The KCNQ potassium channels play a crucial role in modulating neural excitability, and their dysfunction is closely associated with epileptic disorders. While variants in KCNQ2 have been extensively studied, KCNQ3-related disorders have rarely been reported. With advances in next-generation sequencing technologies, an increasing number of cases of KCNQ3-related disorders have been identified. However, the correlation between genotype and phenotype remains poorly understood. In this study, we established a variant library consisting of 24 missense mutations in KCNQ3 and introduced these mutations into three different template types: KCNQ3, KCNQ3-A315T (Q3*), and KCNQ3-KCNQ2 tandem (Q3-Q2). We then analyzed the effects of these mutations on the KCNQ3 channel function using patch-clamp recording. The most informative parameter across all three backgrounds was the current density of the mutant channels. The current density patterns in the Q3* and Q3-Q2 backgrounds were similar, with most mutations resulting in an almost complete loss of function (LOF), they were concentrated in the pore-forming domain of KCNQ3. In contrast, mutations in the voltage-sensing domain or C-terminus did not show significant differences from the wild-type channel. Interestingly, these LOF mutations were typically associated with self-limited familial neonatal epilepsy, while neurodevelopmental disorders (NDD) were more closely associated with mutations that did not significantly differ from the wild-type. V_1/2, another important parameter of the electrophysiological properties, could not be accurately determined in the majority of KCNQ3 mutations due to its nearly complete LOF in the Q3* and Q3-Q2 backgrounds. Intriguingly, the V_1/2 of functional mutations were primarily leftward shifted, indicating a gain-of-function (GOF) effect, which was typically associated with NDD. In addition to previously reported mutations, we identified G553R as a novel GOF mutation. In the co-transfection background, parameters such as V_1/2 could be determined, but the dysfunctional effects of these mutations were mitigated by the co-expression of wild-type KCNQ3 and KCNQ2 subunits, resulting in no significant differences between most mutations and the wild-type channel. Furthermore, we applied KCNQ modulators to reverse the electrophysiological abnormalities caused by KCNQ3 variants. The LOF mutations were reversed by the application of Pynegabine (HN37), a KCNQ opener, while the GOF mutation responded well to Amitriptyline (AMI), a KCNQ inhibitor. These findings provide essential insights into the pathogenic mechanisms underlying KCNQ3-related disorders and may inform clinical decision-making.
KCNQ3 Potassium Channel/genetics* ; Humans ; Mutation, Missense/genetics* ; KCNQ2 Potassium Channel/genetics* ; Patch-Clamp Techniques ; HEK293 Cells ; Animals ; Phenylenediamines/pharmacology* ; Carbamates

Muenke syndrome is an autosomal dominant genetic disorder that is typically characterized by unilateral or bilateral coronal synostosis, macrocephaly, midface hypoplasia, and developmental delays. This article reports a case of Muenke syndrome with a soft cleft palate. A heterozygous missense mutation c.749C>G (p.P250A) was identified in the FGFR3 gene through genetic testing. The patient exhibited typical features including coronal synostosis, bilateral hearing loss, right accessory auricle, and developmental delays and underwent surgery to repair the soft cleft palate. Cases of Muenke syndrome with cleft palate in the literature are relatively rare, and common associated symptoms include coronal suture craniosynostosis and hearing impairment. This article reports a differential diagnosis with other craniosynostosis syndromes and provides a reference for clinical diagnosis and treatment.
Humans ; Cleft Palate/surgery* ; Craniosynostoses/diagnosis* ; Mutation, Missense ; Palate, Soft/abnormalities* ; Receptor, Fibroblast Growth Factor, Type 3/genetics*

Collagen, a vital matrix protein for various tissue and functions in animals, is widely applied in biomaterials. In type Ⅰ collagen, missense mutations of glycine (Gly) in the Gly-Xaa-Yaa triplet of the triple helix are a major cause of osteogenesis imperfecta (OI). Clinical manifestations exhibit marked heterogeneity, spanning a broad disease spectrum from mild skeletal fragility (Type Ⅰ) to severe limb deformities (Type Ⅲ) and perinatal lethal forms (Type Ⅱ). This study utilized recombinant collagen as a model to further elucidate whether Gly→Ala/Val mutations at the N-terminus of the integrin-binding sequence GFPGER affect collagen structure and function, and to explore the underlying mechanisms by which missense mutations impact the biological function of collagen. By introducing Ala and Val substitutions at seven Gly positions N-terminal to the GFPGER sequence, we systematically assessed the effects of these amino acid replacements on the triple-helical structure, thermal stability, integrin-binding ability, and cell adhesion of recombinant collagen. All constructs formed a stable triple-helix structure, with slightly compromised thermal stability. Gly→Val substitutions increased the susceptibility of recombinant collagen to trypsin, which suggested local conformational perturbations in the triple helix. In addition, Gly→Val substitutions significantly reduced the integrin-binding affinity and decreased HT1080 cell adhesion, with the effects stronger than Gly→Ala substitutions. Compared with Gly→Ala substitutions, substitution of Gly with the larger residue Val had enhanced negative effects on the structure and function of recombinant collagen. These findings provide new insights into the molecular mechanisms of osteogenesis imperfecta and offer theoretical references and experimental foundations for the design of collagen sequences and the development of collagen-based biomaterials.
Recombinant Proteins/biosynthesis* ; Glycine/genetics* ; Humans ; Osteogenesis Imperfecta/genetics* ; Integrins/metabolism* ; Collagen/metabolism* ; Collagen Type I/metabolism* ; Amino Acid Substitution ; Mutation ; Mutation, Missense

OBJECTIVE: To explore the genotype-phenotype correlation in a Charcot-Marie-Tooth type 2A2A (CMT2A2A) pedigree and to provide genetic counseling for its subsequent pregnancies. METHODS: A Chinese pedigree presenting with "lower limb muscle atrophy and movement disorders" at the Prenatal Diagnosis Center of Xuzhou Central Hospital between January and August 2024 was selected as the study subject. Relevant clinical data were collected from the pedigree members. Peripheral blood samples from affected individuals, and amniotic fluid and/or chorionic villus samples were obtained for DNA extraction. Whole exome sequencing (WES) was carried out. Candidate variants were verified by Sanger sequencing. Pathogenicity assessment and bioinformatic analysis were conducted. This study was approved by the Medical Ethics Committee of Xuzhou Central Hospital (Ethics No. XZXY-LK-20240111-0019). RESULTS: All affected individuals in this pedigree were females, whom included the proband, her mother, and her first daughter. Earlier age of onset was associated with more severe lower limb atrophy. A heterozygous missense variant of the MFN2 gene, namely c.314C>T (p.Thr105Met), was identified in the proband, her mother, daughter, and the third fetus from a re-marriage. The same variant was absent in her elder brother, current husband, and her fourth fetus. Based on the guidelines from American College of Medical Genetics and Genomics (ACMG) and recommendations from Clinical Genome Resources (ClinGen), the variant was classified as pathogenic (PP1_Strong+PM1+PS3+PS4_Moderate+PP3_Moderate+PM2_Supporting). Analyses with PROVEAN and Mutation Taster had categorized the variant as "deleterious" and "disease-causing", respectively. Analysis with Uniprot and Jalview showed that the affected amino acid residue is conserved across multiple species. ChEBI software predicted that the variant may alter the polarity of the 105th amino acid residue. CONCLUSION The c.314C>T (p.Thr105Met) missense variant of the MFN2 gene probably underlie the CMT2A2A in this pedigree. Above finding has enabled prenatal diagnosis and genetic counseling for its subsequent pregnancies.
Adult ; Female ; Humans ; Male ; Charcot-Marie-Tooth Disease/genetics* ; East Asian People/genetics* ; Exome Sequencing ; Genetic Testing/methods* ; GTP Phosphohydrolases/genetics* ; Mitochondrial Proteins/genetics* ; Mutation, Missense ; Pedigree

OBJECTIVE: To explore the clinical phenotype and genetic characteristics of a Chinese Han pedigree with Darier's disease (DD). METHODS: A DD pedigree, who visited Tongji Hospital of Tongji University on October 22, 2023, was selected as the study subject. Clinical data of the pedigree were collected, and whole exome sequencing was performed on the proband. Suspected variant loci were screened, and Sanger sequencing was used to validate the variant in pedigree members. Bioinformatics analysis was performed on the variant loci. This study was approved by the Medical Ethics Committee of Tongji Hospital of Tongji University Ethics No.K-W-2024-004). RESULTS: The proband is a 67-year-old female with clinical features of DD, such as keratotic papules in sebaceous areas. whole exome sequencing revealed a missense variant, c.68G>A (p.Gly23Glu), in the exon 1 of ATP2A2 gene of the proband. Sanger sequencing showed that the proband's eldest daughter also carried this variant. This variant was not detected in other pedigree members, indicating a co-segregation of the variant with the disease phenotype in the pedigree. According to the interpretation principles of gene variants by the American College of Medical Genetics and Genomics (ACMG), this variant was classified as pathogenic (PS1+PM1+PM2_Supporting+PP1+PP3+PP4). CONCLUSION The c.68G>A (p.Gly23Glu) variant in the ATP2A2 gene may be the genetic cause of the disease in this pedigree. This finding further enriches the genetic variant spectrum in DD patients and provides a basis for clinical diagnosis and genetic counseling for patients.
Aged ; Female ; Humans ; Male ; China ; Darier Disease/genetics* ; Exome Sequencing ; Mutation, Missense ; Pedigree ; Phenotype ; East Asian People ; Sarcoplasmic Reticulum Calcium-Transporting ATPases

OBJECTIVE: To explore the genetic basis of a patient with suspected Oculocutaneous albinism (OCA). METHODS: An OCA patient presented at the West China Second Hospital of Sichuan University and his mother were selected as the study subjects. Peripheral blood samples were collected for the extraction of, genomic DNA, and whole exome sequencing (WES) was carried out. Candidate variants were verified through specific primer amplification, Sanger sequencing, and agarose gel electrophoresis. Bioinformatic analysis and pathogenicity rating were conducted on the candidate variants. This study has been approved by the Medical Ethics Committee of West China Second Hospital (No. 2024-228). RESULTS: Genetic testing revealed that the patient had harbored variants in exon 1 of the TYR gene, including a c.157G>T (p.G53C) missense variant and a c.609dup (p.A204fs) frameshifting variant. Specific primer amplification and Sanger sequencing, combined with agarose gel electrophoresis, confirmed that these are compound heterozygous variants. Based on the guidelines from the ACMG, the c.157G>T was rated as likely pathogenic, and c.609dup was rated as pathogenic. Alphafold3 predicted that the variant proteins had significant structural changes. CONCLUSION The patient was diagnosed with OCA due to compound heterozygous variants of the TYR gene. Discovery of the c.609dup variant has enriched the mutational spectrum of OCA and provided a basis for genetic counseling and prenatal diagnosis for this patient.
Humans ; Albinism, Oculocutaneous/enzymology* ; Male ; Female ; Monophenol Monooxygenase/chemistry* ; Base Sequence ; Mutation, Missense

OBJECTIVE: To investigate the genetic etiology of six adult patients with Dilated cardiomyopathy (DCM), and analyze the structure of the identified variants, for providing reference for the diagnosis of DCM. METHODS: Six adult patients with DCM (patients 1-6) admitted to the Department of Cardiology of Zhumadian Central Hospital from January 2023 to December 2023 were recruited. Clinical data of the patients were retrospectively collected. And 5 mL of peripheral blood was collected from each patient. Pathogenic variants of the patients were detected by whole exome sequencing (WES), and candidate variants were verified by Sanger sequencing. The possible functional significance of the identified missense variants was evaluated using software including SIFT, PolyPhen-2 and Mutation Taster. Specific regions of the MYBPC protein encoded by the MYBPC3 gene from different species were aligned using Mutation Taster. The wild-type and mutant MYBPC proteins were constructed using homologous modeling software MODELLER v10.4 and three-dimensional structures were visualized using PyMOL software. The molecular interaction between MYBPC-C5 domain and myosin with or without the mutation was further analyzed using ZDOCK module in Discovery Studio 2019 software. Pathogenicity ratings for the detected variant sites were performed in accordance with the Standards and Guidelines for the Interpretation of Sequence variants by the American College of Medical Genetics and Genomics (ACMG) (hereafter referred to as the ACMG Guidelines). This study was reviewed and approved by the Ethics Committee of Zhumadian Central Hospital (Approval No. 2022092007). RESULTS: The six DCM patients had typical symptoms of heart failure, and echocardiography showed whole-heart dilation and decreased ventricular wall motion, left ventricular end-diastolic dimension (LVEDD) was 59-74 mm, left ventricular ejection fraction (LVEF) was 35%-43%, and left ventricular fractional shortening (LVFS) was 17%-28%. Variations of the DCM related genes, including a c.98473A>T (p.Lys32825*) variation of the TTN gene and a c.1976T>C (p.Ile659Thr) variation of the MYBPC3 gene, were identified in two patients. Multiple software predicted that both mutations were deleterious. MYBPC3-Ile659Thr mutation affected the highly conserved residue within the C5 domain of MYBPC. Three-dimensional structural analysis of homologous modeling revealed the alterations in amino acid properties and interactions with surrounding amino acids caused by the MYBPC3-Ile659Thr mutation. Further molecular docking analysis showed that the Ile659Thr mutation altered both the hydrogen bond and salt-bridge interactions between the MYBPC-C5 domain and the ligand myosin. CONCLUSION Two mutations associated with DCM were identified in this study. The abnormal conformation of the mutant protein further affected its interaction with the ligand myosin, resulting in the phenotype of DCM.
Humans ; Cardiomyopathy, Dilated/genetics* ; Male ; Adult ; Female ; Carrier Proteins/chemistry* ; Middle Aged ; Mutation ; Exome Sequencing ; Mutation, Missense ; Retrospective Studies ; Myosin Binding Protein C

OBJECTIVE: To explore the genetic etiology of a child with Brain small vessel disease 1 with ocular anomalies. METHODS: A child who was admitted to Ningbo Women and Children's Hospital on May 28, 2022 was selected for the study. Clinical data were collected, and peripheral blood samples from the child and her parents were obtained for genomic DNA extraction. Whole exome sequencing (WES) was performed to screen for pathogenic variants. Candidate variants were validated via Sanger sequencing and subjected to bioinformatic analysis. This study was approved by the Medical Ethics Committee of Ningbo Women and Children's Hospital (Ethics No. EC2020-014). RESULTS: The child was a 7-year-old female with a diagnosis of epilepsy. WES revealed that she has carried a heterozygous missense variant in the COL4A1 gene: c.1792G>A (p.Gly598Ser). Sanger sequencing confirmed that her parents both had the wild-type genotype for this variant. Based on American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants, the variant were predicted to be a likely pathogenic (PS2+PM1+PM2_Supporting+PP3). Bioinformatics predicted that amino acid 598 was highly conserved in different species, formed hydrogen bond with Asp599 after becoming Ser598. CONCLUSION The heterozygous missense variant of the COL4A1 gene c.1792T>C (p.G598S) could be the pathogenic cause of this child with Brain small vessel disease 1 with ocular anomalies.
Humans ; Female ; Child ; Collagen Type IV/genetics* ; Eye Abnormalities/genetics* ; Exome Sequencing ; Mutation, Missense ; Cerebral Small Vessel Diseases/genetics*

OBJECTIVE: To explore the genetic basis for a woman with oocyte maturation disorder during assisted reproductive treatment (ART), and to verify the source of the variant and its impact on oocyte maturation through family verification. METHODS: A 35-year-old infertile woman presented at the Reproductive Medicine Center of Gansu Provincial Maternal and Child Health Care Hospital on 20 October 2023 for a 10-year history of infertility despite unprotected intercourse was selected as study subject. Peripheral venous blood sample was collected from the proband. Next-generation sequencing (NGS) was used to detect the potential variant. Candidate variants were validated within her family by Sanger sequencing, and their deleteriousness was assessed with comprehensive bioinformatic analyses to elucidate their origin and impact on oocyte maturation. According to the Standards and Guidelines for the Interpretation of Sequence Variants (hereinafter referred to as ACMG Guidelines) formulated by the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of the candidate variant was rated. This study was approved by the Medical Ethics Committee of Gansu Provincial Maternal and Child Health Care Hospital (Ethics No.: 2023GSFYLS78). RESULTS: The proband underwent three controlled ovarian-stimulation cycles as part of assisted reproductive technology, yielding a total of 29 oocytes, among which only three were mature, whilst the remainders exhibited maturation arrest. Targeted sequencing of peripheral-blood DNA revealed a heterozygous c.728C>T (p.P243L) missense variant of the TUBB8 gene. While the same variant was detected in the proband's father. Based on the ACMG guidelines, the variant was classified to be likely pathogenic (PS4_Supporting+PM2_Supporting+PP2+PP3+PP4). CONCLUSION The heterozygous c.728C>T (p.P243L) missense variant of the TUBB8 gene probably underlay the oocyte maturation disorder in the proband, which may be either autosomal dominant or autosomal recessive. For probands with oocyte maturation disorders caused by the heterozygous c.728C>T variant of the TUBB8 gene, oocyte donation may be considered.
Humans ; Female ; Adult ; Mutation, Missense ; Oocytes/metabolism* ; Heterozygote ; Tubulin/genetics* ; Infertility, Female/genetics* ; High-Throughput Nucleotide Sequencing ; Pedigree

OBJECTIVE: To analyze the clinical phenotype and genetic basis of four children with CHARGE syndrome. METHODS: A retrospective analysis was conducted on four children diagnosed with CHARGE syndrome at Xiamen Children's Hospital from May 2019 to May 2025. Peripheral venous blood samples were collected from the children and their parents and subjected to trio-whole exome sequencing. Candidate variants were verified by Sanger sequencing. Online tools were used for the conservation analysis and protein structure prediction. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No.: 2024-126). RESULTS: The four children have included two neonates, one infant and one child, with their age at the initial diagnosis ranging from 16 days after birth to 11 years old. Their initial manifestations were not typical of CHARGE syndrome. All children were found to harbor missense variants of the CHD7 gene, including c.3059T>C (p.L1020S), c.3302G>A (p.C1101Y), c.5879C>T (p.S1960F) and c.8093C>T (p.S2698L). Sanger sequencing confirmed that two were de novo variants, and two were inherited from their parents. In child 1, the leucine at position 1020 was highly conserved, and the p.L1020S variant did not alter the spatial structure and hydrogen bond connections of the CHD7 protein, though the shape of the binding cavity and the number and distribution of binding probe clusters have changed. In child 4, an unreported variant in the epilepsy gene SCN9A (c.2152T>C, p.Y718H) was detected, along with bilateral lower limb deformities. Literature review suggested that missense variants of the CHD7 gene were most common (32.1%) among the Chinese population, whilst nonsense variants had the highest lethality rate (41.2%) in neonates. CONCLUSION Variants of the CHD7 gene probably underlay the pathogenesis in the four children. Changes in the binding sites and binding cavity morphology play an important role in CHARGE syndrome. The types of genetic variants in CHARGE patients may vary between different regions and races.
Humans ; CHARGE Syndrome/genetics* ; Male ; Female ; Child ; Infant ; Infant, Newborn ; DNA Helicases/genetics* ; DNA-Binding Proteins/chemistry* ; Mutation, Missense ; Retrospective Studies ; Child, Preschool ; Exome Sequencing ; Phenotype