scholarly journals Singleton exome sequencing of 90 fetuses with ultrasound anomalies revealing novel disease-causing variants and genotype–phenotype correlations

Author(s):  
Mateja Smogavec ◽  
Maria Gerykova Bujalkova ◽  
Reinhard Lehner ◽  
Jürgen Neesen ◽  
Jana Behunova ◽  
...  

AbstractExome sequencing has been increasingly implemented in prenatal genetic testing for fetuses with morphological abnormalities but normal rapid aneuploidy detection and microarray analysis. We present a retrospective study of 90 fetuses with different abnormal ultrasound findings, in which we employed the singleton exome sequencing (sES; 75 fetuses) or to a lesser extent (15 fetuses) a multigene panel analysis of 6713 genes as a primary tool for the detection of monogenic diseases. The detection rate of pathogenic or likely pathogenic variants in this study was 34.4%. The highest diagnostic rate of 56% was in fetuses with multiple anomalies, followed by cases with skeletal or renal abnormalities (diagnostic rate of 50%, respectively). We report 20 novel disease-causing variants in different known disease-associated genes and new genotype–phenotype associations for the genes KMT2D, MN1, CDK10, and EXOC3L2. Based on our data, we postulate that sES of fetal index cases with a concurrent sampling of parental probes for targeted testing of the origin of detected fetal variants could be a suitable tool to obtain reliable and rapid prenatal results, particularly in situations where a trio analysis is not possible.

Author(s):  
Adam L. Numis ◽  
Gilberto da Gente ◽  
Elliott H. Sherr ◽  
Hannah C. Glass

Abstract Background The contribution of pathogenic gene variants with development of epilepsy after acute symptomatic neonatal seizures is not known. Methods Case–control study of 20 trios in children with a history of acute symptomatic neonatal seizures: 10 with and 10 without post-neonatal epilepsy. We performed whole-exome sequencing (WES) and identified pathogenic de novo, transmitted, and non-transmitted variants from established and candidate epilepsy association genes and correlated prevalence of these variants with epilepsy outcomes. We performed a sensitivity analysis with genes associated with coronary artery disease (CAD). We analyzed variants throughout the exome to evaluate for differential enrichment of functional properties using exploratory KEGG searches. Results Querying 200 established and candidate epilepsy genes, pathogenic variants were identified in 5 children with post-neonatal epilepsy yet in only 1 child without subsequent epilepsy. There was no difference in the number of trios with non-transmitted pathogenic variants in epilepsy or CAD genes. An exploratory KEGG analysis demonstrated a relative enrichment in cell death pathways in children without subsequent epilepsy. Conclusions In this pilot study, children with epilepsy after acute symptomatic neonatal seizures had a higher prevalence of coding variants with a targeted epilepsy gene sequencing analysis compared to those patients without subsequent epilepsy. Impact We performed whole-exome sequencing (WES) in 20 trios, including 10 children with epilepsy and 10 without epilepsy, both after acute symptomatic neonatal seizures. Children with post-neonatal epilepsy had a higher burden of pathogenic variants in epilepsy-associated genes compared to those without post-neonatal epilepsy. Future studies evaluating this association may lead to a better understanding of the risk of epilepsy after acute symptomatic neonatal seizures and elucidate molecular pathways that are dysregulated after brain injury and implicated in epileptogenesis.


Author(s):  
Emily Breidbart ◽  
Liyong Deng ◽  
Patricia Lanzano ◽  
Xiao Fan ◽  
Jiancheng Guo ◽  
...  

Abstract Objectives There have been few large-scale studies utilizing exome sequencing for genetically undiagnosed maturity onset diabetes of the young (MODY), a monogenic form of diabetes that is under-recognized. We describe a cohort of 160 individuals with suspected monogenic diabetes who were genetically assessed for mutations in genes known to cause MODY. Methods We used a tiered testing approach focusing initially on GCK and HNF1A and then expanding to exome sequencing for those individuals without identified mutations in GCK or HNF1A. The average age of onset of hyperglycemia or diabetes diagnosis was 19 years (median 14 years) with an average HbA1C of 7.1%. Results Sixty (37.5%) probands had heterozygous likely pathogenic/pathogenic variants in one of the MODY genes, 90% of which were in GCK or HNF1A. Less frequently, mutations were identified in PDX1, HNF4A, HNF1B, and KCNJ11. For those probands with available family members, 100% of the variants segregated with diabetes in the family. Cascade genetic testing in families identified 75 additional family members with a familial MODY mutation. Conclusions Our study is one of the largest and most ethnically diverse studies using exome sequencing to assess MODY genes. Tiered testing is an effective strategy to genetically diagnose atypical diabetes, and familial cascade genetic testing identified on average one additional family member with monogenic diabetes for each mutation identified in a proband.


2021 ◽  
pp. jmedgenet-2020-107369
Author(s):  
Quentin Thomas ◽  
Antonio Vitobello ◽  
Frederic Tran Mau-Them ◽  
Yannis Duffourd ◽  
Agnès Fromont ◽  
...  

ObjectiveTo assess the efficiency and relevance of clinical exome sequencing (cES) as a first-tier or second-tier test for the diagnosis of progressive neurological disorders in the daily practice of Neurology and Genetic Departments.MethodsSixty-seven probands with various progressive neurological disorders (cerebellar ataxias, neuromuscular disorders, spastic paraplegias, movement disorders and individuals with complex phenotypes labelled ‘other’) were recruited over a 4-year period regardless of their age, gender, familial history and clinical framework. Individuals could have had prior genetic tests as long as it was not cES. cES was performed in a proband-only (60/67) or trio (7/67) strategy depending on available samples and was analysed with an in-house pipeline including software for CNV and mitochondrial-DNA variant detection.ResultsIn 29/67 individuals, cES identified clearly pathogenic variants leading to a 43% positive yield. When performed as a first-tier test, cES identified pathogenic variants for 53% of individuals (10/19). Difficult cases were solved including double diagnoses within a kindred or identification of a neurodegeneration with brain iron accumulation in a patient with encephalopathy of suspected mitochondrial origin.ConclusionThis study shows that cES is a powerful tool for the daily practice of neurogenetics offering an efficient (43%) and appropriate approach for clinically and genetically complex and heterogeneous disorders.


Diagnostics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 142
Author(s):  
Anca Maria Panaitescu ◽  
Simona Duta ◽  
Nicolae Gica ◽  
Radu Botezatu ◽  
Florina Nedelea ◽  
...  

Cornelia de Lange syndrome (CDLS) is caused by pathogenic variants in genes which are structural or regulatory components of the cohesin complex. The classical Cornelia de Lange (CDLS) phenotype is characterized by distinctive facial features, growth retardation, upper limb reduction defects, hirsutism, and developmental delay. Non-classical phenotypes make this condition heterogeneous. Although CDLS is a heterogeneous clinical and genetic condition, clear diagnostic criteria have been described by specialist consensus. Many of these criteria refer to features that can be seen on prenatal ultrasound. The aim of this paper is twofold: to present the ultrasound findings in fetuses affected by CDLS syndrome; to discuss the recent advances and the limitations in the ultrasound and genetic prenatal diagnosis of CDLS. Our review aims to offer, apart from the data needed to understand the genetics and the prenatal presentation of the disease, a joint perspective of the two specialists involved in the prenatal management of this pathology: the fetal medicine specialist and the geneticist. To better illustrate the data presented, we also include a representative clinical case.


Author(s):  
J Fonseca ◽  
C Melo ◽  
C Ferreira ◽  
M Sampaio ◽  
R Sousa ◽  
...  

AbstractEarly infantile epileptic encephalopathy-64 (EIEE 64), also called RHOBTB2-related developmental and epileptic encephalopathy (DEE), is caused by heterozygous pathogenic variants (EIEE 64; MIM#618004) in the Rho-related BTB domain-containing protein 2 (RHOBTB2) gene. To date, only 13 cases with RHOBTB2-related DEE have been reported. We add to the literature the 14th case of EIEE 64, identified by whole exome sequencing, caused by a heterozygous pathogenic variant in RHOBTB2 (c.1531C > T), p.Arg511Trp. This additional case supports the main features of RHOBTB2-related DEE: infantile-onset seizures, severe intellectual disability, impaired motor functions, postnatal microcephaly, recurrent status epilepticus, and hemiparesis after seizures.


2015 ◽  
Vol 3 (4) ◽  
pp. 283-301 ◽  
Author(s):  
Jesse M. Hunter ◽  
Mary Ellen Ahearn ◽  
Christopher D. Balak ◽  
Winnie S. Liang ◽  
Ahmet Kurdoglu ◽  
...  

Author(s):  
Marzia De Bortoli ◽  
Alex V. Postma ◽  
Giulia Poloni ◽  
Martina Calore ◽  
Giovanni Minervini ◽  
...  

2017 ◽  
Vol 97 (1) ◽  
pp. 49-59 ◽  
Author(s):  
N. Dinckan ◽  
R. Du ◽  
L.E. Petty ◽  
Z. Coban-Akdemir ◽  
S.N. Jhangiani ◽  
...  

Tooth agenesis is a common craniofacial abnormality in humans and represents failure to develop 1 or more permanent teeth. Tooth agenesis is complex, and variations in about a dozen genes have been reported as contributing to the etiology. Here, we combined whole-exome sequencing, array-based genotyping, and linkage analysis to identify putative pathogenic variants in candidate disease genes for tooth agenesis in 10 multiplex Turkish families. Novel homozygous and heterozygous variants in LRP6, DKK1, LAMA3, and COL17A1 genes, as well as known variants in WNT10A, were identified as likely pathogenic in isolated tooth agenesis. Novel variants in KREMEN1 were identified as likely pathogenic in 2 families with suspected syndromic tooth agenesis. Variants in more than 1 gene were identified segregating with tooth agenesis in 2 families, suggesting oligogenic inheritance. Structural modeling of missense variants suggests deleterious effects to the encoded proteins. Functional analysis of an indel variant (c.3607+3_6del) in LRP6 suggested that the predicted resulting mRNA is subject to nonsense-mediated decay. Our results support a major role for WNT pathways genes in the etiology of tooth agenesis while revealing new candidate genes. Moreover, oligogenic cosegregation was suggestive for complex inheritance and potentially complex gene product interactions during development, contributing to improved understanding of the genetic etiology of familial tooth agenesis.


Author(s):  
Qingwen Zeng ◽  
Yanjie Fan ◽  
Lili Wang ◽  
Zhuo Huang ◽  
Xuefan Gu ◽  
...  

AbstractBackground:Mucopolysaccharidosis IIIB (MPS IIIB) is a genetic disease characterized by mutations in theCase presentation:Whole exome sequencing (WES) was conducted and the putative pathogenic variants were validated by Sanger sequencing. The activity of MPS IIIB related enzyme in the patient’s blood serum was assayed. A heterozygous, non-synonymous mutation (c.1562C>T, p.P521L) as well as a novel mutation (c.1705C>A, p.Q569K) were found in theConclusions:Our results describe an atypical form of MPS IIIB and illustrate the diagnostic potential of targeted WES in Mendelian disease with unknown etiology. WES could become a powerful tool for molecular diagnosis of MPS IIIB in clinical setting.


2014 ◽  
Author(s):  
Daniel S Himmelstein ◽  
Sergio E Baranzini

The first decade of Genome Wide Association Studies (GWAS) has uncovered a wealth of disease-associated variants. Two important derivations will be the translation of this information into a multiscale understanding of pathogenic variants, and leveraging existing data to increase the power of existing and future studies through prioritization. We explore edge prediction on heterogeneous networks—graphs with multiple node and edge types—for accomplishing both tasks. First we constructed a network with 18 node types—genes, diseases, tissues, pathophysiologies, and 14 MSigDB (molecular signatures database)collections—and 19 edge types from high-throughput publicly-available resources. From this network composed of 40,343 nodes and 1,608,168 edges, we extracted features that describe the topology between specific genes and diseases. Next, we trained a model from GWAS associations and predicted the probability of association between each protein-coding gene and each of 29 well-studied complex diseases. The model, which achieved 132-fold enrichment in precision at 10% recall, outperformed any individual domain, highlighting the benefit of integrative approaches. We identified pleiotropy, transcriptional signatures of perturbations, pathways, and protein interactions as fundamental mechanisms explaining pathogenesis. Our method successfully predicted the results (with AUROC = 0.79) from a withheld multiple sclerosis (MS) GWAS despite starting with only 13 previously associated genes. Finally, we combined our network predictions with statistical evidence of association to propose four novel MS genes, three of which (JAK2, REL, RUNX3) validated on the masked GWAS. Furthermore, our predictions provide biological support highlighting REL as the causal gene within its gene-rich locus. Users can browse all predictions online (http://het.io). Heterogeneous network edge prediction effectively prioritized genetic associations and provides a powerful new approach for data integration across multiple domains.


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