scholarly journals Pooled-parent exome sequencing to prioritise de novo variants in genetic disease

2019 ◽  
Author(s):  
Harriet Dashnow ◽  
Katrina M. Bell ◽  
Zornitza Stark ◽  
Tiong Y. Tan ◽  
Susan M. White ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
De Novo ◽  
Diagnostic Yield ◽  
Genetic Disorders ◽  
False Positive Rate ◽  
Standard Of Care ◽  
Recall Rate ◽  
Exome Capture ◽  
Positive Rate ◽  
Sample Pooling

AbstractIn the clinical setting, exome sequencing has become standard-of-care in diagnosing rare genetic disorders, however many patients remain unsolved. Trio sequencing has been demonstrated to produce a higher diagnostic yield than singleton (proband-only) sequencing. Parental sequencing is especially useful when a disease is suspected to be caused by a de novo variant in the proband, because parental data provide a strong filter for the majority of variants that are shared by the proband and their parents. However the additional cost of sequencing the parents makes the trio strategy uneconomical for many clinical situations. With two thirds of the sequencing budget being spent on parents, these are funds that could be used to sequence more probands. For this reason many clinics are reluctant to sequence parents.Here we propose a pooled-parent strategy for exome sequencing of individuals with likely de novo disease. In this strategy, DNA from all the parents of a cohort of unrelated probands is pooled together into a single exome capture and sequencing run. Variants called in the proband can then be filtered if they are also found in the parent pool, resulting in a shorter list of prioritised variants. To evaluate the pooled-parent strategy we performed a series of simulations by combining reads from individual exomes to imitate sample pooling. We assessed the recall and false positive rate and investigated the trade-off between pool size and recall rate. We compared the performance of GATK HaplotypeCaller individual and joint calling, and FreeBayes to genotype pooled samples. Finally, we applied a pooled-parent strategy to a set of real unsolved cases and showed that the parent pool is a powerful filter that is complementary to other commonly used variant filters such as population variant frequencies.

scholarly journals Massively parallel sequencing of the mouse exome to accurately identify rare, induced mutations: an immediate source for thousands of new mouse models

Open Biology ◽  
2012 ◽  
Vol 2 (5) ◽  
pp. 120061 ◽  
Author(s):  
T. D. Andrews ◽  
B. Whittle ◽  
M. A. Field ◽  
B. Balakishnan ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
False Positive ◽  
False Positive Rate ◽  
Massively Parallel ◽  
Exome Capture ◽  
Causative Mutation ◽  
Genetic Screens ◽  
Induced Mutations ◽  
Dna Variants ◽  
Positive Rate

Summary Accurate identification of sparse heterozygous single-nucleotide variants (SNVs) is a critical challenge for identifying the causative mutations in mouse genetic screens, human genetic diseases and cancer. When seeking to identify causal DNA variants that occur at such low rates, they are overwhelmed by false-positive calls that arise from a range of technical and biological sources. We describe a strategy using whole-exome capture, massively parallel DNA sequencing and computational analysis, which identifies with a low false-positive rate the majority of heterozygous and homozygous SNVs arising de novo with a frequency of one nucleotide substitution per megabase in progeny of N -ethyl- N -nitrosourea (ENU)-mutated C57BL/6j mice. We found that by applying a strategy of filtering raw SNV calls against known and platform-specific variants we could call true SNVs with a false-positive rate of 19.4 per cent and an estimated false-negative rate of 21.3 per cent. These error rates are small enough to enable calling a causative mutation from both homozygous and heterozygous candidate mutation lists with little or no further experimental validation. The efficacy of this approach is demonstrated by identifying the causative mutation in the Ptprc gene in a lymphocyte-deficient strain and in 11 other strains with immune disorders or obesity, without the need for meiotic mapping. Exome sequencing of first-generation mutant mice revealed hundreds of unphenotyped protein-changing mutations, 52 per cent of which are predicted to be deleterious, which now become available for breeding and experimental analysis. We show that exome sequencing data alone are sufficient to identify induced mutations. This approach transforms genetic screens in mice, establishes a general strategy for analysing rare DNA variants and opens up a large new source for experimental models of human disease.

dtectDx Breast: A serum biomarker test for breast cancer detection used in conjunction with traditional mammography screening.

2013 ◽  
Vol 31 (26_suppl) ◽  
pp. 18-18
Author(s):  
Meredith C. Henderson ◽  
Keri Sweeten ◽  
Sherri Borman ◽  
Christa Corn ◽  
Lindsey Gordon ◽  
...  
Keyword(s):  
Breast Cancer ◽  
False Positive Rate ◽  
Standard Of Care ◽  
Patient Characteristics ◽  
Protein Biomarkers ◽  
Time Period ◽  
Positive Rate ◽  
Previous Clinical Study

18 Background: Provista Diagnostics has developed a test that analyzes serum concentrations of 5 protein biomarkers in order to detect breast cancer. The dtectDx Breast test utilizes a proprietary algorithm that has been described previously (Weber et al. 2010). In this study, it was noted that the algorithm performs best in women under age 50. The aim of this study was to evaluate the performance characteristics of dtectDx Breast in women under age 50 in a commercial setting and compare the results with data from the previous clinical study. Methods: The dtectDx Breast test measures the concentrations of IL-8, IL-12, VEGF, CEA, and HGF via ELISA. These data combined with select patient characteristics and Provista’s proprietary algorithm result in a test value that is characterized as normal or elevated. dtectDx Breast test reports issued for women under age 50 were reviewed from a 3-year time period and prescribing physicians were interviewed regarding follow-up care and outcome measures (largely imaging studies, if warranted). Results: Of the 908 patients, 8 samples were rejected based on serum quality. Of the remaining 900 patients, 121 were reported as elevated (12.7%). In 4 cases, these elevated results were confirmed cases of breast cancer. Of these, 2 patients initially showed no screening evidence of cancer, but upon further evaluation (after receipt of dtectDx Breast results) were diagnosed with breast cancer. dtectDx correctly identified DCIS 66% of the time (n=2). Conclusions: These results describe the use of dtectDx Breast in a clinical setting and confirm that the assay behaves similarly to previously published results (Weber et al 2010). While the false-positive rate is higher than predicted (12.7% vs 6.8%), the assay correctly identified 4 of 4 invasive cancers and 2 of 3 DCIS cases. Since two of the invasive cancer cases were originally not detected via standard screening procedures, the assay has demonstrated important clinical utility when used in conjunction with mammography/standard of care. Here we show that, in the commercial patient population, when combined with standard of care, dtectDx Breast improves the detection of breast cancer in women under 50.

scholarly journals Detection of de novo copy number deletions from targeted sequencing of trios

2018 ◽  
Author(s):  
Jack M. Fu ◽  
Elizabeth J. Leslie ◽  
Alan F. Scott ◽  
Jeffrey C. Murray ◽  
Mary L. Marazita ◽  
...  
Keyword(s):  
Open Source Software ◽  
Copy Number ◽  
Minimum Distance ◽  
Formal Method ◽  
De Novo ◽  
False Positive Rate ◽  
Targeted Sequencing ◽  
Lower False Positive Rate ◽  
Positive Rate ◽  
Sequencing Platforms

AbstractDe novo copy number deletions have been implicated in many diseases, but there is no formal method to date however that identifies de novo deletions in parent-offspring trios from capture-based sequencing platforms. We developed Minimum Distance for Targeted Sequencing (MDTS) to fill this void. MDTS has similar sensitivity (recall), but a much lower false positive rate compared to less specific CNV callers, resulting in a much higher positive predictive value (precision). MDTS also exhibited much better scalability, and is available as open source software at github.com/JMF47/MDTS.

scholarly journals Pilot study of EVIDENCE: High diagnostic yield and clinical utility of whole exome sequencing using an automated interpretation system for patients with suspected genetic disorders

2019 ◽  
Author(s):  
Go Hun Seo ◽  
Taeho Kim ◽  
Jung-young Park ◽  
Jungsul Lee ◽  
Sehwan Kim ◽  
...  
Keyword(s):  
Family Member ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Diagnostic Yield ◽  
Genetic Disorders ◽  
Genetic Diseases ◽  
Whole Exome ◽  
Interpretation System ◽  
Automated Interpretation ◽  
Age Range

AbstractPurposeEVIDENCE, an automated interpretation system, has been developed to facilitate the entire process of whole exome sequencing (WES) analyses. This study investigated the diagnostic yield of EVIDENCE in patients suspected genetic disorders.MethodsDNA from 330 probands (age range, 0–68 years) with suspected genetic disorders were subjected to WES. Candidate variants were identified by EVIDENCE and confirmed by testing family members and/or clinical reassessments.ResultsThe average number of overlapping organ categories per patient was 4.5 ± 5.0. EVIDENCE reported a total 244 variants in 215 (65.1%) of the 330 probands. After clinical reassessment and/or family member testing, 196 variants were identified in 171 probands (51.8%), including 115 novel variants. These variants were confirmed as being responsible for 146 genetic disorders. One hundred-seven (54.6%) of the 196 variants were categorized as pathogenic or likely pathogenic before, and 146 (74.6%) after, clinical assessment and/or family member testing. Factors associated with a variant being confirmed as causative include rules, such as PVS1, PS1, PM1, PM5, and PP5, and similar symptom scores between that variant and a patient’s phenotype.ConclusionThis new, automated variant interpretation system facilitated the diagnosis of various genetic diseases with a 51% improvement in diagnostic yield.

scholarly journals Whole Exome Sequencing in Neurogenetic Diagnostic Odysseys: An Argentinian Experience

2016 ◽  
Author(s):  
M Córdoba ◽  
SA Rodriguez-Quiroga ◽  
PA Vega ◽  
H Amartino ◽  
C Vázquez-Dusefante ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Low Income ◽  
Clinical Management ◽  
Diagnostic Yield ◽  
Genetic Disorders ◽  
Potential Cost ◽  
Low Income Country ◽  
Whole Exome ◽  
Neurogenetic Disorders

ABSTRACTClinical variability is a hallmark of neurogenetic disorders. They involve widespread neurological entities such as neuropathies, ataxias, myopathies, mitochondrial encephalopathies, leukodystrophies, epilepsy and intellectual disabilities. Despite the use of considerable time and resources, the diagnostic yield in this field has been disappointingly low. This etiologic search has been called a “diagnostic odyssey” for many families. Whole exome sequencing (WES) has proved to be useful across a variety of genetic disorders, simplifying the odyssey of many patients and their families and leading to subsequent changes in clinical management in a proportion of them. Although a diagnostic yield of about 30% in neurogenetic disorders can be extrapolated from the results of large series that have included other medical conditions as well, there are not specific reports assessing its utility in a setting such as ours: a neurogeneticist led academic group serving in a low-income country. Herein, we report on a series of our first 40 consecutive cases that were selected for WES in a research-based neurogenetics laboratory. We demonstrated the clinical utility of WES in our patient cohort, obtaining a diagnostic yield of 40% (95% CI, 24.8%-55.2%), describing cases in which clinical management was altered, and suggesting the potential cost-effectiveness of WES as a single test by examining the number and types of tests that were performed prior to WES which added up to a median cost of $3537.6 ($2892 to $5084) for the diagnostic odysseys experienced by our cohort.

scholarly journals DeNovoCNN: A deep learning approach to de novo variant calling in next generation sequencing data

2021 ◽  
Author(s):  
Gelana Khazeeva ◽  
Karolis Sablauskas ◽  
Bart van der Sanden ◽  
Wouter Steyaert ◽  
Michael Kwint ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
De Novo ◽  
Genetic Disorders ◽  
Variant Calling ◽  
Next Generation Sequencing Data ◽  
Sequencing Data ◽  
Accurate Identification ◽  
Whole Exome ◽  
De Novo Variant ◽  
Generation Sequencing

De novo mutations (DNMs) are an important cause of genetic disorders. The accurate identification of DNMs from sequencing data is therefore fundamental to rare disease research and diagnostics. Unfortunately, identifying reliable DNMs remains a major challenge due to sequence errors, uneven coverage, and mapping artifacts. Here, we developed a deep convolutional neural network (CNN) DNM caller (DeNovoCNN), that encodes alignment of sequence reads for a trio as 160×164 resolution images. DeNovoCNN was trained on DNMs of whole exome sequencing (WES) of 2003 trios achieving on average 99.2% recall and 93.8% precision. We find that DeNovoCNN has increased recall/sensitivity and precision compared to existing de novo calling approaches (GATK, DeNovoGear, Samtools) based on the Genome in a Bottle reference dataset. Sanger validations of DNMs called in both exome and genome datasets confirm that DeNovoCNN outperforms existing methods. Most importantly, we show that DeNovoCNN is robust against different exome sequencing and analyses approaches, thereby allowing it to be applied on other datasets. DeNovoCNN is freely available and can be run on existing alignment (BAM/CRAM) and variant calling (VCF) files from WES and WGS without a need for variant recalling.

scholarly journals P.109 Diagnostic Yield of Targeted Exome Sequencing in West Syndrome

2021 ◽  
Vol 48 (s3) ◽  
pp. S50-S50
Author(s):  
M Parfyonov ◽  
I Guella ◽  
DM Evans ◽  
S Adam ◽  
C DeGuzman ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Genetic Heterogeneity ◽  
High Throughput Sequencing ◽  
De Novo ◽  
Diagnostic Yield ◽  
Genetic Diagnosis ◽  
West Syndrome ◽  
Global Developmental Delay ◽  
Targeted Exome Sequencing ◽  
Ion Proton

Background: West syndrome (WS) is characterized by the onset of epileptic spasms usually within the first year of life. Global developmental delay with/without regression is common. Advances in high-throughput sequencing have supported the genetic heterogeneity of this condition. To better understand the genetic causes of this disorder, we investigated the results of targeted exome sequencing in 29 patients with WS. Methods: Whole exome sequencing (WES) was performed on an Ion ProtonTM and variant reporting was restricted to sequences of 620 known epilepsy genes. Diagnostic yield and treatment impact are described for 29 patients with WS. Results: A definitely/likely diagnosis was made in 10 patients (34%), which included 10 different genes (ALG13, PAFAH1B1, SLC35A2, DYNC1H1, ADSL, DEPDC5, ARX, CDKL5, SCN8A, STXBP1) known to be associated with epilepsy or WS. Most variants were de novo dominant (X-linked/autosomal) except for ARX (X-linked recessive) and ADSL (autosomal recessive). 4 out of 10 (40%) had a genetic diagnosis with potential treatment implications. Conclusions: These results emphasize the genetic heterogeneity of WS. The high diagnostic yield, along with the significant genetic variability, and the potential for treatment impact, supports the early use of this testing in patients with unexplained WS.

Genetic landscape of Rett syndrome-like phenotypes revealed by whole exome sequencing

2019 ◽  
Vol 56 (6) ◽  
pp. 396-407 ◽  
Author(s):  
Kazuhiro Iwama ◽  
Takeshi Mizuguchi ◽  
Eri Takeshita ◽  
Eiji Nakagawa ◽  
Tetsuya Okazaki ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Rett Syndrome ◽  
De Novo ◽  
Diagnostic Yield ◽  
Single Nucleotide Variants ◽  
Serine Threonine Kinase ◽  
Whole Exome ◽  
Genetic Landscape ◽  
Strong Candidate

BackgroundRett syndrome (RTT) is a characteristic neurological disease presenting with regressive loss of neurodevelopmental milestones. Typical RTT is generally caused by abnormality of methyl-CpG binding protein 2 (MECP2). Our objective to investigate the genetic landscape of MECP2-negative typical/atypical RTT and RTT-like phenotypes using whole exome sequencing (WES).MethodsWe performed WES on 77 MECP2-negative patients either with typical RTT (n=11), atypical RTT (n=22) or RTT-like phenotypes (n=44) incompatible with the RTT criteria.ResultsPathogenic or likely pathogenic single-nucleotide variants in 28 known genes were found in 39 of 77 (50.6%) patients. WES-based CNV analysis revealed pathogenic deletions involving six known genes (including MECP2) in 8 of 77 (10.4%) patients. Overall, diagnostic yield was 47 of 77 (61.0 %). Furthermore, strong candidate variants were found in four novel genes: a de novo variant in each of ATPase H+ transporting V0 subunit A1 (ATP6V0A1), ubiquitin-specific peptidase 8 (USP8) and microtubule-associated serine/threonine kinase 3 (MAST3), as well as biallelic variants in nuclear receptor corepressor 2 (NCOR2).ConclusionsOur study provides a new landscape including additional genetic variants contributing to RTT-like phenotypes, highlighting the importance of comprehensive genetic analysis.

Diagnostic yield of clinical exome sequencing as a first-tier genetic test for the diagnosis of genetic disorders in pediatric patients: results from a referral center study

2021 ◽  
Author(s):  
Jean-Philippe Mergnac ◽  
Arnaud Wiedemann ◽  
Céline Chery ◽  
Jean-Marie Ravel ◽  
Farès Namour ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Pediatric Patients ◽  
Genetic Test ◽  
Diagnostic Yield ◽  
Genetic Disorders ◽  
Referral Center ◽  
Clinical Exome Sequencing ◽  
Center Study
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