Prevalence and Reclassification of Genetic Variants in South African Populations with Breast Cancer.

Concurrent testing of numerous genes for hereditary breast cancer (BC) is available but can result in management difficulties. We evaluated use of an expanded BC gene panel in women of diverse South African ancestries and assessed use of African genomic data to reclassify variants of uncertain significance (VUS). A total of 331 women of White, Black African, or Mixed Ancestry with BC had a 9-gene panel test, with an additional 75 genes tested in those without a pathogenic/likely pathogenic (P/LP) variant. The proportion of VUS reclassified using ClinGen gene-specific allele frequency (AF) thresholds or an AF > 0.001 in nonguidelines genes in African genomic data was determined. The 9-gene panel identified 58 P/LP variants, but only two of the P/LP variants detected using the 75-gene panel were in confirmed BC genes, resulting in a total of 60 (18.1%) in all participants. P/LP variant prevalence was similar across ancestry groups, but VUS prevalence was higher in Black African and Mixed Ancestry than in White participants. In total, 611 VUS were detected, representing 324 distinct variants. 10.8% (9/83) of VUS met ClinGen AF thresholds in genomic data while 10.8% (26/240) in nonguideline genes had an AF > 0.001. Overall, 27.0% of VUS occurrences could potentially be reclassified using African genomic data. Thus, expanding the gene panel yielded few clinically actionable variants but many VUS, particularly in participants of Black African and Mixed Ancestry. However, use of African genomic data has the potential to reclassify a significant proportion of VUS.

Bayesian meta-analysis of penetrance for cancer risk.

Multi-gene panel testing allows many cancer susceptibility genes to be tested quickly at a lower cost making such testing accessible to a broader population. Thus, more patients carrying pathogenic germline mutations in various cancer-susceptibility genes are being identified. This creates a great opportunity, as well as an urgent need, to counsel these patients about appropriate risk-reducing management strategies. Counseling hinges on accurate estimates of age-specific risks of developing various cancers associated with mutations in a specific gene, ie, penetrance estimation. We propose a meta-analysis approach based on a Bayesian hierarchical random-effects model to obtain penetrance estimates by integrating studies reporting different types of risk measures (eg, penetrance, relative risk, odds ratio) while accounting for the associated uncertainties. After estimating posterior distributions of the parameters via a Markov chain Monte Carlo algorithm, we estimate penetrance and credible intervals. We investigate the proposed method and compare with an existing approach via simulations based on studies reporting risks for two moderate-risk breast cancer susceptibility genes, ATM and PALB2. Our proposed method is far superior in terms of coverage probability of credible intervals and mean square error of estimates. Finally, we apply our method to estimate the penetrance of breast cancer among carriers of pathogenic mutations in the ATM gene.

Clinical practice guidelines for molecular tumor markers, 2nd edition review part 1.

With advances in gene and protein analysis technologies, many target molecules that may be useful in cancer diagnosis have been reported. Therefore, the "Tumor Marker Study Group" was established in 1981 with the aim of "discovering clinically" useful molecules. Later, the name was changed to "Japanese Society for Molecular Tumor Marker Research" in 2000 in response to the remarkable progress in gene-related research. Currently, the world of cancer treatment is shifting from the era of representative tumor markers of each cancer type used for tumor diagnosis and treatment evaluation to the study of companion markers for molecular-targeted therapeutics that target cancer cells. Therefore, the first edition of the Molecular Tumor Marker Guidelines, which summarizes tumor markers and companion markers in each cancer type, was published in 2016. After publication of the first edition, the gene panel testing using next-generation sequencing became available in Japan in June 2019 for insured patients. In addition, immune checkpoint inhibitors have been indicated for a wide range of cancer types. Therefore, the 2nd edition of the Molecular Tumor Marker Guidelines was published in September 2021 to address the need to revise the guidelines. Here, we present an English version of the review (Part 1) of the Molecular Tumor Marker Guidelines, Second Edition.

Genomic medicine advances for brain tumors.

Cancer genome profiling has revealed important genetic alterations that serve as prognostic indicators and guides for treatment decisions, enabling precision medicine. The shift to molecular diagnosis of brain tumors, as reflected in the 2021 World Health Organization Classification of Tumors of the Central Nervous System, is a crucial role for treatment decision-making. This review discusses the significance and role of cancer genome profiling in precision medicine for malignant brain tumors, particularly gliomas. Furthermore, we explore the progress in cancer genome analysis, focusing on cancer gene panel testing, integration of genomic information in brain tumor classification, and hereditary tumors. Additionally, we discuss the transformative effect of genomic medicine on early detection, risk assessment, and precision medicine strategies. The tumor mutational burden in brain tumors is considered low, but the application of molecular targeted drugs, such as isocitrate dehydrogenase inhibitors, v-raf murine sarcoma viral oncogene homolog B1 inhibitors, fibroblast growth factor receptor inhibitors, neurotrophic tyrosine receptor kinase, mechanistic target of rapamycin inhibitors, and anti-programmed death receptor-1 antibody drugs are promising for glioma treatment. We also discuss the future prospects of molecular targeted drugs.

BRCA1 Intragenic Duplication Combined with a Likely Pathogenic TP53 Variant in a Patient with Triple-Negative Breast Cancer: Clinical Risk and Management.

For patients with hereditary breast and ovarian cancer, the probability of carrying two pathogenic variants (PVs) in dominant cancer-predisposing genes is rare. Using targeted next-generation sequencing (NGS), we investigated a 49-year-old Caucasian woman who developed a highly aggressive breast tumor. Our analyses identified an intragenic germline heterozygous duplication in BRCA1 with an additional likely PV in the TP53 gene. The BRCA1 variant was confirmed by multiplex ligation probe amplification (MLPA), and genomic breakpoints were characterized at the nucleotide level (c.135-2578_442-1104dup). mRNA extracted from lymphocytes was amplified by RT-PCR and then Sanger sequenced, revealing a tandem duplication r.135_441dup; p.(Gln148Ilefs*20). This duplication results in the synthesis of a truncated and, most likely, nonfunctional protein. Following functional studies, the TP53 exon 5 c.472C > T; p.(Arg158Cys) missense variant was classified as likely pathogenic by the Li-Fraumeni Syndrome (LFS) working group. This type of unexpected association will be increasingly identified in the future, with the switch from targeted BRCA sequencing to hereditary breast and ovarian cancer (HBOC) panel sequencing, raising the question of how these patients should be managed. It is therefore important to record and investigate these rare double-heterozygous genotypes.

Genetic Causes, Clinical Features, and Survival of Underlying Inborn Errors of Immunity in Omani Patients: a Single-Center Study.

PURPOSE: Early identification of inborn errors of immunity (IEIs) is crucial due to the significant risk of morbidity and mortality. This study aimed to describe the genetic causes, clinical features, and survival rate of IEIs in Omani patients. METHODS: A prospective study of all Omani patients evaluated for immunodeficiency was conducted over a 17-year period. Clinical features and diagnostic immunological findings were recorded. Targeted gene testing was performed in cases of obvious immunodeficiency. For cases with less conclusive phenotypes, a gene panel was performed, followed by whole-exome sequencing if necessary. RESULTS: A total of 185 patients were diagnosed with IEIs during the study period; of these, 60.5% were male. Mean ages at symptom onset and diagnosis were 30.0 and 50.5 months, respectively. Consanguinity and a family history of IEIs were present in 86.9% and 50.8%, respectively. Most patients presented with lower respiratory infections (65.9%), followed by growth and development manifestations (43.2%). Phagocytic defects were the most common cause of IEIs (31.9%), followed by combined immunodeficiency (21.1%). Overall, 109 of 132 patients (82.6%) who underwent genetic testing received a genetic diagnosis, while testing was inconclusive for the remaining 23 patients (17.4%). Among patients with established diagnoses, 37 genes and 44 variants were identified. Autosomal recessive inheritance was present in 81.7% of patients with gene defects. Several variants were novel. Intravenous immunoglobulin therapy was administered to 39.4% of patients and 21.6% received hematopoietic stem cell transplantation. The overall survival rate was 75.1%. CONCLUSION: This study highlights the genetic causes of IEIs in Omani patients. This information may help in the early identification and management of the disease, thereby improving survival and quality of life.

Utility of germline multi-gene panel testing in patients with endometrial cancer.

OBJECTIVES: Patients with germline mutations in mismatch repair genes (MLH1, MSH2, MSH6, PMS2) associated with Lynch syndrome (LS) have an increased lifetime risk of endometrial cancer (EC). Multi-gene panel testing (MGPT) is a recent hereditary cancer risk tool enabling next-generation sequencing of numerous genes in parallel. We determined the prevalence of actionable cancer predisposition gene mutations identified through MGPT in an EC patient cohort. METHODS: A single center retrospective cohort study was conducted of patients with EC who had a clinical indication for genetic testing and who underwent MGPT as part of standard of care treatment between 2012 and 2021. Pathogenic mutations were identified and actionable mutations were defined as those with clinical management implications. Additionally, the number of individuals identified with LS was compared between MGPT and tumor-based screening. RESULTS: The study included a total of 224 patients. Thirty-three patients [14.7%, 95% confidence interval (CI) = 10.4-20.1] had actionable mutations. Twenty-one patients (9.4%, 95% CI = 5.9-14.0) had mutations in LS genes (4 MLH1, 5 MSH2, 7 MSH6, 4 PMS2, 1 Epcam-MSH2). MGPT revealed two patients with LS (9.5% of LS cases) not identified through routine tumor-based screening. Thirteen patients (5.8%, 95% CI = 3.1-9.7) had at least one actionable mutation in a non-Lynch syndrome gene (6 CHEK2, 2 BRCA2, 2 ATM, 2 APC, 1 RAD51C, 1 BRCA1). CONCLUSIONS: Germline MGPT is both feasible and informative as it identifies LS cases not found on tumor testing as well as additional actionable mutations in patients with EC.

Cost-Effectiveness of Tumor Genomic Profiling to Guide First-Line Targeted Therapy Selection in Patients With Metastatic Lung Adenocarcinoma.

OBJECTIVES: A cost-effectiveness analysis comparing comprehensive genomic profiling (CGP) of 10 oncogenes, targeted gene panel testing (TGPT) of 4 oncogenes, and no tumor profiling over the lifetime for patients with metastatic lung adenocarcinoma from the Centers for Medicare and Medicaid Services' perspective was conducted. METHODS: A decision analytic model used 10 000 hypothetical Medicare beneficiaries with metastatic lung adenocarcinoma to simulate outcomes associated with CGP (ALK, BRAF, EGFR, ERBB2, MET, NTRK1, NTRK2, NTRK3, RET, ROS1), TGPT (ALK, BRAF, EGFR, ROS1), and no tumor profiling (no genes tested). First-line targeted cancer-directed therapies were assigned if actionable gene variants were detected; otherwise, nontargeted cancer-directed therapies were assigned. Model inputs were derived from randomized trials (progression-free survival, adverse events), the Veterans Health Administration and Medicare (drug costs), published studies (nondrug cancer-related management costs, health state utilities), and published databases (actionable variant prevalences). Costs (2019 US$) and quality-adjusted life-years (QALYs) were discounted at 3% per year. Probabilistic sensitivity analyses used 1000 Monte Carlo simulations. RESULTS: No tumor profiling was the least costly/person ($122 613 vs $184 063 for TGPT and $188 425 for CGP) and yielded the least QALYs/person (0.53 vs 0.73 for TGPT and 0.74 for CGP). The costs per QALY gained and corresponding 95% confidence interval were $310 735 ($278 323-$347 952) for TGPT vs no tumor profiling and $445 545 ($322 297-$572 084) for CGP vs TGPT. All probabilistic sensitivity analysis simulations for both comparisons surpassed the willingness-to-pay threshold ($150 000 per QALY gained). CONCLUSION: Compared with no tumor profiling in patients with metastatic lung adenocarcinoma, tumor profiling (TGPT, CGP) improves quality-adjusted survival but is not cost-effective.

Present status of germline findings in precision medicine for Japanese cancer patients: issues in the current system.

OBJECTIVE: Since 2019, precision cancer medicine has been covered by national insurance in Japan; however, to date, germline findings have not been fully reported. The aim of this study was to evaluate the current status and raise a problem of germline finding analysis and disclosure in Japanese precision cancer medicine. METHODS: Germline findings of 52 genes were examined in 296 cases with advanced cancer by a case series study. RESULTS: Six (2.0%) cases were examined by the Oncoguide™ NCC Oncopanel with germline testing, but no germline findings were reported. The remaining 290 (98.0%) cases were analyzed by FoundationOne® CDx (tumor-only testing), which recognized 404 pathogenic variants; those of BRCA1/2 were recognized in 16 (5.5%) tumors. Our institutional algorithm suggested 39 candidate germline findings in 34 cases, while the public algorithm listed at least 91 candidate germline findings. Four germline findings had been previously identified (BRCA1: 3 and ATM: 1). Nine of 30 cases with candidate germline findings excluding these known germline findings refused or deferred germline testing. Only 4 of 16 cases that received counseling underwent germline testing, and those 4 revealed 3 germline findings (BRCA2, CDK4 and RAD51C); in total, 8 (2.7%) germline findings were revealed. Reasons for refusing genetic counseling and/or germline testing included extra hospital visits, added expense for germline testing due to limited national insurance coverage, poor patient physical condition and no known family members associated with the possible germline finding. CONCLUSIONS: In current Japanese precision cancer medicine, only a small fraction of the patients undergoes germline testing and demonstrated germline finding. The current results suggested a need for earlier indications for precision cancer medicine, broader insurance coverage and more efficient germline finding prediction algorithms, to increase the number of germline testings and to improve the following managements.

Increased Co-Occurrence of Pathogenic Variants in Hereditary Breast and Ovarian Cancer and Lynch Syndromes: A Consequence of Multigene Panel Genetic Testing?

The probability of carrying two pathogenic variants (PVs) in dominant cancer-predisposing genes for hereditary breast and ovarian cancer and lynch syndromes in the same patient is uncommon, except in populations where founder effects exist. Two breast cancer women that are double heterozygotes (DH) for both BRCA1/BRCA2, one ovarian cancer case DH for BRCA1/RAD51C, and another breast and colorectal cancer who is DH for BRCA2/PMS2 were identified in our cohort. Ages at diagnosis and severity of disease in BRCA1/BRCA2 DH resembled BRCA1 single-carrier features. Similarly, the co-existence of the BRCA2 and PMS2 mutations prompted the development of breast and colorectal cancer in the same patient. The first BRCA1/BRCA2 DH was identified by HA-based and Sanger sequencing (1 of 623 families with BRCA PVs). However, this ratio has increased up to 2.9% (1 DH carrier vs. 103 single PV carriers) since using a custom 35-cancer gene on-demand panel. The type of cancer developed in each DH patient was consistent with the independently inherited condition, and the clinical outcome was no worse than in patients with single BRCA1 mutations. Therefore, the clinical impact, especially in patients with two hereditary syndromes, lies in genetic counseling tailor-made for each family based on the clinical guidelines for each syndrome. The number of DH is expected to be increased in the future as a result of next generation sequencing routines.

WEScover: selection between clinical whole exome sequencing and gene panel testing.

BACKGROUND: Whole exome sequencing (WES) is widely adopted in clinical and research settings; however, one of the practical concerns is the potential false negatives due to incomplete breadth and depth of coverage for several exons in clinically implicated genes. In some cases, a targeted gene panel testing may be a dependable option to ascertain true negatives for genomic variants in known disease-associated genes. We developed a web-based tool to quickly gauge whether all genes of interest would be reliably covered by WES or whether targeted gene panel testing should be considered instead to minimize false negatives in candidate genes. RESULTS: WEScover is a novel web application that provides an intuitive user interface for discovering breadth and depth of coverage across population-scale WES datasets, searching either by phenotype, by targeted gene panel(s) or by gene(s). Moreover, the application shows metrics from the Genome Aggregation Database to provide gene-centric view on breadth of coverage. CONCLUSIONS: WEScover allows users to efficiently query genes and phenotypes for the coverage of associated exons by WES and recommends use of panel tests for the genes with potential incomplete coverage by WES.

The Japanese Society of Pathology Practical Guidelines on the handling of pathological tissue samples for cancer genomic medicine.

Clinical cancer genomic testing based on next-generation sequencing can help select genotype-matched therapy and provide diagnostic and prognostic information. Pathological tissue from malignant tumors obtained during routine practice are frequently used for genomic testing. This article is aimed to standardize the proper handling of pathological specimens in practice for genomic medicine based on the findings established in "Guidelines on the handling of pathological tissue samples for genomic medicine (in Japanese)" published by The Japanese Society of Pathology (JSP) in 2018. The two-part practical guidelines are based on empirical data analyses; Part 1 describes the standard preanalytic operating procedures for tissue collection, processing, and storage of formalin-fixed paraffin-embedded (FFPE) samples, while Part 2 describes the assessment and selection of FFPE samples appropriate for genomic testing, typically conducted by a pathologist. The guidelines recommend that FFPE sample blocks be used within 3 years from preparation, and the tumor content should be ≥30% (minimum 20%). The empirical data were obtained from clinical studies performed by the JSP in collaboration with leading Japanese cancer genome research projects. The Japanese Ministry of Health, Labour, and Welfare (MHLW) recommended to comply with the JSP practical guidelines in implementing cancer genomic testing under the national health insurance system in over 200 MHLW-designated core and cooperative cancer genome medicine hospitals in Japan.

Homologous Recombination Deficiencies and Hereditary Tumors.

Homologous recombination (HR) is a vital process for repairing DNA double-strand breaks. Germline variants in the HR pathway, comprising at least 10 genes, such as BRCA1, BRCA2, ATM, BARD1, BRIP1, CHEK2, NBS1(NBN), PALB2, RAD51C, and RAD51D, lead to inherited susceptibility to specific types of cancers, including those of the breast, ovaries, prostate, and pancreas. The penetrance of germline pathogenic variants of each gene varies, whereas all their associated protein products are indispensable for maintaining a high-fidelity DNA repair system by HR. The present review summarizes the basic molecular mechanisms and components that collectively play a role in maintaining genomic integrity against DNA double-strand damage and their clinical implications on each type of hereditary tumor.

An assessment of the role of vinculin loss of function variants in inherited cardiomyopathy.

The ACMG/AMP variant classification framework was intended for highly penetrant Mendelian conditions. While it is appreciated that clinically relevant variants exhibit a wide spectrum of penetrance, accurately assessing and expressing the pathogenicity of variants with lower penetrance can be challenging. The vinculin (VCL) gene illustrates these challenges. Model organism data provide evidence that loss of function of VCL may play a role in cardiomyopathy and aggregate case-control studies suggest low penetrance. VCL loss of function variants, however, are rarely identified in affected probands and therefore there is a paucity of family studies clarifying the clinical significance of individual variants. This study, which aggregated data from >18,000 individuals who underwent gene panel or exome testing for inherited cardiomyopathies, identified 32 probands with VCL loss-of-function variants and confirmed enrichment in probands with dilated cardiomyopathy (odds ratio [OR] = 9.01; confidence interval [CI] = 4.93-16.45). Our data revealed that the majority of these individuals (89.5%) had pediatric onset of disease. Family studies demonstrated that heterozygous loss of function of VCL alone is insufficient to cause cardiomyopathy but that these variants do contribute to disease risk. In conclusion, VCL loss-of-function variants should be reported in a diagnostic setting but need to be clearly distinguished as having lower penetrance.

Rare germline genetic variants and risk of aggressive prostate cancer.

Few genetic risk factors have been demonstrated to be specifically associated with aggressive prostate cancer (PrCa). Here, we report a case-case study of PrCa comparing the prevalence of germline pathogenic/likely pathogenic (P/LP) genetic variants in 787 men with aggressive disease and 769 with nonaggressive disease. Overall, we observed P/LP variants in 11.4% of men with aggressive PrCa and 9.8% of men with nonaggressive PrCa (two-tailed Fisher's exact tests, P = .28). The proportion of BRCA2 and ATM P/LP variant carriers in men with aggressive PrCa exceeded that observed in men with nonaggressive PrCa; 18/787 carriers (2.3%) and 4/769 carriers (0.5%), P = .004, and 14/787 carriers (0.02%) and 5/769 carriers (0.01%), P = .06, respectively. Our findings contribute to the extensive international effort to interpret the genetic variation identified in genes included on gene-panel tests, for which there is currently an insufficient evidence-base for clinical translation in the context of PrCa risk.

Diagnostic yield of multigene panel testing in an Israeli cohort: enrichment of low-penetrance variants.

BACKGROUND: Carriers of pathogenic variants (PVs) in moderate-high-penetrance cancer susceptibility genes are offered tailored surveillance schemes for early cancer diagnosis. The clinical implications of low-penetrance variant carriers are less clear. METHODS: Clinical and demographic data were retrieved for a cohort of Israeli individuals who underwent oncogenetic testing by the 30-gene cancer panel at Color Genomics laboratory, between 04/2013 and 12/2018. RESULTS: Of 758 genotyped individuals, 504 had been diagnosed with cancer prior to testing: 283 (56%) had breast cancer and 106 (21%) colorectal cancer. Pathogenic or likely pathogenic (P/LP) variants were detected in 123 (16%) individuals. Overall, 44 different P/LP variants were detected in 18/30 cancer susceptibility genes; 20 of them were founder/recurrent mutations. Of the carriers, 39 (32%), 10 (8%), and 74 (60%) carried high-, moderate-, or low-penetrance variants, respectively. After excluding low-penetrance variants, 7% (33/504) of all cancer patients, 6% of breast or ovarian cancer patients were found to be carriers, as well as 7% (14/203) of individuals with colonic polyps, and 4% (11/254) of cancer-free individuals. CONCLUSIONS: The diagnostic yield of moderate- and high-penetrance PVs using multigene panel testing was 6%, with 3.7% carriers of non-recurrent PVs. This yield should be discussed during pre-test counseling, and emphasizes the need for harmonized recommendations regarding clinical implications of low-penetrance variants.

Ancestry-specific hereditary cancer panel yields: Moving toward more personalized risk assessment.

Healthcare disparities in genomic medicine are well described. Despite some improvements, we continue to see fewer individuals of African American, Asian, and Hispanic ancestry undergo genetic counseling and testing compared to those of European ancestry. It is well established that variant of uncertain significance (VUS) rates are higher among non-European ancestral groups undergoing multi-gene hereditary cancer panel testing. However, pathogenic variant (PV) yields, and genomic data in general, are often reported in aggregate and derived from cohorts largely comprised of individuals of European ancestry. We performed a retrospective review of clinical and ancestral data for individuals undergoing multi-gene hereditary cancer panel testing to determine ancestry-specific PV and VUS rates. An ancestry other than European was reported in 29,042/104,851 (27.7%) of individuals. Compared to Europeans (9.4%), individuals of Middle Eastern ancestry were more likely to test positive for one or more pathogenic variants (12.1%, p = .0025), while African Americans were less likely (7.9%, p < .0001). Asian and Middle Eastern individuals were most likely (34.8% and 33.2%, respectively) to receive a report with an overall classification of VUS, while individuals of Ashkenazi Jewish and European ancestry were least likely (17.1% and 20.4%, respectively). These data suggest that in addition to higher VUS rates, there may be ancestry-specific PV yields. Providing aggregate data derived from cohorts saturated with European individuals does not adequately reflect genetic testing outcomes in minority groups, and interrogation of ancestry-specific data is a step toward a more personalized risk assessment.

Dual Deep Sequencing Improves the Accuracy of Low-Frequency Somatic Mutation Detection in Cancer Gene Panel Testing.

Cancer gene panel testing requires accurate detection of somatic mosaic mutations, as the test sample consists of a mixture of cancer cells and normal cells; each minor clone in the tumor also has different somatic mutations. Several studies have shown that the different types of software used for variant calling for next generation sequencing (NGS) can detect low-frequency somatic mutations. However, the accuracy of these somatic variant callers is unknown. We performed cancer gene panel testing in duplicate experiments using three different high-fidelity DNA polymerases in pre-capture amplification steps and analyzed by three different variant callers, Strelka2, Mutect2, and LoFreq. We selected six somatic variants that were detected in both experiments with more than two polymerases and by at least one variant caller. Among them, five single nucleotide variants were verified by CEL nuclease-mediated heteroduplex incision with polyacrylamide gel electrophoresis and silver staining (CHIPS) and Sanger sequencing. In silico analysis indicated that the FBXW7 and MAP3K1 missense mutations cause damage at the protein level. Comparing three somatic variant callers, we found that Strelka2 detected more variants than Mutect2 and LoFreq. We conclude that dual sequencing with Strelka2 analysis is useful for detection of accurate somatic mutations in cancer gene panel testing.

Clinical implications of germline mutations in breast cancer genes: RECQL.

BACKGROUND: The identification of new hereditary breast cancer genes is an area of highly active research. In 2015, two independent studies provided initial evidence for a novel breast cancer susceptibility gene, RECQL, a DNA helicase which plays an important role in the DNA damage response. Several subsequent studies in independent patient cohorts have provided further data on RECQL variant frequency in additional populations, some of which have brought in to question the increased breast cancer risk associated with RECQL mutations. RESULTS: The initial reports present findings from whole exome sequencing of high-risk familial breast cancer cases in the French-Canadian, Polish and Han Chinese populations and estimate the carrier frequency of pathogenic RECQL mutations in high-risk breast cancer patients who have previously tested negative for BRCA1 and BRCA2 mutations to be approximately 1-2%. Proposed founder mutations were identified in French-Canadian and Polish populations. Functional studies support loss of function of the helicase activity of RECQL for some of the reported pathogenic mutations. An additional study in a cohort of Southern Chinese high-risk breast cancer patients estimated the frequency of pathogenic RECQL mutations to be 0.54%. A possible Chinese founder mutation was identified, but only a small number of controls were sequenced. Subsequent case-control studies screening for the Polish founder mutation in patients from Germany and Belarus did not find any evidence for increased breast cancer risk for this variant. An Australian case-control study also failed to identify an increased risk of breast cancer associated with RECQL loss of function variants. CONCLUSIONS: RECQL plays an important role in DNA repair, and is a plausible candidate breast cancer susceptibility gene. Initial studies showed evidence of an association between variants in this gene and an increased breast cancer risk in three separate populations, and identified founder mutations with significantly increased odds ratios. However, several subsequent studies have failed to support the association. With the limited and conflicting evidence available, there remains debate as to whether there is an increased breast cancer risk in individuals carrying RECQL loss of function variants. Further studies are required to better quantify the risks associated with RECQL variants and the current evidence base is not sufficient to justify routine inclusion of RECQL on breast cancer gene panels in clinical use. Management of patients in whom RECQL variants have been identified should be based on clinician assessment, in the context of the family history. Further studies are required to better quantify the risks to RECQL mutation carriers and may also guide management and potential therapeutic targeting for patients.

Pitfalls of clinical exome and gene panel testing: alternative transcripts.

PURPOSE: Clinical exome and gene panel testing can provide molecular diagnoses for patients with rare Mendelian disorders, but for many patients these tests are nonexplanatory. We investigated whether interrogation of alternative transcripts in known disease genes could provide answers for additional patients. METHODS: We integrated alternative transcripts for known neonatal epilepsy genes with RNA-Seq data to identify brain-expressed coding regions that are not evaluated by popular neonatal epilepsy clinical gene panel and exome tests. RESULTS: We found brain-expressed alternative coding regions in 89 (30%) of 292 neonatal epilepsy genes. The 147 regions encompass 15,713 bases that are noncoding in the primary transcripts analyzed by the clinical tests. Alternative coding regions from at least 5 genes carry reported pathogenic variants. Three candidate variants in these regions were identified in public exome data from 337 epilepsy patients. Incorporating alternative transcripts into the analysis of neonatal epilepsy genes in 44 patient genomes identified the pathogenic variant for the epilepsy case and 2 variants of uncertain significance (VUS) among the 43 control cases. CONCLUSION: Assessment of alternative transcripts in exon-based clinical genetic tests, including gene panel, exome, and genome sequencing, may provide diagnoses for patients for whom standard testing is unrevealing, without introducing many VUS.