Mutations in the cyclin-dependent kinase-like 5 gene (CDKL5) cause a severe neurodevelopmental disorder, yet the impact of truncating mutations remains unclear. Here, we introduce the Cdkl5^492stop mouse model, mimicking C-terminal truncating mutations in patients. 492stop/Y mice exhibit altered dendritic spine morphology and spontaneous seizure-like behaviors, alongside other behavioral deficits. After creating cell lines with various Cdkl5 truncating mutations, we found that these mutations are regulated by the nonsense-mediated RNA decay pathway. Most truncating mutations result in CDKL5 protein loss, leading to multiple disease phenotypes, and offering new insights into the pathogenesis of CDKL5 disorder.
Animals ; Disease Models, Animal ; Mice ; Protein Serine-Threonine Kinases/deficiency* ; Mutation/genetics* ; Epileptic Syndromes/genetics* ; Humans ; Dendritic Spines/pathology* ; Spasms, Infantile/genetics* ; Male ; Seizures/genetics* ; Mice, Inbred C57BL

Epilepsy is a chronic neurological disorder affecting ~65 million individuals worldwide. Abnormal synaptic plasticity is one of the most important pathological features of this condition. We investigated how ubiquitin-specific peptidase 47 (USP47) influences synaptic plasticity and its link to epilepsy. We found that USP47 enhanced excitatory postsynaptic transmission and increased the density of total dendritic spines and the proportion of mature dendritic spines. Furthermore, USP47 inhibited the degradation of the ubiquitinated α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit glutamate receptor 1 (GluR1), which is associated with synaptic plasticity. In addition, elevated levels of USP47 were found in epileptic mice, and USP47 knockdown reduced the frequency and duration of seizure-like events and alleviated epileptic seizures. To summarize, we present a new mechanism whereby USP47 regulates excitatory postsynaptic plasticity through the inhibition of ubiquitinated GluR1 degradation. Modulating USP47 may offer a potential approach for controlling seizures and modifying disease progression in future therapeutic strategies.
Animals ; Receptors, AMPA/metabolism* ; Neuronal Plasticity/physiology* ; Seizures/physiopathology* ; Disease Models, Animal ; Mice, Inbred C57BL ; Mice ; Ubiquitin Thiolesterase/genetics* ; Male ; Excitatory Postsynaptic Potentials/physiology* ; Ubiquitination ; Dendritic Spines/metabolism* ; Hippocampus/metabolism*

OBJECTIVE: To explore the genetic etiology of a child with Spastic paraplegia and psychomotor retardation with or without seizures (SPPRS). METHODS: A child who was admitted to the Children's Hospital Affiliated to Nanjing Medical University in April 2022 for motor developmental delay, intellectual disability, and hypertonia was selected as the study subject. Relevant clinical data were retrospectively analyzed. Whole exome sequencing (WES) was carried out for the child and his parents. Candidate variants were searched in the Single Nucleotide Polymorphism Database (dbSNP) and Online Mendelian Inheritance in Man (OMIM) database. Pathogenicity of the variants was assessed based on guidelines from the American College of Medical Genetics and Genomics (ACMG). Using key words such as "HACE1 gene" "Spastic paraplegia and psychomotor retardation with or without seizures" and "SPPRS", previous reports on SPPRS patients due to HACE1 gene variants were retrieved from the CNKI, Wanfang Data Knowledge Service Platform, CQVIP, and PubMed databases, with the time set from January 1, 2000 to April 7, 2024. A mutation map for the HACE1 protein in the patients was created. This study was approved by the Ethics Committee of the Children's Hospital Affiliated to Nanjing Medical University (Ethics No. 202404008-1). RESULTS: The clinical manifestations of the child had included motor developmental delay, intellectual disability and hypertonia. Magnetic resonance imaging revealed hypoplasia of posterior corpus callosum and splenium, with slight enlargement of lateral ventricles. WES revealed that the child has harbored compound heterozygous variants of the HACE1 gene, namely c.535(exon7)_c.538(exon7)delACAG (p.T179fs*5) and c.1678+2(IVS15)T>C, which were respectively inherited from his parents. Based on the guidelines from the ACMG, the variants were respectively rated as likely pathogenic (PVS1 + PM2_Supporting) and pathogenic (PVS1 + PM2_Supporting + PM3). Literature search has identified 8 papers, which reported 23 SPPRS cases due to HACE1 gene variants. All patients exhibited psychomotor developmental delay, among whom 18 HACE1 gene variants were identified. CONCLUSION The c.535(exon7)_c.538(exon7)delACAG (p.T179fs*5) and c.1678+2(IVS15)T>C compound heterozygous variants of the HACE1 gene probably underlay the pathogenesis of SPPRS in this child. Above discovery has enriched the mutational and phenotypic spectrum of the HACE1 gene and provided a reference for clinical diagnosis and genetic counseling.
Humans ; Male ; Seizures/genetics* ; Ubiquitin-Protein Ligases/genetics* ; Heterozygote ; Mutation ; Child ; Child, Preschool ; Paraplegia/genetics* ; Intellectual Disability/genetics* ; Polymorphism, Single Nucleotide ; Exome Sequencing ; Psychomotor Disorders/genetics*

OBJECTIVE: To analyze the clinical characteristics and genetic etiology of a child with Christianson syndrome (CS). METHODS: A 1-year-and-5-month-old boy with CS diagnosed at the First Affiliated Hospital of Zhengzhou University in April 2021 was selected as the study subject. Clinical data were retrospectively analyzed. Peripheral blood samples were obtained from the child and his parents, followed by genomic DNA extraction and whole exome sequencing (WES). Candidate variant was validated by Sanger sequencing. This study has been approved by the Medical Ethics Committee of the Hospital of Zhengzhou University (Ethics No. 2024-KY-1103-001). RESULTS: The child has manifested with seizures, microcephaly, and global developmental delay. WES revealed that he has harbored a novel de novo hemizygous nonsense variant of the SLC9A6 gene, namely c.1014G>A (p.W338*). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic. CONCLUSION The hemizygous c.1014G>A nonsense variant of the SLC9A6 gene probably underlay the pathogenesis in this child. Above discovery has expanded mutational spectrum of the SLC9A6 gene and enabled definite diagnosis of the child.
Humans ; Male ; Infant ; Microcephaly/genetics* ; Spasms, Infantile/genetics* ; Sodium-Hydrogen Exchangers/genetics* ; Exome Sequencing ; Intellectual Disability/genetics* ; Genetic Diseases, X-Linked/genetics* ; Mutation ; Seizures/genetics* ; Ataxia ; Epilepsy ; Ocular Motility Disorders

OBJECTIVE: To explore the clinical characteristics and genetic cause of a child with gastrointestinal hemorrhage and Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) and to review the literature. METHODS: Clinical data of a child with gastrointestinal hemorrhage with CRMCC admitted to the Hepatology Department of Hunan Children's Hospital in September 2019 were collected, and peripheral blood DNA of the child and his parents were analyzed by whole exome sequencing. Candidate variants were validated by Sanger sequencing, followed by bioinformatics analysis, American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants pathogenicity classification, and protein structure prediction. A literature search with "Coats Plus syndrome" or "Cerebroretinal microangiopathy with calcifications and cysts" as keywords was conducted at PubMed, China National Knowledge Infrastructure and Wanfang databases to include recently published studies (up to December 2023). This study has been approved by the Ethics Committee of Hunan Children's Hospital (Ethics No. KY2020-07). Informed consent for clinical research was obtained from the guardian of the child. RESULTS: The proband was a 10-year-10-month-old boy. The clinical manifestations were intrauterine and postnatal growth retardation, gastrointestinal hemorrhage, liver fibrosis, panhemopenia, bilateral exudative retinopathy, intracranial lesions and facial pigmentation. WES and Sanger sequencing revealed two novel heterozygous variants in the CTC1 gene: c.787G>A (p.Val263Met) in exon 5 and c.2930C>G (p.Ser977Cys) in exon 17, which were inherited from his mother and father, respectively. According to ACMG pathogenicity classification, both missense variants were classified as variants of uncertain significance (VUS). Protein structure prediction showed the absence of LIG_SH3_3 motif and LIG_SH3_3 motif, and the p.Ser977Cys mutation may affect the binding between CST (CTC1-STN1-TEN) complex and DNA strand. The child had continued to experience recurrent gastrointestinal bleeding episodes despite propranolol treatment, but the condition was controlled after liver transplantation. According to the predefined literature search strategy of this study, a total of 10 relevant articles on pediatric CRMCC patients were retrieved, involving 11 children with gastrointestinal bleeding. Pharmacological and endoscopic therapies play a certain role in the management of CRMCC children complicated with gastrointestinal bleeding. CONCLUSION The CTC1 gene c.787G>A and c.2930C>G variants probably underlay CRMCC in this child. This study has broadened the variation spectrum of CTC1-related diseases and provided a basis for genetic counseling. Liver transplantation may be an important treatment for gastrointestinal hemorrhage in children who do not respond well to medication and endoscopic therapy.
Humans ; Male ; Gastrointestinal Hemorrhage/genetics* ; Child ; Calcinosis/genetics* ; Cysts/genetics* ; Central Nervous System Cysts/genetics* ; Mutation ; Exome Sequencing ; Leukoencephalopathies ; Retinal Diseases ; Seizures ; Muscle Spasticity ; Brain Neoplasms ; Ataxia

OBJECTIVE: To investigate the clinical and genetic characteristics of a Chinese pedigree affected with Neurodevelopmental disorder with absent language and variable seizures (NEDALVS) due to variant of WASF1 gene, and to review the literature on NEDALVS associated with WASF1 gene variants. METHODS: A 4-year-and-8-month-old boy with NEDALVS diagnosed at Linyi People's Hospital in July 2024 due to "discovering language development delay for more than 2 years" and his family members were selected as the study subjects. Clinical data of the family members were collected. Peripheral venous blood samples were collected from family members. Whole-exome sequencing (WES) was performed, and candidate variants were verified, by Sanger sequencing. Pathogenicity of candidate variant was classified according to the Standards and Guidelines for the Interpretation of Sequence Variants established by the American College of Medical Genetics and Genomics (ACMG). Using the MUpro website, SWISS-MODEL, PyMOL, Clustal X, PolyPhen-2, and Mutation Taster software, bioinformatics analysis of protein three-dimensional structure modeling for gene mutations, cross-species conservation of mutant amino acids, and pathogenicity prediction of mutation sites. Relevant literature was retrieved from databases such as CNKI, Wanfang Data Knowledge Service Platform, and PubMed, and the clinical phenotypes and genotypes of patients with WASF1 gene mutations reported in the literature were summarized and analyzed. This study was approved by the Medical Ethics Committee of Linyi People's Hospital (Ethics No.: YX200303). RESULTS: The proband, a 4-year and 8-month-old male, mainly presented with delayed language and motor development, accompanied by autistic behaviors; the proband's younger brother was 2 years and 7 months old at the time of consultation, mainly presented with delayed language and motor development, accompanied by short stature; the proband's mother mainly presents with limited language expression and poor interpersonal interaction; the proband's maternal grandmother mainly presents with soliloquizing?behavior. The results of WES showed that the proband carried a heterozygous mutation c.214C>T (p.Arg72Cys) in the WASF1 gene, and this site has not been recorded in the database. Sanger sequencing confirmed that the proband's younger brother, mother, and maternal grandmother had harbored the same variant. Based on the guidelines from the ACMG, this variant was rated as likely pathogenic (PM2_Supporting+PP1+PP3+PP4). Through SWISS-MODEL homology modeling and PyMOL structure visualization analysis, it was further confirmed that this variant can lead to a decrease in protein stability. Amino acid sequence conservation analysis of the WASF1 protein using Clustal X software suggested that the c.214C>T (p.Arg72Cys) variant has caused replacement of a highly conserved amino acid. According to the results of PolyPhen-2 and Mutation Taster, the p.Arg72Cys variant was predicted to be a hazardous. By following the retrieval strategy set in this study, a total of 5 research articles regarding to patients with NEDALVS caused by WASF1 gene mutations were retrieved, which involved 15 patients. Combining the proband and their family members discovered in this study, there were a total of 19 NEDALVS patients. The main clinical features included: motor developmental delay (100%, 17/17), language/intellectual developmental delay (100%, 17/17), epilepsy (64.7%, 11/17), autistic behavior (76.5%, 13/17), hypotonia (70.6%, 12/17), abnormal electroencephalogram (64.7%, 11/17), and short stature (17.6%, 3/17). All 19 patients had heterozygous mutations, with 8 mutation sites. Missense mutations were the most common, accounting for 84.2% (16/19). CONCLUSION A pathogenic variant of the WASF1 gene was identified in a pedigree affected with NEDALVS. Discovery of the novel variant has, expanded the mutational spectrum of the WASF1 gene.
Child, Preschool ; Female ; Humans ; Infant ; Male ; China ; Exome Sequencing ; Mutation ; Neurodevelopmental Disorders/genetics* ; Pedigree ; Seizures/genetics* ; East Asian People/genetics*

OBJECTIVE: To explore the clinical and genetic characteristics of a child with intellectual development disorder and seizures due to a variant of AP2M1 gene. METHODS: Clinical data of a child with intellectual development disorder and epilepsy who was admitted to the Department of Pediatric Neurology of the Third Affiliated Hospital of Zhengzhou University in January 2021 were retrospectively analyzed. Peripheral blood samples of the child and his parents were collected for whole exome sequencing. Candidate variant was verified by Sanger sequencing and pathogenicity analysis. The three-dimensional structure of the AP2M1 protein was visualized using Chimera v1.10.1 software. Pathogenicity of candidate variant was classified according to the Standards and Guidelines for the Interpretation of Sequence Variants from the American College of Medical Genetics and Genomics American College of Medical Genetics (ACMG). With "AP2M1 gene" "epilepsy" "intellectual disability" as the keywords, relevant cases were searched from CNKI, Wanfang Data knowledge service platform and PubMed databases with the search time spanning from the establishment of the database to September 2024. This study was approved by the Medical Ethics Committee of the Third Affiliated Hospital of Zhengzhou University (Ethics No.: 2020-57). RESULTS: The child was a 8-years-and-6-months-old boy, who could raise his head at 3 months and sit alone at 8 months old. He could not walk alone at 1 year old and underwent 2 months' rehabilitation treatment, and could walk alone and call his parents at 1-and-a-half-years-old. At 4-years-and-10-months-old, he started to have frequent seizures, manifesting as low level of consciousness, body shaking, accompanied by blinking, lasting about a few seconds several times a day and could be relieved. With the treatment of sodium valproate combined with lamotrigine, the convulsions were controlled, but his movement and cognition were lagged behind. DNA sequencing revealed that he has harbored a novel variant of the AP2M1 gene (NM_004068.3) c.508C>T (p.Arg170Trp). Sanger sequencing confirmed that both of his parents were of the wild-type. According to the guidelines from the American College for Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic (PS2+PS4+PM1+PM2+PP2+PP3). The difference between the wild-type and mutant AP2M1 proteins can be clearly viewed through its three-dimensional structure. Two previous reports have included 5 cases due to the same variant. Common manifestations have included seizures (100%, 5/5), motor retardation (100%, 5/5), intellectual impairment (100%, 5/5), autism spectrum disorder (60%, 3/5), ataxia (100%, 5/5), and special facial features (20%, 1/5). CONCLUSION The c.508C>T (p.Arg170Trp) variant of the AP2M1 gene may underlie the intellectual retardation and seizure in this child.
Humans ; Male ; Child ; Intellectual Disability/genetics* ; Seizures/genetics* ; Exome Sequencing ; Mutation

The patient is a 10-month and 21-day-old girl who began to show developmental delays at 3 months of age, with severe language developmental disorders, stereotyped movements, and easily provoked laughter. Physical examination revealed fair skin and a flattened occiput. At 10 months of age, a video electroencephalogram suggested atypical absence seizures, with migrating slow-wave activity observed during the interictal period. Whole exome sequencing of three family members indicated a novel mutation in the AP2M1 gene, c.508C>T (p.R170W), in the patient. A total of six cases of autosomal dominant intellectual developmental disorder 60 with seizures associated with mutations in the AP2M1 gene have been reported both domestically and internationally (including this study). The main clinical features included developmental delays (6 cases), language developmental disorders (5 cases), stereotyped movements (3 cases), a tendency to smile (1 case), and atypical absence seizures (4 cases). Interictal electroencephalograms showed widespread spike waves and spike-slow wave discharges (5 cases), and migrating slow-wave activity (1 case). The c.508C>T (p.R170W) mutation may be a hotspot for mutations in the AP2M1 gene, and its clinical features are similar to those of Angelman syndrome.
Humans ; Female ; Seizures/genetics* ; Infant ; Mutation ; Intellectual Disability/genetics* ; Electroencephalography ; Developmental Disabilities/genetics*

OBJECTIVE: To analyze the clinical manifestation and genetic basis for four children with delayed onset Ornithine transcarbamylase deficiency (OTCD). METHODS: Clinical data of four children with OTCD admitted to the Children's Hospital of the First Affiliated Hospital of Zhengzhou University from January 2020 to April 2021 were reviewed. Peripheral blood samples of the children and their parents were collected and subjected to whole exome sequencing (WES). Bioinformatic analysis and Sanger sequencing verification were carried out to verify the candidate variants. Impact of the candidate variants on the protein structure was also predicted. RESULTS: The clinical manifestations of the four children included vomiting, convulsion and disturbance of consciousness. WES revealed that the child 1 was heterozygous for a c.421C>T (p.R141X) variant in exon 5, children 2 and 3 were hemizygous for a c.119G>A (p.R40H) variant in exon 2, and child 4 was hemizygous for a c.607T>A (p.S203T) variant in exon 5 of the OTC gene. Among these, the c.607T>A variant was unreported previously and predicted to be pathogenic (PM1+PM2_Supporting+PP3+PP4). Bioinformatic analysis has predicted that the variant may result in breakage of hydrogen bonds and alter the protein structure and function. Sanger sequencing confirmed that the variants in children 2 to 4 have derived from their mothers. CONCLUSION The pathogenic variants of the OTC gene probably underlay the delayed OTCD in 4 children. The discovery of the c.607T>A variant has enriched the mutational spectrum of the OTC gene.
Child ; Humans ; Ornithine Carbamoyltransferase Deficiency Disease/genetics* ; Exons ; Seizures ; Computational Biology ; Heterozygote

OBJECTIVE: To explore the genetic etiology of a patient with epilepsy and provide genetic counseling. METHODS: A patient who had visited the Center for Reproductive Medicine of Shandong University on November 11, 2020 was selected as the study subject, and her clinic information was collected. Candidate variant was identified through whole exome sequencing (WES), and Sanger sequencing was used for validation. Possible transcriptional changes caused by the variant was detected by reverse transcription-PCR and Sanger sequencing. RESULTS: The patient was a 35-year-old female with no fever at the onset, loss of consciousness and abnormal firing in the temporal lobe, manifesting predominantly as convulsions and fainting. WES revealed that she had harbored a heterozygous c.2841+5G>A variant of the SCN9A gene, which was verified by Sanger sequencing. cDNA sequencing confirmed that 154 bases were inserted between exons 16 and 17 of the SCN9A gene, which probably produced a truncated protein and affected the normal function of the SCN9A protein. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.2841+5G>A variant was classified as likely pathogenic (PVS1_Strong+PM2_Supporting). CONCLUSION The c.2841+5G>A variant of the SCN9A gene probably underlay the epilepsy in this patient. Above finding has enriched the variant spectrum of the SCN9A gene and provided a basis for the prenatal diagnosis and preimplantation genetic testing for this patient.
Humans ; Female ; Pregnancy ; Adult ; Epilepsy/genetics* ; Seizures ; Exons ; DNA, Complementary ; Genetic Counseling ; NAV1.7 Voltage-Gated Sodium Channel