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Andrew T Hale

Publications and source records attributed to Andrew T Hale.

9 recordsLinked to original sources
PubMed2026

Chiari I malformation.

Chiari I malformation (CM1), the most common structural hindbrain disorder in humans, is traditionally characterized by the downward displacement of the cerebellar tonsils through the foramen magnum. However, this definition does not reflect the variability in clinical presentation, natural history and treatment response of this disorder. Some individuals with minimal tonsillar descent have severe neurological symptoms and syringomyelia, whereas others with extensive descent remain asymptomatic. Emerging evidence from neuroimaging, developmental biology and human genetics indicates that CM1 is not a single anatomical entity but a spectrum of disorders resulting from disruptions in coordinated growth and homeostasis across the cerebellum, posterior fossa, craniocervical junction, cerebrospinal fluid and neurovascular systems. CM1 may be best understood as a disorder of disrupted developmental scaling, in which the tightly regulated relationships between cerebellar growth and cranial accommodation are altered within a dynamic neurovascular and cerebrospinal fluid environment. In this context, tonsillar herniation is a geometric consequence rather than the primary disease process. This Primer synthesizes current knowledge on the epidemiology, mechanisms, diagnosis and management of CM1 across the lifespan. We highlight advances in neuroimaging, genomics and phenomics that support a shift from anatomy-based definitions towards an integrated genomic-phenomic classification.

Humans↗
PubMed2026

De novo chromatin remodelling variants in sporadic Chiari 1 malformation.

Chiari 1 malformation (CM1) is the most common congenital malformation of the human hindbrain. Although prior studies have implicated chromatin-remodeling genes in CM1, the de novo genetic architecture and underlying neurodevelopmental mechanisms remain incompletely defined. To investigate the molecular genetics of a novel familial form of CM1 linked with syringomyelia and tethered cord and determine whether rare, damaging de novo variants (DNVs) contribute to sporadic CM1 risk with gene- and pathway-level resolution, we performed whole-exome sequencing in an ultra-rare multigenerational family with CM1 and associated spinal pathology, and in the largest assembled trio-based cohort to date, comprising 1,585 proband-parent trios with sporadic, idiopathic CM1 (2017-2025). The comparison cohort included 1,798 unaffected control siblings. Clinical phenotyping was by systematic medical record review. Structural domain mapping, in silico modeling, and integration with single-cell transcriptomic data from developing human cerebellum was conducted to assess biological plausibility. A heterozygous loss-of-function variant in CHD3 segregated with CM1 and syringomyelia in a multigenerational family. In the trio-based cohort, rare protein-altering DNVs were significantly enriched across multiple chromodomain helicase DNA-binding (CHD) genes, including CHD1, CHD3, CHD4, and CHD8, exceeding gene-specific mutation expectations (protein-damaging variants: P = 1.3 × 10-9; predicted loss-of-function variants: P = 8.6 × 10-5). CHD1 contained two pathogenic DNVs (p.A999D and p.E984K). CHD4 (p.D744N, p.T1813P, and p.I1102T) and CHD8 (p.R1402X, p.R1472X, and p.R2035X) each contained three new DNVs. Variants clustered within conserved ATPase, helicase, and chromodomain regions essential for chromatin remodeling, and these patients frequently had comorbid developmental delay and related neurodevelopmental features. Single-cell transcriptomic analyses demonstrated enrichment in Purkinje cells and inhibitory neurons of midgestational cerebellum, where CHD gene products form a coherent chromatin-regulatory network. Rare, large-effect DNVs that disrupt chromatin-remodeling programs contribute to sporadic CM1, implicating genetically encoded dysregulation of cerebellar development as a central disease mechanism. Exome sequencing may complement surgical evaluation of children with sporadic CM1, particularly when accompanied by neurodevelopmental concerns, informing prognosis and family counseling.

de novo variants↗
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

Genetically Guided Pharmacotherapy for Structural Neurovascular Lesions.

Structural neurovascular lesions (SNVLs)-arteriovenous malformations, cavernous malformations, and vein of Galen aneurysmal malformations, among others-have historically been treated using neurosurgical, radiotherapeutic, and endovascular approaches. However, lesion size, location, and presence of high-risk angioarchitectural features preclude many patients from receiving these treatments. Advances in human genetics and cerebrovascular biology have redefined SNVLs as dynamic, genetically driven lesions where sporadic cases are caused by somatic variants. Intriguingly, many SNVL-causing variants are also oncogenic and active drug targets. These data provide the rationale for a genetically driven taxonomy to guide targeted therapeutic selection. In this commentary, we synthesize efforts toward pharmacologic treatments of SNVLs and highlight how variant-specific or pathway-modulating therapies may be investigated, incorporating key considerations in molecular diagnosis, cerebrovascular biology, and molecular and phenotypic outcome measures, in forthcoming clinical trials. Together, these advances support the investigation of pharmacologic treatment strategies in carefully selected patients with SNVLs.

Journal Article↗
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

Integrative genomics elucidates the evolutionary, temporal, and developmental origins of a hydrocephalus risk gene.

INTRODUCTION: A prior integrative, multi-omics human genetics and functional genomics study identified maelstrom (MAEL), a gene involved in regulation of DNA transposon activity and genome structure, as a transcriptome-wide predictor of hydrocephalus (HC) in the brain cortex. Here we expand on this discovery and further characterize the evolutionary origin and expression of MAEL across developmental timescales and cell-lineages in the neonatal human brain towards a mechanistic understanding how variation in MAEL expression may cause HC. OBJECTIVE: To characterize the evolutionary, temporal, developmental, and lineages of MAEL expression in HC and the developing human brain. METHODS: Ensembl was used to delineate the evolution and taxonomy of MAEL across species. Analysis of single-cell RNA sequencing (scRNA-seq) of 49 brain regions across pre- and post-natal timescales from the Developing Human Brain Atlas (Allen Institute) identified temporal and spatial MAEL expression patterns. We quantified MAEL expression in primary cortical brain tissue obtained during the surgical treatment of HC. RESULTS: We performed taxonomic gene-mapping to define the evolutionary origin of MAEL to assess suitability for mechanistic characterization in vitro and in vivo across species. We find that MAEL is among the top 0.01% human-specific genes and < 50% sequence homology among commonly used model organisms with highly divergent functions, necessitating mechanistic validation in human tissue. scRNA-seq of the non-disease prenatal human brain identified MAEL expression enriched in cortical excitatory neurons, which was recapitulated in primary HC brain tissue obtained during surgery. Finally, using scRNA-seq of primary HC brain tissue, we functionally validated reduced MAEL expression, consistent with a prior human TWAS analysis. CONCLUSIONS: We identify the evolutionary, temporal, and developmental expression pattern of MAEL in the neonatal human brain. We also provide direct evidence for reduced MAEL expression in human HC brain tissue. These data, at least in part, implicate reduced MAEL expression underlying human HC across etiologies.

Journal Article↗