Sequence Variants of Uncertain Significance

Influence of Genetic Information on Neonatologists' Decisions: A Psychological Experiment

BACKGROUND AND OBJECTIVES

Genetic testing is expanding among ill neonates, yet the influence of genetic results on medical decision-making is not clear. With this study, we sought to determine how different types of genetic information with uncertain implications for prognosis influence clinicians' decisions to recommend intensive versus palliative care.

METHODS

We conducted a national study of neonatologists using a split sample experimental design. The questionnaire contained 4 clinical vignettes. Participants were randomly assigned to see one of 2 versions that varied only regarding whether they included the following genetic findings: (1) a variant of uncertain significance; (2) a genetic diagnosis that affects neurodevelopment but not acute survival; (3) a genetic versus nongenetic etiology of equally severe pathology; (4) a pending genetic testing result. Physicians answered questions about recommendations they would make for the patient described in each vignette.

RESULTS

Vignette versions that included a variant of uncertain significance, a diagnosis foreshadowing neurodevelopmental impairment, or a genetic etiology of disease were all associated with an increased likelihood of recommending palliative rather than intensive care. A pending genetic test result did not have a significant effect on care recommendations.

CONCLUSIONS

Findings from this study of hypothetical cases suggest neonatologists apply uncertain genetic findings or those that herald neurodevelopmental disability in problematic ways. As genetic testing expands, understanding how it is used in decision-making and educating clinicians regarding appropriate use are paramount.

Current Testing Guidelines: A Retrospective Analysis of a Community-Based Hereditary Cancer Program

It is estimated that 5% to 10% of all cancers are related to a hereditary cancer syndrome. However, specific cancers, such as pancreatic and ovarian cancers, are related to hereditary cancer syndromes 15% to 20% of the time. Genetic testing guidelines for hereditary cancer syndromes are frequently reviewed and updated by the National Comprehensive Cancer Network (NCCN). The purpose of this retrospective analysis is to identify carriers of pathogenic variants or hereditary cancer syndrome who do not meet NCCN criteria for testing and compare the results with previous studies. The data obtained can be used to provide recommendations to assess current guidelines for testing and evaluate the benefit of comprehensive panel testing vs. standard testing for specific hereditary cancer syndromes. This project is a retrospective review of clinical histories of patients who had multigene panel testing between September 2015 and February 2019 through a cancer outreach and risk assessment (CORA) program. Frequencies analyses were performed to analyze results. A total of 233 individuals were included in the analysis: 171 met BRCA1/2 testing criteria, 66 met Lynch syndrome criteria, and 4 met polyposis criteria. Of the individuals meeting established criteria for testing, 39 were identified with pathogenic variants. However, only 10 of these individuals were identified with a pathogenic variant associated with the criteria for which they met. Genetic testing that is limited to only those patients with genes associated with hereditary cancer syndromes may lead to exclusion of other potentially actionable genes, which may impair a patient's ability to receive additional screening or preventative measures.

Identification of LRRK2 missense variants in the accelerating medicines partnership Parkinson's disease cohort

Pathogenic missense variants in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified through linkage analysis in familial Parkinson disease (PD). Subsequently, other missense variants with lower effect sizes on PD risk have emerged, as well as non-coding polymorphisms (e.g. rs76904798) enriched in PD cases in genome-wide association studies. Here we leverage recent whole-genome sequences from the Accelerating Medicines Partnership-Parkinson's Disease (AMP-PD) and the Genome Aggregation (gnomAD) databases to characterize novel missense variants in LRRK2 and explore their relationships with known pathogenic and PD-linked missense variants. Using a computational prediction tool that successfully classifies known pathogenic LRRK2 missense variants, we describe an online web-based resource that catalogs characteristics of over 1200 LRRK2 missense variants of unknown significance. Novel high-pathogenicity scoring variants, some identified exclusively in PD cases, tightly cluster within the ROC-COR-Kinase domains. Structure-function predictions support that some of these variants exert gain-of-function effects with respect to LRRK2 kinase activity. In AMP-PD participants, all p.R1441G carriers (N = 89) are also carriers of the more common PD-linked variant p.M1646T. In addition, nearly all carriers of the PD-linked p.N2081D missense variant are also carriers of the LRRK2 PD-risk variant rs76904798. These results provide a compendium of LRRK2 missense variants and how they associate with one another. While the pathogenic p.G2019S variant is by far the most frequent high-pathogenicity scoring variant, our results suggest that ultra-rare missense variants may have an important cumulative impact in increasing the number of individuals with LRRK2-linked PD.

Physician interpretation of variants of uncertain significance

A growing number of physicians will interact with genetic test results as testing becomes more commonplace. While variants of uncertain significance can complicate results, it is equally important that physicians understand how to incorporate these results into clinical care. An online survey was created to assess physician self-reported comfort level with genetics and variants of uncertain significance. Physicians were asked to respond to three case examples involving genetic test results. The survey was sent to 488 physicians at Mayo Clinic FL on 8/16/2017. Physicians from all specialties were invited to participate. A total of 92 physicians responded to the survey. Only 13/84 (14.6%) responded to all three case examples with the answer deemed "most correct" by review of literature. Physicians that specialized in cancer were more likely to answer questions appropriately (P = .02). Around half (39/84) of the physicians incorrectly defined a variant of uncertain significance (VUS). Over 75% made a recommendation for genetic testing that was not warranted. Many physicians have never received formal genetics training; however, they will be expected to provide an accurate explanation of the genetic test results and subsequent evidence-based medical management recommendations. These results demonstrate that a substantial proportion of physicians lack a true understanding of the implications a VUS. Utilization of supplemental genetics training programs coupled with increase awareness of genetic services may help to improve patient care.

Factors predicting reclassification of variants of unknown significance

Genetic variants of unknown significance (VUS) are an increasingly common result of genetic testing. VUS present dilemmas for treatment and surveillance. Family history may play a role in VUS reclassification over time.

METHODS

All genetic tests performed at a tertiary referral center 2006-2015 were evaluated for the presence of VUS. Patients with VUS were evaluated for demographics, clinical characteristics, family history, and gene characteristics.

RESULTS

In total, 2291 individuals were tested from 1639 families; 150 VUS were identified. Twenty-eight VUS reclassified, 21 to benign and 7 to pathogenic. Logistic regression demonstrated the number of family members with associated phenotypic disease was a significant predictor of reclassification.

CONCLUSION

The likelihood of VUS reclassification can be predicted by increased positive family history of disease. Most VUS reclassify to benign, but one-fourth reclassify to pathogenic. The actual risk of a VUS should be assessed based on family history and routinely checked for reclassification.

Effects of Cancer Genetic Panel Testing on at-Risk Individuals

OBJECTIVE

To evaluate the role of screening patients at increased risk for hereditary cancer syndromes with an extended panel of cancer predisposition genes to identify actionable genetic mutations.

METHODS

A retrospective chart review was conducted of all patients presenting to a multidisciplinary cancer program for genetic counseling and testing from January 2015 to December 2016. Individuals presenting to the program were identified as at-risk by a personal or family history of cancer, by their health care provider, or by self-referral. All participants met current National Comprehensive Cancer Network criteria for genetic risk evaluation for hereditary cancer. The results of testing and its implications for management, based on National Comprehensive Cancer Network guidelines, were recorded.

RESULTS

Of 670 at-risk patients who underwent genetic testing, 66 (9.9%) had BRCA-limited testing; of these, 26 of 670 (3.9%) had a deleterious or likely pathogenic mutation. Expanded panel testing was done for 560 of the 670 patients (83.4%), and abnormal results were found in 65 of 670 (9.7%); non-BRCA mutations (predominantly CHEK2) were found in 49 of the 65 (75%). Abnormal genetic testing was associated with increased surveillance in 96% of those with deleterious mutations, whereas negative testing for a known familial mutation in 45 patients was associated with a downgrade of their risk and reduction of subsequent surveillance and management.

CONCLUSION

Guideline-based management is frequently altered by genetic testing, including panel testing, in patients at risk for cancer. We recommend that obstetrics and gynecology providers routinely refer at-risk patients for genetic counseling and testing when clinically appropriate.

Multi-gene panel testing for hereditary cancer susceptibility in a rural Familial Cancer Program

This study explores our Familial Cancer Program's experience implementing multi-gene panel testing in a largely rural patient population. We conducted a retrospective review of patients undergoing panel testing between May 2011 and August 2015. Our goal was to evaluate factors that might be predictors of identifying variants (pathogenic or uncertain significance) and to assess clinical management changes due to testing. We utilized a structured family history tool to determine the significance of patient's family histories with respect to identification of genetic variants. A total of 227 patients underwent panel testing at our center and 67 patients (29.5 %) had variants identified, with 8 (3.5 %) having multiple variants. Overall, 44 patients (19.4 %) had a variant of uncertain significance (VUS) and 28 patients (12.3 %) had a pathogenic variant detected, with 10 (4.4 %) having pathogenic variants in highly penetrant genes. We found no statistical difference in patient familial and personal cancer history, age, rural status, Ashkenazi Jewish ancestry, insurance coverage and prior single-gene testing among those with pathogenic, VUS and negative panel testing results. There were no predictors of pathogenic variants on regression analysis. Panel testing changed cancer screening and management guidelines from that expected based on family history alone in 13.2 % of patients. Ultimately, cancer panel testing does yield critical information not identified by traditional single gene testing but maximal utility through a broad range of personal and family histories requires improved interpretation of variants.

Applying targeted next generation sequencing to dried blood spot specimens from suspicious cases identified by tandem mass spectrometry-based newborn screening

BACKGROUND

Tandem mass spectrometry (TMS)-based newborn screening has been proven successful as one of the public healthcare programs, although the practicability has not yet been specifically addressed.

METHODS

Sixty residual dried blood spot (DBS) specimens from confirmation/diagnosis-insufficient cases discovered by TMS screening were analyzed by targeted next generation sequencing (TNGS) assay.

RESULTS

In total, 26, 11, 9, and 14 cases were diagnosed as positive, high risk, low risk, and negative, respectively.

CONCLUSIONS

Applying the DBS-based TNGS assay for the accurate and rapid diagnosis of inborn errors of metabolism (IEMs) is feasible, competent, and advantageous, enabling a simplified TMS screening-based, TNGS assay-integrated newborn screening scheme highlighting an efficient, executable, and one-step screening-to-diagnosis workflow.

The role of screening MRI in the era of next generation sequencing and moderate-risk genetic mutations

With the advent of next-generation sequencing, the ability to rapidly analyze numerous genes simultaneously has led to the creation of large cancer gene panels. Some of these genes, like BRCA1 and BRCA2, have been heavily researched and have well-established management guidelines. Other more newly established genes, like ATM, CHEK2, and PALB2, have previously had less robust research surrounding them which has limited the ability to create accurate risk estimates. With their inclusion on gene panels, there has been more pressure to produce management guidelines for patients discovered to carry pathogenic variants in these genes. For known high-risk genes, it is recommended for breast magnetic resonance imaging (MRI) and mammogram to be offered annually. This combination has been proven to be more effective at detecting breast cancer than mammography alone, with a combined sensitivity of 94% (Leach et al. in Lancet 365(9473):1769-1778, 2005). Women with a lifetime risk of breast cancer of 20% and higher have been recommended to have both breast MRI and mammography performed (Saslow et al. in CA Cancer J Clin 57(2):75-89, 2007). For women with pathogenic variants detected in moderate risk genes with lifetime breast cancer risks of at least 20%, breast MRI should be offered as part of their management. For more newly discovered genes with suspected associated risks at or above 20%, the use of breast MRI should be considered for their management as well.

Consensus Statement on next-generation-sequencing-based diagnostic testing of hereditary phaeochromocytomas and paragangliomas

Phaeochromocytomas and paragangliomas (PPGLs) are neural-crest-derived tumours of the sympathetic or parasympathetic nervous system that are often inherited and are genetically heterogeneous. Genetic testing is recommended for patients with these tumours and for family members of patients with hereditary forms of PPGLs. Due to the large number of susceptibility genes implicated in the diagnosis of inherited PPGLs, next-generation sequencing (NGS) technology is ideally suited for carrying out genetic screening of these individuals. This Consensus Statement, formulated by a study group comprised of experts in the field, proposes specific recommendations for the use of diagnostic NGS in hereditary PPGLs. In brief, the study group recommends target gene panels for screening of germ line DNA, technical adaptations to address different modes of disease transmission, orthogonal validation of NGS findings, standardized classification of variant pathogenicity and uniform reporting of the findings. The use of supplementary assays, to aid in the interpretation of the results, and sequencing of tumour DNA, for identification of somatic mutations, is encouraged. In addition, the study group launches an initiative to develop a gene-centric curated database of PPGL variants, with annual re-evaluation of variants of unknown significance by an expert group for purposes of reclassification and clinical guidance.

Assessing, Counseling, and Treating Patients at High Risk for Breast Cancer

Identifying patients at high risk of carrying pathogenic variants in genes is a crucial part of providing both accurate counseling and evidence-based treatment recommendations. Current risk assessment models have strengths and weaknesses that may limit their applicability to specific clinical circumstances. Clinicians must have knowledge regarding variations in available models, how they should be used, and what data they can expect from specific models. In addition, indications for genetic testing are expanding, and the adoption of next-generation sequencing has allowed the creation of multigene testing panels. Complex consequences of panel testing have included an increase in the incidence of identifying variants of uncertain significance and the identification of pathogenic variants in genes for which treatment guidelines are not available. Women diagnosed with breast cancer who carry pathogenic variants in genes with proven associations with breast cancer (BRCA1/2) or highly likely associations (PTEN, PALB2) require additional risk assessment to facilitate treatment decisions that will limit in-breast tumor recurrence and contralateral breast cancer.