Re-analysis of genomic data: An overview of the mechanisms and complexities of clinical adoption

Appropriate time interval to update ambiguous genetic diagnosis in inherited arrhythmogenic syndromes

Genetic analysis identified the cause of the disease in inherited arrhythmogenic syndromes. A clinically actionable genetic diagnosis requires an accurate interpretation following the current guidelines. Practically half of the genetic diagnoses remain inconclusive due to the identification of variants of uncertain significance. An update can help shed light on uncertain results. No specific time frame has been set for updating an ambiguous diagnosis. We carried out an analysis of the available reclassification/reinterpretation data concerning genetic diagnosis in inherited arrhythmogenic syndromes. We aim to determine an appropriate interval for updating a conclusive classification. Genetic diagnoses achieved without following current guidelines should be updated immediately. An ambiguous result obtained following the current guidelines should be updated no more than 5 years after the first analysis. There are still questions to be resolved regarding the legal responsibility or who should assume the economic cost of updating a genetic diagnosis.

Implementation of a Kidney Genetic Service Into the Diagnostic Pathway for Patients With Chronic Kidney Disease in Canada

Introduction

Genetic kidney disease (GKD) accounts for 10% to 20% of chronic kidney disease (CKD). Genetic testing using gene panel or targeted exome sequencing (ES) can confirm GKD; however, integration into clinical practice has been hampered by small studies, selective populations, and data predominately derived from research settings. Using prespecified clinical referral criteria and a diagnostic pipeline, we performed a prospective cohort study describing diagnostic efficacy and clinical utility of genetic assessment in patients with CKD.

Methods

We analyzed a prospective cohort of 300 participants (256 families) referred to a kidney genetics clinic, between March 2020 and March 2024. Testing strategies included gene panels, and if negative or unsuitable, targeted ES analysis. Testing was performed for the detection of variants in genes known to cause CKD.

Results

We identified a causative variant in 33% of families (85/256). Diagnostic yield increased from 23% (n = 70/300) from gene panel alone, to 34% (n = 103/300) with comprehensive testing. The median time from first diagnosis of CKD to genetic assessment was long at 10.4 years. Following genetic assessment, the median time to receive a positive genetic result was 2.9 months. Multiple levels of clinical utility were recorded in patients receiving a genetic diagnosis, varying across CKD subtype.

Conclusion

Instituting referral guidelines and a standardized testing algorithm established a genetic diagnosis in one-third of participants, providing insight into the viability of integrating genetic assessment in the CKD diagnostic pathway. Considering the potential for clinical utility, strategies to reduce the time from CKD diagnosis to genetics assessment are needed.

A guide to gene-disease relationships in nephrology

The use of next-generation sequencing technologies such as exome and genome sequencing in research and clinical care has transformed our understanding of the molecular architecture of genetic kidney diseases. Although the capability to identify and rigorously assess genetic variants and their relationship to disease has advanced considerably in the past decade, the curation of clinically relevant relationships between genes and specific phenotypes has received less attention, despite it underpinning accurate interpretation of genomic tests. Here, we discuss the need to accurately define gene-disease relationships in nephrology and provide a framework for appraising genetic and experimental evidence critically. We describe existing international programmes that provide expert curation of gene-disease relationships and discuss sources of discrepancy as well as efforts at harmonization. Further, we highlight the need for alignment of disease and phenotype terminology to ensure robust and reproducible curation of knowledge. These collective efforts to support evidence-based translation of genomic sequencing into practice across clinical, diagnostic and research settings are crucial for delivering the promise of precision medicine in nephrology, providing more patients with timely diagnoses, accurate prognostic information and access to targeted treatments.

The Australian Genomics Mitochondrial Flagship: A national program delivering mitochondrial diagnoses

PURPOSE

Families living with mitochondrial diseases (MD) often endure prolonged diagnostic journeys and invasive testing, yet many remain without a molecular diagnosis. The Australian Genomics Mitochondrial Flagship, comprising clinicians, diagnostic, and research scientists, conducted a prospective national study to identify the diagnostic utility of singleton genomic sequencing using blood samples.

METHODS

A total of 140 children and adults living with suspected MD were recruited using modified Nijmegen criteria (MNC) and randomized to either exome + mitochondrial DNA (mtDNA) sequencing or genome sequencing.

RESULTS

Diagnostic yield was 55% (n = 77) with variants in nuclear (n = 37) and mtDNA (n = 18) MD genes, as well as phenocopy genes (n = 22). A nuclear gene etiology was identified in 77% of diagnoses, irrespective of disease onset. Diagnostic rates were higher in pediatric-onset (71%) than adult-onset (31%) cases and comparable in children with non-European (78%) vs European (67%) ancestry. For children, higher MNC scores correlated with increased diagnostic yield and fewer diagnoses in phenocopy genes. Additionally, 3 adult patients had a mtDNA deletion discovered in skeletal muscle that was not initially identified in blood.

CONCLUSION

Genomic sequencing from blood can simplify the diagnostic pathway for individuals living with suspected MD, especially those with childhood onset diseases and high MNC scores.

CNVizard-a lightweight streamlit application for an interactive analysis of copy number variants

BACKGROUND

Methods to call, analyze and visualize copy number variations (CNVs) from massive parallel sequencing data have been widely adopted in clinical practice and genetic research. To enable a streamlined analysis of CNV data, comprehensive annotations and good visualizations are indispensable. The ability to detect single exon CNVs is another important feature for genetic testing. Nonetheless, most available open-source tools come with limitations in at least one of these areas. One additional drawback is that available tools deliver data in an unstructured and static format which requires subsequent visualization and formatting efforts.

RESULTS

Here we present CNVizard, an interactive Streamlit app allowing a comprehensive visualization of CNVkit data. Furthermore, combining CNVizard with the CNVand pipeline allows the annotation and visualization of CNV or SV VCF files from any CNV caller.

CONCLUSION

CNVizard, in combination with CNVand, enables the comprehensive and streamlined analysis of short- and long-read sequencing data and provide an intuitive webapp-like experience enabling an interactive visualization of CNV data.

Fetal whole genome sequencing as a clinical diagnostic tool: Advantages, limitations and pitfalls

Genome-wide sequencing, which includes exome sequencing and genome sequencing, has revolutionized the diagnostics of genetic disorders in both postnatal and prenatal settings. Compared to exome sequencing, genome sequencing enables the detection of many additional types of genomic variants, although this depends on the bioinformatics pipelines used. Variant classification might vary among laboratories. In the prenatal setting, variant classification may change if new fetal phenotypic features emerge as the pregnancy progresses. There is still a need to evaluate the incremental diagnostic yield of genome sequencing compared to exome sequencing in the prenatal setting. This article reviews the advantages and limitations of genome sequencing, with an emphasis on fetal diagnostics.

Actionable Variants of Unknown Significance in Inherited Arrhythmogenic Syndromes: A Further Step Forward in Genetic Diagnosis

Background/Objectives: Inherited arrhythmogenic syndromes comprise a heterogenic group of genetic entities that lead to malignant arrhythmias and sudden cardiac death. Genetic testing has become crucial to understand the disease etiology and allow for the early identification of relatives at risk; however, it requires an accurate interpretation of the data to achieve a clinically actionable outcome. This is particularly challenging for the large number of rare variants obtained by current high-throughput techniques, which are mostly classified as of unknown significance. Methods: In this work, we present a new algorithm for the genetic interpretation of the remaining rare variants in order to shed light on their potential clinical implications and reduce the burden of unknown significance. Results: Our study illustrates the potential utility of our individualized comprehensive stepwise analyses focused on the rare variants associated with IAS, which are currently classified as ambiguous, to further determine their trends towards pathogenicity or benign traits. Conclusions: We advocate for personalized disease-focused population frequency data and family segregation analyses for all rare variants that remain ambiguous to further clarify their role. The current ambiguity should not influence medical decisions, but a potential deleterious role would suggest a closer clinical follow-up and frequent genetic data review for a more personalized clinical approach.

Reanalysis of genomic data in rare disease: current practice and attitudes among Australian clinical and laboratory genetics services

Reanalyzing stored genomic data over time is highly effective in increasing diagnostic yield in rare disease. Automation holds the promise of delivering the benefits of reanalysis at scale. Our study aimed to understand current reanalysis practices among Australian clinical and laboratory genetics services and explore attitudes towards large-scale automated re-analysis. We collected audit data regarding testing and reanalysis volumes, policies and procedures from all Australian diagnostic laboratories providing rare disease genomic testing. A genetic health professionals' survey explored current practices, barriers to reanalysis, preferences and attitudes towards automation. Between 2018 and 2021, Australian diagnostic laboratories performed over 25,000 new genomic tests and 950 reanalyses, predominantly in response to clinician requests. Laboratory and clinical genetic health professionals (N = 134) identified workforce capacity as the principal barrier to reanalysis. No specific laboratory or clinical guidelines for genomic data reanalysis or policies were identified nationally. Perceptions of acceptability and feasibility of automating reanalysis were positive, with professionals emphasizing clinical and workflow benefits. In conclusion, there is a large and rapidly growing unmet need for reanalysis of existing genomic data. Beyond developing scalable automated reanalysis pipelines, leadership and policy are needed to successfully transform service delivery models and maximize clinical benefit.

It Is in Our DNA: Bringing Electronic Health Records and Genomic Data Together for Precision Medicine

Health care is at a turning point. We are shifting from protocolized medicine to precision medicine, and digital health systems are facilitating this shift. By providing clinicians with detailed information for each patient and analytic support for decision-making at the point of care, digital health technologies are enabling a new era of precision medicine. Genomic data also provide clinicians with information that can improve the accuracy and timeliness of diagnosis, optimize prescribing, and target risk reduction strategies, all of which are key elements for precision medicine. However, genomic data are predominantly seen as diagnostic information and are not routinely integrated into the clinical workflows of electronic medical records. The use of genomic data holds significant potential for precision medicine; however, as genomic data are fundamentally different from the information collected during routine practice, special considerations are needed to use this information in a digital health setting. This paper outlines the potential of genomic data integration with electronic records, and how these data can enable precision medicine.

Systematic reanalysis of genomic data by diagnostic laboratories: a scoping review of ethical, economic, legal and (psycho)social implications

With the introduction of Next Generation Sequencing (NGS) techniques increasing numbers of disease-associated variants are being identified. This ongoing progress might lead to diagnoses in formerly undiagnosed patients and novel insights in already solved cases. Therefore, many studies suggest introducing systematic reanalysis of NGS data in routine diagnostics. Introduction will, however, also have ethical, economic, legal and (psycho)social (ELSI) implications that Genetic Health Professionals (GHPs) from laboratories should consider before possible implementation of systematic reanalysis. To get a first impression we performed a scoping literature review. Our findings show that for the vast majority of included articles ELSI aspects were not mentioned as such. However, often these issues were raised implicitly. In total, we identified nine ELSI aspects, such as (perceived) professional responsibilities, implications for consent and cost-effectiveness. The identified ELSI aspects brought forward necessary trade-offs for GHPs to consciously take into account when considering responsible implementation of systematic reanalysis of NGS data in routine diagnostics, balancing the various strains on their laboratories and personnel while creating optimal results for new and former patients. Some important aspects are not well explored yet. For example, our study shows GHPs see the values of systematic reanalysis but also experience barriers, often mentioned as being practical or financial only, but in fact also being ethical or psychosocial. Engagement of these GHPs in further research on ELSI aspects is important for sustainable implementation.

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.

Reclassification of Genetic Testing Results: A Case Report Demonstrating the Need for Structured Re-Evaluation of Genetic Findings

Rationale

Alport Syndrome (AS) is a progressive genetic condition characterized by chronic kidney disease (CKD), hearing loss, and eye abnormalities. It is caused by mutations in the genes COL4A3, COL4A4, and COL4A5. Heterozygous mutations in COL4A4 and COL4A3 cause autosomal dominant Alport Syndrome (ADAS), and a spectrum of phenotypes ranging from asymptomatic hematuria to CKD, with variable extra-renal features. In the past, heterozygous mutations in these genes were thought to be benign, however recent studies show that about 30% of patients can progress to CKD, and 15% can progress to end stage kidney disease (ESKD).

Presenting Concerns

We present a case of a woman who was noted to have microscopic hematuria pre-living kidney donation. Genetic testing revealed a heterozygous variant of uncertain significance (VUS) in the COL4A4 gene. VUSs are medically nonactionable findings and data show that VUSs can be detected in 41% of all patients who undergo clinical genetic testing. VUSs frustrate clinicians and patients alike. Although they cannot be used in medical decision-making, data suggest that reanalysis can result in the reclassification of a VUS over time.

Diagnosis

Post-donation, the index patient had a higher than anticipated rise in serum creatinine, raising a concern for possible intrinsic kidney disease. Kidney biopsy was deemed high risk in the setting of a unilateral kidney thereby limiting possible diagnostic intervention to determine the cause of disease.

Intervention

Re-evaluation of prior genetic testing results and reassessment of the previously identified VUS in COL4A4 was performed 5-years post-donation. These analyses, along with the addition of new phenotypic data and extended pedigree data, resulted in the reclassification of the previously identified VUS to a likely pathogenic variant.

Outcomes

This case demonstrates the importance of structured, periodic re-evaluation of genetic testing results. With the ever-changing landscape of genetics in medicine, the interpretation of a VUS can be dynamic and therefore warrant caution in living kidney donor evaluations. Studies have shown that about 10% of VUSs can be upgraded to a pathogenic classification after an 18- to 36-month interval. Structured re-evaluation of genomic testing results has not yet been integrated into clinical practice and poses a unique challenge in living kidney donation.

Novel findings

This case report highlights the variability of the ADAS phenotype caused by pathogenic heterozygous variants in the type 4 collagen genes. It supports the nomenclature change from a benign hematuria phenotype to ADAS, particularly when additional risk factors such as proteinuria, focal segmental glomerulosclerosis or glomerular basement membrane changes on kidney biopsy are present, or as in this case, evidence of disease in other family members.

Clinically significant changes in genes and variants associated with epilepsy over time: implications for re-analysis

Despite the significant advances in understanding the genetic architecture of epilepsy, many patients do not receive a molecular diagnosis after genomic testing. Re-analysing existing genomic data has emerged as a potent method to increase diagnostic yields-providing the benefits of genomic-enabled medicine to more individuals afflicted with a range of different conditions. The primary drivers for these new diagnoses are the discovery of novel gene-disease and variants-disease relationships; however, most decisions to trigger re-analysis are based on the passage of time rather than the accumulation of new knowledge. To explore how our understanding of a specific condition changes and how this impacts re-analysis of genomic data from epilepsy patients, we developed Vigelint. This approach combines the information from PanelApp and ClinVar to characterise how the clinically relevant genes and causative variants available to laboratories change over time, and this approach to five clinical-grade epilepsy panels. Applying the Vigelint pipeline to these panels revealed highly variable patterns in new, clinically relevant knowledge becoming publicly available. This variability indicates that a more dynamic approach to re-analysis may benefit the diagnosis and treatment of epilepsy patients. Moreover, this work suggests that Vigelint can provide empirical data to guide more nuanced, condition-specific approaches to re-analysis.

Next-generation sequencing and comprehensive data reassessment in 263 adult patients with neuromuscular disorders: insights into the gray zone of molecular diagnoses

BACKGROUND

Neuromuscular disorders (NMDs) are heterogeneous conditions with a considerable fraction attributed to monogenic defects. Despite the advancements in genomic medicine, many patients remain without a diagnosis. Here, we investigate whether a comprehensive reassessment strategy improves the diagnostic outcomes.

METHODS

We analyzed 263 patients with NMD phenotypes that underwent diagnostic exome or genome sequencing at our tertiary referral center between 2015 and 2023. We applied a comprehensive reassessment encompassing variant reclassification, re-phenotyping and NGS data reanalysis. Multivariable logistic regression was performed to identify predictive factors associated with a molecular diagnosis.

RESULTS

Initially, a molecular diagnosis was identified in 53 cases (20%), while an additional 23 (9%) had findings of uncertain significance. Following comprehensive reassessment, the diagnostic yield increased to 23%, revealing 44 distinct monogenic etiologies. Reasons for newly obtained molecular diagnoses were variant reclassifications in 7 and NGS data reanalysis in 3 cases including one recently described disease-gene association (DNAJB4). Male sex reduced the odds of receiving a molecular diagnosis (OR 0.42; 95%CI 0.21-0.82), while a positive family history (OR 5.46; 95%CI 2.60-11.76) and a myopathy phenotype (OR 2.72; 95%CI 1.11-7.14) increased the likelihood. 7% were resolved through targeted genetic testing or classified as acquired etiologies.

CONCLUSION

Our findings reinforce the use of NGS in NMDs of suspected monogenic origin. We show that a comprehensive reassessment enhances diagnostic accuracy. However, one needs to be aware that genetic diagnoses are often made with uncertainty and can even be downgraded based on new evidence.

Relevance of next generation sequencing (NGS) data re-analysis in the diagnosis of monogenic diseases leading to organ failure

BACKGROUND

In 2018, our center started a program to offer genetic diagnosis to patients with kidney and liver monogenic rare conditions, potentially eligible for organ transplantation. We exploited a clinical exome sequencing approach, followed by analyses of in silico gene panels tailored to clinical suspicions, obtaining detection rates in line with what reported in literature. However, a percentage of patients remains without a definitive genetic diagnosis. This work aims to evaluate the utility of NGS data re-analysis for those patients with an inconclusive or negative genetic test at the time of first analysis considering that (i) the advance of alignment and variant calling processes progressively improve the detection rate, limiting false positives and false negatives; (ii) gene panels are periodically updated and (iii) variant annotation may change over time.

METHODS

114 patients, recruited between 2018 and 2020, with an inconclusive or negative NGS report at the time of first analysis, were included in the study. Re-alignment and variant calling of previously generated sequencing raw data were performed using the GenomSys Variant Analyzer software.

RESULTS

21 previously not reported potentially causative variants were identified in 20 patients. In most cases (n = 19), causal variants were retrieved out of the re-classification from likely benign to variants of unknown significance (VUS). In one case, the variant was included because of inclusion in the analysis of a newly disease-associated gene, not present in the original gene panel, and in another one due to the improved data alignment process. Whenever possible, variants were validated with Sanger sequencing and family segregation studies. As of now, 16 out of 20 patients have been analyzed and variants confirmed in 8 patients. Specifically, in two pediatric patients, causative variants were de novo mutations while in the others, the variant was present also in other affected relatives. In the remaining patients, variants were present also in non-affected parents, raising questions on their re-classification.

CONCLUSIONS

Overall, these data indicate that periodic and systematic re-analysis of negative or inconclusive NGS data reports can lead to new variant identification or reclassification in a small but significant proportion of cases, with benefits for patients' management.

Is there a duty to routinely reinterpret genomic variant classifications?

Multiple studies show that periodic reanalysis of genomic test results held by clinical laboratories delivers significant increases in overall diagnostic yield. However, while there is a widespread consensus that implementing routine reanalysis procedures is highly desirable, there is an equally widespread understanding that routine reanalysis of individual patient results is not presently feasible to perform for all patients. Instead, researchers, geneticists and ethicists are beginning to turn their attention to one part of reanalysis-reinterpretation of previously classified variants-as a means of achieving similar ends to large-scale individual reanalysis but in a more sustainable manner. This has led some to ask whether the responsible implementation of genomics in healthcare requires that diagnostic laboratories routinely reinterpret their genomic variant classifications and reissue patient reports in the case of materially relevant changes. In this paper, we set out the nature and scope of any such obligation, and analyse some of the main ethical considerations pertaining to a putative duty to reinterpret. We discern and assess three potential outcomes of reinterpretation-upgrades, downgrades and regrades-in light of ongoing duties of care, systemic error risks and diagnostic equity. We argue against the existence of any general duty to reinterpret genomic variant classifications, yet we contend that a suitably restricted duty to reinterpret ought to be recognised, and that the responsible implementation of genomics into healthcare must take this into account.

International Undiagnosed Diseases Programs (UDPs): components and outcomes

Over the last 15 years, Undiagnosed Diseases Programs have emerged to address the significant number of individuals with suspected but undiagnosed rare genetic diseases, integrating research and clinical care to optimize diagnostic outcomes. This narrative review summarizes the published literature surrounding Undiagnosed Diseases Programs worldwide, including thirteen studies that evaluate outcomes and two commentary papers. Commonalities in the diagnostic and research process of Undiagnosed Diseases Programs are explored through an appraisal of available literature. This exploration allowed for an assessment of the strengths and limitations of each of the six common steps, namely enrollment, comprehensive clinical phenotyping, research diagnostics, data sharing and matchmaking, results, and follow-up. Current literature highlights the potential utility of Undiagnosed Diseases Programs in research diagnostics. Since participants have often had extensive previous genetic studies, research pipelines allow for diagnostic approaches beyond exome or whole genome sequencing, through reanalysis using research-grade bioinformatics tools and multi-omics technologies. The overall diagnostic yield is presented by study, since different selection criteria at enrollment and reporting processes make comparisons challenging and not particularly informative. Nonetheless, diagnostic yield in an undiagnosed cohort reflects the potential of an Undiagnosed Diseases Program. Further comparisons and exploration of the outcomes of Undiagnosed Diseases Programs worldwide will allow for the development and improvement of the diagnostic and research process and in turn improve the value and utility of an Undiagnosed Diseases Program.

Multidisciplinary molecular consultation increases the diagnosis of pediatric epileptic encephalopathy and neurodevelopmental disorders

BACKGROUND

Epilepsy (EP) is a common neurological disease in which 70-80% are thought to have a genetic cause. In patients with epilepsy, neurodevelopmental delay (NDD) was prevalent. Next generation of sequencing has been widely used in diagnosing EP/NDD. However, the diagnostic yield remains to be 40%-50%. Many reanalysis pipelines and software have been developed for automated reanalysis and decision making for the diseases. Nevertheless, it is a highly challenging task for smaller genetic centers or a routine pediatric practice. To address the clinical and genetic "diagnostic odyssey," we organized a Multidisciplinary Molecular Consultation (MMC) team for molecular consultation for 202 children with EP/NDD patients referred by lower level hospitals.

METHODS

All the patients had undergone an aligned and sequential consultations and discussions by a "triple reanalysis" procedure by clinical, genetic specialists, and researchers.

RESULTS

Among the 202 cases for MMC, we totally identified 47 cases (23%) harboring causative variants in 24 genes and 15 chromosomal regions after the MMC. In the 15 cases with positive CNVs, 3 cases harbor the deletions or duplications in 16p11.2, and 2 cases for 1p36. The bioinformatical reanalysis revealed 47 positive cases, in which 12 (26%) were reported to be negative, VUS or incorrectly positive in pre-MMC reports. Additionally, among 87 cases with negative cases, 4 (5%) were reported to be positive in pre-MMC reports.

CONCLUSION

We established a workflow allowing for a "one-stop" collaborative assessments by experts of multiple fields and helps for correct the diagnosis of cases with falsenegative and -positive and VUS genetic reports and may have significant influences for intervention, prevention and genetic counseling of pediatric epilepsy and neurodevelopmental disorders.

The clinical utility and costs of whole-genome sequencing to detect cancer susceptibility variants-a multi-site prospective cohort study

BACKGROUND

Many families and individuals do not meet criteria for a known hereditary cancer syndrome but display unusual clusters of cancers. These families may carry pathogenic variants in cancer predisposition genes and be at higher risk for developing cancer.

METHODS

This multi-centre prospective study recruited 195 cancer-affected participants suspected to have a hereditary cancer syndrome for whom previous clinical targeted genetic testing was either not informative or not available. To identify pathogenic disease-causing variants explaining participant presentation, germline whole-genome sequencing (WGS) and a comprehensive cancer virtual gene panel analysis were undertaken.

RESULTS

Pathogenic variants consistent with the presenting cancer(s) were identified in 5.1% (10/195) of participants and pathogenic variants considered secondary findings with potential risk management implications were identified in another 9.7% (19/195) of participants. Health economic analysis estimated the marginal cost per case with an actionable variant was significantly lower for upfront WGS with virtual panel ($8744AUD) compared to standard testing followed by WGS ($24,894AUD). Financial analysis suggests that national adoption of diagnostic WGS testing would require a ninefold increase in government annual expenditure compared to conventional testing.

CONCLUSIONS

These findings make a case for replacing conventional testing with WGS to deliver clinically important benefits for cancer patients and families. The uptake of such an approach will depend on the perspectives of different payers on affordability.

Combined loss of CDH1 and downstream regulatory sequences drive early-onset diffuse gastric cancer and increase penetrance of hereditary diffuse gastric cancer

BACKGROUND

Germline CDH1 pathogenic or likely pathogenic variants cause hereditary diffuse gastric cancer (HDGC). Once a genetic cause is identified, stomachs' and breasts' surveillance and/or prophylactic surgery is offered to asymptomatic CDH1 carriers, which is life-saving. Herein, we characterized an inherited mechanism responsible for extremely early-onset gastric cancer and atypical HDGC high penetrance.

METHODS

Whole-exome sequencing (WES) re-analysis was performed in an unsolved HDGC family. Accessible chromatin and CDH1 promoter interactors were evaluated in normal stomach by ATAC-seq and 4C-seq, and functional analysis was performed using CRISPR-Cas9, RNA-seq and pathway analysis.

RESULTS

We identified a germline heterozygous 23 Kb CDH1-TANGO6 deletion in a family with eight diffuse gastric cancers, six before age 30. Atypical HDGC high penetrance and young cancer-onset argued towards a role for the deleted region downstream of CDH1, which we proved to present accessible chromatin, and CDH1 promoter interactors in normal stomach. CRISPR-Cas9 edited cells mimicking the CDH1-TANGO6 deletion display the strongest CDH1 mRNA downregulation, more impacted adhesion-associated, type-I interferon immune-associated and oncogenic signalling pathways, compared to wild-type or CDH1-deleted cells. This finding solved an 18-year family odyssey and engaged carrier family members in a cancer prevention pathway of care.

CONCLUSION

In this work, we demonstrated that regulatory elements lying down-stream of CDH1 are part of a chromatin network that control CDH1 expression and influence cell transcriptome and associated signalling pathways, likely explaining high disease penetrance and very young cancer-onset. This study highlights the importance of incorporating scientific-technological updates and clinical guidelines in routine diagnosis, given their impact in timely genetic diagnosis and disease prevention.

Genetic Testing in Parkinson's Disease

Genetic testing for persons with Parkinson's disease is becoming increasingly common. Significant gains have been made regarding genetic testing methods, and testing is becoming more readily available in clinical, research, and direct-to-consumer settings. Although the potential utility of clinical testing is expanding, there are currently no proven gene-targeted therapies, but clinical trials are underway. Furthermore, genetic testing practices vary widely, as do knowledge and attitudes of relevant stakeholders. The specter of testing mandates financial, ethical, and physician engagement, and there is a need for guidelines to help navigate the myriad of challenges. However, to develop guidelines, gaps and controversies need to be clearly identified and analyzed. To this end, we first reviewed recent literature and subsequently identified gaps and controversies, some of which were partially addressed in the literature, but many of which are not well delineated or researched. Key gaps and controversies include: (1) Is genetic testing appropriate in symptomatic and asymptomatic individuals without medical actionability? (2) How, if at all, should testing vary based on ethnicity? (3) What are the long-term outcomes of consumer- and research-based genetic testing in presymptomatic PD? (4) What resources are needed for clinical genetic testing, and how is this impacted by models of care and cost-benefit considerations? Addressing these issues will help facilitate the development of consensus and guidelines regarding the approach and access to genetic testing and counseling. This is also needed to guide a multidisciplinary approach that accounts for cultural, geographic, and socioeconomic factors in developing testing guidelines. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Evolution of virtual gene panels over time and implications for genomic data re-analysis

Purpose

Re-analyzing genomic information from patients without a molecular diagnosis is known to improve diagnostic yields. There are different mechanisms responsible for this increase, but the discovery of new, and refinement of existing, gene-disease relationships are one of the most prominent drivers of new diagnoses. This study examines the incorporation of new knowledge into virtual diagnostic gene panels and how this affects the potential for re-analysis.

Methods

We used PanelApp Australia to explore how the gene content of 112 rare-disease panels evolved between 2019 and 2022. By dividing these panels into groups that examined Specific and Broad rare-diseases clinical testing indications, we determined the granular changes in panel composition.

Results

Characterizing how the panels present at the launch of PanelApp Australia changed, revealed that the diagnostic genes available for analysis increased in 82% of the Specific rare-disease panels and in 97% of the Broad rare-disease panels. Examining how the panels had evolved showed that different panels were changing at different rates and in different ways. The median number of diagnostic grade genes in the Specific rare-disease panel increased by 4 (0-63), whereas the median number of gene gains in the Broad rare-disease panels was 27 (0-432). Monthly snapshots demonstrated that these changes were highly variable among different panels.

Conclusion

Knowledge about gene-disease associations is changing dynamically. Using fixed time periods may not be the best strategy to guide re-analysis frequency, as a result, some conditions may benefit from an approach based on the availability of new information rather than the passage of time.

EGAsubmitter: A software to automate submission of nucleic acid sequencing data to the European Genome-phenome Archive

Making raw data available to the research community is one of the pillars of Findability, Accessibility, Interoperability, and Reuse (FAIR) research. However, the submission of raw data to public databases still involves many manually operated procedures that are intrinsically time-consuming and error-prone, which raises potential reliability issues for both the data themselves and the ensuing metadata. For example, submitting sequencing data to the European Genome-phenome Archive (EGA) is estimated to take 1 month overall, and mainly relies on a web interface for metadata management that requires manual completion of forms and the upload of several comma separated values (CSV) files, which are not structured from a formal point of view. To tackle these limitations, here we present EGAsubmitter, a Snakemake-based pipeline that guides the user across all the submission steps, ranging from files encryption and upload, to metadata submission. EGASubmitter is expected to streamline the automated submission of sequencing data to EGA, minimizing user errors and ensuring higher end product fidelity.

Reevaluation of ambiguous genetic variants in sudden unexplained deaths of a young cohort

Sudden death cases in the young population remain without a conclusive cause of decease in almost 40% of cases. In these situations, cardiac arrhythmia of genetic origin is suspected as the most plausible cause of death. Molecular autopsy may reveal a genetic defect in up to 20% of families. Most than 80% of rare variants remain classified with an ambiguous role, impeding a useful clinical translation. Our aim was to update rare variants originally classified as of unknown significance to clarify their role. Our cohort included fifty-one post-mortem samples of young cases who died suddenly and without a definite cause of death. Five years ago, molecular autopsy identified at least one rare genetic alteration classified then as ambiguous following the American College of Medical Genetics and Genomics' recommendations. We have reclassified the same rare variants including novel data. About 10% of ambiguous variants change to benign/likely benign mainly because of improved population frequencies. Excluding cases who died before one year of age, almost 21% of rare ambiguous variants change to benign/likely benign. This fact makes it important to discard these rare variants as a cause of sudden unexplained death, avoiding anxiety in relatives' carriers. Twenty-five percent of the remaining variants show a tendency to suspicious deleterious role, highlighting clinical follow-up of carriers. Periodical reclassification of rare variants originally classified as ambiguous is crucial, at least updating frequencies every 5 years. This action aids to increase accuracy to enable and conclude a cause of death as well as translation into the clinic.

Bridging clinical care and research in Ontario, Canada: Maximizing diagnoses from reanalysis of clinical exome sequencing data

We examined the utility of clinical and research processes in the reanalysis of publicly-funded clinical exome sequencing data in Ontario, Canada. In partnership with eight sites, we recruited 287 families with suspected rare genetic diseases tested between 2014 and 2020. Data from seven laboratories was reanalyzed with the referring clinicians. Reanalysis of clinically relevant genes identified diagnoses in 4% (13/287); four were missed by clinical testing. Translational research methods, including analysis of novel candidate genes, identified candidates in 21% (61/287). Of these, 24 families have additional evidence through data sharing to support likely diagnoses (8% of cohort). This study indicates few diagnoses are missed by clinical laboratories, the incremental gain from reanalysis of clinically-relevant genes is modest, and the highest yield comes from validation of novel disease-gene associations. Future implementation of translational research methods, including continued reporting of compelling genes of uncertain significance by clinical laboratories, should be considered to maximize diagnoses.

An In-Depth Single-Gene Worldwide Carrier Frequency and Genetic Prevalence Analysis of CYP4V2 as the Cause of Bietti Crystalline Dystrophy

Conclusions

Our analysis estimates BCD prevalence and revealed large differences among various populations. Moreover, it highlights advantages and limitations of the gnomAD database.

Methods

CYP4V2 gnomAD data and reported mutations were used to calculate carrier frequency of each variant. An evolutionary-based sliding window analysis was used to detect conserved protein regions. Potential exonic splicing enhancers (ESEs) were identified using ESEfinder.

Purpose

Bietti crystalline dystrophy (BCD) is a rare monogenic autosomal recessive (AR) chorioretinal degenerative disease caused by biallelic mutations in CYP4V2. The aim of the current study was to perform an in-depth calculation of worldwide carrier frequency and genetic prevalence of BCD using gnomAD data and comprehensive literature CYP4V2 analysis.

Results

We identified 1171 CYP4V2 variants, 156 of which were considered pathogenic, including 108 reported in patients with BCD. Carrier frequency and genetic prevalence calculations confirmed that BCD is more common in the East Asian population, with ∼19 million healthy carriers and 52,000 individuals who carry biallelic CYP4V2 mutations and are expected to be affected. Additionally, we generated BCD prevalence estimates of other populations, including African, European, Finnish, Latino, and South Asian. Worldwide, the estimated overall carrier frequency of CYP4V2 mutation is 1:210, and therefore, ∼37 million individuals are expected to be healthy carriers of a CYP4V2 mutation. The estimated genetic prevalence of BCD is about 1:116,000, and we predict that ∼67,000 individuals are affected with BCD worldwide.

Translational Relevance

This analysis is likely to have important implications for genetic counseling in each studied population and for developing clinical trials for potential BCD treatments.

The role of genetic testing in the diagnostic workflow of pediatric patients with kidney diseases: the experience of a single institution

PURPOSE

Inherited kidney diseases are among the leading causes of kidney failure in children, resulting in increased mortality, high healthcare costs and need for organ transplantation. Next-generation sequencing technologies can help in the diagnosis of rare monogenic conditions, allowing for optimized medical management and therapeutic choices.

METHODS

Clinical exome sequencing (CES) was performed on a cohort of 191 pediatric patients from a single institution, followed by Sanger sequencing to confirm identified variants and for family segregation studies.

RESULTS

All patients had a clinical diagnosis of kidney disease: the main disease categories were glomerular diseases (32.5%), ciliopathies (20.4%), CAKUT (17.8%), nephrolithiasis (11.5%) and tubular disease (10.5%). 7.3% of patients presented with other conditions. A conclusive genetic test, based on CES and Sanger validation, was obtained in 37.1% of patients. The highest detection rate was obtained for ciliopathies (74.4%), followed by nephrolithiasis (45.5%), tubular diseases (45%), while most glomerular diseases and CAKUT remained undiagnosed.

CONCLUSIONS

Results indicate that genetic testing consistently used in the diagnostic workflow of children with chronic kidney disease can (i) confirm clinical diagnosis, (ii) provide early diagnosis in the case of inherited conditions, (iii) find the genetic cause of previously unrecognized diseases and (iv) tailor transplantation programs.

The practice of genomic medicine: A delineation of the process and its governing principles

Genomic medicine, an emerging medical discipline, applies the principles of evolution, developmental biology, functional genomics, and structural genomics within clinical care. Enabling widespread adoption and integration of genomic medicine into clinical practice is key to achieving precision medicine. We delineate a biological framework defining diagnostic utility of genomic testing and map the process of genomic medicine to inform integration into clinical practice. This process leverages collaboration and collective cognition of patients, principal care providers, clinical genomic specialists, laboratory geneticists, and payers. We detail considerations for referral, triage, patient intake, phenotyping, testing eligibility, variant analysis and interpretation, counseling, and management within the utilitarian limitations of health care systems. To reduce barriers for clinician engagement in genomic medicine, we provide several decision-making frameworks and tools and describe the implementation of the proposed workflow in a prototyped electronic platform that facilitates genomic care. Finally, we discuss a vision for the future of genomic medicine and comment on areas for continued efforts.

Emerging bone marrow failure syndromes- new pieces to an unsolved puzzle

Inherited bone marrow failure (BMF) syndromes are genetically diverse - more than 100 genes have been associated with those syndromes and the list is rapidly expanding. Risk assessment and genetic counseling of patients with recently discovered BMF syndromes is inherently difficult as disease mechanisms, penetrance, genotype-phenotype associations, phenotypic heterogeneity, risk of hematologic malignancies and clonal markers of disease progression are unknown or unclear. This review aims to shed light on recently described BMF syndromes with sparse concise data and with an emphasis on those associated with germline variants in ADH5/ALDH2, DNAJC21, ERCC6L2 and MECOM. This will provide important data that may help to individualize and improve care for these patients.

Intronic variants in inborn errors of metabolism: Beyond the exome

Non-coding regions are areas of the genome that do not directly encode protein and were initially thought to be of little biological relevance. However, subsequent identification of pathogenic variants in these regions indicates there are exceptions to this assertion. With the increasing availability of next generation sequencing, variants in non-coding regions are often considered when no causative exonic changes have been identified. There is still a lack of understanding of normal human variation in non-coding areas. As a result, potentially pathogenic non-coding variants are initially classified as variants of uncertain significance or are even overlooked during genomic analysis. In most cases where the phenotype is non-specific, clinical suspicion is not sufficient to warrant further exploration of these changes, partly due to the magnitude of non-coding variants identified. In contrast, inborn errors of metabolism (IEMs) are one group of genetic disorders where there is often high phenotypic specificity. The clinical and biochemical features seen often result in a narrow list of diagnostic possibilities. In this context, there have been numerous cases in which suspicion of a particular IEM led to the discovery of a variant in a non-coding region. We present four patients with IEMs where the molecular aetiology was identified within non-coding regions. Confirmation of the molecular diagnosis is often aided by the clinical and biochemical specificity associated with IEMs. Whilst the clinical severity associated with a non-coding variant can be difficult to predict, obtaining a molecular diagnosis is crucial as it ends diagnostic odysseys and assists in management.

Early cost-utility analysis of genetically guided therapy for patients with drug-resistant epilepsy

OBJECTIVE

Existing gene panels were developed to understand the etiology of epilepsy, and further benefits will arise from an effective pharmacogenomics panel for personalizing therapy and achieving seizure control. Our study assessed the cost-effectiveness of a pharmacogenomics panel for patients with drug-resistant epilepsy, compared with usual care.

METHODS

A cost-utility analysis was employed using a discrete event simulation model. The microsimulation model aggregated the costs and benefits of genetically guided treatment versus usual care for 5000 simulated patients. The 10-year model combined data from various sources including genomic databases on prevalence of variants, population-level pharmaceutical claims on antiseizure medications, published long-term therapy retention rates, patient-level cost data, and systematic reviews. Incremental cost per quality-adjusted life-year (QALY) gained was computed. Deterministic and probabilistic sensitivity analyses were undertaken to address uncertainty in model parameters.

RESULTS

The mean cost of the genetically guided treatment option was AU$98 199 compared with AU$95 386 for usual care. Corresponding mean QALYs were 4.67 compared with 4.28 for genetically guided and usual care strategies, respectively. The incremental cost per QALY gained was AU$7381. In probabilistic sensitivity analyses, the incremental cost per QALY gained was AU$6321 (95% uncertainty interval = AU$3604-AU$9621), with a 100% likelihood of being cost-effective in the Australian health care system. The most influential drivers of the findings were the monthly health care costs associated with reduced seizures, costs when seizures continued, and the quality-of-life estimates under genetically guided and usual care strategies.

SIGNIFICANCE

This early economic evaluation of a pharmacogenomics panel to guide treatment for drug-resistant epilepsy could potentially be cost-effective in the Australian health care system. Clinical trial evidence is necessary to confirm these findings.

Challenges of variant reinterpretation: Opinions of stakeholders and need for guidelines

PURPOSE

The knowledge used to classify genetic variants is continually evolving, and the classification can change on the basis of newly available data. Although up-to-date variant classification is essential for clinical management, reproductive planning, and identifying at-risk family members, there is no consistent practice across laboratories or clinicians on how or under what circumstances to perform variant reinterpretation.

METHODS

We conducted exploratory focus groups (N = 142) and surveys (N = 1753) with stakeholders involved in the process of variant reinterpretation (laboratory directors, clinical geneticists, genetic counselors, nongenetic providers, and patients/parents) to assess opinions on key issues, including initiation of reinterpretation, variants to report, termination of the responsibility to reinterpret, and concerns about consent, cost, and liability.

RESULTS

Stakeholders widely agreed that there should be no fixed termination point to the responsibility to reinterpret a previously reported genetic variant. There were significant concerns about liability and lack of agreement about many logistical aspects of variant reinterpretation.

CONCLUSION

Our findings suggest a need to (1) develop consensus and (2) create transparency and awareness about the roles and responsibilities of parties involved in variant reinterpretation. These data provide a foundation for developing guidelines on variant reinterpretation that can aid in the development of a low-cost, scalable, and accessible approach.

Genetic overlap between dystonia and other neurologic disorders: A study of 1,100 exomes

INTRODUCTION

Although shared genetic factors have been previously reported between dystonia and other neurologic conditions, no sequencing study exploring such links is available. In a large dystonic cohort, we aimed at analyzing the proportions of causative variants in genes associated with disease categories other than dystonia.

METHODS

Gene findings related to whole-exome sequencing-derived diagnoses in 1100 dystonia index cases were compared with expert-curated molecular testing panels for ataxia, parkinsonism, spastic paraplegia, neuropathy, epilepsy, and intellectual disability.

RESULTS

Among 220 diagnosed patients, 21% had variants in ataxia-linked genes; 15% in parkinsonism-linked genes; 15% in spastic-paraplegia-linked genes; 12% in neuropathy-linked genes; 32% in epilepsy-linked genes; and 65% in intellectual-disability-linked genes. Most diagnosed presentations (80%) were related to genes listed in ≥1 studied panel; 71% of the involved loci were found in the non-dystonia panels but not in an expert-curated gene list for dystonia.

CONCLUSIONS

Our study indicates a convergence in the genetics of dystonia and other neurologic phenotypes, informing diagnostic evaluation strategies and pathophysiological considerations.

Newborn screening for neurodevelopmental diseases: Are we there yet?

In the US, newborn screening (NBS) is a unique health program that supports health equity and screens virtually every baby after birth, and has brought timely treatments to babies since the 1960's. With the decreasing cost of sequencing and the improving methods to interpret genetic data, there is an opportunity to add DNA sequencing as a screening method to facilitate the identification of babies with treatable conditions that cannot be identified in any other scalable way, including highly penetrant genetic neurodevelopmental disorders (NDD). However, the lack of effective dietary or drug-based treatments has made it nearly impossible to consider NDDs in the current NBS framework, yet it is anticipated that any treatment will be maximally effective if started early. Hence there is a critical need for large scale pilot studies to assess if and how NDDs can be effectively screened at birth, if parents desire that information, and what impact early diagnosis may have. Here we attempt to provide an overview of the recent advances in NDD treatments, explore the possible framework of setting up a pilot study to genetically screen for NDDs, highlight key technical, practical, and ethical considerations and challenges, and examine the policy and health system implications.