OBJECTIVE: To delineate the clinical and genetic features of a Chinese girl harboring a rare de novo variant of SYNGAP1 associated with Mental retardation, autosomal dominant 5 (MRD5), and to conduct a comprehensive genotype-phenotype correlation analysis within the Chinese population through an extensive literature review. METHODS: A 5-year-old girl presenting with seizures without an obvious cause was enrolled in September 2020. Genomic DNA was extracted from the patient and her parents. Whole exome sequencing (WES) was performed on the proband to identify suspected pathogenic variants based on her clinical phenotype. Sanger sequencing was used for validation, followed by bioinformatic analysis of the variant. Additionally, data from 54 previously reported Chinese cases with SYNGAP1 variants were integrated to summarize the distribution of variant types and clinical characteristics. Ethical approval was obtained from the Ethics Committee of Kunming Children's Hospital (Ethics No.: 2021-03-055-K01). RESULTS: WES identified a heterozygous nonsense variant, SYNGAP1 c.725G>A (p.Trp242*), in the proband. Sanger sequencing confirmed it was a de novo variant. According to the ACMG guidelines, this variant was classified as pathogenic (PVS1+PS2). Based on the clinical manifestations, the patient was diagnosed with MRD5. Bioinformatic analysis suggested that this variant introduces a premature stop codon at tryptophan 242, disrupting the PH domain and leading to the loss of the C2, Ras-GAP, and C-terminal domains. The pooled analysis of Chinese cases revealed that nonsense (38.2%) and frameshift (36.4%) variants were the predominant types. Intellectual disability/developmental delay was present in 100.0% of patients, epilepsy in 83.6%, and autism spectrum disorder in 41.3%. The incidence of epilepsy differed significantly among variant types (P = 0.045). Exons 8 and 15 were identified as mutation hotspots. CONCLUSION This study has identified a SYNGAP1 c.725G>A variant in the Chinese population and confirmed it as a potential cause of MRD5, which expanded the mutational spectrum of this disorder.
Humans ; Female ; Child, Preschool ; Intellectual Disability/genetics* ; ras GTPase-Activating Proteins/genetics* ; Phenotype ; Exome Sequencing ; Genetic Association Studies

OBJECTIVE: To investigate the clinical manifestations and genetic etiology of a fetus with Neurodevelopmental disorders with deformed facial features and distal skeletal abnormalities (NEDDFSA). METHODS: Clinical data of a NEDDFSA fetus diagnosed at the Affiliated Women and Children's Hospital Affiliated to Ningbo University in March 2025 was selected as the study subject. Whole-exome sequencing (WES) was carried out on the amniotic fluid and parental peripheral blood samples, and candidate variants was verified by Sanger sequencing. The pathogenicity of candidate variant was rated based on guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: EC2023-094). RESULTS: At 30 weeks of gestation, the fetus was found to have microcephaly, short femur and intrauterine growth restriction. WES revealed that the fetus harbored a de novo heterozygous frameshift variant c.2633dup (p.Gly879ArgfsTer22) of the ZMIZ1 gene, which was rated as pathogenic (PM2_Supporting+PS2_Supporting+PVS1). Combined with 25 cases from the literature, the main manifestations of patients have included intellectual disability, growth retardation and cranio-limb skeletal dysplasia, albeit without clear genotype-phenotype correlation. CONCLUSION The de novo variant c.2633dup (p.Gly879ArgfsTer22) of the ZMIZ1 gene probably underlay the NEDDFSA in this fetus. Genetic testing has enabled accurate prenatal diagnosis and provided evidence for genetic counseling and reproductive guidance of this family.
Humans ; Female ; Pregnancy ; Neurodevelopmental Disorders/genetics* ; Transcription Factors/genetics* ; Fetus/abnormalities* ; Exome Sequencing ; Prenatal Diagnosis

OBJECTIVES: To summarize the clinical manifestations and genetic characteristics of creatine deficiency syndrome (CDS) caused by GAMT gene mutations. METHODS: A retrospective analysis was conducted on the clinical and genetic data of two children diagnosed with GAMT deficiency-type CDS at the Children's Medical Center of Xiangya Hospital, Central South University, from December 2020 to December 2024. RESULTS: The two patients presented with symptoms in infancy, and both had compound heterozygous mutations in the GAMT gene. Case 1 exhibited seizures and intellectual disability, while Case 2 had intellectual disability and attention-deficit hyperactivity disorder. Magnetic resonance spectroscopy of cranial MRI in both patients indicated reduced creatine peaks. After creatine treatment, seizures in Case 1 were controlled, but both patients continued to experience intellectual disabilities and behavioral issues. As of December 2024, a total of 21 cases have been reported in China (including this study), and 115 cases have been reported abroad. All patients exhibited developmental delay or intellectual disabilities, with 66.9% (91/136) experiencing seizures, 33.8% (46/136) presenting with motor disorders, and 36.8% (50/136) having behavioral problems. Seventy-five percent (102/136) of patients received creatine treatment, leading to significant improvements in seizures and motor disorders, although cognitive improvement was not substantial. CONCLUSIONS GAMT deficiency-type CDS is rare and presents with nonspecific clinical features. Timely diagnosis facilitates targeted treatment, which can partially improve prognosis.
Child ; Female ; Humans ; Male ; Creatine/deficiency* ; Guanidinoacetate N-Methyltransferase/deficiency* ; Intellectual Disability/genetics* ; Mutation ; Retrospective Studies ; Rhabdomyolysis/genetics* ; Language Development Disorders ; Movement Disorders/congenital*

The patient is a male neonate born at term. He was admitted 16 minutes after birth due to stridor and inspiratory respiratory distress. Physical examination revealed a cleft palate, and a grade II systolic ejection murmur was audible at the left sternal border. Whole exome sequencing identified a heterozygous variant in the SON gene, c.5753-5756del (p.Val1918GlufsTer87), which was absent in either parent, indicating a de novo mutation. According to the guidelines of the American College of Medical Genetics and Genomics, this was classified as a "pathogenic variant" leading to a diagnosis of Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome. Upon admission, symptomatic supportive treatment was provided. Follow-up at the age of 8 months revealed persistent stridor; the infant could only consume small amounts of milk and was unable to sit steadily. This patient represents the youngest reported case to date, and his symptoms expand the clinical spectrum of the disease, providing valuable insights for clinical diagnosis and treatment.
Humans ; Infant, Newborn ; Male ; Minor Histocompatibility Antigens/genetics* ; DNA-Binding Proteins/genetics* ; Rare Diseases/genetics* ; Neurodevelopmental Disorders/genetics*

OBJECTIVES: To summarize the clinical and genetic characteristics of epilepsy with intellectual disability caused by SETD1B gene variants in children. METHODS: A retrospective analysis was conducted on the clinical data of three children with SETD1B gene variants diagnosed and treated at the Department of Pediatric Neurology of Xiangya Hospital of Central South University. Relevant literature was reviewed to summarize the clinical characteristics of this condition. RESULTS: All three children presented with symptoms during infancy or early childhood, including mild intellectual disability and myoclonic seizures, with two cases exhibiting eyelid myoclonia. After treatment with three or more antiepileptic drugs, two cases achieved seizure control or partial control, while one case remained refractory. Each of the three children was found to have a heterozygous variant in the SETD1B gene (one deletion, one frameshift, and one missense variant). To date, 54 cases with SETD1B gene variants have been reported, involving a total of 56 variants, predominantly missense variants (64%, 36/56). The main clinical manifestations included varying degrees of developmental delay (96%, 52/54) and seizures (81%, 44/54). Among the 44 patients with seizures, myoclonic (20%, 9/44) and absence seizures (34%, 15/44) were common, with eyelid myoclonia reported in six cases. Approximately one-fifth of these patients had poorly controlled seizures. CONCLUSIONS The primary phenotypes associated with SETD1B gene variants are intellectual disability and seizures, and seizures exhibit distinct characteristics. Eyelid myoclonia is not uncommon.
Humans ; Intellectual Disability/complications* ; Epilepsy/complications* ; Male ; Female ; Histone-Lysine N-Methyltransferase/genetics* ; Child, Preschool ; Child ; Retrospective Studies

A 7-year-old girl was admitted to the hospital with rapidly progressive vision loss. Since 1 year of age, she had exhibited developmental delay accompanied by visual impairment and neutropenia. Combined with genetic testing and molecular pathogenicity analysis, she was diagnosed with Cohen syndrome (CS) caused by compound heterozygous variants in VPS13B (c.6940+1G>T and c.2911C>T). The c.6940+1G>T variant resulted in exon 38 skipping, leading to a frameshift and premature termination. Reverse transcription quantitative polymerase chain reaction revealed significantly reduced VPS13B gene expression (P<0.05). Bioinformatic analysis suggested that both variants likely produce truncated proteins. This case highlights that integrating clinical features with molecular pathogenicity assessment (DNA, RNA, and protein analysis) can improve early diagnostic accuracy for CS.
Humans ; Female ; Child ; Vesicular Transport Proteins/genetics* ; Developmental Disabilities/etiology* ; Muscle Hypotonia/etiology* ; Myopia/etiology* ; Heterozygote ; Intellectual Disability/etiology* ; Microcephaly/etiology* ; Obesity/genetics* ; Growth Disorders/etiology* ; Retinal Degeneration/genetics* ; Psychomotor Disorders/genetics* ; Fingers/abnormalities*

This article reports the clinical features and gene mutation types of a large family with Nascimento form of syndromic X-linked intellectual developmental disorder (MRXSN), involving 9 individuals across 3 generations, and a literature review was conducted. In this family, 9 individuals had similar manifestations including mental retardation and unusual facies, and 4 of them had passed away. Genetic testing showed that the proband had the deletion of exons 2-3 of the UBE2A gene, which was inherited from the mother. Fluorescent quantitative polymerase chain reaction showed that the proband and his uncle had the deletion of exons 2-3 of the UBE2A gene; the proband's mother, grandmother, and great-aunt had a heterozygous deletion of exons 2-3 of the UBE2A gene; the proband's father, sister, and aunt had a normal copy number of exons 2-3 of the UBE2A gene. The 34 patients reported in the literature had diverse clinical phenotypes, and UBE2A gene mutations (22/34, 65%) and large fragment deletions (12/34, 35%) were the main mutation types. Moderate to severe mental retardation (34/34, 100%), speech and language impairment (33/34, 97%), and unusual facies (32/34, 94%) were the main clinical manifestations of MRXSN patients. The disease has obvious phenotypic heterogeneity, and early diagnosis facilitates optimal prenatal and postnatal management to improve reproductive outcomes.
Humans ; Male ; Ubiquitin-Conjugating Enzymes/genetics* ; Female ; X-Linked Intellectual Disability/genetics* ; Gene Deletion ; Child ; Pedigree ; Child, Preschool ; Adult

Patient 1, a 3-year-6-month-old male, presented with feeding difficulties and delayed motor development. He exhibited poor responsiveness at birth, weak crying, intellectual and motor delays, low immunity, recurrent respiratory infections, hypotonia of the limbs, and distinctive facial features (low-set ears, double chin, and high arched palate), as well as a single transverse palmar crease on the right hand. Genetic testing revealed a c.1096C>T heterozygous variant in the SMARCB1 gene. Patient 2, a 3-year-old male, presented with developmental delay and distinctive facial features. Genetic testing identified the same pathogenic mutation as in Patient 1. The two patients are unrelated, and clinical phenotyping and genetic testing confirmed both cases as Coffin-Siris syndrome type 3. Coffin-Siris syndrome is a rare genetic disorder, and early genetic testing can aid in diagnosis.
Child, Preschool ; Humans ; Male ; Abnormalities, Multiple/genetics* ; Chromosomal Proteins, Non-Histone/genetics* ; Ear/abnormalities* ; Face/abnormalities* ; Hand Deformities, Congenital/genetics* ; Intellectual Disability/genetics* ; Micrognathism/genetics* ; Mutation ; Neck/abnormalities*

OBJECTIVES: To investigate the disease burden of attention-deficit/hyperactivity disorder (ADHD) among children and adolescents in China and to predict future trends, in order to provide evidence for disease control strategies. METHODS: Based on data from the Global Burden of Disease Study 2021 (GBD 2021), joinpoint regression and prediction models were constructed to analyze and forecast the trends in ADHD burden indicators among Chinese children and adolescents from 1990 to 2021. RESULTS: In 2021, the incidence, prevalence, and disability-adjusted life years (DALYs) rates of ADHD among children and adolescents in China increased by 41.46%, 21.44%, and 21.75%, respectively, compared to 1990. From 1990 to 2021, the disease burden of ADHD showed an overall upward trend across sex and age groups, with a heavier burden among males. The highest incidence was observed in children aged 5-9 years, while the highest prevalence and DALY rates were found in those aged 10-14 years. By 2031, the incidence, prevalence, and DALY rates of ADHD among Chinese children and adolescents are projected to reach 324.88 per 100 000, 3 762.36 per 100 000, and 45.85 per 100 000, respectively. CONCLUSIONS From 1990 to 2021, the incidence, prevalence, and DALY rates of ADHD among children and adolescents in China have all increased, suggesting that more proactive prevention and intervention measures may be needed to alleviate the disease burden of ADHD in this population.
Humans ; Child ; Adolescent ; Attention Deficit Disorder with Hyperactivity/epidemiology* ; Male ; Female ; Child, Preschool ; China/epidemiology* ; Cost of Illness ; Prevalence ; Incidence ; Disability-Adjusted Life Years ; Forecasting ; East Asian People

OBJECTIVES: To investigate the relationship between the polygenic risks for various psychiatric disorders and clinical and neuropsychological characteristics in children with attention-deficit/hyperactivity disorder (ADHD). METHODS: Using a cross-sectional design, 285 children with ADHD and 107 healthy controls were assessed using the Child Behavior Checklist, the Behavior Rating Inventory of Executive Function for parents, the Wechsler Intelligence Scale for Children, Fourth Edition, and the Cambridge Neuropsychological Test Automated Battery. Blood samples were collected for genetic data. Polygenic risk scores (PRSs) for various psychiatric disorders were calculated using the PRSice-2 software. RESULTS: Compared with the healthy controls, the children with ADHD displayed significantly higher PRSs for ADHD, major depressive disorder, anxiety disorder, and obsessive-compulsive disorder (P<0.05). In terms of daily-life executive function, ADHD-related PRS was significantly correlated with the working memory factor; panic disorder-related PRS was significantly correlated with the initiation factor; bipolar disorder-related PRS was significantly correlated with the shift factor; schizophrenia-related PRS was significantly correlated with the inhibition, emotional control, initiation, working memory, planning, organization, and monitoring factors (P<0.05). The PRS related to anxiety disorders was negatively correlated with total IQ and processing speed index (P<0.05). The PRS related to obsessive-compulsive disorder was negatively correlated with the processing speed index and positively correlated with the stop-signal reaction time index of the stop-signal task (P<0.05). CONCLUSIONS PRSs for various psychiatric disorders are closely correlated with the behavioral and cognitive characteristics in children with ADHD, which provides more insights into the heterogeneity of ADHD.
Humans ; Attention Deficit Disorder with Hyperactivity/genetics* ; Child ; Male ; Female ; Cross-Sectional Studies ; Neuropsychological Tests ; Multifactorial Inheritance ; Adolescent ; Mental Disorders/etiology* ; Executive Function ; Genetic Risk Score