A review of key terminology and definitions used for birth defects globally

Birth defects, also known as congenital disorders, are a significant health issue impacting at least five million births annually worldwide. For policymakers to mount a relevant healthcare response to care for those affected, the burden of disease of these conditions must be quantified. Estimates of the contribution of birth defects to under-5 child mortality and morbidity are generated by several groups globally. These estimates often differ, causing confusion for policymakers. While some differences may be attributed to the data sources and methods used, much is due to a lack of clarity in the terminology used for the group of disorders classed as "congenital". This study aimed to gain insight into the diversity of terms and definitions for birth defects, including those used routinely by relevant international/national organisations and in the peer-reviewed literature. This two-part study included (1) scoping review of peer-reviewed literature to identify terms and definitions in use for birth defects and (2) review of key websites and grey literature to identify terms and definitions used. The results of this study indicate a wide variety of terms being used, often interchangeably and undefined, in peer-reviewed publications, on institutional websites and related literature. This suggests a lack of clarity related to terminology and sets the scene for further discussion, recommending that the community of practice working on birth defects comes to a consensus on standard terminology and definitions for global uptake and implementation. Such standardisation will facilitate a common understanding of the burden of these disorders globally, regionally and within countries so that action can be taken to support affected children and their families.

Modelled epidemiological data for selected congenital disorders in South Africa

Congenital disorders (CD) remain an unprioritized health care issue in South Africa with national surveillance underreporting by > 95%. This lack of empiric data contributes to an underestimation of the CD disease burden, resulting in a lack of services for those affected. Modelling offers estimated figures for policymakers to plan services until surveillance is improved. This study applied the Modell Global Database (MGDb) method to quantify the South African CD disease burden in 2012. The MGDb combines birth prevalence data from well-established registries with local demographic data to generate national baseline estimates (birth prevalence and outcomes) for specific early-onset, endogenous CDs. The MGBd was adapted with local South African demographic data to generate baseline (no care) and current care national and provincial estimates for a sub-set of early-onset endogenous CDs. Access to care/impact of interventions was quantified using the infant mortality rate as proxy. With available care in 2012, baseline birth prevalence (27.56 per 1000 live births, n = 32,190) decreased by 7% with 2130 less affected births, with 5400 (17%) less under-5 CD-related deaths and 3530 (11%) more survivors at 5 years, including 4720 (15%) effectively cured and 1190 (4%) less living with disability. Results indicate a higher proportion of CD-affected births than currently indicated by national surveillance. By offering evidence-based estimates, the MGDb may be considered a tool for policymakers until accurate empiric data becomes available. Further work is needed on key CD groups and costing of specific interventions.

The Prevention of Thalassemia Revisited: A Historical and Ethical Perspective by the Thalassemia International Federation

Hemoglobinopathies are the most common monogenic disorders in humans; among them, thalassemia constitutes a serious medical and public health problem in high prevalence regions, in a geographical zone ranging from the Mediterranean Basin to China. In addition, migrations over the years have introduced thalassemia to many parts of the world. Although disease-specific programs are in place and accessible to most patients in prosperous countries, this is not the case in developing economies, where more than 75.0% of the patient population is born and lives; this concerns both prevention and treatment programs. In view of the significant improvements in public health and healthcare systems over the past few years, the Thalassemia International Federation has revisited the thalassemia prevention programs, initiatives and policies in some of its member countries, discussing their effectiveness and whether any changes in policy or public attitudes to thalassemia prevention have occurred through the recent years.

Chromosomal disorders: estimating baseline birth prevalence and pregnancy outcomes worldwide

Chromosomal disorders, of which Down syndrome is the most common, can cause multi-domain disability. In addition, compared to the general population, there is a higher frequency of death before the age of five. In many settings, large gaps in data availability have hampered policy-making, programme priorities and resource allocation for these important conditions. We have developed methods, which overcome this lack of data and allow estimation of the burden of affected pregnancies and their outcomes in different settings worldwide. For example, the methods include a simple equation relating the percentage of mothers 35 and over to Down syndrome birth prevalence. The results obtained provide a starting point for consideration of services that can be implemented for the care and prevention of these disorders.

Estimating the birth prevalence and pregnancy outcomes of congenital malformations worldwide

Congenital anomaly registries have two main surveillance aims: firstly to define baseline epidemiology of important congenital anomalies to facilitate programme, policy and resource planning, and secondly to identify clusters of cases and any other epidemiological changes that could give early warning of environmental or infectious hazards. However, setting up a sustainable registry and surveillance system is resource-intensive requiring national infrastructure for recording all cases and diagnostic facilities to identify those malformations that that are not externally visible. Consequently, not all countries have yet established robust surveillance systems. For these countries, methods are needed to generate estimates of prevalence of these disorders which can act as a starting point for assessing disease burden and service implications. Here, we describe how registry data from high-income settings can be used for generating reference rates that can be used as provisional estimates for countries with little or no observational data on non-syndromic congenital malformations.

Historical overview of development in methods to estimate burden of disease due to congenital disorders

Congenital disorders (often also called birth defects) are an important cause of mortality and disability. They encompass a wide range of disorders with differing severity that can affect any aspect of structure or function. Understanding their epidemiology is important in developing appropriate services both for their prevention and treatment. The need for epidemiological data on congenital disorders has been recognised for many decades. Here, we provide a historical overview of work that has led to the development of the Modell Global Database of Congenital Disorders (MGDb)—a tool that can be used to generate evidence-based country, regional and global estimates of the birth prevalence and outcomes of congenital disorders.

Rare single gene disorders: estimating baseline prevalence and outcomes worldwide

As child mortality rates overall are decreasing, non-communicable conditions, such as genetic disorders, constitute an increasing proportion of child mortality, morbidity and disability. To date, policy and public health programmes have focused on common genetic disorders. Rare single gene disorders are an important source of morbidity and premature mortality for affected families. When considered collectively, they account for an important public health burden, which is frequently under-recognised. To document the collective frequency and health burden of rare single gene disorders, it is necessary to aggregate them into large manageable groupings and take account of their family implications, effective interventions and service needs. Here, we present an approach to estimate the burden of these conditions up to 5 years of age in settings without empirical data. This approaches uses population-level demographic data, combined with assumptions based on empirical data from settings with data available, to provide population-level estimates which programmes and policy-makers when planning services can use.

Methods to estimate access to care and the effect of interventions on the outcomes of congenital disorders

In the absence of intervention, early-onset congenital disorders lead to pregnancy loss, early death, or disability. Currently, lack of epidemiological data from many settings limits the understanding of the burden of these conditions, thus impeding health planning, policy-making, and commensurate resource allocation. The Modell Global Database of Congenital Disorders (MGDb) seeks to meet this need by combining general biological principles with observational and demographic data, to generate estimates of the burden of congenital disorders. A range of interventions along the life course can modify adverse outcomes associated with congenital disorders. Hence, access to and quality of services available for the prevention and care of congenital disorders affects both their birth prevalence and the outcomes for affected individuals. Information on this is therefore important to enable burden estimates for settings with limited observational data, but is lacking from many settings. This paper, the third in this special issue on methods used in the MGDb for estimating the global burden of congenital disorders, describes key interventions that impact on outcomes of congenital disorders and methods used to estimate their coverage where empirical data are not available.

Estimates of global and regional prevalence of neural tube defects for 2015: a systematic analysis

Neural tube defects (NTDs) are associated with substantial mortality, morbidity, disability, and psychological and economic costs. Many are preventable with folic acid, and access to appropriate services for those affected can improve survival and quality of life. We used a compartmental model to estimate global and regional birth prevalence of NTDs (live births, stillbirths, and elective terminations of pregnancy) and subsequent under-5 mortality. Data were identified through web-based reviews of birth defect registry databases and systematic literature reviews. Meta-analyses were undertaken where appropriate. For 2015, our model estimated 260,100 (uncertainty interval (UI): 213,800-322,000) NTD-affected birth outcomes worldwide (prevalence 18.6 (15.3-23.0)/10,000 live births). Approximately 50% of cases were elective terminations of pregnancy for fetal anomalies (UI: 59,300 (47,900-74,500)) or stillbirths (57,800 (UI: 35,000-88,600)). Of NTD-affected live births, 117,900 (∼75%) (UI: 105,500-186,600) resulted in under-5 deaths. Our systematic review showed a paucity of high-quality data in the regions of the world with the highest burden. Despite knowledge about prevention, NTDs remain highly prevalent worldwide. Lack of surveillance and incomplete ascertainment of affected pregnancies make NTDs invisible to policy makers. Improved surveillance of all adverse outcomes is needed to improve the robustness of total NTD prevalence estimation, evaluate effectiveness of prevention through folic acid fortification, and improve outcomes through care and rehabilitation.

An overview of concepts and approaches used in estimating the burden of congenital disorders globally

Congenital disorders are an important cause of pregnancy loss, premature death and life-long disability. A range of interventions can greatly reduce their burden, but the absence of local epidemiological data on their prevalence and the impact of interventions impede policy and service development in many countries. In an attempt to overcome these deficiencies, we have developed a tool—The Modell Global Database of Congenital Disorders (MGDb) that combines general biological principles and available observational data with demographic data, to generate estimates of the birth prevalence and effects of interventions on mortality and disability due to congenital disorders. MGDb aims to support policy development by generating country, regional and global epidemiological estimates. Here we provide an overview of the concepts and methodological approach used to develop MGDb.

Systematic Review and Meta-Analysis of the Birth Prevalence of Orofacial Clefts in Low- and Middle-Income Countries

BACKGROUND

In the last comprehensive review of the literature published in 2002, little information on the prevalence of orofacial clefts was available from low- and middle-income countries (LMICs).

OBJECTIVE

To analyze published data on the birth prevalence of cleft lip and/or palate (CL/P) from LMIC.

DESIGN

Systematic review of the literature and meta-analysis of data from original papers on the birth prevalence of cleft lip and/or cleft palate (CL/P) in LMICs between 1990 and 2014. Secondary inclusion criteria were developed to analyze lower-quality studies from countries with scarce data.

MAIN OUTCOME MEASURE

Birth prevalence of undifferentiated CL/P (with or without associated syndrome or other anomaly).

RESULTS

Twenty-eight studies met strict inclusion criteria. Among 31,475,278 total births, the pooled birth prevalence of undifferentiated CL/P was 1.38 per 1000 births (95% confidence interval [CI]: 1.20 to 1.56). Four studies met criteria for secondary analysis, providing data on 75,627 births, with a pooled prevalence of 0.75 CL/P cases per 1000 births (95% CI: 0.56 to 0.95). Comparison of studies was limited by variable definitions of cases and of the reference population and by inconsistent reporting of outcomes. There is significant heterogeneity in the findings.

CONCLUSIONS

In LMICs, approximately 1 in every 730 children is born with CL/P. To optimize comparability across settings, future research should use a standard classification system and standard criteria for data collection and presentation. As clefting is associated with deprivation, understanding the true scale, risks, and preventive measures for orofacial clefts in LMIC is a matter of both scientific and humanitarian importance.

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.

Examining the family-centred approach to genetic testing and counselling among UK Pakistanis: a community perspective

WHO advice suggests a family-centred approach for managing the elevated risk of recessively inherited disorders in consanguineous communities, whilst emerging policy recommends community engagement as an integral component of genetic service development. This paper explores the feasibility of the family-centred approach in the UK Pakistani origin community. The study took place within a context of debate in the media, professional and lay circles about cousin marriage causing disability in children. Using qualitative methods, a total of six single-sex focus group discussions (n = 50) were conducted in three UK cities with a high settlement of people of Pakistani origin. Tape-recorded transcripts were analysed using framework analysis. Kinship networks within Pakistani origin communities are being sustained and marriage between close blood relatives continues to take place alongside other marriage options. Study participants were critical of what was perceived as a prevalent notion that cousin marriage causes disability in children. They were willing to discuss cousin marriage and disability, share genetic information and engage with genetic issues. A desire for accurate information and a public informed about genetic issues was articulated whilst ineffective communication of genetic risk information undermined professionals in their support role. This study suggests a community that is embracing change, one in which kinship networks are still active and genetic information exchange is taking place. At the community level, these are conditions supportive of the family-centred approach to genetic testing and counselling.

Falling prevalence of beta-thalassaemia and eradication of malaria in the Maldives

Carriers of haemoglobin disorders have protection against falciparum malaria. Therefore, where this is common, carrier prevalence rises until this selective advantage is offset by deaths of affected children. Theory predicts a corresponding fall in carrier frequency following malaria eradication, but this has not been reported in practice. In the Maldives, malaria eradication (in 1972-1975) unmasked highly prevalent beta-thalassaemia and led to services for patient care and outreach carrier screening. Analysis of 68,986 laboratory screening records for subjects born between 1960 and 1990 showed carrier prevalences ranging from 10.1% to 28.2% by atoll (related to the prevalence of falciparum malaria before eradication) and a steady fall in average carrier prevalence from 21.3% among those born in 1970 to 16% in those born in 1989. Data for individuals born before 1970 suggest that earlier, when malaria was uncontrolled, carrier prevalence was 23-25%. The observed fall in carrier prevalence was broadly consistent with a model based on genetic theory, allowing for the heterogeneous distribution of carrier prevalence and the potential contribution of consanguineous marriage. The possible effects of population mixing and reproductive compensation were calculated, and any contribution to falling carrier prevalence was excluded. It is concluded that the observed fall in thalassaemia carrier prevalence in the Maldives is consistent with the predicted effect of malaria eradication and supportive of the population genetic theory. The observed fall in average carrier prevalence corresponds to a fall in minimum affected birth prevalence from approximately 12/1,000 in 1970 to approximately 6.9/1,000 in 2007. Allowing for this effect, the National Thalassaemia Register has documented a more than 60% fall in affected birth prevalence since outreach population screening was established in 1997. The main contributing factors are considered to be limitation of final family size by informed at-risk couples and utilisation of prenatal diagnosis.

Folic acid to reduce neonatal mortality from neural tube disorders

Background Neural tube defects (NTDs) remain an important, preventable cause of mortality and morbidity. High-income countries have reported large reductions in NTDs associated with folic acid supplementation or fortification. The burden of NTDs in low-income countries and the effectiveness of folic acid fortification/supplementation are unclear.

Objective To review the evidence for, and estimate the effect of, folic acid fortification/supplementation on neonatal mortality due to NTDs, especially in low-income countries.

Methods We conducted systematic reviews, abstracted data meeting inclusion criteria and evaluated evidence quality using adapted Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. Where appropriate, meta-analyses were performed.

Results Meta-analysis of three randomized controlled trials (RCTs) of folic acid supplementation for women with a previous pregnancy with NTD indicates a 70% [95% confidence interval (CI): 35–86] reduction in recurrence (secondary prevention). For NTD primary prevention through folic acid supplementation, combining one RCT with three cohort studies which adjusted for confounding, suggested a reduction of 62% (95% CI: 49–71). A meta-analysis of eight population-based observational studies examining folic acid food fortification gave an estimated reduction in NTD incidence of 46% (95% CI: 37–54). In low-income countries an estimated 29% of neonatal deaths related to visible congenital abnormalities are attributed to NTD. Assuming that fortification reduces the incidence of NTDs, but does not alter severity or case-fatality rates, we estimate that folic acid fortification could prevent 13% of neonatal deaths currently attributed to congenital abnormalities in low-income countries.

Discussion Scale-up of periconceptional supplementation programmes is challenging. Our final effect estimate was therefore based on folic acid fortification data. If folic acid food fortification achieved 100% population coverage the number of NTDs in low-income countries could be approximately halved.

Conclusion The evidence supports both folic acid supplementation and fortification as effective in reducing neonatal mortality from NTDs.

A Different Molecular Pattern of β‐Thalassemia Mutations in Northeast Brazil

The main hereditary hemoglobin (Hb) disorders of clinical significance in Brazil are sickle cell disease and beta-thalassemia (thal). The sickle gene was introduced by the slave trade, whereas beta-thal was introduced later, due to a massive immigration (mostly by Italians) between 1870 and 1953, mainly to the southeast region of Brazil. Molecular studies performed in the southeast of the country showed a marked prevalence of the nonsense mutation at codon 39 (C --> T) (47-54%), leading to severe forms of beta0-thal. However, the northeast region of the country has a different demographic history, characterized by the absence of the massive Italian immigration. Owing to this and since the majority of cases of beta-thal in Pernambuco, a state located in the northeast of the country, have mild or intermediate clinical and laboratory features, we would predict a different spectrum of beta-thal mutations in this region. We examined 60 unrelated patients (86 beta-thal chromosomes) under regular clinical follow-up in Pernambuco: 6 were regularly transfused beta-thal major subjects, 20 had beta-thal intermedia, 20 had Hb S/beta-thal and 14 were beta-thal trait individuals. The following mutations were found: IVS-I-6 (T --> C) 62.8%, IVS-I-1 (G -->A) 15.1%, IVS-I-5 (G --> C) 9.3%, IVS-I-110 (G --> A) 8.2%, codon 39 (C --> T) 3.5%, and codon 30 (AGG --> AGC) 1.1%. These data show different patterns of beta-thal mutations in two regions of Brazil, demonstrating a thus far unrevealed heterogeneity of the disease in the country.

Deferasirox for the treatment of iron overload associated with regular blood transfusions (transfusional haemosiderosis) in patients suffering with chronic anaemia: a systematic review and economic evaluation

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of deferasirox for the treatment of iron overload associated with regular blood transfusions in patients with chronic anaemia such as beta-thalassaemia major (beta-TM) and sickle cell disease (SCD).

DATA SOURCES

Electronic databases were searched up to March 2007.

REVIEW METHODS

Methods followed accepted procedures for conducting and reporting systematic reviews and economic evaluations.

RESULTS

A total of 14 randomised controlled trials (RCTs) involving a study population of 1480 (ranging from 13 to 586) met the inclusion criteria. There was a high degree of heterogeneity between trials in terms of trial design and outcome reporting. As such it was only possible to meta-analyse serum ferritin data from six trials making comparisons between deferiprone and DFO and combination therapy and DFO. Only one of the results was statistically significant, favouring combination therapy over DFO alone for serum ferritin at 12 months. How this translates into iron loading in organs such as the heart is unclear, nor was it possible to determine the long-term benefits of chelation therapy. Eight full economic evaluations (one full paper; seven abstracts) were included in the review. The results were generally consistent and appear to demonstrate the cost-effectiveness of deferasirox compared with DFO for the treatment of iron overload in a number of different patient populations and study locations. However, a number of assumptions and, in the case of the long-term studies, extrapolation from short-term RCT data were required, which render the results highly speculative at best. Because of the paucity of long-term data we developed a simple, short-term (1 year) model to assess the costs and benefits of deferasirox, deferiprone and DFO in patients with beta-TM and SCD from an NHS perspective. A number of assumptions were required to generate results and, as such, they should be interpreted as indicative rather than factual. Our model suggests that deferasirox may be a cost-effective strategy compared with DFO, at a cost per quality-adjusted life-year (QALY) below 30,000 pounds per year, for patients with beta-TM and SCD. However, this is highly dependent upon the age of the patient and the use and benefits of balloon infusers to administer DFO. Deferasirox compared with deferiprone is likely to be cost-effective only for young children. Furthermore, if deferiprone is proven to offer the same health benefits as deferasirox, the latter will not be cost-effective for any patient compared with deferiprone.

CONCLUSIONS

In the short term there is little clinical difference between any of the three chelators in terms of removing iron from the blood and liver. Deferasirox may be cost-effective compared with DFO in patients with beta-TM and SCD, but it is unlikely to be cost-effective compared with deferiprone. Elucidating the long-term benefits of chelation therapy, including issues of adverse events and adherence, should be the primary focus for future research. Future work should aim for consistency and transparency in reporting study design and results to aid decision-making when making comparisons across trials.

Improved survival of thalassaemia major in the UK and relation to T2* cardiovascular magnetic resonance

BACKGROUND

The UK Thalassaemia Register records births, deaths and selected clinical data of patients with thalassaemia who are resident in the UK. A study of survival and causes of death was undertaken which aimed to include the possible impact of T2* cardiovascular magnetic resonance (CMR).

METHODS

The Register was updated to the end of 2003, copies of death certificates were obtained, and causes of death in beta thalassaemia major were extracted. In addition, patients who had T2* CMR assessment of cardiac iron load and/or received the oral iron chelator deferiprone were identified from clinical records.

RESULTS

The main causes of death were anaemia (before 1980), infections, complications of bone marrow transplantation and cardiac disease due to iron overload. From 1980 to 1999 there were 12.7 deaths from all causes per 1,000 patient years. Forty per cent of patients born before 1980 had T2* cardiovascular magnetic resonance between 2000 and 2003, and 36% of these patients were prescribed deferiprone before end of 2003. In 2000-2003, the death rate from all causes fell significantly to 4.3 per 1,000 patient years (-62%, p < 0.05). This was mainly driven by the reduction in the rate of deaths from iron overload which fell from 7.9 to 2.3 deaths per 1,000 patient years (-71%, p < 0.05).

CONCLUSION

Since 1999, there has been a marked improvement in survival in thalassaemia major in the UK, which has been mainly driven by a reduction in deaths due to cardiac iron overload. The most likely causes for this include the introduction of T2* CMR to identify myocardial siderosis and appropriate intensification of iron chelation treatment, alongside other improvements in clinical care.

Improved survival of thalassaemia major in the UK and relation to T2* cardiovascular magnetic resonance

BACKGROUND

The UK Thalassaemia Register records births, deaths and selected clinical data of patients with thalassaemia who are resident in the UK. A study of survival and causes of death was undertaken which aimed to include the possible impact of T2* cardiovascular magnetic resonance (CMR).

METHODS

The Register was updated to the end of 2003, copies of death certificates were obtained, and causes of death in beta thalassaemia major were extracted. In addition, patients who had T2* CMR assessment of cardiac iron load and/or received the oral iron chelator deferiprone were identified from clinical records.

RESULTS

The main causes of death were anaemia (before 1980), infections, complications of bone marrow transplantation and cardiac disease due to iron overload. From 1980 to 1999 there were 12.7 deaths from all causes per 1,000 patient years. Forty per cent of patients born before 1980 had T2* cardiovascular magnetic resonance between 2000 and 2003, and 36% of these patients were prescribed deferiprone before end of 2003. In 2000-2003, the death rate from all causes fell significantly to 4.3 per 1,000 patient years (-62%, p < 0.05). This was mainly driven by the reduction in the rate of deaths from iron overload which fell from 7.9 to 2.3 deaths per 1,000 patient years (-71%, p < 0.05).

CONCLUSION

Since 1999, there has been a marked improvement in survival in thalassaemia major in the UK, which has been mainly driven by a reduction in deaths due to cardiac iron overload. The most likely causes for this include the introduction of T2* CMR to identify myocardial siderosis and appropriate intensification of iron chelation treatment, alongside other improvements in clinical care.

Global epidemiology of haemoglobin disorders and derived service indicators

To demonstrate a method for using genetic epidemiological data to assess the needs for equitable and cost-effective services for the treatment and prevention of haemoglobin disorders. We obtained data on demographics and prevalence of gene variants responsible for haemoglobin disorders from online databases, reference resources, and published articles. A global epidemiological database for haemoglobin disorders by country was established, including five practical service indicators to express the needs for care (indicator 1) and prevention (indicators 2-5). Haemoglobin disorders present a significant health problem in 71% of 229 countries, and these 71% of countries include 89% of all births worldwide. Over 330,000 affected infants are born annually (83% sickle cell disorders, 17% thalassaemias). Haemoglobin disorders account for about 3.4% of deaths in children less than 5 years of age. Globally, around 7% of pregnant women carry b or a zero thalassaemia, or haemoglobin S, C, D Punjab or E, and over 1% of couples are at risk. Carriers and at-risk couples should be informed of their risk and the options for reducing it. Screening for haemoglobin disorders should form part of basic health services in most countries.

Microcytosis, iron deficiency and thalassaemia in a multi-ethnic community: a pilot study

The high prevalence of microcytosis (defined here as mean cell haemoglobin<27 pg) with no other abnormality is a principal cause of confusion in screening for haemoglobin disorders. Here we report the results of a small pilot study aiming to resolve this confusion by routinely proceeding to plasma ferritin and HPLC assay, using the original sequestrene blood sample, when microcytosis is detected. Participants comprised a random sample of 1,302 people referred for a full blood count by their General Practitioner (GP) to the laboratory of a North London district general hospital serving a multi-ethnic inner-city population. Ethnicity was established by questionnaire. In North Europeans, microcytosis was present in 3% of males (half were iron-deficient) and 11% of females (most were iron-deficient). Among ethnic minorities, microcytosis was present in 35% of males (one tenth were iron-deficient), and 45% of females (less than half were iron-deficient): an exclusion diagnosis of "probable alpha thalassaemia" could be made in the remainder. We conclude that when microcytosis is present, routine further analysis of the original sequestrene sample by plasma ferritin assay and haemoglobinopathy screening could lead to a more efficient and cost-effective laboratory service for primary care and maternity services.

Epidemiology of haemoglobin disorders in Europe: an overview

OBJECTIVE

As a result of global population movements, haemoglobin disorders (thalassaemias and sickle cell disorders) are increasingly common in the formerly non-indigenous countries of Northern and Western Europe and in the indigenous countries of Southern Europe. This article presents an overview of the changing picture and a method for assessing service needs.

METHOD

Data on country of birth or ethnic origin of residents are adjusted to obtain the estimated proportions of residents and births in non-indigenous groups at risk for haemoglobin disorders in European countries. The results are combined with prevalence data in each country of origin to obtain country prevalence estimates. Service indicators (annual tests or other interventions required to ensure equitable delivery of treatment and prevention) are then derived by country.

RESULTS

Haemoglobin disorders now occur at comparable frequency throughout Northern, Western and Southern Europe. Annually, there are more affected conceptions in Northern and Western than in Southern Europe, and sickle cell disorders are more common than thalassaemias. There is growing need for health policy-makers to support motivated professionals working to develop optimal patient care, carrier diagnosis, genetic counselling and access to prenatal diagnosis throughout the Region.

CONCLUSION

There is a strong case for pan-European collaboration on haemoglobin disorders to share policies, standards and the instruments required to support them. These include methods for needs assessment, service standards, education and information strategies and materials, and methods for evaluating service delivery.

Quality of life in thalassemia

Morbidity and mortality related to thalassemia have been reduced significantly with modern medical treatment, and quality of life (QOL) should now be considered an important index of effective health care. An assessment of QOL differs from other forms of medical assessment in that it focuses on the individuals' own views of their well-being and assesses other aspects of life, giving a more holistic view of well-being. There is very little published work on evaluation of QOL in thalassemia. A suitable tool should be reproducible, sensitive to the major features of the condition that affect patients' lives, and applicable in the range of different cultural, age, and social settings. Such an instrument would be valuable in evaluating new forms of treatment and in comparing health outcomes between different clinics. Two instruments have been assessed, one derived from the WHOQOL-100 questionnaire, and one designed specifically for thalassemia, which assesses psychosocial and clinical burden, as they affect adult patients, parents, and children. Further studies are required to develop and assess such tools for use in thalassemia. Another approach is to seek patients' own views of their routine treatment and the extent to which medical treatment affects QOL. Results from patient questionnaires in the United Kingdom and Cyprus are consistent in finding problems with organization of transfusions, insufficient options with chelation therapy, and poor communication. Practical measures could be taken to address these issues.

Fourteen-Year Experience of Prenatal Diagnosis of Thalassemia in Iran

For 14 years, Iranian scientists have worked to develop a national thalassemia prevention program. Although historically abortion was considered unacceptable in Iran, intensive consultations led to the clerical approval of induced abortion in cases with beta-thalassemia major in 1997, and a nationwide prevention program with screening, counseling and prenatal diagnosis (PND) networks has been developed. This paper reports the experience from one of the two national PND reference laboratories. As one of the oldest reference laboratories, we performed a total of 906 PND in 360 couples at risk for thalassemia from 1990 to 2003. Direct and indirect mutation detection methods were applied for all cases. In total, 22 mutations were tested routinely, and an additional 30 rare mutations were identified. 208 fetuses were found to be normal, 215 fetuses had beta-thalassemia major, and 435 fetuses were carriers of the trait. In 40 cases, we only defined one allele. In 8 cases, we were unable to provide any diagnosis, corresponding to 0.9%. Our data support the functionality of the Iranian beta-thalassemia prevention program. The success of this system in Iran, a multiethnic and Islamic-based country, would mean that it might be applied as an adaptive system for neighboring and other Islamic countries.

Socio-economic inequalities as a predictor of health in South Africa--the Yenza cross-sectional study

OBJECTIVES

To describe the demographic, environmental and health characteristics of the rural Eastern Cape and to explore demographic and environmental predictors of health.

DESIGN

Cross-sectional study.

SETTING

Engcobo and Umtata in the Eastern Cape, South Africa.

SUBJECTS

12,049 people from 4608 households.

OUTCOME MEASURES

(i) Children: immunisation history and being breastfed; (ii) women aged 15-45 years: use of contraception; (iii) women aged 20-25 years: total numbers of dead children; and (iv) all adults: smoking status, body mass index and blood pressure.

RESULTS

2741 houses (59.5%) were structurally adequate, 1795 (39.0%) had access to clean water, and 1174 (25.6%) had access to gas or electric energy. Of children up to 5 years of age 1436 (44.2%) were fully immunised and 2472 (76.1%) were breastfed in their first year of life. Among women aged 15-45 years, 903 (37.8%) used contraceptives, and among women aged 20-25 years, 56 (11.8%) had lost at least 1 child. Self-report of chronic illness and disability was low. Current smokers include 264 men (12.7%) and 325 women (6.0%), and 315 men (15.2%) and 1439 women (26.7%) had a body mass index > 30. Adequate housing (odds ratio (OR) 1.31, 95% confidence interval (CI): 1.12-1.53) and access to refuse disposal (OR 1.65, 95% CI: 1.36-2.00) were predictive of complete immunisation in children. Children living in houses with access to clean water (OR 0.8, 95% CI: 0.64-0.99) and a fitted toilet (OR 0.56, 95% CI: 0.38-0.83) were less likely to be breastfed in the first year of their life. Women aged 15-45 years were likely to use contraception if they were well educated (OR 2.75, 95% CI: 1.76-4.28) and lived in houses with access to refuse disposal (OR 1.46, 95% CI: 1.20-1.78). Better education was associated with a reduced likelihood of loss of a child (OR 0.11, 95% CI: 0.02-0.51) and being a smoker (OR 0.52, 95% CI: 0.38-0.73). Obesity was associated with being female (OR 1.88, 95% CI: 1.62-2.18) and living in a house with electricity (OR 1.46, 95% CI: 1.26-1.68). High blood pressure was associated with living in a house with electricity (OR 1.36, 95% CI: 1.10-1.70) and with monthly household income exceeding R2 000 (OR 1.38, 95% CI: 1.07-1.78).

CONCLUSIONS

High socio-economic deprivation in the Eastern Cape is associated with health status comparable to that of poorer regions in sub-Saharan Africa. The educational level of the population, access to electricity, clean water and refuse disposal facilities are important predictors of child, maternal and adult health.

GPs' opinions of their role in prenatal genetic services: a cross-sectional survey

BACKGROUND

In the UK about 4.5% of the population carry cystic fibrosis, whilst in the inner city areas an even higher proportion carry one of the haemoglobin disorders such as thalassaemia. Couples who both carry the same recessive disorder have a 1 in 4 risk of an affected child in every pregnancy.

OBJECTIVES

To assess GPs' confidence in their ability to provide initial prenatal advice for couples carrying common autosomal recessive disorders (either the cystic fibrosis or thalassaemia gene), and their opinions of different approaches for referral to prenatal diagnostic services for such at-risk couples.

METHODS

A cross-sectional postal survey of all 644 GPs in 388 general practices in Nottinghamshire. Practices were randomly allocated to receive either the cystic fibrosis or the thalassaemia scenario survey. The survey questions predominantly used six-point Likert scales to assess confidence and opinions of prenatal services.

RESULTS

The questionnaire was returned by 62% (397) of GPs. Only 23% (91) were confident in providing prenatal advice to the at-risk carrier couples. GPs were more confident about advising cystic fibrosis carriers than thalassaemia carriers (P = 0.01). The least popular approach to prenatal service provision was direct referral to prenatal services after counselling with 52% (194) scoring this as useful, whilst 60.5% (233) of GPs scored referral to the obstetric services with the prenatal diagnosis organised by the obstetrician as useful.

CONCLUSIONS

GPs perceive that they lack the confidence to provide basic prenatal genetic advice to women at risk of the commonest recessive disorders, with particularly low confidence where the couple both carry thalassaemia. A significant knowledge gap was demonstrated by the poor awareness of the importance of rapid referral to prenatal diagnostic services.

Collecting genetic information in primary care: evaluating a new family history tool

BACKGROUND

The family history is a time-honoured method for identifying genetic predisposition. In specialist practice the standard approach is to draw up a family tree based on a genetic pedigree interview, but this is too time-consuming and focused on single gene disorders to be applicable in primary care.

OBJECTIVES

To assess the ability of a brief self-administered Family History Questionnaire (FHQ), given to patients when they register with a GP, to identify genetic risk.

METHODS

A comparative study. Informants completed an FHQ at registration, and later participated in a genetic pedigree interview. Two clinical geneticists independently scored results obtained with each instrument. Discrepancies were agreed by consensus. The genetic risks identified by the two instruments were compared.

RESULTS

326 new registrants completed the FHQ, and 121 also completed the genetic interview. 24% of FHQs and 36% of genetic interviews resulted in a score 'higher than population risk'. There was 77% agreement in the scores obtained with the two instruments, with a moderate kappa of 0.52. (95% CI 0.40-0.64). There was 90% agreement in the scores for a family history of premature coronary heart disease (Kappa 0.67; 95% CI 0.49 to 0.85). The instruments were equally effective in identifying ethnicity-related risk of common recessive disorders.

CONCLUSIONS

The FHQ identified most informants with genetic risks that are appropriately addressed in primary care-those with a family history of premature coronary heart disease, those warranting specialist referral, and those who might appropriately be offered carrier testing. However, it was less effective in identifying those with a possible Mendelian disorder for whom more information was required.

Informing carriers of beta-thalassemia: giving the good news

This study explored the value of informing beta-thalassaemia carriers of the advantages, as well as the disadvantages of carrier status. Twenty-eight carriers of beta-thalassaemia were interviewed immediately after counselling, and again 2 weeks later. Both interviews included administration of a psychological scale (previously used for cystic fibrosis). Immediately after the first interview the intervention group (n = 18) were informed of the protective effect of the beta-thalassaemia trait against malaria and coronary heart disease. The control group (n = 10) was given the same information after the second interview. The effect of giving the positive information was assessed by comparing participants' scores at the first and second interview. Knowledge of carrier status aroused several negative feelings, including shock, sadness, and anger, but little feeling of stigmatization. Two weeks later, negative feelings were unchanged in the control group, but they were reduced in all members of the intervention group. All members of the intervention group considered it important to inform carriers of the positive aspects as well as the risks associated with carrier status. Carriers of recessive disorders with a known heterozygote advantage should be informed of the advantage. This information has now been incorporated into the comprehensive information system for hemoglobin disorders available at http://www.chime.ucl.ac.uk/ApoGI/.

The history of community genetics: the contribution of the haemoglobin disorders

The emerging possibilities of applying new diagnostic technologies for genetic diagnosis and screening point to the need for a discipline of community genetics. Genetic population screening for haemoglobin disorders (thalassaemias and sickle cell disorders) has been practised on a large scale for over 20 years, and basic concepts and methods of community genetics have been developed within this framework, under the auspices of the WHO. Genetic population screening is a public health activity. It involves many disciplines, and planning depends on reliable and regularly updated information. Basic methods for describing genetic epidemiology in terms of service needs, and for regular service audit have been developed, and IT-based approaches for making simple, accurate and diagnosis-specific information accessible to the public and health professionals are being explored.

Timeline: Raising the profile of genetics in primary care

Primary care practitioners recognize that genetics is relevant to their daily practice, for example, for detecting and managing the risk of multifactorial disorders and genetic reproductive risks, and, in future, for targeted drug therapy. However, they lack confidence in their ability to apply genetic approaches. In fact, genetics is already ingrained in current practice, and the development of appropriate guidelines and web-based information resources will help practitioners to make personalized genetic risk assessment a part of holistic, patient-oriented primary health care.

Medical genetics in developing countries

Since Watson & Crick's 1953 description of the structure of DNA, significant progress has been achieved in the control of congenital disorders, most of which has benefited industrialized countries. Little advantage accrued to developing nations, most of which in the same time frame achieved a significant epidemiological transition, resulting in congenital disorders attaining public health significance. The burden of congenital disorders in these lower-resource countries is high and they need to develop medical genetic services. We present a new pragmatic approach for the care and prevention of congenital disorders in these countries, pioneered initially by the World Health Organization.

Iranian national thalassaemia screening programme

Iran's experience shows that genetic screening can be successful in lower resource countries and also provides some lessons for high resource nations

Recommendations for introducing genetics services in developing countries

Many concerned scientists believe that developments in the medical application of genomics will widen the gap between the developed and the developing world. We argue that most developing countries now urgently need to incorporate genetic approaches (including DNA diagnosis) into their health services, and that many are able to do so. DNA diagnosis is relatively inexpensive, helps to develop skills in molecular biology and provides a basis for developing national expertise in genomics.

Screening extended families for genetic hemoglobin disorders in Pakistan

BACKGROUND

We have investigated a strategy for identifying and counseling carriers of recessively inherited disorders in developing countries where consanguineous marriage is common. In such communities, gene variants are trapped within extended families, so that an affected child is a marker of a group at high genetic risk.

METHODS

Fifteen large Pakistani families, 10 with a history of a hemoglobin disorder and 5 without any such history (controls), were screened for beta-thalassemia and abnormal hemoglobins. All carriers and married couples consisting of two carriers received counseling, and eight families have been followed for two years.

RESULTS

In the control families, no carrier was found among 397 members tested. In the 10 families with an index case, 183 of 591 persons tested (31 percent) were carriers; carriers had a 25 percent risk of being in a marriage at risk for producing an affected child, and 17 of 214 married couples (8 percent) consisted of two carriers. No couple at risk was identified among 350 randomly selected pregnant women and their partners. All carriers reported that they have used the information provided in the testing and counseling process: carriers married to carriers with two or more healthy children have avoided further pregnancy, and most such couples with one or no healthy children have used prenatal diagnosis. Seven of eight new marriages and engagements are known not to be at risk.

CONCLUSIONS

Testing of extended families is a feasible way of deploying DNA-based genetic screening in communities in which consanguineous marriage is common.

Science and society: genetic counselling and customary consanguineous marriage

Consanguineous marriage is customary in many societies, but leads to an increased birth prevalence of infants with severe recessive disorders. It is therefore often proposed that consanguineous marriage should be discouraged on medical grounds. However, several expert groups have pointed out that this proposal is inconsistent with the ethical principles of genetic counselling, overlooks the social importance of consanguineous marriage and is ineffective. Instead, they suggest that the custom increases the possibilities for effective genetic counselling, and recommend a concerted effort to identify families at increased risk, and to provide them with risk information and carrier testing when feasible.

A national register for surveillance of inherited disorders: beta thalassaemia in the United Kingdom

OBJECTIVE

To demonstrate the value of a national register for surveillance of services for an inherited disorder.

METHODS

Data from the United Kingdom Thalassaemia Register and the United Kingdom Register of Prenatal Diagnosis for Haemoglobin Disorders were combined in a database; these registers include all fetuses known to have been diagnosed with beta thalassaemia major, beta thalassaemia intermedia, or haemoglobin E/beta thalassaemia in the United Kingdom. Data were extracted to show outcomes (selective abortion or live birth) of all fetuses and the status of those born with a disorder (alive, dead, successful bone marrow transplant, or lost to follow-up) by parents' region of residence and ethnicity.

FINDINGS

At the end of 1999 the register included 1074 patients, 807 of whom were alive and residing in the United Kingdom. A successful bone marrow transplant has been performed for 117 out of 581 (20%) patients born since 1975. Residents of Pakistani origin are now the main group at risk in the United Kingdom, replacing residents of Cypriot origin. This has led to a marked shift in the need for services from the south-east of England to the Midlands and the north of England. Despite the acceptability of prenatal diagnosis, the proportion of affected births remains 50% higher than would be expected, reflecting a widespread failure to deliver timely screening and counselling to carriers. Even though effective treatment is available the annual number of deaths is rising, indicating that better tolerated treatments are needed.

CONCLUSION

A national diagnosis register is a powerful instrument for monitoring the treatment and prevention of inherited disorders and for highlighting correctable shortcomings. In view of the increasing possibilities for genetic screening there is a strong case for central funding for such databases within modern health services.

Study of hemoglobinopathies in Oman through a national register

OBJECTIVES

A national register of symptomatic hemoglobinopathies has been developed in Oman to facilitate the development of the National Program for the control of genetic blood disorders.

METHODS

The information was initially collected retrospectively through hospital records and was refined prospectively with data collected through a survey of pediatricians. The percentages of heterozygotes in different population groups and geographical locations, birth prevalence, age distribution of cases and factors determining frequencies of Hemoglobinopathies in different regions of the country were studied from the register.

RESULTS

The register has identified 1757 cases of homozygous Sickle Cell Anemia and 243 cases of beta-thalassemia major in a population of 1.5 million in 1995. Register based national figures of heterozygote carriers approximate 10% for Sickle Cell Anemia and 4% for beta-thalassemia major.

CONCLUSION

Defining regional and tribal variations can assist efficient targeting of health resources. This approach provides a simple model for other countries or regions to follow providing there is a health care system that facilitates registration.

Accuracy of prenatal diagnosis for haemoglobin disorders in the UK: 25 years' experience

We have reviewed the accuracy of prenatal diagnosis for the thalassaemias and sickle cell disorders performed for UK residents since the service began in 1974. Prenatal diagnosis has been performed in 3254 pregnancies: 517 by fetal blood analysis, 681 by Southern blotting and 2056 by polymerase chain reaction (PCR) methods, the majority using the amplification refractory mutation system (ARMS). The number of homozygotes diagnosed was 808 (24.8%). Twenty-five diagnostic errors have been recorded, ten arising from non-laboratory errors (0.31%) and 15 due to technical problems associated with the diagnostic techniques. The latter group consisted of eight misdiagnoses by globin chain synthesis (1.55%), five by Southern blot analysis (0.73%) and two by PCR methods (0. 10%). The data show that the accuracy of prenatal diagnosis has improved with each development of diagnostic technique, and confirms that prenatal diagnosis of beta-thalassaemia and sickle cell disorders by ARMS-PCR is very accurate and reliable. The overall error rate for prenatal diagnosis by PCR methods in the UK is now 0. 41%.