Publications by authors named "Velda X Han"

Background: Bilateral hemorrhagic thalamic lesions in dengue encephalitis resemble lesions seen in acute necrotizing encephalopathy (ANE). We investigate whether dengue-associated ANE (DANE) should be considered an ANE variant or a mimic.

Methods: Systematic review of dengue encephalitis literature from PubMed and SCOPUS (inception to December 31, 2022).

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Article Synopsis
  • Researchers wanted to create clear rules for identifying a sickness called 'infection-triggered encephalopathy syndrome (ITES)' and five related types of it.
  • They talked to expert doctors for a long time to agree on how to recognize ITES by checking for things like infection, symptoms, and brain scans.
  • With these new definitions, doctors can better understand ITES and help with future studies and treatments for it.
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Background: Kabuki syndrome (KS) is a genetic disorder caused by DNA mutations in KMT2D, a lysine methyltransferase that methylates histones and other proteins, and therefore modifies chromatin structure and subsequent gene expression. Ketones, derived from the ketogenic diet, are histone deacetylase inhibitors that can 'open' chromatin and encourage gene expression. Preclinical studies have shown that the ketogenic diet rescues hippocampal memory neurogenesis in mice with KS via the epigenetic effects of ketones.

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Objectives: There is lack of evidence-based information on the use and timing of endotracheal intubation (ETI) in children with prehospital status epilepticus (SE).

Methods: The aim of this study was to investigate ETI use, timing, risk factors, and outcomes in children presenting to a single-center children's emergency (CE) with prehospital SE, over a 5-year period.

Results: A total of 118 events involving children presenting to CE with ongoing prehospital SE were included, and 39% (46/118) of the events required ETI.

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Background: Preclinical studies suggest synergistic effects of maternal inflammatory exposures on offspring neurodevelopment, but human studies have been limited.

Objectives: To examine the cumulative association and potential interactions between seven maternal exposures related to inflammation and child attention-deficit/hyperactivity disorder (ADHD).

Methods: We conducted a population-based cohort study of children born from July 2001 to December 2011 in New South Wales, Australia, and followed up until December 2014.

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Background: Neurological complications with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron variant have been reported in adults; however, there are little data in the pediatric population. We aimed to report on the prevalence and clinical characteristics of children with neurological symptoms during the SARS-CoV-2 omicron wave.

Methods: This was a single-center, retrospective cohort review of children (<18 years old) hospitalized for SARS-CoV-2 infection from December 2, 2021, to June 30, 2022.

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Objective: Infection-triggered encephalopathy syndromes (ITES) are potentially devastating neuroinflammatory conditions. Although some ITES syndromes have recognisable MRI neuroimaging phenotypes, there are otherwise few biomarkers of disease. Early detection to enable immune modulatory treatments could improve outcomes.

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Background: Defining the presence of acute and chronic brain inflammation remains a challenge to clinicians due to the heterogeneity of clinical presentations and aetiologies. However, defining the presence of neuroinflammation, and monitoring the effects of therapy is important given its reversible and potentially damaging nature. We investigated the utility of CSF metabolites in the diagnosis of primary neuroinflammatory disorders such as encephalitis and explored the potential pathogenic role of inflammation in epilepsy.

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Neurodevelopmental disorders (NDDs), including autism-spectrum disorders (ASD) and Tourette syndrome (TS) are common brain conditions which often co-exist, and have no approved treatments targeting disease mechanisms. Accumulating literature implicates the immune system in NDDs, and transcriptomics of post-mortem brain tissue has revealed an inflammatory signal. We interrogated two RNA-sequencing datasets of ASD and TS and identified differentially expressed genes, to explore commonly enriched pathways through GO, KEGG, and Reactome.

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Background: Acute necrotizing encephalopathy of childhood (ANEC) is a rare parainfectious neurological disorder. ANEC is associated with a high mortality rate and poor neurological outcomes. ANEC is postulated to arise from immune-mediated or metabolic processes driven by viral infections.

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Article Synopsis
  • A significant increase in adolescents and young adults seeking help for functional tic-like behaviors (FTLBs) was observed from 2019 to 2022, prompting an international registry study to better understand this phenomenon.
  • Data was collected from 10 tertiary centers, involving 294 patients primarily aged 12-25, revealing high rates of complex movements and vocalizations, with a notable link to anxiety, depression, and autism spectrum disorders.
  • Treatment outcomes showed that most patients did not benefit from tic-suppressing medications, highlighting the need for further research on effective treatments and the impact of social media exposure on FTLBs.
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Article Synopsis
  • * A cohort of over 18,000 children exposed to maternal autoimmune disease was compared to nearly 37,000 unexposed children in New South Wales, Australia, with data collected on maternal health and child infections before the age of 2, and ASD diagnoses by age 9.
  • * Although both maternal autoimmune disease and childhood infections were associated with increased odds of ASD, the study found no evidence of a synergistic or additive interaction between the two factors, suggesting that one does not amplify the effects
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Background: Epileptic (previously infantile) spasms is the most common epileptic encephalopathy occurring during infancy and is frequently associated with abnormal neurodevelopmental outcomes. Epileptic spasms have a diverse range of known (genetic, structural) and unknown aetiologies. High dose corticosteroid treatment for 4 weeks often induces remission of spasms, although the mechanism of action of corticosteroid is unclear.

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Background: Neuroinflammatory diseases such as encephalitis, meningitis, multiple sclerosis and other neurological diseases with inflammatory components, have demonstrated a need for diagnostic biomarkers to define treatable and reversible neuroinflammation. The development and clinical validation of a targeted translational inflammation panel using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) could provide early diagnosis, rapid treatment and insights into neuroinflammatory mechanisms.

Methods: An inflammation panel of 13 metabolites (neopterin, tryptophan, kynurenine, kynurenic acid, 3-hydroxykynurenine, xanthurenic acid, anthranilic acid, 3-hydroxyanthranilic acid, quinolinic acid, picolinic acid, arginine, citrulline and methylhistamine) was measured based on a simple precipitation and filtration method using minimal CSF volume.

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Aim: To report the prevalence and clinical characteristics of children with rapid onset functional tic-like behaviours during the COVID-19 pandemic.

Methods: Single centre, retrospective cohort study of children (<18 years) referred to the tic clinic from January 2018 to July 2021. We calculate the prevalence of newly diagnosed functional tics, and compare the clinical features to chronic tic disorder/Tourette syndrome (CTD/TS).

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Background: The type 1 interferonopathy, Aicardi-Goutières syndrome 6 (AGS6), is classically caused by biallelic ADAR mutations whereas dominant ADAR mutations are associated with dyschromatosis symmetrica hereditaria (DSH). The unique dominant ADAR c.3019G>A variant is associated with neurological manifestations which mimic spastic paraplegia and cerebral palsy (CP).

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Inflammation is increasingly recognised to play a major role in gene-environment interactions in neurodevelopmental disorders (NDDs). The effects of aberrant immune responses to environmental stimuli in the mother and in the child can affect neuroimmune signalling that is central to brain development. Toll-like receptors (TLR) are the best known innate immune pattern and danger recognition sensors to various environmental threats.

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Janus kinase (JAK) 1 inhibition represents a precision medicine approach in the treatment of Aicardi-Goutières syndrome (AGS), through targeting of type I interferon-mediated cell signalling. Blood interferon mRNAseq has been proposed as a biomarker of disease with utility in therapeutic monitoring. Objective cerebrospinal fluid (CSF) biomarkers tracking treatment efficacy are currently lacking.

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Maternal health during pregnancy plays a major role in shaping health and disease risks in the offspring. The maternal immune activation hypothesis proposes that inflammatory perturbations in utero can affect fetal neurodevelopment, and evidence from human epidemiological studies supports an association between maternal inflammation during pregnancy and offspring neurodevelopmental disorders (NDDs). Diverse maternal inflammatory factors, including obesity, asthma, autoimmune disease, infection and psychosocial stress, are associated with an increased risk of NDDs in the offspring.

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Inflammation is increasingly recognized as a cause or consequence of common problems of humanity including obesity, stress, depression, pollution and disease states such as autoimmunity, asthma, and infection. Maternal immune activation (MIA), triggered by both acute and systemic chronic inflammation, is hypothesized to be one of the mechanisms implicated in the pathogenesis of neurodevelopmental disorders (NDD). Although there is substantial preclinical evidence to support the MIA hypothesis, the human evidence is disparate.

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Although genetic variation is a major risk factor of neurodevelopmental disorders, environmental factors during pregnancy and early life are also important in disease expression. Animal models demonstrate that maternal inflammation causes fetal neuroinflammation and neurodevelopmental deficits, and brain transcriptomics of neurodevelopmental disorders in humans show upregulated differentially expressed genes are enriched in immune pathways. We prospectively recruited 200 sequentially referred children with tic disorders/obsessive-compulsive disorder (OCD), 100 autoimmune neurological controls, and 100 age-matched healthy controls.

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