Project description:PurposeGerm-line testing for panels of cancer genes using next-generation sequencing is becoming more common in clinical care. We report our experience as a clinical laboratory testing both well-established, high-risk cancer genes (e.g., BRCA1/2, MLH1, MSH2) as well as more recently identified cancer genes (e.g., PALB2, BRIP1), many of which have increased but less well-defined penetrance.MethodsClinical genetic testing was performed on over 10,000 consecutive cases referred for evaluation of germ-line cancer genes, and results were analyzed for frequency of pathogenic or likely pathogenic variants, and were stratified by testing panel, gene, and clinical history.ResultsOverall, a molecular diagnosis was made in 9.0% of patients tested, with the highest yield in the Lynch syndrome/colorectal cancer panel. In patients with breast, ovarian, or colon/stomach cancer, positive yields were 9.7, 13.4, and 14.8%, respectively. Approximately half of the pathogenic variants identified in patients with breast or ovarian cancer were in genes other than BRCA1/2.ConclusionThe high frequency of positive results in a wide range of cancer genes, including those of high penetrance and with clinical care guidelines, underscores both the genetic heterogeneity of hereditary cancer and the usefulness of multigene panels over genetic tests of one or two genes.Genet Med 18 8, 823-832.
Project description:Family history is an important factor in determining hereditary cancer risk for many cancer types. The emergence of next-generation sequencing (NGS) has expedited the discovery of many hereditary cancer susceptibility genes and the development of rapid, affordable testing kits. Here, a 30-gene targeted NGS panel for hereditary cancer risk assessment was tested and validated in a Saudi Arabian population. A total of 310 subjects were screened, including 57 non-cancer patients, 110 index patients with cancer and 143 of the cancer patients' family members, 16 of which also had cancer. Of the 310 subjects, 119 (38.4%) were carriers of pathogenic or likely pathogenic variants (PVs) affecting one or more of the following genes: TP53, ATM, CHEK2, CDH1, CDKN2A, BRCA1, BRCA2, PALB2, BRIP1, RAD51D, APC, MLH1, MSH2, MSH6, PMS2, PTEN, NBN/NBS1 and MUTYH. Among 126 patients and relatives with a history of cancer, 49 (38.9%) were carriers of PVs or likely PVs. Two variants in particular were significantly associated with the occurrence of a specific cancer in this population (APC c.3920T>A - colorectal cancer/Lynch syndrome (p = 0.026); TP53 c.868C>T; - multiple colon polyposis (p = 0.048)). Diverse variants in BRCA2, the majority of which have not previously been reported as pathogenic, were found at higher frequency in those with a history of cancer than in the general patient population. There was a higher background prevalence of genetic variants linked to familial cancers in this cohort than expected based on prevalence in other populations.
Project description:IntroductionRASopathies include disorders generally characterized by developmental delay, specific heart defects, short stature, cardiac hypertrophy, and facial dysmorphisms. Next-generation sequencing (NGS)-based panels have widespread acceptance as a diagnostic tool for RASopathies.Materials and methodsThe first 126 patients evaluated by clinical examination and the NGS RASopathy panel at the Children's Hospital of Philadelphia were enrolled. We calculated diagnosis rate, correlated reported clinical findings with positive or negative test results, and identified final molecular diagnoses in 28/96 patients who tested negative for RASopathies.ResultsTwenty-four patients had pathogenic variants on the RASopathy panel, for a diagnostic yield of 19%. Reported features of pulmonic stenosis and ptosis were significantly correlated with a positive test result; no reported features were significantly correlated with a negative test result. We identified 27 different alternative diagnoses for patients originally suspected of having RASopathies.DiscussionThis study provides information that can assist in guiding differential diagnosis and genetic testing for patients suspected of having a RASopathy disorder.Genet Med advance online publication 20 October 2016.
Project description:BackgroundIn this article, we delineate a loosely selected cohort comprising patients with a history of early-onset breast cancer and/or a familial occurrence of cancer. The aim of this study was to gain insights into the presence of breast cancer-related gene variants in a population from a micro-region in southern Brazil, specifically the Metropolitan Region of Curitiba. This area exhibits a highly genetically mixed population, mirroring the general characteristics of the Brazilian people.MethodsComprehensive next-generation sequencing (NGS) multigene panel testing was conducted on 12 patients from the region, utilizing three different library preparation methods.ResultsTwo pathogenic variants and one candidate pathogenic variant were identified: BRCA2 c.8878C>T, p.Gln2960Ter; CHEK2 c.1100del, p.Thr367Metfs15, and BRCA2 c.3482dup, p.Asp1161Glufs3.ConclusionBRCA2 c.3482dup, a novel candidate pathogenic variant, previously unpublished, is reported. The prevalence of pathogenic variants in this small cohort is similar to that described in the literature. All different library preparation methods were equally proficient in enabling the detection of these variants.
Project description:BACKGROUND:Hereditary breast and ovarian cancer syndrome (HBOC) is caused by pathogenic variants in BRCA and other cancer-related genes. We analyzed variants in BRCA gene and other cancer-related genes in HBOC patients to evaluate the clinical validity of next-generation sequencing (NGS) multi-gene panel testing. METHODS:The BRCA1/2 NGS testing was conducted for 262 HBOC patients. Multiplex ligation-dependent probe amplification and direct Sanger sequencing were performed for confirmation. Multi-gene panel testing was conducted for 120 patients who did not possess BRCA1/2 pathogenic variants but met the National Comprehensive Cancer Network criteria. RESULTS:Pathogenic variants in BRCA1/2 were detected in 30 HBOC patients (11.5%). Additionally, four out of the 120 patients possessed pathogenic variants by multi-gene panel testing (3.3%): MSH2 (c.256G>T, p.Glu86*), PMS2 (c.1687C>T, p.Arg563*), CHEK2 (c.546C>A, p.Tyr182*), and PALB2 (c.3351-1G>C). All the four patients had a family history of cancer. CONCLUSIONS:Multi-gene panel testing could be a significant screening tool for HBOC patients, especially for those with a family history of cancer.
Project description:The management of melanoma has evolved owing to improved understanding of its molecular drivers. To augment the current understanding of the prevalence, patterns, and associations of mutations in this disease, the results of clinical testing of 699 advanced melanoma patients using a pan-cancer next-generation sequencing (NGS) panel of hotspot regions in 46 genes were reviewed. Mutations were identified in 43 of the 46 genes on the panel. The most common mutations were BRAFV600 (36%), NRAS (21%), TP53 (16%), BRAFNon-V600 (6%), and KIT (4%). Approximately one-third of melanomas had >1 mutation detected, and the number of mutations per tumor was associated with melanoma subtype. Concurrent TP53 mutations were the most frequent events in tumors with BRAFV600 and NRAS mutations. Melanomas with BRAFNon-V600mutations frequently harbored concurrent NRAS mutations (18%), which were rare in tumors with BRAFV600 mutations (1.6%). The prevalence of BRAFV600 and KIT mutations were significantly associated with melanoma subtypes, and BRAFV600 and TP53 mutations were significantly associated with cutaneous primary tumor location. Multiple potential therapeutic targets were identified in metastatic unknown primary and cutaneous melanomas that lacked BRAFV600 and NRAS mutations. These results enrich our understanding of the patterns and clinical associations of oncogenic mutations in melanoma.
Project description:BackgroundPathogenic germline mutations in BRCA1/2 constitute the majority of hereditary breast and/or ovarian cancers worldwide. Incidence and mortality rate of breast and ovarian cancers in Pakistani women is high. Thus, to establish the diagnosis for targeted therapy in Pakistan, we conducted Next-generation sequencing-based germline testing for the detection of BRCA1/2 oncogenic variants associated with breast and ovarian cancer subtype.MethodsPeripheral blood of 24 women, diagnosed with breast and epithelial ovarian cancers, was taken from the recruited cases with the consent of performing germline genetic testing. DNA was isolated from the peripheral blood and subjected to indexed BRCA Panel libraries. Targeted NGS was performed for all coding regions and splicing sites of BRCA1 and BRCA2 genes using AmpliSeq for Illumina BRCA Panel and Illumina MiSeq sequencer (placed at AFIP). Analysis of the sequencing results has been done by using Illumina bioinformatics tools.ResultsWe detected 421 variants having a quality score of 100 in all cases under study. The list of identified variants in BRCA1 and BRCA2 genes was narrowed down after filtering out those which did not pass q30 and those with a minor allele frequency (MAF) > 0.05 based on gnomAD browser. To classify these variants, clinical significance was predicted using external curated databases. As a result, we interpreted (n = 4) 16.7% pathogenic variants in BRCA1 and (n = 6) 25% variants of uncertain significance (VUS) in both genes. Descriptive statistics depicted that the age and BMI of BRCA positive cases are less than BRCA negative cases.ConclusionOur findings exhibit an initial report for the NGS based cancer genetic testing in Pakistan. This will enable us to pursue screening and diagnosis of hereditary BRCA mutation utilizing the latest state-of-the-art technique locally available in Pakistan ultimately resulting in targeted cancer therapy.
Project description:In this article, we delineate a loosely selected cohort comprising patients with a history of early-onset breast cancer and/or a familial occurrence of cancer. The aim of this study was to gain insights into the presence of breast cancer-related gene variants in a population from a micro-region in southern Brazil, specifically the Metropolitan Region of Curitiba. This area exhibits a highly genetically mixed population, mirroring the general characteristics of the Brazilian people. Comprehensive next-generation sequencing (NGS) multigene panel testing was conducted, involving the evaluation of twelve patients. Two pathogenic variants and one candidate pathogenic variant were identified: BRCA2:c.8878C>T, p.Gln2960Ter; CHEK2:c.1100delAG>A, p.Thr367Metfs*15 and BRCA2:c.3482dupG>GA, p.Asp1161Glufs*3, a novel variant, previously unpublished, is reported.
Project description:BackgroundAs next-generation sequencing (NGS) technology matures, various amplicon-based NGS tests for BRCA1/2 genotyping have been introduced. This study was designed to evaluate an NGS test using a newly released amplicon-based panel, AmpliSeq for Illumina BRCA Panel (AmpliSeq panel), for detection of clinically significant BRCA variants, and to compare it to another amplicon-based NGS test confirmed by Sanger sequencing.MethodsWe reviewed BRCA test results done by NGS using the TruSeq Custom Amplicon kit from patients suspected of hereditary breast/ovarian cancer syndrome (HBOC) in 2018. Of those, 96 residual samples with 100 clinically significant variants were included in this study using predefined criteria: 100 variants were distributed throughout the BRCA1 and BRCA2 genes. All target variants were confirmed by Sanger sequencing. Duplicate NGS testing of these samples was performed using the AmpliSeq panel, and the concordance of results from the two amplicon-based NGS tests was assessed.ResultsNinety-nine of 100 variants were detected in duplicate BRCA1/2 genotyping using the AmpliSeq panel (sensitivity, 99%; specificity, 100%). In the discordant case, one variant (BRCA1 c.3627dupA) was found only in repeat 1, but not in repeat 2. Automated nomenclature of all variants, except for two indel variants, was in consensus with Human Genome Variation Society nomenclature.ConclusionOur findings confirm that the analytic performance of the AmpliSeq panel is satisfactory, with high sensitivity and specificity.
Project description:IntroductionThe molecular diagnosis of mitochondrial disorders is complicated by phenotypic variability, genetic heterogeneity, and the complexity of mitochondrial heteroplasmy. Next-generation sequencing (NGS) of the mitochondrial genome in combination with a targeted panel of nuclear genes associated with mitochondrial disease provides the highest likelihood of obtaining a comprehensive molecular diagnosis. To assess the clinical utility of this approach, we describe the results from a retrospective review of patients having dual genome panel testing for mitochondrial disease.MethodsDual genome panel testing by NGS was performed on a cohort of 1,509 unrelated affected individuals with suspected mitochondrial disorders. This test included 163 nuclear genes associated with mitochondrial diseases and the entire mitochondrial genome. A retrospective review was performed to evaluate diagnostic yield, disease-gene contributions, and heteroplasmy levels of pathogenic/likely pathogenic (P/LP) mitochondrial DNA (mtDNA) variants.ResultsThe overall diagnostic yield was 14.6%, with 7.7% from the nuclear genome and 6.9% from the mtDNA genome. P/LP variants in nuclear genes were enriched in both well-established genes (e.g., POLG) and more recently described genes (e.g., FBXL4), highlighting the importance of keeping the panel design updated.ConclusionVariants in nuclear and mitochondrial genomes equally contributed to a 14.6% diagnostic yield in this patient cohort. Dual genome NGS testing provides a comprehensive framework for diagnosing mitochondrial disorders, offering clinical utility that can be considered as first-tier approach compared to single genome testing. Characterizing disease-causing genes, variants, and mtDNA heteroplasmy enhances understanding of mitochondrial disorders. Testing alternative tissues can further increase diagnostic yield.