Family Studies for Classification of Variants of Uncertain Classification: Current Laboratory Clinical Practice and a New Web-Based Educational Tool

Interpretation and classification of FBN1 variants associated with Marfan syndrome: consensus recommendations from the Clinical Genome Resource's FBN1 variant curation expert panel

BACKGROUND

In 2015, the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) developed standardized variant curation guidelines for Mendelian disorders. Although these guidelines have been widely adopted, they are not gene- or disease-specific. To mitigate classification discrepancies, the Clinical Genome Resource FBN1 variant curation expert panel (VCEP) was established in 2018 to develop adaptations to the ACMG/AMP criteria for FBN1 in association with Marfan syndrome.

METHODS

The specific recommendations were developed through literature review, surveys, online expert panel discussions, and pilot testing of a set of 60 different variants. Consensus among experts was considered reached if at least 75% of the members agreed with a given rule specification. The final set of rules received approval from the ClinGen Sequence Variant Interpretation Working Group.

RESULTS

The developed specifications introduce modifications to 14 of the 28 ACMG/AMP evidence criteria and deem 6 criteria non-applicable. Some of these specifications include refining the minor allele frequency thresholds, creating a FBN1-specific flowchart for PVS1, defining functional domains of the protein, developing a point-based system of counting probands and instances of de novo occurrences, recommending a points-based method of accounting for family segregation data, and clarifying the applicable functional assays that should be considered. To date, this VCEP has curated 120 variants which have been deposited to ClinVar with the 3-star review status.

CONCLUSIONS

Establishing specific adaptations for FBN1 has provided a framework to foster greater classification concordance among clinical laboratories, ultimately improving clinical care for patients with Marfan syndrome.

The Development and Evaluation of Novel Patient Educational Material for a Variant of Uncertain Significance (VUS) Result in Hereditary Cancer Genes

A Variant of Uncertain Significance (VUS) is a difference in the DNA sequence with uncertain consequences for gene function. A VUS in a hereditary cancer gene should not change medical care, yet some patients undergo medical procedures based on their VUS result, highlighting the unmet educational needs among patients and healthcare providers. To address this need, we developed, evaluated, and refined novel educational materials to explain that while VUS results do not change medical care, it remains important to share any personal or family history of cancer with family members given that their personal and family medical history can guide their cancer risk management. We began by reviewing the prior literature and transcripts from interviews with six individuals with a VUS result to identify content and design considerations to incorporate into educational materials. We then gathered feedback to improve materials via a focus group of multidisciplinary experts and multiple rounds of semi-structured interviews with individuals with a VUS result. Themes for how to improve content, visuals, and usefulness were used to refine the materials. In the final round of interviews with an additional 10 individuals with a VUS result, materials were described as relatable, useful, factual, and easy to navigate, and also increased their understanding of cancer gene VUS results.

Partitioning for Easy Multiplexing: A Versatile Droplet PCR Application for Clone Monitoring in Tumors

Clinical genome-wide next-generation sequencing (NGS) has brought new challenges to genetic laboratories. The identification of numerous patient-specific variants that may require to be screened for on multiple other samples poses an issue when striving for time and cost-effectiveness. Here, we propose d-multiSeq, a straightforward method utilizing the advantages of droplet PCR for multiplexing combined with amplicon-based NGS. By comparing d-multiSeq with a standard multiplex amplicon-based NGS, it was shown that partitioning prevents the amplification competition seen when multiplexing and leads to a homogeneous representation of each target in the total read count for up to a 40-target multiplex without the need for prior adjustment. Variant allele frequency was reliably evaluated with a sensitivity of 97.6% for variant allele frequency up to 1%. The applicability of d-multiSeq was also tested on cell-free DNA with the successful amplification of an eight-target multiplex panel. Preliminary application of the technique to assess the clonal evolution in a childhood leukemia harboring high interpatient variability in its somatic variants is shown. d-multiSeq represents a turnkey solution for analyzing large sets of patient-specific variants on low DNA amounts and cell-free DNA.

Merosin-deficient congenital muscular dystrophy type 1a: detection of LAMA2 variants in Vietnamese patients

Background: Merosin-deficient congenital muscular dystrophy type 1A (MDC1A), also known as laminin-α2 chain-deficient congenital muscular dystrophy (LAMA2-MD), is an autosomal recessive disease caused by biallelic variants in the LAMA2 gene. In MDC1A, laminin- α2 chain expression is absent or significantly reduced, leading to some early-onset clinical symptoms including severe hypotonia, muscle weakness, skeletal deformity, non-ambulation, and respiratory insufficiency. Methods: Six patients from five unrelated Vietnamese families presenting with congenital muscular dystrophy were investigated. Targeted sequencing was performed in the five probands. Sanger sequencing was carried out in their families. Multiplex ligation-dependent probe amplification was performed in one family to examine an exon deletion. Results: Seven variants of the LAMA2 (NM_000426) gene were identified and classified as pathogenic/likely pathogenic variants using American College of Medical Genetics and Genomics criteria. Two of these variants were not reported in the literature, including c.7156-5_7157delinsT and c.8974_8975insTGAT. Sanger sequencing indicated their parents as carriers. The mothers of family 4 and family 5 were pregnant and a prenatal testing was performed. The results showed that the fetus of the family 4 only carries c.4717 + 5G>A in the heterozygous form, while the fetus of the family 5 carries compound heterozygous variants, including a deletion of exon 3 and c.4644C>A. Conclusion: Our findings not only identified the underlying genetic etiology for the patients, but also provided genetic counseling for the parents whenever they have an offspring.

A multicenter study of clinical impact of variant of uncertain significance reclassification in breast, ovarian and colorectal cancer susceptibility genes

BACKGROUND

Clinical interpretation of genetic test results is complicated by variants of uncertain significance (VUS) that have an unknown impact on health but can be clarified through reclassification. There is little empirical evidence regarding VUS reclassification in oncology care settings, including the prevalence and outcomes of reclassification, and racial/ethnic differences.

METHODS

This was a retrospective analysis of persons with and without a personal history of cancer carrying VUS (with or without an accompanying pathogenic or likely pathogenic [P/LP] variant) in breast, ovarian, and colorectal cancer predisposition genes seen at four cancer care settings (in Texas, Florida, Ohio, and New Jersey) between 2013 and 2019.

RESULTS

In 2715 individuals included in the study, 3261 VUS and 313 P/LP variants were reported; 8.1% of all individuals with VUS experienced reclassifications and rates varied significantly among cancer care settings from 4.81% to 20.19% (overall p < 0.001). Compared to their prevalence in the overall sample, reclassification rates for Black individuals were higher (13.6% vs. 19.0%), whereas the rates for Asian individuals were lower (6.3% vs. 3.5%) and rates for White and Hispanic individuals were proportional. Two-year prevalence of VUS reclassification remained steady between 2014 and 2019. Overall, 11.3% of all reclassified VUS resulted in clinically actionable findings and 4.6% subsequently changed individuals' clinical managements.

CONCLUSIONS

The findings from this large multisite study suggest that VUS reclassification alters clinical management, has implications for precision cancer prevention, and highlights the need for implementing practices and solutions for efficiently returning reinterpreted genetic test results.

Next generation sequencing panel target genes: possible diagnostic tool for ectodermal dysplasia related diseases

BACKGROUND

Ectodermal dysplasias (EDs) are a large and complex group of disorders affecting the ectoderm-derived organs; the clinical and genetic heterogeneity of these conditions renders an accurate diagnosis more challenging. The aim of this study is to demonstrate the clinical utility of a targeted resequencing panel through enhancing the molecular and clinical diagnosis of EDs. Given the recent developments in gene and protein-based therapies for X-linked hypohidrotic ectodermal dysplasia, there is a re-emerging interest in identifying the genetic basis of EDs and the respective phenotypic presentations, in an aim to facilitate potential treatments for affected families.

METHODS

We assessed seventeen individuals, from three unrelated families, who presented with diverse phenotypes suggestive of ED. An extensive multidisciplinary clinical evaluation was performed followed by a targeted exome resequencing panel (including genes that are known to cause EDs). MiSeqTM data software was used, variants with Qscore >30 were accepted.

RESULTS

Three different previously reported hemizygous EDA mutations were found in the families. However, a complete genotype-phenotype correlation could not be established, neither in our patients nor in the previously reported patients.

CONCLUSIONS

Targeted exome resequencing can provide a rapid and accurate diagnosis of EDs, while further contributing to the existing ED genetic data. Moreover, the identification of the disease-causing mutation in an affected family is crucial for proper genetic counseling and the establishment of a genotype-phenotype correlation which will subsequently provide the affected individuals with a more suitable treatment plan.

Contribution of Inherited Variants to Hereditary Cancer Syndrome Predisposition

Cancer is a clonal disease that develops as a result of the changes on the genetic material by various factors in micro/macro environment. It has a multi-step development process. In some cancer types, genetic factors allow this multi-step process to proceed easily. These cancer types are also called hereditary cancer syndromes. Targeted gene panels are important diagnostic methods in hereditary cancer syndromes to detect the causative variants associated with these hereditary cancer syndromes. We reviewed the data of 94 patients who applied to Ankara City Hospital Genetic Diseases Evaluation Center from March 2019 to July 2021. Qiagen familial cancer susceptibility gene panel kit was used for next generation sequencing to detect the single nucleotide variants for the targeted genes. Sixty-one genes which are associated with increased cancer risk or well characterized hereditary cancer syndromes were included to this panel. Twenty five patients (27%), including 8 males and 17 females, had pathogenic/likely pathogenic variants in 13 of the 61 genes analyzed. Forty patients (43%) had variants which were assessed as variant of unknown significant. In our study, targeted multi-gene panel was diagnostic in nearly one third of the patients with personal/familial cancer syndromes. Molecular diagnosis in familial cancer syndromes is important in terms of predictive diagnosis and family screening, as well as patient follow-up and early prophylactic surgery. The predisposition for hereditary cancer syndromes can be determined according to pre-test evaluation, figuring out the inheritance type with pedigree analysis, cancer type and the genetic analysis for appropriate susceptibility genes.

Parental segregation study reveals rare benign and likely benign variants in a Brazilian cohort of rare diseases

Genomic studies may generate massive amounts of data, bringing interpretation challenges. Efforts for the differentiation of benign and pathogenic variants gain importance. In this article, we used segregation analysis and other molecular data to reclassify to benign or likely benign several rare clinically curated variants of autosomal dominant inheritance from a cohort of 500 Brazilian patients with rare diseases. This study included only symptomatic patients who had undergone molecular investigation with exome sequencing for suspected diseases of genetic etiology. Variants clinically suspected as the causative etiology and harbored by genes associated with highly-penetrant conditions of autosomal dominant inheritance underwent Sanger confirmation in the proband and inheritance pattern determination because a "de novo" event was expected. Among all 327 variants studied, 321 variants were inherited from asymptomatic parents. Considering segregation analysis, we have reclassified 51 rare variants as benign and 211 as likely benign. In our study, the inheritance of a highly penetrant variant expected to be de novo for pathogenicity assumption was considered as a non-segregation and, therefore, a key step for benign or likely benign classification. Studies like ours may help to identify rare benign variants and improve the correct interpretation of genetic findings.

An Algorithm for Optimal Testing in Co‐segregation Analysis

Clinical genetic sequencing tests often identify variants of uncertain significance. One source of data that can help classify the pathogenicity of variants is familial cosegregation analysis. Identifying and genotyping relatives for cosegregation analysis can be time consuming and costly. We propose an algorithm that describes a single measure of expected variant information gain from genotyping a single additional relative in a family. Then we explore the performance of this algorithm by comparing actual recruitment strategies used in 35 families who had pursued cosegregation analysis with synthetic pedigrees of possible testing outcomes if the families had pursued an optimized testing strategy instead. For each actual and synthetic pedigree, we calculated the likelihood ratio of pathogenicity as each successive test was added to the pedigree. We analyzed the differences in cosegregation likelihood ratio over time resulting from actual versus optimized testing approaches. Employing the testing strategy indicated by the algorithm would have led to maximal information more rapidly in 30 of the 35 pedigrees (86%). Many clinical and research laboratories are involved in targeted cosegregation analysis. The algorithm we present can facilitate a data driven approach to optimal relative recruitment and genotyping for cosegregation analysis and more efficient variant classification.

BRCA1/2 variants of unknown significance in hereditary breast and ovarian cancer (HBOC) syndrome: looking for the hidden meaning

Hereditary breast and ovarian cancer syndrome is caused by germline mutations in BRCA1/2 genes. These genes are very large and their mutations are heterogeneous and scattered throughout the coding sequence. In addition to the above-mentioned mutations, variants of uncertain/unknown significance (VUSs) have been identified in BRCA genes, which make more difficult the clinical management of the patient and risk assessment. In the last decades, several laboratories have developed different databases that contain more than 2000 variants for the two genes and integrated strategies which include multifactorial prediction models based on direct and indirect genetic evidence, to classify the VUS and attribute them a clinical significance associated with a deleterious, high-low or neutral risk. This review provides a comprehensive overview of literature studies concerning the VUSs, in order to assess their impact on the population and provide new insight for the appropriate patient management in clinical practice.

Opinions and experiences of recontacting patients: a survey of Australasian genetic health professionals

The issue of recontacting past genetics patients is increasingly relevant, particularly with the introduction of next-generation sequencing. Improved testing can provide additional information on the pathogenicity and prevalence of genetic variants, often leading to a need to recontact patients. Some international genetics societies have position statements and recommendations to guide genetic health professionals (GHPs) navigating the legal, ethical and practical issues of recontacting. In the absence of a standardised Australasian protocol, we explored the experiences and opinions of Australasian GHPs regarding patient follow-up and recontacting practices. Forty-five respondents completed an online survey. Most respondents indicated that recontacting occurred on an ad hoc basis, but most genetic services relied on patients (or family) initiating recontact. Implementation of a routine recontacting system was widely dismissed by 73% of respondents, citing lack of resources, limited information on legal responsibility and setting unrealistic expectations as common barriers. If recontact was contemplated, e-communication was an acceptable first step. This study identified the need for integrated familial cancer registries to assist under-resourced genetic services to maintain up-to-date patient records. Developing a standard recontacting protocol with flexibility to account for patient individuality and circumstances might enable provision of equitable service within Australasia.

Genome sequencing data analysis for rare disease gene discovery

Rare diseases occur in a smaller proportion of the general population, which is variedly defined as less than 200 000 individuals (US) or in less than 1 in 2000 individuals (Europe). Although rare, they collectively make up to approximately 7000 different disorders, with majority having a genetic origin, and affect roughly 300 million people globally. Most of the patients and their families undergo a long and frustrating diagnostic odyssey. However, advances in the field of genomics have started to facilitate the process of diagnosis, though it is hindered by the difficulty in genome data analysis and interpretation. A major impediment in diagnosis is in the understanding of the diverse approaches, tools and datasets available for variant prioritization, the most important step in the analysis of millions of variants to select a few potential variants. Here we present a review of the latest methodological developments and spectrum of tools available for rare disease genetic variant discovery and recommend appropriate data interpretation methods for variant prioritization. We have categorized the resources based on various steps of the variant interpretation workflow, starting from data processing, variant calling, annotation, filtration and finally prioritization, with a special emphasis on the last two steps. The methods discussed here pertain to elucidating the genetic basis of disease in individual patient cases via trio- or family-based analysis of the genome data. We advocate the use of a combination of tools and datasets and to follow multiple iterative approaches to elucidate the potential causative variant.

Targeted High-Throughput Sequencing Analysis Results of Osteogenesis Imperfecta Patients from Different Regions of Turkey

Objective: Osteogenesis imperfecta (OI) includes a group of disorders characterized by susceptibility to bone fractures with different severities. The increasing number of genes that may underlie the disorder, along with the broad phenotypic spectrum that overlaps with other skeletal diseases, provided a compelling case for the use of high-throughput sequencing (HTS) technology as an aid to OI diagnoses. The aim of this analysis was to present the data from our 5-year targeted HTS results, that includes the reporting of 9 novel and 24 known mutations, found in OI patients, from 5 different regions of Turkey. Materials and Methods: We performed a retrospective cross-sectional study, reporting the HTS results of 43 patients (23 female and 20 male; mean age: 9.5 years), directed to our center with a suspicion of OI between February 2015 and May 2020. Genetic analyses were also performed for 24 asymptomatic parents to aid the segregation analyses. We utilized an HTS panel targeting the coding regions of 57 genes associated with a reduction, increase, or abnormal development of bone mineralization. In addition, we sequenced the entire coding region of the IFITM5 gene through HTS. Results: Thirty-nine patients had at least one pathogenic/likely pathogenic variation (90.69%) in the COL1A1 (56.41%), COL1A2 (20.51%), FKBP10 (7.7%), P3H1 (5.13%), IFITM5 (5.13%), CTRAP (2.56%), or TMEM38B (2.56%) genes. Nine of the determined pathogenic/likely pathogenic variations were novel. The recurrent pathogenic mutations were c.1081C>T (p.Arg361Ter) (3/43), c.1405C>T (p.Arg469Ter) (2/43), and c.3749del (p.Gly1250AlafsTer81) in COL1A1 gene, along with c.-14C>T variation in the 5'UTR of the IFITM5 gene (2/43) and the c.890_897dup variation in the FKBP10 gene (2/43). Three out of 43 patients were carrying at least one additional variant of unknown significance, highlighting the importance of a multigene panel approach and segregation analyses. Conclusion: We suggest that a targeted HTS panel is a feasible tool for genetic diagnosis of OI in patients.

A comprehensive custom panel evaluation for routine hereditary cancer testing: improving the yield of germline mutation detection

Background

In the context of our Regional Program of Hereditary Cancer, individuals fulfilling the criteria are tested for germline mutations to subsequently establish the clinical management. Our standard diagnostic approach focuses on sequencing a few classic high-risk genes, a method that frequently renders uninformative genetic results. This study aims to examine the improved yield offered by an On-Demand panel.

Methods

We designed an On-Demand panel for the analysis of 35-genes associated with inherited cancer susceptibility in a total of 128 cases of Hereditary Breast and Ovarian Cancer (HBOC) and Hereditary Nonpolyposis Colorectal Cancer (HNPCC).

Results

Eighteen deleterious mutations were detected, in both routinely (BRCA2, MLH1, MSH2, PMS2) and non-routinely (ATM, BLM, BRIP1, CHEK2, MUTYH) tested genes. The screening extended to 35 genes rendered by patients carrying several- up to 6-Variants of Unknown Significance (VUS). Moreover, we confirmed the splicing disruption at RNA level for a not previously reported BRIP1 splicing mutation. Using an On-Demand panel, we identified 18 pathogenic mutation carriers, seven of which would have gone unnoticed with traditional analysis.

Conclusions

Our results reinforce the utility of NGS gene panels in the diagnostic routine to increase the performance of genetic testing, especially in individuals from families with overlapping cancer phenotypes.

How I curate: applying American Society of Hematology-Clinical Genome Resource Myeloid Malignancy Variant Curation Expert Panel rules for RUNX1 variant curation for germline predisposition to myeloid malignancies

The broad use of next-generation sequencing and microarray platforms in research and clinical laboratories has led to an increasing appreciation of the role of germline mutations in genes involved in hematopoiesis and lineage differentiation that contribute to myeloid neoplasms. Despite implementation of the American College of Medical Genetics and Genomics and Association for Molecular Pathology 2015 guidelines for sequence variant interpretation, the number of variants deposited in ClinVar, a genomic repository of genotype and phenotype data, and classified as having uncertain significance or being discordantly classified among clinical laboratories remains elevated and contributes to indeterminate or inconsistent patient care. In 2018, the American Society of Hematology and the Clinical Genome Resource co-sponsored the Myeloid Malignancy Variant Curation Expert Panel to develop rules for classifying gene variants associated with germline predisposition to myeloid neoplasia. Herein, we demonstrate application of our rules developed for the RUNX1 gene to variants in six examples to show how we would classify them within the proposed framework.

Proposition of adjustments to the ACMG-AMP framework for the interpretation of MEN1 missense variants

In 2015, the ACMG-AMP guidelines provided a general procedure for the objective and reproducible classification of genomic variants. While the benefits of this framework are of major importance, its adaptation for locus-specific use is needed. Multiple Endocrine Neoplasia type 1 (MEN1) occurs due to inactivating mutations in the tumour suppressor gene MEN1, including 20% of missense variants. The classification of these variants may be extremely challenging. Here, we compared the interpretation of the 122 MEN1 missense variants, identified in the French population over the past 15 years by the TENGEN network (French oncogenetics network of neuroendocrine tumors) versus by using the ACMG-AMP guidelines, and analyzed the causes of discordance. A total of 59.8% of missense variants were termed as (likely)-pathogenic variants by TENGEN versus only 28.7% using ACMG-AMP guidelines. Actually, 53.4% (39/73) of TENGEN (likely)-pathogenic variants were declassified in variant of uncertain significance (VUS) by using ACMG-AMP guidelines, thereby affecting the clinical management of patients and their families. Twenty of these ACMG-AMP VUS were found in patients with a clinically authentic MEN1 disease. Here, TENGEN proposes adjustments to the ACMG-AMP framework for the interpretation of MEN1 missense variants. These propositions merge both the classification systems, and are particularly interesting, as MEN1 is included in the ACMG secondary findings list for reporting in clinical genomic sequencing.

Phenotype to genotype characterization by array-comparative genomic hydridization (a-CGH) in case of fetal malformations: A systematic review

The aim of the current review is to report a-CGH abnormalities identified in fetuses with prenatally diagnosed fetal malformations in whom a normal karyotype was diagnosed with conventional cytogenetic analysis. A systematic electronic search of databases (PubMed/Medline, EMBASE/SCOPUS) has been conducted from inception to May, 2017. Bibliographic analysis has been performed according to PRISMA statement for review. The following keywords were used: 'array-CGH' and 'fetal malformations" and "prenatal diagnosis"; alternatively, "microarray", "oligonucleotide array", "molecular biology", "antenatal diagnostics", "fetal diagnostics", "congenital malformations" and "ultrasound" were used to capture both "a-CGH" and "prenatal". One-hundred and twelve fetuses with prenatally diagnosed fetal malformations with normal karyotyping and a-CGH abnormalities detected are described. Single or multiple microarray abnormalities diagnosed have been classified in relation to different organ/system affected. The most frequent a-CGH abnormalities were detected in cases of congenital heart diseases (CDHs), multiple malformations and central nervous system (CNS) malformations. Maternal or paternal carrier-state was seen in 19.64% (22/112), of cases while the number of reported de novo mutations accounted for 46.42% (52/112) of all CNVs microarray abnormalities. Array-comparative genomic hydridization (a-CGH) may become an integral and complemantary genetic testing when fetal malformations are detected prenatally in fetuses with normal cytogenetic karyotype. In addition, a-CGH enables the identification of CNVs and VOUS and improves the calculation of recurrent risk and the genetic counseling.

Understanding Implementation Challenges to Genetic Testing for Familial Hypercholesterolemia in the United States

Cardiovascular disease (CVD) is the leading cause of death in the United States (US), with familial hypercholesterolemia (FH) being a major inherited and genetic risk factor for premature CVD and atherosclerosis. Genetic testing has helped patients and providers confirm the presence of known pathogenic and likely pathogenic variations in FH-associated genes. Key organizations, such as the Centers for Disease Control and Prevention (CDC), American Heart Association (AHA), FH Foundation, and National Lipid Association (NLA), have recognized the clinical utility of FH genetic testing. However, FH genetic testing is underutilized in clinical practice in the US for reasons that are underexplored through the lens of implementation science. In this commentary, we discuss seven key implementation challenges that must be overcome to strengthen the clinical adoption of FH genetic testing in the US. These implementation challenges center on evidence of cost-effectiveness, navigating patient and provider preferences and concerns, gender and ethnic diversity and representation in genetic testing, and establishing clinical consensus around FH genetic testing based on the latest and most relevant research findings. Overcoming these implementation challenges is imperative to the mission of reducing CVD risk in the US.

Patient goals, motivations, and attitudes in a patient-driven variant reclassification study

Family studies to reclassify clinically ascertained variants of uncertain significance (VUS) can impact risk assessment, medical management, and psychological outcomes for patients and their families. There are limited avenues for patients and their families to actively participate in VUS reclassification, and access to family studies at most commercial laboratories is restricted by multiple factors. To explore patient attitudes about participation in family studies for VUS reclassification, we conducted semistructured pre- and post-participation telephone interviews with 38 participants in a family-based VUS reclassification study that utilized a patient-driven approach for family ascertainment and recruitment. Participants had VUS from multigene panel testing performed at multiple clinical laboratories for cancer or other disease risk. Inductive thematic analysis of transcribed interviews highlighted four major themes: (a) Participants' study goals were driven by the desire to resolve uncertainty related to the VUS, (b) Participants had mixed reactions to the VUS reclassification outcomes of the study, (c) Personal, public, and familial knowledge increased through study participation and (d) Participants used study participation to actively cope with the uncertainty of a VUS. As personalized genomic medicine becomes more prevalent, clinicians, clinical laboratories, and researchers could consider creating more opportunities for active partnership with patients and families, who are motivated to contribute data to familial VUS studies.

Outcomes of 92 patient-driven family studies for reclassification of variants of uncertain significance

PURPOSE

Family studies are an important but underreported source of information for reclassification of variants of uncertain significance (VUS). We evaluated outcomes of a patient-driven framework that offered familial VUS reclassification analysis to any adult with any clinically ascertained VUS from any laboratory in the United States.

METHODS

With guidance from FindMyVariant.org, participants recruited their own relatives for study participation. We genotyped relatives, calculated quantitative cosegregation likelihood ratios, and evaluated variant classifications using Tavtigian's unified framework for Bayesian analysis with American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) criteria. We report participation and VUS reclassification rates from the 50 families enrolled for at least one year and reclassification results for 112 variants from the larger 92-family cohort.

RESULTS

For the 50-family cohort, 6.7 relatives per family were invited to participate and 67% of relatives returned samples for genotyping. Sixty-one percent of VUS were reclassified, 84% of which were classified as benign or likely benign. Genotyping relatives identified a de novo variant, phase variants, and relatives with phenotypes highly specific for or incompatible with specific classifications.

CONCLUSIONS

Motivated families can contribute to successful VUS reclassification at substantially higher rates than those previously published. Clinical laboratories could consider offering family studies to all patients with VUS.

Experiences of patients seeking to participate in variant of uncertain significance reclassification research

Patients' understanding of a genetic variant of unknown clinical significance (VUS) is likely to influence beliefs about risk implications, consequent medical decisions, and other actions such as involvement in research. We interviewed 26 self-selected participants with a clinically identified VUS before they enrolled into a VUS reclassification study. Semi-structured interviews addressed topics including motivation to get genetic test, experience with the VUS result, affective responses to receiving VUS, and perceived effect of VUS and reclassification on medical care. We found that family and personal history of disease were the most prevalent motivators for getting a genetic test. Participants demonstrated mixed understanding of VUS. Most expressed negative effect on learning of their VUS result and uncertainty about its impact on clinical management. Most expected reclassification efforts to benefit their family members but not themselves. Some expressed distrust of their providers following a VUS result. Participation in the VUS reclassification study appeared to be motivated by four factors for patients with VUS-negative effect about VUS, uncertainty about its impact on clinical management, concern for family members' well-being, and to advance science. Perhaps the direct acknowledgement and appraisal of uncertainty as a means of coping was missing in some pre-test counseling experienced by our participants and thus they were not psychologically prepared for atypical VUS results. The finding of VUS-induced provider distrust suggests a need for careful consideration of appropriate pre- and post-test counseling about VUS.

Power of pedigree likelihood analysis in extended pedigrees to classify rare variants of uncertain significance in cancer risk genes

Rare and private variants of uncertain significance (VUS) are routinely identified in clinical panel, exome, and genome sequencing. We investigated the power of single family co-segregation analysis to aid classification of VUS. We simulated thousands of pedigrees using demographics in China and the United States, segregating benign and pathogenic variants. Genotypes and phenotypes were simulated using penetrance models for Lynch syndrome and breast/ovarian cancer. We calculated LOD scores adjusted for proband ascertainment (LODadj), to determine power to yield quantitative evidence for, or against, pathogenicity of the VUS. Power to classify VUS was higher for Chinese than United States pedigrees. The number of affected individuals explained the most variation in LODadj (21-38%). The distance to the furthest affected relative (FAR) from the proband explained 1-7% of the variation for the benign VUS and Lynch associated cancers. Minimum age of onset (MAO) explained 5-13% of the variation in families with pathogenic breast/ovarian cancer variants. Random removal of 50% of the phenotype/genotype data reduced power and the variation in LODadj was best explained by FAR followed by the number of affected individuals and MAO when the founder was only two generations from the proband. Power to classify benign variants was ~2x power to classify pathogenic variants. Affecteds-only analysis resulted in virtually no power to correctly classify benign variants and reduced power to classify pathogenic variants. These results can be used to guide recruitment efforts to classify rare and private VUS.

Identification of twenty-nine novel germline unclassified variants of BRCA1 and BRCA2 genes in 1400 Italian individuals

OBJECTIVES

Breast and/or ovarian cancers are complex multifactorial diseases caused by interaction of both genetic and non-genetic factors and characterized by predisposition to inheritance. BRCA1 and BRCA2 genes are the most clinically involved with these kinds of cancer and the spectrum of variants affecting these genes is very wide. In fact, point variants, large or small insertions/deletions, genomic rearrangements can be found in these patients, although a large number of variants with uncertain biological and clinical significance continues to be identified. Next-generation sequencing (NGS) technology is actually the most powerful tool for the discovering of causative mutations and novel disease genes, moreover it allows to make a rapid diagnosis of genetic variants giving fast, inexpensive and detailed genetic information.

MATERIAL AND METHODS

In this study, we report the screening of BRCA1 and BRCA2 genes on 1400 consecutive Caucasian patients with breast and/or ovarian cancer history or family risk, attending the oncogenetic ambulatory at the Foundation Policlinico Agostino Gemelli in Rome.

RESULTS

We describe twenty-nine novel BRCA1 and BRCA2 variants detected in Italian individuals suffering from hereditary breast and ovarian cancer syndrome (HBOC).

CONCLUSION

Data regarding novel variants can provide useful information not only at epidemiological but also at clinical level, allowing for the better managing of breast and ovarian cancer patients and their family members.

Genetic Testing: Challenges and Changes in Testing for Hereditary Cancer Syndromes

BACKGROUND

The practice of genetic testing for hereditary cancer syndromes has changed dramatically in recent years, and patients often approach oncology nurses requesting information about genetic testing.
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OBJECTIVES

This article aims to explore changes in cancer genetics, the role of genetics professionals in providing comprehensive genetic care, and the implications of these new developments in genetics for oncology nurses.
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METHODS

A literature review was conducted and focused on articles about the updating of genetic tests with panel testing, insurance changes, alternative genetic counseling strategies, and direct-to-consumer genetic testing.
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FINDINGS

Oncology nurses play an important role in identifying and referring patients, including those who have tested negative for hereditary susceptibility genes, to genetics professionals. Genetics professionals can assist with insurance issues, interpretation of test results, clarification when a variant of unknown clinical significance is detected, and recommendations for care based on personal and family history and testing results. Oncology nurses can assist families with understanding the limitations of direct-to-consumer genetic testing.

Family-Specific Variants and the Limits of Human Genetics

Every single-nucleotide change compatible with life is present in the human population today. Understanding these rare human variants defines an extraordinary challenge for genetics and medicine. The new clinical practice of sequencing many genes for hereditary cancer risk has illustrated the utility of clinical next-generation sequencing in adults, identifying more medically actionable variants than single-gene testing. However, it has also revealed a linear relationship between the length of DNA evaluated and the number of rare 'variants of uncertain significance' reported. We propose that careful approaches to phenotype-genotype inference, distinguishing between diagnostic and screening intent, in conjunction with expanded use of family-scale genetics studies as a source of information on family-specific variants, will reduce variants of uncertain significance reported to patients.