scholarly journals Case Report: Christianson Syndrome Caused by SLC9A6 Mutation: From Case to Genotype-Phenotype Analysis

2021 ◽  
Vol 12 ◽  
Author(s):  
Yueyun Lan ◽  
Sheng Yi ◽  
Mengting Li ◽  
Jinqiu Wang ◽  
Qi Yang ◽  
...  
Keyword(s):  
Developmental Delay ◽  
De Novo ◽  
Autism Spectrum ◽  
Frontal Pole ◽  
Motor Delay ◽  
Distal Muscle ◽  
Whole Exome ◽  
Phenotype Analysis ◽  
Genetics And Genomics ◽  
Core Symptoms

Christianson syndrome (CS) is an X-linked neurodevelopmental syndrome characterized by microcephaly, epilepsy, ataxia, and severe generalized developmental delay. Pathogenic mutations in the SLC9A6 gene, which encodes the Na+/H+ exchanger protein member 6 (NHE6), are associated with CS and autism spectrum disorder in males. In this study, whole exome sequencing (WES) and Sanger sequencing revealed a novel de novo frameshift variant c.1548_1549insT of SLC9A6 in a 14-month-old boy with early-onset seizures. According to The American College of Medical Genetics and Genomics (ACMG)/the Association for Molecular Pathology (AMP) guidelines, the variant was classified as pathogenic. The proband presented with several core symptoms of typical epilepsy, including microcephaly, motor delay, distal muscle weakness, micrognathia, occasional unprovoked laughter, swallowing and speech difficulties. Electroencephalography (EEG) showed spikes-slow waves in frontal pole, frontal, anterior temporal and frontal midline point areas. Gesell development schedules (GDS) indicated generalized developmental delay. We also summarized all the reported variants and analyzed the correlation of genotype and phenotype of CS. Our study extends the mutation spectrum of the SLC9A6 gene, and it might imply that the phenotypes of CS are not correlated with SLC9A6 genotypes.

scholarly journals Case Report: De novo Variants of KMT2E Cause O'Donnell-Luria-Rodan Syndrome: Additional Cases and Literature Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Yang Li ◽  
Lijuan Fan ◽  
Rong Luo ◽  
Zuozhen Yang ◽  
Meng Yuan ◽  
...  
Keyword(s):  
Developmental Delay ◽  
De Novo ◽  
Clinical Manifestations ◽  
Global Developmental Delay ◽  
Feeding Difficulties ◽  
Gene Testing ◽  
Whole Exome ◽  
Systemic Disorder ◽  
Synonymous Variant ◽  
Genetics And Genomics

Introduction: O'Donnell-Luria-Rodan syndrome was recently identified as an autosomal dominant systemic disorder caused by variants in KMT2E. It is characterized by global developmental delay, some patients also exhibit autism, seizures, hypotonia, and/or feeding difficulties.Methods: Whole-exome sequencing of family trios were performed for two independent children with unexplained recurrent seizures and developmental delay. Both cases were identified as having de novo variants in KMT2E. We also collected and summarized the clinical data and diagnosed them with O'Donnell-Luria-Rodan syndrome. Structural-prediction programs were used to draw the variants' locations.Results: A 186 G>A synonymous variant [NM_182931.3:exon4: c.186G>A (p.Ala62=)] was found in one family, resulting in alternative splicing acid. A 5417 C>T transition variant [NM_182931.3:exon27: c.5417C>T (p.Pro1806Leu)] was found in another family, resulting in 1806 Pro-to-Leu substitution. Both variants were classified as likely pathogenic according to the ACMG (American College of Medical Genetics and Genomics) guidelines and verified by Sanger sequencing.Conclusion: To date, three studies of O'Donnell-Luria-Rodan syndrome have been reported with heterogeneous clinical manifestations. As a newly recognized inherited systemic disorder, O'Donnell-Luria-Rodan syndrome needs to be paid more attention, especially in gene testing.

IL1RAPL1 Gene Deletion in a Female Patient with Developmental Delay and Continuous Spike-Wave during Sleep

2021 ◽  
Author(s):  
Evan Jiang ◽  
Mark P. Fitzgerald ◽  
Katherine L. Helbig ◽  
Ethan M. Goldberg
Keyword(s):  
Intellectual Disability ◽  
Developmental Delay ◽  
Synapse Formation ◽  
De Novo ◽  
Interleukin 1 ◽  
Autism Spectrum ◽  
Neurological Dysfunction ◽  
Behavioral Disorder ◽  
Clinical Genetic ◽  
Severe Intellectual Disability

AbstractInterleukin-1 receptor accessory protein-like 1 (IL1RAPL1) encodes a protein that is highly expressed in neurons and has been shown to regulate neurite outgrowth as well as synapse formation and synaptic transmission. Clinically, mutations in or deletions of IL1RAPL1 have been associated with a spectrum of neurological dysfunction including autism spectrum disorder and nonsyndromic X-linked developmental delay/intellectual disability of varying severity. Nearly all reported cases are in males; in the few reported cases involving females, the clinical presentation was mild or the deletion was identified in phenotypically normal carriers in accordance with X-linked inheritance. Using genome-wide microarray analysis, we identified a novel de novo 373 kb interstitial deletion of the X chromosome (Xp21.1-p21.2) that includes exons 4 to 6 of the IL1RAPL1 gene in an 8-year-old girl with severe intellectual disability and behavioral disorder with a history of developmental regression. Overnight continuous video electroencephalography revealed electrical status epilepticus in sleep (ESES). This case expands the clinical genetic spectrum of IL1RAPL1-related neurodevelopmental disorders and highlights a new genetic association of ESES.

scholarly journals SENP1 in the retrosplenial agranular cortex regulates core autistic-like symptoms in mice

2021 ◽  
Author(s):  
Kan Yang ◽  
Yuhan Shi ◽  
Xiujuan Du ◽  
Yuefang Zhang ◽  
Shifang Shan ◽  
...  
Keyword(s):  
Social Interaction ◽  
De Novo ◽  
Fragile X ◽  
Neurodevelopmental Disorder ◽  
Autism Spectrum ◽  
Repetitive Behaviors ◽  
Genetic Components ◽  
Truncating Mutation ◽  
Synaptic Functions ◽  
Core Symptoms

AbstractAutism spectrum disorder (ASD) is a highly heritable complex neurodevelopmental disorder. While the core symptoms of ASD are defects of social interaction and repetitive behaviors, over 50% of ASD patients have comorbidity of intellectual disabilities (ID) or developmental delay (DD), raising the question whether there are genetic components and neural circuits specific for core symptoms of ASD. Here, by focusing on ASD patients who do not show compound ID or DD, we identified a de novo heterozygous gene-truncating mutation of the Sentrin-specific peptidase1 (SENP1) gene, coding the small ubiquitin-like modifiers (SUMO) deconjugating enzyme, as a potentially new candidate gene for ASD. We found that Senp1 haploinsufficient mice exhibited core symptoms of autism such as deficits in social interaction and repetitive behaviors, but normal learning and memory ability. Moreover, we found that the inhibitory and excitatory synaptic functions were severely affected in the retrosplenial agranular (RSA) cortex of Senp1 haploinsufficient mice. Lack of Senp1 led to over SUMOylation and degradation of fragile X mental retardation protein (FMRP) proteins, which is coded by the FMR1 gene, also implicated in syndromic autism. Importantly, re-introducing SENP1 or FMRP specifically in RSA fully rescued the defects of synaptic functions and core autistic-like symptoms of Senp1 haploinsufficient mice. Taken together, these results elucidate that disruption of the SENP1-FMRP regulatory axis in the RSA may cause core autistic symptoms, which further provide a candidate brain region for therapeutic intervene of ASD by neural modulation approaches.

scholarly journals Identification of a β-Arrestin 2 Mutation Related to Autism by Whole-Exome Sequencing

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yunfei Tang ◽  
Yamei Liu ◽  
Lei Tong ◽  
Shini Feng ◽  
Dongshu Du ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Developmental Stages ◽  
De Novo ◽  
Repetitive Behavior ◽  
Brain Regions ◽  
Autism Spectrum ◽  
Potential Contribution ◽  
De Novo Mutations ◽  
Whole Exome

Autism spectrum disorder (ASD) is a complex neurological disease characterized by impaired social communication and interaction skills, rigid behavior, decreased interest, and repetitive activities. The disease has a high degree of genetic heterogeneity, and the genetic cause of ASD in many autistic individuals is currently unclear. In this study, we report a patient with ASD whose clinical features included social interaction disorder, communication disorder, and repetitive behavior. We examined the patient’s genetic variation using whole-exome sequencing technology and found new de novo mutations. After analysis and evaluation, ARRB2 was identified as a candidate gene. To study the potential contribution of the ARRB2 gene to the human brain development and function, we first evaluated the expression profile of this gene in different brain regions and developmental stages. Then, we used weighted gene coexpression network analysis to analyze the associations between ARRB2 and ASD risk genes. Additionally, the spatial conformation and stability of the ARRB2 wild type and mutant proteins were examined by simulations. Then, we further established a mouse model of ASD. The results showed abnormal ARRB2 expression in the mouse ASD model. Our study showed that ARRB2 may be a risk gene for ASD, but the contribution of de novo ARRB2 mutations to ASD is unclear. This information will provide references for the etiology of ASD and aid in the mechanism-based drug development and treatment.

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

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.

scholarly journals A de novo TOP2B variant associated with global developmental delay and autism spectrum disorder

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Takuya Hiraide ◽  
Seiji Watanabe ◽  
Tomoko Matsubayashi ◽  
Kumiko Yanagi ◽  
Mitsuko Nakashima ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Developmental Delay ◽  
De Novo ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Global Developmental Delay

A method to delineate de novo missense variants across pathways prioritizes genes linked to autism

2021 ◽  
Vol 13 (594) ◽  
pp. eabc1739
Author(s):  
Amanda Koire ◽  
Panagiotis Katsonis ◽  
Young Won Kim ◽  
Christie Buchovecky ◽  
Stephen J. Wilson ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Protein Function ◽  
De Novo ◽  
Autism Spectrum ◽  
Homologous Gene ◽  
Fitness Effect ◽  
Missense Variants ◽  
Whole Exome ◽  
New Gene ◽  
The Impact

Genotype-phenotype relationships shape health and population fitness but remain difficult to predict and interpret. Here, we apply an evolutionary action method to de novo missense variants in whole-exome sequences of individuals with autism spectrum disorder (ASD) to unravel genes and pathways connected to ASD. Evolutionary action predicts the impact of missense variants on protein function by measuring the fitness effect based on phylogenetic distances and substitution odds in homologous gene sequences. By examining de novo missense variants in 2384 individuals with ASD (probands) compared to matched siblings without ASD, we found missense variants in 398 genes representing 23 pathways that were biased toward higher evolutionary action scores than expected by random chance; these pathways were involved in axonogenesis, synaptic transmission, and neurodevelopment. The predicted fitness impact of de novo and inherited missense variants in candidate genes correlated with the IQ of individuals with ASD, even for new gene candidates. Taking an evolutionary action method, we detected those missense variants most likely to contribute to ASD pathogenesis and elucidated their phenotypic impact. This approach could be applied to integrate missense variants across a patient cohort to identify genes contributing to a shared phenotype in other complex diseases.

Neurodevelopmental phenotypes associated with pathogenic variants in SLC6A1

2021 ◽  
pp. jmedgenet-2021-107694
Author(s):  
Ashley Kahen ◽  
Haluk Kavus ◽  
Alexa Geltzeiler ◽  
Catherine Kentros ◽  
Cora Taylor ◽  
...  
Keyword(s):  
Developmental Delay ◽  
De Novo ◽  
Language Disorder ◽  
Synaptic Cleft ◽  
Binding Pocket ◽  
Autism Spectrum ◽  
Gamma Aminobutyric Acid ◽  
Vineland Adaptive Behavior Scales ◽  
Care Givers ◽  
Pathogenic Variants

BackgroundSLC6A1 encodes GAT-1, a major gamma-aminobutyric acid (GABA) transporter in the brain. GAT-1 maintains neurotransmitter homeostasis by removing excess GABA from the synaptic cleft. Pathogenic variants in SLC6A1 disrupt the reuptake of GABA and are associated with a neurobehavioural phenotype.MethodsMedical history interviews, seizure surveys, Vineland Adaptive Behavior Scales Second Edition and other behavioural surveys were completed by primary care givers of 28 participants in Simons Searchlight. All participants underwent clinical whole exome sequencing or gene panel sequencing. Additional cases from the medical literature with comparable data were included.ResultsWe identified 28 individuals with largely de novo pathogenic/likely pathogenic variants including missense (15/21 or 71%) and truncating variants (6/21 or 29%). Missense variants were largely clustered around the sixth and seventh transmembrane domains, which functions as a GABA binding pocket. The phenotype of individuals with pathogenic variants in SLC6A1 includes hypotonia, intellectual disability/developmental delay, language disorder/speech delay, autism spectrum disorder, sleep issues and seizures.ConclusionPathogenic variants in SLC6A1 are associated with a clinical phenotype of developmental delay, behaviour problems and seizures. Understanding of the genotype–phenotype correlation within SLC6A1 may provide opportunities to develop new treatments for GABA-related conditions.

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