Genome-wide sequencing in acutely ill infants: genomic medicine's critical application?

How Neonatologists Use Genetic Information

OBJECTIVE

To delineate specific ways in which neonatologists integrate genetic information into their clinical decision making.

STUDY DESIGN

We employed chart-stimulated recall, in which neonatologists described how they used genetic tests in specific patient cases, as well as semi-structured questioning about genetic information.

RESULTS

Based on 28 interviews with neonatologists, we document 6 uses of genetic information: making a diagnosis, categorizing/stereotyping as "genetic," informing prognosis, influencing treatment, informing goals of care, and supporting accountability. Both specific genetic diagnoses as well as a general categorization as "genetic" help neonatologists make sense of unusual clinical situations and calibrate their predictions about the future. Predictions, in turn, inform goals of care decisions, the timing of medical technology placement, and neonatologists' self-evaluations. Diagnoses rarely influence day-to-day treatment directly. Neonatologists assign great value to improved prognostication, but simultaneously feel a responsibility to ensure that genetic information is not applied in ways that are overly deterministic or reflect ableism.

CONCLUSIONS

Frameworks for measuring successes and failures of genetic information in the neonatal intensive care unit need to be aligned with the ways neonatologists use this information. Understanding neonatologists' use creates opportunity to maximize benefit and reduce bias in applying this complex information.

Should secondary pharmacogenomic variants be actively screened and reported when diagnostic genome-wide sequencing is performed in a child?

This white paper was prepared by the Global Alliance for Genomics and Health Regulatory and Ethics Work Stream's Pediatric Task Team to review and provide perspective with respect to ethical, legal, and social issues regarding the return of secondary pharmacogenomic variants in children who have a serious disease or developmental disorder and are undergoing exome or genome sequencing to identify a genetic cause of their condition. We discuss actively searching for and reporting pharmacogenetic/genomic variants in pediatric patients, different methods of returning secondary pharmacogenomic findings to the patient/parents and/or treating clinicians, maintaining these data in the patient's health record over time, decision supports to assist using pharmacogenetic results in future treatment decisions, and sharing information in public databases to improve the clinical interpretation of pharmacogenetic variants identified in other children. We conclude by presenting a series of points to consider for clinicians and policymakers regarding whether, and under what circumstances, routine screening and return of pharmacogenomic variants unrelated to the indications for testing is appropriate in children who are undergoing genome-wide sequencing to assist in the diagnosis of a suspected genetic disease.

Hospital-level variation in genetic testing in children's hospitals' neonatal intensive care units from 2016 to 2021

PURPOSE

This study aimed to examine variation in genetic testing between neonatal intensive care units (NICUs) across hospitals over time.

METHODS

We performed a multicenter large-scale retrospective cohort study using NICU discharge data from the Pediatric Hospital Information System database between 2016 and 2021. We analyzed the variation in the percentage of NICU patients who had any genetic testing across hospitals and over time. We used a multivariable multilevel logistic regression model to investigate the potential association between patient characteristics and genetic testing.

RESULTS

The final analysis included 207,228 neonates from 38 hospitals. Overall, 13% of patients had at least 1 genetic test sent, although this varied from 4% to 50% across hospitals. Over the study period, the proportion of patients tested increased, with the increase disproportionately borne by hospitals already testing high proportions of patients. On average, patients who received genetic testing had higher illness severity. Controlling for severity, however, only minimally reduced the degree of hospital-level variation in genetic testing.

CONCLUSION

The percentage of NICU patients who undergo genetic testing varies among hospitals and increasingly so over time. Variation is largely unexplained by differences in severity between hospitals. The degree of variation suggests that clearer guidelines for NICU genetic testing are warranted.

BLEND: a fast, memory-efficient and accurate mechanism to find fuzzy seed matches in genome analysis

Generating the hash values of short subsequences, called seeds, enables quickly identifying similarities between genomic sequences by matching seeds with a single lookup of their hash values. However, these hash values can be used only for finding exact-matching seeds as the conventional hashing methods assign distinct hash values for different seeds, including highly similar seeds. Finding only exact-matching seeds causes either (i) increasing the use of the costly sequence alignment or (ii) limited sensitivity. We introduce BLEND, the first efficient and accurate mechanism that can identify both exact-matching and highly similar seeds with a single lookup of their hash values, called fuzzy seed matches. BLEND (i) utilizes a technique called SimHash, that can generate the same hash value for similar sets, and (ii) provides the proper mechanisms for using seeds as sets with the SimHash technique to find fuzzy seed matches efficiently. We show the benefits of BLEND when used in read overlapping and read mapping. For read overlapping, BLEND is faster by 2.4×-83.9× (on average 19.3×), has a lower memory footprint by 0.9×-14.1× (on average 3.8×), and finds higher quality overlaps leading to accurate de novo assemblies than the state-of-the-art tool, minimap2. For read mapping, BLEND is faster by 0.8×-4.1× (on average 1.7×) than minimap2. Source code is available at https://github.com/CMU-SAFARI/BLEND.

Rapid Genetic Testing in Pediatric and Neonatal Critical Care: A Scoping Review of Emerging Ethical Issues

BACKGROUND

Rapid genome-wide sequencing (rGWS) is being increasingly used to aid in prognostication and decision-making for critically ill newborns and children. Although its feasibility in this fast-paced setting has been described, this new paradigm of inpatient genetic care raises new ethical challenges.

OBJECTIVE

A scoping review was performed to (1) identify salient ethical issues in this area of practice; and (2) bring attention to gaps and ethical tensions that warrant more deliberate exploration.

METHODS

Data sources, Ovid Medline and Cochrane Central Register of Controlled Trials, were searched up to November 2021. Articles included were those in English relating to rGWS deployed rapidly in a critical care setting. Publications were examined for ethical themes and were further characterized as including a superficial or in-depth discussion of that theme. New themes were inductively identified as they emerged.

RESULTS

Ninety-nine studies, published in 2012 or thereafter, met inclusion criteria. Themes identified elaborated upon established ethical principles related to beneficence and nonmaleficence (ie, clinical utility, medical uncertainty, impact on family, and data security) autonomy (ie, informed consent), and justice (ie, resource allocation and disability rights). Many themes were only narrowly discussed.

CONCLUSIONS

The application of rGWS in neonatal and pediatric acute care is inherently tied to ethically charged issues, some of which are reported here. Attention to the ethical costs and benefits of rGWS is not always discussed, with important gaps and unanswered questions that call for ongoing focus on these ethical considerations in this next application of acute care genomics.

Using the Sankey diagram to visualize article features on the topics of whole-exome sequencing (WES) and whole-genome sequencing (WGS) since 2012: Bibliometric analysis

BACKGROUND

Sequencing technologies, such as whole-exome sequencing (WES) and whole-genome sequencing (WGS), have been increasingly applied to medical research in recent years. Which countries, journals, and institutes (called entities) contributed most to the fields (WES/WGS) remains unknown. Temporal bar graphs (TBGs) are frequently used in trend analysis of publications. However, how to draw the TBG on the Sankey diagram is not well understood in bibliometrics. We thus aimed to investigate the evolution of article entities in the WES/WGS fields using publication-based TBGs and compare the individual research achievements (IRAs) among entities.

METHODS

A total of 3599 abstracts downloaded from icite analysis were matched to entities, including article identity numbers, citations, publication years, journals, affiliated countries/regions of origin, and medical subject headings (MeSH terms) in PubMed on March 12, 2022. The relative citation ratio (RCR) was extracted from icite analysis to compute the hT index (denoting the IRA, taking both publications and citations into account) for each entity in the years between 2012 and 2021. Three types of visualizations were applied to display the trends of publications (e.g., choropleth maps and the enhanced TBGs) and IRAs (e.g., the flowchart on the Sankey diagram) for article entities in WES/WGS.

RESULTS

We observed that the 3 countries (the US, China, and the UK) occupied most articles in the WES/WGS fields since 2012, the 3 entities (i.e., top 5 journals, research institutes, and MeSH terms) were demonstrated on the enhanced TBGs, the top 2 MeSH terms were genetics and methods in WES and WGS, and the IRAs of 6 article entities with their hT-indices were succinctly and simultaneously displayed on a single Sankey diagram that was never launched in bibliographical studies.

CONCLUSION

The number of WES/WGS-related articles has dramatically increased since 2017. TBGs, particularly with hTs on the Sankey, are recommended for research on a topic (or in a discipline) to compare trends of publications and IRAs for entities in future bibliographical studies.

From molecules to genomic variations: Accelerating genome analysis via intelligent algorithms and architectures

We now need more than ever to make genome analysis more intelligent. We need to read, analyze, and interpret our genomes not only quickly, but also accurately and efficiently enough to scale the analysis to population level. There currently exist major computational bottlenecks and inefficiencies throughout the entire genome analysis pipeline, because state-of-the-art genome sequencing technologies are still not able to read a genome in its entirety. We describe the ongoing journey in significantly improving the performance, accuracy, and efficiency of genome analysis using intelligent algorithms and hardware architectures. We explain state-of-the-art algorithmic methods and hardware-based acceleration approaches for each step of the genome analysis pipeline and provide experimental evaluations. Algorithmic approaches exploit the structure of the genome as well as the structure of the underlying hardware. Hardware-based acceleration approaches exploit specialized microarchitectures or various execution paradigms (e.g., processing inside or near memory) along with algorithmic changes, leading to new hardware/software co-designed systems. We conclude with a foreshadowing of future challenges, benefits, and research directions triggered by the development of both very low cost yet highly error prone new sequencing technologies and specialized hardware chips for genomics. We hope that these efforts and the challenges we discuss provide a foundation for future work in making genome analysis more intelligent.

Measures of Utility Among Studies of Genomic Medicine for Critically Ill Infants: A Systematic Review

IMPORTANCE

Genomic medicine holds promise to revolutionize care for critically ill infants by tailoring treatments for patients and providing additional prognostic information to families. However, measuring the utility of genomic medicine is not straightforward and has important clinical and ethical implications.

OBJECTIVE

To review the ways that researchers measure or neglect to measure the utility of genomic medicine for critically ill infants.

EVIDENCE REVIEW

This systematic review included prospective full-text studies of genomic medicine of both whole exome and genome sequencing in critically ill infants younger than 1 year. PubMed, Embase, Scopus, and Cochrane Library databases, the Cochrane Database of Systematic Reviews, and the ClinicalTrials.gov register were searched with an English language restriction for articles published from the inception of each database through May 2022. Search terms included variations of the following: gene, sequencing, intensive care, critical care, and infant. From the included articles, information on how utility was defined and measured was extracted and synthesized. Information was also extracted from patient cases that authors highlighted by providing additional information. Spearman rank-order correlation was used to evaluate the association between study size and utility.

FINDINGS

Synthesized data from the 21 included studies reflected results from 1654 patients. A mean of 46% (range, 15%-72%) of patients had a positive genetic test result, and a mean of 37% (range, 13%-61%) met the criteria for experiencing utility. Despite heterogeneity in how studies measured and reported utility, a standardized framework was created with 5 categories of utility: treatment change, redirection of care, prognostic information, reproductive information, and screening or subspecialty referral. Most studies omitted important categories of utility, notably personal utility (patient-reported benefits) (20 studies [95%]), utility of negative or uncertain results (15 [71%]), and disutility (harms) (20 [95%]). Studies disproportionally highlighted patient cases that resulted in treatment change. Larger studies reported substantially lower utility (r = -0.65; P = .002).

CONCLUSIONS AND RELEVANCE

This systematic review found that genomic medicine offered various categories of utility for a substantial proportion of critically ill infants. Studies measured utility in heterogeneous ways and focused more on documenting change than assessing meaningful benefit. Authors' decisions about which cases to highlight suggest that some categories of utility may be more important than others. A more complete definition of utility that is used consistently may improve understanding of potential benefits and harms of genetic medicine.

Real-world economic evaluation of prospective rapid whole-genome sequencing compared to a matched retrospective cohort of critically ill pediatric patients in the United States

There is an increasing demand for supporting the adoption of rapid whole-genome sequencing (rWGS) by demonstrating its real-world value. We aimed to assess the cost-effectiveness of rWGS in critically ill pediatric patients with diseases of unknown cause. Data were collected prospectively of patients admitted to the Nicklaus Children's Hospital's intensive care units from March 2018 to September 2020, with rWGS (N = 65). Comparative data were collected in a matched retrospective cohort with standard diagnostic genetic testing. We determined total costs, diagnostic yield (DY), and incremental cost-effectiveness ratio (ICER) adjusted for selection bias and right censoring. Sensitivity analyses explored the robustness of ICER through bootstrapping. rWGS resulted in a diagnosis in 39.8% while standard testing in 13.5% (p = 0.026). rWGS resulted in a mean saving per person of $100,440 (SE = 26,497, p < 0.001) and a total of $6.53 M for 65 patients. rWGS in critically ill pediatric patients is cost-effective, cost-saving, shortens diagnostic odyssey, and triples the DY of traditional approaches.

Perspectives of United States neonatologists on genetic testing practices

PURPOSE

Genetic disorders often present in the neonatal intensive care unit (NICU), and detecting or confirming these diagnoses has been shown to impact care. However, the availability and use of genetic testing, particularly exome or genome sequencing, among NICUs varies widely. We therefore sought to investigate practice patterns related to genetic testing in NICUs around the country to identify and quantify potential discrepancies.

METHODS

We designed a survey that was distributed to neonatologists via email. The survey contained questions related to test availability and desirability, the process of test ordering in NICU, and general comfort with ordering and interpreting genetic testing. Demographic data related to the survey participants and characteristics of their NICU were also obtained.

RESULTS

In total, 162 neonatologists completed the survey, representing 40 states and 112 distinct NICUs. Although nearly all (93.2%) neonatologists attributed a high level of importance to identifying a genetic diagnosis for their patients, genetic consultations were only available at 78% of NICUs and exome or genome sequencing was not available on a regular basis (69% of NICUs).

CONCLUSION

Although, among US neonatologists surveyed, most feel that genetic tests are indicated for their patients, these are not always clinically available. Further research into implementation barriers is warranted.

The effect of rapid exome sequencing on downstream health care utilization for infants with suspected genetic disorders in an intensive care unit

PURPOSE

This study aimed to compare downstream utilization of medical services among critically ill infants admitted to intensive care units who received rapid exome sequencing (ES) and those who followed alternative diagnostic testing pathways.

METHODS

Using propensity score-weighted regression models including sex, age at admission, and severity indicators, we compared a group of 47 infants who underwent rapid ES with a group of 211 infants who did not receive rapid ES. Utilization and cost indicators were compared between cohorts using negative binomial models for utilization and two-part models for costs.

RESULTS

After controlling for patients' sociodemographic and clinical characteristics, we found no statistically significant difference in outpatient visits, hospitalizations, intensive care unit or total length of stay, or length of stay-associated costs between the cohorts at 12- or 26-month follow-up. Similarly, there was no evidence of higher utilization or costs by the ES group when infants who died were removed from the analysis.

CONCLUSION

When examining utilization during and beyond the diagnostic trajectory, there is no evidence that ES changes frequency of outpatient visits or use of in-hospital resources in critically ill infants with suspected genetic disorders.

Genome sequencing as a first-line diagnostic test for hospitalized infants

PURPOSE

SouthSeq is a translational research study that undertook genome sequencing (GS) for infants with symptoms suggestive of a genetic disorder. Recruitment targeted racial/ethnic minorities and rural, medically underserved areas in the Southeastern United States, which are historically underrepresented in genomic medicine research.

METHODS

GS and analysis were performed for 367 infants to detect disease-causal variation concurrent with standard of care evaluation and testing.

RESULTS

Definitive diagnostic (DD) or likely diagnostic (LD) genetic findings were identified in 30% of infants, and 14% of infants harbored an uncertain result. Only 43% of DD/LD findings were identified via concurrent clinical genetic testing, suggesting that GS testing is better for obtaining early genetic diagnosis. We also identified phenotypes that correlate with the likelihood of receiving a DD/LD finding, such as craniofacial, ophthalmologic, auditory, skin, and hair abnormalities. We did not observe any differences in diagnostic rates between racial/ethnic groups.

CONCLUSION

We describe one of the largest-to-date GS cohorts of ill infants, enriched for African American and rural patients. Our results show the utility of GS because it provides early-in-life detection of clinically relevant genetic variations not detected by current clinical genetic testing, particularly for infants exhibiting certain phenotypic features.

Influence of Genetic Information on Neonatologists' Decisions: A Psychological Experiment

BACKGROUND AND OBJECTIVES

Genetic testing is expanding among ill neonates, yet the influence of genetic results on medical decision-making is not clear. With this study, we sought to determine how different types of genetic information with uncertain implications for prognosis influence clinicians' decisions to recommend intensive versus palliative care.

METHODS

We conducted a national study of neonatologists using a split sample experimental design. The questionnaire contained 4 clinical vignettes. Participants were randomly assigned to see one of 2 versions that varied only regarding whether they included the following genetic findings: (1) a variant of uncertain significance; (2) a genetic diagnosis that affects neurodevelopment but not acute survival; (3) a genetic versus nongenetic etiology of equally severe pathology; (4) a pending genetic testing result. Physicians answered questions about recommendations they would make for the patient described in each vignette.

RESULTS

Vignette versions that included a variant of uncertain significance, a diagnosis foreshadowing neurodevelopmental impairment, or a genetic etiology of disease were all associated with an increased likelihood of recommending palliative rather than intensive care. A pending genetic test result did not have a significant effect on care recommendations.

CONCLUSIONS

Findings from this study of hypothetical cases suggest neonatologists apply uncertain genetic findings or those that herald neurodevelopmental disability in problematic ways. As genetic testing expands, understanding how it is used in decision-making and educating clinicians regarding appropriate use are paramount.

The full spectrum of ethical issues in pediatric genome-wide sequencing: a systematic qualitative review

Background

The use of genome-wide sequencing in pediatric medicine and research is growing exponentially. While this has many potential benefits, the normative and empirical literature has highlighted various ethical issues. There have not been, however, any systematic reviews of these issues. The aim of this systematic review is to determine systematically the spectrum of ethical issues that is raised for stakeholders in in pediatric genome-wide sequencing.

Methods

A systematic review in PubMed and Google Books (publications in English or German between 2004 and 2021) was conducted. Further references were identified via reference screening. Data were analyzed and synthesized using qualitative content analysis. Ethical issues were defined as arising when a relevant normative principle is not adequately considered or when two principles come into conflict.

Results

Our literature search retrieved 3175 publications of which 143 were included in the analysis. Together these mentioned 106 ethical issues in pediatric genome-wide sequencing, categorized into five themes along the pediatric genome-wide sequencing lifecycle. Most ethical issues identified in relation to genome-wide sequencing typically reflect ethical issues that arise in general genetic testing, but they are often amplified by the increased quantity of data obtained, and associated uncertainties. The most frequently discussed ethical aspects concern the issue of unsolicited findings.

Conclusion

Concentration of the debate on unsolicited findings risks overlooking other ethical challenges. An overarching difficulty presents the terminological confusion: both with regard to both the test procedure/ the scope of analysis, as well as with the topic of unsolicited findings. It is important that the genetics and ethics communities together with other medical professions involved work jointly on specific case related guidelines to grant the maximum benefit for the care of the children, while preventing patient harm and disproportionate overload of clinicians and the healthcare system by the wealth of available options and economic incentives to increase testing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02830-w.

Parental Attitudes Toward Clinical Genomic Sequencing in Children With Critical Cardiac Disease

OBJECTIVES

Through improving diagnostics and prognostics genomic sequencing promises to significantly impact clinical decisions for children with critical cardiac disease. Little is known about how families of children with critical cardiac disease perceive the impact of genomic sequencing on clinical care choices.

DESIGN

Qualitative interview study.

SETTING

A high-volume, tertiary pediatric heart center.

SUBJECTS

Families of children with critical cardiac disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thematic analysis of interview response content. Thirty-five families were interviewed. Three themes emerged: 1) benefits versus challenges of having genomic sequencing results, and 2) fears of clinical applications of genomic sequencing, and 3) nonclinical fears related to genomic sequencing. Participants struggled with perceived uses of genomic sequencing-derived knowledge. They described comfort in foreknowledge of their child's likely disease course but articulated significant apprehension around participating in care decisions with limited knowledge of genomic sequencing, genomic sequencing uses to inform clinical resource rationing decisions, and genomic sequencing uses by third parties impacting financial pressures families experience caring for a child with critical cardiac disease.

CONCLUSIONS

Families' perceptions of genomic sequencing uses in critical cardiac disease appear to strain their overall trust in the health system. Erosion of trust is concerning because the potential of genomic sequencing in critical cardiac disease will be unrealized if families are unwilling to undergo genomic sequencing, let alone to participate in the ongoing research needed to link genomic sequencing variants to clinical outcomes. Our findings may have implications for genomic sequencing use in children with other critical, high-acuity diseases.

Uncertain, Not Unimportant: Callosal Dysgenesis and Variants of Uncertain Significance in ROBO1

Congenital anomalies affect 3% to 5% of births and remain the leading cause of infant death in the United States. As whole exome and genome sequencing are increasingly used to diagnose underlying genetic disease, the patient's clinical presentation remains the most important context for interpreting sequencing results, including frequently reported variants of uncertain significance (VUS). Classification of a variant as VUS acknowledges limits on evidence to establish whether a variant can be classified as pathogenic or benign according to the American College of Medical Genetics guidelines. Importantly, the VUS designation reflects limits on the breadth of evidence linking the genetic variant to a disease. However, available evidence, although limited, may be surprisingly relevant in an individual patient's case. Accordingly, a VUS result should be approached neither as nondiagnostic genetic result nor as automatically "uncertain" in its potential to guide clinical decision-making. In this article, we discuss a case of an infant born at 29 weeks 4 days without a corpus callosum, whose whole genome sequencing yielded compound heterozygous variants both classified as VUS in ROBO1, a gene encoding for a receptor involved in a canonical signaling mechanism that guides axons across midline. Approaching the VUS result as potentially pathogenic, we found the infant ultimately had pituitary dysfunction and renal anomalies consistent with other reported ROBO1 variants and basic science literature. Accordingly, we highlight resources for variant interpretation available to clinicians to evaluate VUS results, particularly as they inform the diagnosis of individually rare but collectively common rare diseases.

Preferences and values for rapid genomic testing in critically ill infants and children: a discrete choice experiment

Healthcare systems are increasingly considering widespread implementation of rapid genomic testing of critically ill children, but evidence on the value of the benefits generated is lacking. This information is key for an optimal implementation into healthcare systems. A discrete choice experiment survey was designed to elicit preferences and values for rapid genomic testing in critically ill children. The survey was administered to members of the Australian public and families with lived experience of rapid genomic testing. A Bayesian D-efficient explicit partial profiles design was used, and data were analysed using a panel error component mixed logit model. Preference heterogeneity was explored using a latent class model and fractional logistic regressions. The public (n = 522) and families with lived experiences (n = 25) demonstrated strong preferences for higher diagnostic yield and clinical utility, faster result turnaround times, and lower cost. Society on average would be willing to pay an additional AU$9510 (US$6657) for rapid (2 weeks results turnaround time) and AU$11,000 (US$7700) for ultra-rapid genomic testing (2 days turnaround time) relative to standard diagnostic care. Corresponding estimates among those with lived experiences were AU$10,225 (US$7158) and AU$11,500 (US$8050), respectively. Our work provides further evidence that rapid genomic testing for critically ill children with rare conditions generates substantial utility. The findings can be used to inform cost-benefit analyses as part of broader healthcare system implementation.

The Use of Whole Genome and Exome Sequencing for Newborn Screening: Challenges and Opportunities for Population Health

Newborn screening (NBS) is a population-based program with a goal of reducing the burden of disease for conditions with significant clinical impact on neonates. Screening tests were originally developed and implemented one at a time, but newer methods have allowed the use of multiplex technologies to expand additions more rapidly to standard panels. Recent improvements in next-generation sequencing are also evolving rapidly from first focusing on individual genes, then panels, and finally all genes as encompassed by whole exome and genome sequencing. The intersection of these two technologies brings the revolutionary possibility of identifying all genetic disorders in newborns, allowing implementation of therapies at the optimum time regardless of symptoms. This article reviews the history of newborn screening and early studies examining the use of whole genome and exome sequencing as a screening tool. Lessons learned from these studies are discussed, along with technical, ethical, and societal challenges to broad implementation.

Bi-allelic GAD1 variants cause a neonatal onset syndromic developmental and epileptic encephalopathy

Developmental and epileptic encephalopathies are a heterogeneous group of early-onset epilepsy syndromes dramatically impairing neurodevelopment. Modern genomic technologies have revealed a number of monogenic origins and opened the door to therapeutic hopes. Here we describe a new syndromic developmental and epileptic encephalopathy caused by bi-allelic loss-of-function variants in GAD1, as presented by 11 patients from six independent consanguineous families. Seizure onset occurred in the first 2 months of life in all patients. All 10 patients, from whom early disease history was available, presented with seizure onset in the first month of life, mainly consisting of epileptic spasms or myoclonic seizures. Early EEG showed suppression-burst or pattern of burst attenuation or hypsarrhythmia if only recorded in the post-neonatal period. Eight patients had joint contractures and/or pes equinovarus. Seven patients presented a cleft palate and two also had an omphalocele, reproducing the phenotype of the knockout Gad1-/- mouse model. Four patients died before 4 years of age. GAD1 encodes the glutamate decarboxylase enzyme GAD67, a critical actor of the γ-aminobutyric acid (GABA) metabolism as it catalyses the decarboxylation of glutamic acid to form GABA. Our findings evoke a novel syndrome related to GAD67 deficiency, characterized by the unique association of developmental and epileptic encephalopathies, cleft palate, joint contractures and/or omphalocele.

Rapid acute care genomics: Challenges and opportunities for genetic counselors

Genomic medicine in pediatric acute care is showing great promise, with rapid results from exome and genome sequencing returned within days providing critically important information for treatment and management of seriously ill children. Many have suggested that rapid acute care genomics presents novel genetic counseling issues. This is due to the need for rapid response to referrals, the immense emotional distress that parents are likely to experience when their child is in acute care, and the unfamiliar environment of the acute care setting. To explore the practice of genetic counselors in this setting, we conducted qualitative interviews with 16 genetic counselors (GCs), representing a large proportion of GCs at the frontline of providing genetic counseling in acute care settings in Australia. Interviews revealed themes describing genetic counseling in acute care, including practical challenges of counseling within a rapid turnaround time, similarities with other contexts such as prenatal counseling, and the need for education of other health professionals. Interestingly, GCs did not raise concerns in the interviews for parents' ability to provide informed consent for rapid genomic sequencing. GCs also encountered practical and organizational challenges with counseling in this setting where 24-hr care is provided, at odds with traditional '9 to 5' Genetics service delivery. Working closely in a multidisciplinary team was common and participants believed that GCs are well positioned to take a leading role in the education of other health professionals as rapid acute care genomics becomes routine clinical practice. Despite views that genetic counseling practice in rapid acute care genomics is unique, these exploratory data suggest that GCs are flexible, adaptable, and sufficiently skilled to deliver patient-centered counseling in this setting. Our work indicates GCs are ready and willing to contribute at an early stage of adoption of genomic investigations in acute care.

An RCT of Rapid Genomic Sequencing among Seriously Ill Infants Results in High Clinical Utility, Changes in Management, and Low Perceived Harm

The second Newborn Sequencing in Genomic Medicine and Public Health (NSIGHT2) study was a randomized, controlled trial of rapid whole-genome sequencing (rWGS) or rapid whole-exome sequencing (rWES) in infants with diseases of unknown etiology in intensive care units (ICUs). Gravely ill infants were not randomized and received ultra-rapid whole-genome sequencing (urWGS). Herein we report results of clinician surveys of the clinical utility of rapid genomic sequencing (RGS). The primary end-point-clinician perception that RGS was useful- was met for 154 (77%) of 201 infants. Both positive and negative tests were rated as having clinical utility (42 of 45 [93%] and 112 of 156 [72%], respectively). Physicians reported that RGS changed clinical management in 57 (28%) infants, particularly in those receiving urWGS (p = 0.0001) and positive tests (p < 0.00001). Outcomes of 32 (15%) infants were perceived to be changed by RGS. Positive tests changed outcomes more frequently than negative tests (p < 0.00001). In logistic regression models, the likelihood that RGS was perceived as useful increased 6.7-fold when associated with changes in management (95% CI 1.8-43.3). Changes in management were 10.1-fold more likely when results were positive (95% CI 4.7-22.4) and turnaround time was shorter (odds ratio 0.92, 95% CI 0.85-0.99). RGS seldom led to clinician-perceived confusion or distress among families (6 of 207 [3%]). In summary, clinicians perceived high clinical utility and low likelihood of harm with first-tier RGS of infants in ICUs with diseases of unknown etiology. RGS was perceived as beneficial irrespective of whether results were positive or negative.

Rapid genome-wide sequencing in a neonatal intensive care unit: A retrospective qualitative exploration of parental experiences

Genome-wide sequencing (GWS) is increasingly being used in neonatal intensive care units. While studies have explored its clinical utility, little is known about parental experiences with this testing post-return of results. We conducted a qualitative study, using an interpretive description framework and thematic analysis, to gain further insight into parents' perceptions of the value and utility of GWS for their infant. We sought to explore whether parents' perceptions differ if their child received a diagnosis or not, and whether their child is living or deceased. Semi-structured, telephone interviews were conducted with parents of infants who had rapid exome sequencing while in the neonatal intensive care unit at BC Women's Hospital in Vancouver, Canada. Interviews addressed perceived benefits and harms of GWS and included an evaluation of decisional regret. Parents of 27 probands were approached and 14 (52%; 13 mothers and 1 father) participated in interviews. On average, 26 months had elapsed from the time of results to the interview. Six themes were identified. Firstly, parents had a positive regard for GWS. The results of GWS helped provide context for their child's admission to the NICU, and all parents experienced relief following receiving the results. A diagnosis by GWS enabled parents to picture the future, form connections with other parents, and coordinate their child's care. Lastly, some parents experienced discomfort with the concept of a genetic diagnosis, and interestingly felt lack of a genomic diagnosis indicated a reduced severity of their infant's condition. Decisional regret post-results was found to be low. Our results highlight how parents cope with the results of GWS and suggest that a genetic counselor can have an important role in helping families understand and adjust to these results in the neonatal intensive care unit.

The role of exome sequencing in newborn screening for inborn errors of metabolism

Public health newborn screening (NBS) programs provide population-scale ascertainment of rare, treatable conditions that require urgent intervention. Tandem mass spectrometry (MS/MS) is currently used to screen newborns for a panel of rare inborn errors of metabolism (IEMs)1-4. The NBSeq project evaluated whole-exome sequencing (WES) as an innovative methodology for NBS. We obtained archived residual dried blood spots and data for nearly all IEM cases from the 4.5 million infants born in California between mid-2005 and 2013 and from some infants who screened positive by MS/MS, but were unaffected upon follow-up testing. WES had an overall sensitivity of 88% and specificity of 98.4%, compared to 99.0% and 99.8%, respectively for MS/MS, although effectiveness varied among individual IEMs. Thus, WES alone was insufficiently sensitive or specific to be a primary screen for most NBS IEMs. However, as a secondary test for infants with abnormal MS/MS screens, WES could reduce false-positive results, facilitate timely case resolution and in some instances even suggest more appropriate or specific diagnosis than that initially obtained. This study represents the largest, to date, sequencing effort of an entire population of IEM-affected cases, allowing unbiased assessment of current capabilities of WES as a tool for population screening.

Rapid Phenotype-Driven Gene Sequencing with the NeoSeq Panel: A Diagnostic Tool for Critically Ill Newborns with Suspected Genetic Disease

New genomic sequencing techniques have shown considerable promise in the field of neonatology, increasing the diagnostic rate and reducing time to diagnosis. However, several obstacles have hindered the incorporation of this technology into routine clinical practice. We prospectively evaluated the diagnostic rate and diagnostic turnaround time achieved in newborns with suspected genetic diseases using a rapid phenotype-driven gene panel (NeoSeq) containing 1870 genes implicated in congenital malformations and neurological and metabolic disorders of early onset (<2 months of age). Of the 33 newborns recruited, a genomic diagnosis was established for 13 (39.4%) patients (median diagnostic turnaround time, 7.5 days), resulting in clinical management changes in 10 (76.9%) patients. An analysis of 12 previous prospective massive sequencing studies (whole genome (WGS), whole exome (WES), and clinical exome (CES) sequencing) in newborns admitted to neonatal intensive care units (NICUs) with suspected genetic disorders revealed a comparable median diagnostic rate (37.2%), but a higher median diagnostic turnaround time (22.3 days) than that obtained with NeoSeq. Our phenotype-driven gene panel, which is specific for genetic diseases in critically ill newborns is an affordable alternative to WGS and WES that offers comparable diagnostic efficacy, supporting its implementation as a first-tier genetic test in NICUs.

Feasibility of Ultra-Rapid Exome Sequencing in Critically Ill Infants and Children With Suspected Monogenic Conditions in the Australian Public Health Care System

IMPORTANCE

Widespread adoption of rapid genomic testing in pediatric critical care requires robust clinical and laboratory pathways that provide equitable and consistent service across health care systems.

OBJECTIVE

To prospectively evaluate the performance of a multicenter network for ultra-rapid genomic diagnosis in a public health care system.

DESIGN, SETTING, AND PARTICIPANTS

Descriptive feasibility study of critically ill pediatric patients with suspected monogenic conditions treated at 12 Australian hospitals between March 2018 and February 2019, with data collected to May 2019. A formal implementation strategy emphasizing communication and feedback, standardized processes, coordination, distributed leadership, and collective learning was used to facilitate adoption.

EXPOSURES

Ultra-rapid exome sequencing.

MAIN OUTCOMES AND MEASURES

The primary outcome was time from sample receipt to ultra-rapid exome sequencing report. The secondary outcomes were the molecular diagnostic yield, the change in clinical management after the ultra-rapid exome sequencing report, the time from hospital admission to the laboratory report, and the proportion of laboratory reports returned prior to death or hospital discharge.

RESULTS

The study population included 108 patients with a median age of 28 days (range, 0 days to 17 years); 34% were female; and 57% were from neonatal intensive care units, 33% were from pediatric intensive care units, and 9% were from other hospital wards. The mean time from sample receipt to ultra-rapid exome sequencing report was 3.3 days (95% CI, 3.2-3.5 days) and the median time was 3 days (range, 2-7 days). The mean time from hospital admission to ultra-rapid exome sequencing report was 17.5 days (95% CI, 14.6-21.1 days) and 93 reports (86%) were issued prior to death or hospital discharge. A molecular diagnosis was established in 55 patients (51%). Eleven diagnoses (20%) resulted from using the following approaches to augment standard exome sequencing analysis: mitochondrial genome sequencing analysis, exome sequencing-based copy number analysis, use of international databases to identify novel gene-disease associations, and additional phenotyping and RNA analysis. In 42 of 55 patients (76%) with a molecular diagnosis and 6 of 53 patients (11%) without a molecular diagnosis, the ultra-rapid exome sequencing result was considered as having influenced clinical management. Targeted treatments were initiated in 12 patients (11%), treatment was redirected toward palliative care in 14 patients (13%), and surveillance for specific complications was initiated in 19 patients (18%).

CONCLUSIONS AND RELEVANCE

This study suggests feasibility of ultra-rapid genomic testing in critically ill pediatric patients with suspected monogenic conditions in the Australian public health care system. However, further research is needed to understand the clinical value of such testing, and the generalizability of the findings to other health care settings.

Diagnosis of genetic diseases in seriously ill children by rapid whole-genome sequencing and automated phenotyping and interpretation

By informing timely targeted treatments, rapid whole-genome sequencing can improve the outcomes of seriously ill children with genetic diseases, particularly infants in neonatal and pediatric intensive care units (ICUs). The need for highly qualified professionals to decipher results, however, precludes widespread implementation. We describe a platform for population-scale, provisional diagnosis of genetic diseases with automated phenotyping and interpretation. Genome sequencing was expedited by bead-based genome library preparation directly from blood samples and sequencing of paired 100-nt reads in 15.5 hours. Clinical natural language processing (CNLP) automatically extracted children's deep phenomes from electronic health records with 80% precision and 93% recall. In 101 children with 105 genetic diseases, a mean of 4.3 CNLP-extracted phenotypic features matched the expected phenotypic features of those diseases, compared with a match of 0.9 phenotypic features used in manual interpretation. We automated provisional diagnosis by combining the ranking of the similarity of a patient's CNLP phenome with respect to the expected phenotypic features of all genetic diseases, together with the ranking of the pathogenicity of all of the patient's genomic variants. Automated, retrospective diagnoses concurred well with expert manual interpretation (97% recall and 99% precision in 95 children with 97 genetic diseases). Prospectively, our platform correctly diagnosed three of seven seriously ill ICU infants (100% precision and recall) with a mean time saving of 22:19 hours. In each case, the diagnosis affected treatment. Genome sequencing with automated phenotyping and interpretation in a median of 20:10 hours may increase adoption in ICUs and, thereby, timely implementation of precise treatments.

Exome sequencing compared with standard genetic tests for critically ill infants with suspected genetic conditions

PURPOSE

As exome sequencing (ES) is increasingly used as a diagnostic tool, we aimed to compare ES with status quo genetic diagnostic workup for infants with suspected genetic disorders in terms of identifying diagnoses, survival, and cost of care.

METHODS

We studied newborns and infants admitted to intensive care with a suspected genetic etiology within the first year of life at a US quaternary-referral children's hospital over 5 years. In this propensity-matched cohort study using electronic medical record data, we compared patients who received ES as part of a diagnostic workup (ES cohort, n = 368) with clinically similar patients who did not receive ES (No-ES cohort, n = 368).

RESULTS

Diagnostic yield (27.4% ES, 25.8% No-ES; p = 0.62) and 1-year survival (80.2% ES, 84.8% No-ES; p = 0.10) were no different between cohorts. ES cohort patients had higher cost of admission, diagnostic investigation, and genetic testing (all p < 0.01).

CONCLUSION

ES did not differ from status quo genetic testing collectively in terms of diagnostic yield or patient survival; however, it had high yield as a single test, led to complementary classes of diagnoses, and was associated with higher costs. Further work is needed to define the most efficient use of diagnostic ES for critically ill newborns and infants.

Clinical genomic testing: what matters to key stakeholders?

Beyond a narrow focus on cost and outcomes, robust evidence of what is valued in genomic medicine is scarce. We gathered views on value from key stakeholders (clinical genomic staff, operational genomic staff and community representatives) in relation to three testing contexts (General Healthcare, Acute Care and Neurodevelopmental Conditions). We conducted an iterative focus group in three stages over a week using a multiphase mixed methods study, i.e. quantitative ratings and qualitative discussion. For each testing context, the characteristics of genomic testing were generated and ranked by the group using a co-productive approach. Up to 17 characteristics were identified in one scenario with several characteristics featuring in all three testing contexts. The likelihood of getting an answer was consistently reported as most highly valued, followed by the potential for the test to impact on clinical management (or wellbeing/health for Neurodevelopmental Conditions). Risk of discrimination did not feature highly across the different settings (and not at all in Acute Care). While cost was an issue in the general health setting, it was one of the least-valued characteristics in the other two testing contexts. In conclusion, co-producing an understanding of what is valued in different testing contexts, and identifying the areas of differences or commonalities, is important to maximise value provision and inform future policy to ensure that clinical genomic services meet the needs of the community and service providers.

A brief history of human disease genetics

A primary goal of human genetics is to identify DNA sequence variants that influence biomedical traits, particularly those related to the onset and progression of human disease. Over the past 25 years, progress in realizing this objective has been transformed by advances in technology, foundational genomic resources and analytical tools, and by access to vast amounts of genotype and phenotype data. Genetic discoveries have substantially improved our understanding of the mechanisms responsible for many rare and common diseases and driven development of novel preventative and therapeutic strategies. Medical innovation will increasingly focus on delivering care tailored to individual patterns of genetic predisposition.

A Randomized, Controlled Trial of the Analytic and Diagnostic Performance of Singleton and Trio, Rapid Genome and Exome Sequencing in Ill Infants

The second Newborn Sequencing in Genomic Medicine and Public Health study was a randomized, controlled trial of the effectiveness of rapid whole-genome or -exome sequencing (rWGS or rWES, respectively) in seriously ill infants with diseases of unknown etiology. Here we report comparisons of analytic and diagnostic performance. Of 1,248 ill inpatient infants, 578 (46%) had diseases of unknown etiology. 213 infants (37% of those eligible) were enrolled within 96 h of admission. 24 infants (11%) were very ill and received ultra-rapid whole-genome sequencing (urWGS). The remaining infants were randomized, 95 to rWES and 94 to rWGS. The analytic performance of rWGS was superior to rWES, including variants likely to affect protein function, and ClinVar pathogenic/likely pathogenic variants (p < 0.0001). The diagnostic performance of rWGS and rWES were similar (18 diagnoses in 94 infants [19%] versus 19 diagnoses in 95 infants [20%], respectively), as was time to result (median 11.0 versus 11.2 days, respectively). However, the proportion diagnosed by urWGS (11 of 24 [46%]) was higher than rWES/rWGS (p = 0.004) and time to result was less (median 4.6 days, p < 0.0001). The incremental diagnostic yield of reflexing to trio after negative proband analysis was 0.7% (1 of 147). In conclusion, rapid genomic sequencing can be performed as a first-tier diagnostic test in inpatient infants. urWGS had the shortest time to result, which was important in unstable infants, and those in whom a genetic diagnosis was likely to impact immediate management. Further comparison of urWGS and rWES is warranted because genomic technologies and knowledge of variant pathogenicity are evolving rapidly.

Early diagnosis of Pearson syndrome in neonatal intensive care following rapid mitochondrial genome sequencing in tandem with exome sequencing

Rapid genomic testing is a valuable new diagnostic tool for acutely unwell infants, however exome sequencing does not deliver clinical-grade mitochondrial genome sequencing and may fail to diagnose mitochondrial disorders caused by mitochondrial DNA (mtDNA) variants. Rapid mitochondrial genome sequencing and analysis are not routinely available in rapid genomic diagnosis programmes. We present two critically ill neonates with transfusion-dependent anaemia and persistent lactic acidosis who underwent rapid mitochondrial genome sequencing in tandem with exome sequencing as part of an exome sequencing-based rapid genomic diagnosis programme. No diagnostic variants were identified on examination of the nuclear exome data for either infant. Mitochondrial genome sequencing identified a large mtDNA deletion in both infants, diagnosing Pearson syndrome within 74 and 55 h, respectively. Early diagnosis in the third week of life allowed the avoidance of a range of other investigations and appropriate treatment planning. Rapid mitochondrial genome analysis provides additional diagnostic and clinical utility and should be considered as an adjunct to exome sequencing in rapid genomic diagnosis programmes.

Attitudes of Australian health professionals towards rapid genomic testing in neonatal and paediatric intensive care

We investigated the attitudes of intensive care physicians and genetics professionals towards rapid genomic testing in neonatal and paediatric intensive care units (NICU/PICU). A mixed-methods study (surveys and interviews) was conducted at 13 Australian hospitals and three laboratories involved in multi-center implementation of rapid genomic testing. We investigated experience and confidence with genomic tests among intensivists; perceived usefulness of genomic diagnostic results; preferences for service delivery models; and implementation readiness among genetic services. The overall survey response rate was 59%, 47% for intensivists (80/170), and 75% (91/121) for genetics professionals. Intensivists reported moderate confidence with microarray tests and lower confidence with genomic tests. The majority of intensivists (77%), clinical geneticists (87%) and genetic counsellors (82%) favoured a clinical genetics-led service delivery model of genomic testing. Perceived clinical utility of genomic results was lower in the intensivist group compared to the genetics professionals group (20 v 50%, p < 0.001). Interviews (n = 6 intensivists; n = 11 genetic counselors) demonstrated support for implementation, with concerns relating to implementation environment and organizational readiness. Overall, our findings support initial implementation of genomic testing in NICU/PICU as part of an interdisciplinary service delivery model that promotes gradual adoption of genomics by the intensive care workforce while ensuring safety, sustainability, and efficiency.

Case for genome sequencing in infants and children with rare, undiagnosed or genetic diseases

Up to 350 million people worldwide suffer from a rare disease, and while the individual diseases are rare, in aggregate they represent a substantial challenge to global health systems. The majority of rare disorders are genetic in origin, with children under the age of five disproportionately affected. As these conditions are difficult to identify clinically, genetic and genomic testing have become the backbone of diagnostic testing in this population. In the last 10 years, next-generation sequencing technologies have enabled testing of multiple disease genes simultaneously, ranging from targeted gene panels to exome sequencing (ES) and genome sequencing (GS). GS is quickly becoming a practical first-tier test, as cost decreases and performance improves. A growing number of studies demonstrate that GS can detect an unparalleled range of pathogenic abnormalities in a single laboratory workflow. GS has the potential to deliver unbiased, rapid and accurate molecular diagnoses to patients across diverse clinical indications and complex presentations. In this paper, we discuss clinical indications for testing and historical testing paradigms. Evidence supporting GS as a diagnostic tool is supported by superior genomic coverage, types of pathogenic variants detected, simpler laboratory workflow enabling shorter turnaround times, diagnostic and reanalysis yield, and impact on healthcare.

Integrating Genomics into Healthcare: A Global Responsibility

Genomic sequencing is rapidly transitioning into clinical practice, and implementation into healthcare systems has been supported by substantial government investment, totaling over US$4 billion, in at least 14 countries. These national genomic-medicine initiatives are driving transformative change under real-life conditions while simultaneously addressing barriers to implementation and gathering evidence for wider adoption. We review the diversity of approaches and current progress made by national genomic-medicine initiatives in the UK, France, Australia, and US and provide a roadmap for sharing strategies, standards, and data internationally to accelerate implementation.

ClinGen advancing genomic data-sharing standards as a GA4GH driver project

The Clinical Genome Resource (ClinGen)'s work to develop a knowledge base to support the understanding of genes and variants for use in precision medicine and research depends on robust, broadly applicable, and adaptable technical standards for sharing data and information. To forward this goal, ClinGen has joined with the Global Alliance for Genomics and Health (GA4GH) to support the development of open, freely-available technical standards and regulatory frameworks for secure and responsible sharing of genomic and health-related data. In its capacity as one of the 15 inaugural GA4GH "Driver Projects," ClinGen is providing input on the key standards needs of the global genomics community, and has committed to participate on GA4GH Work Streams to support the development of: (1) a standard model for computer-readable variant representation; (2) a data model for linking variant data to annotations; (3) a specification to enable sharing of genomic variant knowledge and associated clinical interpretations; and (4) a set of best practices for use of phenotype and disease ontologies. ClinGen's participation as a GA4GH Driver Project will provide a robust environment to test drive emerging genomic knowledge sharing standards and prove their utility among the community, while accelerating the construction of the ClinGen evidence base.