Biomedical subjects

Phan Q Duy

Publications and source records attributed to Phan Q Duy.

7 recordsLinked to original sources

PubMed2026

Microglial GRB2 is essential for brain ventriculogenesis and CSF homeostasis.

Microglia play essential yet poorly understood roles in brain development, including axon guidance, regulation of neurogenesis, and pruning of neuronal projections. Congenital hydrocephalus (CH), characterized by enlarged cerebrospinal fluid (CSF)-filled ventricles, is a leading cause of pediatric brain surgery, but its molecular mechanisms remain unclear. We have identified what we believe to be novel, recurrent, damaging missense variants in the SH3-binding domain of the adaptor protein Growth Factor Receptor-Bound Protein 2 (GRB2) in unrelated patients with CH. GRB2 is significantly co-expressed with one of its known upstream receptor tyrosine kinase partners, CSF1R, in the developing human brain, particularly in a microglial subtype associated with regulation of neural stem cells. Immunoprecipitation validated GRB2-CSF1R binding in mouse microglial cells and human monocyte cell line. Cx3cr1-Grb2fl/fl mice engineered with conditional deletion of Grb2 in microglia exhibit congenital absence of microglia and early postnatal severe communicating (non-obstructive) hydrocephalus, mimicking GRB2-mutant patients. The severe ventriculomegaly of Cx3cr1-Grb2fl/fl mice is associated with both depletion of cerebral cortical neurons and impairment of glia-lymphatic-mediated CSF flow. Together, these findings implicate a role of GRB2 in microglia that could be essential for brain development and CSF homeostasis.

Genetics↗

PubMed2026

Mechanistic insights into Claudin-14 dysfunction implicated in veins of Galen malformation.

Claudin-14 (CLDN14) is a key component of tight junctions (TJs) critical for maintaining paracellular barrier function. Variants of CLDN14 have been linked to Vein of Galen malformations (VOGMs), a rare cerebrovascular disorder; however, the molecular mechanisms underlying their pathogenicity remain unknown. Here, we investigate the mechanistic effects of two VOGM-associated mutations, A113P and V143M, using reinforcement-learning driven enhanced sampling molecular dynamics simulations combined with DiffNets-based deep learning and independent trajectory-wide structural analyses. Our analysis reveals that A113P induces broader structural disruption of CLDN14, perturbing paracellular sealing, pore symmetry, and inter-protomer communication, whereas V143M induces structural rearrangements centred around TM3 and the TM3-ECL2 region. In both cases, mutation-specific alterations are observed in structural stability and interfacial organization across oligomeric assemblies. Notably, these effects are qualitatively consistent across different modelled architectures, despite variability in local responses. In the absence of experimentally resolved structures, the structural perturbations reported here provide a mechanistic understanding of how VOGM-associated variants may influence CLDN14 structure and dynamics.

Aneurysm↗

PubMed2026

Developmental genetic determinants of the human cerebrospinal fluid-ventricular system.

Primary enlargement of the cerebrospinal fluid (CSF)-filled brain ventricles, known as congenital cerebral ventriculomegaly (CCV), is a hallmark of congenital hydrocephalus. CCV is also enigmatically but frequently associated with autism and other neurodevelopmental disorders. To gain insight into the developmental genetic regulation of the human CSF-ventricular system, we conducted an integrated, multiomic study of about 2700 trio-based exomes from patients with primary CCV. We found that about 25% of cases were associated with rare, damaging de novo variants in mutation-intolerant genes, many of which are linked to other dominant Mendelian disorders. Thirty-five exome-wide significant CCV genes and dozens of other high-confidence CCV genes converged on pathways involved in ATP-dependent Brahma-related gene 1/Brahma-associated factor chromatin remodeling, histone H3 lysine 4 methylation, and phosphoinositide 3-kinase signaling. Knockout of selected CCV genes in mouse models supported that de novo variants in CCV genes caused ventriculomegaly by impairing both CSF dynamics and cortical cytoarchitecture through dysregulation of neuroprogenitor cell growth and maturation in the ventricular and subventricular zones. These findings indicated that genetic and epigenetic programs coordinate the "hand-in-glove" development of the CSF-ventricular system with that of the cerebral cortex and establish a genetic connection between CCV and neurodevelopmental disorders, potentially explaining why some patients with hydrocephalus continue to exhibit CCV and neurodevelopmental disorders despite CSF shunting. We suggest that combined brain imaging and whole-exome sequencing could enable early detection of, and intervention for, autism and other neurodevelopmental disorders.

Humans↗

PubMed2026

Towards precision medicine for brain arteriovenous malformations.

Recent advances in cerebrovascular genomics, single-cell biology, pharmacology, and gene editing technology are transforming our understanding of brain arteriovenous malformations (bAVMs) - a leading cause of pediatric hemorrhagic stroke. Once considered static anatomical defects, bAVMs are now recognized as dynamic, genetically driven lesions resulting from somatic mutations in KRAS, BRAF, and pathways involved in arteriovenous specification, angiogenesis, and vascular remodeling. By integrating human genetics, animal models, and endovascular innovations, researchers have uncovered convergent mechanisms that link endothelial Ras/MAPK hyperactivation to abnormal vessel growth and higher rupture risk. These insights provide a foundation for precision medicine approaches that combine molecular diagnostics - such as liquid or endoluminal biopsies - with mutation-specific pharmacotherapies and emerging CRISPR-based gene editing strategies. We suggest that genotype-guided interventions, tailored by spatial and developmental cerebrovascular context, could ultimately reclassify bAVMs from surgically incurable malformations to treatable molecular conditions.

Humans↗

PubMed2026

De Novo TRIO Missense Variants Disrupt Ras-GEF Domains and Cause Congenital Ventriculomegaly and Hydrocephalus.

Congenital hydrocephalus (CH), characterized by congenital ventriculomegaly (CV), affects approximately 0.5-1 per 1000 live births and is a common cause of pediatric neurosurgical intervention, yet its genetic architecture remains incompletely defined. We report a child with syndromic CH requiring cerebrospinal fluid diversion who harbored a pathogenic de novo missense variant in TRIO (c.3232C > T; p.(Arg1078Trp)), a gene previously associated with autosomal dominant neurodevelopmental disorders featuring variable head circumference. This case prompted systematic evaluation of TRIO variation in our CV/CH cohort (2,697 patient-parent trios) using exome sequencing. We identified five additional unrelated probands with de novo TRIO variants, including two novel substitutions affecting the same residue within the Ras-GEF1 domain (p.(Glu1299Lys) and p.(Glu1299Gly)), yielding significant gene-level enrichment for protein-damaging de novo variants (adjusted p = 6.12 × 10-5). All affected individuals exhibited CV, frequently accompanied by developmental delay and additional structural brain abnormalities. In silico structural modeling predicted that associated variants destabilize critical TRIO Ras-GEF domains required for Rho GTPase activation. Analysis of single-nucleus transcriptomic data from the developing human neocortex revealed enrichment of TRIO expression in multipotent progenitor populations. A systematic literature review identified six additional individuals with TRIO de novo variants and reported CV or CH, including an unrelated patient with the same p.(Arg1078Trp) substitution. Together, these findings expand the phenotypic spectrum associated with pathogenic TRIO variation to include CV/CH and support TRIO as a clinically relevant gene in the genetic evaluation of syndromic CV/CH patients.

Humans↗

PubMed2025

The RNA-binding protein TRIM71 is essential for hearing in humans and mice and times auditory sensory organ development.

The RNA-binding protein TRIM71 is essential for brain development, and recent genetic studies in humans have identified TRIM71 as a risk gene for congenital hydrocephal-us (CH). Here, we show that monoallelic missense mutations in TRIM71 are associated with hearing loss (HL) and inner ear aplasia in humans. Utilizing conditional Trim71 knockout mice carrying a CH and HL-associated mutation, we demonstrate that loss of TRIM71 function during early otic development (embryonic day 9 to 10) causes severe HL. While inner ear morphogenesis occurs normally in Trim71 knockout mice, we find that early otic loss of TRIM71 function disrupts the highly stereotyped timing of cell cycle exit and differentiation within the inner ear auditory sensory organ (cochlea), resulting in the premature formation and innervation of mechanosensory hair cells. Transcriptomic profiling of Trim71-deficient cochlear progenitor cells identifies Inhba and Tgfbr2 as targets of TRIM71 repression, and our analysis of Inhba-Tgfbr1 double knockout mice indicates that TRIM71 maintains hair cell progenitors in a proliferative and undifferentiated state by restricting TGFβ-type signaling. Characterization of hair cells and their associated neurons in adult Trim71 knockout mice revealed reduced presynaptic terminals and neuronal degeneration in the outer hair cell region, providing a basis for the observed hearing deficits in Trim71 knockout mice.

Animals↗

PubMed2024

Genetics and molecular pathophysiology of normal pressure hydrocephalus.

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by dilation of the cerebral ventricles without increased cerebral pressure. Patients typically present with cognitive impairment, gait abnormalities, and urinary incontinence. Despite current guidelines for diagnosis and surgical intervention, there is little consensus on the pathophysiology of iNPH. Familial cases and genomic studies of iNPH have recently suggested an underappreciated role of genetics in disease pathogenesis, implicating mechanisms ranging from dysregulated CSF dynamics to underlying neurodegenerative or neuroinflammatory processes. In this paper, the authors provide a brief review of genetic insights and candidate genes for iNPH, highlighting the continued importance of integrated genetic analysis and clinical studies to advance iNPH management.

Humans↗