Xiaomei Lu

Background: Coffin-Siris syndrome type 2 (CSS2), caused by ARID1A mutations, is characterized by neurodevelopmental delay and recurrent infections. The ARID1A p.Ala1077Glu variant has been linked to CSS2, but the immune mechanisms underlying infection susceptibility remain poorly understood. Methods: The variant was identified by trio-based whole-exome sequencing and confirmed by Sanger sequencing. Immune status was assessed via serum immunoglobulins, complement measurements, and flow cytometric immunophenotyping. RNA sequencing was performed on PMA-stimulated PBMCs from the patient and healthy controls, with key findings validated by qRT-PCR and ELISA. Results: Immune profiling revealed widespread quantitative deficits across innate and adaptive compartments, with particularly marked reductions in NKT-like cells (CD3 ⁺ CD56 ⁺ ) and CD8 ⁺ central memory T cells. Transcriptomic analysis of stimulated cells uncovered a profound activation defect, characterized by widespread downregulation of effector immune genes. Furthermore, pathway enrichment analysis demonstrated significant suppression of multiple biological processes critically dependent on IFN-γ signaling, such as antigen processing and presentation, and Th1/Th17 cell differentiation. Expression of IFNG , STAT1 , and CXCL9 showed a trend toward decreased expression. Conclusion: Our findings suggest an association between the ARID1A p.Ala1077Glu variant and impaired IFN-γ-mediated immunity in CSS2, potentially contributing to recurrent infections. The IFN-γ pathway warrants further investigation as a therapeutic target.

Objective: Premature ovarian insufficiency (POI) with short stature and mild intellectual disability can have diverse genetic etiologies. We aimed to decipher the genetic basis of this complex phenotype in a 26-year-old female with a karyotype lacking aneuploidy. Design and Methods: This is a case study integrated with comprehensive genetic analyses. After standard techniques (karyotyping, CNV-seq, WES) failed to yield a diagnosis, Oxford Nanopore long-read sequencing was employed to map chromosomal breakpoints at single-base resolution. X-inactivation (XCI) analysis was also performed. Results: Long-read sequencing refined the karyotype to 46,X,t(X; 3;8) (q25; q21p21; p21),t(17; 22)(q21.2; q13) and identified direct disruptions of TAFA5, LARS2, and MYLK. XCI analysis demonstrated highly skewed XCI (5.35%), indicating preferential inactivation of the structurally normal X chromosome. Conclusion: We propose that highly skewed XCI is the primary driver of the patient’s POI and short stature, while the three disrupted genes may serve as modifying factors. This study underscores the value of long-read sequencing in resolving CCRs and the importance of XCI analysis in female patients with X-chromosome rearrangements.

NLRP3-associated autoinflammatory diseases (NLRP3-AIDs) are rare autoinflammatory disorders caused by uncontrolled inflammasome activation. While IL-1β blockade is first-line therapy, many patients respond inadequately, highlighting a need for alternative strategies. Transcriptomic analysis was performed on immune cells from a patient with an NLRP3 L573W mutation. Functional validation of CD177 as a downstream effector of NLRP3 activation was conducted. A novel NLRP3 L573W knock-in mouse model was established. Correlation between CD177 expression, disease severity, neutrophilia, and tissue damage was assessed. Therapeutic efficacy of siRNA-mediated CD177 silencing was evaluated and compared with IL-1β blockade. CD177, a neutrophil-specific protein, was significantly upregulated in NLRP3-mutant cells and confirmed as a direct downstream effector of NLRP3 activation. The NLRP3 L573W knock-in mouse recapitulated human disease heterogeneity, from mild self-limited inflammation to severe multi-organ pathology. CD177 expression correlated with disease severity, neutrophilia, and tissue damage. siRNA-mediated CD177 silencing attenuated systemic inflammation, reduced neutrophil infiltration and cytokine levels (IL-1β, IL-6, TNFα), and ameliorated multi-organ damage, with effects comparable to or exceeding those of IL-1β blockade. CD177 is a non-canonical amplifier of NLRP3-driven inflammation. Targeting CD177 represents a superior therapeutic strategy for NLRP3-AIDs, including IL-1β-refractory cases.

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is traditionally recognized as a risk factor for drug- or infection-induced hemolytic anemia. Emerging evidence implicates potential roles of G6PD in neurodevelopment, yet its association with rare neurological disorders remains underexplored in population-based genetic studies, especially within the Chinese population. Methods: We conducted a retrospective case-control study utilizing whole-exome sequencing (WES) data from a Chinese cohort. Six most prevalent pathogenic G6PD variants in China were screended in children with rare neurological disorders (n = 211) and in controls without neurological involvement (n = 202). Genotype and carrier frequency comparisons were performed. Stratified analyses were performed based on diagnostic certainty and the presence of de novo mutations. Multivariable logistic regression was employed to calculate sex-adjusted odds ratios (ORs) to control for potential sex-related confounding. Results: After adjusting for sex, the overall carrier rate of pathogenic G6PD variants was significantly higher in patients with neurological disorders than in controls (adjusted OR = 2.44, 95% CI: 1.18–5.06, p = 0.014). Further comparisons across specific groups revealed distinct patterns: affected male patients had a higher carrier rate than their own unaffected fathers (OR = 2.30, 95% CI: 1.08–4.91, p = 0.043), and mothers of case patients showed a higher carrier rate than mothers of controls (OR = 2.03, 95% CI: 1.09–3.78, p = 0.030). The variants NM_001042351.3: c.1376G>T (G6PD Canton) and NM_001042351.3:c.1388G>A (G6PD Kaiping) were the most prevalent across all groups. Conclusion: This population-based genetic analysis provides preliminary evidence that G6PD deficiency may be a underrecognized genetic risk factor for rare neurological disorders in Chinese children. The findings suggest a potential maternal genetic contribution and indicate that the phenotypic spectrum of G6PD deficiency may extend beyond hematological manifestations to include neurodevelopmental vulnerability. Important limitations include the lack of functional validation and the use of a clinical control group. Further prospective studies incorporating G6PD enzyme activity assessment and functional investigations are warranted to elucidate the underlying mechanisms.

Background: PU.1 deficiency, also known as Autosomal Dominant Agammaglobulinemia-10 (AGM10), is a rare primary immunodeficiency caused by mutations in the SPI1 gene, leading to B cell deficiency and hypogammaglobulinemia. To date, human cases of SPI1 -related immunodeficiency have been reported in only a limited number of publications, highlighting the scarcity of clinical data and the importance of further characterization. Case description: We describe a Chinese patient with recurrent respiratory infections, agammaglobulinemia, and profound B cell lymphopenia. Initial genetic screening using a targeted Primary Immunodeficiency Panel did not identify any related pathogenic variants. Subsequent whole-exome sequencing revealed a novel de novo nonsense mutation in the SPI1 gene(NM_003120.3:c.130G>T, p.Glu44Ter). The patient subsequently underwent hematopoietic stem cell transplantation (HSCT). Immunological recovery progressed favorably, with B-cell reconstitution and normalization of immunoglobulin levels occurring by approximately 10 months post-HSCT. However, the clinical course was complicated by severe viral meningoencephalitis occurring around two months post-HSCT, which presented as recurrent fever. Cerebrospinal fluid analysis confirmed infection with cytomegalovirus (CMV) and torque teno virus (TTV). This infection resulted in progressive neurological deterioration and permanent paralysis. Conclusion: We report the first Chinese case of PU.1 deficiency caused by a novel SPI1 mutation. Our finding reinforces the need to include SPI1 in diagnostic panels for agammaglobulinemia. Moreover, the severe viral meningoencephalitis after HSCT, despite immune reconstitution, underscores the critical need for aggressive peri-transplant surveillance.

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease characterized by absolute insulin (INS) deficiency. As key components of the immune system, macrophages play critical roles in T1DM-associated pancreatic β-cell damage and multiorgan inflammatory injuries. Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-EXOs) have emerged as promising therapeutic agents for immune-related disorders due to their immunomodulatory properties and favorable safety profile. However, systematic investigations into the therapeutic potential of hucMSC-EXOs in T1DM are lacking. This study aimed to evaluate the systemic anti-inflammatory effects of hucMSC-EXOs in T1DM and identify their key bioactive components. T1DM was induced in C57BL/6 male mice via streptozotocin, followed by intraperitoneal administration of hucMSC-EXOs. Systemic glucose metabolism, multiorgan pathology, and macrophage infiltration were assessed. In vitro, THP-1-derived macrophages were polarized to an M1 phenotype and treated with hucMSC-EXOs. Proteomic profiling, pharmacological inhibition, and functional assays were employed to identify critical exosomal components. hucMSC-EXOs significantly reduced hyperglycemia, restored glucose tolerance, and attenuated structural damage in the pancreas, spleen, liver, kidney, and heart of T1DM mice (p < 0.05). Mechanistically, hucMSC-EXOs suppressed macrophage infiltration and proinflammatory cytokine secretion (IL-6, TNF-α, CCL-2) across tissues. Proteomic analysis revealed INS and superoxide dismutase 1 (SOD1) as enriched anti-inflammatory proteins in hucMSC-EXOs. Heat inactivation abolished their bioactivity, while pharmacological inhibition of INS (S961) or SOD1 (ATN-224) reversed hucMSC-EXOs-mediated suppression of macrophage activation (p < 0.01). This study demonstrates that hucMSC-EXOs ameliorate T1DM- associated hyperglycemia and multiorgan inflammation by targeting macrophage polarization through delivery of INS and SOD1. Our study reveals that hucMSC-EXOs exert their anti-inflammatory effects through coordinated delivery of insulin and SOD1, establishing a protein-centric mechanism for exosome-mediated immunomodulation in T1DM.

Background: The AIFM1 gene is located on chromosome Xq26.1 and encodes a flavoprotein essential for nuclear disassembly in apoptotic cells. Mutations in this gene can cause variable clinical phenotypes, but genotype-phenotype correlations of AIFM1-related disorder have not yet been fully determined because of the clinical scarcity.Case Presentation: We describe a 4-month-old infant with mitochondrial encephalopathy, carrying a novel intronic variant in AIFM1 (NM_004208.4: c.1164 + 5G > A). TA cloning of the complementary DNA (cDNA) and Sanger sequencing revealed the simultaneous presence of an aberrant transcript with exon 11 skipping (89 bp) and a normal transcript through analysis of mRNA extracted from the patient’s fibroblasts, which is consistent with direct RNA sequencing results.Conclusion: We verified the pathogenic effect of the AIFM1 c.1164 + 5G > A splicing variant, which disturbed normal mRNA splicing. Our findings expand the mutation spectrum of AIFM1 and point out the necessity of intronic sequence analysis and the importance for integrative functional studies in the interpretation of sequence variants.

Aims: Van der Woude syndrome (VWS) is one of the most common craniofacial anomalies, causing significant functional and psychological burden to the patients. This study aimed to identify the genetic cause of VWS in a Chinese family. Methods: Whole genome sequencing (WGS) was performed to screen for pathogenic mutations. Various Bioinformatics tools were used to assess the pathogenicity of the variants. Cosegregation analysis of the candidate variant was carried out. Interpretation of variants was performed according to the American College of Medical Genetics and Genomics guidelines. Results: A novel frameshift duplication c.373_374dupAA (p.Asn125Lys fs*43) was identified in exon 4 of the interferon regulatory factor 6 (IRF6) gene in all 3 affected members, which were not found in unaffected family members. The novel mutation leads to a frameshift and a premature stop codon which caused putative truncated protein. Protein alignment indicated high evolutionary conservation of the p.N125 residue, and this mutation was predicted by online tools to be damaging and deleterious. Conclusions: This study demonstrates that the novel mutation c.373_374dupAA (p.Asn125Lysfs*43) in the IRF6 gene corresponds to the VWS in this family. The discovery of this pathogenic variant enriches the genotypic spectrum of IRF6 gene and contributes to genetic diagnosis and counseling of families with VWS.