Clinical Genome Sequencing Research Articles

Feasibility of whole-genome sequencing in routine clinical practice.

3013 Background: In the next few years numerous drugs will be approved for defined genomic targets, most of these in a tumor agnostic manner. Identifying patients who can benefit from this is critical for the future success of precision medicine, ideally using a single comprehensive test to detect all possible biomarkers. The WIDE study (WGS Implementation in standard cancer Diagnostics for Every cancer patient) aimed to evaluate the feasibility, clinical validity (primary endpoints) and added value (secondary endpoint) of clinical grade Whole Genome Sequencing (cWGS) in routine clinical practice. Methods: cWGS was prospectively performed on 1,200 consecutive patients with (suspected) metastatic cancer. Tumor material was obtained during routine clinical procedures for both Standard-Of-Care (SOC) and cWGS. Next to securing a high quality specimen for SOC diagnostics, multiple frozen sections per patient were evaluated to identify the sample most suitable for WGS. cWGS was conducted independently of, but in parallel with SOC diagnostics, which included SOC molecular diagnostics (Moldx) for 48% of patients. cWGS and MolDx results were compared and discussed in a dedicated tumor board. Additional tests for resolving discordances were applied when needed. Results: cWGS was successfully performed in 69% (841/1217) of samples with a technical success rate of 97% (841/871). An insufficient amount of tumor cells ( < 20%) was the main reason for not completing cWGS (25%, 310/1217). cWGS turn-around-time (TAT), due to continuous improvements to the clinical procedure and cWGS pipeline over the course of the study, decreased to 10 working days. A total of 856 genomic biomarkers identified by SOC MolDx could be compared to cWGS results. Initial analyses of discordances revealed an error rate of 2.1% (18/856) for cWGS compared to a 1.0% (8/856) error rate for SOC Moldx. After optimizing cWGS and SOC pipelines based on these findings, error rates dropped to 0.6% (5/856) and 0.7% (6/856) for cWGS and SOC MolDx, respectively. Overall, cWGS identified clinically actionable (routine practice and experimental) biomarkers in 71% of all patients tested. Compared to SOC MolDx, cWGS identified one or more additional clinically actionable biomarkers in 54% (446/832) of patients. Interestingly, in patients who were not tested by SOC MolDx, actionable variants were identified by cWGS in 54% (153/282). Conclusions: The WIDE study has shown that cWGS is feasible in routine clinical practice in a comprehensive cancer center setting, using tumor material obtained during routine procedures. Furthermore, cWGS showed added value by identifying one or more additional clinically actionable biomarkers in 54% of patients including patients who had not received SOC Moldx. These outcomes have led to the successful adoption of cWGS at the Netherlands Cancer Institute as part of routine care, which will further facilitate precision medicine for cancer patients.

Application of Full-Spectrum Rapid Clinical Genome Sequencing Improves Diagnostic Rate and Clinical Outcomes in Critically Ill Infants in the China Neonatal Genomes Project.

To determine the diagnostic and clinical utility of trio-rapid genome sequencing in critically ill infants. In this prospective study, samples from critically ill infants were analyzed using both proband-only clinical exome sequencing and trio-rapid genome sequencing (proband and biological parents). The study occurred between April 2019 and December 2019. Thirteen member hospitals of the China Neonatal Genomes Project spanning 10 provinces were involved. Critically ill infants (n = 202), from birth up until 13 months of life were enrolled based on eligibility criteria (e.g., CNS anomaly, complex congenital heart disease, evidence of metabolic disease, recurrent severe infection, suspected immune deficiency, and multiple malformations). None. Of the 202 participants, neuromuscular (45%), respiratory (22%), and immunologic/infectious (18%) were the most commonly observed phenotypes. The diagnostic yield of trio-rapid genome sequencing was higher than that of proband-only clinical exome sequencing (36.6% [95% CI, 30.1-43.7%] vs 20.3% [95% CI, 15.1-26.6%], respectively; p = 0.0004), and the average turnaround time for trio-rapid genome sequencing (median: 7 d) was faster than that of proband-only clinical exome sequencing (median: 20 d) (p < 2.2 × 10-16). The metagenomic analysis identified pathogenic or likely pathogenic microbes in six infants with symptoms of sepsis, and these results guided the antibiotic treatment strategy. Sixteen infants (21.6%) experienced a change in clinical management following trio-rapid genome sequencing diagnosis, and 24 infants (32.4%) were referred to a new subspecialist. Trio-rapid genome sequencing provided higher diagnostic yield in a shorter period of time in this cohort of critically ill infants compared with proband-only clinical exome sequencing. Precise and fast molecular diagnosis can alter medical management and positively impact patient outcomes.

Focused Revision: ACMG practice resource: Genetic evaluation of short stature

Focused Revision: ACMG practice resource: Genetic evaluation of short stature

Does the law require reinterpretation and return of revised genomic results?

Does the law require reinterpretation and return of revised genomic results?

Personalised virtual gene panels reduce interpretation workload and maintain diagnostic rates of proband-only clinical exome sequencing for rare disorders

PurposeThe increased adoption of genomic strategies in the clinic makes it imperative for diagnostic laboratories to improve the efficiency of variant interpretation. Clinical exome sequencing (CES) is becoming a valuable...

"I wish that there was more info": characterizing the uncertainty experienced by carriers of pathogenic ATM and/or CHEK2 variants.

Little is known about what uncertainties patients experience after being identified to carry a pathogenic variant in a moderate-risk cancer gene as a result of undergoing multigene panel testing for cancer susceptibility. Data regarding cancer risk estimates and effectiveness of risk management strategies for these variants continues to evolve, which has the potential to evoke uncertainty. Acknowledging uncertainty during pre- and post-test discussions is imperative to helping individuals to adapt to their results. A better understanding of this population's experience of uncertainty is needed to facilitate such discussions and is the aim of the current study. Semi-structured interviews (30-60min in length), informed by Han and colleagues' taxonomy of uncertainty in clinical genomic sequencing, were conducted to assess motivations to pursue genetic testing, areas of perceived uncertainty, and strategies for managing uncertainty among 20 carriers of pathogenic variants in two moderate-risk genes, ATM and CHEK2. We found that participants pursue genetic testing with the expectation that results will clarify cancer risks and approaches to management. Participants experience uncertainties aligning with Han's taxonomy relating to the ambiguity of specific cancer risk estimates and effectiveness of certain risk management strategies. These uncertainties influenced decisions around the uptake of risk management strategies, which were additionally impacted by clinicians' uncertainty towards such strategies. Participants employ a variety of uncertainty management approaches to cope with their anxieties. Clinicians may wish to use these findings to facilitate patient adaptation to the implications of multigene panel testing for cancer susceptibility during both pre- and post-test counseling sessions.

Using structural analysis to clarify the impact of single nucleotide variants in neurexin/neuroligin revealed in clinical genomic sequencing

The synapse is a highly specialized and dynamic structure, which is involved in regulating neurotransmission. Nerve cell adhesion molecule is a kind of transmembrane protein that mediates the interaction between cells and cells, cells and extracellular matrix, and plays a role in cell recognition, metastasis, and transmembrane signal transduction. Among nerve cell adhesion molecules, Neurexins (NRXNs) and Neuroligins (NLGNs) have been focused due to the relation with autism and other neuropsychiatric diseases. The previous research discovered numerous variants in NRXNs and NLGNs reported in neurodevelopmental disorders by genomic sequencing. However, structural variants in synaptic molecules caused by genome variants still prevent us from understanding the molecular mechanism of diseases. Thus, we sought to conduct a comprehensive risk assessment of the known NRXN and NLGN gene variants by protein structure analysis. In this study, we analyzed the structural properties of the NRXN/NLGN complex by calculating free energy in residue scanning, in combination with existing risk evaluation tools to focus on candidate missense mutations. Our calculations show that five candidate missense mutations in NLGNs can reduce the stability of NLGNs and even prevent the formation of NRXN/NLGN complexes, namely R87W, R204H, R437H, R437C and R583W. In addition, we found that the affinity of the amino acid substitution (Leu593Phe) (ΔΔG (affinity)) changes the affinity of the NLGN dimer. Overall, we have identified important potential pathological variants that provide clues to biomarkers. Communicated by Ramaswamy H. Sarma

EP290 - A case series of challenging molecular diagnoses identified by clinical whole genome sequencing

eP290 - A case series of challenging molecular diagnoses identified by clinical whole genome sequencing

A Functional Taxonomy of Tumor Suppression in Oncogenic KRAS-Driven Lung Cancer.

Cancer genotyping has identified a large number of putative tumor suppressor genes. Carcinogenesis is a multistep process, but the importance and specific roles of many of these genes during tumor initiation, growth, and progression remain unknown. Here we use a multiplexed mouse model of oncogenic KRAS-driven lung cancer to quantify the impact of 48 known and putative tumor suppressor genes on diverse aspects of carcinogenesis at an unprecedented scale and resolution. We uncover many previously understudied functional tumor suppressors that constrain cancer in vivo. Inactivation of some genes substantially increased growth, whereas the inactivation of others increases tumor initiation and/or the emergence of exceptionally large tumors. These functional in vivo analyses revealed an unexpectedly complex landscape of tumor suppression that has implications for understanding cancer evolution, interpreting clinical cancer genome sequencing data, and directing approaches to limit tumor initiation and progression. SIGNIFICANCE: Our high-throughput and high-resolution analysis of tumor suppression uncovered novel genetic determinants of oncogenic KRAS-driven lung cancer initiation, overall growth, and exceptional growth. This taxonomy is consistent with changing constraints during the life history of cancer and highlights the value of quantitative in vivo genetic analyses in autochthonous cancer models.This article is highlighted in the In This Issue feature, p. 1601.

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

Through improving diagnostics and prognostics genomic sequencing promises to significantly impact clinical decisions for children with critical cardiac disease. Little is known about how families of children with critical cardiac disease perceive the impact of genomic sequencing on clinical care choices. Qualitative interview study. A high-volume, tertiary pediatric heart center. Families of children with critical cardiac disease. None. Thematic analysis of interview response content. Thirty-five families were interviewed. Three themes emerged: 1) benefits versus challenges of having genomic sequencing results, and 2) fears of clinical applications of genomic sequencing, and 3) nonclinical fears related to genomic sequencing. Participants struggled with perceived uses of genomic sequencing-derived knowledge. They described comfort in foreknowledge of their child's likely disease course but articulated significant apprehension around participating in care decisions with limited knowledge of genomic sequencing, genomic sequencing uses to inform clinical resource rationing decisions, and genomic sequencing uses by third parties impacting financial pressures families experience caring for a child with critical cardiac disease. Families' perceptions of genomic sequencing uses in critical cardiac disease appear to strain their overall trust in the health system. Erosion of trust is concerning because the potential of genomic sequencing in critical cardiac disease will be unrealized if families are unwilling to undergo genomic sequencing, let alone to participate in the ongoing research needed to link genomic sequencing variants to clinical outcomes. Our findings may have implications for genomic sequencing use in children with other critical, high-acuity diseases.

Heterozygous KCNH2 variant phenotyping using Flp-In HEK293 and high-throughput automated patch clamp electrophysiology.

KCNH2 is one of the 59 medically actionable genes recommended by the American College of Medical Genetics for reporting of incidental findings from clinical genomic sequencing. However, half of the reported KCNH2 variants in the ClinVar database are classified as variants of uncertain significance. In the absence of strong clinical phenotypes, there is a need for functional phenotyping to help decipher the significance of variants identified incidentally. Here, we report detailed methods for assessing the molecular phenotype of any KCNH2 missense variant. The key components of the assay include quick and cost-effective generation of a bi-cistronic vector to co-express Wild-type (WT) and any KCNH2 variant allele, generation of stable Flp-In HEK293 cell lines and high-throughput automated patch clamp electrophysiology analysis of channel function. Stable cell lines take 3–4 weeks to produce and can be generated in bulk, which will then allow up to 30 variants to be phenotyped per week after 48 h of channel expression. This high-throughput functional genomics assay will enable a much more rapid assessment of the extent of loss of function of any KCNH2 variant.

A Pan-Cancer Study of Somatic TERT Promoter Mutations and Amplification in 30,773 Tumors Profiled by Clinical Genomic Sequencing

TERT gene promoter mutations are known in multiple cancer types. Other TERT alterations remain poorly characterized. Sequencing data from 30,773 tumors analyzed by a hybridization capture next-generation sequencing assay (Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets) were analyzed for the presence of TERT alterations. Promoter rearrangements (500 bases upstream of the transcriptional start site), hypermethylation (n = 57), and gene expression (n = 155) were evaluated for a subset of cases. Mutually exclusive and recurrent promoter mutations were identified at three hot spots upstream of the transcriptional start site in 11.3% of cases (-124: 74%; -146: 24%; and -138: <2%). Mutually exclusive amplification events were identified in another 2.3% of cases, whereas mutually exclusive rearrangements proximal to the TERT gene were seen in 24 cases. The highest incidence of TERT promoter mutations was seen in cutaneous melanoma (82%), whereas amplification events significantly outnumbered promoter mutations in well-differentiated/dedifferentiated liposarcoma (14.1% versus 2.4%) and adrenocortical carcinoma (13.6% versus 4.5%). Gene expression analysis suggests that the highest levels of gene expression are seen in cases with amplifications and rearrangements. Hypermethylation eventsupstream of the TERT coding sequence were not mutually exclusive with known pathogenic alterations. Studies aimed at defining the prevalence and prognostic impact of TERT alterations should incorporateother pathogenic TERT alterations as these may impact telomerase function.

Abstract 16066: Genomic Autopsy of 103 Sudden Deaths in the Young Reveals the Importance of Cardiomyopathy Genes and Non-Mendelian Risk

Introduction: Genetic testing after sudden death in the young can identify pathogenic cardiac gene variants. Hypothesis: Genomic methods, coupled with phenotype evaluation, reveal non-Mendalian risks. Methods: We conducted clinical analysis and whole genome sequencing on 103 decedents aged 1-40 (mean age at death 23.7 years) accrued prospectively from 2015 to 2019 across 22 states. Postmortem pathological findings were classified as: known cardiac disorders, findings of uncertain significance (FUS), or sudden unexplained death (SUD, indicating no postmortem pathological diagnosis). Parental DNA and clinical data were obtained where possible. Variants were classified by an independent clinical genetic laboratory. Results: Among the 103 decedents, 34 had a postmortem clinical diagnosis, 23 had FUS, and 46 were classified as SUD. Pathogenic/likely pathogenic (P/LP) variants in arrhythmia or cardiomyopathy genes were identified in 17 (16.5%) decedents. The distribution of P/LP variants was not associated with age at death (OR 1.01 [0.97, 1.05], p=0.54); however, a multivariable analysis including decedent phenotype, ancestry and sex demonstrated that younger decedents had a higher burden of curated P/LP/VUS variants (effect size -1.5, p=0.0019). DNA from 31 parent-decedent trios and 14 parent-decedent dyads revealed 9 transmitted P/LP variants and 1 de novo P/LP variant. More than half of parents transmitting a P/LP variant (5/9) did not have clinical findings associated with the genotype. Conclusions: Whole genome sequencing effectively revealed P/LP variants in cases of sudden death in the young, implicating both arrhythmia and cardiomyopathy genes. In addition, both genotype and phenotype analyses suggest additional non-Mendelian risk mechanisms.

A decision aid for additional findings in genomic sequencing: Development and pilot testing

ObjectiveTo describe the development of a web-based, patient-facing decision aid to support patients and research participants to make an informed, values-based decision about whether to receive additional results from genomic sequencing. MethodsWe developed the decision aid following the multi-step process described in the International Patient Decision Aids Standards. This utilized literature review, focus groups, and alpha testing with research participants undergoing clinical genomic sequencing. ResultsThe decision aid, the Optional Results Choice Aid (ORCA), includes a seven-question “values clarification exercise,” illustrative patient quotes, and summative guidance for the user. The decision aid was found to be highly readable, acceptable and relevant in alpha testing. ConclusionWe developed a decision aid to support informed, values-based decision making for patients and research participants considering whether to receive additional results from genomic sequencing. ORCA is being implemented in the NHGRI-funded Cancer Health Assessment Reaching Many (CHARM) study, where we are measuring informed values-choice congruence. Practice implicationsORCA was designed to support patients and research participants to make an informed, values-based decision about whether to receive additional results from genomic sequencing.

Expanding Use of Clinical Genome Sequencing and the Need for More Data on Implementation

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Family communication about genomic sequencing: A qualitative study with cancer patients and relatives

ObjectiveThis study explored family communication about undertaking genomic sequencing, and intentions to communicate pertinent heritable results to family members. MethodsSemi-structured interviews were conducted with cancer patients (n = 53) and their relatives (n = 20) who underwent germline genome sequencing or molecular tumor testing. Interviews were audio-recorded, transcribed and analyzed using thematic analysis. ResultsKey themes relevant to family communication about undertaking sequencing included: perceiving family member interest, delaying discussion until results were received, having shared capacity to understand and cope, and having open communication in the family. Intended communication subsequent to receiving results was affected by: disease severity, risk management options, degree of closeness in the family, sense of responsibility, and potential adverse impacts on family. Resource and support needs varied based on the complexity of test results, health professionals’ availability, and disease severity. Unique subthemes were identified for specific subgroups. ConclusionCurrent findings support the need to assess the impact and resource needs specific to each clinical application of genomic sequencing. Practice implicationsIncreasingly sophisticated and complex clinical genomic sequencing warrants development of family-centered interventions and resources to facilitate preference-sensitive communication about genomic sequencing, including disseminating relevant information to family members.

Engaging community stakeholders in research on best practices for clinical genomic sequencing.

Aim:Maximizing the utility and equity of genomic sequencing integration in clinical care requires engaging patients, their families, and communities. The NCGENES 2 study explores the impact of engagement between clinicians and caregivers of children with undiagnosed conditions in the context of a diagnostic genomic sequencing study.Methods:A Community Consult Team (CCT) of diverse parents and advocates for children with genetic and/or neurodevelopmental conditions was formed.Results:Early and consistent engagement with the CCT resulted in adaptations to study protocol and materials relevant to this unique study population.Discussion:This study demonstrates valuable contributions of community stakeholders to inform the implementation of translational genomics research for diverse participants.

Old Challenges or New Issues? Genetic Health Professionals’ Experiences Obtaining Informed Consent in Diagnostic Genomic Sequencing

Background While integrating genomic sequencing into clinical care carries clear medical benefits, it also raises difficult ethical questions. Compared to traditional sequencing technologies, genomic sequencing and analysis is more likely to identify unsolicited findings (UF) and variants that cannot be classified as benign or disease-causing (variants of uncertain significance; VUS). UF and VUS pose new challenges for genetic health professionals (GHPs) who are obtaining informed consent for genomic sequencing from patients. Methods We conducted semi-structured interviews with 31 GHPs across Europe, Australia and Canada to identify some of these challenges. Results Our results show that GHPs find it difficult to prepare patients to receive results because a vast amount of information is required to fully inform patients about VUS and UF. GHPs also struggle to engage patients – many of whom may be focused on ending their ‘diagnostic odyssey’ – in the informed consent process in a meaningful way. Thus, some questioned how ‘informed’ patients actually are when they agree to undergo clinical genomic sequencing. Conclusions These findings suggest a tension remains between sufficient information provision at the risk of overwhelming the patient and imparting less information at the risk of uninformed decision-making. We suggest that a shift away from ‘fully informed consent’ toward an approach aimed at realizing, as far as possible, the underlying goals that informed consent is meant to promote.

PCV3 Global Landscape of Clinical Genomic Sequencing: Who, Where, and How?

PCV3 Global Landscape of Clinical Genomic Sequencing: Who, Where, and How?

Clinical Genomic Sequencing Reports in Electronic Health Record Systems Based on International Standards: Implementation Study.

BackgroundTo implement standardized machine-processable clinical sequencing reports in an electronic health record (EHR) system, the International Organization for Standardization Technical Specification (ISO/TS) 20428 international standard was proposed for a structured template. However, there are no standard implementation guidelines for data items from the proposed standard at the clinical site and no guidelines or references for implementing gene sequencing data results for clinical use. This is a significant challenge for implementation and application of these standards at individual sites.ObjectiveThis study examines the field utilization of genetic test reports by designing the Health Level 7 (HL7) Fast Healthcare Interoperability Resources (FHIR) for genomic data elements based on the ISO/TS 20428 standard published as the standard for genomic test reports. The goal of this pilot is to facilitate the reporting and viewing of genomic data for clinical applications. FHIR Genomics resources predominantly focus on transmitting or representing sequencing data, which is of less clinical value.MethodsIn this study, we describe the practical implementation of ISO/TS 20428 using HL7 FHIR Genomics implementation guidance to efficiently deliver the required genomic sequencing results to clinicians through an EHR system.ResultsWe successfully administered a structured genomic sequencing report in a tertiary hospital in Korea based on international standards. In total, 90 FHIR resources were used. Among 41 resources for the required fields, 26 were reused and 15 were extended. For the optional fields, 28 were reused and 21 were extended.ConclusionsTo share and apply genomic sequencing data in both clinical practice and translational research, it is essential to identify the applicability of the standard-based information system in a practical setting. This prototyping work shows that reporting data from clinical genomics sequencing can be effectively implemented into an EHR system using the existing ISO/TS 20428 standard and FHIR resources.