Rett-like Syndrome in a Pediatric Patient—A Challenging Diagnosis

2020 ◽  
Author(s):  
Sofia Simões Ferreira ◽  
Marta Mesquita ◽  
Joana Nunes ◽  
Isabel Alonso ◽  
Miguel Leão ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Pediatric Patient ◽  
Neurodevelopmental Disorders ◽  
De Novo ◽  
Hand Movements ◽  
Gene Variants ◽  
Neurodevelopmental Delay ◽  
Whole Exome ◽  
Rett’S Syndrome

AbstractNeurodevelopmental disorders with features overlapping Rett's syndrome frequently remain unexplained in patients without disease-causing variants in MECP2. Variants in IQSEC2 frequently cause nonsyndromic X-linked intellectual disability (XLID), although de novo variants may cause a severe syndrome that resembles Rett and Angelman's syndrome. We report a 7-year-old girl presenting severe neurodevelopmental delay, stereotypic hand movements, hypotonia, autistic-like features, inappropriate laughing/screaming spells, and symmetrical hypomyelination. A whole exome sequencing detected a novel de novo heterozygous truncating variant within the IQSEC2 gene. Variants of IQSEC2 should be considered in patients with Rett–Angelman phenotype spectrum and autistic features when those causes were excluded.

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.

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.

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 A Novel De Novo Frameshift Mutation in KAT6A Identified by Whole Exome Sequencing

2018 ◽  
Vol 08 (01) ◽  
pp. 010-014 ◽  
Author(s):  
Wafa Alazaizeh ◽  
Asem Alkhateeb
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Frameshift Mutation ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Brain Magnetic Resonance Imaging ◽  
Comparative Genomic ◽  
Feeding Difficulties ◽  
Whole Exome

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.

Coexistence of a Homozygous Chromosome 4q35.2 Deletion and Hidden IQSEC2 Pathogenic Variant in a Child with Intellectual Disability

2021 ◽  
pp. 1-7
Author(s):  
Tuğba Karaman Mercan ◽  
Ozden Altiok Clark ◽  
Ozgur Erkal ◽  
Banu Nur ◽  
Ercan Mihci ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Array Cgh ◽  
De Novo ◽  
Homozygous Deletion ◽  
Clinical Findings ◽  
Chromosome 4 ◽  
Heterozygous Deletion ◽  
Whole Exome

Terminal deletions in the long arm of chromosome 4 are an uncommon event, with a worldwide incidence of approximately 0.001%. The majority of these deletions occur de novo. Terminal deletion cases are usually accompanied by clinical findings that include facial and cardiac anomalies, as well as intellectual disability. In this study, we describe the case of a 2-year-old girl, the fourth child born to consanguineous parents. While her karyotype was normal, a homozygous deletion was identified in the chromosome 4q35.2 region by subtelomeric FISH. A heterozygous deletion of the chromosome 4q35.2 region was observed in both parents. According to the literature, this is the first report of a case that has inherited a homozygous deletion of chromosome 4qter from carrier parents. Subsequent array-CGH analyses were performed on both the case and her parents. Whole-exome sequencing was also carried out to determine potential variants. We detected a NM_001111125.3:c.2329G&#x3e;T (p.Glu777Ter) nonsense variant of the <i>IQSEC2</i> gene in the girl, a variant that is related to X-linked intellectual disability.

scholarly journals A Novel Frameshift Mutation in KAT6A Is Associated with Pancraniosynostosis

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.

scholarly journals Identification of de novo mutations for ARID1B haploinsufficiency associated with Coffin–Siris syndrome 1 in three Chinese families via array-CGH and whole exome sequencing

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Guanting Lu ◽  
Qiongling Peng ◽  
Lianying Wu ◽  
Jian Zhang ◽  
Liya Ma
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Array Cgh ◽  
De Novo ◽  
Current Knowledge ◽  
Comparative Genomic ◽  
De Novo Mutations ◽  
Single Nucleotide Variants ◽  
Whole Exome

Abstract Background Coffin–Siris syndrome (CSS) is a multiple malformation syndrome characterized by intellectual disability associated with coarse facial features, hirsutism, sparse scalp hair, and hypoplastic or absent fifth fingernails or toenails. CSS represents a small group of intellectual disability, and could be caused by at least twelve genes. The genetic background is quite heterogenous, making it difficult for clinicians and genetic consultors to pinpoint the exact disease types. Methods Array-Comparative Genomic Hybridization (array-CGH) and whole exome sequencing (WES) were applied for three trios affected with intellectual disability and clinical features similar with those of Coffin–Siris syndrome. Sanger sequencing was used to verify the detected single-nucleotide variants (SNVs). Results All of the three cases were female with normal karyotypes of 46, XX, born of healthy, non-consanguineous parents. A 6q25 microdeletion (arr[hg19]6q25.3(155,966,487–158,803,979) × 1) (2.84 Mb) (case 1) and two loss-of-function (LoF) mutations of ARID1B [c.2332 + 1G > A in case 2 and c.4741C > T (p.Q1581X) in case 3] were identified. All of the three pathogenic abnormalities were de novo, not inherited from their parents. After comparison of publicly available microdeletions containing ARID1B, four types of microdeletions leading to insufficient production of ARID1B were identified, namely deletions covering the whole region of ARID1B, deletions covering the promoter region, deletions covering the termination region or deletions covering enhancer regions. Conclusion Here we identified de novo ARID1B mutations in three Chinese trios. Four types of microdeletions covering ARID1B were identified. This study broadens current knowledge of ARID1B mutations for clinicians and genetic consultors.

scholarly journals Genetic Analysis of Children With Unexplained Developmental Delay and/or Intellectual Disability by Whole-Exome Sequencing

2021 ◽  
Vol 12 ◽  
Author(s):  
Jingjing Xiang ◽  
Yang Ding ◽  
Fei Yang ◽  
Ang Gao ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
Neurodevelopmental Disorders ◽  
Copy Number ◽  
Diagnostic Yield ◽  
Single Nucleotide ◽  
Whole Exome ◽  
Number Variation

Background: Whole-exome sequencing (WES) has been recommended as a first-tier clinical diagnostic test for individuals with neurodevelopmental disorders (NDDs). We aimed to identify the genetic causes of 17 children with developmental delay (DD) and/or intellectual disability (ID).Methods: WES and exome-based copy number variation (CNV) analysis were performed for 17 patients with unexplained DD/ID.Results: Single-nucleotide variant (SNV)/small insertion or deletion (Indel) analysis and exome-based CNV calling yielded an overall diagnostic rate of 58.8% (10/17), of which diagnostic SNVs/Indels accounted for 41.2% (7/17) and diagnostic CNVs accounted for 17.6% (3/17).Conclusion: Our findings expand the known mutation spectrum of genes related to DD/ID and indicate that exome-based CNV analysis could improve the diagnostic yield of patients with DD/ID.

scholarly journals Patients with KCNH1-related intellectual disability without distinctive features of Zimmermann-Laband/Temple-Baraitser syndrome

2021 ◽  
pp. jmedgenet-2020-107511
Author(s):  
Marion Aubert Mucca ◽  
Olivier Patat ◽  
Sandra Whalen ◽  
Lionel Arnaud ◽  
Giulia Barcia ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Cyclic Nucleotide ◽  
De Novo ◽  
Gingival Hyperplasia ◽  
Phenotype Correlation ◽  
Distinctive Features ◽  
Severe Intellectual Disability ◽  
Whole Exome ◽  
Epilepsy Gene

De novo missense variants in KCNH1 encoding Kv10.1 are responsible for two clinically recognisable phenotypes: Temple-Baraitser syndrome (TBS) and Zimmermann-Laband syndrome (ZLS). The clinical overlap between these two syndromes suggests that they belong to a spectrum of KCNH1-related encephalopathies. Affected patients have severe intellectual disability (ID) with or without epilepsy, hypertrichosis and distinctive features such as gingival hyperplasia and nail hypoplasia/aplasia (present in 20/23 reported cases).We report a series of seven patients with ID and de novo pathogenic KCNH1 variants identified by whole-exome sequencing or an epilepsy gene panel in whom the diagnosis of TBS/ZLS had not been first considered. Four of these variants, p.(Thr294Met), p.(Ala492Asp), p.(Thr493Asn) and p.(Gly496Arg), were located in the transmembrane domains S3 and S6 of Kv10.1 and one, p.(Arg693Gln), in its C-terminal cyclic nucleotide-binding homology domain (CNBHD). Clinical reappraisal by the referring clinical geneticists confirmed the absence of the distinctive gingival and nail features of TBS/ZLS.Our study expands the phenotypical spectrum of KCNH1-related encephalopathies to individuals with an attenuated extraneurological phenotype preventing a clinical diagnosis of TBS or ZLS. This subtype may be related to recurrent substitutions of the Gly496, suggesting a genotype–phenotype correlation and, possibly, to variants in the CNBHD domain.

scholarly journals New Candidates for Autism/Intellectual Disability Identified by Whole-Exome Sequencing

2021 ◽  
Vol 22 (24) ◽  
pp. 13439
Author(s):  
Lucia Pia Bruno ◽  
Gabriella Doddato ◽  
Floriana Valentino ◽  
Margherita Baldassarri ◽  
Rossella Tita ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Molecular Diagnosis ◽  
De Novo ◽  
Genetic Locus ◽  
Autism Spectrum ◽  
Bioinformatic Tools ◽  
Pathogenic Variants ◽  
Whole Exome

Intellectual disability (ID) is characterized by impairments in the cognitive processes and in the tasks of daily life. It encompasses a clinically and genetically heterogeneous group of neurodevelopmental disorders often associated with autism spectrum disorder (ASD). Social and communication abilities are strongly compromised in ASD. The prevalence of ID/ASD is 1–3%, and approximately 30% of the patients remain without a molecular diagnosis. Considering the extreme genetic locus heterogeneity, next-generation sequencing approaches have provided powerful tools for candidate gene identification. Molecular diagnosis is crucial to improve outcome, prevent complications, and hopefully start a therapeutic approach. Here, we performed parent–offspring trio whole-exome sequencing (WES) in a cohort of 60 mostly syndromic ID/ASD patients and we detected 8 pathogenic variants in genes already known to be associated with ID/ASD (SYNGAP1, SMAD6, PACS1, SHANK3, KMT2A, KCNQ2, ACTB, and POGZ). We found four de novo disruptive variants of four novel candidate ASD/ID genes: MBP, PCDHA1, PCDH15, PDPR. We additionally selected via bioinformatic tools many variants in unknown genes that alone or in combination can contribute to the phenotype. In conclusion, our data confirm the efficacy of WES in detecting pathogenic variants of known and novel ID/ASD genes.

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