Next-Generation Sequencing in Newborn Screening: A Review of Current State

Newborn screening was first introduced at the beginning of the 1960s with the successful implementation of the first phenylketonuria screening programs. Early expansion of the included disorders was slow because each additional disorder screened required a separate test. Subsequently, the technological advancements of biochemical methodology enabled the scaling-up of newborn screening, most notably with the implementation of tandem mass spectrometry. In recent years, we have witnessed a remarkable progression of high-throughput sequencing technologies, which has resulted in a continuous decrease of both cost and time required for genetic analysis. This has enabled more widespread use of the massive multiparallel sequencing. Genomic sequencing is now frequently used in clinical applications, and its implementation in newborn screening has been intensively advocated. The expansion of newborn screening has raised many clinical, ethical, legal, psychological, sociological, and technological concerns over time. This review provides an overview of the current state of next-generation sequencing regarding newborn screening including current recommendations and potential challenges for the use of such technologies in newborn screening.

Families' Experiences with Newborn Screening: A Critical Source of Evidence

Debates about expanding newborn screening with whole genome sequencing are fueled by data about public perception, public opinion, and the positions taken by public advocates and advocacy groups. One form of evidence that merits attention as we consider possible uses of whole-genome sequencing during the newborn period is parents' (and children's) diverse experiences with existing expanded screening protocols. What do we know about this experience base? And what implications might these data have for decisions about how we use whole genome sequencing and how we assess its impact in the future? Although the broader literature on genetic susceptibility testing suggests that testing usually does not have adverse effects on children's psychosocial well-being, certain newborn screening results have been demonstrated to cause distress, alter behavior, and even to influence the formation of new parental and family identities.

Psychosine, a marker of Krabbe phenotype and treatment effect

Newborn screening (NBS) for Krabbe disease, a rare neurodegenerative disorder caused by deficient galactocerebrosidase (GALC) enzyme activity, has recently been implemented in a number of US states. However, the spectrum of phenotypic manifestations associated with deficient GALC activity complicates the management of screen-positive newborns and underscores the need to identify clinically relevant biomarkers. Earlier studies with a small number of patients identified psychosine, a substrate of the GALC enzyme, as a potential biomarker for Krabbe disease. In this study, we provide, for the first time, longitudinal data on dried blood spot (DBS) psychosine concentrations in different Krabbe disease phenotypes for both untreated patients and those treated with hematopoietic stem cell transplantation (HSCT). Our cohort included patients previously identified by NBS to be at high risk to develop Krabbe disease. Substantially elevated DBS psychosine concentration during the newborn period was found to be a highly specific marker for infantile Krabbe disease. This finding supports the use of DBS psychosine concentration as a second-tier NBS test to aid in the identification of patients who require urgent evaluation for HSCT. In addition, longitudinal assessments showed that both natural disease progression and treatment with HSCT were associated with decreases in DBS psychosine concentrations. Based on these findings we provide recommendations for the interpretation of psychosine concentrations in DBS specimens collected during the first year of life. Future studies should aim to better delineate the relationship between DBS psychosine concentration and disease onset in patients with later-onset forms of Krabbe disease.

Policy Making in Newborn Screening Needs a Structured and Transparent Approach

PURPOSE

Newborn bloodspot screening (NBS) programs have expanded significantly in the past years and are expected to expand further with the emergence of genetic technologies. Historically, NBS expansion has often occurred following ad hoc consideration of conditions, instead of a structured and transparent approach. In this review, we explore issues pertinent to NBS policy making, through the lens of the policy cycle: (a) agenda setting, (b) policy advice, (c) policy decision, (d) implementation, and (e) evaluation.

METHODS

A literature search was conducted to gather information on the elements specific to NBS and its policy making process.

RESULTS

The review highlighted two approaches to nominate a condition: a structured approach through horizon scanning; and an ad hoc process. For assessment of a condition, there was unanimous support for a robust process based on criteria. While the need to assess harms and benefits was a repeated theme in the articles, there is no agreed-upon threshold for benefit in decision-making. Furthermore, the literature was consistent in its recommendation for an overarching, independent, multidisciplinary group providing recommendations to government. An implementation plan focusing on the different levels on which NBS operates and the information needed on each level is essential for successful implementation. Continuously monitoring, and improving a program is vital, particularly following the implementation of screening for a new condition. An advisory committee could advise on implementation, development, review, modification, and cessation of (parts of) NBS.

CONCLUSION

The results highlight that there are a wave of issues facing NBS programs that policy makers must take into account when developing policy processes. What conditions to screen, and the technologies used in NBS, are both up for debate.

Review of Current International Decision-Making Processes for Newborn Screening: Lessons for Australia

Newborn bloodspot screening has been operating successfully in Australia for almost 50 years. Recently, the development of new technologies and treatments has led to calls for the addition of new conditions to the screening programs. Internationally, it is recognized by governments that national policies for newborn screening should support transparent and evidence-based decision making, and promote consistency between states within a country. Australia is lagging behind the international community, and currently has no national policies or decision-making processes, agreed by government, to support its newborn screening programs. In contrast, New Zealand (NZ), the United Kingdom (UK), and the United States of America (US) have robust and transparent processes to assess conditions for screening, which have been developed by, and have pathways to, government. This review provides detail on the current policy environment for newborn screening in Australia, highlighting that there are a number of risks to the programs resulting from the lack of a decision-making process. It also describes the processes used to assess conditions for newborn screening in the US, UK, and NZ. These examples highlight the benefits of developing a national decision-making process, including ensuring that screening is evidence based and effective. These examples also provide models that might be considered for Australia, as well as other countries currently seeking to introduce or expand newborn bloodspot screening.

Ethical and policy issues in newborn screening of children for neurologic and developmental disorders

Genetic testing for neurologic and developmental disorders spans the spectrum from universal newborn screening for conditions like phenylketonuria to diagnostic testing for suspected genetic conditions, to predictive genetic testing for childhood-onset conditions. Given that virtually all children in the United States undergo genetic screening in the newborn period, this article focuses on 3 actual case studies of neurologic and developmental disorders that have been included or proposed for inclusion in newborn screening programs: Duchenne muscular dystrophy (a neuromuscular disorder), Krabbe disease (a neurodegenerative disorder), and fragile X syndrome (a neurodevelopmental disorder).

Fifty years of newborn screening

Newborn screening has evolved fast following recent advances in diagnosis and treatment of disease, particularly the development of multiplex testing and applications of molecular testing. Formal evidence of benefit from newborn screening has been largely lacking, due to the rarity of individual disorders. There are wide international differences in the choice of disorders screened, and ethical issues in both screening and not screening are apparent. More evidence is needed about benefit and harm of screening for specific disorders and renewed discussion about the basic aims of newborn screening must be undertaken.

Benefits and burdens of newborn screening: public understanding and decision-making

In this article we review the literature regarding the public understanding of the potential benefits and burdens of expanded newborn bloodspot screening. We draw attention to broadened notions of benefit that go beyond early identification of asymptomatic individuals and interventions to reduce morbidity or mortality, and include benefits gained by families through knowledge that may facilitate life choices, as well as gains generated by avoiding diagnostic delays. We also reflect on burdens such as increasing false-positive results and parental anxiety, together with risks of overdiagnosis when the natural history of a condition is poorly understood. We conclude that expanded notions of benefit and burden bring with them implications for parental consent and confidentiality and the secondary use of bloodspots.

[Quaternary prevention: containment as an ethical necessity]

The growing capacity of medicine to generate more iatrogenic events than ever, and the risk of unsustainability of health systems have led to new prevention concept: quaternary prevention aimed at restraining medicalization. Quaternary prevention is essential in the phenomenon called disease mongering, which could be translated as commercialization of disease. Encouraging this sort of prevention and halting the consequences of disease mongering requires the development of all the institutional potential for prevention, as well as all the personal willingness for restraint; it involves separating us from the unnecessary auspices of industry, being critical of our work, not being maleficent, respecting the principle of justice as managers of the limited public resources and making ourselves feel responsible for the social cost resulting from medical decisions. From this point of view, this work analyses neonatal screening, developments in the area of neonatology and primary health care.