A De Novo heterozygous frameshift mutation identified in
            BCL11B
            causes neurodevelopmental disorder by whole exome sequencing

AbstractIntellectual disability is a common condition with multiple etiologies. The number of monogenic causes has increased steadily in recent years due to the implementation of next generation sequencing. Here, we describe a 2-year-old boy with global developmental delay and intellectual disability. The child had feeding difficulties since birth. He had delayed motor skills and muscular hypotonia. Brain magnetic resonance imaging revealed diffuse white matter loss and thinning of the corpus callosum. Banded karyotype and comparative genomic hybridization (CGH) array were normal. Whole exome sequencing revealed a novel de novo frameshift mutation c.3390delA (p.Lys1130Asnfs*4) in KAT6A gene (NM_006766.4). The heterozygous mutation was confirmed by Sanger sequencing in the patient and its absence in his parents. KAT6A that encodes a histone acetyltransferase has been recently found to be associated with a neurodevelopmental disorder autosomal dominant mental retardation 32 (OMIM: no. 616268). Features of this disorder are nonspecific, which makes it difficult to characterize the condition based on the clinical symptoms alone. Therefore, our findings confirm the utility of whole exome sequencing to quickly and reliably identify the etiology of such conditions.

Download Full-text

Case Report: A Novel De Novo Missense Mutation of the GRIA2 Gene in a Chinese Case of Neurodevelopmental Disorder With Language Impairment

Frontiers in Genetics ◽

10.3389/fgene.2021.794766 ◽

2021 ◽

Vol 12 ◽

Author(s):

Bingbo Zhou ◽

Chuan Zhang ◽

Lei Zheng ◽

Zhiqiang Wang ◽

Xue Chen ◽

...

Keyword(s):

Exome Sequencing ◽

Missense Mutation ◽

Developmental Delay ◽

Whole Exome Sequencing ◽

Language Impairment ◽

De Novo ◽

Neurodevelopmental Disorder ◽

Behavioral Abnormalities ◽

Whole Exome ◽

Chinese Case

Introduction: Neurodevelopmental disorders with language impairment and behavioral abnormalities (NEDLIB) are a disease caused by heterozygous variants in the glutamate ionotropic receptor AMPA type subunit 2 (GRIA2) gene, which manifest as impaired mental development or developmental delay, behavioral abnormalities including autistic characteristics, and language disorders. Currently, only a few mutations in the GRIA2 gene have been discovered.Methods: A GRIA2 variation was detected in a patient by whole-exome sequencing, and the site was validated by Sanger sequencing from the family.Results: We report a Chinese case of NEDLIB in a girl with language impairment and developmental delay through whole-exome sequencing (WES). Genetic analysis showed that there was a de novo missense mutation, c.1934T > G (p.Leu645Arg), in the GRIA2 gene (NM_001083619.1), which has never been reported before.Conclusion: Our case shows the potential diagnostic role of WES in NEDLIB, expands the GRIA2 gene mutation spectrum, and further deepens the understanding of NEDLIB. Deepening the study of the genetic and clinical heterogeneity, treatment, and prognosis of the disease is still our future challenge and focus.

Download Full-text

Case report : a novel ASXL3 gene variant in a Sudanese boy

BMC Pediatrics ◽

10.1186/s12887-021-03038-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ke Wu ◽

Yan Cong

Keyword(s):

Intellectual Disability ◽

Exome Sequencing ◽

Whole Exome Sequencing ◽

De Novo ◽

Neurodevelopmental Disorder ◽

Psychomotor Development ◽

Gene Variant ◽

Feeding Difficulties ◽

Severe Intellectual Disability ◽

Whole Exome

Abstract Background Bainbridge-Ropers syndrome (BRPS) [OMIM#615485] is a neurodevelopmental disorder, characterized by delayed psychomotor development with generalized hypotonia, moderate to severe intellectual disability, poor or absent speech, feeding difficulties, growth failure, dysmorphic craniofacial features and minor skeletal features. The aim of this study was to investigate the genetic etiology of a Sudanese boy with severe developmental delay, intellectual disability, and craniofacial phenotype using trio-based whole-exome sequencing. To our knowledge, no patients with ASXL3 gene variant c.3043C>T have been reported detailedly in literature. Case presentation The patient (male, 3 years 6 months) was the first born of a healthy non-consanguineous couple originating from Sudan, treated for “psychomotor retardation” for more than 8 months in Yiwu. The patient exhibited severely delayed milestones in physiological and intellectual developmental stages, language impairment, poor eye-contact, lack of subtle motions of fingers, fear of claustrophobic space, hypotonia, clinodactyly, autistic features. Peripheral blood samples were collected from the patient and his parents. Trio-based whole-exome sequencing(Trio-WES) identified a de novo heterozygous ASXL3 gene variant c.3043C>T;p.Q1015X. Sanger sequencing verified variants of this family. Conclusion Trio-WES analysis identified a de novo nonsense variant (c.3043C>T) of ASXL3 gene in a Sudanese boy. To our knowledge, the patient with this variant has not been reported previously in literature. This study presents a new case for ASXL3 gene variants, which expanded the mutational and phenotypic spectrum.

Download Full-text

A Novel Frameshift Mutation in KAT6A Is Associated with Pancraniosynostosis

Journal of Pediatric Genetics ◽

10.1055/s-0040-1710330 ◽

2020 ◽

Author(s):

Fady P. Marji ◽

Jennifer A. Hall ◽

Erin Anstadt ◽

Suneeta Madan-Khetarpal ◽

Jesse A. Goldstein ◽

...

Keyword(s):

Intellectual Disability ◽

Exome Sequencing ◽

Whole Exome Sequencing ◽

Frameshift Mutation ◽

De Novo ◽

Cranial Sutures ◽

Speech Delay ◽

First Case ◽

Whole Exome ◽

Suture Fusion

AbstractDe novo heterozygous mutations in the KAT6A gene give rise to a distinct intellectual disability syndrome, with features including speech delay, cardiac anomalies, craniofacial dysmorphisms, and craniosynostosis. Here, we reported a 16-year-old girl with a novel pathogenic variant of the KAT6A gene. She is the first case to possess pancraniosynostosis, a rare suture fusion pattern, affecting all her major cranial sutures. The diagnosis of KAT6A syndrome is established via recognition of its inherent phenotypic features and the utilization of whole exome sequencing. Thorough craniofacial evaluation is imperative, craniosynostosis may require operative intervention, the delay of which may be detrimental.

Download Full-text

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

10.21203/rs.3.rs-60924/v1 ◽

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.

Download Full-text

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

10.21203/rs.3.rs-60924/v2 ◽

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.

Download Full-text

Towards a Change in the Diagnostic Algorithm of Autism Spectrum Disorders: Evidence Supporting Whole Exome Sequencing as a First-Tier Test

Genes ◽

10.3390/genes12040560 ◽

2021 ◽

Vol 12 (4) ◽

pp. 560

Author(s):

Ana Arteche-López ◽

Maria José Gómez Rodríguez ◽

Maria Teresa Sánchez Calvin ◽

Juan Francisco Quesada-Espinosa ◽

Jose Miguel Lezana Rosales ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

De Novo ◽

Neurodevelopmental Disorder ◽

Genetic Diagnosis ◽

Diagnostic Algorithm ◽

Autism Spectrum ◽

Chromosomal Microarray ◽

De Novo Mutations ◽

Whole Exome

Autism spectrum disorder (ASD) is a prevalent and extremely heterogeneous neurodevelopmental disorder (NDD) with a strong genetic component. In recent years, the clinical relevance of de novo mutations to the aetiology of ASD has been demonstrated. Current guidelines recommend chromosomal microarray (CMA) and a FMR1 testing as first-tier tests, but there is increasing evidence that support the use of NGS for the diagnosis of NDDs. Specifically in ASD, it has not been extensively evaluated and, thus, we performed and compared the clinical utility of CMA, FMR1 testing, and/or whole exome sequencing (WES) in a cohort of 343 ASD patients. We achieved a global diagnostic rate of 12.8% (44/343), the majority of them being characterised by WES (33/44; 75%) compared to CMA (9/44; 20.4%) or FMR1 testing (2/44; 4.5%). Taking into account the age at which genetic testing was carried out, we identified a causal genetic alteration in 22.5% (37/164) of patients over 5 years old, but only in 3.9% (7/179) of patients under this age. Our data evidence the higher diagnostic power of WES compared to CMA in the study of ASD and support the implementation of WES as a first-tier test for the genetic diagnosis of this disorder, when there is no suspicion of fragile X syndrome.

Download Full-text

Spectrum of movement disorders in GNAO1 encephalopathy: in-depth phenotyping and case-by-case analysis

Orphanet Journal of Rare Diseases ◽

10.1186/s13023-020-01594-3 ◽

2020 ◽

Vol 15 (1) ◽

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.

Download Full-text

Whole exome sequencing reveals de novo pathogenic variants inKAT6Aas a cause of a neurodevelopmental disorder

American Journal of Medical Genetics Part A ◽

10.1002/ajmg.a.37670 ◽

2016 ◽

Vol 170 (7) ◽

pp. 1791-1798 ◽

Cited By ~ 22

Author(s):

Francisca Millan ◽

Megan T. Cho ◽

Kyle Retterer ◽

Kristin G. Monaghan ◽

Renkui Bai ◽

...

Keyword(s):

Exome Sequencing ◽

Whole Exome Sequencing ◽

De Novo ◽

Neurodevelopmental Disorder ◽

Pathogenic Variants ◽

Whole Exome

Download Full-text

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

Pediatric Research ◽

10.1038/s41390-021-01509-3 ◽

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.

Download Full-text