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*

Global developmental delay (GDD) and intellectual disability (ID) refer to deficits in cognitive and adaptive functioning that arise during the developmental period. GDD/ID is often accompanied by complex developmental abnormalities, with congenital craniofacial malformations being among the most common, such as craniosynostosis, cleft lip and palate, and congenital tooth agenesis. However, the underlying mechanisms of GDD/ID associated with congenital craniofacial malformations remain unclear. With the increasing number of reported genetic syndromes, genetic factors are emerging as key contributors to the concurrent abnormalities in brain and craniofacial development. Studies have identified Wnt, SHH, FGF, and BMP as classical regulatory molecules in craniofacial development, and their roles have also been closely linked to various stages of brain development. This review focuses on the regulatory roles of Wnt, SHH, FGF, and BMP signaling pathways in brain and craniofacial development, as well as the pathogenic mechanisms underlying their association with GDD/ID and craniofacial malformations. The aim is to provide new insights into the etiology of GDD/ID combined with congenital craniofacial malformations.
Humans ; Craniofacial Abnormalities/complications* ; Signal Transduction ; Developmental Disabilities/metabolism* ; Intellectual Disability/complications* ; Animals ; Hedgehog Proteins/genetics* ; Fibroblast Growth Factors/genetics*

OBJECTIVE: To explore the clinical features and management of a child with Chitayat syndrome. METHODS: A child presented at the Fengqing People's Hospital on August 8 2019 was selected as the study subject. Clinical data of the child were retrospectively analyzed. Peripheral blood samples were collected from the child and his father and sister. Whole-exome sequencing (WES) was carried out. Candidate variant was verified by Sanger sequencing. Genome Browser, AlphaFold, and PolyPhen-2 were employed for protein structure simulation and amino acid sequence conservation analysis. Pathogenicity of the variant was rated based on guidelines from the American College of Medical Genetics and Genomics (ACMG). Literature was retrieved from databases including CNKI, Wanfang, and PubMed using the keyword "Chitayat syndrome". The clinical characteristics and prognosis of patients with Chitayat syndrome were reviewed and analyzed. This study was approved by the Ethics Committee the Seventh Affiliated Hospital of Sun Yat-sen University (Ethics No.: KY-2024-086-01). RESULTS: The child was born at full term and had special facial features, skeletal abnormalities, recurrent respiratory tract infections and global developmental delay. WES and Sanger sequencing revealed that he has harbored a heterozygous c.266A>G p.(Tyr89Cys) variant of the ERF gene. Protein structure modeling suggested that the mutant protein has increased spatial distance between the side chain group and DNA, which may reduce its binding affinity to DNA. Amino acid sequence analysis indicated that the p.Tyr89 residue is highly conserved across multiple species. The variant was therefore classified as pathogenic (PM1+PM2_Supporting+PM6+PS1+PP3). The patient was diagnosed with "Chitayat syndrome". Nutritional support and rehabilitation training were recommended, though the child had died of severe pneumonia at 13 months old. Literature retrieval has collected 7 relevant articles, which involved 14 cases of Chitayat syndrome confirmed by genetic testing. Together with our case, all patients had facial dysmorphisms and skeletal deformities. Fourteen patients (93.3%) had respiratory distress. Seven of them (46.7%) had recurrent respiratory infections and 7 (46.7%) were confirmed with respiratory tract malacia. Eight (53.3%) patients had neuropsychological retardation, while 8 (53.3%) had growth delay. The main interventions for Chitayat syndrome include respiratory and nutritional support, and rehabilitation training for developmental delays. CONCLUSION Chitayat syndrome is rarely seen and its clinical manifestations may vary. Airway management and early intervention of developmental delay are important for improving the prognosis.
Humans ; Male ; Exome Sequencing ; Female ; Mutation ; Child, Preschool ; Infant ; Developmental Disabilities/genetics*

OBJECTIVE: To analyze the clinical manifestations and genotype of a child with You-Hoover-Fong syndrome (YHFS) to enhance clinical understanding of this disease. METHODS: Clinical data of a child who visited the Department of Pediatric Neurorehabilitation of the Women's and Children's Hospital Affiliated to Xiamen University in March 2025 for global developmental delay was collected. Peripheral blood samples of the child and his parents were collected for chromosomal microarray analysis and whole exome sequencing (WES). Sanger sequencing was performed for parental validation, and candidate variant was assessed for pathogenicity. Clinical and genetic analyses were conducted based on the child's phenotype. A literature review was performed by retrieving previously reported cases of YHFS due to TELO2 gene variants. This study was approved by the Medical Ethics Committee of the Women's and Children's Hospital Affiliated to Xiamen University (Ethics No.: KY-2023-044-K02). RESULTS: The child was a 1-year-and-2-month-old male presenting with global developmental delay, encephalodysplasia, congenital heart disease and distinctive facial features. WES revealed that the child has harbored compound heterozygous variants of the TELO2 gene, namely c.1826G>A (p.Arg609His) and c.1514_1515delAG (p.Glu505Alafs21). Sanger sequencing confirmed that his mother carried a heterozygous c.1826G>A variant and his father carried a heterozygous c.1514_1515delAG variant. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were classified as likely pathogenic (PM2_Supproting+PM3_Strong+PP1+PP3; PVS1+PM2_Supproting). Literature review has identified 9 articles reporting 31 cases of YHFS due to TELO2 gene variants, with primary clinical manifestations including developmental delay, intellectual disability, distinctive facial features, and congenital heart disease. CONCLUSION The c.1826G>A (p.Arg609His) and c.1514_1515delAG (p.Glu505Alafs*21) compound heterozygous variants of the TELO2 gene probably underlay the pathogenesis of this child. Above finding has provided a basis for the clinical and genetic diagnosis of the child, which also enriched the mutational spectrum of the TELO2 gene, and improved understanding of YHFS.
Humans ; Male ; Infant ; Heterozygote ; Developmental Disabilities/genetics* ; Female ; Exome Sequencing ; Mutation ; Phenotype ; Abnormalities, Multiple/genetics* ; Child, Preschool

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

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 explore the genetic basis for a child featuring global developmental disorder with epilepsy. METHODS: A child who had presented at Guangzhou Women and Children's Medical Center in July 2022 was selected as the study subject. Clinical data was collected. Potential variant was detected by whole exome sequencing (WES). Candidate variant was validated by Sanger sequencing and bioinformatic analysis. RESULTS: The child, a three-year-old ethnic Zhuang Chinese girl, had presented with global developmental disorder and epilepsy, for which rehabilitation therapy was ineffective. Genetic testing revealed that she has harbored a homozygous c.821T>C (p.Leu274Pro) missense variant of the PIGW gene, for which both of her parents and sister were heterozygous carriers. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as variant of uncertain significance. CONCLUSION The homozygous c.821T>C (p.Leu274Pro) variant of the PIGW gene probably underlay the onset of disease in this child. Above finding has enriched the mutational spectrum of the PIGW gene.
Child, Preschool ; Female ; Humans ; Computational Biology ; Developmental Disabilities ; Epilepsy/genetics* ; Genetic Testing ; Homozygote

OBJECTIVE: To explore the clinical phenotype and genetic characteristics of a child with Intellectual developmental disorder with behavioral abnormalities and craniofacial malformations without epilepsy (IDDBCS). METHODS: A child who had visited the Lianyungang Maternal and Child Health Care Hospital in April 2021 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 and subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing of his family members. RESULTS: The child, a 3-year-and-4-month-old male, had presented with global developmental delay and cranial malformation. Genetic testing revealed that he has harbored a heterozygous c.1703delA (p.K568Sfs9) variant of the PHF21A gene, for which both of his parents were of the wild type. This low-frequency variant may alter the structure and function of the protein product. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), it was classified as a pathogenic variant (PVS1+PS2+PM2_Supporting). CONCLUSION The heterozygous c.1703delA (p.K568Sfs9) variant of the PHF21A gene probably underlay the IDDBCS in this patient.
Child ; Male ; Humans ; Infant ; Developmental Disabilities/genetics* ; Craniofacial Abnormalities/genetics* ; Seizures/genetics* ; Intellectual Disability/genetics* ; Problem Behavior ; Mutation

Objective: To discuss the clinical and genetic features of intellectual developmental disorder with behavioral abnormalities and craniofacial dysmorphism with or without seizures (IDDBCS). Methods: The clinical and genetic records of a patient who was diagnosed with IDDBCS caused by PHF21A gene variation at Children's Hospital Capital Institute of Pediatrics in 2021 were collected retrospectively. Using " PHF21A gene" as the keyword, relevant articles were searched at CNKI, Wanfang Data and PubMed from establishment of databases to February 2023. Clinical and genetic features of IDDBCS were summarized in the combination of this case. Results: An 8 months of age boy showed overgrowth (height, weight and head circumference were all higher than the 97^th percentile of children of the same age and sex) and language and motor developmental delay after birth, and gradually showed autism-like symptoms like stereotyped behavior and poor eye contact. At 8 months of age, he began to show epileptic seizures, which were in the form of a series of spastic seizures with no reaction to adrenocorticotropic hormone but a good response to vigabatrin. Physical examination showed special craniofacial appearances including a prominent high forehead, sparse eyebrows, broad nasal bridge, and downturned mouth with a tent-shaped upper lip. The patient also manifested hypotonia. Whole exome sequencing showed a de novo heterogeneous variant, PHF21A (NM_001101802.1): c.54+1G>A, and IDDBCS was diagnosed. A total of 6 articles (all English articles) were collected, involving this case and other 14 patients of IDDBCS caused by PHF21A gene variation. Clinical manifestations were intellectual disability or developmental delay (15 patients), craniofacial anomalies (15 patients), behavioral abnormalities (12 patients), seizures (9 patients), and overgrowth (8 patients). The main pathogenic variations were frameshift variations (8 patients). Conclusions: IDDBCS should be considered when patients show nervous developmental abnormalities, craniofacial anomalies, seizures and overgrowth. PHF21A gene variation detection helps to make a definite diagnosis.
Male ; Humans ; Child ; Intellectual Disability/genetics* ; Developmental Disabilities/genetics* ; Retrospective Studies ; Seizures/genetics* ; Craniofacial Abnormalities/genetics* ; Histone Deacetylases/genetics*

OBJECTIVE: To explore the clinical features and genetic etiology of two children with intellectual developmental disorder and microcephaly with pontine and cerebellar hypoplasia (MICPCH). METHODS: Two children with MICPCH who were presented at the Henan Provincial People's Hospital between April 2019 and December 2021 were selected as the study subjects. Clinical data of the two children were collected, along with peripheral venous blood samples of them and their parents, and amniotic fluid sample of the mother of child 1. Whole exome sequencing (WES), array-comparative genomic hybridization (aCGH) and real-time quantitative PCR (qPCR) were carried out for the children, their parents and the fetus. The pathogenicity of candidate variants were evaluated. RESULTS: Child 1 was a 6-year-old girl featuring motor and language delay, whilst child 2 was a 4.5-year-old girl mainly featuring microcephaly and mental retardation. WES revealed that child 2 has harbored a 158.7 kb duplication in Xp11.4 (chrX: 41446160_41604854), which has encompassed exons 4~14 of the CASK gene. The same duplication was not found in either of her parents. aCGH revealed that child 1 has harbored a 29 kb deletion at Xp11.4 (chrX: 41637892_41666665), which encompassed exon 3 of the CASK gene. The same deletion was not found in either of her parents and the fetus. The above results were confirmed by qPCR assay. Above deletion and duplication were not found in the ExAC, 1000 Genomes and gnomAD databases. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were rated as likely pathogenic (PS2+PM2_Supporting). CONCLUSION The deletion of exon 3 and duplication of exons 4~14 of the CASK gene probably underlay the pathogenesis of MICPCH in these two children, respectively.
Humans ; Child ; Female ; Child, Preschool ; Microcephaly/genetics* ; Developmental Disabilities/genetics* ; Intellectual Disability/complications* ; Comparative Genomic Hybridization ; Mutation