Chunquan Cai

Background IgA nephropathy (IgAN) is the most common glomerulonephritis in children. Although exosomes contribute to renal injury, their role in IgAN remains unclear. This pilot study tested whether urinary exosomal C3a normalized to creatinine (uE-C3a/Cr) reflects glomerular injury and activates NF-κB signaling. Methods We enrolled 70 children with IgAN, 43 with other glomerulopathies, and 30 healthy controls. After isolating exosomes, we quantified uE-C3a/Cr and assessed correlations with clinical and pathological parameters. In parallel, IgAN model rats were examined for renal exosomal C3a (rE-C3a), NF-κB phosphorylation, and inflammatory cytokines. In vitro, rat mesangial cells were exposed to patient-derived IgAN exosomes, with or without a C3aR antagonist. Results uE-C3a/Cr was elevated in IgAN patients, correlating with log24 h-UP (ρ = 0.480, P < 0.001) and Oxford C score (ρ = 0.565, P < 0.001). The AUC for IgAN vs. non-IgAN was 0.637. In follow-up, uE-C3a/Cr decreased in remission patients; at 12 weeks, non-remission patients in the IST group had higher levels than remission patients (P < 0.001). In IgAN rats, rE-C3a was upregulated alongside an enhanced p-p65/t-p65 ratio and elevated MCP-1 and IL-6. Exosomes from IgAN patient urine promoted rat mesangial cell proliferation and enhanced NF-κB phosphorylation and cytokines; these effects were partially reversed by C3aR antagonist. Conclusions uE-C3a/Cr is not a disease-specific diagnostic marker for IgAN, but may serve as a non-invasive marker for monitoring disease activity and treatment response. Exosomal C3a appears to activate mesangial NF-κB through C3a/C3aR, pointing to C3aR as a therapeutic target in IgAN. Larger cohorts must validate these findings. Graphical abstract This study integrates clinical, in vivo, and in vitro evidence. Urinary exosomal C3a appears to reflect renal injury in pediatric IgAN and may activate mesangial NF-κB via C3a/C3aR.

Background: Type 1 diabetes mellitus (T1DM) is a chronic disease that significantly impacts patients’ quality of life. Its prevalence is rising globally each year. This study aims to identify potential biomarkers associated with T1DM through comprehensive bioinformatics analysis, further enhancing T1DM early diagnosis and treatment. Methods: Transcriptome datasets from T1DM patients and the control group were from the Gene Expression Omnibus (GEO) database. Differentially Expressed Genes (DEGs) were identified and subsequently analyzed using Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and protein–protein interaction (PPI) network analysis. Hub genes were identified using Enzyme-Linked Immunosorbent Assay (ELISA) on clinical samples comprising 17 T1DM patients and 19 controls. Immune cell infiltration was estimated using the Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) algorithm, while the diagnostic performance of the hub genes was evaluated via receiver operating characteristic (ROC) curve analysis. Results: A total of 20 up-regulated and eight down-regulated DEGs were identified in the GEO database. Functional enrichment analysis showed that immune activation played an important role in T1DM. The expression levels of the hub genes, CTSG and LTF , were further validated in clinical samples. ROC analysis showed moderate diagnostic performance, with AUC values of 0.75 (training set) and 0.67 (validation set). Conclusions: The results indicate that CTSG and LTF may serve as promising diagnostic biomarkers for T1DM. Our study is positioned as exploratory with moderate diagnostic relevance rather than definitive biomarker discovery. The findings are preliminary and require further validation before any clinical application.

Neurodevelopmental disorders (NDDs) are a group of developmental brain disorders caused by various genetic or acquired factors. OMIM has only recently associated the KCNK3 gene with developmental delay associated with sleep apnea (DDSA). Most prior studies on the KCNK3 gene have focused on PAH and cardiovascular diseases. In a 2‐year‐old girl presenting with generalized hypotonia and delayed language development, we identified a de novo missense variant in KCNK3 through the reanalysis of trio‐whole exome sequencing (trio‐WES) data. To further explore the relationship between KCNK3 and neurodevelopmental phenotypes, we conducted bidirectional expression regulation of the homologous gene Task7 based on the Drosophila model. Both overexpression and knockdown of the Task7 gene induced anxiety‐like behaviors and impaired learning and memory. Notably, Task7 overexpression also led to reduced climbing ability and abnormal sleep patterns; collectively, these four phenotypes recapitulate the characteristic hallmarks of human neurodevelopmental disorders. This study represents the first application of a Drosophila model to demonstrate that KCNK3 functions as a dosage‐sensitive regulator of neurodevelopment. While the underlying mechanisms remain to be fully elucidated, these findings position KCNK3 as a candidate gene for molecular screening and pave the way for future functional studies and therapeutic exploration in NDDs.

Purpose: Diagnosing pulmonary tuberculosis (PTB) in children remains challenging due to its often non-specific clinical presentation. Early detection enables timely treatment initiation. This study aimed to develop and validate a predictive model to distinguish PTB from Streptococcus pneumoniae pneumonia (SPP) in children. Methods: Lung CT images were obtained from 52 children with PTB and 80 with SPP, from which 1,023 radiomic features were extracted. The data were randomly split into training and test sets at a 7:3 ratio. Variance threshold, univariate analysis, and LASSO regression were applied sequentially to select the key radiomic features. Subsequently, an XGBoost model integrating clinical factors and radiomic features was constructed. The SHAP method was used to interpret the model and its decision process. Results: After feature selection, six radiomic features and three clinical features were retained for model construction. The combined radiomic-clinical model outperformed both the clinical-only and radiomic-only models. Its AUC was 0.981 in the training cohort and 0.897 in the test cohort. The clinical model achieved AUCs of 0.955 and 0.784, and the radiomic model achieved 0.868 and 0.865, respectively. SHAP summary and waterfall plots illustrated the contribution of each feature to the predictions. Conclusion: The SHAP-XGBoost radiomic-clinical model accurately distinguished PTB from SPP in children. It may offer a non-invasive and efficient tool to support clinical decision-making.

Background: Succinic semialdehyde dehydrogenase deficiency (SSADHD), caused by variants in ALDH5A1 , is a rare inherited neurometabolic disorder with phenotypic heterogeneity. To clarify the pathogenicity of ALDH5A1 variants, we systematically investigated their effects on succinic semialdehyde dehydrogenase (SSADH) structure and function. Methods: We obtained the clinical and molecular characteristics of 12 probands. We further augmented the pathogenicity dataset for 14 variants using multiple in silico tools under the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guideline. More importantly, we provided quantitative data on protein expression and residual enzyme activity for SSADH, enabling robust assignment of ACMG PS3/BS3 codes. Finally, we integrated 3D structural modelling with changes in physicochemical properties to butter elucidate how individual variants impair SSADH function. Results: Patients with SSADHD exhibit varying degrees of epilepsy, intellectual disorders, developmental delay, and hypotonia. Among the 14 variants, 9 affect SSADH expression level of protein, and 9 affect SSADH enzyme activity. After acquiring functional experiments’ results, PS3 was assigned to 10 variants and BS3 to 1; more notably, 8 variants obtained more plentiful pathogenic evidence. Intriguingly, we also investigated the underlying mechanisms using protein-based prediction techniques, 2 of 14 variants influenced binding of SSADH to small molecules, whereas 3 of 14 variants led to instability. Besides, as the SSADH with variants in the oligomerization domain accumulates in the tetramer, the tetramer becomes increasingly unstable. Conclusion: In this study, we illustrated that 14 ALDH5A1 variants affected the molecular structure and function by diverse mechanisms, and with varying degrees, which could help us to gain a deeper understanding of these variants by providing reasonable evidence based on the PS3/BS3 codes in the ACMG guidelines. Essentially, this pathogenic classification facilitates the diagnosis of SSADHD in future genetic testing processes.

Background: Pathogenic POR variants cause P450 oxidoreductase deficiency, a rare steroidogenesis disorder. Missense changes are well characterized, but the clinical and molecular consequences of splicing defects remain unclear. Methods: We identified a novel homozygous splice variant (c.1249-2A>C) in a patient with disorders of sex development and Antley-Bixler syndrome -like skeletal malformations. By reviewing 12 published cases and performing minigene assays on five variants (c.731 + 1G>A, c.732-2A>T, c.947 + 1G>A, c.948-30G>A, c.1249-2A>C), we characterized their splicing outcomes. Structural consequences were predicted using AlphaFold; nonsense-mediated mRNA degradation was assessed for c.1249-2A>C using cycloheximide block. Results: c.731 + 1G>A and c.947 + 1G>A caused intron retention with premature termination, deleting FAD/NADPH-binding domains. c.732-2A>T and c.1249-2A>C skipped exons 8 and 12, which altered FAD-binding site conformation. c.1249-2A>C mRNA reduction was not rescued by cycloheximide, arguing against NMD and suggesting nuclear retention or intranuclear decay. We classified two variants as pathogenic (c.731 + 1G>A, c.947 + 1G>A), two as likely pathogenic (c.732-2A>T and the novel c.1249-2A>C), and one as likely benign (c.948-30G>A). Conclusion: Our findings establish that POR splicing variants, whether causing exon skipping or intron retention, disrupt essential domains and produce severe disease. Minigene-based functional testing enables precise variant classification and sharpens genotype-phenotype correlations, supporting improved diagnosis and informed genetic counseling.

Background: Autism Spectrum Disorder (ASD) is frequently accompanied by gastrointestinal (GI) comorbidities and gut microbiota dysbiosis. While the microbiota-gut-brain axis is implicated in ASD pathophysiology, the upstream host genetic factors that drive these specific microbial alterations remain poorly characterized. Methods: To bridge this gap, we performed an integrated multi-omics analysis combining whole-exome sequencing, 16S rRNA gene sequencing, and plasma metabolomics in a cohort of children with ASD and typically developing controls. Results: We confirmed that children with ASD exhibit significant gut microbial dysbiosis and metabolic perturbations, which correlated with GI symptom severity. Crucially, rare variant enrichment analysis identified a significant accumulation of deleterious variants in mucin biosynthesis pathways (specifically the MUC gene family), which are essential for intestinal mucus barrier integrity. Multi-omics integration revealed that these host genetic defects were associated with distinct shifts in the gut ecosystem, notably the depletion of beneficial butyrate-producing bacteria (e.g., Faecalibacterium) and the expansion of mucin-degrading taxa. This structural dysbiosis translated into functional metabolic impairments, particularly in lipid transport and short-chain fatty acid metabolism, which tracked with ASD severity. Conclusion: Collectively, our data argue for a host-centric cascade where genetic vulnerabilities-specifically within the MUC pathway-compromise mucosal integrity, acting as a selective filter that fundamentally reshapes the gut microbiome. By pinpointing these variants as upstream drivers of gut-brain axis dysfunction, we move beyond simple association to identify concrete genetic targets-rare deleterious variants in the mucin (MUC) gene family-for future precision interventions in ASD.

Introduction/Aims: Previous studies of children with spinal muscular atrophy (SMA) have focused on the ulnar and median nerves, while lower‐limb and proximal motor nerves remain insufficiently characterized. This study aimed to evaluate compound muscle action potential (CMAP) amplitudes in upper‐ and lower‐limb motor nerves in children with SMA and changes after nusinersen treatment. Methods: In this single‐center retrospective study, CMAP amplitudes were collected from children with SMA and age‐matched controls without neuromuscular disease. CMAP amplitudes of the tibial, peroneal, femoral, median, and ulnar nerves were assessed in children with SMA types 1–3. A cross‐sectional analysis was conducted to assess CMAP amplitudes prior to treatment. Longitudinal changes after SMA disease‐modifying therapies (nusinersen monotherapy or nusinersen plus risdiplam treatment) were evaluated. Results: A total of 47 children with SMA were included. The baseline CMAP amplitudes of the peroneal, tibial, median, and ulnar nerves were the highest in type 3, followed by type 2, and lowest in type 1. Femoral nerve CMAP amplitudes were low in all SMA subtypes. At preliminary diagnosis, children with SMA had significantly reduced CMAP amplitudes for the five nerves compared with age‐matched controls ( n = 63, p < 0.05). After 18 months of nusinersen treatment, CMAP amplitudes showed significant increases from baseline in the peroneal, femoral, median, and ulnar nerves ( p < 0.05). Discussion: CMAP amplitudes can differentiate SMA disease severity and may increase after nusinersen treatment. Large‐scale longitudinal studies are required to investigate CMAP amplitude as a biomarker of treatment response in patients with SMA .