Preconception carrier screening for multiple disorders: evaluation of a screening offer in a Dutch founder population

Prevalence of common autosomal recessive mutation carriers in women in the Southern Vietnam following the application of expanded carrier screening

The common autosomal recessive (AR) mutation carrier is still unknown in Vietnam. This study aims to identify the most common AR gene mutation carriers in women of reproductive age to build a Vietnamese-specific carrier screening panel for AR and X-linked disorders in the preconception and prenatal healthcare program. A cross-sectional study was conducted at University Medical Center-Branch 2 in Ho Chi Minh City from December 1st, 2020, to June 30th, 2023. 338 women have consented to take a 5 mL blood test to identify 540 recessive genes. The carrier screening panel was designed based on the American College of Medical Genetics and Genomics (ACMG)-recommended genes and suggestions from 104 clinical experts in Vietnam. Obstetricians and genetic experts counseled all positive testing results to discuss the possibility of recessive diseases in their offspring. The most common recessive disorders were defined at a prevalence of 1 in 60 or greater, and those were added to a Vietnamese-specific carrier screening panel. 338 non-pregnant and pregnant women underwent the expanded carrier screening (ECS). The carrier frequency was 63.6%, in which 215 women carried at least one AR gene mutation. GJB2 hearing impairment was identified as the most common chronic condition (1 in 5). The second most common AR disorder was beta-thalassemia (1 in 16), followed by cystic fibrosis (1 in 23), G6PD deficiency (1 in 28), Wilson's disease (1 in 31), Usher's syndrome (1 in 31), and glycogen storage disease (1 in 56). Seven common recessive genes were added in ethnic-based carrier screening. Women in the South of Vietnam have been carried for many recessive conditions at high frequency, such as hearing impairment, genetic anemia, and cystic fibrosis. It is necessary to implement a preconception and prenatal screening program by using seven widely popular AR genes in a Vietnamese-specific carrier screening panel to reduce the burden related to AR and X-linked disorders.

Multilevel barriers and facilitators to widespread use of preconception carrier screening in the United States

PURPOSE

Although preconception reproductive genetic carrier screening (RGCS) is preferred to screening during pregnancy, population-wide preconception screening is not routinely performed in the United States. We explored the multilevel barriers to the widespread adoption of preconception RGCS in the United States via key informant interviews.

METHODS

Semi-structured virtual video interviews were conducted with 29 informants with a breadth of professional expertise between May and October 2022. Data collection and qualitative analyses were guided by the Consolidated Framework for Implementation Research and socioecological model. Analysis focused on identifying barriers to delivering preconception RGCS at and across different levels of health care and exploring potential facilitators of preconception RGCS delivery.

RESULTS

Barriers to preconception RGCS were identified at the levels of test characteristics, patients and couples, clinicians and care teams, and the external health care and policy environments. Across the different levels of care delivery, 3 themes of barriers emerged: (1) fragmentation and inconsistencies hinder care delivery, (2) gaps in knowledge, misconceptions, and uncertainties about RGCS are pervasive, and (3) expanding preconception RGCS in the diverse US population presents unique implementation challenges. Potential solutions were detailed by informants.

CONCLUSION

Identifying individual and thematic barriers to preconception RGCS delivery may help to define strategies to alleviate obstacles.

Carrier screening programs for rare diseases in developed countries and the case of Turkey: A systematic review

Effective control of rare diseases requires health programs based on principles of protection and prevention. Carrier screening programs serve as preventive measures by identifying at-risk groups. This review examines the impact, implementation, advantages, and disadvantages of carrier screening, incorporating examples from ten countries: the United States, Canada, the United Kingdom, Israel, China, Australia, Italy, Germany, the Netherlands, and Turkey. Data on carrier screening and related policies were collected from July to November 2022 and presented in a tabular format using a coding system devised by the authors. Variability was observed in the diseases/disorders and populations screened, screening expenses, and government provision across the countries. The number of diseases/disorders examined, ranging from 3 to 47, was determined by committee guidelines, government resources, pilot studies, and national institute resources. Notably, carrier screening programs exhibited greater worldwide inconsistency compared to newborn screening programs. The comparative analysis of developed countries serves to guide emerging nations. To address inequalities at both local and global levels, there is a need to enhance the establishment, development, and implementation of carrier screening programs. Furthermore, cost analyses of screening should be conducted, and adequate funding should be allocated to countries. In conclusion, this review highlights the preventive potential of carrier screening for rare diseases and emphasizes the importance of improving carrier screening programs globally to achieve equitable healthcare outcomes.

Societal implications of expanded universal carrier screening: a scoping review

Carrier screening aims to identify couples at risk of conceiving children with a recessive condition. Until recently, carrier screening was primarily offered ancestry-based. Technological advances now facilitate expanded universal carrier screening (EUCS). This scoping review aimed to map EUCS's potential societal implications based on both theoretical studies and empirical evidence. To this aim, we performed a CoCites search to find relevant articles, including articles describing carrier screening for at-risk populations, based on five selected query articles. Forty articles were included. Three main potential societal implications were identified: (1) unwanted medicalization, (2) stigmatization and discrimination of carriers and people affected with the conditions screened and (3) challenges in achieving equitable access. Within these themes, potential positive implications are reduction of ethnic stigmatization in ancestry-based offers and increased equity. Potential negative implications are reinforcement of disability-based stigmatization, less possibility for developing expertise in healthcare and societal pressure to partake in screening. Empirical evidence on all these implications is however scarce. In conclusion, both positive and negative potential societal implications of implementing EUCS, primarily theoretical, were identified, even in at-risk groups where evidence is mostly lacking. Empirical research in EUCS pilots is needed to identify which societal implications are likely to occur and therefore should be overcome when implementing EUCS.

Cell therapy for the treatment of reproductive diseases and infertility: an overview from the mechanism to the clinic alongside diagnostic methods

Infertility is experienced by 8%-12% of adults in their reproductive period globally and has become a prevalent concern. Besides routine therapeutic methods, stem cells are rapidly being examined as viable alternative therapies in regenerative medicine and translational investigation. Remarkable progress has been made in understanding the biology and purpose of stem cells. The affected pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs) are further studied for their possible use in reproductive medicine, particularly for infertility induced by premature ovarian insufficiency and azoospermia. Accordingly, this study discusses current developments in the use of some kinds of MSCs such as adipose-derived stem cells, bone marrow stromal cells, umbilical cord MSCs, and menstrual blood MSCs. These methods have been used to manage ovarian and uterine disorders, and each technique presents a novel method for the therapy of infertility.

Genetic Counselling Needs for Reproductive Genetic Carrier Screening: A Scoping Review

Reproductive genetic carrier screening provides individuals and couples with information regarding their risk of having a child affected by an autosomal recessive or X-linked recessive genetic condition. This information allows them the opportunity to make reproductive decisions in line with their own beliefs and values. Traditionally, carrier screening has been accessed by family members of affected individuals. In recent years, improvements to accessibility and updates to recommendations suggest that all women planning or in early pregnancy should be offered reproductive genetic carrier screening. As uptake moves towards the population scale, how can the genetic counselling needs of such large-scale screening be met? A scoping review of the literature was performed to ascertain what the genetic counselling needs of reproductive genetic carrier screening are, and what future research is needed. Four broad themes were identified in the existing literature: (1) The offer-when and in what context to offer screening; (2) Information-the importance of and what to include in education, and pre- and post-test counselling; (3) Who and how-who the genetic counselling is performed by and how; (4) Personalization-how do we find the balance between standardized and individualized approaches? Based on the existing literature, we present a set of recommendations for consideration in implementing population-scale reproductive genetic carrier screening as well as suggested areas for future research.

Incorporating patient perspectives in the development of a core outcome set for reproductive genetic carrier screening: a sequential systematic review

There is currently no consensus on the key outcomes of reproductive genetic carrier screening (RGCS). This has led to a large amount of variability in approaches to research, limiting direct comparison and synthesis of findings. In a recently published systematic review of quantitative studies on RGCS, we found that few studies incorporated patient-reported outcomes. In response to this gap, we conducted a sequential systematic review of qualitative studies to identify outcomes exploring the patient experience of RGCS. In conjunction with the review of quantitative studies, these outcomes will be used to inform the development of a core outcome set. Text excerpts relevant to outcomes, including quotes and themes, were extracted verbatim and deductively coded as outcomes. We conducted a narrative synthesis to group outcomes within domains previously defined in our review of quantitative studies, and identify any new domains that were unique to qualitative studies. Seventy-eight outcomes were derived from qualitative studies and grouped into 19 outcome domains. Three new outcome domains were identified; 'goals of pre- and post-test genetic counselling', 'acceptability of further testing and alternative reproductive options', and 'perceived utility of RGCS'. The identification of outcome domains that were not identified in quantitative studies indicates that outcomes reflecting the patient perspective may be under-represented in the quantitative literature on this topic. Further work should focus on ensuring that outcomes reflect the real world needs and concerns of patients in order to maximise translation of research findings into clinical practice.

Systematic review of outcomes in studies of reproductive genetic carrier screening: Towards development of a core outcome set

PURPOSE

Current practice recommendations support the widespread implementation of reproductive genetic carrier screening (RGCS). These consensus-based recommendations highlight a research gap, with findings from current studies being insufficient to meet the standard required for more rigorous evidence-based recommendations. This systematic review assessed methodological aspects of studies on RGCS to inform the need for a core outcome set.

METHODS

We conducted a systematic search to identify peer-reviewed published studies offering population-based RGCS. Study designs, outcomes, and measurement methods were extracted. A narrative synthesis was conducting using an existing outcome taxonomy and criteria used in the evaluation of genetic screening programs as frameworks.

RESULTS

Sixty-five publications were included. We extracted 120 outcomes representing 24 outcome domains. Heterogeneity in outcome selection, measurement methods and time points of assessment was extensive. Quality appraisal raised concerns for bias. We found that reported outcomes had limited applicability to criteria used to evaluate genetic screening programs.

CONCLUSION

Despite a large body of literature, diverse approaches to research have limited the conclusions that can be cumulatively drawn from this body of evidence. Consensus regarding meaningful outcomes for evaluation of RGCS would be a valuable first step in working towards evidence-based practice recommendations, supporting the development of a core outcome set.

Couples' experiences with expanded carrier screening: evaluation of a university hospital screening offer

Preconception carrier screening offers couples the possibility to receive information about the risk of having a child with a recessive disorder. Since 2016, an expanded carrier screening (ECS) test for 50 severe autosomal recessive disorders has been available at Amsterdam Medical Center, a Dutch university hospital. This mixed-methods study evaluated the experiences of couples that participated in the carrier screening offer, including high-risk participants, as well as participants with a general population risk. All participants received genetic counselling, and pre- (n = 132) and post-test (n = 86) questionnaires and semi-structured interviews (n = 16) were administered. The most important reason to have ECS was to spare a future child a life with a severe disorder (47%). The majority of survey respondents made an informed decision (86%), as assessed by the Multidimensional Measure of Informed Choice. Among the 86 respondents, 27 individual carriers and no new carrier couples were identified. Turn-around time of the test results was considered too long and costs were perceived as too high. Overall, mean levels of anxiety were not clinically elevated. High-risk respondents (n = 89) and pregnant respondents (n = 13) experienced higher levels of anxiety before testing, which decreased after receiving the test result. Although not clinically significant, distress was on average higher for carriers compared to non-carriers (p < 0.0001). All respondents would opt for the test again, and 80.2% would recommend it to others. The results suggest that ECS should ideally be offered before pregnancy, to minimise anxiety. This study could inform current and future implementation initiatives of preconception ECS.

Molecular classification of blood and bleeding disorder genes

The advances and development of sequencing techniques and data analysis resulted in a pool of informative genetic data, that can be analyzed for informing decision making in designing national screening, prevention programs, and molecular diagnostic tests. The accumulation of molecular data from different populations widen the scope of utilization of this information. Bleeding disorders are a heterogeneous group of clinically overlapping disorders. We analyzed the targeted sequencing data from ~1285 Saudi individuals in 17 blood and bleeding disorders genes, to determine the frequency of mutations and variants. We used a replication set of ~5000 local exomes to validate pathogenicity and determine allele frequencies. We identified a total of 821 variants, of these 98 were listed in HGMD as disease related variants and 140 were novel variants. The majority of variants were present in VWF, followed by F5, F8, and G6PD genes, while FGG, FGB, and HBA1 had the lowest number of variants. Our analysis generated a priority list of genes, mutations and novel variants. This data will have an impact on informing decisions for screening and prevention programs and in management of vulnerable patients admitted to emergency, surgery, or interventions with bleeding side effects.

Couple-based expanded carrier screening provided by general practitioners to couples in the Dutch general population: psychological outcomes and reproductive intentions

Purpose

The aim of expanded preconception carrier screening (ECS) is to inform any couple wishing to conceive about their chances of having children with severe autosomal or X-linked recessive conditions. Responsible implementation of ECS as reproductive genetic screening in routine care requires assessment of benefits and harms. We examined the psychological outcomes of couple-based ECS for 50 autosomal recessive (AR) conditions provided by general practitioners (GPs) to couples from the Dutch general population.

Methods

Dutch GPs invited 4,295 women aged 18–40. We examined anxiety (State-Trait Anxiety Inventory, STAI-6), worry, decisional conflict (DCS) over time in participants declining GP counseling or attending GP counseling with/without testing.

Results

One hundred ninety couples participated; 130 attended counseling, of whom 117 proceeded with testing. No carrier couples were identified. Before counseling, worry (median 6.0) and anxiety (mean 30–34) were low and lower than the population reference (36.4), although some individuals reported increased anxiety or worry. At follow-up, test acceptors reported less anxiety than test decliners (mean 29 vs. 35); differences in anxiety after testing compared to before counseling were not meaningful. Most participants (90%) were satisfied with their decision (not) to undergo testing.

Conclusion

Some individuals reported temporarily clinically relevant distress. Overall, the psychological outcomes are acceptable and no barrier to population-wide implementation.

Expanded carrier screening in Flanders (Belgium): an online survey on the perspectives of nonpregnant reproductive-aged women

Aim: Despite a considerable interest in expanded carrier screening (ECS) in the general population, actual uptake of ECS remains low. More insights are needed to better understand the perspectives of reproductive-aged individuals. Materials & methods: Nonpregnant women of reproductive age recruited through public pharmacies throughout Flanders (Belgium) were invited to participate in an online survey. Results: Most participants (63.6%) indicated they would consider ECS for themselves in the future. About one in two participants showed a positive attitude toward ECS. Conclusion: This study reports valuable insights in the perspectives of nonpregnant reproductive-aged women in Flanders (Belgium) regarding ECS that can be used in the ongoing debate on the responsible implementation of ECS.

Reproductive options for families at risk of Osteogenesis Imperfecta: a review

Background

Osteogenesis Imperfecta (OI) is a rare genetic disorder involving bone fragility. OI patients typically suffer from numerous fractures, skeletal deformities, shortness of stature and hearing loss. The disorder is characterised by genetic and clinical heterogeneity. Pathogenic variants in more than 20 different genes can lead to OI, and phenotypes can range from mild to lethal forms. As a genetic disorder which undoubtedly affects quality of life, OI significantly alters the reproductive confidence of families at risk. The current review describes a selection of the latest reproductive approaches which may be suitable for prospective parents faced with a risk of OI. The aim of the review is to alleviate suffering in relation to family planning around OI, by enabling prospective parents to make informed and independent decisions.

Main body

The current review provides a comprehensive overview of possible reproductive options for people with OI and for unaffected carriers of OI pathogenic genetic variants. The review considers reproductive options across all phases of family planning, including pre-pregnancy, fertilisation, pregnancy, and post-pregnancy. Special attention is given to the more modern techniques of assisted reproduction, such as preconception carrier screening, preimplantation genetic testing for monogenic diseases and non-invasive prenatal testing. The review outlines the methodologies of the different reproductive approaches available to OI families and highlights their advantages and disadvantages. These are presented as a decision tree, which takes into account the autosomal dominant and autosomal recessive nature of the OI variants, and the OI-related risks of people without OI.

The complex process of decision-making around OI reproductive options is also discussed from an ethical perspective.

Conclusion

The rapid development of molecular techniques has led to the availability of a wide variety of reproductive options for prospective parents faced with a risk of OI. However, such options may raise ethical concerns in terms of methodologies, choice management and good clinical practice in reproductive care, which are yet to be fully addressed.

Expanded universal carrier screening and its implementation within a publicly funded healthcare service

Carrier screening, a well-established clinical initiative, has been slow to take advantage of the new possibilities offered by high-throughput next generation sequencing technologies. There is evidence of significant benefit in expanding carrier screening to include multiple autosomal recessive conditions and offering a ‘universal’ carrier screen that could be used for a pan-ethnic population. However, the challenges of implementing such a programme and the difficulties of demonstrating efficacy worthy of public health investment are significant barriers. In order for such a programme to be successful, it would need to be applicable and acceptable to the population, which may be ethnically and culturally diverse. There are significant practical and ethical implications associated with determining which variants, genes and conditions to include whilst maintaining adequate sensitivity and accuracy. Although preconception screening would maximise the potential benefits from universal carrier screening, the resource implications of different modes of delivery need to be carefully evaluated and balanced against maximising reproductive autonomy and ensuring equity of access. Currently, although a number of existing initiatives are increasing access to carrier screening, there is insufficient evidence to inform the development of a publicly funded, expanded, universal carrier screening programme that would justify investment over other healthcare interventions.

How does carrier status for recessive disorders influence reproductive decisions? A systematic review of the literature

Introduction: Carrier screening for recessive disorders is undertaken by prospective parents to inform their reproductive decisions. With the growing availability of affordable and comprehensive expanded carrier screening (ECS), it is expected that carrier screening will become a standard practice in the future. However, the impact of positive carrier screening results on the reproductive decisions of at-risk couples (ARCs) remains underexplored.Areas covered: We performed a systematic literature review to identify peer-reviewed publications describing the reproductive decisions of ARCs. Our search identified 19 relevant publications spanning the period 1994-2018. By synthesizing available evidence, we found that most ARCs chose to prevent the birth of an affected child and the decision to utilize preventive reproductive options was strongly influenced by the clinical nature of a disorder. However, there was also some heterogeneity in reproductive decisions within the same recessive disorders, suggesting that choices of ARCs can be influenced by factors other than the clinical nature of a disorder.Expert opinion: ECS is becoming increasingly common, which will result in the routine identification of many ARCs. Reproductive decision-making by ARCs is a complex and emotionally challenging process, highlighting the critical role of genetic counseling in the care for these potentially vulnerable patients.

The evolving role of genetic tests in reproductive medicine

Infertility is considered a major public health issue, and approximately 1 out of 6 people worldwide suffer from infertility during their reproductive lifespans. Thanks to technological advances, genetic tests are becoming increasingly relevant in reproductive medicine. More genetic tests are required to identify the cause of male and/or female infertility, identify carriers of inherited diseases and plan antenatal testing. Furthermore, genetic tests provide direction toward the most appropriate assisted reproductive techniques. Nevertheless, the use of molecular analysis in this field is still fragmented and cumbersome. The aim of this review is to highlight the conditions in which a genetic evaluation (counselling and testing) plays a role in improving the reproductive outcomes of infertile couples. We conducted a review of the literature, and starting from the observation of specific signs and symptoms, we describe the available molecular tests. To conceive a child, both partners' reproductive systems need to function in a precisely choreographed manner. Hence to treat infertility, it is key to assess both partners. Our results highlight the increasing importance of molecular testing in reproductive medicine.

Attitudes of the general population towards preconception expanded carrier screening for autosomal recessive disorders including inborn errors of metabolism

BACKGROUND

A substantial number of severely debilitating and often ultimately fatal inborn errors of metabolism (IEMs) still lack an effective disease-modifying treatment. Informing couples before a pregnancy about an increased risk of having a child with an inherited disorder is now feasible by preconception expanded carrier screening (ECS). While knowledge about carrier status enhances reproductive autonomy, it may also result in ethical dilemmas. The purpose of this study was to assess the attitudes of the general Dutch population towards preconception ECS and to investigate which factors influence these attitudes.

METHODS

Data collection was carried out in collaboration with a market research agency. In total, 1188 Dutch individuals of reproductive age (18-45 years) were invited by email to complete an online ECS questionnaire in 2016. Prior to the start of the questionnaire, a written explanation of the concepts of autosomal recessive (AR) inheritance, carrier status and ECS was presented.

RESULTS

The questionnaire was completed by 781 individuals (65.7%), of whom 31% indicated they would take an ECS test themselves. In addition, 55% agreed that ECS should be offered to all prospective parents. The most frequently selected argument in favor of ECS (47.2%) was that participants want to spare a child from a life with a severe hereditary disorder. The reason most often mentioned not to participate in ECS (48%) was that participants reported not having a hereditary disorder in the family. The majority preferred receiving individual test results above a couple-based disclosure method in which participants receive the carrier status results only when they are a carrier couple of the same disorder. Participants with religious beliefs were less likely to participate in ECS, whereas participants who were considering a (future) pregnancy were more likely to participate.

CONCLUSION

Our study demonstrates an overall positive attitude among participants of reproductive age in the general Dutch population towards preconception ECS. A striking misconception is that many of the participants believe that ECS is of interest only for those with a positive family history of one of the hereditary disorders. This finding emphasizes the importance of providing understandable, balanced information and education to the general public regarding the concepts of inheritance when presenting the option of carrier screening. Our results provide valuable insights that can be used in the debate about the responsible implementation of preconception ECS for AR disorders, including IEMs.