.4% had between one and four affected children. The trend in referring gradually increased from 34 cases in 2002 to 357 cases in 2010. The astonishing finding was that, unlike most previous studies, only IVS 1-5 with an unusual frequency of 87.20% along with codon 8/9 (+G) with 4% constitutes about 91% of mutations. Altogether, 729 PNDs were made in 583 couples, 25% of whom had over one PND, and surprisingly five PNDs were made in the same woman within just 8 years.

CONCLUSION

Regarding the limited types of frequent mutations among Balouch population, it is hopefully believed that the incidence of β-thalassemia could be controlled by a correct diagnosis in the due time.

Six-year outcome of the national premarital screening and genetic counseling program for sickle cell disease and β-thalassemia in Saudi Arabia

BACKGROUND AND OBJECTIVES

Saudi Arabia has a high prevalence of hereditary hemoglobin disorders. Data has been collected by the Saudi Premarital Screening and Genetic Counseling Program on the prevalence of sickle cell disease and β-thalassemia but the outcomes were not quantified. We used six years of premarital screening data to estimate the burden of sickle disease and β-thalassemia over the program period and to assess the frequency of at-risk marriage detection and prevention.

DESIGN AND SETTING

Retrospective review, premarital couples attending premarital and genetic counseling clinics with marriage proposals between 2004 and 2009.

METHODS

Blood samples obtained from all couples with marriage proposals between 2004 and 2009 were tested for sickle cell disease and β-thalassemia. Test results were shared with all examinees and genetic counseling was offered for all at-risk couples. Marriage certificates were issued irrespective of the results and compliance with medical advice was voluntary.

RESULTS

Out of all men and women examined, 70,962 (4.5%) and 29,006 (1.8%) were carriers or cases of sickle cell disease and β-thalassemia, respectively. While the prevalence of sickle cell disease was constant between 2004 and 2009 (average 45.1 per 1000 examined persons, P=.803), the prevalence of β-thalassemia steadily decreased from 32.9 to 9.0 per 1000 examined persons (P<.001). The frequency of at-risk couples decreased by about 60% between 2004 and 2009 (from 10.1 to 4.0 per 1000 examined persons, P<.001). The frequency of voluntary cancellation of marriage proposals among at-risk couples showed more than 5-fold increase between 2004 and 2009 (from 9.2% to 51.9%, P<.001). The eastern region had 58% of all detected at-risk marriages and showed the greatest decline in detection and increase in prevention over time compared to other regions of Saudi Arabia.

CONCLUSION

Six years of premarital screening in Saudi Arabia markedly reduced the number of at-risk marriages, which may considerably reduce the genetic disease burden in Saudi Arabia in the next decades.

Bayesian estimates of the prevalence of β-thalassemia trait in voluntary blood donors of central India: a survey

Early detection of β-thalassemia (β-thal) trait is important. Voluntary blood donors represent an important group who are accessible and cooperative for this purpose. However, the usefulness of this population in β-thal trait detection programs has not been studied in India. We conducted a hematological survey of 5,045 blood donors who visited the Bhopal Memorial Hospital & Research Centre, Bhopal in central India. Using robust Bayesian methods, we estimated the prevalence of β-thal trait. The overall prevalence of β-thal trait in the study population was 9.59% [95% confidence interval (95% CI) 8.78-10.4%]. The prevalence of β-thal trait varied across the states of origin and within the state of Madhya Pradesh. We observed a cline effect for β-thal trait prevalence in relation to the latitude (p = 0.024). We conclude that blood donors offer an attractive adjunct to β-thal trait detection in national programs. Our study also offers insights into the β-thal trait gene flow and migration in India.

Prevention of severe thalassemia in northeast Thailand: 16 years of experience at a single university center

OBJECTIVE

To demonstrate the performance of thalassemia prevention in northeast Thailand during 1993-2008.

METHODS

Retrospective data from 1422 at-risk couples who attended from January 1993 to December 2008 were studied. All couples were suspected at-risk couples based on initial screening using standard protocols. Three thalassemia carrier types including alpha(0)-thalassemia, beta-thalassemia and hemoglobin E were identified using standard methods. Data on prenatal diagnosis were collected.

RESULTS

Of the 1422 positive-screened couples, 1254 (88.2%) were diagnosed as true-positive couples. After DNA analysis, 968 of 1254 (77.2%) resulted at risk for three types of severe conditions being hemoglobin E-beta-thalassemia disease (640/968, 66.1%), homozygous alpha(0)-thalassemia (304/968, 31.4%) and homozygous beta-thalassemia (11/968, 1.1%). The remaining 1.3% of the couples were at risk for more than one disease. After genetic counseling, prenatal diagnosis was performed on 756 couples (78.1%). The proportions of affected fetuses, thalassemia carriers and unaffected fetuses were 26.9, 50.0 and 23.0%, respectively.

CONCLUSION

Implementation of a prevention and control program accompanying with a referral system for prenatal diagnosis is technically feasible in northeast Thailand and a large number of severe thalassemia diseases have been prevented during the past 16 years of operation.

Profiling β-thalassaemia mutations in India at state and regional levels: implications for genetic education, screening and counselling programmes

Thalassaemia and sickle cell disease have been recognized by the World Health Organization as important inherited disorders principally impacting on the populations of low income countries. To create a national and regional profile of β-thalassaemia mutations in the population of India, a meta-analysis was conducted on 17 selected studies comprising 8,505 alleles and offering near-national coverage for the disease. At the national level 52 mutations accounted for 97.5% of all β-thalassaemia alleles, with IVSI-5(G>C) the most common disease allele (54.7%). Population stratification was apparent in the mutation profiles at regional level with, for example, the prevalence of IVSI-5(G>C) varying from 44.8% in the North to 71.4% in the East. A number of major mutations, such as Poly A(T>C), were apparently restricted to a particular region of the country, although these findings may in part reflect the variant test protocols adopted by different centres. Given the size and genetic complexity of the Indian population, and with specific mutations for β-thalassaemia known to be strongly associated with individual communities, comprehensive disease registries need to be compiled at state, district and community levels to ensure the efficacy of genetic education, screening and counselling programmes. At the same, time appropriately designed community-based studies are required as a health priority to correct earlier sampling inequities which resulted in the under-representation of many communities, in particular rural and socioeconomically under-privileged groups.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s11568-010-9132-3) contains supplementary material, which is available to authorized users.

Frequency of β-thalassemia trait and other hemoglobinopathies in northern and western India

INTRODUCTION

India is an ethnically diverse country with an approximate population of 1.2 billion. The frequency of beta-thalassemia trait (βTT) has variously been reported from <1% to 17% and an average of 3.3%. Most of these studies have been carried out on small population groups and some have been based on hospital-based patients. There is also a variation in the prevalence of hemoglobinopathies in different regions and population groups in the country. A high frequency of Hb D has been reported from the North in the Punjabi population, Hb E in the eastern region of India and Hb S is mainly reported from populations of tribal origin from different parts of the country.

OBJECTIVES

To study the gene frequency of βTT and other hemoglobinopathies in three regions East (Kolkata), West (Mumbai) and North (Delhi) in larghe population group (schoolchildren) for a more accurate assessment of gene frequency for planning of control programmes for haemoglobinopathies.

MATERIALS AND METHODS

This study included 5408 children from 11 schools in Delhi, 5682 from 75 schools in Mumbai and 957 schoolchildren from Kolkata who were screened for βTT and haemoglobinopathies. These included 5684 children from 75 schools in Mumbai and 5408 children from 11 schools in Delhi. Children were 11-18 years of age of both sexes. The final report is, however, only on 11090 schoolchildren from Mumbai and Delhi as data from Kolkata was restricted both in numbers and objectives and could not be included for comparison.

RESULTS

The overall gene frequency of βTT in Mumbai and Delhi was 4.05% being 2.68% and 5.47% in children of the two cities respectively. In Mumbai, the gene frequency was evenly distributed. Majority of the children with βTT from Mumbai were from Marathi (38.9%) and Gujarati (25%) speaking groups. Gene frequency was >5% in Bhatias, Khatris, Lohanas and Schedule Castes. In Delhi, a higher incidence was observed in schoolchildren of North and West Delhi (5.8-9.2%). The schoolchildren of North and West Delhi comprised predominantly of Punjabi origin compared to children in the South of the city (2.2%, 2.3%). When analyzed state-wise, the highest incidence was observed in children of Punjabi origin (7.6%) and was >4% from several other states. Majority of the traits from Mumbai were anemic (95.1% male and 85.6% in female). The prevalence of anemia was lower (62.7% male and 58.4% female) children with βTT from Delhi. This was a reflection of the higher prevalence of anemia in children without hemoglobinopathy in Mumbai than in Delhi. Nutritional deficiency was probably more severe and rampant in children Mumbai. Gene frequency of Hb D was greater in schoolchildren from Delhi (1.1%) than in Mumbai (0.7%). Hb S trait (0.2%) was observed exclusively in children from Mumbai. A low incidence of Hb E trait (0.04%) was seen in children in Mumbai. A higher incidence is reported from the East. The number of cases studied from the eastern region was small as the data from the East (Kolkata) could not be included in the analysis.

CONCLUSION

This study comprises a larger number of children studied for the gene frequency of βTT and other hemoglobinopathies from India. Population groups with higher gene frequencies require screening programmes and facilities for antenatal diagnosis as well as increased awareness and educational programmes to control the birth of thalassemic homozygotes. The overall carrier frequency of βTT was 4.05% and reinforces the differential frequency of β-thalassemia trait in schoolchildren from Delhi and Mumbai and the higher incidence of hemoglobin D in Punjabis as reported previously. The birth incidence calculated thereof for homozygous thalassemics would be 11,316 per year which are added each year to the existing load of homozygous thalassemics. This is much higher than the previously reported number of births annually. Hence suitable control measures need to be undertaken urgently in India.