scholarly journals Genomic profiling of 553 uncharacterized neurodevelopment patients reveals a high proportion of recessive pathogenic variant carriers in an outbred population

2019 ◽  
Author(s):  
Youngha Lee ◽  
Soojin Park ◽  
Jin Sook Lee ◽  
Soo Yeon Kim ◽  
Jaeso Cho ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Genetic Diagnosis ◽  
Pathogenic Variant ◽  
Mendelian Disease ◽  
Loss Of Function ◽  
Variant Discovery ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Neurodevelopmental Problems

AbstractBackgroundA substantial portion of Mendelian disease patients suffers from genetic variants that are inherited in a recessive manner. A precise understanding of pathogenic recessive variants in a population would assist in pre-screening births of such patients. However, a systematic understanding of the contribution of recessive variants to Mendelian diseases is still lacking.MethodsGenetic diagnosis and variant discovery of 553 undiagnosed Korean patients with complex neurodevelopmental problems (KND for Korean NeuroDevelopmental cohort) were performed using whole exome sequencing of patients and their parents. Pathogenic variants were selected and evaluated based on a comparison to patient symptoms and genetic properties of the variants were analyzed.ResultsDisease-causing variants, including newly discovered variants, were identified in in 57.5% of the probands of the KND cohort. Of the 553 patients, 47.4% harbored variants that were previously reported as being pathogenic, and 35.1% of the previous reported pathogenic variants were inherited in a recessive manner. Genes that cause recessive disorders tend to be less constrained by loss-of-function variants and enriched in metabolic and mitochondrial pathways. This observation was applied to an estimation that approximately 1 in 17 healthy Korean individuals carry at least one of these pathogenic variants that develop severe neurodevelopmental problems in a recessive manner. Furthermore, the feasibility of these genes for carrier screening was evaluated.ConclusionsWe suggest that the odds are high for healthy individuals carrying a potentially pathogenic variant, and its genetic properties. Our results will serve as a foundation for recessive variant screening to reduce occurrences of rare Mendelian disease patients. Additionally, our results highlight the utility and necessity of whole exome sequencing-based diagnostics for improving patient care in a country with a centralized medical system.

Molecular defects identified by whole exome sequencing in a child with atypical mucopolysaccharidosis IIIB

2017 ◽  
Vol 30 (4) ◽  
Author(s):  
Qingwen Zeng ◽  
Yanjie Fan ◽  
Lili Wang ◽  
Zhuo Huang ◽  
Xuefan Gu ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Novel Mutation ◽  
Unknown Etiology ◽  
Mendelian Disease ◽  
Atypical Form ◽  
Pathogenic Variants ◽  
Diagnostic Potential ◽  
Whole Exome ◽  
Related Enzyme

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.

scholarly journals Biallelic DAB1 Variants Are Associated With Mild Lissencephaly and Cerebellar Hypoplasia

2021 ◽  
Vol 7 (2) ◽  
pp. e558
Author(s):  
Daphne J. Smits ◽  
Rachel Schot ◽  
Martina Wilke ◽  
Marjon van Slegtenhorst ◽  
Marie Claire Y. de Wit ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Splice Variants ◽  
Brain Mri ◽  
Cerebellar Vermis ◽  
Compound Heterozygous ◽  
Loss Of Function ◽  
Functional Studies ◽  
Pathogenic Variants ◽  
Whole Exome

ObjectiveWe aimed to identify pathogenic variants in a girl with epilepsy, developmental delay, cerebellar ataxia, oral motor difficulty, and structural brain abnormalities with the use of whole-exome sequencing.MethodsWhole-exome trio analysis and molecular functional studies were performed in addition to the clinical findings and neuroimaging studies.ResultsBrain MRI showed mild pachygyria, hypoplasia of the cerebellar vermis, and abnormal foliation of the cerebellar vermis, suspected for a variant in one of the genes of the Reelin pathway. Trio whole-exome sequencing and additional functional studies were performed to identify the pathogenic variants. Trio whole-exome sequencing revealed compound heterozygous splice variants in DAB1, both affecting the highly conserved functional phosphotyrosine-binding domain. Expression studies in patient-derived cells showed loss of normal transcripts, confirming pathogenicity.ConclusionsWe conclude that these variants are very likely causally related to the cerebral phenotype and propose to consider loss-of-function DAB1 variants in patients with RELN-like cortical malformations.

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 Likely Pathogenic Variants in One Third of Non-Syndromic Discontinuous Cleft Lip and Palate Patients

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 833 ◽  
Author(s):  
Bénédicte Demeer ◽  
Nicole Revencu ◽  
Raphael Helaers ◽  
Cica Gbaguidi ◽  
Stéphanie Dakpe ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Candidate Gene Approach ◽  
Loss Of Function ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Wide Range ◽  
Primary Palate

Oral clefts are composed of cleft of the lip, cleft of the lip and palate, or cleft of the palate, and they are associated with a wide range of expression and severity. When cleft of the palate is associated with cleft of the lip with preservation of the primary palate, it defines an atypical phenotype called discontinuous cleft. Although this phenotype may represent 5% of clefts of the lip and/or palate (CLP), it is rarely specifically referred to and its pathophysiology is unknown. We conducted whole exome sequencing (WES) and apply a candidate gene approach to non-syndromic discontinuous CLP individuals in order to identify genes and deleterious variants that could underlie this phenotype. We discovered loss-of-function variants in two out of the seven individuals, implicating FGFR1 and DLG1 genes, which represents almost one third of this cohort. Whole exome sequencing of clinically well-defined subgroups of CLP, such as discontinuous cleft, is a relevant approach to study CLP etiopathogenesis. It could facilitate more accurate clinical, epidemiological and fundamental research, ultimately resulting in better diagnosis and care of CLP patients. Non-syndromic discontinuous cleft lip and palate seems to have a strong genetic basis.

scholarly journals Molecular Diagnosis of Hereditary Neuropathies by Whole Exome Sequencing and Expanding the Phenotype Spectrum

2020 ◽  
Vol 23 (7) ◽  
pp. 426-433
Author(s):  
Sara Taghizadeh ◽  
Raheleh Vazehan ◽  
Maryam Beheshtian ◽  
Farnaz Sadeghinia ◽  
Zohreh Fattahi ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Genetic Diagnosis ◽  
Common Disease ◽  
Hereditary Neuropathies ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Established Disease ◽  
Peripheral Motor ◽  
Inherited Neuropathies

Background: Inherited peripheral neuropathies (IPNs) are a group of neuropathies affecting peripheral motor and sensory neurons. Charcot-Marie-Tooth (CMT) disease is the most common disease in this group. With recent advances in next-generation sequencing (NGS) technologies, more than 100 genes have been implicated for different types of CMT and other clinically and genetically inherited neuropathies. There are also a number of genes where neuropathy is a major feature of the disease such as spinocerebellar ataxia (SCA) and hereditary spastic paraplegia (HSP). We aimed to determine the genetic causes underlying IPNs in Iranian families. Methods: We performed whole exome sequencing (WES) for 58 PMP22 deletion-/duplication-negative unrelated Iranian patients with a spectrum of phenotypes and with a preliminary diagnosis of hereditary neuropathies. Results: Twenty-seven (46.6%) of the cases were genetically diagnosed with pathogenic or likely pathogenic variants. In this study, we identified genetically strong variants within genes not previously linked to any established disease phenotype in five (8.6%) patients. Conclusion: Our results highlight the advantage of using WES for genetic diagnosis in highly heterogeneous diseases such as IPNs. Moreover, functional analysis is required for novel and uncertain variants.

scholarly journals Whole-Exome Sequencing Uncovers Novel Causative Variants and Additional Findings in Three Patients Affected by Glycogen Storage Disease Type VI and Fanconi−Bickel Syndrome

2021 ◽  
Vol 11 ◽  
Author(s):  
Maryam Eghbali ◽  
Kiyana Sadat Fatemi ◽  
Shadab Salehpour ◽  
Maryam Abiri ◽  
Hassan Saei ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Glycogen Storage Disease Type ◽  
Glycogen Storage ◽  
Disease Genes ◽  
Carrier Status ◽  
Mendelian Disease ◽  
Pathogenic Variants ◽  
Glycogen Storage Diseases ◽  
Whole Exome

Glycogen storage diseases (GSDs) are the heterogeneous group of disorders caused by mutations in at least 30 different genes. Different types of GSDs, especially liver GSDs, take overlapping symptoms and can be clinically indistinguishable. This survey evaluated the use of whole-exome sequencing (WES) for the genetic analysis of the liver GSD-suspected patients in three unrelated families. An in-house filtering pipeline was used to assess rare pathogenic variants in GSD-associated genes, autosomal recessive/mendelian disorder genes (carrier status for genetic counseling subjects), and the ACMG’s list of 59 actionable genes. For the interpretation of the causative variants and the incidental/secondary findings, ACMG guidelines were applied. Additionally, we have explored PharmGKB class IA/IB pharmacogenetic variants. The segregation analysis was performed using Sanger sequencing for the novel causative variants. Bioinformatics analysis of the exome data in three individuals revealed three novel homozygous causative variants in the GSD-associated genes. The first variant, c.298_307delATGATCAACC in PYGL gene has related to HERS disease (GSD VI). Both variants of c.1043dupT and c.613-1G > C in SLC2A2 gene have been associated with Fanconi-Bickel syndrome (GSDXI). Eight pathogenic/likely pathogenic medical actionable findings in Mendelian disease genes and 10 pharmacogenetic variants with underlying drug response phenotypes have been identified. No known/expected pathogenic variants were detected in the ACMG’s list of 59 actionable genes. The logical filtering steps can help in finding other medical actionable secondary/incidental findings as well as effectively identifying the causative variants in heterogeneous conditions such as GSDs. Three novel variants related to GSD genes recognized in liver GSD-suspected patients with early infantile and childhood-age onset.

scholarly journals Genetic predisposition to hypouricemia on whole-exome sequencing analysis and its utilities in primary screening purposes

2018 ◽  
Author(s):  
Do Hyeon Cha ◽  
Heon Yung Gee ◽  
Raul Cachau ◽  
Jong Mun Choi ◽  
Daeui Park ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Genetic Predisposition ◽  
Clinical Care ◽  
Genetic Diagnosis ◽  
Kidney Injury ◽  
Sequencing Analysis ◽  
Primary Screening ◽  
Variant Discovery ◽  
Whole Exome

AbstractDifferentiating between inherited renal hypouricemia and transient hypouricemia is challenging. Here, we aimed to describe the genetic predisposition of hypouricemia patients using whole-exome sequencing (WES) and assess the feasibility for genetic diagnosis in primary screening. WES was performed for the discovery of diagnostic markers in discovery cohorts (N=31). Two known genetic markers SLC22A12 c.774G>A (p.Trp258*) and SLC22A12 c.269G>A (p.Arg90His) were identified, We genotyped for the 2 SLC22A12 SNPs among screened 50 hypouricemia subjects for the replication cohorts; 47 carried known SLC22A12 markers; three unexplained hypouricemic cases were analyzed by using WES. We used 46 healthy internal controls for the variant discovery. Four novel variants of SLC22A12, c.408C>A (p.Asn136Lys), c.674C>A (p.Thr225Lys), c.851G>A (p.Arg284Gln), and c.1285G>A (p.Glu429Lys), and one novel variant of SLC2A9, c. 376A>G (p.Met155Val), were identified. After filtering out known genes (SLC22A12 and SLC2A9), the p.Arg78His variant in ASB12 was overlapped in two unexplained conditions. This is the first attempt to investigate the effectiveness of integrating exome sequencing and genotype into the clinical care for hypouricemia and determine the value of genetic diagnostic screening for hypouricemia in the clinical setting. Screening of just two SNPs (p.Trp258* and p.Arg90His) identified 87.7% (71/81) of patients with hypouricemia. Early identification and intervention of hypouricemia is feasible using genetic screening to prevent acute kidney injury, especially for soldiers and athletics.

scholarly journals A Novel Pathogenic Variant of G6PC3 Gene Presenting As Cyclic Neutropenia in a Pediatric Patient

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4191-4191
Author(s):  
Christian M Bruni ◽  
Wendy de la Rua ◽  
Sara Y Sadre ◽  
Jennifer M Nestor ◽  
Rafat Ahmed
Keyword(s):  
Bone Marrow ◽  
Case Report ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Pathogenic Variant ◽  
Skin Infections ◽  
Cyclic Neutropenia ◽  
Pathogenic Variants ◽  
Whole Exome ◽  
Work Up

Abstract Background: Cyclic neutropenia is a rare hematologic disorder affecting neutrophils. It is classified by recurrent neutropenia (typically every three weeks) with associated symptoms including fever, malaise, and recurrent mucosal and skin infections. Pathogenic variants of ELANE, the gene that encodes neutrophil elastase, are thought to cause these findings, however, other pathogenic variants of different genes have also been noted. The estimated frequency of cyclic neutropenia is 1/10 6 in the general population. It is most commonly diagnosed in children but may rarely be diagnosed in adulthood. There is no known increased prevalence in women as compared to men. Whole Exome Sequencing can be used for diagnosis when genetic concerns are present. Objective: This case report aims to describe a novel pathogenic variant in a pediatric patient with cyclic neutropenia. Design/Method: Single subject case report Results: This is a single case report of a 7-year-old female with past medical history of cyclic neutropenia, anemia, recurrent skin and buccal infections, speech delay, and behavioral problems. The patient initially presented at age 1 with high fevers and skin infections and was found to have decreased neutrophil counts. Work up at that time was consistent with cyclic neutropenia. Bone marrow aspirate and biopsy performed at 1 and 7 years of age showed decreased neutrophil count with normal maturation without any evidence of MDS. Her peripheral blood for bone marrow failure evaluation was non-contributory. Due to persistent neutropenia, normal bone marrow findings, and being on weekly chronic G-CSF administration Whole Exome Sequencing was evaluated. Results of which showed a novel compound heterozygous pattern for two variant copies of the G6PC3 gene, with our patient inheriting a copy from each parent. Discussion: The G6PC3 gene encodes the expressed glucose-6-phosphate enzyme which catalyzes the final step in glycogenolysis. It is hypothesized that this deficiency causes unregulated levels of glucose, resulting in increased stress of the endoplasmic reticulum leading to apoptosis of neutrophils. Pathogenic variants of G6PC3 cause autosomal recessive G6PC3 deficiency and this can be clinically characterized as severe congenital neutropenia. Classic G6PC3 deficiency includes severe congenital neutropenia as well as cardiovascular abnormalities, urogenital abnormalities, and pulmonary hypertension. This novel pathogenic variant is likely responsible for the cyclic neutropenia observed in our patient. G6PC3 variants are an important differential diagnosis in the work-up of other causes of neutropenia. Whole Exome Sequencing is a cost-effective method for diagnosis and a valuable tool in evaluation and management of complex hematologic disorders. Disclosures No relevant conflicts of interest to declare.

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 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.

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