scholarly journals Diagnostic exome sequencing in non-acquired focal epilepsies highlights a major role of GATOR1 complex genes

2020 ◽  
Vol 57 (9) ◽  
pp. 624-633 ◽  
Author(s):  
Martin Krenn ◽  
Matias Wagner ◽  
Christoph Hotzy ◽  
Elisabeth Graf ◽  
Sandrina Weber ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Rare Variants ◽  
Focal Epilepsy ◽  
Diagnostic Yield ◽  
Mammalian Target Of Rapamycin ◽  
High Rate ◽  
Molecular Heterogeneity ◽  
Pathogenic Variants ◽  
Uncertain Significance

BackgroundThe genetic architecture of non-acquired focal epilepsies (NAFEs) becomes increasingly unravelled using genome-wide sequencing datasets. However, it remains to be determined how this emerging knowledge can be translated into a diagnostic setting. To bridge this gap, we assessed the diagnostic outcomes of exome sequencing (ES) in NAFE.Methods112 deeply phenotyped patients with NAFE were included in the study. Diagnostic ES was performed, followed by a screen to detect variants of uncertain significance (VUSs) in 15 well-established focal epilepsy genes. Explorative gene prioritisation was used to identify possible novel candidate aetiologies with so far limited evidence for NAFE.ResultsES identified pathogenic or likely pathogenic (ie, diagnostic) variants in 13/112 patients (12%) in the genes DEPDC5, NPRL3, GABRG2, SCN1A, PCDH19 and STX1B. Two pathogenic variants were microdeletions involving NPRL3 and PCDH19. Nine of the 13 diagnostic variants (69%) were found in genes of the GATOR1 complex, a potentially druggable target involved in the mammalian target of rapamycin (mTOR) signalling pathway. In addition, 17 VUSs in focal epilepsy genes and 6 rare variants in candidate genes (MTOR, KCNA2, RBFOX1 and SCN3A) were detected. Five patients with reported variants had double hits in different genes, suggesting a possible (oligogenic) role of multiple rare variants.ConclusionThis study underscores the molecular heterogeneity of NAFE with GATOR1 complex genes representing the by far most relevant genetic aetiology known to date. Although the diagnostic yield is lower compared with severe early-onset epilepsies, the high rate of VUSs and candidate variants suggests a further increase in future years.

Whole‐Exome Sequencing of a Saudi Epilepsy Cohort Reveals Association Signals in Known and Potentially Novel Loci

2021 ◽  
Author(s):  
Amein Kadhem AlAli ◽  
Abdulrahman Al-Enazi ◽  
Ahmed Ammar ◽  
Mahmoud Hajj ◽  
Cyril Cyrus ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Rare Variants ◽  
High Rate ◽  
Variants Of Unknown Significance ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Novel Variants ◽  
Unknown Significance ◽  
Rare Genetic Variants

Abstract Background Epilepsy, a serious chronic neurological condition effecting up to 100 million people globally, has clear genetic underpinnings including common and rare variants. In Saudi Arabia the prevalence of epilepsy is high and caused mainly by perinatal and genetic factors. No whole-exome sequencing (WES) studies have been performed to date in Saudi Arabian Epilepsy cohorts. This offers a unique opportunity for the discovery of rare genetic variants impacting this disease as there is a high rate of consanguinity amongst large tribal pedigrees. Results We performed WES on 144 individuals diagnosed with epilepsy, to interrogate known Epilepsy related genes for known and functional novel variants. We also used an American College of Medical Genetics (ACMG) guideline based variant prioritization approach in an attempt to discover putative causative variants. We identified a 32 potentially causative pathogenic variants across 30 different genes in 44/144 (30%) of these Saudi Epilepsy individuals. We also identified 232 variants of unknown significance (VUS) across 101 different genes in 133/144 (92%) subjects. Strong enrichment of variants of likely pathogenicity were observed in previously described epilepsy-associated loci, and a number of putative pathogenic variants in novel loci are also observed. Conclusion Several putative pathogenic variants known to be epilepsy-related loci were identified for the first time in our population, in addition to several potential new loci have been identified which may be prioritized for further investigation.

scholarly journals Insights into Genetic Susceptibility to Melanoma by Gene Panel Testing: Potential Pathogenic Variants in ACD, ATM, BAP1, and POT1

Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1007 ◽  
Author(s):  
Lorenza Pastorino ◽  
Virginia Andreotti ◽  
Bruna Dalmasso ◽  
Irene Vanni ◽  
Giulia Ciccarese ◽  
...  
Keyword(s):  
Rare Variants ◽  
Diagnostic Yield ◽  
Susceptibility Genes ◽  
Gene Panel ◽  
Missing Heritability ◽  
Panel Testing ◽  
Pathogenic Variants ◽  
Gene Panel Testing ◽  
Novel Variants ◽  
Uncertain Significance

The contribution of recently established or candidate susceptibility genes to melanoma missing heritability has yet to be determined. Multigene panel testing could increase diagnostic yield and better define the role of candidate genes. We characterized 273 CDKN2A/ARF and CDK4-negative probands through a custom-designed targeted gene panel that included CDKN2A/ARF, CDK4, ACD, BAP1, MITF, POT1, TERF2IP, ATM, and PALB2. Co-segregation, loss of heterozygosity (LOH)/protein expression analysis, and splicing characterization were performed to improve variant classification. We identified 16 (5.9%) pathogenic and likely pathogenic variants in established high/medium penetrance cutaneous melanoma susceptibility genes (BAP1, POT1, ACD, MITF, and TERF2IP), including two novel variants in BAP1 and 4 in POT1. We also found four deleterious and five likely deleterious variants in ATM (3.3%). Thus, including potentially deleterious variants in ATM increased the diagnostic yield to about 9%. Inclusion of rare variants of uncertain significance would increase the overall detection yield to 14%. At least 10% of melanoma missing heritability may be explained through panel testing in our population. To our knowledge, this is the highest frequency of putative ATM deleterious variants reported in melanoma families, suggesting a possible role in melanoma susceptibility, which needs further investigation.

scholarly journals Whole-exome Sequencing for the Identification of Rare Variants in Primary Immunodeficiency Genes in Children With Sepsis: A Prospective, Population-based Cohort Study

2020 ◽  
Vol 71 (10) ◽  
pp. e614-e623 ◽  
Author(s):  
Alessandro Borghesi ◽  
Johannes Trück ◽  
Samira Asgari ◽  
Vanessa Sancho-Shimizu ◽  
Philipp K A Agyeman ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Rare Variants ◽  
Population Based ◽  
Healthy Children ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Uncertain Significance ◽  
National Cohort ◽  
Pediatric Sepsis

Abstract Background The role of primary immunodeficiencies (PID) in susceptibility to sepsis remains unknown. It is unclear whether children with sepsis benefit from genetic investigations. We hypothesized that sepsis may represent the first manifestation of underlying PID. We applied whole-exome sequencing (WES) to a national cohort of children with sepsis to identify rare, predicted pathogenic variants in PID genes. Methods We conducted a multicenter, population-based, prospective study including previously healthy children aged ≥28 days and <17 years admitted with blood culture-proven sepsis. Using a stringent variant filtering procedure, analysis of WES data was restricted to rare, predicted pathogenic variants in 240 PID genes for which increased susceptibility to bacterial infection has been reported. Results There were 176 children presenting with 185 sepsis episodes who underwent WES (median age, 52 months; interquartile range, 15.4–126.4). There were 41 unique predicted pathogenic PID variants (1 homozygous, 5 hemizygous, and 35 heterozygous) found in 35/176 (20%) patients, including 3/176 (2%) patients carrying variants that were previously reported to lead to PID. The variants occurred in PID genes across all 8 PID categories, as defined by the International Union of Immunological Societies. We did not observe a significant correlation between clinical or laboratory characteristics of patients and the presence or absence of PID variants. Conclusions Applying WES to a population-based cohort of previously healthy children with bacterial sepsis detected variants of uncertain significance in PID genes in 1 out of 5 children. Future studies need to investigate the functional relevance of these variants to determine whether variants in PID genes contribute to pediatric sepsis susceptibility.

scholarly journals Whole Exome Sequencing Analysis in Fetal Skeletal Dysplasia Detected by Ultrasonography: An Analysis of 38 Cases

2021 ◽  
Vol 12 ◽  
Author(s):  
Ying Peng ◽  
Shuting Yang ◽  
Xiaoliang Huang ◽  
Jialun Pang ◽  
Jing Liu ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Diagnostic Yield ◽  
Genetic Disorders ◽  
Recurrence Risk ◽  
Snp Analysis ◽  
Sequencing Analysis ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Uncertain Significance

Background: Skeletal dysplasias (SDs) are a heterogeneous group of genetic disorders that primarily affect bone and cartilage. This study aims to identify the genetic causes for fetal SDs, and evaluates the diagnostic yield of prenatal whole-exome sequencing (WES) for this disorder.Methods: WES was performed on 38 fetuses with sonographically identified SDs and normal results of karyotype and single nucleotide polymorphism (SNP) analysis. Candidate variants were selected by bioinformatics analysis, and verified by Sanger sequencing.Results: WES revealed pathogenic or likely pathogenic variants associated with SDs in 65.79% (25/38) of fetuses, variants of uncertain significance (VUS) in SDs-related genes in 10.53% (4/38) cases, and incidental findings in 31.58% (12/38) fetuses. The SDs-associated variants identified in the present study affected 10 genes, and 35.71% (10/28) of the variants were novel.Conclusion: WES has a high diagnostic rate for prenatal SDs, which improves pregnancy management, prenatal counseling and recurrence risk assessment for future pregnancies. The newly identified variants expanded mutation spectrum of this disorder.

The Spectrum of DEPDC5-Related Epilepsy

2021 ◽  
Author(s):  
Giulia Salomone ◽  
Mattia Comella ◽  
Anna Portale ◽  
Giulia Pecora ◽  
Giuseppe Costanza ◽  
...  
Keyword(s):  
Mammalian Target Of Rapamycin ◽  
High Rate ◽  
Loss Of Function ◽  
Unexpected Death ◽  
Neurodevelopmental Outcomes ◽  
Pathogenic Variants ◽  
Malformation Of Cortical Development ◽  
Uncertain Significance ◽  
Mtorc1 Pathway ◽  
Intrafamilial Variability

AbstractDisheveled EGL-10 and pleckstrin domain-containing protein 5 (DEPDC5) is a key member of the GAP activity toward rags complex 1 complex, which inhibits the mammalian target of rapamycin complex 1 (mTORC1) pathway. DEPDC5 loss-of-function mutations lead to an aberrant activation of the mTOR signaling. At neuronal level, the increased mTOR cascade causes the generation of epileptogenic dysplastic neuronal circuits and it is often associated with malformation of cortical development. The DEPDC5 phenotypic spectrum ranges from sporadic early-onset epilepsies with poor neurodevelopmental outcomes to familial focal epilepsies and sudden unexpected death in epilepsy; a high rate of inter- and intrafamilial variability has been reported. To date, clear genotype–phenotype correlations have not been proven. More studies are required to elucidate the significance of likely pathogenic/variants of uncertain significance. The pursuit of a molecular targeted antiepileptic therapy is a future challenge.

scholarly journals Identification and Classification of Rare Variants in NPC1 and NPC2 in Quebec

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lahoud Touma ◽  
Marjorie Labrecque ◽  
Martine Tetreault ◽  
Antoine Duquette
Keyword(s):  
Exome Sequencing ◽  
Rare Variants ◽  
Variant Calling ◽  
Allelic Frequency ◽  
Healthy Individuals ◽  
Pathogenic Variants ◽  
Niemann Pick Disease ◽  
Novel Variants ◽  
Uncertain Significance ◽  
Niemann Pick

AbstractNiemann–Pick disease type C (NPC) is a treatable autosomal recessive neurodegenerative condition which leads to a variety of progressive manifestations. Despite most cases being diagnosed at a young age, disease prevalence may be underestimated, especially in adults, and interpretation of NPC1 and NPC2 variants can be difficult. This study aims to identify potential pathogenic variants in a large cohort of healthy individuals and classify their risk of pathogenicity to assist with future interpretation of variants. The CARTaGENE (CaG) cohort was used to identify possible variants of NPC1 and NPC2. Nine-hundred and eleven RNA samples and 198 exome sequencing were screened for genetic variants through a bio-informatic pipeline performing alignment and variant calling. The identified variants were analyzed using annotations for allelic frequency, pathogenicity and conservation scores. The ACMG guidelines were used to classify the variants. These were then compared to existing databases and previous studies of NPC prevalence, including the Tübingen NPC database. Thirty-two distinct variants were identified after running the samples in the RNA-sequencing pipeline, two of which were classified as pathogenic and 21 of which were not published previously. Furthermore, 46 variants were both identified in our population and with the Tübingen database, the majority of which were of uncertain significance. Ten additional variants were found in our exome-sequencing sample. This study of a sample from a population living in Quebec demonstrates a variety of rare variants, some of which were already described in the literature as well as some novel variants. Classifying these variants is arduous given the scarcity of available literature, even so in a population of healthy individuals. Yet using this data, we were able to identify two pathogenic variants within our population and several new variants not previously identified.

scholarly journals Exome sequencing in paediatric patients with movement disorders

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Anna Ka-Yee Kwong ◽  
Mandy Ho-Yin Tsang ◽  
Jasmine Lee-Fong Fung ◽  
Christopher Chun-Yu Mak ◽  
Kate Lok-San Chan ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Movement Disorders ◽  
Rare Variants ◽  
Diagnostic Yield ◽  
Neurological Diseases ◽  
Genetic Diagnosis ◽  
Potential Treatment ◽  
Paediatric Patients ◽  
Whole Exome

Abstract Background Movement disorders are a group of heterogeneous neurological diseases including hyperkinetic disorders with unwanted excess movements and hypokinetic disorders with reduction in the degree of movements. The objective of our study is to investigate the genetic etiology of a cohort of paediatric patients with movement disorders by whole exome sequencing and to review the potential treatment implications after a genetic diagnosis. Results We studied a cohort of 31 patients who have paediatric-onset movement disorders with unrevealing etiologies. Whole exome sequencing was performed and rare variants were interrogated for pathogenicity. Genetic diagnoses have been confirmed in 10 patients with disease-causing variants in CTNNB1, SPAST, ATP1A3, PURA, SLC2A1, KMT2B, ACTB, GNAO1 and SPG11. 80% (8/10) of patients with genetic diagnosis have potential treatment implications and treatments have been offered to them. One patient with KMT2B dystonia showed clinical improvement with decrease in dystonia after receiving globus pallidus interna deep brain stimulation. Conclusions A diagnostic yield of 32% (10/31) was reported in our cohort and this allows a better prediction of prognosis and contributes to a more effective clinical management. The study highlights the potential of implementing precision medicine in the patients.

scholarly journals Analysis of Genotype-Phenotype Correlations in Patients With Degenerative Dementia Through the Whole Exome Sequencing

2021 ◽  
Vol 13 ◽  
Author(s):  
Lin Sun ◽  
Jianye Zhang ◽  
Ning Su ◽  
Shaowei Zhang ◽  
Feng Yan ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Clinical Symptoms ◽  
Pathogenic Variants ◽  
Dementia Patients ◽  
Whole Exome ◽  
Uncertain Significance ◽  
Genetic Features ◽  
Standards And Guidelines ◽  
Degenerative Dementia

Background: Sporadic dementias generally occur in older age and are highly polygenic, which indicates some patients transmitted in a poly-genes hereditary fashion.Objective: Our study aimed to analyze the correlations of genetic features with clinical symptoms in patients with degenerative dementia.Methods: We recruited a group of 84 dementia patients and conducted the whole exome sequencing (WES). The data were analyzed focusing on 153 dementia-related causing and susceptible genes.Results: According to the American College of Medical Genetics and Genomics (ACMG) standards and guidelines, we identified four reported pathogenic variants, namely, PSEN1 c.A344G, APP c.G2149A, MAPT c.G1165A, and MAPT c.G742A, one reported likely pathogenic variant, namely, PSEN2 c.G100A, one novel pathogenic variants, SQSTM1 c.C671A, and three novel likely pathogenic variants, namely, ABCA7 c.C4690T, ATP13A2 c.3135delC, and NOS3 c.2897-2A > G. 21 variants with uncertain significance in PSEN2, C9orf72, NOTCH3, ABCA7, ERBB4, GRN, MPO, SETX, SORL1, NEFH, ADCM10, and SORL1, etc., were also detected in patients with Alzheimer’s disease (AD) and frontotemporal dementia (FTD).Conclusion: The new variants in dementia-related genes indicated heterogeneity in pathogenesis and phenotype of degenerative dementia. WES could serve as an efficient diagnostic tool for detecting intractable dementia.

scholarly journals Re-analysis of whole-exome sequencing data uncovers novel diagnostic variants and improves molecular diagnostic yields for sudden death and idiopathic diseases

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Elias L. Salfati ◽  
Emily G. Spencer ◽  
Sarah E. Topol ◽  
Evan D. Muse ◽  
Manuel Rueda ◽  
...  
Keyword(s):  
Sudden Death ◽  
Rare Disease ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Diagnostic Yield ◽  
Molecular Diagnostic ◽  
Sudden Unexplained Death ◽  
Unexplained Death ◽  
Pathogenic Variants ◽  
Whole Exome

Abstract Background Whole-exome sequencing (WES) has become an efficient diagnostic test for patients with likely monogenic conditions such as rare idiopathic diseases or sudden unexplained death. Yet, many cases remain undiagnosed. Here, we report the added diagnostic yield achieved for 101 WES cases re-analyzed 1 to 7 years after initial analysis. Methods Of the 101 WES cases, 51 were rare idiopathic disease cases and 50 were postmortem “molecular autopsy” cases of early sudden unexplained death. Variants considered for reporting were prioritized and classified into three groups: (1) diagnostic variants, pathogenic and likely pathogenic variants in genes known to cause the phenotype of interest; (2) possibly diagnostic variants, possibly pathogenic variants in genes known to cause the phenotype of interest or pathogenic variants in genes possibly causing the phenotype of interest; and (3) variants of uncertain diagnostic significance, potentially deleterious variants in genes possibly causing the phenotype of interest. Results Initial analysis revealed diagnostic variants in 13 rare disease cases (25.4%) and 5 sudden death cases (10%). Re-analysis resulted in the identification of additional diagnostic variants in 3 rare disease cases (5.9%) and 1 sudden unexplained death case (2%), which increased our molecular diagnostic yield to 31.4% and 12%, respectively. Conclusions The basis of new findings ranged from improvement in variant classification tools, updated genetic databases, and updated clinical phenotypes. Our findings highlight the potential for re-analysis to reveal diagnostic variants in cases that remain undiagnosed after initial WES.

scholarly journals Whole-exome sequencing accuracy in the diagnosis of primary ciliary dyskinesia

2020 ◽  
Vol 6 (4) ◽  
pp. 00213-2020
Author(s):  
Alex Gileles-Hillel ◽  
Hagar Mor-Shaked ◽  
David Shoseyov ◽  
Joel Reiter ◽  
Reuven Tsabari ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Primary Ciliary Dyskinesia ◽  
Diagnostic Yield ◽  
Characteristic Curve ◽  
Transmission Electron Microscopy Analysis ◽  
Alternative Diagnosis ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Ciliary Dyskinesia

The diagnosis of primary ciliary dyskinesia (PCD) relies on clinical features and sophisticated studies. The detection of bi-allelic disease-causing variants confirms the diagnosis. However, a standardised genetic panel is not widely available and new disease-causing genes are continuously identified.To assess the accuracy of untargeted whole-exome sequencing (WES) as a diagnostic tool for PCD, patients with symptoms highly suggestive of PCD were consecutively included. Patients underwent measurement of nasal nitric oxide (nNO) levels, ciliary transmission electron microscopy analysis (TEM) and WES. A confirmed PCD diagnosis in symptomatic patients was defined as a recognised ciliary ultrastructural defect on TEM and/or two pathogenic variants in a known PCD-causing gene.Forty-eight patients (46% male) were enrolled, with a median age of 10.0 years (range 1.0–37 years). In 36 patients (75%) a diagnosis of PCD was confirmed, of which 14 (39%) patients had normal TEM. A standalone untargeted WES had a diagnostic yield of 94%, identifying bi-allelic variants in 11 known PCD-causing genes in 34 subjects. A nNO<77 nL·min was nonspecific when including patients younger than 5 years (area under the receiver operating characteristic curve (AUC) 0.75, 95% CI 0.60–0.90). Consecutive WES considerably improved the diagnostic accuracy of nNO in young children (AUC 0.97, 95% CI 0.93–1). Finally, WES established an alternative diagnosis in four patients.In patients with clinically suspected PCD and low nNO levels, WES is a simple, beneficial and accurate next step to confirm the diagnosis of PCD or suggest an alternative diagnosis, especially in preschool-aged children in whom nNO is less specific.

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