Newborn screening for lysosomal storage diseases: an ethical and policy analysis

Screening for lysosomal diseases in a selected pediatric population: the case of Gaucher disease and acid sphingomyelinase deficiency

BACKGROUND

GD and ASMD are lysosomal storage disorders that enter into differential diagnosis due to the possible overlap in their clinical manifestations. The availability of safe and effective enzymatic therapies has recently led many investigators to develop and validate new screening tools, such as algorithms, for the diagnosis of LSDs where the lack of disease awareness or failure to implement newborn screening results in a delayed diagnosis.

RESULTS

the proposed algorithm allows for the clinical and biochemical differentiation between GD and ASMD. It is based on enzyme activity assessed on dried blood spots by multiplexed tandem mass spectrometry (MS/MS) coupled to specific biomarkers as second-tier analysis.

CONCLUSIONS

we believe that this method will provide a simple, convenient and sensitive tool for the screening of a selected population that can be used by pediatricians and other specialists (such as pediatric hematologists and pediatric hepatologists) often engaged in diagnosing these disorders.

A Qualitative Study: Mothers' Experiences of Their Child's Late-Onset Pompe Disease Diagnosis Following Newborn Screening

Pompe disease was added to the United States recommended uniform screening panel in 2015 to avoid diagnostic delay and implement prompt treatment, specifically for those with infantile-onset Pompe disease (IOPD). However, most newborns with abnormal newborn screening (NBS) for Pompe disease have late-onset Pompe disease (LOPD). An early diagnosis of LOPD raises the question of when symptoms will arise which is challenging for parents, patients, and providers managing an LOPD diagnosis. This study aimed to characterize mothers' experiences of their child's LOPD diagnosis and medical monitoring. A qualitative descriptive approach was chosen to gain an in-depth understanding of parental experiences. Eight mothers were interviewed about their experiences with positive NBS and diagnosis, experiences with living with the diagnosis, and experiences with medical monitoring. Interview transcripts were analyzed through conventional content analysis. Negative emotions like fear were more frequent with communication of NBS results. Participants expressed uncertainty surrounding age of symptom onset and the future. The medical monitoring experience increased worry but participants expressed that being vigilant with management reassured them. Parental emotions shifted to thankfulness and reassurance with time and education. These findings can provide guidance to providers about the psychosocial implications of receiving positive NBS results and an LOPD diagnosis.

Newborn screening for Fabry disease in Oregon: Approaching the iceberg of A143T and variants of uncertain significance

Fabry disease newborn screening (NBS) has been ongoing in Oregon for over 41 months by first-tier enzyme quantitation and second-tier DNA testing. During that period the majority of abnormal referrals received (34/60) were for the presence of the controversial c.427G > A (p.Ala143Thr) aka A143T and the majority of non-A143T referrals were for other variants of uncertain significance (17/60) resulting in at least 32 infants with an inconclusive case outcome even after clinical evaluation and/or diagnostic testing. To date there has been no significant family history or onset of symptoms in individuals with an inconclusive outcome. Based on our experience, we have developed a framework for approaching A143T and other variants of uncertain clinical significance in an attempt to balance sensitivity with the unnecessary medicalization of healthy infants.

Health care practitioners' experience-based opinions on providing care after a positive newborn screen for Pompe disease

The addition of Pompe disease (PD) and other conditions with later-onset forms to newborn screening (NBS) in the United States (US) has been controversial. NBS technology cannot discern infantile-onset PD (IOPD) from later-onset PD (LOPD) without clinical follow-up. This study explores genetic health care practitioners' (HCPs) experiences and challenges providing NBS patient care throughout the US and their resultant opinions on NBS for PD. An online survey was distributed to genetic counselors, geneticists, NBS follow-up care coordinators, and nurse practitioners caring for patients with positive NBS results for PD. Analysis of 78 surveys revealed the majority of participating HCPs support inclusion of PD on NBS. Almost all HCPs (93.3%) feel their state has sufficient resources to provide follow-up medical care for IOPD; however, only three-fourths (74.6%) believed this for LOPD. Common barriers included time lag between NBS and confirmatory results, insurance difficulties for laboratory testing, and family difficulties in seeking medical care. HCPs more frequently encountered barriers providing care for LOPD than IOPD (53.9% LOPD identified ≥3 barriers, 31.1% IOPD). HCPs also believe creation of a population of presymptomatic individuals with LOPD creates a psychological burden on the family (87.3% agree/strongly agree), unnecessary medicalization of the child (63.5% agree/strongly agree), and parental hypervigilance (68.3% agree/strongly agree). Opinions were markedly divided on the use of reproductive benefit as a justification for NBS. Participants believe additional education for pediatricians and other specialists would be beneficial in providing care for patients with both IOPD and LOPD, in addition to the creation of evidence-based official guidelines for care and supportive resources for families with LOPD.

Opinions of adults affected with later-onset lysosomal storage diseases regarding newborn screening: A qualitative study

Lysosomal storage diseases (LSDs) are a heterogeneous group of conditions causing substrate accumulation leading to progressive organ damage. Newborn screening (NBS) for several LSDs has become available in recent years due to advances in technology and treatment availability. While early initiation of treatment is lifesaving for those with infantile presentations, controversy continues regarding diagnosis of milder, later-onset diseases in infancy, including creation of pre-symptomatic populations of 'patients-in-waiting', the potential for medicalization, stigmatization, and/or discrimination. In-depth interviews were conducted with 36 adults [11 with Fabry disease (FD), 8 with Gaucher disease (GD), and 17 with late-onset Pompe disease (LOPD)], to determine their perspectives on NBS for their respective conditions. Thirty-four of 36 participants were in favor of NBS; both participants not in favor had GD1. Emergent themes influencing participants favorably toward NBS included earlier age of onset, a long diagnostic odyssey, less efficacious treatment, and the desire to have made different life decisions (e.g., relationships, career, or lifestyle) with the knowledge of their diagnosis. Concerns about insurance discrimination and psychological or physical burdens were associated with less favorable opinions of NBS. The ability for parents to make future reproductive decisions based their child's NBS result was considered favorably by some participants and unfavorably by others. Participants' specific condition (GD1, FD, or LOPD) contributed to these experiences differently. Participants with LOPD and FD favored NBS to initiate earlier treatment and prevent irreversible organ damage, whereas fewer patients with GD1 mentioned this benefit. Participants with LOPD had the longest diagnostic odyssey, while those with FD were more likely to report feeling misunderstood and experiencing accusations of malingering, both contributing to favorable views of NBS. Results expand prior quantitative findings by illuminating how participants' lived experiences can shape opinions about NBS. By understanding how currently affected individuals perceive the lifelong impact of a NBS result, genetic counselors can provide better anticipatory guidance to the parents of individuals diagnosed with a later-onset LSD by NBS.

Spinal Muscular Atrophy: Past, Present, and Future

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease caused by deletions or mutations in the survival motor neuron (SMN1) gene. SMA is characterized by loss of lower motor neurons (anterior horn cells) in the spinal cord and brainstem nuclei, leading to progressive symmetrical muscle weakness and atrophy. It affects approximately 1 in 6,000 to 1 in 10,000 individuals and is the most common inherited cause of childhood mortality, but this may soon change given recent developments. In December 2016, nusinersen, an antisense oligonucleotide drug, was approved by the United States Food and Drug Administration for the treatment of SMA, and in July 2018, SMA was added to the recommended uniform screening panel, a list of conditions that all states are encouraged to include in their newborn screening (NBS) panels. In this review, we begin with a brief clinical history of the diagnosis of SMA, discuss the current SMA clinical classification system, describe the current treatment, and discuss evolving treatment guidelines. We then discuss the path to include SMA in NBS programs as well as the controversies it engenders because the variability in age at symptom onset means early identification of asymptomatic patients who will not require therapy for years or decades. We also consider alternate population screening opportunities. Next, we consider experimental treatments. We conclude by supporting NBS for SMA with the caveat that a long-term follow-up registry is ethically essential to ensure that the benefits outweigh the harms for all screened infants, including those with milder and/or later-onset forms of SMA.

Ethical issues with testing and treatment for Krabbe disease

Early-infantile Krabbe disease (EIKD) is an autosomal recessive, progressive, neurodegenerative disorder that usually leads to death in infancy. A study published in 2005 indicated that hematopoietic stem-cell transplantation (HSCT) was effective in the treatment for EIKD when used before the onset of symptoms. This finding suggested that newborn screening for EIKD, which would allow earlier diagnosis, might lead to earlier treatment and better outcomes. In 2006, New York was the first state to implement newborn screening for Krabbe disease; however, the results were not as good as proponents had hoped. In this paper, we present the history of efforts to diagnose and treat EIKD. Based on our findings, we question the efficacy of newborn screening for Krabbe disease. We present two arguments. First, testing itself is too imprecise. Even with the most rigorous testing standards, such as those used in New York, many of the children who are identified as being 'at risk' for EIKD remain asymptomatic. It is unclear if they will remain asymptomatic forever and, thus, whether the tests should be considered 'false positives', or whether they will eventually develop the disease. Second, we question the efficacy of early HSCT. We recommend placing a moratorium on mandatory newborn screening for EIKD. WHAT THIS PAPER ADDS: Current tests to identify which children are likely to develop Krabbe diseased are inadequate. Many children identified as being 'at risk' for early infantile Krabbe disease remain asymptomatic. Psychosine appears to be more specific than low galactosylceramidase levels for diagnosing early infantile Krabbe disease.

Newborn screening for Pompe disease: impact on families

Pompe disease (PD) is an autosomal recessive lysosomal storage disorder causing progressive glycogen accumulation in muscles, with variability in age of onset and severity. For infantile-onset PD (IOPD), initiation of early treatment can be life-saving; however, current newborn screening (NBS) technology cannot distinguish IOPD from late-onset PD (LOPD) without clinical workup. Therefore, families of LOPD infants diagnosed by NBS may now spend years or even decades aware of their illness before symptoms appear, creating a pre-symptomatic awareness phase with which the medical community has little experience. The present study examines the effects of receiving a positive NBS result for PD on families. In-depth qualitative interviews were conducted with mothers of nine children (three IOPD and six LOPD) diagnosed via NBS, exploring their experiences, understanding of PD, how they are coping, and what impact diagnosis is having on family life. Interviews were coded using MaxQDA v.12 and analyzed for thematic trends. While overall opinion of NBS was favorable, it is clear many of the concerns anticipated by HCPs, patients, and families regarding NBS for late-onset LSDs are being realized to varying degrees; LOPD families are becoming patients-in-waiting. Increased fear/anxiety and living with uncertainty (regarding diagnosis, their children's future, and when to start treatment) were predominant themes, with all families voicing considerable emotional reactions and varied social and healthcare support concerns. Coping strategies and psychosocial challenges are interpreted using Rolland & Williams' Family Systems Genetic Illness model. Recommendations for improvement in delivery of service, as well as families' advice for future parents and HCPs, are discussed.

Including ELSI research questions in newborn screening pilot studies

BACKGROUND

The evidence review processes for adding new conditions to state newborn screening (NBS) panels rely on data from pilot studies aimed at assessing the potential benefits and harms of screening. However, the consideration of ethical, legal, and social implications (ELSI) of screening within this research has been limited. This paper outlines important ELSI issues related to newborn screening policy and practices as a resource to help researchers integrate ELSI into NBS pilot studies.

APPROACH

Members of the Bioethics and Legal Workgroup for the Newborn Screening Translational Research Network facilitated a series of professional and public discussions aimed at engaging NBS stakeholders to identify important existing and emerging ELSI challenges accompanying NBS.

RESULTS

Through these engagement activities, we identified a set of key ELSI questions related to (1) the types of results parents may receive through newborn screening and (2) the initiation and implementation of NBS for a condition within the NBS system.

CONCLUSION

Integrating ELSI questions into pilot studies will help NBS programs to better understand the potential impact of screening for a new condition on newborns and families, and make crucial policy decisions aimed at maximized benefits and mitigating the potential negative medical or social implications of screening.

Newborn Screening for Lysosomal Storage Disorders in Illinois: The Initial 15-Month Experience

OBJECTIVES

To assess the outcomes of newborn screening for 5 lysosomal storage disorders (LSDs) in the first cohort of infants tested in the state of Illinois.

STUDY DESIGN

Tandem mass spectrometry was used to assay for the 5 LSD-associated enzymes in dried blood spot specimens obtained from 219 973 newborn samples sent to the Newborn Screening Laboratory of the Illinois Department of Public Health in Chicago.

RESULTS

The total number of cases with a positive diagnosis and the incidence for each disorder were as follows: Fabry disease, n = 26 (1 in 8454, including the p.A143T variant); Pompe disease, n = 10 (1 in 21 979); Gaucher disease, n = 5 (1 in 43 959); mucopolysaccharidosis (MPS) type 1, n = 1 (1 in 219 793); and Niemann-Pick disease type A/B, n = 2 (1 in 109 897). Twenty-two infants had a positive screen for 1 of the 5 disorders but could not be classified as either affected or unaffected after follow-up testing, including genotyping. Pseudodeficiencies for alpha-L-iduronidase and alpha-glucosidase were detected more often than true deficiencies.

CONCLUSIONS

The incidences of Fabry disease and Pompe disease were significantly higher than published estimates, although most cases detected were predicted to be late onset. The incidences of Gaucher disease, MPS I, and Niemann-Pick disease were comparable with previously published estimates. A total of 16 infants could not be positively identified as either affected or unaffected. To validate the true risks and benefits of newborn screening for LSD, long term follow-up in these infants and those detected with later-onset disorders will be essential.

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.

The hidden Niemann-Pick type C patient: clinical niches for a rare inherited metabolic disease

BACKGROUND

Niemann-Pick disease type C (NP-C) is a rare, inherited neurodegenerative disease of impaired intracellular lipid trafficking. Clinical symptoms are highly heterogeneous, including neurological, visceral, or psychiatric manifestations. The incidence of NP-C is under-estimated due to under-recognition or misdiagnosis across a wide range of medical fields. New screening and diagnostic methods provide an opportunity to improve detection of unrecognized cases in clinical sub-populations associated with a higher risk of NP-C. Patients in these at-risk groups ("clinical niches") have symptoms that are potentially related to NP-C, but go unrecognized due to other, more prevalent clinical features, and lack of awareness regarding underlying metabolic causes.

METHODS

Twelve potential clinical niches identified by clinical experts were evaluated based on a comprehensive, non-systematic review of literature published to date. Relevant publications were identified by targeted literature searches of EMBASE and PubMed using key search terms specific to each niche. Articles published in English or other European languages up to 2016 were included.

FINDINGS

Several niches were found to be relevant based on available data: movement disorders (early-onset ataxia and dystonia), organic psychosis, early-onset cholestasis/(hepato)splenomegaly, cases with relevant antenatal findings or fetal abnormalities, and patients affected by family history, consanguinity, and endogamy. Potentially relevant niches requiring further supportive data included: early-onset cognitive decline, frontotemporal dementia, parkinsonism, and chronic inflammatory CNS disease. There was relatively weak evidence to suggest amyotrophic lateral sclerosis or progressive supranuclear gaze palsy as potential niches.

CONCLUSIONS

Several clinical niches have been identified that harbor patients at increased risk of NP-C.

Newborn screening for Fabry disease in the north-west of Spain

Fabry disease is an X-linked lysosomal storage disorder caused by the impairment of α-galactosidase A. Enzyme replacement therapy is available to treat patients, who often experience delayed diagnosis. A newborn screening for Fabry disease was performed to study the prevalence of the pathology and to evaluate the possibility to implement the test in systematic screenings. We collected 14,600 dried blood spot samples (7575 males and 7025 females) and carried out a diagnostic study by fluorometric measurement of α-galactosidase A enzymatic activity and GLA gene sequencing. We detected one patient with a mutation in GLA associated with classical Fabry Disease (M290I), ten subjects carrying genetic variants of uncertain diagnosis (S126G, R118C, A143T), and a girl with the non-characterized variant F18Y, which was not previously described. Additional 25 samples presented nucleotide substitutions described as polymorphisms (D313Y, rs2071225, and rs2071397). The estimated prevalence for Fabry disease in north-western Spanish males is of 0.013%.

CONCLUSION

These results confirm that the prevalence of Fabry disease is underestimated and systematic screening is feasible; however, further characterization of variants of uncertain clinical significance is necessary to establish protocols of patients' management. What is Known: • Fabry disease is a rare disease of delayed diagnosis, whose prevalence is underestimated. However, early diagnosis is important for better efficiency of the current available treatment. What is New: • This newborn screening for Fabry disease performed on Spanish population reveals a prevalence of genetic alterations in GLA of 0.1% in males (0.013% with classic Fabry disease) and also characterizes these modifications in order to discriminate between pathogenic mutations and genetic variants of unknown significance.

International differences in the evaluation of conditions for newborn bloodspot screening: a review of scientific literature and policy documents

Despite international adoption of newborn bloodspot screening (DBS), no two countries' screening programs are the same. This article aims to understand what factors influence DBS decision-making criteria and how conditions are assessed against them. In doing so, it offers unique insights into the international landscape of DBS. A systematic review on DBS criteria in scientific literature was first undertaken. Through this, five topics were identified for consideration when analyzing DBS decision-making. Using these five topics as a template, a side-by-side comparison was conducted on DBS in policy documents of eight countries. Programs are using different approaches to explore the same policy issues, including: the beneficiary of DBS, definition of criteria, the way conditions are assessed, level of evidence required, and recommendations after assessment. These differences have the potential to result in increased disparity across DBS internationally. Ultimately, governments need to decide on their role and develop an approach to DBS decision-making in line with this role. The analyses presented in this article highlight that despite programs' commonalities, no one 'DBS decision-making solution' exists. Understanding the different approaches to decision-making within the literature and policy settings, provides an objective starting point for structured decision-making approaches for DBS programs.

Tandem Mass Spectrometry of Sphingolipids: Applications for Diagnosis of Sphingolipidoses

In recent years, mass spectrometry (MS) has become the dominant technology in lipidomic analysis. It is widely used in diagnosis and research of lipid metabolism disorders including those characterized by impairment of lysosomal functions and storage of nondegraded-degraded substrates. These rare diseases, which include sphingolipidoses, have severe and often fatal clinical consequences. Modern MS methods have contributed significantly to achieve a definitive diagnosis, which is essential in clinical practice to begin properly targeted patient care. Here we summarize MS and tandem MS methods used for qualitative and quantitative analysis of sphingolipids (SL) relative to the diagnostic process for sphingolipidoses and studies focusing on alterations in cell functions due to these disorders. This review covers the following topics: Tandem MS is sensitive and robust in determining the composition of sphingolipid classes in various biological materials. Its ability to establish SL metabolomic profiles using MS bench-top analyzers, significantly benefits the first stages of a diagnosis as well as metabolic studies of these disorders. It can thus contribute to a better understanding of the biological significance of SL.

Patients' perspectives on newborn screening for later-onset lysosomal storage diseases

Lysosomal storage diseases (LSDs) are an individually rare but collectively common group of hereditary, progressive, multi-systemic disorders. Recent technological advances have brought newborn screening (NBS) for LSDs to attention in the United States. However, many LSD symptoms present in later childhood or adulthood, with a wide spectrum of severity. Because late-onset symptoms stray from the traditional NBS model, healthcare providers have expressed concerns about potential harm to patients and/or their families. In this study, 47 individuals with Fabry disease (FD), 22 with Gaucher disease (GD), and 22 with late-onset Pompe disease (LOPD) were surveyed regarding how their life might have been impacted by NBS. Of the 91 participants, none had symptoms at birth and 42 (46.7%) were symptom-free until adulthood. Over half (52.8%) were diagnosed ≥5years from symptom onset; of these, significantly more had FD (60%) or LOPD (63.6%) than GD (23.8%). However, length of diagnostic odyssey was not significantly correlated with opinion on NBS. Most participants either strongly agreed (45%) or agreed (33.3%) with NBS for their condition, with no significant differences between diseases. Opinions on NBS were correlated with participants' opinions on whether NBS would have resulted in better current health, but uncorrelated with disease severity or current life satisfaction. Significantly more participants with FD (42.6%) and LOPD (63.6%) than GD (13.6%) felt they would have greater life satisfaction had they been diagnosed as a newborn (p=0.007). Almost half (41%) of participants would have made different life decisions, including lifestyle, financial, and reproductive decisions. Regarding potential harm, participants were most concerned about insurability and least concerned about removal of children's autonomy. In conclusion, NBS is highly approved of among individuals with LSDs themselves, as it would significantly eliminate diagnostic odysseys and potentially alter life planning.

Biobank participant support of newborn screening for disorders with variable treatment and intervention options

We aimed to better understand biobank participant opinions of the benefits of newborn screening (NBS) for certain disorder types and how terminology used in NBS discourse might impact stakeholder opinion. We conducted a between-subjects randomized survey of 5840 members of the Northwestern University Biobank. The survey contained 12 scenarios, each describing a disorder and its treatment. For each scenario, we varied the terminology used to describe treatment options. One survey version used the term intervention and the other treatment. The outcome measured for each scenario was perceived benefit (for the infant) and importance of testing (for participants). Comparisons were made between participants and between scenarios. Ratings of benefit and importance were not influenced by the use of the term intervention versus treatment within scenarios. Nuances existed in ratings of benefit to the infant and importance to participants amongst scenarios. Participants were most likely to perceive benefit and importance in screening for a disorder if treatment/intervention offered a high chance of improved outcomes. While participants perceived benefit to the infant and importance to themselves in screening for most disorders, nuances in inter-scenario ratings suggest participants weighed availability and type of treatment/intervention in consideration of the benefits of NBS.

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).

Newborn screening for lysosomal storage disorders

Every newborn in the U.S. is screened for at least 29 disorders, where evidence suggests that early detection is possible and beneficial. With new or improved treatment options and development of high-throughput screening tests, additional conditions have been proposed for inclusion in newborn screening programs. Among those are several lysosomal storage disorders that have been evaluated in limited pilot studies or that are already included in a few national or international newborn screening programs. These conditions include Pompe disease, Niemann-Pick type A/B disease, Fabry disease, Krabbe disease, Mucopolysaccharidoses types I and II, and Gaucher disease. Here, we review the current state of newborn screening for these lysosomal storage disorders.

Pompe disease: literature review and case series

Pompe disease is a rare multi-systemic metabolic myopathy caused by autosomal recessive mutations in the acidic alpha glucosidase (GAA) gene. Significant progress had been made in the diagnosis and management of patients with Pompe disease. Here, we describe our experience with 12 patients with various forms of Pompe disease including 4 potentially pathogenic, novel GAA variants. We also review the recent the recent advances in the pathogenesis, diagnosis, and treatment of individuals with Pompe disease.

Stakeholder attitudes towards the role and application of informed consent for newborn bloodspot screening: a study protocol

INTRODUCTION

Newborn bloodspot screening (NBS) involves testing a small sample of blood taken from the heel of the newborn for a number of serious and life-limiting conditions. In Canada, newborn screening programmes fall under provincial and territorial jurisdiction with no federal coordination. To date, we know very little about the underlying beliefs around different consent practices or how terminology is interpreted by different individuals. Differences in attitudes may have important healthcare consequences. This study will provide empirical data comparing stakeholder opinions on their understanding of consent-related terminology, the perceived applicability of different consent approaches to newborn screening, and the requirements of these different approaches.

METHODS AND ANALYSIS

Parents, healthcare professionals and policymakers will be recruited in the provinces of Ontario and Newfoundland and Labrador. Parents will be identified through records held by each provincial screening programme. Healthcare professionals will be purposively sampled on the basis of engagement with newborn screening. Within each province we will identify policymakers who have policy analysis or advisory responsibilities relating to NBS. Data collection will be by qualitative interviews. We will conduct 20 interviews with parents of young children, 10 interviews with key healthcare professionals across the range of appropriate specialties and 10 with policymakers at each site (40 per site, total, N=80). The examination of the transcripts will follow a thematic analysis approach. Recruitment started in June 2014 and is expected to be complete by June 2015.

ETHICS AND DISSEMINATION

This study received ethics approval from the Ottawa Health Science Network Research Ethics Board, the Children's Hospital of Eastern Ontario Research Ethics Board (both Ontario), and the Health Research Ethics Authority (Newfoundland and Labrador).

RESULTS

These will be reported in peer-reviewed publications and conference presentations. The results will have specific application to the development of parent education materials for newborn screening.

The oxidative molecular regulation mechanism of NOX in children with phenylketonuria

Phenylketonuria (PKU) is the most frequent inherited disorder of amino acid metabolism. In our previous work, we investigated the role of NADPH oxidase (NOX) in a Pahenu2-BTBR PKU mouse model, and an in vitro cell culture model of PKU. In the current study, we evaluated various oxidative stress parameters, namely total antioxidant capacity (T-AOC), glutathione (GSH) and maleic dialdehyde (MDA) in the plasma of 40 PKU children, for further investigating the oxidative molecular regulation mechanism of NOX in PKU. It was observed that T-AOC and GSH markedly decreased in PKU as compared with the control group (P<0.01), and seemed to correlate negatively with Phe level. However, there was no statistical difference in MDA level among the three groups. And 8-isoprostane in the blood samples of PKU2 groups was slightly higher than control group (P<0.05). Additionally, mRNA levels of subunits of NOX included p47(phox) and p67(phox) significantly increased in PKU group (P<0.01). These results reflected that NOX is the important source of reactive oxygen species and is involved in the oxidative molecular regulation mechanism in PKU, which shows a new perspective toward understanding the biological underpinnings of PKU.

Newborn screening for pompe disease? a qualitative study exploring professional views

Background

Developments in enzyme replacement therapy have kindled discussions on adding Pompe disease, characterized by progressive muscle weakness and wasting, to neonatal screening. Pompe disease does not fit traditional screening criteria as it is a broad-spectrum phenotype disorder that may occur in lethal form in early infancy or manifest in less severe forms from infancy to late adulthood. Current screening tests cannot differentiate between these forms. Normally, expanding screening is discussed among experts in advisory bodies. While advisory reports usually mention the procedures and outcome of deliberations, little is known of the importance attached to different arguments and the actual weighing processes involved. In this research we aim to explore the views of a wide range of relevant professionals to gain more insight into the process of weighing pros and cons of neonatal screening for Pompe disease, as an example of the dilemmas involved in screening for broad-spectrum phenotype disorders.

Methods

We conducted 24 semi-structured interviews with medical, lab, insurance and screening professionals, and executive staff of patient organisations. They were asked about their first reaction to neonatal screening for Pompe disease, after which benefits and harms and requirements for screening were explored in more detail.

Results

Advantages included health gain by timely intervention, avoiding a diagnostic quest, having a reproductive choice and gaining more knowledge about the natural course and treatment. Being prepared was mentioned as an advantage for the later manifesting cases. Disadvantages included treatment costs and uncertainties about its effect, the timing of treatment in later manifesting cases, the psychological burden for the patient-in-waiting and the family. Also the downsides of having prior knowledge as well as having to consider a reproductive option were mentioned as disadvantages.

Conclusion

When weighing pros and cons, interviewees attach different importance to different arguments, based on personal and professional views. Professionals expect benefits from neonatal screening for Pompe disease, especially for early-onset cases. Some interviewees valued screening in later manifesting cases as well, while stressing the need for adequate support of pre-symptomatic patients and their families. Others considered the psychological burden and uncertainties regarding treatment as reasons not to screen.

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.

Inborn errors of metabolism and expanded newborn screening: review and update

Inborn errors of metabolism (IEM) are a phenotypically and genetically heterogeneous group of disorders caused by a defect in a metabolic pathway, leading to malfunctioning metabolism and/or the accumulation of toxic intermediate metabolites. To date, more than 1000 different IEM have been identified. While individually rare, the cumulative incidence has been shown to be upwards of 1 in 800. Clinical presentations are protean, complicating diagnostic pathways. IEM are present in all ethnic groups and across every age. Some IEM are amenable to treatment, with promising outcomes. However, high clinical suspicion alone is not sufficient to reduce morbidities and mortalities. In the last decade, due to the advent of tandem mass spectrometry, expanded newborn screening (NBS) has become a mandatory public health strategy in most developed and developing countries. The technology allows inexpensive simultaneous detection of more than 30 different metabolic disorders in one single blood spot specimen at a cost of about USD 10 per baby, with commendable analytical accuracy and precision. The sensitivity and specificity of this method can be up to 99% and 99.995%, respectively, for most amino acid disorders, organic acidemias, and fatty acid oxidation defects. Cost-effectiveness studies have confirmed that the savings achieved through the use of expanded NBS programs are significantly greater than the costs of implementation. The adverse effects of false positive results are negligible in view of the economic health benefits generated by expanded NBS and these could be minimized through increased education, better communication, and improved technologies. Local screening agencies should be given the autonomy to develop their screening programs in order to keep pace with international advancements. The development of biochemical genetics is closely linked with expanded NBS. With ongoing advancements in nanotechnology and molecular genomics, the field of biochemical genetics is still expanding rapidly. The potential of tandem mass spectrometry is extending to cover more disorders. Indeed, the use of genetic markers in T-cell receptor excision circles for severe combined immunodeficiency is one promising example. NBS represents the highest volume of genetic testing. It is more than a test and it warrants systematic healthcare service delivery across the pre-analytical, analytical, and post-analytical phases. There should be a comprehensive reporting system entailing genetic counselling as well as short-term and long-term follow-up. It is essential to integrate existing clinical IEM services with the expanded NBS program to enable close communication between the laboratory, clinicians, and allied health parties. In this review, we will discuss the history of IEM, its clinical presentations in children and adult patients, and its incidence among different ethnicities; the history and recent expansion of NBS, its cost-effectiveness, associated pros and cons, and the ethical issues that can arise; the analytical aspects of tandem mass spectrometry and post-analytical perspectives regarding result interpretation.

The evolution of blood-spot newborn screening

Over 50 years after the introduction of a blood-spot newborn screening test using the bacterial-inhibition assay (BIA), blood-spot newborn screening has evolved into complex public service scientific programmes. For several decades, many patients with phenylketonuria (PKU), congenital hypothyroidism (CH), cystic fibrosis (CF) and hemoglobinopathy disorders have benefited from early intervention across the world. In the last 20 years, there have been great changes in laboratory techniques and high-throughput data handling meaning that a huge spectrum of disorders can be identified from an increasing population. This coupled with the fact that there are an increasing number of therapies for specific rare disorders mean that health services may become inundated with complex and expensive demands in the future. Some of these issues have been realised in the implementation of multiplex assay such as electrospray tandem mass spectrometry (MSMS) programmes but will be much more exaggerated if genomic sequencing screening becomes a reality. In this context, the core-principles for implementation of newborn screening tests remain as important today as they have in the past when new tests are considered as part of the blood-spot screening programme.

Identification of infants at risk for developing Fabry, Pompe, or mucopolysaccharidosis-I from newborn blood spots by tandem mass spectrometry

OBJECTIVE

To assess the performance of a tandem mass spectrometry (MS/MS) technology in a newborn screening laboratory to simultaneously measure α-galactosidase, acid-α-glucosidase, and α-L-iduronidase for the detection of infants at risk to develop Fabry, Pompe, or mucopolysaccharidosis (MPS)-I diseases.

STUDY DESIGN

Enzyme activity was assayed from a 3.2-mm punch from 100,000+ anonymous newborn blood spots. Punches with low enzyme activity were further evaluated by nucleotide sequence analysis of the responsible gene. Confirmation of affected infants was dependent on identification of mutations compatible with diminished enzyme activity.

RESULTS

The technology for simultaneously measuring multiple enzyme activities by MS/MS was successful. The confirmation of diagnosis for Fabry, Pompe, or MPS-I, by DNA sequencing estimated the prevalence of Fabry disease at 1/7800 males (95% CI 1/17,800-1/3600); Pompe disease at 1/27,800 newborns (95% CI 1/90,000-1/10,200); and MPS-I at 1/35,500 newborns (95% CI 1/143,000-1/11,100). These estimates of prevalence are 2 to 4 times greater than the prevalence estimated by clinical diagnosis. The combined prevalence for the 3 disorders was 1/7500 newborns (95% CI 1/13,500-1/4500).

CONCLUSIONS

MS/MS for the simultaneous assay of multiple lysosomal enzymes can be successfully introduced into a routine newborn screening laboratory. The technology has a positive predictive value equal to, or better, than methods currently used for the detection of nonlysosomal disorders. Using newborn blood spots, the combined prevalence of Fabry, Pompe, and MPS-I is estimated at 1/7500 newborns based on low-enzyme activity and confirmation by mutation analysis.

Expanded newborn screening and confirmatory follow-up testing for inborn errors of metabolism detected by tandem mass spectrometry

Newborn screening (NBS) of inborn errors of metabolism (IEM) is a coordinated comprehensive system consisting of education, screening, follow-up of abnormal test results, confirmatory testing, diagnosis, treatment, and evaluation of periodic outcome and efficiency. The ultimate goal of NBS and follow-up programs is to reduce morbidity and mortality from the disorders. Over the past decade, tandem mass spectrometry (MS/MS) has become a key technology in the field of NBS. It has replaced classic screening techniques of one-analysis, one-metabolite, one-disease with one analysis, many-metabolites, and many-diseases. The development of electrospray ionization (ESI), automation of sample handling and data manipulation have allowed the introduction of expanded NBS for the identification of numerous conditions on a single sample and new conditions to be added to the list of disorders being screened for using MS/MS. In the case of a screened positive result, a follow-up analytical test should be performed for confirmation of the primary result. The most common confirmatory follow-up tests are amino acids and acylcarnitine analysis in plasma and organic acid analysis in urine. NBS should be integrated with follow-up and clinical management. Recent improvements in therapy have caused some disorders to be considered as potential candidates for NBS. This review covers some of the basic theory of expanded MS/MS and follow-up confirmatory tests applied for NBS of IEM.

NOX, the main regulator in oxidative stress in experimental models of phenylketonuria?

AIM

To reveal the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) in the integration of the redox signal in the oxidative molecular regulation mechanism in phenylketonuria (PKU).

METHODS

The blood samples were obtained from Pahenu2-BTBR PKU and wild-type mice, respectively. Phe concentration, total antioxidant capacity (T-AOC), glutathione (GSH) and maleic dialdehyde (MDA) were analyzed. After collection of the mononuclear cells, reverse transcription polymerase chain reaction (RT-PCR) for NOX was performed. In addition, NOX activity and superoxide in mononuclear cells were determined.

RESULTS

Compared to the control group, Phe concentration, T-AOC and MDA were markedly increased in PKU mice (p<0.01, p<0.05, p<0.01, respectively). However, the GSH level in PKU mice was less than that in control group (p<0.05). The mRNA level of subunits of NOX included p47phox and p67phox, were increased in PKU mice (p<0.05), however, the gp91phox had no obvious change in the two groups (p>0.05). NOX activity and superoxide were also remarkably elevated in PKU mice (p<0.05).

CONCLUSION

NOX may play an important role in the integration of the redox signal in the oxidative molecular regulation mechanism in PKU.

Experiences of parents and patients with the timing of Mucopolysaccharidosis type I (MPS I) diagnoses and its relevance to the ethical debate on newborn screening

INTRODUCTION

Newborn screening (NBS) techniques have been developed for several lysosomal storage disorders (LSDs), including Mucopolysaccharidosis type I (MPS I). MPS I is an LSD with a wide phenotypic spectrum that ranges from the severe Hurler phenotype to the attenuated Scheie phenotype. To improve the ethical discussion about NBS for MPS I, we performed an interview study to explore the experiences of MPS I patients and their parents with the timings of their diagnoses.

METHODS

We used a qualitative research approach consisting of 17 interviews with the parents of patients with all MPS I phenotypes and with patients with attenuated forms of MPS I. The interviews were audio-recorded, transcribed and subsequently analyzed to identify the main themes identified by the participants.

RESULTS

Five important themes, focusing on the experienced disadvantages of delayed diagnosis and the advantages and disadvantages of a hypothetical earlier diagnosis, were identified in our group of participants: 1) delayed diagnosis causing parental frustration, 2) delayed diagnosis causing patient frustration, 3) early diagnosis enabling reproductive decision-making, 4) early diagnosis enabling focusing on the diagnosis, and 5) early diagnosis enabling timely initiation of treatment. There was a remarkable similarity in the experiences with timing of diagnosis between parents of patients with the severe and the attenuated forms.

CONCLUSION

This was the first study to explore the personal experiences of MPS I patients and their parents with diagnostic timing. Our study identified five important themes that are highly relevant to the ethical discussion on expanding NBS programs for MPS I.