scholarly journals Missense and truncating variants in CHD5 in a dominant neurodevelopmental disorder with intellectual disability, behavioral disturbances, and epilepsy

2021 ◽  
Author(s):  
Ilaria Parenti ◽  
◽  
Daphné Lehalle ◽  
Caroline Nava ◽  
Erin Torti ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Behavioral Problems ◽  
Neuronal Development ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Speech Delay ◽  
Nurd Complex ◽  
Behavioral Disturbances ◽  
Nucleosome Remodeling ◽  
Motor Delay

AbstractLocated in the critical 1p36 microdeletion region, the chromodomain helicase DNA-binding protein 5 (CHD5) gene encodes a subunit of the nucleosome remodeling and deacetylation (NuRD) complex required for neuronal development. Pathogenic variants in six of nine chromodomain (CHD) genes cause autosomal dominant neurodevelopmental disorders, while CHD5-related disorders are still unknown. Thanks to GeneMatcher and international collaborations, we assembled a cohort of 16 unrelated individuals harboring heterozygous CHD5 variants, all identified by exome sequencing. Twelve patients had de novo CHD5 variants, including ten missense and two splice site variants. Three familial cases had nonsense or missense variants segregating with speech delay, learning disabilities, and/or craniosynostosis. One patient carried a frameshift variant of unknown inheritance due to unavailability of the father. The most common clinical features included language deficits (81%), behavioral symptoms (69%), intellectual disability (64%), epilepsy (62%), and motor delay (56%). Epilepsy types were variable, with West syndrome observed in three patients, generalized tonic–clonic seizures in two, and other subtypes observed in one individual each. Our findings suggest that, in line with other CHD-related disorders, heterozygous CHD5 variants are associated with a variable neurodevelopmental syndrome that includes intellectual disability with speech delay, epilepsy, and behavioral problems as main features.

scholarly journals MED13L-related intellectual disability due to paternal germinal mosaicism

2021 ◽  
pp. mcs.a006124
Author(s):  
Beata Bessenyei ◽  
Istvan Balogh ◽  
Attila Mokanszki ◽  
Aniko Ujfalusi ◽  
Rolph Pfundt ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
De Novo ◽  
Mediator Complex ◽  
Facial Dysmorphism ◽  
Facial Features ◽  
Speech Delay ◽  
Motor Delay ◽  
First Case ◽  
Intragenic Deletion ◽  
Germinal Mosaicism

The MED13L-related intellectual disability or MRFACD syndrome (Mental retardation and distinctive facial features with or without cardiac defects; MIM # 616789) is one of the most common form of syndromic intellectual disability with about a hundred cases reported so far. Affected individuals share overlapping features comprising intellectual disability, hypotonia, motor delay, remarkable speech delay, and a recognizable facial gestalt. De novo disruption of the MED13L gene by deletions, duplications or sequence variants has been identified deleterious. Siblings affected by intragenic deletion transmitted from a mosaic parent have been reported once in the literature. We now present the first case of paternal germinal mosaicism for a missense MED13L variant causing MRFACD syndrome in one of the father's children and be the likely cause of intellectual disability and facial dysmorphism in the other. As part of the Mediator complex, the MED proteins have an essential role in regulating transcription. 32 subunits of the Mediator complex genes have been linked to congenital malformations that are now acknowledged as transcriptomopathies. The MRFACD syndrome has been suggested to represent a recognizable phenotype.

scholarly journals Okur-Chung Neurodevelopmental Syndrome-linked CK2α mutations have reduced kinase activity

2021 ◽  
Author(s):  
Isabel Dominguez ◽  
Jose Cruz Gamero ◽  
Victor Corasolla ◽  
Nicolas Dacher ◽  
Sampath Rangasamy ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Social Interaction ◽  
Protein Kinase ◽  
Behavioral Problems ◽  
Mammalian Cells ◽  
Kinase Activity ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Biological Studies ◽  
Repetitive Movements

Abstract The Okur-Chung Neurodevelopmental Syndrome, or OCNDS, is a newly discovered rare neurodevelopmental disorder. It is characterized by developmental delay, intellectual disability, behavioral problems (hyperactivity, repetitive movements and social interaction deficits), hypotonia, epilepsy and language/verbalization deficits. OCNDS is linked to de novo variants in CSNK2A1, that lead to missense or deletion/truncating mutations in the encoded protein, the protein kinase CK2a. Eighteen different missense CK2a mutants have been identified to date, however no biochemical or cell biological studies have yet been performed to clarify the functional impact of such mutations. Here, we show that 15 different missense CK2a mutations lead to varying degrees of loss of kinase activity as recombinant purified proteins and when mutants are ectopically expressed in mammalian cells. We further detect changes in the phosphoproteome of three patient derived fibroblast lines and show that the subcellular localization of CK2a is altered for some of the OCNDS-linked mutants and in patient derived fibroblasts. Our data argue that reduced kinase activity and abnormal localization of CK2a may underlie the OCNDS phenotype.

scholarly journals A Novel WAC Loss of Function Mutation in an Individual Presenting with Encephalopathy Related to Status Epilepticus during Sleep (ESES)

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 344 ◽  
Author(s):  
Emanuela Leonardi ◽  
Mariagrazia Bellini ◽  
Maria C. Aspromonte ◽  
Roberta Polli ◽  
Anna Mercante ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Status Epilepticus ◽  
Behavioral Problems ◽  
Rare Variants ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Somatic Mosaicism ◽  
Coiled Coil ◽  
Loss Of Function ◽  
De Novo Mutations

WAC (WW Domain Containing Adaptor With Coiled-Coil) mutations have been reported in only 20 individuals presenting a neurodevelopmental disorder characterized by intellectual disability, neonatal hypotonia, behavioral problems, and mildly dysmorphic features. Using targeted deep sequencing, we screened a cohort of 630 individuals with variable degrees of intellectual disability and identified five WAC rare variants: two variants were inherited from healthy parents; two previously reported de novo mutations, c.1661_1664del (p.Ser554*) and c.374C>A (p.Ser125*); and a novel c.381+2T>C variant causing the skipping of exon 4 of the gene, inherited from a reportedly asymptomatic father with somatic mosaicism. A phenotypic evaluation of this individual evidenced areas of cognitive and behavioral deficits. The patient carrying the novel splicing mutation had a clinical history of encephalopathy related to status epilepticus during slow sleep (ESES), recently reported in another WAC individual. This first report of a WAC somatic mosaic remarks the contribution of mosaicism in the etiology of neurodevelopmental and neuropsychiatric disorders. We summarized the clinical data of reported individuals with WAC pathogenic mutations, which together with our findings, allowed for the expansion of the phenotypic spectrum of WAC-related disorders.

scholarly journals De novo coding variants in the AGO1 gene cause a neurodevelopmental disorder with intellectual disability

2020 ◽  
Author(s):  
Audrey Schalk ◽  
Margot A. Cousin ◽  
Thomas D. Challman ◽  
Karen E. Wain ◽  
Zöe Powis ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Amino Acid ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Three Dimensional ◽  
Amino Acid Residues ◽  
Protein Coding ◽  
Motor Delay ◽  
Pathogenic Variants ◽  
Coding Variants

ABSTRACTHigh-impact pathogenic variants in more than 1,000 protein-coding genes cause Mendelian forms of neurodevelopmental disorders (NDD), including the newly reported AGO2 gene. This study describes the molecular and clinical characterization of 28 probands with NDD harboring heterozygous AGO1 coding variants. De novo status was always confirmed when parents were available (26/28). A total of 15 unique variants leading to amino acid changes or deletions were identified: 12 missense variants, two in-frame deletions of one codon, and one canonical splice variant leading to a deletion of two amino acid residues. Some variants were recurrently identified in several unrelated individuals: p.(Phe180del), p.(Leu190Pro), p.(Leu190Arg), p.(Gly199Ser), p.(Val254Ile) and p.(Glu376del). AGO1 encodes the Argonaute 1 protein, which functions in gene-silencing pathways mediated by small non-coding RNAs. Three-dimensional protein structure predictions suggest that these variants might alter the flexibility of the AGO1 linkers domains, which likely would impair its function in mRNA processing. Affected individuals present with intellectual disability of varying severity, as well as speech and motor delay, autistic behavior and additional behavioral manifestations. Our study establishes that de novo coding variants in AGO1 are involved in a novel monogenic form of NDD, highly similar to AGO2 phenotype.

scholarly journals De novo coding variants in the AGO1 gene cause a neurodevelopmental disorder with intellectual disability

2021 ◽  
pp. jmedgenet-2021-107751
Author(s):  
Audrey Schalk ◽  
Margot A Cousin ◽  
Nikita R Dsouza ◽  
Thomas D Challman ◽  
Karen E Wain ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Amino Acid ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Three Dimensional ◽  
Amino Acid Residues ◽  
Motor Delay ◽  
Pathogenic Variants ◽  
Silencing Pathways ◽  
Coding Variants

BackgroundHigh-impact pathogenic variants in more than a thousand genes are involved in Mendelian forms of neurodevelopmental disorders (NDD).MethodsThis study describes the molecular and clinical characterisation of 28 probands with NDD harbouring heterozygous AGO1 coding variants, occurring de novo for all those whose transmission could have been verified (26/28).ResultsA total of 15 unique variants leading to amino acid changes or deletions were identified: 12 missense variants, two in-frame deletions of one codon, and one canonical splice variant leading to a deletion of two amino acid residues. Recurrently identified variants were present in several unrelated individuals: p.(Phe180del), p.(Leu190Pro), p.(Leu190Arg), p.(Gly199Ser), p.(Val254Ile) and p.(Glu376del). AGO1 encodes the Argonaute 1 protein, which functions in gene-silencing pathways mediated by small non-coding RNAs. Three-dimensional protein structure predictions suggest that these variants might alter the flexibility of the AGO1 linker domains, which likely would impair its function in mRNA processing. Affected individuals present with intellectual disability of varying severity, as well as speech and motor delay, autistic behaviour and additional behavioural manifestations.ConclusionOur study establishes that de novo coding variants in AGO1 are involved in a novel monogenic form of NDD, highly similar to the recently reported AGO2-related NDD.

Recurrent de novo missense variants in GNB2 can cause syndromic intellectual disability

2021 ◽  
pp. jmedgenet-2020-107462
Author(s):  
Natalie B Tan ◽  
Alistair T Pagnamenta ◽  
Matteo P Ferla ◽  
Jonathan Gadian ◽  
Brian HY Chung ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
G Proteins ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Missense Variant ◽  
Cellular Functions ◽  
Missense Variants ◽  
Neurodevelopmental Disease ◽  
Genes Encoding ◽  
International Data

PurposeBinding proteins (G-proteins) mediate signalling pathways involved in diverse cellular functions and comprise Gα and Gβγ units. Human diseases have been reported for all five Gβ proteins. A de novo missense variant in GNB2 was recently reported in one individual with developmental delay/intellectual disability (DD/ID) and dysmorphism. We aim to confirm GNB2 as a neurodevelopmental disease gene, and elucidate the GNB2-associated neurodevelopmental phenotype in a patient cohort.MethodsWe discovered a GNB2 variant in the index case via exome sequencing and sought individuals with GNB2 variants via international data-sharing initiatives. In silico modelling of the variants was assessed, along with multiple lines of evidence in keeping with American College of Medical Genetics and Genomics guidelines for interpretation of sequence variants.ResultsWe identified 12 unrelated individuals with five de novo missense variants in GNB2, four of which are recurrent: p.(Ala73Thr), p.(Gly77Arg), p.(Lys89Glu) and p.(Lys89Thr). All individuals have DD/ID with variable dysmorphism and extraneurologic features. The variants are located at the universally conserved shared interface with the Gα subunit, which modelling suggests weaken this interaction.ConclusionMissense variants in GNB2 cause a congenital neurodevelopmental disorder with variable syndromic features, broadening the spectrum of multisystem phenotypes associated with variants in genes encoding G-proteins.

scholarly journals A Private 16q24.2q24.3 Microduplication in a Boy with Intellectual Disability, Speech Delay and Mild Dysmorphic Features

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 707 ◽  
Author(s):  
Orazio Palumbo ◽  
Pietro Palumbo ◽  
Ester Di Muro ◽  
Luigia Cinque ◽  
Antonio Petracca ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
De Novo ◽  
Chromosome Region ◽  
Snp Array ◽  
Supporting Evidence ◽  
Speech Delay ◽  
Dysmorphic Features ◽  
Phenotype Comparison ◽  
Molecular Comparison ◽  
Snp Array Analysis

No data on interstitial microduplications of the 16q24.2q24.3 chromosome region are available in the medical literature and remain extraordinarily rare in public databases. Here, we describe a boy with a de novo 16q24.2q24.3 microduplication at the Single Nucleotide Polymorphism (SNP)-array analysis spanning ~2.2 Mb and encompassing 38 genes. The patient showed mild-to-moderate intellectual disability, speech delay and mild dysmorphic features. In DECIPHER, we found six individuals carrying a “pure” overlapping microduplication. Although available data are very limited, genomic and phenotype comparison of our and previously annotated patients suggested a potential clinical relevance for 16q24.2q24.3 microduplication with a variable and not (yet) recognizable phenotype predominantly affecting cognition. Comparing the cytogenomic data of available individuals allowed us to delineate the smallest region of overlap involving 14 genes. Accordingly, we propose ANKRD11, CDH15, and CTU2 as candidate genes for explaining the related neurodevelopmental manifestations shared by these patients. To the best of our knowledge, this is the first time that a clinical and molecular comparison among patients with overlapping 16q24.2q24.3 microduplication has been done. This study broadens our knowledge of the phenotypic consequences of 16q24.2q24.3 microduplication, providing supporting evidence of an emerging syndrome.

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

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.

Quando il disturbo del neurosviluppo ha un substrato genetico: un caso di sindrome di Kleefstra

2021 ◽  
Vol 24 (4) ◽  
pp. 114-117
Author(s):  
Lorena Sorasio ◽  
Luisa Franceschi ◽  
Lisa Pavinato ◽  
Antonella Peduto
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Point Mutation ◽  
Neurodevelopmental Disorders ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Diagnostic Classification ◽  
Molecular Cytogenetic ◽  
Sequencing Technologies ◽  
Molecular Cytogenetic Techniques

Neurodevelopmental disorders (ND) have an important prevalence in children; intellectual disability in particular occurs in a heterogeneous group of genetic conditions. The evolution of molecular cytogenetic techniques and the recent advances in exome sequencing technologies have enormously implemented the possibilities of diagnostic classification in children with cognitive disabilities due to genetics. The paper presents the case of a patient with a neurodevelopmental disorder who was diagnosed with Kleefstra (KS) syndrome, caused by a point mutation de novo of EHMT1 gene.

scholarly journals De novo and bi-allelic variants in AP1G1 cause neurodevelopmental disorder with developmental delay, intellectual disability, and epilepsy

2021 ◽  
Author(s):  
Muhammad A. Usmani ◽  
Zubair M. Ahmed ◽  
Magini Pamela ◽  
Victor Murcia Pienkowski ◽  
Kristen J. Rasmussen ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Developmental Delay ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Allelic Variants
Sign in / Sign up

Export Citation Format

Share Document