The value of genomic variant ClinVar submissions from clinical providers: Beyond the addition of novel variants

Slice Testing-Considerations from Ordering to Reporting: A Joint Report of the Association for Molecular Pathology, College of American Pathologists, and National Society of Genetic Counselors

As the number of genes associated with various germline disorders continues to grow, it is becoming more difficult for clinical laboratories to maintain separate assays for interrogating disease-focused gene panels. One solution to this challenge is termed slice testing, where capture backbone is used to analyze data specific to a set of genes, and for this article, we will focus on exome. A key advantage to this strategy is greater flexibility by adding genes as they become associated with disease or the ability to accommodate specific provider requests. Here, we provide expert consensus recommendations and results from an Association for Molecular Pathology-sponsored survey of clinical laboratories performing exome sequencing to compare a slice testing approach with traditional static gene panels and comprehensive exome analysis. We explore specific considerations for slices, including gene selection, analytic performance, coverage, quality, and interpretation. Our goal is to provide comprehensive guidance for clinical laboratories interested in designing and using slice tests as a diagnostic.

Gene Therapy for Genetic Syndromes: Understanding the Current State to Guide Future Care

Gene therapy holds promise as a life-changing option for individuals with genetic variants that give rise to disease. FDA-approved gene therapies for Spinal Muscular Atrophy (SMA), cerebral adrenoleukodystrophy, β-Thalassemia, hemophilia A/B, retinal dystrophy, and Duchenne Muscular Dystrophy have generated buzz around the ability to change the course of genetic syndromes. However, this excitement risks over-expansion into areas of genetic disease that may not fit the current state of gene therapy. While in situ (targeted to an area) and ex vivo (removal of cells, delivery, and administration of cells) approaches show promise, they have a limited target ability. Broader in vivo gene therapy trials have shown various continued challenges, including immune response, use of immune suppressants correlating to secondary infections, unknown outcomes of overexpression, and challenges in driving tissue-specific corrections. Viral delivery systems can be associated with adverse outcomes such as hepatotoxicity and lethality if uncontrolled. In some cases, these risks are far outweighed by the potentially lethal syndromes for which these systems are being developed. Therefore, it is critical to evaluate the field of genetic diseases to perform cost-benefit analyses for gene therapy. In this work, we present the current state while setting forth tools and resources to guide informed directions to avoid foreseeable issues in gene therapy that could prevent the field from continued success.

Genetic variants with discordant classifications: An assessment of genetic counselor attitudes and practices

Discordant variant classifications (DVCs) can impact patient care and pose challenges for clinicians. A survey-based study was conducted to examine genetic counselor (GC) attitudes and practices related to DVCs. Most GCs (202/229, 88%) in the study provide direct patient care across clinical specialties; review patients' genetic test results to determine if reported genetic variants have DVCs (176/202, 88%); and inform patients of known DVCs that impact medical management (165/202, 82%). DVC review, which takes 41 min (range: 5-240) on average per week, is typically prompted by the identification of a variant of uncertain significance (VUS) (160/176, 90%) and is primarily conducted using public databases (176/176, 100%). While most GCs felt it would not be ethical to knowingly provide different medical management recommendations to patients with the same genetic variant (152/229, 66%), they also stated they would rely on the variant classification on the test report (141/229, 61%) and/or the patient's personal/family history (188/229, 82%) to determine which classification to follow if a DVC is identified. Both factors are patient-specific and, inherently, could lead to differing recommendations. When posed with a hypothetical scenario in which two patients have the same genetic variant, but test reports show a DVC (pathogenic vs VUS), most GCs (179/229, 78.2%) stated they would make the same recommendation for both patients regardless of management guidelines. One-third (52/179, 29.1%) cited patient-specific factors, such as personal/family history, would impact their recommendations. Disagreements about whether the pathogenic or VUS classification should be used to make medical management recommendations were noted. Differing practices and opinions on how to manage patients with DVCs, as well as the fact that most GCs (209/229, 91.3%) have consulted with colleagues on this matter, highlight the need for more professional guidance to ensure equitable patient care.

Exome/Genome-Wide Testing in Newborn Screening: A Proportionate Path Forward

Population-based newborn screening (NBS) is among the most effective public health programs ever launched, improving health outcomes for newborns who screen positive worldwide through early detection and clinical intervention for genetic disorders discovered in the earliest hours of life. Key to the success of newborn screening programs has been near universal accessibility and participation. Interest has been building to expand newborn screening programs to also include many rare genetic diseases that can now be identified by exome or genome sequencing (ES/GS). Significant declines in sequencing costs as well as improvements to sequencing technologies have enabled researchers to elucidate novel gene-disease associations that motivate possible expansion of newborn screening programs. In this paper we consider recommendations from professional genetic societies in Europe and North America in light of scientific advances in ES/GS and our current understanding of the limitations of ES/GS approaches in the NBS context. We invoke the principle of proportionality-that benefits clearly outweigh associated risks-and the human right to benefit from science to argue that rigorous evidence is still needed for ES/GS that demonstrates clinical utility, accurate genomic variant interpretation, cost effectiveness and universal accessibility of testing and necessary follow-up care and treatment. Confirmatory or second-tier testing using ES/GS may be appropriate as an adjunct to conventional newborn screening in some circumstances. Such cases could serve as important testbeds from which to gather data on relevant programmatic barriers and facilitators to wider ES/GS implementation.

Using Long-Term Follow-Up Data to Classify Genetic Variants in Newborn Screened Conditions

With the rapid increase in publicly available sequencing data, healthcare professionals are tasked with understanding how genetic variation informs diagnosis and affects patient health outcomes. Understanding the impact of a genetic variant in disease could be used to predict susceptibility/protection and to help build a personalized medicine profile. In the United States, over 3.8 million newborns are screened for several rare genetic diseases each year, and the follow-up testing of screen-positive newborns often involves sequencing and the identification of variants. This presents the opportunity to use longitudinal health information from these newborns to inform the impact of variants identified in the course of diagnosis. To test this, we performed secondary analysis of a 10-year natural history study of individuals diagnosed with metabolic disorders included in newborn screening (NBS). We found 564 genetic variants with accompanying phenotypic data and identified that 161 of the 564 variants (29%) were not included in ClinVar. We were able to classify 139 of the 161 variants (86%) as pathogenic or likely pathogenic. This work demonstrates that secondary analysis of longitudinal data collected as part of NBS finds unreported genetic variants and the accompanying clinical information can inform the relationship between genotype and phenotype.

GA4GH: International policies and standards for data sharing across genomic research and healthcare

The Global Alliance for Genomics and Health (GA4GH) aims to accelerate biomedical advances by enabling the responsible sharing of clinical and genomic data through both harmonized data aggregation and federated approaches. The decreasing cost of genomic sequencing (along with other genome-wide molecular assays) and increasing evidence of its clinical utility will soon drive the generation of sequence data from tens of millions of humans, with increasing levels of diversity. In this perspective, we present the GA4GH strategies for addressing the major challenges of this data revolution. We describe the GA4GH organization, which is fueled by the development efforts of eight Work Streams and informed by the needs of 24 Driver Projects and other key stakeholders. We present the GA4GH suite of secure, interoperable technical standards and policy frameworks and review the current status of standards, their relevance to key domains of research and clinical care, and future plans of GA4GH. Broad international participation in building, adopting, and deploying GA4GH standards and frameworks will catalyze an unprecedented effort in data sharing that will be critical to advancing genomic medicine and ensuring that all populations can access its benefits.

Genetic variant interpretation: a primer for clinicians

Clinicians beyond specialist genetic services are now able to order tests to interrogate the genetic basis of disease. Behind every genetic report lies a significant body of work that draws on decades of collaboration between clinicians, researchers and database curators. Understanding these advances in genetic variant interpretation may allow practising clinicians to develop a more nuanced appreciation of the role genetic variant interpretation can play in the diagnosis and management of heritable disorders. In this article, we consider genetic variant interpretation with reference to efforts to better understand variation in the mismatch repair genes and their relation to Lynch syndrome - the most common cause of hereditary colon cancer.

Clinical Exome Reanalysis: Current Practice and Beyond

Novel gene-disease discoveries, rapid advancements in technology, and improved bioinformatics tools all have the potential to yield additional molecular diagnoses through the reanalysis of exome sequencing data. Collaborations between clinical laboratories, ordering physicians, and researchers are also driving factors that can contribute to these new insights. Automation in ongoing natural history collection, evolving phenotype updates, advancements in processing next-generation sequencing data, and up-to-date variant-gene-disease databases are increasingly needed for systematic exome reanalysis. Here, we review some of the advantages and challenges for clinician-initiated and laboratory-initiated exome reanalysis, and we propose a model for the future that could potentially maximize the clinical utility of exome reanalysis by integrating information from electronic medical records and knowledge databases into routine clinical workflows.

Challenges in genetic testing: clinician variant interpretation processes and the impact on clinical care

PURPOSE

Efforts have been made to standardize laboratory variant interpretation, but clinicians are ultimately tasked with clinical correlation and application of genetic test results in patient care. This study aimed to explore processes clinicians utilize when reviewing and returning genetic test results, and how they impact patient care.

METHODS

Medical geneticists, genetic counselors, and nongenetics clinicians from two Midwestern states completed surveys (n = 98) and in-depth interviews (n = 29) on practices of reviewing and returning genetic test results. Retrospective chart review (n = 130) examined discordant interpretations and the impact on care.

RESULTS

Participants reported variable behaviors in both reviewing and returning results based on factors such as confidence, view of role, practice setting, and relationship with the lab. Providers did not report requesting changes to variant classifications from laboratories, but indicated relaying conflicting classifications to patients in some cases. Chart reviews revealed medically impactful differences in interpretation between laboratories and clinicians in 18 (13.8%) records.

CONCLUSION

Clinician practices for reviewing and integrating genetic test results into patient care vary within and between specialties and impact patient care. Strategies to better incorporate both laboratory and clinician expertise into interpretation of genetic results could result in improved care across providers and settings.

Harmonizing the Collection of Clinical Data on Genetic Testing Requisition Forms to Enhance Variant Interpretation in Hypertrophic Cardiomyopathy (HCM): A Study from the ClinGen Cardiomyopathy Variant Curation Expert Panel

Diagnostic laboratories gather phenotypic data through requisition forms, but there is no consensus as to which data are essential for variant interpretation. The ClinGen Cardiomyopathy Variant Curation Expert Panel defined a phenotypic data set for hypertrophic cardiomyopathy (HCM) variant interpretation, with the goal of standardizing requisition forms. Phenotypic data elements listed on requisition forms from nine leading cardiomyopathy testing laboratories were compiled to assess divergence in data collection. A pilot of 50 HCM cases was implemented to determine the feasibility of harmonizing data collection. Laboratory directors were surveyed to gauge potential for adoption of a minimal data set. Wide divergence was observed in the phenotypic data fields in requisition forms. The 50-case pilot showed that although demographics and assertion of a clinical diagnosis of HCM had 86% to 98% completion, specific phenotypic features, such as degree of left ventricular hypertrophy, ejection fraction, and suspected syndromic disease, were completed only 24% to 44% of the time. Nine data elements were deemed essential for variant classification by the expert panel. Participating laboratories unanimously expressed a willingness to adopt these data elements in their requisition forms. This study demonstrates the value of comparing and sharing best practices through an expert group, such as the ClinGen Program, to enhance variant interpretation, providing a foundation for leveraging cumulative case-level data in public databases and ultimately improving patient care.

A pediatric perspective on genomics and prevention in the twenty-first century

We present evidence from diverse disciplines and populations to identify the current and emerging role of genomics in prevention from both medical and public health perspectives as well as key challenges and potential untoward consequences of increasing the role of genomics in these endeavors. We begin by comparing screening in healthy populations (newborn screening), with testing in symptomatic populations, which may incidentally identify secondary findings and at-risk relatives. Emerging evidence suggests that variants in genes subject to the reporting of secondary findings are more common than expected in patients who otherwise would not meet the criteria for testing and population testing for variants in these genes may more precisely identify discrete populations to target for various prevention strategies starting in childhood. Conversely, despite its theoretical promise, recent studies attempting to demonstrate benefits of next-generation sequencing for newborn screening have instead demonstrated numerous barriers and pitfalls to this approach. We also examine the special cases of pharmacogenomics and polygenic risk scores as examples of ways genomics can contribute to prevention amongst a broader population than that affected by rare Mendelian disease. We conclude with unresolved questions which will benefit from future investigations of the role of genomics in disease prevention.

Variant interpretation is a component of clinical practice among genetic counselors in multiple specialties

PURPOSE

Genomic testing is routinely utilized across clinical settings and can have significant variant interpretation challenges. The extent of genetic counselor (GC) engagement in variant interpretation in clinical practice is unknown. This study aimed to explore clinical GCs' variant interpretation practice across specialties, understand outcomes of this practice, and identify resource and educational needs.

METHODS

An online survey was administered to National Society of Genetic Counselors members providing clinical counseling.

RESULTS

Respondents (n = 239) represented all major clinical specialties. The majority (68%) reported reviewing evidence documented by the laboratory for most (>60%) variants reported; 45.5% report seeking additional evidence. Prenatal GCs were less likely to independently assess reported evidence. Most respondents (67%) report having reached a different conclusion about a variant's classification than the testing laboratory, though infrequently. Time was the most commonly reported barrier (72%) to performing variant interpretation, though the majority (97%) indicated that this practice had an important impact on patient care. When presented with three hypothetical scenarios, evidence typically used for variant interpretation was generally applied correctly.

CONCLUSION

This study is the first to document variant interpretation practice broadly across clinical GC specialties. Our results suggest that variant interpretation should be considered a practice-based competency for GCs.