Developmental epileptic encephalopathy in DLG4-related synaptopathy.

OBJECTIVE: The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail. We describe here the phenotypic spectrum of epilepsy and associated comorbidities in patients with DLG4-related synaptopathy. METHODS: We included 35 individuals with a DLG4 variant and epilepsy as part of a multicenter study. The DLG4 variants were detected by the referring laboratories. The degree of ID, hypotonia, developmental delay, and motor disturbances were evaluated by the referring clinician. Data on awake and sleep electroencephalography (EEG) and/or video-polygraphy and brain magnetic resonance imaging were collected. Antiseizure medication response was retrospectively assessed by the referring clinician. RESULTS: A large variety of seizure types was reported, although focal seizures were the most common. Encephalopathy related to status epilepticus during slow-wave sleep (ESES)/developmental epileptic encephalopathy with spike-wave activation during sleep (DEE-SWAS) was diagnosed in >25% of the individuals. All but one individual presented with neurodevelopmental delay. Regression in verbal and/or motor domains was observed in all individuals who suffered from ESES/DEE-SWAS, as well as some who did not. We could not identify a clear genotype-phenotype relationship even between individuals with the same DLG4 variants. SIGNIFICANCE: Our study shows that a subgroup of individuals with DLG4-related synaptopathy have DEE, and approximately one fourth of them have ESES/DEE-SWAS. Our study confirms DEE as part of the DLG4-related phenotypic spectrum. Occurrence of ESES/DEE-SWAS in DLG4-related synaptopathy requires proper investigation with sleep EEG.

Rapidly developed, optimized, and applied wastewater surveillance system for real-time monitoring of low-incidence, high-impact MPOX outbreak.

Recent MPOX viral resurgences have mobilized public health agencies around the world. Recognizing the significant risk of MPOX outbreaks, large-scale human testing, and immunization campaigns have been initiated by local, national, and global public health authorities. Recently, traditional clinical surveillance campaigns for MPOX have been complemented with wastewater surveillance (WWS), building on the effectiveness of existing wastewater programs that were built to monitor SARS-CoV-2 and recently expanded to include influenza and respiratory syncytial virus surveillance in wastewaters. In the present study, we demonstrate and further support the finding that MPOX viral fragments agglomerate in the wastewater solids fraction. Furthermore, this study demonstrates that the current, most commonly used MPOX assays are equally effective at detecting low titers of MPOX viral signal in wastewaters. Finally, MPOX WWS is shown to be more effective at passively tracking outbreaks and/or resurgences of the disease than clinical testing alone in smaller communities with low human clinical case counts of MPOX.

Vorinostat Improves Myotonic Dystrophy Type 1 Splicing Abnormalities in DM1 Muscle Cell Lines and Skeletal Muscle from a DM1 Mouse Model.

Myotonic dystrophy type 1 (DM1), the most common form of adult muscular dystrophy, is caused by an abnormal expansion of CTG repeats in the 3' untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. The expanded repeats of the DMPK mRNA form hairpin structures in vitro, which cause misregulation and/or sequestration of proteins including the splicing regulator muscleblind-like 1 (MBNL1). In turn, misregulation and sequestration of such proteins result in the aberrant alternative splicing of diverse mRNAs and underlie, at least in part, DM1 pathogenesis. It has been previously shown that disaggregating RNA foci repletes free MBNL1, rescues DM1 spliceopathy, and alleviates associated symptoms such as myotonia. Using an FDA-approved drug library, we have screened for a reduction of CUG foci in patient muscle cells and identified the HDAC inhibitor, vorinostat, as an inhibitor of foci formation; SERCA1 (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase) spliceopathy was also improved by vorinostat treatment. Vorinostat treatment in a mouse model of DM1 (human skeletal actin-long repeat; HSALR) improved several spliceopathies, reduced muscle central nucleation, and restored chloride channel levels at the sarcolemma. Our in vitro and in vivo evidence showing amelioration of several DM1 disease markers marks vorinostat as a promising novel DM1 therapy.

Timing of therapy and neurodevelopmental outcomes in 18 families with pyridoxine-dependent epilepsy.

BACKGROUND: Seventy-five percent of patients with pyridoxine-dependent epilepsy due to α-aminoadipic semialdehyde dehydrogenase deficiency (PDE-ALDH7A1) suffer intellectual developmental disability despite pyridoxine treatment. Adjunct lysine reduction therapies (LRT), aimed at lowering putative neurotoxic metabolites, are associated with improved cognitive outcomes. However, possibly due to timing of treatment, not all patients have normal intellectual function. METHODS: This retrospective, multi-center cohort study evaluated the effect of timing of pyridoxine monotherapy and pyridoxine with adjunct LRT on neurodevelopmental outcome. Patients with confirmed PDE-ALDH7A1 with at least one sibling with PDE-ALDH7A1 and a difference in age at treatment initiation were eligible and identified via the international PDE registry, resulting in thirty-seven patients of 18 families. Treatment regimen was pyridoxine monotherapy in ten families and pyridoxine with adjunct LRT in the other eight. Primary endpoints were standardized and clinically assessed neurodevelopmental outcomes. Clinical neurodevelopmental status was subjectively assessed over seven domains: overall neurodevelopment, speech/language, cognition, fine and gross motor skills, activities of daily living and behavioral/psychiatric abnormalities. RESULTS: The majority of early treated siblings on pyridoxine monotherapy performed better than their late treated siblings on the clinically assessed domain of fine motor skills. For siblings on pyridoxine and adjunct LRT, the majority of early treated siblings performed better on clinically assessed overall neurodevelopment, cognition, and behavior/psychiatry. Fourteen percent of the total cohort was assessed as normal on all domains. CONCLUSION: Early treatment with pyridoxine and adjunct LRT may be beneficial for neurodevelopmental outcome. When evaluating a more extensive neurodevelopmental assessment, the actual impairment rate may be higher than the 75% reported in literature. TAKE- HOME MESSAGE: Early initiation of lysine reduction therapies adjunct to pyridoxine treatment in patients with PDE-ALDH7A1 may result in an improved neurodevelopmental outcome.

Quantitation of phosphatidylethanols in dried blood spots to determine rates of prenatal alcohol exposure in Ontario.

BACKGROUND: Estimating rates of prenatal alcohol exposure (PAE) in a population is necessary to ensure that proper medical and social supports and interventions are in place. This study sought to estimate PAE in Ontario, Canada by quantifying phosphatidylethanol (PEth) homologues in over 2000 residual neonatal dried blood spots (DBS). METHODS: A random selection of 2011 residual DBS collected over a 1-week time period were anonymized and extracted. A targeted liquid chromatography-mass spectrometry method was used to quantify 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanol (PEth (16:0/18:1) or POPEth), the clinically accepted biomarker, and six additional PEth homologues. A POPEth level above the United States Drug Testing Laboratories (USDTL) cutoff up to 4 weeks predelivery was indicative of PAE. All PEth homologues were correlated to one another and logistic regression was used to determine the association between PAE status and infant characteristics. RESULTS: The estimated rate of PAE in Ontario, up to the last 4 weeks of gestation, was 15.5% (POPEth >28.5 nM). Most PEth homologues were moderately to strongly correlated to one another. A low birth weight and preterm birth were both associated with PAE, while being small for gestational age had lower odds of PAE. CONCLUSIONS: The results of this study suggest that PAE may be more prevalent in Ontario than previous estimates by self-report or meconium testing. These findings support the need to consider the effectiveness of current interventions and the design of new interventions to address this significant public health issue.

DLG4-related synaptopathy: a new rare brain disorder.

PURPOSE: Postsynaptic density protein-95 (PSD-95), encoded by DLG4, regulates excitatory synaptic function in the brain. Here we present the clinical and genetic features of 53 patients (42 previously unpublished) with DLG4 variants. METHODS: The clinical and genetic information were collected through GeneMatcher collaboration. All the individuals were investigated by local clinicians and the gene variants were identified by clinical exome/genome sequencing. RESULTS: The clinical picture was predominated by early onset global developmental delay, intellectual disability, autism spectrum disorder, and attention deficit-hyperactivity disorder, all of which point to a brain disorder. Marfanoid habitus, which was previously suggested to be a characteristic feature of DLG4-related phenotypes, was found in only nine individuals and despite some overlapping features, a distinct facial dysmorphism could not be established. Of the 45 different DLG4 variants, 39 were predicted to lead to loss of protein function and the majority occurred de novo (four with unknown origin). The six missense variants identified were suggested to lead to structural or functional changes by protein modeling studies. CONCLUSION: The present study shows that clinical manifestations associated with DLG4 overlap with those found in other neurodevelopmental disorders of synaptic dysfunction; thus, we designate this group of disorders as DLG4-related synaptopathy.

Newborn Screening for Spinal Muscular Atrophy: Ontario Testing and Follow-up Recommendations.

BACKGROUND: Spinal muscular atrophy (SMA) is characterized by the progressive loss of motor neurons causing muscle atrophy and weakness. Nusinersen, the first effective SMA therapy was approved by Health Canada in June 2017 and has been added to the provincial formulary of all but one Canadian province. Access to this effective therapy has triggered the inclusion of SMA in an increasing number of Newborn Screening (NBS) programs. However, the range of disease-modifying SMN2 gene copy numbers encountered in survival motor neuron 1 (SMN1)-null individuals means that neither screen-positive definition nor resulting treatment decisions can be determined by SMN1 genotype alone. We outline an approach to this challenge, one that specifically addresses the case of SMA newborns with four copies of SMN2. OBJECTIVES: To develop a standardized post-referral evaluation pathway for babies with a positive SMA NBS screen result. METHODS: An SMA NBS pilot trial in Ontario using first-tier MassARRAY and second-tier multi-ligand probe amplification (MLPA) was launched in January 2020. Prior to this, Ontario pediatric neuromuscular disease and NBS experts met to review the evidence regarding the diagnosis and treatment of children with SMA as it pertained to NBS. A post-referral evaluation algorithm was developed, outlining timelines for patient retrieval and management. CONCLUSIONS: Ontario's pilot NBS program has created a standardized path to facilitate early diagnosis of SMA and initiation of treatment. The goal is to provide timely access to those SMA infants in need of therapy to optimize motor function and prolong survival.

The Covid-19 Pandemic Has Exposed Opportunities To Strengthen Our Health Research Systems.

Professor Sir Mark Walport, FRS, FMed Sci, FRCP, physicianscientist, academic leader and visionary health research planner, was the recipient of the 2020 Henry G. Friesen International Prize in Health Research. He is a former Chief Executive, UK Research and Innovation (UKRI) and UK government's Chief Scientific Advisor. He continues to be a champion of fundamental science in health research, engineering, technology and innovation, and is a major spokesperson on COVID-19 pandemic trends at the global level.

Separating the Wheat from the Chaff: The Use of Upstream Regulator Analysis to Identify True Differential Expression of Single Genes within Transcriptomic Datasets.

The development of DNA microarray and RNA-sequencing technology has led to an explosion in the generation of transcriptomic differential expression data under a wide range of biologic systems including those recapitulating the monogenic muscular dystrophies. Data generation has increased exponentially due in large part to new platforms, improved cost-effectiveness, and processing speed. However, reproducibility and thus reliability of data remain a central issue, particularly when resource constraints limit experiments to single replicates. This was observed firsthand in a recent rare disease drug repurposing project involving RNA-seq-based transcriptomic profiling of primary cerebrocortical cultures incubated with clinic-ready blood-brain penetrant drugs. Given the low validation rates obtained for single differential expression genes, alternative approaches to identify with greater confidence genes that were truly differentially expressed in our dataset were explored. Here we outline a method for differential expression data analysis in the context of drug repurposing for rare diseases that incorporates the statistical rigour of the multigene analysis to bring greater predictive power in assessing individual gene modulation. Ingenuity Pathway Analysis upstream regulator analysis was applied to the differentially expressed genes from the Care4Rare Neuron Drug Screen transcriptomic database to identify three distinct signaling networks each perturbed by a different drug and involving a central upstream modulating protein: levothyroxine (DIO3), hydroxyurea (FOXM1), dexamethasone (PPARD). Differential expression of upstream regulator network related genes was next assessed in in vitro and in vivo systems by qPCR, revealing 5× and 10× increases in validation rates, respectively, when compared with our previous experience with individual genes in the dataset not associated with a network. The Ingenuity Pathway Analysis based gene prioritization may increase the predictive value of drug-gene interactions, especially in the context of assessing single-gene modulation in single-replicate experiments.

Transcriptomic RNAseq drug screen in cerebrocortical cultures: toward novel neurogenetic disease therapies.

Rare monogenic diseases affect millions worldwide; although over 4500 rare disease genotypes are known, disease-modifying drugs are available for only 5% of them. The sheer number of these conditions combined with their rarity precludes traditional costly drug discovery programs. An economically viable alternative is to repurpose established drugs for rare diseases. Many genetic diseases result from increased or decreased protein activity and identification of clinically approved drugs which moderate this pathogenic dosage holds therapeutic potential. To identify such agents for neurogenetic diseases, we have generated genome-wide transcriptome profiles of mouse primary cerebrocortical cultures grown in the presence of 218 blood-brain barrier (BBB) penetrant clinic-tested drugs. RNAseq and differential expression analyses were used to generate transcriptomic profiles; therapeutically relevant drug-gene interactions related to rare neurogenetic diseases identified in this fashion were further analyzed by quantitative reverse transcriptase-polymerase chain reaction, western blot and immunofluorescence. We have created a transcriptome-wide searchable database for easy access to the gene expression data resulting from the cerebrocortical drug screen (Neuron Screen) and have mined this data to identify a novel link between thyroid hormone and expression of the peripheral neuropathy associated gene Pmp22. Our results demonstrate the utility of cerebrocortical cultures for transcriptomic drug screening, and the database we have created will foster further discovery of novel links between over 200 clinic-tested BBB penetrant drugs and genes related to diverse neurologic conditions.

A National Spinal Muscular Atrophy Registry for Real-World Evidence.

BACKGROUND: Spinal muscular atrophy (SMA) is a devastating rare disease that affects individuals regardless of ethnicity, gender, and age. The first-approved disease-modifying therapy for SMA, nusinursen, was approved by Health Canada, as well as by American and European regulatory agencies following positive clinical trial outcomes. The trials were conducted in a narrow pediatric population defined by age, severity, and genotype. Broad approval of therapy necessitates close follow-up of potential rare adverse events and effectiveness in the larger real-world population. METHODS: The Canadian Neuromuscular Disease Registry (CNDR) undertook an iterative multi-stakeholder process to expand the existing SMA dataset to capture items relevant to patient outcomes in a post-marketing environment. The CNDR SMA expanded registry is a longitudinal, prospective, observational study of patients with SMA in Canada designed to evaluate the safety and effectiveness of novel therapies and provide practical information unattainable in trials. RESULTS: The consensus expanded dataset includes items that address therapy effectiveness and safety and is collected in a multicenter, prospective, observational study, including SMA patients regardless of therapeutic status. The expanded dataset is aligned with global datasets to facilitate collaboration. Additionally, consensus dataset development aimed to standardize appropriate outcome measures across the network and broader Canadian community. Prospective outcome studies, data use, and analyses are independent of the funding partner. CONCLUSION: Prospective outcome data collected will provide results on safety and effectiveness in a post-therapy approval era. These data are essential to inform improvements in care and access to therapy for all SMA patients.

Direct health-care costs for children diagnosed with genetic diseases are significantly higher than for children with other chronic diseases.

PURPOSE: We aimed to estimate direct health-care costs and physician utilization for a cohort of children diagnosed with genetic diseases. METHODS: Retrospective cohort study using population-based provincial health administrative data for children with genetic diseases (n = 255) compared with three matched cohorts (asthma n = 1275, diabetes n = 255, general population n = 1275). We estimated direct health-care costs and resource use 5 years after diagnosis in five categories: physician billing, same day surgery, emergency, inpatient hospitalizations, and home care. RESULTS: During the postdiagnostic period, annual mean total costs for the genetic disease cohort were significantly higher than all other cohorts. Annual mean total costs for all cohorts were highest in the year after diagnosis with costs for the genetic disease cohort between 4.54 and 19.76 times higher during the 5 years. Inpatient hospitalizations and physician billing accounted for the majority of costs. The genetic disease cohort received more care from specialists, whereas the chronic disease cohorts received more care from general practitioners. CONCLUSION: Direct health-care costs for children with genetic diseases are significantly higher than children with/without a chronic disease, particularly in the year after diagnosis. These findings are important when considering resource allocation and funding prioritization for children with genetic diseases.

Rare-disease genetics in the era of next-generation sequencing: discovery to translation.

Work over the past 25 years has resulted in the identification of genes responsible for ~50% of the estimated 7,000 rare monogenic diseases, and it is predicted that most of the remaining disease-causing genes will be identified by the year 2020, and probably sooner. This marked acceleration is the result of dramatic improvements in DNA-sequencing technologies and the associated analyses. We examine the rapid maturation of rare-disease genetic analysis and successful strategies for gene identification. We highlight the impact of discovering rare-disease-causing genes, from clinical diagnostics to insights gained into biological mechanisms and common diseases. Last, we explore the increasing therapeutic opportunities and challenges that the resulting expansion of the 'atlas' of human genetic pathology will bring.

The Canadian Neuromuscular Disease Registry: Connecting patients to national and international research opportunities.

INTRODUCTION: Patient registries serve an important role in rare disease research, particularly for the recruitment and planning of clinical trials. The Canadian Neuromuscular Disease Registry was established with the primary objective of improving the future for neuromuscular (NM) patients through the enablement and support of research into potential treatments. METHODS: In this report, we discuss design and utilization of the Canadian Neuromuscular Disease Registry with special reference to the paediatric cohort currently enrolled in the registry. RESULTS: As of July 25, 2017, there are 658 paediatric participants enrolled in the registry, 249 are dystrophinopathies (229 are Duchenne muscular dystrophy), 57 are myotonic dystrophy participants, 98 spinal muscular atrophy participants and 65 are limb girdle muscular dystrophy. A total of 175 patients have another NM diagnosis. The registry has facilitated 20 clinical trial inquiries, 5 mail-out survey studies and 5 other studies in the paediatric population. DISCUSSION: The strengths of the registry are discussed. The registry has proven to be an invaluable tool to NM disease research and has increased Canada's visibility as a competitive location for the conduct of clinical trials for NM therapies.

Mouse lysine catabolism to aminoadipate occurs primarily through the saccharopine pathway; implications for pyridoxine dependent epilepsy (PDE).

Lysine is catabolized in mammals through the saccharopine and pipecolate pathways - the former is mainly hepatic and renal, and the latter is believed to play a role in the cerebral lysine oxidation. Both pathways lead to the formation of aminoadipic semialdehyde (AASA) that is then oxidized to aminoadipate (AAA) by antiquitin (ALDH7A1). Mutations in the ALDH7A1 gene result in the accumulation of AASA and its cyclic form, piperideine-6-carboxylate (P6C), which causes pyridoxine-dependent epilepsy (PDE). P6C reacts with pyridoxal 5'-phosphate (PLP) causing its inactivation. Here, we used liquid chromatography-mass spectrometry to investigate lysine catabolism in mice injected with lysine labelled at either its nitrogen epsilon (ε-15N) or nitrogen alpha (α-15N). Analysis of ε-15N and α-15N lysine catabolites in plasma, liver and brain suggested the saccharopine as the main pathway for AAA biosynthesis. Although there was evidence for upstream cerebral pipecolate pathway activity, the resulting pipecolate does not appear to be further oxidized into AASA/P6C/AAA. By far the bulk of lysine degradation and therefore, the primary source of lysine catabolites are hepatic and renal. The results indicate that the saccharopine pathway is primarily responsible for body's production of AASA/P6C. The centrality of the saccharopine pathway in whole body lysine catabolism opens new possibilities of therapeutic targets for PDE. We suggest that inhibition of this pathway upstream of AASA/P6C synthesis may be used to prevent its accumulation benefiting PDE patients. Inhibition of the enzyme aminoadipic semialdehyde synthase, for example, could constitute a new strategy to treat PDE and other inherited diseases of lysine catabolism.

Celecoxib increases SMN and survival in a severe spinal muscular atrophy mouse model via p38 pathway activation.

The loss of functional Survival Motor Neuron (SMN) protein due to mutations or deletion in the SMN1 gene causes autosomal recessive neurodegenerative spinal muscle atrophy (SMA). A potential treatment strategy for SMA is to upregulate the amount of SMN protein originating from the highly homologous SMN2 gene, compensating in part for the absence of the functional SMN1 gene. We have previously shown that in vitro activation of the p38 pathway stabilizes and increases SMN mRNA levels leading to increased SMN protein levels. In this report, we explore the impact of the p38 activating, FDA-approved, blood brain barrier permeating compound celecoxib on SMN levels in vitro and in a mouse model of SMA. We demonstrate a significant induction of SMN protein levels in human and mouse neuronal cells upon treatment with celecoxib. We show that activation of the p38 pathway by low doses celecoxib increases SMN protein in a HuR protein-dependent manner. Furthermore, celecoxib treatment induces SMN expression in brain and spinal cord samples of wild-type mice in vivo. Critically, celecoxib treatment increased SMN levels, improved motor function and enhanced survival in a severe SMA mouse model. Our results identify low dose celecoxib as a potential new member of the SMA therapeutic armamentarium.

Corrigendum: Wastewater-based surveillance identifies start to the pediatric respiratory syncytial virus season in two cities in Ontario, Canada.

[This corrects the article DOI: 10.3389/fpubh.2023.1261165.].

Impact of coagulation on SARS-CoV-2 and PMMoV viral signal in wastewater solids.

Wastewater surveillance (WWS) of SARS-CoV-2 has become a crucial tool for monitoring COVID-19 cases and outbreaks. Previous studies have indicated that SARS-CoV-2 RNA measurement from testing solid-rich primary sludge yields better sensitivity compared to testing wastewater influent. Furthermore, measurement of pepper mild mottle virus (PMMoV) signal in wastewater allows for precise normalization of SARS-CoV-2 viral signal based on solid content, enhancing disease prevalence tracking. However, despite the widespread adoption of WWS, a knowledge gap remains regarding the impact of ferric sulfate coagulation, commonly used in enhanced primary clarification, the initial stage of wastewater treatment where solids are sedimented and removed, on SARS-CoV-2 and PMMoV quantification in wastewater-based epidemiology. This study examines the effects of ferric sulfate addition, along with the associated pH reduction, on the measurement of SARS-CoV-2 and PMMoV viral measurements in wastewater primary clarified sludge through jar testing. Results show that the addition of Fe3+ concentrations in the conventional 0 to 60 mg/L range caused no effect on SARS-CoV-2 N1 and N2 gene region measurements in wastewater solids. However, elevated Fe3+ concentrations were shown to be associated with a statistically significant increase in PMMoV viral measurements in wastewater solids, which consequently resulted in the underestimation of PMMoV-normalized SARS-CoV-2 viral signal measurements (N1 and N2 copies/copies of PMMoV). The observed pH reduction from coagulant addition did not contribute to the increased PMMoV measurements, suggesting that this phenomenon arises from the partitioning of PMMoV viral particles into wastewater solids.