scholarly journals Phenotypic spectrum and genomics of undiagnosed arthrogryposis multiplex congenita

2021 ◽  
pp. jmedgenet-2020-107595
Author(s):  
Annie Laquerriere ◽  
Dana Jaber ◽  
Emanuela Abiusi ◽  
Jérome Maluenda ◽  
Dan Mejlachowicz ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
De Novo ◽  
Genetic Diagnosis ◽  
Added Value ◽  
Disease Genes ◽  
Arthrogryposis Multiplex Congenita ◽  
Pathogenic Variants ◽  
New Genes ◽  
Whole Exome ◽  
Disease Loci

BackgroundArthrogryposis multiplex congenita (AMC) is characterised by congenital joint contractures in two or more body areas. AMC exhibits wide phenotypic and genetic heterogeneity. Our goals were to improve the genetic diagnosis rates of AMC, to evaluate the added value of whole exome sequencing (WES) compared with targeted exome sequencing (TES) and to identify new genes in 315 unrelated undiagnosed AMC families.MethodsSeveral genomic approaches were used including genetic mapping of disease loci in multiplex or consanguineous families, TES then WES. Sanger sequencing was performed to identify or validate variants.ResultsWe achieved disease gene identification in 52.7% of AMC index patients including nine recently identified genes (CNTNAP1, MAGEL2, ADGRG6, ADCY6, GLDN, LGI4, LMOD3, UNC50 and SCN1A). Moreover, we identified pathogenic variants in ASXL3 and STAC3 expanding the phenotypes associated with these genes. The most frequent cause of AMC was a primary involvement of skeletal muscle (40%) followed by brain (22%). The most frequent mode of inheritance is autosomal recessive (66.3% of patients). In sporadic patients born to non-consanguineous parents (n=60), de novo dominant autosomal or X linked variants were observed in 30 of them (50%).ConclusionNew genes recently identified in AMC represent 21% of causing genes in our cohort. A high proportion of de novo variants were observed indicating that this mechanism plays a prominent part in this developmental disease. Our data showed the added value of WES when compared with TES due to the larger clinical spectrum of some disease genes than initially described and the identification of novel genes.

scholarly journals B.06 Whole exome sequencing in genetic ataxias associated with cerebellar atrophy: the Canadian experience

2019 ◽  
Vol 46 (s1) ◽  
pp. S11
Author(s):  
L Gauquelin ◽  
T Hartley ◽  
M Tarnopolsky ◽  
DA Dyment ◽  
B Brais ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Diagnostic Yield ◽  
Genetic Diseases ◽  
Genetic Diagnosis ◽  
Cerebellar Atrophy ◽  
Clinical Findings ◽  
Disease Genes ◽  
Pathogenic Variants ◽  
Whole Exome

Background: Cerebellar atrophy is characterized by loss of cerebellar tissue, with evidence on brain imaging of enlarged interfolial spaces compared to the foliae. Genetic ataxias associated with cerebellar atrophy are a heterogeneous group of disorders. We investigated the prevalence in Canada and the diagnostic yield of whole exome sequencing (WES) for this group of conditions. Methods: Between 2011 and 2017, WES was performed in 91 participants with cerebellar atrophy as part of one of two national research programs, Finding of Rare Genetic Disease Genes (FORGE) or Enhanced Care for Rare Genetic Diseases in Canada (Care4Rare). Results: A genetic diagnosis was established in 58% of cases (53/91). Pathogenic variants were found in 24 known genes, providing a diagnosis for 46/53 participants (87%), and in four novel genes, accounting for 7/53 cases (13%). 38/91 cases (42%) remained unsolved. The most common diagnoses were channelopathies in 12/53 patients (23%) and mitochondrial disorders in 9/53 (17%). Inheritance was autosomal recessive in the majority of cases. Additional clinical findings provided useful clues to some of the diagnoses. Conclusions: This is the first report on the prevalence of genetic ataxias associated with cerebellar atrophy in Canada, and the utility of WES for this group of conditions.

scholarly journals Whole-exome sequencing with targeted analysis and epilepsy after acute symptomatic neonatal seizures

2021 ◽  
Author(s):  
Adam L. Numis ◽  
Gilberto da Gente ◽  
Elliott H. Sherr ◽  
Hannah C. Glass
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
De Novo ◽  
List Type ◽  
Sequencing Analysis ◽  
Neonatal Seizures ◽  
Pathogenic Variants ◽  
Targeted Analysis ◽  
Whole Exome ◽  
Epilepsy Gene

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.

scholarly journals Whole-Exome Sequencing Identifies Novel Variants for Tooth Agenesis

2017 ◽  
Vol 97 (1) ◽  
pp. 49-59 ◽  
Author(s):  
N. Dinckan ◽  
R. Du ◽  
L.E. Petty ◽  
Z. Coban-Akdemir ◽  
S.N. Jhangiani ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Permanent Teeth ◽  
Tooth Agenesis ◽  
Disease Genes ◽  
Nonsense Mediated Decay ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Novel Variants ◽  
Complex Inheritance

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.

scholarly journals New genes involved in Angelman syndrome-like: expanding the genetic spectrum

2020 ◽  
Author(s):  
Cinthia Aguilera ◽  
Elisabeth Gabau ◽  
Ariadna Ramirez-Mallafré ◽  
Carme Brun-Gasca ◽  
Jana Dominguez-Carral ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Genetic Heterogeneity ◽  
Angelman Syndrome ◽  
De Novo ◽  
System Development ◽  
Neuron System ◽  
Pathogenic Variants ◽  
New Genes ◽  
Whole Exome ◽  
Eeg Abnormalities

AbstractAngelman syndrome (AS) is a neurogenetic disorder characterized by severe developmental delay with absence of speech, happy disposition, frequent laughter, hyperactivity, stereotypies, ataxia and seizures with specific EEG abnormalities. There is a 10-15% of patients with an AS phenotype whose genetic cause remains unknown (Angelman-like syndrome, AS-like). Whole-exome sequencing (WES) was performed on a cohort of 14 patients with clinical features of AS and no molecular diagnosis. As a result, we identified 10 de novo and 1 X-linked pathogenic/likely pathogenic variants in 10 neurodevelopmental genes (SYNGAP1, VAMP2, TBL1XR1, ASXL3, SATB2, SMARCE1, SPTAN1, KCNQ3, SLC6A1 and LAS1L) and one deleterious de novo variant in a candidate gene (HSF2). Our results highlight the wide genetic heterogeneity in AS-like patients and expands the differential diagnosis. New AS-like genes do not interact directly with UBE3A gene product but are involved in synapsis and neuron system development.

scholarly journals Mapping Autosomal Recessive Intellectual Disability: Combined Microarray and Exome Sequencing Identifies 26 Novel Candidate Genes in 192 Consanguineous Families

2016 ◽  
Author(s):  
Ricardo Harripaul ◽  
Nasim Vasli ◽  
Anna Mikhailov ◽  
Muhammad Arshad Rafiq ◽  
Kirti Mittal ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Autosomal Recessive ◽  
De Novo ◽  
Clinical Diagnostics ◽  
High Yield ◽  
Disease Genes ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Whole Exome

Approximately 1% of the global population is affected by intellectual disability (ID), and the majority receive no molecular diagnosis. Previous studies have indicated high levels of genetic heterogeneity, with estimates of more than 2500 autosomal ID genes, the majority of which are autosomal recessive (AR). Here, we combined microarray genotyping, homozygosity-by-descent (HBD) mapping, copy number variation (CNV) analysis, and whole exome sequencing (WES) to identify disease genes/mutations in 192 multiplex Pakistani and Iranian consanguineous families with non-syndromic ID. We identified definite or candidate mutations (or CNVs) in 51% of families in 72 different genes, including 26 not previously reported for ARID. The new ARID genes include nine with loss-of-function mutations(ABI2, MAPK8, MPDZ, PIDD1, SLAIN1, TBC1D23, TRAPPC6B, UBA7,andUSP44),and missense mutations include the first reports of variants inBDNForTET1associated with ID. The genes identified also showed overlap withde novogene sets for other neuropsychiatric disorders. Transcriptional studies showed prominent expression in the prenatal brain. The high yield of AR mutations for ID indicated that this approach has excellent clinical potential and should inform clinical diagnostics, including clinical whole exome and genome sequencing, for populations in which consanguinity is common. As with other AR disorders, the relevance will also apply to outbred populations.

scholarly journals Unravelling the genetic causes of multiple malformation syndromes: A whole exome sequencing study of the Cypriot population

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253562
Author(s):  
Evie Kritioti ◽  
Athina Theodosiou ◽  
Thibaud Parpaite ◽  
Angelos Alexandrou ◽  
Nayia Nicolaou ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Array Cgh ◽  
De Novo ◽  
Genetic Diagnosis ◽  
High Detection Rate ◽  
Whole Exome ◽  
Multiple Malformation ◽  
Family Based ◽  
Malformation Syndromes

Multiple malformation syndromes (MMS) belong to a group of genetic disorders characterised by neurodevelopmental anomalies and congenital malformations. Here we explore for the first time the genetic aetiology of MMS using whole-exome sequencing (WES) in undiagnosed patients from the Greek-Cypriot population after prior extensive diagnostics workup including karyotype and array-CGH. A total of 100 individuals (37 affected), from 32 families were recruited and family-based WES was applied to detect causative single-nucleotide variants (SNVs) and indels. A genetic diagnosis was reported for 16 MMS patients (43.2%), with 10/17 (58.8%) of the findings being novel. All autosomal dominant findings occurred de novo. Functional studies were also performed to elucidate the molecular mechanism relevant to the abnormal phenotypes, in cases where the clinical significance of the findings was unclear. The 17 variants identified in our cohort were located in 14 genes (PCNT, UBE3A, KAT6A, SPR, POMGNT1, PIEZO2, PXDN, KDM6A, PHIP, HECW2, TFAP2A, CNOT3, AGTPBP1 and GAMT). This study has highlighted the efficacy of WES through the high detection rate (43.2%) achieved for a challenging category of undiagnosed patients with MMS compared to other conventional diagnostic testing methods (10–20% for array-CGH and ~3% for G-banding karyotype analysis). As a result, family-based WES could potentially be considered as a first-tier cost effective diagnostic test for patients with MMS that facilitates better patient management, prognosis and offer accurate recurrence risks to the families.

Exome Sequencing Identifies a Novel DES Mutation (R227C) in a Chinese Dilated Cardiomyopathy Family

Cardiology ◽  
2017 ◽  
Vol 137 (2) ◽  
pp. 78-82 ◽  
Author(s):  
Rong Yu ◽  
Lv Liu ◽  
Chan Chen ◽  
Jin-Mei Shen
Keyword(s):  
Dilated Cardiomyopathy ◽  
Exome Sequencing ◽  
Genetic Factors ◽  
Novel Mutation ◽  
Genetic Diagnosis ◽  
Chinese Family ◽  
Common Disease ◽  
Disease Genes ◽  
Whole Exome ◽  
Gene Filtering

Objectives: Dilated cardiomyopathy (DCM) is a common disease in the clinic, and it is the leading cause of heart failure and sudden cardiac death. Previous studies have proven that genetic factors play a crucial role in the occurrence of DCM; more than 50 disease genes including desmin (DES) have been identified to be associated with DCM. At present, most DES mutations are reported in desmin-related myofibrilla myopathy patients, but variants leading to isolated DCM are rarely reported. Methods: We applied whole-exome sequencing and cardiomyopathy-related gene filtering strategies to discover the genetic factors in a Chinese DCM family. Results: A novel mutation (c.679 C>T /p.R227C) in exon 3 of DES was identified and cosegregated with the affected members of a Chinese family with isolated DCM phenotypes (left ventricle and left atrial diameters). Conclusion: This mutation leads to a substitution of arginine by cysteine and it is predicted to be deleterious by bioinformatics programs. Our study not only contributes to the genetic diagnosis and counseling of families with DCM, but it also further proves that DES mutations may lead to isolated DCM and provides a new case for the study of the relationship between DES mutations and DCM.

scholarly journals The Added Value of Whole-Exome Sequencing for Anomalous Fetuses With Detailed Prenatal Ultrasound and Postnatal Phenotype

2021 ◽  
Vol 12 ◽  
Author(s):  
Miao He ◽  
Liu Du ◽  
Hongning Xie ◽  
Lihe Zhang ◽  
Yujun Gu ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Genetic Variants ◽  
Genetic Diagnosis ◽  
Normal Karyotype ◽  
Copy Number Variations ◽  
Prenatal Ultrasound ◽  
Added Value ◽  
Chromosomal Microarray Analysis ◽  
Whole Exome

ObjectivesThe objective of the study was to explore the added value of whole-exome sequencing (WES) in abnormal fetuses with detailed prenatal ultrasound and postnatal phenotype with normal karyotype and chromosomal microarray analysis (CMA).MethodsParents of fetuses with structural abnormalities by prenatal ultrasound who consented to provide fetal samples were prospectively recruited from January 2017 to December 2019. With aneuploidies or cases with copy number variations (CNVs) excluded, WES was performed for cases with normal karyotype and CMA results. Detailed prenatal ultrasound and postnatal imaging or pathology features were recommended for further interpretation of genetic variants.ResultsWES was performed for 94 eligible fetuses, DNA samples of which were extracted from 53 parent–fetus trios and 41 proband-only fetal tissues. A diagnostic genetic variant was identified in 37 (39.4%) of 94 fetuses, and 34 (64.2%) were detected in 53 trios, which was significantly greater than 3 (7.3%) in 41 proband-only cases (p < 0.001). In 34 trios with diagnostic genetic variants, 23 (67.6%) were de novo and 11 (32.4%) were inherited with two homozygous and nine heterozygous variants. Fourteen (14.9%) of 94 fetuses had a variant of uncertain significance (VUS). Among 94 cases, six affected pregnancies continued and 88 terminated, and 57 of 88 terminated cases underwent postmortem examinations. With accurate phenotypes demonstrated by prenatal ultrasound and postnatal autopsies, the clinical phenotypes were correlated in 33 (89.2%) of 37 cases with specific genotypes, with the highest matching ratio in skeletal diseases (20/33, 60.6%).ConclusionWES has added value in the genetic diagnosis of abnormal fetuses with normal karyotypes and CMA, particularly in skeletal diseases. Using WES in various anomalous fetuses can broaden the understanding of prenatal phenotypes and genetic variants.

scholarly journals Spectrum of Movement Disorders in GNAO1 Encephalopathy: in-depth Phenotyping and Literature Review

2020 ◽  
Author(s):  
Soo Yeon Kim ◽  
YoungKyu Shim ◽  
Young Joon Ko ◽  
Soojin Park ◽  
Se Song Jang ◽  
...  
Keyword(s):  
Literature Review ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Epileptic Encephalopathy ◽  
Global Developmental Delay ◽  
Pathogenic Variants ◽  
Whole Exome

Abstract Background GNAO1 encephalopathy is a rare neurodevelopmental disorder characterized by distinct movement presentations and early onset epileptic encephalopathy. Here, we report the in-depth phenotyping of genetically confirmed patients with GNAO1 encephalopathy, focusing on movement presentations. Results Six patients who participated in Korean Undiagnosed Disease Program were diagnosed to have pathogenic or likely pathogenic variants in GNAO1 using whole exome sequencing. All medical records and personal video clips were analyzed with a literature review. Three of the 6 patients were male. Mean follow-up duration was 39 months (range, 7–78 months) and age at last examination was 8.0 years (range, 3.3–16.9 years). Initial complaints were hypotonia or developmental delay in 5 and right-hand clumsiness in 1 patient, which were noticed at 20 months of age on average (range, 0–75 months). All patients showed global developmental delay and 4 had severely retarded development. Five patients (5/6, 83.3%) had many different movement symptoms with various onset and progression. The symptoms included stereotyped hands movement, non-epileptic myoclonus, dyskinesia, dystonia and choreoathetosis. Whole exome sequencing identified 6 different variants in GNAO1. Three were novel de novo variants and atypical presentation was noted in a patient. One variant turned out to be inherited from patient’s mother who had mosaic variant. Distinct phenotypes in patients with variant p.Glu246Lys and p.Arg209His were elucidated by in-depth phenotyping and literature review. Conclusions We reported 6 patients with GNAO1 encephalopathy showing an extremely diverse clinical spectrum on video. Some characteristic movement features identified by careful inspection may also provide important diagnostic insight and practice guidelines.

scholarly journals Spectrum of Movement Disorders in GNAO1 Encephalopathy: In-Depth Phenotyping and Case-by-Case Analysis

2020 ◽  
Author(s):  
Soo Yeon Kim ◽  
YoungKyu Shim ◽  
Young Joon Ko ◽  
Soojin Park ◽  
Se Song Jang ◽  
...  
Keyword(s):  
Literature Review ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Epileptic Encephalopathy ◽  
Global Developmental Delay ◽  
Pathogenic Variants ◽  
Whole Exome

Abstract Background: GNAO1 encephalopathy is a rare neurodevelopmental disorder characterized by distinct movement presentations and early onset epileptic encephalopathy. Here, we report the in-depth phenotyping of genetically confirmed patients with GNAO1 encephalopathy, focusing on movement presentations.Results: Six patients who participated in Korean Undiagnosed Disease Program were diagnosed to have pathogenic or likely pathogenic variants in GNAO1 using whole exome sequencing. All medical records and personal video clips were analyzed with a literature review. Three of the 6 patients were male. Median follow-up duration was 41 months (range, 7–78 months) and age at last examination was 7.4 years (range, 3.3–16.9 years). Initial complaints were hypotonia or developmental delay in 5 and right-hand clumsiness in 1 patient, which were noticed at median age of 3 months (range, 0–75 months). All patients showed global developmental delay and 4 had severely retarded development. Five patients (5/6, 83.3%) had many different movement symptoms with various onset and progression. The symptoms included stereotyped hands movement, non-epileptic myoclonus, dyskinesia, dystonia and choreoathetosis. Whole exome sequencing identified 6 different variants in GNAO1. Three were novel de novo variants and atypical presentation was noted in a patient. One variant turned out to be inherited from patient’s mother who had mosaic variant. Distinct and characteristics movement phenotypes in patients with variant p.Glu246Lys and p.Arg209His were elucidated by in-depth phenotyping and literature review. Conclusions: We reported 6 patients with GNAO1 encephalopathy showing an extremely diverse clinical spectrum on video. Some characteristic movement features identified by careful inspection may also provide important diagnostic insight and practice guidelines.

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