Clinical Application of Genome and Exome Sequencing as a Diagnostic Tool for Pediatric Patients: a Scoping Review of the Literature

Learning to make a difference for chILD: Value creation through network collaboration and team science

Addressing the recognized challenges and inequalities in providing high quality healthcare for rare diseases such as children's interstitial lung disease (chILD) requires collaboration across institutional, geographical, discipline, and system boundaries. The Children's Interstitial Lung Disease Respiratory Network of Australia and New Zealand (chILDRANZ) is an example of a clinical network that brings together multidisciplinary health professionals for collaboration, peer learning, and advocacy with the goal of improving the diagnosis and management of this group of rare and ultra-rare conditions. This narrative review explores the multifaceted benefits arising from social learning spaces within rare disease clinical networks by applying the value creation framework. The operation of the chILDRANZ network is used as an example across the framework to highlight how value is generated, realized, and transferred within such collaborative clinical and research networks. The community of practice formed in the chILDRANZ multidisciplinary meetings provides a strong example of social learning that engages with the uncertainty inherent in rare disease diagnosis and management and pays attention to generate new knowledge and best practice to make a difference for children and families living with chILD. This review underscores international calls for further investment in, and support of, collaborative clinical networks and virtual centers of excellence for rare disease.

Measuring perceived utility of genomic sequencing: Development and validation of the GENEtic Utility (GENE-U) scale for pediatric diagnostic testing

PURPOSE

Measuring the effects of genomic sequencing (GS) on patients and families is critical for translational research. We aimed to develop and validate an instrument to assess parents' perceived utility of pediatric diagnostic GS.

METHODS

Informed by a 5-domain conceptual model, the study comprised 5 steps: (1) item writing, (2) cognitive testing, (3) pilot testing and item reduction, (4) psychometric testing, and (5) evaluation of construct validity. Parents of pediatric patients who had received results of clinically indicated GS participated in structured cognitive interviews and 2 rounds of surveys. After eliminating items based on theory and quantitative performance, we conducted an exploratory factor analysis and calculated Pearson correlations with related instruments.

RESULTS

We derived the 21-item Pediatric Diagnostic version of the GENEtic Utility (GENE-U) scale, which has a 2-factor structure that includes an Informational Utility subscale (16 items, α = 0.91) and an Emotional Utility subscale (5 items, α = 0.71). Scores can be summed to calculate a Total scale score (α = 0.87). The Informational Utility subscale was strongly associated with empowerment and personal utility of GS, and the Emotional Utility subscale was moderately associated with psychosocial impact and depression and anxiety.

CONCLUSION

The pediatric diagnostic GENE-U scale demonstrated good psychometric performance in this initial evaluation and could be a useful tool for translational genomics researchers, warranting additional validation.

Genome sequencing enables diagnosis and treatment of SLC5A6 neuropathy

The sodium-dependent multivitamin transporter encoded by SLC5A6 is responsible for uptake of biotin, pantothenic acid, and α-lipoic acid. Thirteen individuals from eight families are reported with pathogenic biallelic SLC5A6 variants. Phenotype ranges from multisystem metabolic disorder to childhood-onset peripheral motor neuropathy. We report three additional affected individuals with biallelic SLC5A6 variants. In Family A, a male proband (AII:1) presenting in early childhood with gross motor regression, motor axonal neuropathy, recurrent cytopenia and infections, and failure to thrive was diagnosed at 12 years of age via genome sequencing (GS) with a paternal NM_021095.4:c.393+2T>C variant and a maternal c.1285A>G p.(Ser429Gly) variant. An uncle with recurrent cytopenia and peripheral neuropathy was subsequently found to have the same genotype. We also report an unrelated female with peripheral neuropathy homozygous for the c.1285A>G p.(Ser429Gly) recurrent variant identified in seven reported cases, including this study. RT-PCR studies on blood mRNA from AII:1 showed c.393+2T>C caused mis-splicing with all canonically spliced transcripts in AII:1 containing the c.1285A>G variant. SLC5A6 mRNA expression in AII:1 fibroblasts was ~50% of control levels, indicative of nonsense-mediated decay of mis-spliced transcripts. Biotin uptake studies on AII:1 fibroblasts, expressing the p.(Ser429Gly) variant, showed an ~90% reduction in uptake compared to controls. Targeted treatment of AII:1 with biotin, pantothenic acid, and lipoic acid resulted in clinical improvement. Health Economic analyses showed implementation of GS as an early investigation could have saved $ AUD 105,988 and shortened diagnostic odyssey and initiation of treatment by up to 7 years.

Exome sequencing (ES) of a pediatric cohort with chronic endocrine diseases: a single-center study (within the framework of the TRANSLATE-NAMSE project)

BACKGROUND

Endocrine disorders are heterogeneous and include a significant number of rare monogenic diseases.

METHODS

We performed exome sequencing (ES) in 106 children recruited from a single center within the TRANSLATE‑NAMSE project. They were categorized into subgroups: proportionate short stature (PSS), disproportionate short stature (DSS), hypopituitarism (H), differences in sexual development (DSD), syndromic diseases (SD) and others.

RESULTS

The overall diagnostic yield was 34.9% (n = 37/106), including 5 patients with variants in candidate genes, which have contributed to collaborations to identify gene-disease associations. The diagnostic yield varied significantly between subgroups: PSS: 16.6% (1/6); DSS: 18.8% (3/16); H: 17.1% (6/35); DSD: 37.5% (3/8); SD: 66.6% (22/33); others: 25% (2/8). Confirmed diagnoses included 75% ultrarare diseases. Three patients harbored more than one disease-causing variant, resulting in dual diagnoses.

CONCLUSIONS

ES is an effective tool for genetic diagnosis in pediatric patients with complex endocrine diseases. An accurate phenotypic description, including comprehensive endocrine diagnostics, as well as the evaluation of variants in multidisciplinary case conferences involving geneticists, are necessary for personalized diagnostic care. Here, we illustrate the broad spectrum of genetic endocrinopathies that have led to the initiation of specific treatment, surveillance, and family counseling.

The utility of exome sequencing in diagnosing pediatric neurodevelopmental disorders in a highly consanguineous population

Exome sequencing (ES) has been utilized in diagnosing children with neurodevelopmental manifestations, this study aimed to investigate the utility of ES in children within a highly consanguineous population that presented with neurodevelopmental complaints. A retrospective chart review was performed for 405 children with neurodevelopmental complaints who have had ES and were evaluated in multiple centers in the United Arab Emirates over a four-year period. Within the cohort of 405 children, consanguinity was reported in 35% (144/405). The primary clinical presentations were developmental delay/cognitive impairment, distinctive facial features, hypotonia, seizures, and weakness. The diagnostic yield was 57% (231/405). Novel variants were identified in 54% (125/231) of positive cases. Within the positive cases, specific treatment was available in 6% (13/231) and copy number variants (CNV) were reported in 3% (8/231) of cases. In eight children, variants in genes that have not yet been linked to human disease that could potentially be the cause of the observed phenotype "candidate genes" were identified. ES was utilized effectively within this cohort with a high diagnostic yield and through the identification of novel gene variants, CNVs, candidate genes and secondary findings as well as the alteration of the treatment plan in cases where treatment was available.

Measuring health-related quality of life in children with suspected genetic conditions: validation of the PedsQL proxy-report versions

PURPOSE

Measuring health-related quality of life (HRQoL) of children with suspected genetic conditions is important for understanding the effect of interventions such as genomic sequencing (GS). The Pediatric Quality of Life Inventory (PedsQL) is a widely used generic measure of HRQoL in pediatric patients, but its psychometric properties have not yet been evaluated in children undergoing diagnostic GS.

METHODS

In this cross-sectional study, we surveyed caregivers at the time of their child's enrollment into GS research studies as part of the Clinical Sequencing Evidence Generating Research (CSER) consortium. To evaluate structural validity of the PedsQL 4.0 Generic Core Scales and PedsQL Infant Scales parent proxy-report versions, we performed a confirmatory factor analysis of the hypothesized factor structure. To evaluate convergent validity, we examined correlations between caregivers' reports of their child's health, assessed using the EQ VAS, and PedsQL scores by child age. We conducted linear regression analyses to examine whether age moderated the association between caregiver-reported child health and PedsQL scores. We assessed reliability using Cronbach's alpha.

RESULTS

We analyzed data for 766 patients across all PedsQL age group versions (1-12 months through 13-18 years). Model fit failed to meet criteria for good fit, even after modification. Neither age group (categorical) nor age (continuous) significantly moderated associations between PedsQL scores and caregiver-reported child health. Cronbach's alphas indicated satisfactory internal consistency for most PedsQL scales.

CONCLUSION

The PedsQL Generic Core Scales and Infant Scales may be appropriate to measure HRQoL in pediatric patients with suspected genetic conditions across a wide age range. While we found evidence of acceptable internal consistency and preliminary convergent validity in this sample, there were some potential problems with structural validity and reliability that require further attention.

Determining priority indicators of utility for genomic testing in rare disease: A Delphi study

PURPOSE

Determining the value of genomic tests in rare disease necessitates a broader conceptualization of genomic utility beyond diagnostic yield. Despite widespread discussion, consensus toward which aspects of value to consider is lacking. This study aimed to use expert opinion to identify and refine priority indicators of utility in rare disease genomic testing.

METHODS

We used 2 survey rounds following Delphi methodology to obtain consensus on indicators of utility among experts involved in policy, clinical, research, and consumer advocacy leadership in Australia. We analyzed quantitative and qualitative data to identify, define, and determine priority indicators.

RESULTS

Twenty-five experts completed round 1 and 18 completed both rounds. Twenty indicators reached consensus as a priority in value assessment, including those relating to prognostic information, timeliness of results, practical and health care outcomes, clinical accreditation, and diagnostic yield. Whereas indicators pertaining to discovery research, disutility, and factors secondary to primary reason for testing were considered less of a priority and were removed.

CONCLUSION

This study obtained expert consensus on different utility indicators that are considered a priority in determining the value of genomic testing in rare disease in Australia. Indicators may inform a standardized approach to evidence generation and assessment to guide future research, decision making, and implementation efforts.

Reanalysis of genomic data, how do we do it now and what if we automate it? A qualitative study

Automating reanalysis of genomic data for undiagnosed rare disease patients presents a paradigm shift in how clinical genomics is delivered. We aimed to map the current manual and proposed automated approach to reanalysis and identify possible implementation strategies to address clinical and laboratory staff's perceived challenges to automation. Fourteen semi-structured interviews guided by a simplified process map were conducted with clinical and laboratory staff across Australia. Individual process maps were integrated into an overview of the current process, noting variation in service delivery. Participants then mapped an automated approach and were invited to discuss perceived challenges and possible supports to automation. Responses were analysed using the Consolidated Framework for Implementation Research, linking to the Expert Recommendations for Implementing Change framework to identify theory-informed implementation strategies. Process mapping demonstrates how automation streamlines processes with eleven steps reduced to seven. Although participants welcomed automation, challenges were raised at six of the steps. Strategies to overcome challenges include embedding project champions, developing education materials, facilitating clinical innovation and quality monitoring tools, and altering reimbursement structures. Future work can build on these findings to develop context specific implementation strategies to guide translation of an automated approach to reanalysis to improve clinical care and patient outcomes.

Role of next generation sequencing in diagnosis and management of critically ill children with suspected monogenic disorder

Next generation sequencing based diagnosis has emerged as a promising tool for evaluating critically ill neonates and children. However, there is limited data on its utility in developing countries. We assessed its diagnostic rate and clinical impact on management of pediatric patients with a suspected genetic disorder requiring critical care. The study was conducted at a single tertiary hospital in Northern India. We analyzed 70 children with an illness requiring intensive care and obtained a precise molecular diagnosis in 32 of 70 probands (45.3%) using diverse sequencing techniques such as clinical exome, whole exome, and whole genome. A significant change in clinical outcome was observed in 13 of 32 (40.6%) diagnosed probands with a change in medication in 11 subjects and redirection to palliative care in two subjects. Additional benefits included specific dietary management (three cases), avoidance of a major procedure (one case) and better reproductive counseling. Dramatic therapeutic responses were observed in three cases with SCN1A, SCN2A and KCNQ2-related epileptic encephalopathy. A delayed turn-around for sequencing results was perceived as a major limiting factor in the study, as rapid and ultra-rapid sequencing was not available. Achieving a precise molecular diagnosis has great utility in managing critically ill patients with suspected genetic disorders in developing countries.

Evidence review and considerations for use of first line genome sequencing to diagnose rare genetic disorders

Early use of genome sequencing (GS) in the diagnostic odyssey can reduce suffering and improve care, but questions remain about which patient populations are most amenable to GS as a first-line diagnostic test. To address this, the Medical Genome Initiative conducted a literature review to identify appropriate clinical indications for GS. Studies published from January 2011 to August 2022 that reported on the diagnostic yield (DY) or clinical utility of GS were included. An exploratory meta-analysis using a random effects model evaluated DY based on cohort size and diagnosed cases per cohort. Seventy-one studies met inclusion criteria, comprising over 13,000 patients who received GS in one of the following settings: hospitalized pediatric patients, pediatric outpatients, adult outpatients, or mixed. GS was the first-line test in 38% (27/71). The unweighted mean DY of first-line GS was 45% (12-73%), 33% (6-86%) in cohorts with prior genetic testing, and 33% (9-60%) in exome-negative cohorts. Clinical utility was reported in 81% of first-line GS studies in hospitalized pediatric patients. Changes in management varied by cohort and underlying molecular diagnosis (24-100%). To develop evidence-informed points to consider, the quality of all 71 studies was assessed using modified American College of Radiology (ACR) criteria, with five core points to consider developed, including recommendations for use of GS in the N/PICU, in lieu of sequential testing and when disorders with substantial allelic heterogeneity are suspected. Future large and controlled studies in the pediatric and adult populations may support further refinement of these recommendations.

Physician services and costs after disclosure of diagnostic sequencing results in the NYCKidSeq program

PURPOSE

To better understand the effects of returning diagnostic sequencing results on clinical actions and economic outcomes for pediatric patients with suspected genetic disorders.

METHODS

Longitudinal physician claims data after diagnostic sequencing were obtained for patients aged 0 to 21 years with neurologic, cardiac, and immunologic disorders with suspected genetic etiology. We assessed specialist consultation rates prompted by primary diagnostic results, as well as marginal effects on overall 18-month physician services and costs.

RESULTS

We included data on 857 patients (median age: 9.6 years) with a median follow-up of 17.3 months after disclosure of diagnostic sequencing results. The likelihood of having ≥1 recommendation for specialist consultation in 155 patients with positive findings was high (72%) vs 23% in 443 patients with uncertain findings and 21% in 259 patients with negative findings (P < .001). Follow-through consultation occurred in 30%. Increases in 18-month physician services and costs following a positive finding diminished after multivariable adjustment. Also, no significant differences between those with uncertain and negative findings were demonstrated.

CONCLUSION

Our study did not provide evidence for significant increases in downstream physician services and costs after returning positive or uncertain diagnostic sequencing findings. More large-scale longitudinal studies are needed to confirm these findings.

The best of both worlds: Blending cutting-edge research with clinical processes for a productive exome clinic

Genomic medicine has been transformed by next-generation sequencing (NGS), inclusive of exome sequencing (ES) and genome sequencing (GS). Currently, ES is offered widely in clinical settings, with a less prevalent alternative model consisting of hybrid programs that incorporate research ES along with clinical patient workflows. We were among the earliest to implement a hybrid ES clinic, have provided diagnoses to 45% of probands, and have identified several novel candidate genes. Our program is enabled by a cost-effective investment by the health system and is unique in encompassing all the processes that have been variably included in other hybrid/clinical programs. These include careful patient selection, utilization of a phenotype-agnostic bioinformatics pipeline followed by manual curation of variants and phenotype integration by clinicians, close collaborations between the clinicians and the bioinformatician, pursuit of interesting variants, communication of results to patients in categories that are predicated upon the certainty of a diagnosis, and tracking changes in results over time and the underlying mechanisms for such changes. Due to its effectiveness, scalability to GS and its resource efficiency, specific elements of our paradigm can be incorporated into existing clinical settings, or the entire hybrid model can be implemented within health systems that have genomic medicine programs, to provide NGS in a scientifically rigorous, yet pragmatic setting.

Inherited ichthyosis as a paradigm of rare skin disorders: Genomic medicine, pathogenesis, and management

Great advances have been made in the field of heritable skin disorders using next-generation sequencing (NGS) technologies (ie, whole-genome sequencing, whole-exome sequencing, whole-transcriptome sequencing, and disease-targeted multigene panels). When NGS first became available, the cost and lack of access to these technologies were limiting factors; however, with decreasing sequencing costs and the expanding knowledge base of genetic skin diseases, fundamental awareness of NGS has become prudent. The heritable ichthyoses comprise a genotypically and phenotypically heterogeneous group of monogenic keratinization disorders characterized by persistent scaling, with at least 55 distinct genes currently implicated in causing nonsyndromic and syndromic forms of the disease. By providing a simplified overview of available NGS techniques and applying them in the context of ichthyosis, one of the most common genodermatoses, we hope to encourage dermatologists to offer, when appropriate, genetic testing earlier in patients with unsolved presentations. With the aid of NGS, dermatologists can provide diagnostic certainty in cases of suspected genodermatoses and offer potentially life-changing genome-guided and targeted therapies as they become available.

The Diagnostic Landscape of Adult Neurogenetic Disorders

Neurogenetic diseases affect individuals across the lifespan, but accurate diagnosis remains elusive for many patients. Adults with neurogenetic disorders often undergo a long diagnostic odyssey, with multiple specialist evaluations and countless investigations without a satisfactory diagnostic outcome. Reasons for these diagnostic challenges include: (1) clinical features of neurogenetic syndromes are diverse and under-recognized, particularly those of adult-onset, (2) neurogenetic syndromes may manifest with symptoms that span multiple neurological and medical subspecialties, and (3) a positive family history may not be present or readily apparent. Furthermore, there is a large gap in the understanding of how to apply genetic diagnostic tools in adult patients, as most of the published literature focuses on the pediatric population. Despite these challenges, accurate genetic diagnosis is imperative to provide affected individuals and their families guidance on prognosis, recurrence risk, and, for an increasing number of disorders, offer targeted treatment. Here, we provide a framework for recognizing adult neurogenetic syndromes, describe the current diagnostic approach, and highlight studies using next-generation sequencing in different neurological disease cohorts. We also discuss diagnostic pitfalls, barriers to achieving a definitive diagnosis, and emerging technology that may increase the diagnostic yield of testing.

Prospect of genetic disorders in Saudi Arabia

Introduction: Rare diseases (RDs) create a massive burden for governments and families because sufferers of these diseases are required to undergo long-term treatment or rehabilitation to maintain a normal life. In Saudi Arabia (SA), the prevalence of RDs is high as a result of cultural and socio-economic factors. This study, however, aims to shed light on the genetic component of the prevalence of RDs in SA. Methodology: A retrospective study was conducted between September 2020 and December 2021 at King Saud Medical City, a tertiary hospital of the Ministry of Health (MOH), SA. A total of 1080 individuals with 544 potentially relevant variants were included. The index was 738, and the samples were tested in a commercialized laboratory using different molecular techniques, including next-generation sequencing. Result: A total of 867 molecular genetics tests were conducted on 738 probands. These tests included 610 exome sequencing (ES) tests, four genome sequencing (GS) tests, 82 molecular panels, 106 single nucleotide polymorphism (SNP) array, four methylation studies, 58 single-gene studies and three mitochondrial genome sequencing tests. The diagnostic yield among molecular genetics studies was 41.8% in ES, 24% in panels, 12% in SNP array and 24% in single gene studies. The majority of the identified potential variants (68%) were single nucleotide variants (SNV). Other ascertained variants included frameshift (11%), deletion (10%), duplication (5%), splicing (9%), in-frame deletion (3%) and indels (1%). The rate of positive consanguinity was 56%, and the autosomal recessive accounted for 54%. We found a significant correlation between the ES detection rate and positive consanguinity. We illustrated the presence of rare treatable conditions in DNAJC12, SLC19A3, and ALDH7A1, and the presence of the founder effect variant in SKIC2. Neurodevelopmental disorders were the main phenotype for which genetics studies were required (35.7%). Conclusion: This is the sixth-largest local study reporting next-generation sequencing. The results indicate the influence of consanguineous marriages on genetic disease and the burden it causes for the Kingdom of SA. This study highlights the need to enrich our society's knowledge of genetic disorders. We recommend utilising ES as a first-tier test to establish genetic diagnosis in a highly consanguineous population.

Molecular diagnostic yield of genome sequencing versus targeted gene panel testing in racially and ethnically diverse pediatric patients

PURPOSE

Adoption of genome sequencing (GS) as a first-line test requires evaluation of its diagnostic yield. We evaluated the GS and targeted gene panel (TGP) testing in diverse pediatric patients (probands) with suspected genetic conditions.

METHODS

Probands with neurologic, cardiac, or immunologic conditions were offered GS and TGP testing. Diagnostic yield was compared using a fully paired study design.

RESULTS

A total of 645 probands (median age 9 years) underwent genetic testing, and 113 (17.5%) received a molecular diagnosis. Among 642 probands with both GS and TGP testing, GS yielded 106 (16.5%) and TGPs yielded 52 (8.1%) diagnoses (P < .001). Yield was greater for GS vs TGPs in Hispanic/Latino(a) (17.2% vs 9.5%, P < .001) and White/European American (19.8% vs 7.9%, P < .001) but not in Black/African American (11.5% vs 7.7%, P = .22) population groups by self-report. A higher rate of inconclusive results was seen in the Black/African American (63.8%) vs White/European American (47.6%; P = .01) population group. Most causal copy number variants (17 of 19) and mosaic variants (6 of 8) were detected only by GS.

CONCLUSION

GS may yield up to twice as many diagnoses in pediatric patients compared with TGP testing but not yet across all population groups.

Exome Sequencing Expands the Genetic Diagnostic Spectrum for Pediatric Hearing Loss

OBJECTIVES

Genetic testing is the standard-of-care for diagnostic evaluation of bilateral, symmetric, sensorineural hearing loss (HL). We sought to determine the efficacy of a comprehensive genetic testing method, exome sequencing (ES), in a heterogeneous pediatric patient population with bilateral symmetric, bilateral asymmetric, and unilateral HL.

METHODS

Trio-based ES was performed for pediatric patients with confirmed HL including those with symmetric, asymmetric, and unilateral HL.

RESULTS

ES was completed for 218 probands. A genetic cause was identified for 31.2% of probands (n = 68). The diagnostic rate was 40.7% for bilateral HL, 23.1% for asymmetric HL, and 18.3% for unilateral HL, with syndromic diagnoses made in 20.8%, 33.3%, and 54.5% of cases in each group, respectively. Secondary or incidental findings were identified in 10 families (5.52%).

CONCLUSION

ES is an effective method for genetic diagnosis for HL including phenotypically diverse patients and allows the identification of secondary findings, discovery of deafness-causing genes, and the potential for efficient data re-analysis.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2417-2424, 2023.

At-Risk Genomic Findings for Pediatric-Onset Disorders From Genome Sequencing vs Medically Actionable Gene Panel in Proactive Screening of Newborns and Children

Importance

Although the clinical utility of genome sequencing for critically ill children is well recognized, its utility for proactive pediatric screening is not well explored.

Objective

To evaluate molecular findings from screening ostensibly healthy children with genome sequencing compared with a gene panel for medically actionable pediatric conditions.

Design, Setting, and Participants

This case series study was conducted among consecutive, apparently healthy children undergoing proactive genetic screening for pediatric disorders by genome sequencing (n = 562) or an exome-based panel of 268 genes (n = 606) from March 1, 2018, through July 31, 2022.

Exposures

Genetic screening for pediatric-onset disorders using genome sequencing or an exome-based panel of 268 genes.

Main Outcomes and Measures

Molecular findings indicative of genetic disease risk.

Results

Of 562 apparently healthy children (286 girls [50.9%]; median age, 29 days [IQR, 9-117 days]) undergoing screening by genome sequencing, 46 (8.2%; 95% CI, 5.9%-10.5%) were found to be at risk for pediatric-onset disease, including 22 children (3.9%) at risk for high-penetrance disorders. Sequence analysis uncovered molecular diagnoses among 32 individuals (5.7%), while copy number variant analysis uncovered molecular diagnoses among 14 individuals (2.5%), including 4 individuals (0.7%) with chromosome scale abnormalities. Overall, there were 47 molecular diagnoses, with 1 individual receiving 2 diagnoses; of the 47 potential diagnoses, 22 (46.8%) were associated with high-penetrance conditions. Pathogenic variants in medically actionable pediatric genes were found in 6 individuals (1.1%), constituting 12.8% (6 of 47) of all diagnoses. At least 1 pharmacogenomic variant was reported for 89.0% (500 of 562) of the cohort. In contrast, of 606 children (293 girls [48.3%]; median age, 26 days [IQR, 10-67 days]) undergoing gene panel screening, only 13 (2.1%; 95% CI, 1.0%-3.3%) resulted in potential childhood-onset diagnoses, a significantly lower rate than those screened by genome sequencing (P < .001).

Conclusions and Relevance

In this case series study, genome sequencing as a proactive screening approach for children, due to its unrestrictive gene content and technical advantages in comparison with an exome-based gene panel for medically actionable childhood conditions, uncovered a wide range of heterogeneous high-penetrance pediatric conditions that could guide early interventions and medical management.

Var∣Decrypt: a novel and user-friendly tool to explore and prioritize variants in whole-exome sequencing data

BACKGROUND

High-throughput sequencing (HTS) offers unprecedented opportunities for the discovery of causative gene variants in multiple human disorders including cancers, and has revolutionized clinical diagnostics. However, despite more than a decade of use of HTS-based assays, extracting relevant functional information from whole-exome sequencing (WES) data remains challenging, especially for non-specialists lacking in-depth bioinformatic skills.

RESULTS

To address this limitation, we developed Var∣Decrypt, a web-based tool designed to greatly facilitate WES data browsing and analysis. Var∣Decrypt offers a wide range of gene and variant filtering possibilities, clustering and enrichment tools, providing an efficient way to derive patient-specific functional information and to prioritize gene variants for functional analyses. We applied Var∣Decrypt on WES datasets of 10 acute erythroid leukemia patients, a rare and aggressive form of leukemia, and recovered known disease oncogenes in addition to novel putative drivers. We additionally validated the performance of Var∣Decrypt using an independent dataset of ~ 90 multiple myeloma WES, recapitulating the identified deregulated genes and pathways, showing the general applicability and versatility of Var∣Decrypt for WES analysis.

CONCLUSION

Despite years of use of WES in human health for diagnosis and discovery of disease drivers, WES data analysis still remains a complex task requiring advanced bioinformatic skills. In that context, there is a need for user-friendly all-in-one dedicated tools for data analysis, to allow biologists and clinicians to extract relevant biological information from patient datasets. Here, we provide Var∣Decrypt (trial version accessible here: https://vardecrypt.com/app/vardecrypt ), a simple and intuitive Rshiny application created to fill this gap. Source code and detailed user tutorial are available at https://gitlab.com/mohammadsalma/vardecrypt .

Diagnostic yield of pediatric and prenatal exome sequencing in a diverse population

The diagnostic yield of exome sequencing (ES) has primarily been evaluated in individuals of European ancestry, with less focus on underrepresented minority (URM) and underserved (US) patients. We evaluated the diagnostic yield of ES in a cohort of predominantly US and URM pediatric and prenatal patients suspected to have a genetic disorder. Eligible pediatric patients had multiple congenital anomalies and/or neurocognitive disabilities and prenatal patients had one or more structural anomalies, disorders of fetal growth, or fetal effusions. URM and US patients were prioritized for enrollment and underwent ES at a single academic center. We identified definitive positive or probable positive results in 201/845 (23.8%) patients, with a significantly higher diagnostic rate in pediatric (26.7%) compared to prenatal patients (19.0%) (P = 0.01). For both pediatric and prenatal patients, the diagnostic yield and frequency of inconclusive findings did not differ significantly between URM and non-URM patients or between patients with US status and those without US status. Our results demonstrate a similar diagnostic yield of ES between prenatal and pediatric URM/US patients and non-URM/US patients for positive and inconclusive results. These data support the use of ES to identify clinically relevant variants in patients from diverse populations.

Phenotypic specificity in patients with neurodevelopmental delay does not correlate with diagnostic yield of trio-exome sequencing

In this study, we aimed to examine the diagnostic yield achieved by applying a trio approach in exome sequencing (ES) and the interdependency between the clinical specificity in families with neurodevelopmental delay. Thirty-seven families were recruited and trio-ES as well as three criteria for estimating the clinical phenotypic specificity were suggested and applied to the underaged children. All our patients showed neurodevelopmental delay and most of them a large spectrum of congenital anomalies. Applying the pathogenicity guidelines of the American College of Medical Genetics (ACMG), likely pathogenic (29.7%) and pathogenic variants (8.1%) were found in 40,5% of our index patients. Additionally, we found four variants of uncertain significance (VUS; according to ACMG) and two genes of interest (GOI; going beyond ACMG classification) (GLRA4, NRXN2). Spastic Paraplegia 4 (SPG4) caused by a formerly known SPAST variant was diagnosed in a patient with a complex phenotype, in whom a second genetic disorder may be present. A potential pathogenic variant linked to severe intellectual disability in GLRA4 requires further investigation. No interdependency between the diagnostic yield and the clinical specificity of the phenotypes could be observed. In consequence, trio-ES should be used early in the diagnostic process, independently from the specificity of the patient.

Framing the Family: A Qualitative Exploration of Factors That Shape Family-Level Experience of Pediatric Genomic Sequencing

Families of children with rare and undiagnosed conditions face many psychosocial and logistical challenges that may affect their approach to decisions about their child's care and their family's well-being. As genomic sequencing (GS) is increasingly incorporated into pediatric diagnostic workups, assessing the family-level characteristics that shape the experience of pediatric GS is crucial to understanding how families approach decision-making about the test and how they incorporate the results into their family life. We conducted semi-structured interviews with parents and other primary caregivers of pediatric patients who were evaluated for a suspected genetic condition and who were recommended to have GS (n = 20) or who had recently completed GS (n = 21). We analyzed qualitative data using multiple rounds of thematic analysis. We organized our thematic findings into three domains of factors that influence the family-level experience of GS: (1) family structure and dynamics; (2) parental identity, relationships, and philosophies; and (3) social and cultural differences. Participants conceptualized their child's family in various ways, ranging from nuclear biological family to support networks made up of friends and communities. Our findings can inform the design and interpretation of preference research to advance family-level value assessment of GS as well as genetic counseling for families.

Rapid exome sequencing as a first-tier test in neonates with suspected genetic disorder: results of a prospective multicenter clinical utility study in the Netherlands

The introduction of rapid exome sequencing (rES) for critically ill neonates admitted to the neonatal intensive care unit has made it possible to impact clinical decision-making. Unbiased prospective studies to quantify the impact of rES over routine genetic testing are, however, scarce. We performed a clinical utility study to compare rES to conventional genetic diagnostic workup for critically ill neonates with suspected genetic disorders. In a multicenter prospective parallel cohort study involving five Dutch NICUs, we performed rES in parallel to routine genetic testing for 60 neonates with a suspected genetic disorder and monitored diagnostic yield and the time to diagnosis. To assess the economic impact of rES, healthcare resource use was collected for all neonates. rES detected more conclusive genetic diagnoses than routine genetic testing (20% vs. 10%, respectively), in a significantly shorter time to diagnosis (15 days (95% CI 10-20) vs. 59 days (95% CI 23-98, p < 0.001)). Moreover, rES reduced genetic diagnostic costs by 1.5% (€85 per neonate).

CONCLUSION

 Our findings demonstrate the clinical utility of rES for critically ill neonates based on increased diagnostic yield, shorter time to diagnosis, and net healthcare savings. Our observations warrant the widespread implementation of rES as first-tier genetic test in critically ill neonates with disorders of suspected genetic origin.

WHAT IS KNOWN

• Rapid exome sequencing (rES) enables diagnosing rare genetic disorders in a fast and reliable manner, but retrospective studies with neonates admitted to the neonatal intensive care unit (NICU) indicated that genetic disorders are likely underdiagnosed as rES is not routinely used. • Scenario modeling for implementation of rES for neonates with presumed genetic disorders indicated an expected increase in costs associated with genetic testing.

WHAT IS NEW

• This unique prospective national clinical utility study of rES in a NICU setting shows that rES obtained more and faster diagnoses than conventional genetic tests. • Implementation of rES as replacement for all other genetic tests does not increase healthcare costs but in fact leads to a reduction in healthcare costs.

Molecular diagnostic yield of genome sequencing versus targeted gene panel testing in racially and ethnically diverse pediatric patients

Purpose

Adoption of genome sequencing (GS) as a first-line test requires evaluation of its diagnostic yield. We evaluated the GS and targeted gene panel (TGP) testing in diverse pediatric patients (probands) with suspected genetic conditions.

Methods

Probands with neurologic, cardiac, or immunologic conditions were offered GS and TGP testing. Diagnostic yield was compared using a fully paired study design.

Results

645 probands (median age 9 years) underwent genetic testing, and 113 (17.5%) received a molecular diagnosis. Among 642 probands with both GS and TGP testing, GS yielded 106 (16.5%) and TGPs yielded 52 (8.1%) diagnoses ( P < .001). Yield was greater for GS vs . TGPs in Hispanic/Latino(a) (17.2% vs . 9.5%, P < .001) and White/European American (19.8% vs . 7.9%, P < .001), but not in Black/African American (11.5% vs . 7.7%, P = .22) population groups by self-report. A higher rate of inconclusive results was seen in the Black/African American (63.8%) vs . White/European American (47.6%; P = .01) population group. Most causal copy number variants (17 of 19) and mosaic variants (6 of 8) were detected only by GS.

Conclusion

GS may yield up to twice as many diagnoses in pediatric patients compared to TGP testing, but not yet across all population groups.

Outcomes of Returning Medically Actionable Genomic Results in Pediatric Research

Purpose: The electronic Medical Records and Genomics (eMERGE) Phase III study was undertaken to assess clinical utility of returning medically actionable genomic screening results. We assessed pediatric clinical outcomes following return of pathogenic/likely pathogenic (P/LP) variants in autosomal dominant conditions with available effective interventions. Methods: The two eMERGE III pediatric sites collected outcome data and assessed changes in medical management at 6 and 12 months. Results: We returned P/LP results to 29 participants with outcome data. For 23 of the 29 participants, the P/LP results were previously unknown. Five of the 23 participants were already followed for conditions related to the P/LP variant. Of those receiving novel results and not being followed for the condition related to the P/LP result (n = 18), 14 (77.8%) had a change in healthcare after return of results (RoR). Following RoR, cascade testing of family members occurred for 10 of 23 (43.5%). Conclusions: The most common outcomes post-RoR included imaging/laboratory testing and health behavior recommendations. A change in healthcare was documented in 77.8% of those receiving results by 6 months. Our findings demonstrate how return of genomic screening results impacts healthcare in pediatric populations.

Positioning whole exome sequencing in the diagnostic pathway for rare disease to optimise utility: a protocol for an observational cohort study and an economic evaluation

INTRODUCTION

Despite the superior diagnostic performance of exome and genome sequencing compared with conventional genetic tests, evidence gaps related to clinical utility and cost effectiveness have limited their availability in routine clinical practice in many jurisdictions. To inform adoption and reimbursement policy, this protocol provides a chain of evidence approach to determining the diagnostic utility, clinical utility and cost-effectiveness of whole exome sequencing (WES) from seven medical genetic centres in two Canadian provinces.

METHODS AND ANALYSIS

Using a multicentre observational cohort design, we will extract data specific to the pre-WES diagnostic pathway and 1-year post-WES medical management from electronic medical records for 650 patients with rare disease of suspected genetic aetiology who receive WES. The date from the clinical record will be linked to provincial administrative health database to capture healthcare resource use and estimate costs. Our analysis will: (1) define and describe diagnostic testing pathways that occur prior to WES among patients with rare disease, (2) determine the diagnostic utility of WES, characterised as the proportion of patients for whom causative DNA variants are identified, (3) determine the clinical utility of WES, characterised as a change in medical management triggered by WES results, (4) determine the pattern and cost of health service utilisation prior and 1 year following WES among patients who receive a diagnosis, do not receive a diagnosis, or receive an uncertain diagnosis and (5) estimate the cost-effectiveness of WES compared with conventional diagnostic testing pathways, measured by the incremental cost per additional patient diagnosed by WES using simulation modelling.

ETHICS AND DISSEMINATION

This protocol was approved by Clinical Trials Ontario (CTO-1577) and research ethics boards at the University of Calgary (REB18-0744 and REB20-1449) and University of Alberta (Pro0009156). Findings will be disseminated through academic publications and policy reports.

Cost-effectiveness frameworks for comparing genome and exome sequencing versus conventional diagnostic pathways: A scoping review and recommended methods

PURPOSE

Methodological challenges have limited economic evaluations of genome sequencing (GS) and exome sequencing (ES). Our objective was to develop conceptual frameworks for model-based cost-effectiveness analyses (CEAs) of diagnostic GS/ES.

METHODS

We conducted a scoping review of economic analyses to develop and iterate with experts a set of conceptual CEA frameworks for GS/ES for prenatal testing, early diagnosis in pediatrics, diagnosis of delayed-onset disorders in pediatrics, genetic testing in cancer, screening of newborns, and general population screening.

RESULTS

Reflecting on 57 studies meeting inclusion criteria, we recommend the following considerations for each clinical scenario. For prenatal testing, performing comparative analyses of costs of ES strategies and postpartum care, as well as genetic diagnoses and pregnancy outcomes. For early diagnosis in pediatrics, modeling quality-adjusted life years (QALYs) and costs over ≥20 years for rapid turnaround GS/ES. For hereditary cancer syndrome testing, modeling cumulative costs and QALYs for the individual tested and first/second/third-degree relatives. For tumor profiling, not restricting to treatment uptake or response and including QALYs and costs of downstream outcomes. For screening, modeling lifetime costs and QALYs and considering consequences of low penetrance and GS/ES reanalysis.

CONCLUSION

Our frameworks can guide the design of model-based CEAs and ultimately foster robust evidence for the economic value of GS/ES.

Continuing the sequence? Towards an economic evaluation of whole genome sequencing for the diagnosis of rare diseases in Scotland

Novel developments in genomic medicine may reduce the length of the diagnostic odyssey for patients with rare diseases. Health providers must thus decide whether to offer genome sequencing for the diagnosis of rare conditions in a routine clinical setting. We estimated the costs of singleton standard genetic testing and trio-based whole genome sequencing (WGS), in the context of the Scottish Genomes Partnership (SGP) study. We also explored what users value about genomic sequencing. Insights from the costing and value assessments will inform a subsequent economic evaluation of genomic medicine in Scotland. An average cost of £1,841 per singleton was estimated for the standard genetic testing pathway, with significant variability between phenotypes. WGS cost £6625 per family trio, but this estimate reflects the use of WGS during the SGP project and large cost savings may be realised if sequencing was scaled up. Patients and families valued (i) the chance of receiving a diagnosis (and the peace of mind and closure that brings); (ii) the information provided by WGS (including implications for family planning and secondary findings); and (iii) contributions to future research. Our costings will be updated to address limitations of the current study for incorporation in budget impact modelling and cost-effectiveness analysis (cost per diagnostic yield). Our insights into the benefits of WGS will guide the development of a discrete choice experiment valuation study. This will inform a user-perspective cost-benefit analysis of genome-wide sequencing, accounting for the broader non-health outcomes. Taken together, our research will inform the long-term strategic development of NHS Scotland clinical genetics testing services, and will be of benefit to others seeking to undertake similar evaluations in different contexts.

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.

The Interdisciplinary Diagnosis of Rare Diseases

BACKGROUND

Patients with rare diseases often undergo a diagnostic odyssey that can last many years until the diagnosis is definitively established. To improve the diagnosis and treatment of these patients, the German National Task Force for Patients With Rare Diseases (Nationales Aktionsbündnis für Menschen mit Seltenen Erkrankungen, NAMSE) has recommended the creation of Rare Disease Centers (RDCs).

METHODS

As part of the joint Translate-NAMSE project, sponsored by the G-BA Innovation Fund (G-BA, German Federal Joint Committee), we investigated the performance of RDCs in establishing the diagnosis of patients suspected to have a rare disease. The results of interdisciplinary case conferences and of exome diagnostic tests were analyzed in a prospective, multicenter observational study.

RESULTS

A total of 5652 patients (of whom 3619 were under 18 years old, and 2033 were at least 18 years old) from 10 RDCs who did not yet have a definitive diagnosis of a rare disease were included in the study. On average, those who were under 18 years old had been symptomatic for 4.5 years without receiving a diagnosis in a standard care setting; the analogous figure for adult patients was 8.2 years. Over the course of this project (2017-2021), 1682 patients (30%) received a definitive diagnosis. 193 had a common disease, 88 had a psychosomatic disease (only in patients who were at least 18 years old), and 1401 had a rare disease. 14 850 case conferences were conducted. 1599 exome analyses led to 506 definitive genetic diagnoses (32%).

CONCLUSION

A diagnostic evaluation with the aid of interdisciplinary case conferences and the opportunity for exome analysis can be of benefit to people with rare diseases who have not received a definitive diagnosis in a standard care setting. Further improvement of the diagnosis rate can come from whole-genome analysis and from the introduction of an international registry.

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.

"Doctors shouldn't have to cheat the system": Clinicians' real-world experiences of the utility of genomic sequencing

PURPOSE

Emerging genetic tests such as genomic sequencing (GS) can generate a broad range of benefits, but funding criteria only prioritize diagnosis and clinical management. There is limited evidence on all types of benefits obtained from GS in practice. We aimed to explore real-world experiences of Canadian clinicians across specialties on the full range of benefits obtained from the results from GS.

METHODS

We conducted a qualitative study using semistructured interviews with Canadian clinicians. Transcripts were thematically analyzed using constant comparison.

RESULTS

In total, 25 clinicians participated, including 12 geneticists, 7 genetic counselors, 4 oncologists, 1 neurologist, and 1 family physician. Although diagnoses and management were the most valued benefits of GS, clinicians also prioritized nontraditional utility, such as access to community supports. However, clinicians felt "restricted" by funding bodies, which only approved funding when GS would inform diagnoses and management. Consequently, clinicians sought ways to "cheat the system" to access GS (eg, research testing) but acknowledged workarounds were burdensome, drove inequity, and undermined patient care.

CONCLUSION

Current governance structures undervalue real-world benefits of GS leading clinicians to adopt workarounds, which jeopardize patient care. These results support calls for the expansion of the definition of clinical utility and research to quantify the additional benefits.

Whole-exome sequencing and adrenocorticotropic hormone therapy in individuals with infantile spasms

AIM

To identify additional genes associated with infantile spasms using a cohort with defined infantile spasms.

METHOD

Whole-exome sequencing (WES) was performed on 21 consented individuals with infantile spasms and their unaffected parents (a trio-based study). Clinical history and imaging were reviewed. Potentially deleterious exonic variants were identified and segregated. To refine potential candidates, variants were further prioritized on the basis of evidence for relevance to disease phenotype or known associations with infantile spasms, epilepsy, or neurological disease.

RESULTS

Likely pathogenic de novo variants were identified in NR2F1, GNB1, NEUROD2, GABRA2, and NDUFAF5. Suggestive dominant and recessive candidate variants were identified in PEMT, DYNC1I1, ASXL1, RALGAPB, and STRADA; further confirmation is required to support their relevance to disease etiology.

INTERPRETATION

This study supports the utility of WES in uncovering the genetic etiology in undiagnosed individuals with infantile spasms with an overall yield of five out of 21. High-priority candidates were identified in an additional five individuals. WES provides additional support for previously described disease-associated genes and expands their already broad mutational and phenotypic spectrum.

GREEN-DB: a framework for the annotation and prioritization of non-coding regulatory variants from whole-genome sequencing data

Non-coding variants have long been recognized as important contributors to common disease risks, but with the expansion of clinical whole genome sequencing, examples of rare, high-impact non-coding variants are also accumulating. Despite recent advances in the study of regulatory elements and the availability of specialized data collections, the systematic annotation of non-coding variants from genome sequencing remains challenging. Here, we propose a new framework for the prioritization of non-coding regulatory variants that integrates information about regulatory regions with prediction scores and HPO-based prioritization. Firstly, we created a comprehensive collection of annotations for regulatory regions including a database of 2.4 million regulatory elements (GREEN-DB) annotated with controlled gene(s), tissue(s) and associated phenotype(s) where available. Secondly, we calculated a variation constraint metric and showed that constrained regulatory regions associate with disease-associated genes and essential genes from mouse knock-outs. Thirdly, we compared 19 non-coding impact prediction scores providing suggestions for variant prioritization. Finally, we developed a VCF annotation tool (GREEN-VARAN) that can integrate all these elements to annotate variants for their potential regulatory impact. In our evaluation, we show that GREEN-DB can capture previously published disease-associated non-coding variants as well as identify additional candidate disease genes in trio analyses.

The benefit of diagnostic whole genome sequencing in schizophrenia and other psychotic disorders

Schizophrenia has a multifactorial etiology, involving a polygenic architecture. The potential benefit of whole genome sequencing (WGS) in schizophrenia and other psychotic disorders is not well studied. We investigated the yield of clinical WGS analysis in 251 families with a proband diagnosed with schizophrenia (N = 190), schizoaffective disorder (N = 49), or other conditions involving psychosis (N = 48). Participants were recruited in Israel and USA, mainly of Jewish, Arab, and other European ancestries. Trio (parents and proband) WGS was performed for 228 families (90.8%); in the other families, WGS included parents and at least two affected siblings. In the secondary analyses, we evaluated the contribution of rare variant enrichment in particular gene sets, and calculated polygenic risk score (PRS) for schizophrenia. For the primary outcome, diagnostic rate was 6.4%; we found clinically significant, single nucleotide variants (SNVs) or small insertions or deletions (indels) in 14 probands (5.6%), and copy number variants (CNVs) in 2 (0.8%). Significant enrichment of rare loss-of-function variants was observed in a gene set of top schizophrenia candidate genes in affected individuals, compared with population controls (N = 6,840). The PRS for schizophrenia was significantly increased in the affected individuals group, compared to their unaffected relatives. Last, we were also able to provide pharmacogenomics information based on CYP2D6 genotype data for most participants, and determine their antipsychotic metabolizer status. In conclusion, our findings suggest that WGS may have a role in the setting of both research and genetic counseling for individuals with schizophrenia and other psychotic disorders and their families.

Medical costs of children admitted to the neonatal intensive care unit: The role and possible economic impact of WES in early diagnosis

It has been estimated that at least 6.0% of neonates admitted to the Neonatal Intensive Care Unit remains genetically undiagnosed because genetic testing is not routinely performed. The objective of this study is to provide an overview of average healthcare costs for patients admitted to the Neonatal Intensive Care Unit and to assess possible impact of implementing Whole Exome Sequencing (WES) on these total healthcare costs. Hereto, we retrospectively collected postnatal healthcare data of all patients admitted to the level IV Neonatal Intensive Care Unit at the Radboudumc (October 2013-October 2015) and linked unit costs to these healthcare consumptions. Average healthcare costs were calculated and a distinction between patients was made based on performance of genetic tests and the presence of congenital anomalies. Overall, on average €26,627 was spent per patient. Genetic costs accounted for 2.3% of all costs. Healthcare costs were higher for patients with congenital anomalies compared to patients without congenital anomalies. Patients with genetic diagnostics were also more expensive than patients without genetic diagnostics. We next modelled four scenarios based on clinical preselection. First, when performing trio-WES for all patients instead of current diagnostics, overall healthcare costs will increase with 22.2%. Second, performing trio-WES only for patients with multiple congenital anomalies will not result in any cost changes, but this would leave patients with an isolated congenital anomalies untested. We therefore next modelled a scenario performing trio-WES for all patients with congenital anomalies, increasing the average per patient healthcare costs by 5.3%. This will rise to a maximum of 5.5% when also modelling for an extra genetic test for clinically selected patients to establish genetic diagnoses that are undetectable by WES. In conclusion, genetic diagnostic testing accounted for a small fraction of total costs. Implementation of trio-WES as first-tier test for all patients with congenital anomalies will lead to a limited increase in overall healthcare budget, but will facilitate personalized treatments options guided by the diagnoses made.

Prevalence of monogenic disease in paediatric patients with a predominant respiratory phenotype

OBJECTIVE

This study aimed to investigate the prevalence and clinical characteristics of monogenic disease in paediatric patients with a predominant respiratory phenotype.

METHODS

Exome sequencing was performed in a cohort of 971 children with a predominant respiratory phenotype and suspected genetic aetiology. A total of 140 positive cases were divided into subgroups based on recruitment age and the primary biological system(s) involved.

RESULTS

There were 140 (14.4%) patients with a positive molecular diagnosis, and their primary clinical manifestations were respiratory distress (12.9%, 18 of 140), respiratory failure (12.9%, 18 of 140) and recurrent/persistent lower respiratory infections (66.4%, 93 of 140). Primary immunodeficiency (49.3%), multisystem malformations/syndromes (17.9%), and genetic lung disease (16.4%) were the three most common genetic causes in the cohort, and they varied among the age subgroups. A total of 72 (51.4%) patients had changes in medical management strategies after genetic diagnosis, and the rate in those with genetic lung disease (82.6%, 19 of 23) was far higher than that in patients with genetic disease with lung involvement (45.3%, 53 of 117) (p=0.001).

CONCLUSION

Our findings demonstrate that exome sequencing is a valuable diagnostic tool for monogenic diseases in children with a predominant respiratory phenotype, and the genetic spectrum varies with age. Taken together, genetic diagnoses provide invaluable clinical and prognostic information that may also facilitate the development of precision medicine for paediatric patients.

What Has the Undiagnosed Diseases Network Taught Us About the Clinical Applications of Genomic Testing?

Genetic testing has undergone a revolution in the last decade, particularly with the advent of next-generation sequencing and its associated reductions in costs and increases in efficiencies. The Undiagnosed Diseases Network (UDN) has been a leader in the application of such genomic testing for rare disease diagnosis. This review discusses the current state of genomic testing performed within the UDN, with a focus on the strengths and limitations of whole-exome and whole-genome sequencing in clinical diagnostics and the importance of ongoing data reanalysis. The role of emerging technologies such as RNA and long-read sequencing to further improve diagnostic rates in the UDN is also described. This review concludes with a discussion of the challenges faced in insurance coverage of comprehensive genomic testing as well as the opportunities for a larger role of testing in clinical medicine.

Cost-effectiveness of whole-exome sequencing in progressive neurological disorders of children

OBJECTIVES

To clarify the diagnostic utility and the cost-effectiveness of whole-exome sequencing (WES) as a routine early-diagnostic tool in children with progressive neurological disorders.

METHODS

Patients with infantile-onset severe neurological diseases or childhood-onset progressive neurological disorders were prospectively recruited to this WES study, in the pediatric neurology clinic at Helsinki University Hospital during 2016-2018. A total of 48 patients underwent a singleton WES. A control group of 49 children underwent traditional diagnostic examinations and were retrospectively collected from the hospital records. Their use of health care services, related to the diagnostic process, was gathered. Incremental cost-effectiveness ratio (ICER) per additional diagnosis was calculated from the health care provider perspective. Bootstrapping methods were used to estimate the uncertainty of cost-effectiveness outcomes.

RESULTS

WES provided a better diagnostic yield (38%) than diagnostic pathway that did not prioritize WES in early diagnosis (25%). WES outperformed other diagnostic paths especially when made early, within one year of first admission (44%). Cost-effectiveness in our results are conservative, affected by WES costs during 2016-18.

CONCLUSIONS

WES is an efficient and cost-effective diagnostic tool that should be prioritized in early diagnostic path of children with progressive neurological disorders. The progressively decreasing price of the test improves cost-effectiveness further.

Mixed-methods evaluation of the NHS Genomic Medicine Service for paediatric rare diseases: study protocol

Background

A new nationally commissioned NHS England Genomic Medicine Service (GMS) was recently established to deliver genomic testing with equity of access for patients affected by rare diseases and cancer. The overarching aim of this research is to evaluate the implementation of the GMS during its early years, identify barriers and enablers to successful implementation, and provide recommendations for practice. The focus will be on the use of genomic testing for paediatric rare diseases.

Methods

This will be a four-year mixed-methods research programme using clinic observations, interviews and surveys. Study 1 consists of qualitative interviews with designers/implementers of the GMS in Year 1 of the research programme, along with documentary analysis to understand the intended outcomes for the Service. These will be revisited in Year 4 to compare intended outcomes with what happened in practice, and to identify barriers and facilitators that were encountered along the way. Study 2 consists of clinic observations (pre-test counselling and results disclosure) to examine the interaction between health professionals and parents, along with follow-up interviews with both after each observation. Study 3 consists of a longitudinal survey with parents at two timepoints (time of testing and 12 months post-results) along with follow-up interviews, to examine parent-reported experiences and outcomes. Study 4 consists of qualitative interviews and a cross-sectional survey with medical specialists to identify preparedness, facilitators and challenges to mainstreaming genomic testing. The use of theory-based and pre-specified constructs will help generalise the findings and enable integration across the various sub-studies.

Dissemination

We will disseminate our results to policymakers as findings emerge, so any suggested changes to service provision can be considered in a timely manner. A workshop with key stakeholders will be held in Year 4 to develop and agree a set of recommendations for practice.

Lessons learnt from multifaceted diagnostic approaches to the first 150 families in Victoria's Undiagnosed Diseases Program

BACKGROUND

Clinical exome sequencing typically achieves diagnostic yields of 30%-57.5% in individuals with monogenic rare diseases. Undiagnosed diseases programmes implement strategies to improve diagnostic outcomes for these individuals.

AIM

We share the lessons learnt from the first 3 years of the Undiagnosed Diseases Program-Victoria, an Australian programme embedded within a clinical genetics service in the state of Victoria with a focus on paediatric rare diseases.

METHODS

We enrolled families who remained without a diagnosis after clinical genomic (panel, exome or genome) sequencing between 2016 and 2018. We used family-based exome sequencing (family ES), family-based genome sequencing (family GS), RNA sequencing (RNA-seq) and high-resolution chromosomal microarray (CMA) with research-based analysis.

RESULTS

In 150 families, we achieved a diagnosis or strong candidate in 64 (42.7%) (37 in known genes with a consistent phenotype, 3 in known genes with a novel phenotype and 24 in novel disease genes). Fifty-four diagnoses or strong candidates were made by family ES, six by family GS with RNA-seq, two by high-resolution CMA and two by data reanalysis.

CONCLUSION

We share our lessons learnt from the programme. Flexible implementation of multiple strategies allowed for scalability and response to the availability of new technologies. Broad implementation of family ES with research-based analysis showed promising yields post a negative clinical singleton ES. RNA-seq offered multiple benefits in family ES-negative populations. International data sharing strategies were critical in facilitating collaborations to establish novel disease-gene associations. Finally, the integrated approach of a multiskilled, multidisciplinary team was fundamental to having diverse perspectives and strategic decision-making.

Conceptualization of utility in translational clinical genomics research

Prior to integration into clinical care, a novel medical innovation is typically assessed in terms of its balance of benefits and risks, often referred to as utility. Members of multidisciplinary research teams may conceptualize and assess utility in different ways, which has implications within the translational genomics community and for the evidence base upon which clinical guidelines groups and healthcare payers make decisions. Ambiguity in the conceptualization of utility in translational genomics research can lead to communication challenges within research teams and to study designs that do not meet stakeholder needs. We seek to address the ambiguity challenge by describing the conceptual understanding of utility and use of the term by scholars in the fields of philosophy, medicine, and the social sciences of decision psychology and health economics. We illustrate applications of each field's orientation to translational genomics research by using examples from the Clinical Sequencing Evidence-Generating Research (CSER) consortium, and we provide recommendations for increasing clarity and cohesion in future research. Given that different understandings of utility will align to a greater or lesser degree with important stakeholders' views, more precise use of the term can help researchers to better integrate multidisciplinary investigations and communicate with stakeholders.

Clinical and therapeutic significance of genetic variation in the GRIN gene family encoding NMDARs

Considerable genetic variation of N-methyl-d-aspartate receptors (NMDARs) has recently become apparent, with many hundreds of de novo variants identified through widely available clinical genetic testing. Individuals with GRIN variants present with neurological conditions such as epilepsy, autism, intellectual disability (ID), movement disorders, schizophrenia and behavioral disorders. Determination of the functional consequence of genetic variation for NMDARs should lead to precision therapeutics. Furthermore, genetic animal models harboring human variants have the potential to reveal mechanisms that are shared among different neurological conditions, providing strategies that may allow treatment of individuals who are refractory to therapy. Preclinical studies in animal models and small open label trials in humans support this idea. However, additional functional data for variants and animal models corresponding to multiple individuals with the same genotype are needed to validate this approach and to lead to thoughtfully designed, randomized, placebo-controlled clinical trials, which could provide data in order to determine safety and efficacy of potential precision therapeutics.

Diagnostic yield from routine metabolic screening tests in evaluation of global developmental delay and intellectual disability

Global developmental delay and intellectual disability (GDD/ID) affect 3% of the paediatric population. Although inborn errors of metabolism (IEM) are not a common cause of GDD/ID, early therapeutic intervention can improve neurodevelopmental manifestations. In 2012, a first-tier test panel, including specialized metabolic and routine chemistry tests, was piloted to community-based paediatricians in British Columbia with aims to achieve earlier diagnosis of treatable IEM.

Objective

The aim of this retrospective review was to evaluate the diagnostic yield from these first-tier tests in the 7 years before (2006 to 2012) and after (2013 to 2019) implementation at the community paediatrician level.

Results

Prior and postimplementation diagnostic yield of an IEM from first-tier metabolic testing was 9 out of 986 (0.91%) and 11 out of 4,345 children (0.25%), respectively. Disorders of creatine metabolism and organic acidurias were the most frequently established diagnoses in both time periods. No diagnoses were established through acylcarnitine copper/ceruloplasmin, lactate, or ammonia testing. Twenty out of 24 patients had specific neurological or other red flag signs in addition to GDD/ID. Four boys diagnosed with an x-linked creatine transporter defect (CTD) had speech-language delay as the most prominent finding.

Conclusions

The expansion of first-tier metabolic testing to community-based paediatricians in BC did not yield an increase in IEM diagnoses. A modified first-tier test panel should be offered to patients with GDD/ID, neurologic, and/or red flag signs. Urine creatine testing in boys with speech-language delay warrants consideration to detect CTD.

Perceived Utility of Genomic Sequencing: Qualitative Analysis and Synthesis of a Conceptual Model to Inform Patient-Centered Instrument Development

BACKGROUND AND OBJECTIVES

Successful clinical integration of genomic sequencing (GS) requires evidence of its utility. While GS potentially has benefits (utilities) or harms (disutilities) across multiple domains of life for both patients and their families, there is as yet no empirically informed conceptual model of these effects. Our objective was to develop an empirically informed conceptual model of perceived utility of GS that captures utilities and disutilities for patients and their families across diverse backgrounds.

METHODS

We took a patient-centered approach, in which we began with a review of existing literature followed by collection of primary interview data. We conducted semi-structured interviews to explore types of utility in a clinically and sociopolitically diverse sample of 60 adults from seven Clinical Sequencing Evidence-Generating Research (CSER) consortium projects. Interviewees had either personally received, or were parents of a child who had received, GS results. Qualitative data were analyzed using thematic analysis. Findings from interviews were integrated with existing literature on clinical and personal utility to form the basis of an initial conceptual model that was refined based on expert review and feedback.

RESULTS

Five key utility types that have been previously identified in qualitative literature held up as primary domains of utility and disutility in our diverse sample. Interview data were used to specify and organize subdomains of an initial conceptual model. After expert refinement, the five primary domains included in the final model are clinical, emotional, behavioral, cognitive, and social, and several subdomains are specified within each.

CONCLUSION

We present an empirically informed conceptual model of perceived utility of GS. This model can be used to guide development of instruments for patient-centered outcome measurement that capture the range of relevant utilities and disutilities and inform clinical implementation of GS.

Randomized prospective evaluation of genome sequencing versus standard-of-care as a first molecular diagnostic test

PURPOSE

To evaluate the diagnostic yield and clinical relevance of clinical genome sequencing (cGS) as a first genetic test for patients with suspected monogenic disorders.

METHODS

We conducted a prospective randomized study with pediatric and adult patients recruited from genetics clinics at Massachusetts General Hospital who were undergoing planned genetic testing. Participants were randomized into two groups: standard-of-care genetic testing (SOC) only or SOC and cGS.

RESULTS

Two hundred four participants were enrolled, 202 were randomized to one of the intervention arms, and 99 received cGS. In total, cGS returned 16 molecular diagnoses that fully or partially explained the indication for testing in 16 individuals (16.2% of the cohort, 95% confidence interval [CI] 8.9-23.4%), which was not significantly different from SOC (18.2%, 95% CI 10.6-25.8%, P = 0.71). An additional eight molecular diagnoses reported by cGS had uncertain relevance to the participant's phenotype. Nevertheless, referring providers considered 20/24 total cGS molecular diagnoses (83%) to be explanatory for clinical features or worthy of additional workup.

CONCLUSION

cGS is technically suitable as a first genetic test. In our cohort, diagnostic yield was not significantly different from SOC. Further studies addressing other variant types and implementation challenges are needed to support feasibility and utility of broad-scale cGS adoption.