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*

OBJECTIVE: To explore the clinical features, genetic characteristics in a child with Miller-McKusick-Malvaux syndrome (3MS) type 1 caused by CUL7 gene variant. METHODS: A child diagnosed with 3MS type 1 at the Children's Hospital Affiliated to Zhengzhou University in February 2021 was selected as the subject of this study. Peripheral blood samples were collected from the child and her parents for genomic DNA extraction. Whole exome sequencing (WES) was performed on the child, and Sanger sequencing was used to validate the candidate variants and analyze their pathogenicity. A literature search was conducted using the keywords "3M syndrome" in the China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, and PubMed databases from inception to December 2024. The clinical data of Chinese children with 3MS reported in the literature were summarized. This study was approved by the Medical Ethics Committee of the Children's Hospital Affiliated to Zhengzhou University (Ethics No. 2024-K-020). RESULTS: The child was a 6-year-old and 2-month-old female with facial dysmorphism, skeletal abnormalities, and growth and developmental delay. WES revealed compound heterozygous variants in the CUL7 gene: c.2686G>T (p.E896*) and c.1200delT (p.R401Gfs66). Sanger sequencing confirmed that these two variants were inherited from the child's father and mother, respectively. According to the American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants, c.2686G>T (p.E896) was classified as a pathogenic (PVS1+PM2_Supporting+PM3), and c.1200delT (p.R401Gfs*66) was classified as a likely pathogenic (PVS1+PM2_Supporting). Based on the literature search strategy, 18 relevant articles were identified, including a total of 32 Chinese cases of 3MS, of which 8 were fetuses. A total of 32 Chinese 3MS cases were included in the literature review, of which 8 were fetuses. The majority of these cases carried variants in the CUL7 gene (20/32, 62.5%) and OBSL1 gene (12/32, 37.5%). The main clinical manifestations included intrauterine or postnatal growth and developmental delay (32/32, 100.0%), triangular facies (27/32, 84.3%), and skeletal abnormalities (21/32, 65.6%). CONCLUSION The compound heterozygous variants c.2686G>T (p.E896*) and c.1200delT (p.R401Gfs*66) in the CUL7 gene are likely the genetic cause of 3MS type 1 in the child. For children presenting with facial dysmorphism, skeletal abnormalities, and intrauterine or postnatal growth and developmental delay, 3MS should be considered as a differential diagnosis.
Humans ; Cullin Proteins/genetics* ; Female ; Child ; Limb Deformities, Congenital/genetics* ; Exome Sequencing ; Mutation ; Child, Preschool ; Dwarfism ; Muscle Hypotonia ; Spine/abnormalities*

OBJECTIVE: To explore the genetic basis for a boy affected with Cohen syndrome. METHODS: A boy admitted to Children's Hospital of Nanjing Medical University in January 2021 was selected as the study subject. Genome DNA was extracted from peripheral blood samples from the child and his parents. Whole exome sequencing (WES) was carried out. And candidate variants were verified by Sanger sequencing. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 202106060-1). RESULTS: WES revealed that the child has harbored compound heterozygous variants of the VPS13B gene, namely c.1563+1G>A and c.3007insC (p.A1003Afs*13), which were inherited from his mother and father, respectively. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were rates as pathogenic. The c.3007insC (p.A1003Afs*13) was unreported previously. CONCLUSION The compound heterozygous variants c.1563+1G>A and c.3007insC (p.A1003Afs*13) of the VPS13B gene probably underlay the pathogenesis of Cohen syndrome in this child. Above finding has enriched the mutational spectrum of VPS13B gene.
Humans ; Male ; Vesicular Transport Proteins/genetics* ; Intellectual Disability/genetics* ; Muscle Hypotonia/genetics* ; Microcephaly/genetics* ; Fingers/abnormalities* ; Myopia/genetics* ; Obesity/genetics* ; Developmental Disabilities/genetics* ; Mutation ; Exome Sequencing ; Child ; Heterozygote ; Retinal Degeneration

Here, we report a previously unrecognized syndromic neurodevelopmental disorder associated with biallelic loss-of-function variants in the RBM42 gene. The patient is a 2-year-old female with severe central nervous system (CNS) abnormalities, hypotonia, hearing loss, congenital heart defects, and dysmorphic facial features. Familial whole-exome sequencing (WES) reveals that the patient has two compound heterozygous variants, c.304C>T (p.R102*) and c.1312G>A (p.A438T), in the RBM42 gene which encodes an integral component of splicing complex in the RNA-binding motif protein family. The p.A438T variant is in the RRM domain which impairs RBM42 protein stability in vivo. Additionally, p.A438T disrupts the interaction of RBM42 with hnRNP K, which is the causative gene for Au-Kline syndrome with overlapping disease characteristics seen in the index patient. The human R102* or A438T mutant protein failed to fully rescue the growth defects of RBM42 ortholog knockout ΔFgRbp1 in Fusarium while it was rescued by the wild-type (WT) human RBM42. A mouse model carrying Rbm42 compound heterozygous variants, c.280C>T (p.Q94*) and c.1306_1308delinsACA (p.A436T), demonstrated gross fetal developmental defects and most of the double mutant animals died by E13.5. RNA-seq data confirmed that Rbm42 was involved in neurological and myocardial functions with an essential role in alternative splicing (AS). Overall, we present clinical, genetic, and functional data to demonstrate that defects in RBM42 constitute the underlying etiology of a new neurodevelopmental disease which links the dysregulation of global AS to abnormal embryonic development.
Female ; Animals ; Mice ; Humans ; Child, Preschool ; Intellectual Disability/genetics* ; Heart Defects, Congenital/genetics* ; Facies ; Cleft Palate ; Muscle Hypotonia

OBJECTIVE: To explore the clinical features and genetic etiology of a child with Multiple congenital malformations-hypotonia-epilepsy syndrome type 3 (MCAHS3) and provide prenatal diagnosis for her parents. METHODS: A female child who had presented at Linyi People's Hospital on 27 July 2022 for recurrent convulsions for over 4 years was selected as the study subject. Clinical data of the child were collected. Peripheral blood samples were taken from the child and her parents and subjected for whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing. Prenatal diagnosis was carried out on amniotic fluid sample at 18 weeks' gestation. Bioinformatic software was used to analyze the pathogenicity of the protein model for the variant loci. RESULTS: The child was a 4-year-old female with frequent seizures, peculiar facial appearance, hypotonia and severe developmental delay. Genetic analysis revealed that she has harbored compound heterozygous variants of the PIGT gene, namely c.1126del (p.H376Tfs*56) and c.1285G>C (p.E429Q), which were respectively inherited from her mother and father. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.1126del (p.H376Tfs*56) variant was predicted to be pathogenic (PVS1+PM2_Supporting+PM4), and c.1285G>C (p.E429Q) variant was predicted to be likely pathogenic (PM2_Supporting+PM3+PM4). Prenatal diagnosis suggested that the fetus also harbored the same compound heterozygous variants, and the pregnancy was terminated with induced labor. CONCLUSION The c.1126del (p.H376Tfs*56) and c.1285G>C (p.E429Q) compound heterozygous variants of the PIGT gene probably underlay the MCAHS3 in this patient, and prenatal diagnosis has prevented birth of further affected child in this family.
Humans ; Female ; Child ; Pregnancy ; Child, Preschool ; Muscle Hypotonia/genetics* ; Prenatal Diagnosis ; Computational Biology ; Epileptic Syndromes ; Facies

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

OBJECTIVE: To analyze the clinical features of 3M syndrome and effect of growth hormone therapy. METHODS: Clinical data of four children diagnosed with 3M syndrome by whole exome sequencing at Hunan Children's Hospital from January 2014 to February 2022 were retrospectively analyzed, which included clinical manifestation, results of genetic testing and recombinant human growth hormone (rhGH) therapy. A literature review was also carried our for Chinese patients with 3M syndrome. RESULTS: The clinical manifestations of the 4 patients included severe growth retardation, facial dysmorphism and skeletal malformations. Two patients were found to harbor homozygous variants of CUL7 gene, namely c.4717C>T (p.R1573*) and c.967_993delinsCAGCTGG (p.S323Qfs*33). Two patients were found to harbor 3 heterozygous variants of the OBSL1 gene including c.1118G>A (p.W373*), c.458dupG (p.L154Pfs*1002) and c.690dupC (p.E231Rfs*23), among which c.967_993delinsCAGCTGG and c.1118G>A were unreported previously. Eighteen Chinese patients with 3M syndrome were identified through the literature review, including 11 cases (11/18, 61.1%) carrying CUL7 gene variants and 7 cases (7/18, 38.9%) carrying OBSL1 gene variants. The main clinical manifestations were in keeping with previously reported. Four patients were treated with growth hormone, 3 showed obvious growth acceleration, and no adverse reaction was noted. CONCLUSION 3M syndrome has a typical appearance and obvious short stature. To attain accurate diagnosis, genetic testing should be recommended for children with a stature of less than -3 SD and facial dysmorphism. The long-term efficacy of growth hormone therapy for patients with 3M syndrome remains to be observed.
Humans ; Child ; Retrospective Studies ; Dwarfism/genetics* ; Muscle Hypotonia/genetics* ; Growth Hormone/therapeutic use* ; Cytoskeletal Proteins/genetics*

OBJECTIVE: To explore the clinical features and genetic basis of a child with Galactosemia. METHODS: A child who had presented at the Children's Hospital Affiliated to Zhengzhou University on November 20, 2019 was selected as the study subject. Clinical data of the child was collected. Whole exome sequencing was carried out for the child. Candidate variants were validated by Sanger sequencing. RESULTS: Clinical manifestations of the child have included anemia, feeding difficulty, jaundice, hypomyotonia, abnormal liver function and coagulation abnormality. Tandem mass spectrometry showed increased citrulline, methionine, ornithine and tyrosine. Urine organic acid analysis showed increased phenyllactic acid, 4-hydroxyphenylacetic acid, 4-hydroxyphenyllactic acid, 4-hydroxyphenylpyruvate and N-acetyltyrosine. Genetic testing revealed that the child has harbored compound heterozygous variants of the GALT gene, namely c.627T>A (p.Y209*) and c.370G>C (p.G124R), which were respectively inherited from her healthy parents. Among these, c.627T>A (p.Y209*) was known as a likely pathogenic variant, while c.370G>C (p. G124R) was unreported previously and also predicted as a likely pathogenic variant(PM1+PM2_Supporting+PP3_Moderate+PPR). CONCLUSION Above discovery has expanded the spectrum of the GALT gene variants underlying Galactosemia. Patients with thrombocytopenia, feeding difficulties, jaundice, abnormal liver function and coagulation abnormality without obvious causes should be analyzed by screening of metabolic diseases in combination with genetic testing.
Child ; Female ; Humans ; Galactosemias/genetics* ; Genetic Testing ; Health Status ; Methionine ; Muscle Hypotonia ; Mutation

OBJECTIVE: To explore the genetic etiology of a child with D bifunctional protein deficiency (DBPD) born to a consanguineous pedigree. METHODS: A child with DBPD who was admitted to the First Affiliated Hospital of Hainan Medical College on January 6, 2022 due to hypotonia and global developmental delay was selected as the study subject. Clinical data of her pedigree members were collected. Peripheral blood samples of the child, her parents and elder sisters were collected and subjected to whole exome sequencing. Candidate variant was validated by Sanger sequencing and bioinformatic analysis. RESULTS: The child, a 2-year-and-9-month-old female, had featured hypotonia, growth retardation, unstable head lift, and sensorineural deafness. Serum long-chain fatty acids were elevated, and auditory brainstem evoked potentials had failed to elicit V waves in both ears with 90 dBnHL stimulation. Brain MRI revealed thinning of corpus callosum and white matter hypoplasia. The child's parents were secondary cousins. Their elder daughter had a normal phenotype and no clinical symptoms related to DBPD. Elder son had frequent convulsions, hypotonia and feeding difficulties after birth, and had died one and a half month later. Genetic testing revealed that the child had harbored homozygous c.483G>T (p.Gln161His) variants of the HSD17B4 gene, for which both of her parents and elder sisters were carriers. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.483G>T (p.Gln161His) was rated as a pathogenic variant (PM1+PM2_Supporting+PP1+PP3+PP4). CONCLUSION The homozygous c.483G>T (p.Gln161His) variants of the HSD17B4 gene caused by the consanguineous marriage probably underlay the DBPD in this child.
Female ; Humans ; Pedigree ; Muscle Hypotonia ; Hearing Loss, Sensorineural ; Protein Deficiency ; Mutation

OBJECTIVES: To study the clinical and genetic features of Joubert syndrome (JS) in children. METHODS: A retrospective analysis was performed on the clinical data, genetic data, and follow-up data of 20 children who were diagnosed with JS in the Department of Children's Rehabilitation, the Third Affiliated Hospital of Zhengzhou University, from January 2017 to July 2022. RESULTS: Among the 20 children with JS, there were 11 boys and 9 girls. The common clinical manifestations were developmental delay (20 children, 100%), abnormal eye movement (19 children, 95%), and hypotonia (16 children, 80%), followed by abnormal respiratory rhythm in 5 children (25%) and unusual facies (including prominent forehead, low-set ears, and triangular mouth) in 3 children (15%), and no limb deformity was observed. All 20 children (100%) had the typical "molar tooth sign" and "midline cleft syndrome" on head images, and 6 children (30%) had abnormal eye examination results. Genetic testing was performed on 7 children and revealed 6 pathogenic genes, i.e., the CPLANE1, RPGRIP1L, MKS1, CC2D2A, CEP120, and AHI1 genes. CONCLUSIONS For children with developmental delay, especially those with abnormal eye movement and hypotonia, it is recommended to perform a head imaging examination to determine the presence or absence of "molar tooth sign" and "midline cleft syndrome", so as to screen for JS to avoid missed diagnosis and misdiagnosis. There are many pathogenic genes for JS, and whole-exome sequencing can assist in the diagnosis of JS.
Male ; Female ; Humans ; Child ; Cerebellum ; Abnormalities, Multiple/genetics* ; Kidney Diseases, Cystic/genetics* ; Eye Abnormalities/genetics* ; Retina ; Retrospective Studies ; Muscle Hypotonia/genetics*