Microcosting diagnostic genomic sequencing: A systematic review

PurposeMicrocosting can provide valuable economic evidence to inform the translation of genomic sequencing to clinical practice. A systematic literature review was conducted to identify studies employing microcosting methods to estimate the cost of genomic sequencing to diagnose cancer and rare diseases.MethodsFour electronic databases, Medline, Embase, EconLit, and Cumulated Index to Nursing and Allied Health Literature were searched. Reference lists of identified studies were also searched. Studies were included if they had estimated the cost of genome sequencing or exome sequencing for cancer or rare disease diagnosis using microcosting methods.ResultsSeven studies met the inclusion criteria. Cost estimates for genome sequencing and exome sequencing ranged between US$2094 and $9706 and US$716 and $4817 per patient, respectively. All studies disaggregated resource use and cost inputs into labor, equipment, and consumables, with consumables being the main cost component. Considerable differences in the level of detail used to report the steps and resources used in each of the sequencing steps limited study comparisons.ConclusionDefining a standard microcosting methodology is challenging because of the heterogeneous nature of genomic sequencing. Reporting of detailed and complete sequencing procedures, inclusion of sensitivity analyses and clear justifications of resource use, and measurement of unit costs can improve comparability, transferability, and generalizability of study findings.     

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

PurposeAdoption 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.MethodsProbands with neurologic, cardiac, or immunologic conditions were offered GS and TGP testing. Diagnostic yield was compared using a fully paired study design.ResultsA 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.ConclusionGS may yield up to twice as many diagnoses in pediatric patients compared with TGP testing but not yet across all population groups.     

Estimating diagnostic noise in panel-based genomic analysis

PurposeGene panels with a series of strict variant filtering rules are often used for clinical analysis of exomes and genomes. Panel sizes vary, affecting the test’s sensitivity and specificity. We investigated the background rate of candidate variants in a population setting using gene panels developed to diagnose a range of heterogeneous monogenic diseases.MethodsWe used the Gene2Phenotype database with the Variant Effect Predictor plugin to identify rare nonsynonymous variants in exome sequence data from 200,643 individuals in UK Biobank. We evaluated 5 clinically curated gene panels of varying sizes (50-1700 genes).ResultsBigger gene panels resulted in more prioritized variants, varying from an average of approximately 0.3 to 3.5 variants per person. The number of individuals with prioritized variants varied linearly with coding sequence length for monoallelic genes (～300 individuals per 1000 base pairs) and quadratically for biallelic genes, with notable outliers.ConclusionAlthough large gene panels may be the best strategy to maximize diagnostic yield in genetically heterogeneous diseases, they frequently prioritize likely benign variants requiring follow up. Most individuals have ≥1 rare nonsynonymous variant in panels containing >500 disease genes. Extreme caution should be applied when interpreting candidate variants, particularly in the absence of relevant phenotypes.     

Comprehensive high-resolution genomic profiling and cytogenetics of two pediatric and one adult medulloblastoma

Medulloblastoma (WHO grade IV) is a rare, malignant, invasive, embryonal tumor which mainly occurs in children and represents less than 1% of all adult brain tumors. Systematic comprehensive genetic analyses on medulloblastomas are rare but necessary to provide more detailed information.     

Factors associated with the time to complete clinical exome sequencing in a pediatric patient population

PurposeExome sequencing (ES) is becoming increasingly important for diagnosing rare genetic disorders. Patients and clinicians face several barriers when attempting to obtain ES. This study is aimed to describe factors associated with a longer time interval between provider recommendation of testing and sample collection for ES.MethodsA retrospective chart review was conducted for insurance-authorized, completed pediatric ES in which initial requests were reviewed by Stanford’s Genetic Testing Optimization Service between November 2018 and December 2019. Regression analysis was used to determine the association between the geocoded median household income and 3 different time point intervals defined as time to test, insurance decision, and scheduling/consent.ResultsOf the 281 charts reviewed, 115 cases were included in the final cohort. The average time from provider preauthorization request to sample collection took 104.4 days, and income was negatively correlated with the length of the insurance decision interval.ConclusionPediatric patients undergo a lengthy, uncertain process when attempting to obtain ES, some of which is associated with income. More research and clinician interventions are required to clarify specific socioeconomic factors that influence the ability to obtain timely ES and develop optimal protocols.     

The Clinical Variant Analysis Tool: Analyzing the evidence supporting reported genomic variation in clinical practice

PurposeGenomic test results, regardless of laboratory variant classification, require clinical practitioners to judge the applicability of a variant for medical decisions. Teaching and standardizing clinical interpretation of genomic variation calls for a methodology or tool.MethodsTo generate such a tool, we distilled the Clinical Genome Resource framework of causality and the American College of Medical Genetics/Association of Molecular Pathology and Quest Diagnostic Laboratory scoring of variant deleteriousness into the Clinical Variant Analysis Tool (CVAT). Applying this to 289 clinical exome reports, we compared the performance of junior practitioners with that of experienced medical geneticists and assessed the utility of reported variants.ResultsCVAT enabled performance comparable to that of experienced medical geneticists. In total, 124 of 289 (42.9%) exome reports and 146 of 382 (38.2%) reported variants supported a diagnosis. Overall, 10.5% (1 pathogenic [P] or likely pathogenic [LP] variant and 39 variants of uncertain significance [VUS]) of variants were reported in genes without established disease association; 20.2% (23 P/LP and 54 VUS) were in genes without sufficient phenotypic concordance; 7.3% (15 P/LP and 13 VUS) conflicted with the known molecular disease mechanism; and 24% (91 VUS) had insufficient evidence for deleteriousness.ConclusionImplementation of CVAT standardized clinical interpretation of genomic variation and emphasized the need for collaborative and transparent reporting of genomic variation.     

Detection of mosaic variants using genome sequencing in a large pediatric cohort

The increased use of next-generation sequencing has expanded our understanding of the involvement and prevalence of mosaicism in genetic disorders. We describe a total of eleven cases: nine in which mosaic variants detected by genome sequencing (GS) and/or targeted gene panels (TGPs) were considered to be causative for the proband's phenotype, and two of apparent parental mosaicism. Variants were identified in the following genes: PHACTR1, SCN8A, KCNT1, CDKL5, NEXMIF, CUX1, TSC2, GABRB2, and SMARCB1. In addition, we identified one large duplication including three genes, UBE3A, GABRB3, and MAGEL2, and one large deletion including deletion of ARFGAP1, EEF1A2, CHRNA4, and KCNQ2. All patients were enrolled in the NYCKidSeq study, a research program studying the communication of genomic information in clinical care, as well as the clinical utility and diagnostic yield of GS for children with suspected genetic disorders in diverse populations in New York City. We observed variability in the correlation between reported variant allele fraction and the severity of the patient's phenotype, although we were not able to determine the mosaicism percentage in clinically relevant tissue(s). Although our study was not sufficiently powered to assess differences in mosaicism detection between the two testing modalities, we saw a trend toward better detection by GS as compared with TGP testing. This case series supports the importance of mosaicism in childhood-onset genetic conditions and informs guidelines for laboratory and clinical interpretation of mosaic variants detected by GS.     

The diagnostic utility of genome sequencing in a pediatric cohort with suspected mitochondrial disease

PurposeThe utility of genome sequencing (GS) in the diagnosis of suspected pediatric mitochondrial disease (MD) was investigated.MethodsAn Australian cohort of 40 pediatric patients with clinical features suggestive of MD were classified using the modified Nijmegen mitochondrial disease severity scoring into definite (17), probable (17), and possible (6) MD groups. Trio GS was performed using DNA extracted from patient and parent blood. Data were analyzed for single-nucleotide variants, indels, mitochondrial DNA variants, and structural variants.ResultsA definitive MD gene molecular diagnosis was made in 15 cases and a likely MD molecular diagnosis in a further five cases. Causative mitochondrial DNA (mtDNA) variants were identified in four of these cases. Three potential novel MD genes were identified. In seven cases, causative variants were identified in known disease genes with no previous evidence of causing a primary MD. Diagnostic rates were higher in patients classified as having definite MD.ConclusionGS efficiently identifies variants in MD genes of both nuclear and mitochondrial origin. A likely molecular diagnosis was identified in 67% of cases and a definitive molecular diagnosis achieved in 55% of cases. This study highlights the value of GS for a phenotypically and genetically heterogeneous disorder like MD.     

The difficulties of broad data sharing in genomic medicine: Empirical evidence from diverse participants in prenatal and pediatric clinical genomics research

PurposeThis study aimed to understand broad data sharing decisions among predominantly underserved families participating in genomic research.MethodsDrawing on clinic observations, semistructured interviews, and survey data from prenatal and pediatric families enrolled in a genomic medicine study focused on historically underserved and underrepresented populations, this paper expands empirical evidence regarding genomic data sharing communication and decision-making.ResultsOne-third of parents declined to share family data, and pediatric participants were significantly more likely to decline than prenatal participants. The pediatric population was significantly more socioeconomically disadvantaged and more likely to require interpreters. Opt-in was tied to altruism and participants’ perception that data sharing was inherent to research participation. Opt-out was associated with privacy concerns and influenced by clinical staff’s presentation of data handling procedures. The ability of participants to make informed choices during enrollment about data sharing was weakened by suboptimal circumstances, which was revealed by poor understanding of data sharing in follow-up interviews as well as discrepancies between expressed participant desires and official recorded choices.ConclusionThese empirical data suggest that the context within which informed consent process is conducted in clinical genomics may be inadequate for respecting participants’ values and preferences and does not support informed decision-making processes.     

A cost-effectiveness analysis of genomic sequencing in a prospective versus historical cohort of complex pediatric patients

PurposeCost-effectiveness evaluations of first-line genomic sequencing (GS) in the diagnosis of children with genetic conditions are limited by the lack of well-defined comparative cohorts. We sought to evaluate the cost-effectiveness of early GS in pediatric patients with complex monogenic conditions compared with a matched historical cohort.MethodsData, including investigation costs, were collected in a prospective cohort of 92 pediatric patients undergoing singleton GS over an 18-month period (2016–2017) with two of the following: a condition with high mortality, multisystem disease involving three or more organs, or severe limitation of daily function. Comparative data were collected in a matched historical cohort who underwent traditional investigations in the years 2012–2013.ResultsGS yielded a diagnosis in 42% while traditional investigations yielded a diagnosis in 23% (p = 0.003). A change in management was experienced by 74% of patients diagnosed following GS, compared with 32% diagnosed following traditional investigations. Singleton GS at a cost of AU$3100 resulted in a mean saving per person of AU$3602 (95% confidence interval [CI] AU$2520–4685). Cost savings occurred across all investigation subtypes and were only minimally offset by clinical management costs.ConclusionGS in complex pediatric patients saves significant costs and doubles the diagnostic yield of traditional approaches.     

Australian public perspectives on genomic data storage and sharing: Benefits,concerns and access preferences

Diagnostic genomic sequencing generates unprecedented amounts of data. In addition to its primary use, this data could be used for a wide range of secondary purposes, including research and informing future healthcare for the data donor. These opportunities may require data to be shared with third parties. Although effective data sharing relies on public support, there are barriers which may prevent people from choosing to donate their genomic data and surprisingly few studies explore these barriers in depth.To address this need, this study aimed to qualitatively explore the Australian public's views and preferences for storing and sharing genomic data. Online focus groups were recorded, transcribed, and analysed using inductive content analysis.A total of 7 focus groups were conducted with 39 members of the Australian public ranging from 18 to 67 years of age. Participants were mostly supportive of genomic data being stored and shared for secondary purposes, recognising the potential benefits for individual health and wider medical research. However, some concerns were identified. Participants felt genomic data was particularly sensitive information, and raised the potential for discrimination, stigma, and other malicious uses of such data. Concerns for privacy and security of the data were also prevalent.Trustworthiness of data users was important when considering who genomic data should be shared with. Although participants were supportive of data being freely available to health professionals and researchers, they were opposed to insurance companies and employers accessing the data. There was greater controversy around sharing data with law enforcement and pharmaceutical companies. Participants recognised both benefits and harms to sharing with law enforcement. They were also cognizant of the dual purpose of pharmaceutical companies as both research and profit-driven organisations. Finally, participants expressed varying perspectives about sharing genomic data with family members, yet most agreed that explicit consent from the data donor should be required to share their information with relatives.This study highlighted several of the Australian public's perceived barriers and motivators for the storage and sharing of genomic data. Participants recognised both the benefits of collecting, storing and sharing such data widely but also the potential for harm from data misuse. While public acceptance of such endeavours is required to maximise the volume of data made available, the concerns around data access and security need to be addressed before this can occur. These findings also highlight the nuance and ethical complexity of decisions about who we should allow to access donated genomic data. These perspectives will be essential in helping to shape the way large-scale genomic data storage and sharing is developed and implemented in Australia, and internationally.     

Towards a privacy preserving cohort discovery framework for clinical research networks

BackgroundThe last few years have witnessed an increasing number of clinical research networks (CRNs) focused on building large collections of data from electronic health records (EHRs), claims, and patient-reported outcomes (PROs). Many of these CRNs provide a service for the discovery of research cohorts with various health conditions, which is especially useful for rare diseases.Supporting patient privacy can enhance the scalability and efficiency of such processes; however, current practice mainly relies on policy, such as guidelines defined in the Health Insurance Portability and Accountability Act (HIPAA), which are insufficient for CRNs (e.g., HIPAA does not require encryption of data – which can mitigate insider threats). By combining policy with privacy enhancing technologies we can enhance the trustworthiness of CRNs. The goal of this research is to determine if searchable encryption can instill privacy in CRNs without sacrificing their usability.MethodsWe developed a technique, implemented in working software to enable privacy-preserving cohort discovery (PPCD) services in large distributed CRNs based on elliptic curve cryptography (ECC). This technique also incorporates a block indexing strategy to improve the performance (in terms of computational running time) of PPCD. We evaluated the PPCD service with three real cohort definitions: (1) elderly cervical cancer patients who underwent radical hysterectomy, (2) oropharyngeal and tongue cancer patients who underwent robotic transoral surgery, and (3) female breast cancer patients who underwent mastectomy) with varied query complexity. These definitions were tested in an encrypted database of 7.1 million records derived from the publically available Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS). We assessed the performance of the PPCD service in terms of (1) accuracy in cohort discovery, (2) computational running time, and (3) privacy afforded to the underlying records during PPCD.ResultsThe empirical results indicate that the proposed PPCD can execute cohort discovery queries in a reasonable amount of time, with query runtime in the range of 165–262 s for the 3 use cases, with zero compromise in accuracy. We further show that the search performance is practical because it supports a highly parallelized design for secure evaluation over encrypted records. Additionally, our security analysis shows that the proposed construction is resilient to standard adversaries.ConclusionsPPCD services can be designed for clinical research networks. The security construction presented in this work specifically achieves high privacy guarantees by preventing both threats originating from within and beyond the network.     

Analysis of potential genomic confounding in genetic association studies and an online genomic confounding browser (GCB)

Genome-wide association studies have transformed genetic studies of disease susceptibility, identifying many variants that may tag functional polymorphism nearby. Variants are often ascribed to a physically close gene exhibiting plausible functionality for a causal pathway. However, more physically remote genes may be at a lesser linkage or linkage disequilibrium (LD) distance from the tested SNP and could therefore contain the functional variant tagged. This analysis aims to identify instances where research may be misled by misassociation of a variant with a gene and develop tools to analyse genomic confounding. A catalogue of reported associations was systematically analysed for unreported genes which may represent the true functionality ascribed to a reported variant, calculating physical and genetic distances for all genes within 1 cM of the tagging polymorphism. Results revealed 55 SNPs where recombination was lower between the identified SNP and a physically more remote gene than initially reported, and 374 where an alternative gene was genetically and physically closer than the reported gene. Analyses show potential for genomic confounding through false inferences of variant association to a gene. An online visualization tool (http://gcb.genes.org.uk/) was developed to plot genes by physical and genetic distance relative to a variant, along with LD data.     

The SickKids Genome Clinic: developing and evaluating a pediatric model for individualized genomic medicine

Our increasing knowledge of how genomic variants affect human health and the falling costs of whole‐genome sequencing are driving the development of individualized genomic medicine. This new clinical paradigm uses knowledge of an individual's genomic variants to anticipate, diagnose and manage disease. While individualized genetic medicine offers the promise of transformative change in health care, it forces us to reconsider existing ethical, scientific and clinical paradigms. The potential benefits of pre‐symptomatic identification of at‐risk individuals, improved diagnostics, individualized therapy, accurate prognosis and avoidance of adverse drug reactions coexist with the potential risks of uninterpretable results, psychological harm, outmoded counseling models and increased health care costs. Here we review the challenges, opportunities and limits of integrating genomic analysis into pediatric clinical practice and describe a model for implementing individualized genomic medicine. Our multidisciplinary team of bioinformaticians, health economists, health services and policy researchers, ethicists, geneticists, genetic counselors and clinicians has designed a ‘Genome Clinic’ research project that addresses multiple challenges in pediatric genomic medicine – ranging from development of bioinformatics tools for the clinical assessment of genomic variants and the discovery of disease genes to health policy inquiries, assessment of clinical care models, patient preference and the ethics of consent.     

Meta-analysis of the diagnostic and clinical utility of exome and genome sequencing in pediatric and adult patients with rare diseases across diverse populations

PurposeThis meta-analysis aims to compare the diagnostic and clinical utility of exome sequencing (ES) vs genome sequencing (GS) in pediatric and adult patients with rare diseases across diverse populations.MethodsA meta-analysis was conducted to identify studies from 2011 to 2021.ResultsOne hundred sixty-one studies across 31 countries/regions were eligible, featuring 50,417 probands of diverse populations. Diagnostic rates of ES (0.38, 95% CI 0.36-0.40) and GS (0.34, 95% CI 0.30-0.38) were similar (P = .1). Within-cohort comparison illustrated 1.2-times odds of diagnosis by GS over ES (95% CI 0.79-1.83, P = .38). GS studies discovered a higher range of novel genes than ES studies; yet, the rate of variant of unknown significance did not differ (P = .78). Among high-quality studies, clinical utility of GS (0.77, 95% CI 0.64-0.90) was higher than that of ES (0.44, 95% CI 0.30-0.58) (P < .01).ConclusionThis meta-analysis provides an important update to demonstrate the similar diagnostic rates between ES and GS and the higher clinical utility of GS over ES. With the newly published recommendations for clinical interpretation of variants found in noncoding regions of the genome and the trend of decreasing variant of unknown significance and GS cost, it is expected that GS will be more widely used in clinical settings.     

Factors that promote and prohibit access to participants in the clinical setting: a review of response rates from a health communication intervention study

Objective

This report examines the factors that influence researchers’ abilities to recruit participants into health communication studies conducted within the clinical setting.

Method

Review of response rates over a 15 month data collection period for an intervention study on patient-physician communication, low health literacy, and diabetes management.

Results

Most patients were willing to participate (73%). The challenge was not fostering interest in the study, but rather being able to approach potential participants. Over the course of the study, patients with diabetes visited the clinic 1263 times yet interviewers were only able to approach patients 196 times for potential inclusion in the study. Confounding factors that affected recruiting participants included the interviewers’ availability and clinic schedule, as well as patient chief complaint and no show or rescheduling rates.

Conclusion

Researchers must engage in collaborative efforts with clinic staff during the research design phase, maximize their availability to approach potential patients, and capitalize on the insights of clinic staff to approach those patients who fit the study criteria and would be most willing to participate in the research project.

Practice implications

Researchers must learn about the clinic, reduce research burden, and be flexible to work within the constraints of the clinic setting.     

Theory-driven research in pediatric psychology: a little bit on why and how.

Introduces a Special Issue, covering two published issues (5 and 6) of this journal, on theory-driven research in pediatric psychology. A rationale for conducting research from a conceptual basis is presented. It is emphasized that science is primarily an intellectual activity, demonstrated in the form of theory building, testing, and reformulation. Furthermore, it is argued theory serves as a planning and communication aide for scientific pursuit. The process and components of theory-driven research are then highlighted. Theoretical constructs, theoretical and empirical definitions of constructs, and the use of variables are discussed. A definition of scientific theory is offered. Theory testing is distinguished from post hoc theorizing. Differences in the scope of theories are noted. Connections between theory and hypothesis testing and research design are addressed, especially for nonexperimental or correlational research.     

Targeted resequencing of 358 candidate genes for autism spectrum disorder in a Chinese cohort reveals diagnostic potential and genotype–phenotype correlations

Autism spectrum disorder (ASD) is a childhood neuropsychiatric disorder with a complex genetic architecture. The diagnostic potential of a targeted panel of ASD genes has only been evaluated in small cohorts to date and is especially understudied in the Chinese population. Here , we designed a capture panel with 358 genes (111 syndromic and 247 nonsyndromic) for ASD and sequenced a Chinese cohort of 539 cases evaluated with the Autism Diagnostic Interview‐Revised (ADI‐R) and the Autism Diagnostic Observation Schedule (ADOS) as well as 512 controls. ASD cases were found to carry significantly more ultra‐rare functional variants than controls. A subset of 78 syndromic and 54 nonsyndromic genes was the most significantly associated and should be given high priority in the future screening of ASD patients. Pathogenic and likely pathogenic variants were detected in 9.5% of cases. Variants in SHANK3 and SHANK2 were the most frequent, especially in females, and occurred in 1.2% of cases. Duplications of 15q11–13 were detected in 0.8% of cases. Variants in CNTNAP2 and MEF2C were correlated with epilepsy/tics in cases. Our findings reveal the diagnostic potential of ASD genetic panel testing and new insights regarding the variant spectrum. Genotype–phenotype correlations may facilitate the diagnosis and management of ASD.     

Involving patients and their families in deciding to use next generation sequencing: Results from a nationally representative survey of U.S. oncologists

ObjectiveNext generation sequencing (NGS) may aid in tumor classification and treatment. Barriers to shared decision-making may influence use of NGS. We examined, from oncologists’ perspectives, whether barriers to involving patients/families in decision-making were associated with NGS use.MethodsUsing data from the first national survey of medical oncologists’ perspectives on precision medicine (N = 1281), we approached our analyses in two phases. Bivariate analyses initially evaluated associations between barriers to involving patients/families in deciding to use NGS and provider- and organizational-level characteristics. Modified Poisson regressions then examined associations between patient/family barriers and NGS use.ResultsApproximately 59 % of oncologists reported at least one barrier to involving patients/families in decision-making regarding NGS use. Those reporting patient/family barriers tended to have fewer genomic resources at their practices, to be in rural or suburban areas, and to have a higher proportion of Medicaid patients. However, these barriers were not associated with NGS use.ConclusionsOncologists encounter barriers to involving patients/families in NGS testing decisions. Organizational barriers may also potentially play a role in testing decisions.Practice implicationsTo foster patient-centered care, strategies to support patient involvement in genomic testing decisions are needed, particularly among practices in low-resource settings.