Humans ; Drug Resistant Epilepsy ; Neurodevelopmental Disorders/genetics*

Autism spectrum disorder (ASD) is a set of neurodevelopmental disorders. Patients usually exhibit certain degree of social interaction impairment in accompany with impairment in language development as well as repetitive behaviors or interests. In recent years, ASD-related variants, genes, functional pathways, and expression patterns in the brain have been discovered, along with advance in sequencing techniques. This article reviews various aspects of genetic research in association with ASD.
Autism Spectrum Disorder/genetics* ; Cognition ; Genetic Research ; Humans ; Neurodevelopmental Disorders

It is clear that organoids are useful for studying the structure as well as the functions of organs and tissues; they are able to simulate cell-to-cell interactions, symmetrical and asymmetric division, proliferation, and migration of different cell groups. Some progress has been made using brain organoids to elucidate the genetic basis of certain neurodevelopmental disorders. Such as Parkinson's disease and Alzheimer's disease. However, research on organoids in early neural development has received insufficient attention, especially that focusing on neural tube precursors. In this review, we focus on the recent research progress on neural tube organoids and discuss both their challenges and potential solutions.
Humans ; Organoids ; Neural Tube ; Neurodevelopmental Disorders/genetics* ; Brain ; Alzheimer Disease

OBJECTIVES: To analyze the clinical and genetic characteristics of children with autosomal dominant neurodevelopmental disorders caused by kinesin family member 1A (KIF1A) gene variation. METHODS: Clinical and genetic testing data of 6 children with KIF1A gene de novo heterozygous variation diagnosed in Shanghai Children's Medical Center Affiliated to Shanghai Jiao Tong University School of Medicine from the year 2018 to 2020 were retrospectively analyzed. Pathogenic variants were identified based on whole exome sequencing, and verified by Sanger sequencing. Moreover, the effect of variants on three-dimensional structure and stability of protein was analyzed by bioinformatics. RESULTS: Among 6 patients there were 4 males and 2 females, and the age of consultation varied from 7 months to 18 years. All cases had varying degrees of motor developmental delay since childhood, and 4 of them had gait abnormalities or fell easily. In addition, 2 children were accompanied by delayed mental development, epilepsy and abnormal eye development. Genetic tests showed that all 6 cases had heterozygous de novo variations of KIF1A gene, including 4 missense mutations c.296C>T (p.T99M), c.761G>A (p.R254Q), c.326G>T (p.G109V), c.745C>G (p.L249V) and one splicing mutation c.798+1G>A, among which the last three variants have not been previously reported. Bioinformatics analysis showed that G109V and L249V may impair their interaction with the neighboring amino acid residues, thereby impacting protein function and reducing protein stability, and were assessed as "likely pathogenic". Meanwhile, c.798+1G>A may damage an alpha helix in the motor domain of the KIF1A protein, and was assessed as "likely pathogenic". CONCLUSIONS KIF1A-associated neurological diseases are clinically heterogeneous, with motor developmental delay and abnormal gait often being the most common clinical features. The clinical symptoms in T99M carriers are more severe, while those in R254Q carriers are relatively mild.
Male ; Female ; Humans ; Child ; Retrospective Studies ; China ; Mutation ; Epilepsy/genetics* ; Neurodevelopmental Disorders/genetics* ; Kinesins/genetics*

OBJECTIVE: To explore the clinical characteristics and genetic etiology for two children with Neurodevelopmental disorder with hypotonia, stereotypic hand movements, and impaired language (MEDHSIL). METHODS: Two children who had visited the Ningbo Women and Children's Hospital on October 15, 2021 were selected as the study subjects. Whole exome sequencing (WES) was carried out for both patients. Candidate variants were verified by Sanger sequencing of their family members. RESULTS: The two children were respectively found to harbor a heterozygous c.138delC (p.Ile47Serfs*42) variant and a c.833del (p.L278*) variant of the MEF2C gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be pathogenic (PVS1+PS2+PM2_Supporting). CONCLUSION The c.138delC and c.833del variants of the MEF2C gene probably underlay the pathogenesis of MEDHSIL in the two children. Above findings have enriched the mutational spectrum of the MEF2C gene and enabled genetic counseling for their families.
Child ; Humans ; Family ; Genetic Counseling ; Language ; MEF2 Transcription Factors/genetics* ; Muscle Hypotonia/genetics* ; Neurodevelopmental Disorders

Neural development is regulated by both external environment and internal signals, and in addition to transcription factors, epigenetic modifications also play an important role. By focusing on the genetic mechanism of ATP-dependent chromatin remodeling in children with neurodevelopmental disorders, this article elaborates on the effect of four chromatin remodeling complexes on neurogenesis and the development and maturation of neurons and neuroglial cells and introduces the clinical research advances in neurodevelopmental disorders.
Child ; Chromatin ; Chromatin Assembly and Disassembly ; Humans ; Neurodevelopmental Disorders/genetics* ; Neurogenesis ; Transcription Factors/genetics*

BACKGROUND: Significant brain volume deviation is an essential phenotype in children with neurodevelopmental delay (NDD), but its genetic basis has not been fully characterized. This study attempted to analyze the genetic factors associated with significant whole-brain deviation volume (WBDV). METHODS: We established a reference curve based on 4222 subjects ranging in age from the first postnatal day to 18 years. We recruited only NDD patients without acquired etiologies or positive genetic results. Cranial magnetic resonance imaging (MRI) and clinical exome sequencing (2742 genes) data were acquired. A genetic burden test was performed, and the results were compared between patients with and without significant WBDV. Literature review analyses and BrainSpan analysis based on the human brain developmental transcriptome were performed to detect the potential role of genetic risk factors in human brain development. RESULTS: We recruited a total of 253 NDD patients. Among them, 26 had significantly decreased WBDV (<-2 standard deviations [SDs]), and 14 had significantly increased WBDV (>+2 SDs). NDD patients with significant WBDV had higher rates of motor development delay (49.8% [106/213] vs . 75.0% [30/40], P  = 0.003) than patients without significant WBDV. Genetic burden analyses found 30 genes with an increased allele frequency of rare variants in patients with significant WBDV. Analyses of the literature further demonstrated that these genes were not randomly identified: burden genes were more related to the brain development than background genes ( P  = 1.656e -9 ). In seven human brain regions related to motor development, we observed burden genes had higher expression before 37-week gestational age than postnatal stages. Functional analyses found that burden genes were enriched in embryonic brain development, with positive regulation of synaptic growth at the neuromuscular junction, positive regulation of deoxyribonucleic acid templated transcription, and response to hormone, and these genes were shown to be expressed in neural progenitors. Based on single cell sequencing analyses, we found TUBB2B gene had elevated expression levels in neural progenitor cells, interneuron, and excitatory neuron and SOX15 had high expression in interneuron and excitatory neuron. CONCLUSION Idiopathic NDD patients with significant brain volume changes detected by MRI had an increased prevalence of motor development delay, which could be explained by the genetic differences characterized herein.
Child ; Humans ; Neurodevelopmental Disorders/epidemiology* ; Genetic Testing ; Phenotype ; Brain/pathology* ; Genetic Background ; SOX Transcription Factors/genetics*

Mutations of the X-linked methyl-CpG-binding protein 2 (MECP2) gene in humans are responsible for most cases of Rett syndrome (RTT), an X-linked progressive neurological disorder. While genome-wide screens in clinical trials have revealed several putative RTT-associated mutations in MECP2, their causal relevance regarding the functional regulation of MeCP2 at the etiologic sites at the protein level requires more evidence. In this study, we demonstrated that MeCP2 was dynamically modified by O-linked-β-N-acetylglucosamine (O-GlcNAc) at threonine 203 (T203), an etiologic site in RTT patients. Disruption of the O-GlcNAcylation of MeCP2 specifically at T203 impaired dendrite development and spine maturation in cultured hippocampal neurons, and disrupted neuronal migration, dendritic spine morphogenesis, and caused dysfunction of synaptic transmission in the developing and juvenile mouse cerebral cortex. Mechanistically, genetic disruption of O-GlcNAcylation at T203 on MeCP2 decreased the neuronal activity-induced induction of Bdnf transcription. Our study highlights the critical role of MeCP2 T203 O-GlcNAcylation in neural development and synaptic transmission potentially via brain-derived neurotrophic factor.
Animals ; Humans ; Methyl-CpG-Binding Protein 2/metabolism* ; Mice ; Neurodevelopmental Disorders/genetics* ; Rett Syndrome/genetics* ; Synaptic Transmission ; Threonine

OBJECTIVE: To explore the clinical characteristics and genetic variant in a child with neurodevelopmental disorders (NDDs). METHODS: Clinical data of a child who had presented at Xiaogan Hospital Affiliated to Wuhan University of Science and Technology in December 2020 due to intermittent convulsions for over a year were retrospectively analyzed. Peripheral blood samples of the child and his parents were collected and subjected to whole exome sequencing. Candidate variants were verified by Sanger sequencing and bioinformatic analysis. "HNRNPU gene", "epilepsy", "epileptic encephalopathy", "hereditary epilepsy", "neurodevelopmental disorder", "neurodevelopmental syndrome", "HNRNPU", and "NDDs" were used as the key words to search the CNKI, Wanfang and PubMed databases dated from January 1, 1994 to February 10, 2022. RESULTS: The patient was a 2-year-old boy who had developed seizure at the age of 5 months. His clinical features had included abnormal appearance, recurrent seizures, and low developmental quotients of each functional area as evaluated by the Gesell scale. The child was given sodium valproate for the antiepileptic treatment and rehabilitation training. He had become seizure-free within half a year of follow-up, but his intelligence and motor development did not improve significantly. Genetic testing revealed that he has harbored a heterozygous c.1720_1722delCTT (p.Lys574del) variant of the HNRNPU gene, which was not found in either of his parents. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic (PS2+PM2_Supporting+PM4). A total of 13 articles were retrieved, and the types of HNRNPU gene mutations have included splice site mutation, nonsense mutation, missense mutation, in-frame deletion, gene duplication, frameshifting mutation, and multiple exon deletion. The main clinical manifestations have included mental retardation, language delay, global developmental delay, epilepsy, craniofacial deformity, mental and behavioral abnormalities. CONCLUSION The c.1720_1722delCTT variant of the HNRNPU gene probably underlay the NDDs in this child. Above finding has enriched the mutational spectrum of the HNRNPU gene.
Male ; Child ; Humans ; Infant ; Child, Preschool ; Retrospective Studies ; Neurodevelopmental Disorders/genetics* ; Intellectual Disability ; Mutation ; Seizures ; Epilepsy, Generalized

OBJECTIVE: To explore the clinical phenotype and genetic basis of a child with early onset neurodevelopmental disorder with involuntary movement (NEDIM). METHODS: A child who presented at Department of Neurology of Hunan Children's Hospital on October 8, 2020 was selected as the study subject. Clinical data of the child were collected. Genomic DNA was extracted from peripheral blood samples of the child and his parents. Whole exome sequencing (WES) was carried out for the child. Candidate variant was verified by Sanger sequencing and bioinformatic analysis. Relevant literature was searched from the CNKI, PubMed and Google Scholar databases to summarize the clinical phenotypes and genetic variants of the patients. RESULTS: This child was a 3-year-and-3-month boy with involuntary trembling of limbs and motor and language delay. WES revealed that the child has harbored a c.626G>A (p.Arg209His) variant of the GNAO1 gene. Sanger sequencing confirmed that neither of his parents has carried the same variant. The variant had been reported in HGMD and ClinVar databases, but not in the dbSNP, ExAC and 1000 Genomes databases. Prediction with SIFT, PolyPhen-2, and Mutation Taster online software suggested that the variant may be deleterious to the protein function. By UniProt database analysis, the encode amino acid is highly conserved among various species. Prediction with Modeller and PyMOL software indicated that the variant may affect the function of GαO protein. Based on the guideline of the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic. CONCLUSION The GNAO1 gene c.626G>A (p.Arg209His) variant probably underlay the NEDIM in this child. Above finding has expanded the phenotypic spectrum of GNAO1 gene c.626G>A (p.Arg209His) variant and provided a reference for clinical diagnosis and genetic counseling.
Humans ; Computational Biology ; Genetic Counseling ; Genomics ; Mutation ; Neurodevelopmental Disorders/genetics* ; Dyskinesias ; GTP-Binding Protein alpha Subunits, Gi-Go