Generation and characterization of a zebrafish gain-of-function ACOX1 Mitchell disease model.

Background: Mitchell syndrome is a rare, neurodegenerative disease caused by an ACOX1 gain-of-function mutation (c.710A>G; p.N237S), with fewer than 20 reported cases. Affected patients present with leukodystrophy, seizures, and hearing loss. ACOX1 serves as the rate-limiting enzyme in peroxisomal beta-oxidation of very long-chain fatty acids. The N237S substitution has been shown to stabilize the active ACOX1 dimer, resulting in dysregulated enzymatic activity, increased oxidative stress, and glial damage. Mitchell syndrome lacks a vertebrate model, limiting insights into the pathophysiology of ACOX1-driven white matter damage and neuroinflammatory insults. Methods: We report a patient presenting with rapidly progressive white matter damage and neurological decline, who was eventually diagnosed with an ACOX1 N237S mutation through whole genome sequencing. We developed a zebrafish model of Mitchell syndrome using transient ubiquitous overexpression of the human ACOX1 N237S variant tagged with GFP. We assayed zebrafish behavior, oligodendrocyte numbers, expression of white matter and inflammatory transcripts, and analysis of peroxisome counts. Results: The patient experienced progressive leukodystrophy and died 2 years after presentation. The transgenic zebrafish showed a decreased swimming ability, which was restored with the reactive microglia-targeted antioxidant dendrimer-N-acetyl-cysteine conjugate. The mutants showed no effect on oligodendrocyte counts but did display activation of the integrated stress response (ISR). Using a novel SKL-targeted mCherry reporter, we found that mutants had reduced density of peroxisomes. Conclusions: We developed a vertebrate (zebrafish) model of Mitchell syndrome using transient ubiquitous overexpression of the human ACOX1 N237S variant. The transgenic mutants exhibited motor impairment and showed signs of activated ISR, but interestingly, there were no changes in oligodendrocyte counts. However, the mutants exhibited a deficiency in the number of peroxisomes, suggesting a possible shared mechanism with the Zellweger spectrum disorders.

Early genetic testing in pediatric epilepsy: Diagnostic and cost implications.

The identification of numerous genetically based epilepsies has resulted in the widespread use of genetic testing to inform epilepsy etiology. Our study aims to investigate whether a difference exists in the diagnostic evaluation and healthcare-related cost expenditures of pediatric patients with epilepsy of unknown etiology who receive a genetic diagnosis through multigene epilepsy panel (MEP) testing and comparing those who underwent early (EGT) versus late genetic testing (LGT). Testing was defined as early (less than 1 year), or late (more than 1 year), following clinical epilepsy diagnosis. A retrospective chart review of pediatric individuals (1-17 years) with epilepsy of unknown etiology who underwent multigene epilepsy panel (MEP) testing identified 28 of 226 (12%) individuals with a pathogenic epilepsy variant [EGT n = 8 (29%); LGT n = 20 (71%)]. The average time from clinical epilepsy diagnosis to genetic diagnosis was 0.25 years (EGT), compared with 7.1 years (LGT). The EGT cohort underwent fewer metabolic tests [EGT n = 0 (0%); LGT n = 16 (80%) (P < 0.01)] and invasive procedures [EGT n = 0 (0%); LGT n = 5 (25%) (P = 0.06)]. Clinical management changes implemented due to genetic diagnosis occurred in 10 (36%) patients [EGT n = 2 (25%); LGT n = 8 (40%) (P = 0.76)]. Early genetic testing with a MEP in pediatric patients with epilepsy of unknown etiology who receive a genetic diagnosis is associated with fewer non-diagnostic tests and invasive procedures and reduced estimated overall healthcare-related costs. PLAIN LANGUAGE SUMMARY: This study aims to investigate whether a difference exists in the diagnostic evaluation and cost expenditures of pediatric patients (1-17 years) with epilepsy of unknown cause who are ultimately diagnosed with a genetic cause of epilepsy through multigene epilepsy panel testing and comparing those who underwent early testing (less than 1 year) versus late testing (more than 1 year) after clinical epilepsy diagnosis. Of the 28 of 226 individuals with a confirmed genetic cause of epilepsy on multigene epilepsy panel testing, performing early testing was associated with fewer non-diagnostic tests, fewer invasive procedures and reduced estimated overall healthcare-related costs.

SARS-CoV-2 Infection and Increased Risk for Pediatric Stroke.

BACKGROUND: There is an increased risk of stroke in adults with severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019 [COVID-19]) infection, but whether there is a similar association with stroke in children is unclear. Our objective was to determine whether there is a correlation between COVID-19 infection, multisystem inflammatory syndrome in children (MIS-C), and pediatric ischemic stroke. METHODS: This was a retrospective, population-based cohort analysis between March 1, 2020, and June 30, 2021, conducted at a children's hospital. Pediatric patients with a diagnosis of ischemic stroke were identified using ICD-10 diagnoses of ischemic stroke, cerebrovascular accident, or cerebral infarction. RESULTS: We identified 16 patients, seven male and nine female, with ischemic stroke. Ages were 8 months to 17 years (median 11.5 years). More Asian (6%) and black (13%) patients had strokes compared with population prevalence (2% each, respectively). No patients had active COVID-19 infection. COVID-19 antibodies were identified in five of 11 patients tested (45%), of whom three were diagnosed with MIS-C. 82% of the strokes occurred between February and May 2021. The peak incidence was in February 2021, which was two months after peak incidence of pediatric cases of COVID-19 and one month after the peak of MIS-C cases. CONCLUSIONS: Our study suggests that prior COVID-19 infection, but not acute infection, is correlated with a risk for stroke in the pediatric population. The risk for stroke appears to be distinct from the risk for MIS-C.

Celiac Disease in Children: An Association With Drug-Resistant Epilepsy.

BACKGROUND: Neurological manifestations are commonly reported in patients with celiac disease (CD). We aimed to characterize epilepsy features in a pediatric population with CD and the effect of a gluten-free diet (GFD) on seizure burden. METHODS: A retrospective chart review was performed on pediatric patients treated at the University of Utah and Primary Children's Hospital in Salt Lake City, Utah, with both epilepsy and CD and compared with a control group with epilepsy only. RESULTS: We identified 56 patients with epilepsy and biopsy-confirmed CD (n = 36, 64%) or elevated tissue transglutaminase antibodies (tTG-Ab) without biopsy-confirmed CD (n = 20, 36%). Age- and gender-matched controls were selected from patients with epilepsy only (n = 168). Patients with biopsy-proven CD or positive tTG-Ab had high percentage of drug-resistant epilepsy (DRE) compared with the control group (P < 0.05). Age at seizure onset preceded the diagnosis of CD on average by 5.9 years for patients with DRE (P < 0.01) compared with 2.2 years for those with drug-responsive epilepsy. Adhering to a GFD reduced seizure frequency or resulted in weaning dosage or weaning off of one or more antiseizure medications in a majority of patients with DRE. CONCLUSIONS: DRE was more prevalent in pediatric patients with biopsy-confirmed CD and positive tTG-Ab compared with the control group (which included childhood epilepsy syndromes), but comparable with the prevalence of DRE in the general population. Adherence to a GFD in combination with antiseizure medications appears to reduce seizure burden for those with CD and DRE.

Pediatric Migraine Phenomena and Variants: Don't Let Them Go Over Your Head.

PURPOSE OF REVIEW: Primary care providers, general pediatric neurologists, and other related subspecialty providers require a clear understanding of pediatric migraine with typical aura and its variants. RECENT FINDINGS: We highlight some of the genetic mutations known to contribute to specific types of migraine with aura, discuss the ophthalmologic phenomena of migraine and call attention to some of the earliest manifestations of migraine in children, many of which have correlates in adulthood. While the majority of headaches in children are migraine with or without aura or tension type, many migraine and aura variants exist. Early and accurate diagnosis of episodic syndromes associated with migraine, as defined by the 2018 ICHD-3 criteria, can help to reduce unnecessary imaging, referrals, cost and anxiety, thereby benefiting patients and their families.