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Human cell line models, including the neuronal precursor line LUHMES, are important for investigating developmental transcriptional dynamics within imprinted regions, particularly the 15q11-q13 Angelman (AS) and Prader-Willi (PWS) syndrome locus. AS results from loss of maternal UBE3A in neurons, where the paternal allele is silenced by a convergent antisense transcript UBE3A-ATS, a lncRNA that terminates at PWAR1 in non-neurons. qRT-PCR analysis confirmed the exclusive and progressive increase in UBE3A-ATS in differentiating LUHMES neurons, validating their use for studying UBE3A silencing. Genome-wide transcriptome analyses revealed changes to 11 834 genes during neuronal differentiation, including the upregulation of most genes within the 15q11-q13 locus. To identify dynamic changes in chromatin loops linked to transcriptional activity, we performed a HiChIP validated by 4C, which identified two neuron-specific CTCF loops between MAGEL2-SNRPN and PWAR1-UBE3A. To determine if allele-specific differentially methylated regions (DMR) may be associated with CTCF loop anchors, whole genome long-read nanopore sequencing was performed. We identified a paternally hypomethylated DMR near the SNRPN upstream loop anchor exclusive to neurons and a paternally hypermethylated DMR near the PWAR1 CTCF anchor exclusive to undifferentiated cells, consistent with increases in neuronal transcription. Additionally, DMRs near CTCF loop anchors were observed in both cell types, indicative of allele-specific differences in chromatin loops regulating imprinted transcription. These results provide an integrated view of the 15q11-q13 epigenetic landscape during LUHMES neuronal differentiation, underscoring the complex interplay of transcription, chromatin looping, and DNA methylation. They also provide insights for future therapeutic approaches for AS and PWS.

BACKGROUND: Angelman syndrome (AS) is a neurodevelopmental disorder associated with severe global developmental delay. However, the ages at which different developmental skills are achieved in these individuals remain unclear. We seek to determine the probability and the age of acquisition of specific developmental milestones and daily living skills in individuals with AS across the different molecular subtypes, viz. class I deletion, class II deletion, uniparental disomy, imprinting defect, and UBE3A variants. METHODS: Caregivers participating in a longitudinal multicenter Angelman Syndrome Natural History Study completed a questionnaire regarding the age at which their children achieved specific developmental milestones and daily living skills. The Cox Proportional Hazard model was applied to analyze differences in the probability of achievement of skills at various ages among five molecular subtypes of AS. RESULTS: Almost all individuals, regardless of molecular subtype, were able to walk with support by five years of age. By age 15, those with a deletion had at least a 50% probability of acquiring 17 out of 30 skills compared to 25 out of 30 skills among those without a deletion. Overall, fine and gross motor skills such as holding and reaching for small objects, sitting, and walking with support were achieved within a fairly narrow range of ages, while toileting, feeding, and hygiene skills tend to have greater variability in the ages at which these skills were achieved. Those without a deletion had a higher probability (25-92%) of achieving daily living skills such as independently toileting and dressing compared to those with a deletion (0-13%). Across all molecular subtypes, there was a low probability of achieving independence in bathing and brushing teeth. CONCLUSION: Individuals with AS without a deletion are more likely to achieve developmental milestones and daily living skills at an earlier age than those with a deletion. Many individuals with AS are unable to achieve daily living skills necessary for independent self-care.

Neurodevelopmental disorders (NDD) encompass a range of conditions marked by abnormal brain development in conjunction with impaired cognitive, emotional and behavioural functions. Transgenic animal models, mainly rodents, traditionally served as key tools for deciphering the molecular mechanisms driving NDD physiopathology and significantly contributed to the development of pharmacological interventions aimed at treating these disorders. However, the efficacy of these treatments in humans has proven to be limited, due in part to the intrinsic constraint of animal models to recapitulate the complex development and structure of the human brain but also to the phenotypic heterogeneity found between affected individuals. Significant advancements in the field of induced pluripotent stem cells (iPSCs) offer a promising avenue for overcoming these challenges. Indeed, the development of advanced differentiation protocols for generating iPSC-derived brain organoids gives an unprecedented opportunity to explore human neurodevelopment. This review provides an overview of how 3D brain organoids have been used to investigate various NDD (i.e. Fragile X syndrome, Rett syndrome, Angelman syndrome, microlissencephaly, Prader-Willi syndrome, Timothy syndrome, tuberous sclerosis syndrome) and elucidate their pathophysiology. We also discuss the benefits and limitations of employing such innovative 3D models compared to animal models and 2D cell culture systems in the realm of personalized medicine. [ABSTRACT FROM AUTHOR]

E3 ubiquitin ligases have been linked to developmental diseases including autism, Angelman syndrome (UBE3A), and Johanson-Blizzard syndrome (JBS) (UBR1). Here, we report variants in the E3 ligase UBR5 in 29 individuals presenting with a neurodevelopmental syndrome that includes developmental delay, autism, intellectual disability, epilepsy, movement disorders, and/or genital anomalies. Their phenotype is distinct from JBS due to the absence of exocrine pancreatic insufficiency and the presence of autism, epilepsy, and, in some probands, a movement disorder. E3 ubiquitin ligases are responsible for transferring ubiquitin to substrate proteins to regulate a variety of cellular functions, including protein degradation, protein-protein interactions, and protein localization. Knocking out ubr-5 in C. elegans resulted in a lower movement score compared to the wild type, supporting a role for UBR5 in neurodevelopment. Using an in vitro autoubiquitination assay and confocal microscopy for the human protein, we found decreased ubiquitination activity and altered cellular localization in several variants found in our cohort compared to the wild type. In conclusion, we found that variants in UBR5 cause a neurodevelopmental syndrome that can be associated with a movement disorder, reinforcing the role of the UBR protein family in a neurodevelopmental disease that differs from previously described ubiquitin-ligase-related syndromes. We also provide evidence for the pathogenic potential loss of UBR5 function with functional experiments in C. elegans and in vitro ubiquitination assays. We identified variants in UBR5 , encoding an E3 ligase, in individuals with a neurodevelopmental syndrome with autism spectrum disorder, epilepsy, movement disorders, and genital anomalies. Functional experiments in C. elegans and human cells support the idea that these UBR5 variants impair its function. [ABSTRACT FROM AUTHOR]

Angelman Syndrome (AS) is a neurodevelopmental disorder caused by the loss of function of ubiquitin‐protein ligase E3A (UBE3A), resulting in marked changes in synaptic plasticity. In AS mice, a dysregulation of Ca2+/calmodulin‐dependent protein kinase II alpha (CaMKIIα) was previously described. This has been convincingly validated through genetic rescue of prominent phenotypes in mouse cross‐breeding experiments. Selective ligands that specifically stabilize the CaMKIIα central association (hub) domain and affect different conformational states in vitro are now available. Two of these ligands, 3‐hydroxycyclopent‐1‐enecarboxylic acid (HOCPCA) and (E)‐2‐(5‐hydroxy‐2‐phenyl‐5,7,8,9‐tetrahydro‐6H‐benzo[7]annulen‐6‐ylidene)acetic acid (Ph‐HTBA), confer neuroprotection after ischemic stroke in mice where CaMKIIα is known to be dysregulated. Here, we sought to investigate whether pharmacological modulation with these prototypical CaMKIIα hub ligands presents a viable approach to alleviate AS symptoms. We performed an in vivo functional evaluation of AS mice treated for a total of 14 days with either HOCPCA or Ph‐HTBA (7 days pre‐treatment and 7 days of behavioural assessment). Both compounds were well‐tolerated but unable to revert robust phenotypes of motor performance, anxiety, repetitive behaviour or seizures in AS mice. Biochemical experiments subsequently assessed CaMKIIα autophosphorylation in AS mouse brain tissue. Taken together our results indicate that pharmacological modulation of CaMKIIα via the selective hub ligands used here is not a viable treatment strategy in AS. [ABSTRACT FROM AUTHOR]

Background: Angelman syndrome (AS), a severe neurodevelopmental disorder resulting from the loss of the maternal UBE3A gene, is marked by changes in the brain's white matter (WM). The extent of WM abnormalities seems to correlate with the severity of clinical symptoms, but these deficits are still poorly characterized or understood. This study provides the first large-scale measurement of WM volume reduction in children with AS. Furthermore, we probed the possibility of underlying WM neuropathology by examining the progression of myelination in an AS mouse model. Methods: We conducted magnetic resonance imaging (MRI) on children with AS (n = 32) and neurotypical controls (n = 99) aged 0.5–12 years. In parallel, we examined myelination in postnatal Ube3a maternal-null mice (Ube3am−/p+; AS model), Ube3a paternal-null mice (Ube3am+/p−), and wildtype controls (Ube3am+/p+) using MRI, immunohistochemistry, western blotting, and electron microscopy. Results: Our data revealed that AS individuals exhibit significant reductions in brain volume by ~ 1 year of age, and by 6–12 years of age WM is reduced by 26% and gray matter by 21%—approximately twice the reductions observed in the adult AS mouse model. Our AS mouse model saw a global delay in the onset of myelination, which normalized within days (likely corresponding to months or years in human development). This myelination delay is caused by the loss of UBE3A in neurons rather than UBE3A haploinsufficiency in oligodendrocytes. Interestingly, ultrastructural analyses did not reveal abnormalities in myelinated or unmyelinated axons. Limitations: It is difficult to extrapolate the timing and duration of the myelination delay observed in AS model mice to individuals with AS. Conclusions: This study reveals WM deficits as a hallmark in children with AS, demonstrating for the first time that these deficits are already apparent at 1 year of age. Parallel studies in a mouse model of AS show these deficits occur alongside the delayed onset of myelination, which results from the loss of neuronal (but not glial) UBE3A, though the causal relationship between these phenotypes remains to be determined. These findings emphasize the potential of WM as both a therapeutic target for interventions and a valuable biomarker for tracking the progression of AS and the effectiveness of potential treatments. [ABSTRACT FROM AUTHOR]

The need for sleep is universal, and the ability to meet this need impacts the quality of life for patients, families, and caregivers. Although substantial progress has been made in treating rare diseases, many patients have unmet medical sleep needs, and current regulatory policy makes it prohibitively difficult to address those needs medically. This opinion reviews the rare disease experience with sleep disorders and explores potential solutions. First, we provide case profiles for the rare diseases Wilson's Disease, Angelman Syndrome, and Prader–Willi Syndrome. These profiles highlight challenges in rare disease diagnosis and barriers to pinpointing disease pathophysiology, including biomarkers that intersect with sleep disorders. Second, we transition to a bird's eye view of sleep disorders and rare diseases by reporting input from a stakeholder discussion with the U.S. Food and Drug Administration regarding abnormal sleep patterns in various rare diseases. Last, in response to the profound unmet medical needs of patients with rare diseases and sleep disorders, we propose adapting and using the clinical trial design known as a "basket trial". In this case, a basket trial would include patients with different rare diseases but the same debilitating symptoms. This research approach has the potential to benefit many rare disease patients who are otherwise left with profound unmet medical needs. [ABSTRACT FROM AUTHOR]

Background: Balanced chromosomal translocations occur in approximately 0.16 to 0.20% of live births. While most carriers are phenotypically normal, they are at risk of generating unbalanced gametes during meiosis, leading to genetic anomalies such as aneuploidies, deletions, duplications, and gene disruptions. These anomalies can result in spontaneous abortions or congenital anomalies, including neurodevelopmental disorders. Complex chromosomal rearrangements (CCRs) involving more than two chromosomes are rare but further increase the probability of producing unbalanced gametes. Neurodevelopmental disorders such as Angelman syndrome (AS) and duplication 15q11q13 syndrome (Dup15q) are associated with such chromosomal abnormalities. Methods: This study describes a family with a de novo maternal balanced double translocation involving chromosomes 13, 19, and 15, resulting in two offspring with unbalanced chromosomal abnormalities. Cytogenetic evaluations were performed using GTG banding, fluorescence in situ hybridization (FISH), and low-pass whole-genome sequencing (LP-WGS). Methylation analysis was conducted using methylation-sensitive high-resolution melting (MS-HRM) to diagnose Angelman syndrome. Results: The cytogenetic and molecular analyses identified an 8.9 Mb duplication in 15q11.2q13.3 in one child, and an 8.9 Mb deletion in the same region in the second child. Both abnormalities affected critical neurodevelopmental genes, such as SNRPN. FISH and MS-HRM confirmed the chromosomal imbalances and the diagnosis of Angelman syndrome in the second child. The maternal balanced translocation was found to be cryptic, contributing to the complex inheritance pattern. Conclusion: This case highlights the importance of using multiple genetic platforms to uncover complex chromosomal rearrangements and their impact on neurodevelopmental disorders. The findings underscore the need for thorough genetic counseling, especially in families with such rare chromosomal alterations, to manage reproductive outcomes and neurodevelopmental risks. [ABSTRACT FROM AUTHOR]

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Abstract Objective We aimed to test whether T‐wave alternans (TWA), which is a marker of susceptibility to ventricular fibrillation, is abnormal in children with Angelman syndrome (AS) compared with typically developing children (TDC), and whether it can be used as a biomarker of AS. Materials and Methods Using surface electrocardiogram (ECG), we calculated TWA in AS and compared it between AS and TDC (Wilcoxon rank sum test). We then performed logistic regression to test TWA ability to distinguish AS from TDC. Results We observed higher TWA in AS than TDC (44 vs. 33 uV, p = 0.009), while heart rate did not differ (p = 0.26), nor its variability (p = 0.72). TWA values enabled discrimination between AS and TDC (p = 0.0008) with accuracy of 81%, positive predictive value of 72%, and negative predictive value of 100%. Interpretation Our findings suggest that ECG in children with AS contains evidence of acquired cardiac abnormality via pathologically increased TWA.

Tropomyosin receptor kinase B (TrkB) signaling plays a pivotal role in dendritic growth and dendritic spine formation to promote learning and memory. The activity-dependent release of brain-derived neurotrophic factor at synapses binds to pre- or postsynaptic TrkB resulting in the strengthening of synapses, reflected by long-term potentiation. Postsynaptically, the association of postsynaptic density protein-95 with TrkB enhances phospholipase Cγ-Ca2+/calmodulin-dependent protein kinase II and phosphatidylinositol 3-kinase-mechanistic target of rapamycin signaling required for long-term potentiation. In this review, we discuss TrkB-postsynaptic density protein-95 coupling as a promising strategy to magnify brain-derived neurotrophic factor signaling towards the development of novel therapeutics for specific neurological disorders. A reduction of TrkB signaling has been observed in neurodegenerative disorders, such as Alzheimer’s disease and Huntington’s disease, and enhancement of postsynaptic density protein-95 association with TrkB signaling could mitigate the observed deficiency of neuronal connectivity in schizophrenia and depression. Treatment with brain-derived neurotrophic factor is problematic, due to poor pharmacokinetics, low brain penetration, and side effects resulting from activation of the p75 neurotrophin receptor or the truncated TrkB.T1 isoform. Although TrkB agonists and antibodies that activate TrkB are being intensively investigated, they cannot distinguish the multiple human TrkB splicing isoforms or cell type-specific functions. Targeting TrkB–postsynaptic density protein-95 coupling provides an alternative approach to specifically boost TrkB signaling at localized synaptic sites versus global stimulation that risks many adverse side effects.

Post-translational modifications (PTMs) of proteins play a significant role in normal protein function but can also be instrumental in disease pathogenesis. One critical yet under-studied PTM in disease is ubiquitination. Ubiquitin chain addition and substrate specificity are determined by a large spectrum of ubiquitin-ligating and -modifying enzymes, E3 ligases, whose expression levels and activities are tightly regulated in a cell-specific manner. While most ubiquitin chains can target proteins for proteasomal degradation, ubiquitination can contribute to other functions within the cell, including protein localization, protein activity, endocytosis, transcription, and autophagy. One E3 ligase, UBE3A, has garnered much attention because of its involvement in learning and memory, as well as its association with neurodevelopmental autism spectrum disorders (ASDs). However, more recent findings have suggested a potential involvement of UBE3A in neurodegenerative proteinopathies, where reduced UBE3A levels can lead to an enhanced rate of aggregate formation and cell death. Here, we review the literature on UBE3A in neurodevelopment, function, and neurodegenerative diseases and demonstrate that UBE3A could play a critical role in disease progression and cognitive function. [ABSTRACT FROM AUTHOR]

Angelman Syndrome (AS) is a neurodevelopmental disorder with severe symptoms and associated comorbidities. It is caused by the inactivity or lack of the UBE3a gene. Symptoms of the syndrome include intellectual disability and developmental delay. The current study investigated sleep disturbances (SD) in children and adolescents with AS, associations between SD and possible predictors of SD. Variables examined included age, gender, newborn and infancy history, challenging behavior, type of therapy received, genetic type of AS, and seizures. The sample included data from 109 participants with a mean age of 8.21, accessed via the Global Angelman Syndrome Registry. Chi-square tests were carried out to assess the associations between the variables and a logistical regression was carried out to assess the possible predictors of SD. Associations were found between SD and certain repetitive behaviors: slapping walls, focal hand movements, and agitation at new situations. From these associations, a regression formed a predictive model for sleep disturbances. The findings of this research demonstrated the importance of investigating the relationship between sleep disturbances and challenging behavior in children and adolescents with AS and the need for further research in this area. • The current study investigated sleep disturbances (SD) in children and adolescents with AS. • The sample included data from 109 participants accessed via the Global Angelman Syndrome Registry. • Associations between sleep disturbances and challenging behavior were examined. • Associations were found between SD and slapping walls, focal hand movements, and agitation at new situations. [ABSTRACT FROM AUTHOR]

Angelman syndrome (AS) and Prader-Willi syndrome (PWS), two distinct neurodevelopmental disorders, result from loss of expression from imprinted genes in the chromosome 15q11-13 locus most commonly caused by a megabase-scale deletion on either the maternal or paternal allele, respectively. Each occurs at an approximate incidence of 1/15,000 to 1/30,000 live births and has a range of debilitating phenotypes. Patient-derived induced pluripotent stem cells (iPSCs) have been valuable tools to understand human-relevant gene regulation at this locus and have contributed to the development of therapeutic approaches for AS. Nonetheless, gaps remain in our understanding of how these deletions contribute to dysregulation and phenotypes of AS and PWS. Variability across cell lines due to donor differences, reprogramming methods, and genetic background make it challenging to fill these gaps in knowledge without substantially increasing the number of cell lines used in the analyses. Isogenic cell lines that differ only by the genetic mutation causing the disease can ease this burden without requiring such a large number of cell lines. Here, we describe the development of isogenic human embryonic stem cell (hESC) lines modeling the most common genetic subtypes of AS and PWS. These lines allow for a facile interrogation of allele-specific gene regulation at the chromosome 15q11-q13 locus. Additionally, these lines are an important resource to identify and test targeted therapeutic approaches for patients with AS and PWS. [ABSTRACT FROM AUTHOR]

Background: Multi-locus imprinting disturbance (MLID) with methylation defects in various differentially methylated regions (DMRs) has recently been identified in approximately 150 cases with imprinting disorders (IDs), and deleterious variants have been found in genes related to methylation maintenance of DMRs, such as those encoding proteins constructing the subcortical maternal complex (SCMC), in a small fraction of patients and/or their mothers. However, integrated methylation analysis for DMRs and sequence analysis for MLID-causative genes in MLID cases and their mothers have been performed only in a single study focusing on Beckwith-Wiedemann syndrome (BWS) and Silver-Russell syndrome (SRS) phenotypes. Results: Of 783 patients with various IDs we have identified to date, we examined a total of 386 patients with confirmed epimutation and 71 patients with epimutation or uniparental disomy. Consequently, we identified MLID in 29 patients with epimutation confirmed by methylation analysis for multiple ID-associated DMRs using pyrosequencing and/or methylation-specific multiple ligation-dependent probe amplification. MLID was detected in approximately 12% of patients with BWS phenotype and approximately 5% of patients with SRS phenotype, but not in patients with Kagami-Ogata syndrome, Prader-Willi syndrome, or Angelman syndrome phenotypes. We next conducted array-based methylation analysis for 78 DMRs and whole-exome sequencing in the 29 patients, revealing hypomethylation-dominant aberrant methylation patterns in various DMRs of all the patients, eight probably deleterious variants in genes for SCMC in the mothers of patients, and one homozygous deleterious variant in ZNF445 in one patient. These variants did not show gene-specific methylation disturbance patterns. Clinically, neurodevelopmental delay and/or intellectual developmental disorder (ND/IDD) was observed in about half of the MLID patients, with no association with the identified methylation disturbance patterns and genetic variants. Notably, seven patients with BWS phenotype were conceived by assisted reproductive technology (ART). Conclusions: The frequency of MLID was 7.5% (29/386) in IDs caused by confirmed epimutation. Furthermore, we revealed diverse patterns of hypomethylation-dominant methylation defects, nine deleterious variants, ND/IDD complications in about half of the MLID patients, and a high frequency of MLID in ART-conceived patients. [ABSTRACT FROM AUTHOR]

Pathognomonic EEG patterns have been described in genetic conditions such as Angelman and Rett syndromes. EEG patterns along the ictal-interictal continuum have been increasingly recognized with the greater availability of continuous EEG monitoring; however, treatment decisions may be difficult with unpredictable clinical implications. Rhythmic High-Amplitude Delta Activity with Superimposed (Poly) Spikes (RHADS) has been described as a particular EEG pattern in POLG1 Alpers Syndrome. The balance between treating subclinical seizures and managing encephalopathy in these patients is challenging. [ABSTRACT FROM AUTHOR]

In the current study, we examined adaptive skills and trajectories over time in 257 individuals with Angelman syndrome (AS) using the Vineland Adaptive Behavior Scales, 2nd Edition. Multilevel linear models were used to examine differences between molecular subtypes over time, from one year to 13 years of age, in the adaptive domains of communication, daily living skills, socialization and motor skills. Individuals with non-deletion subtypes typically demonstrated a higher level of adaptive skills compared to those with deletion subtypes. Statistically significant growth was observed in all adaptive domains through at least early adolescence. Individuals with AS should continue to receive developmental services and educational supports through adolescence and into adulthood given the slow rates of growth being observed across adaptive domains. [ABSTRACT FROM AUTHOR]

Introduction: Long‐read whole genome sequencing like Oxford Nanopore Technology, is increasingly being introduced in clinical settings. With its ability to simultaneously call sequence variation and DNA modifications including 5‐methylcytosine, nanopore is a promising technology to improve diagnostics of imprinting disorders. Methods: Currently, no tools to analyze DNA methylation patterns at known clinically relevant imprinted regions are available. Here we present NanoImprint, which generates an easily interpretable report, based on long‐read nanopore sequencing, to use for identifying clinical relevant abnormalities in methylation levels at 14 imprinted regions and diagnosis of common imprinting disorders. Results and conclusion: NanoImprint outputs a summarizing table and visualization plots displays methylation frequency (%) and chromosomal positions for all regions, with phased data color‐coded for the two alleles. We demonstrate the utility of NanoImprint using three imprinting disorder samples from patients with Beckwith‐Wiedemann syndrome (BWS), Angelman syndrome (AS) and Prader‐Willi syndrome (PWS). NanoImprint script is available from https://github.com/carolinehey/NanoImprint. [ABSTRACT FROM AUTHOR]

BACKGROUND: Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by the absence of a functional UBE3A gene, which causes developmental, behavioral, and medical challenges. While currently untreatable, comprehensive data could help identify appropriate endpoints assessing meaningful improvements in clinical trials. Herein are reported the results from the FREESIAS study assessing the feasibility and utility of in-clinic and at-home measures of key AS symptoms. METHODS: Fifty-five individuals with AS (aged

Angelman Syndrome is a rare neurodevelopmental disorder characterized by developmental delay, lack of speech, seizures, intellectual disability, characteristic behavior, and movement disorders. Clinical gait analysis provides the opportunity for movement quantification to investigate an observed maladaptive change in gait pattern and offers an objective outcome of change. Pressure-sensor-based technology, inertial and activity monitoring, and instrumented gait analysis (IGA) were employed to define motor abnormalities in Angelman syndrome. Temporal-spatial gait parameters of persons with Angelman Syndrome (pwAS) show deficiencies in gait performance through walking speed, step length, step width, and walk ratio. pwAS walk with reduced step lengths, increased step width, and greater variability. Three-dimensional motion kinematics showed increased anterior pelvic tilt, hip flexion, and knee flexion. PwAS have a walk ratio more than two standard deviations below controls. Dynamic electromyography showed prolonged activation of knee extensors, which was associated with a decreased range of motion and the presence of hip flexion contractures. Use of multiple gait tracking modalities revealed that pwAS exhibit a change in gait pattern to a flexed knee gait pattern.  Cross-sectional studies of individuals with AS show a regression toward this maladaptive gait pattern over development in pwAS ages 4-11. PwAS unexpectedly did not have spasticity associated with change in gait pattern. Multiple quantitative measures of motor patterning may offer early biomarkers of gait decline consistent with critical periods of intervention, insight into appropriate management strategies, objective primary outcomes, and early indicators of adverse events.

Abstract Background Angelman syndrome (AS) is a rare neurodevelopmental disease caused by imprinting disorders that impede the production of the ubiquitin E3A ligase protein (UBE3A). AS affects multiple systems, with the main symptoms including epilepsy, psychomotor disorders and speech development disorders. To date, no study has been conducted in the Polish population to verify the condition's diagnosis and treatment process. Results Seventy patients with the median age of 60 months were included into the analysis. 80% of patients were diagnosed with deletion, 19.9% with a mutation of UBE3A gene, 4.3% with paternal uniparental disomy (UPD) and 2.8% with an imprinting defect. The mean age of first symptoms was 5 months, while the mean age of diagnosis was 29 months (earliest in deletion group at 23 months), and the median duration of diagnosis process was 7 months. The average time to a clinical geneticist appointment was 3 months. 37.9% of the patients initially received a different diagnosis. Epileptic seizures were present in 88.6% of the individuals. 98.6% of the studied group were under care of a pediatric neurologist, 47.1% of a gastroenterologist. A ketogenic diet was used in 7.1% of patients. Caregivers identified finding a specialist suitable for AS patients and access to genetic testing as the biggest problems. Conclusions The care of patients with AS in Poland is carried out according to the European and world standards, however there is an impeded access to clinical geneticist, and the knowledge about rare diseases among primary healthcare physicians could be improved. Moreover, access to AS care specialists and coordination of care is limited. There is a need for creation a specialized centers and databases for AS patients.

Abstract Sleep disorders are very common across neurodevelopmental disorders and place a large burden on affected children, adolescents, and their families. Sleep disturbances seem to involve a complex interplay of genetic, neurobiological, and medical/environmental factors in neurodevelopmental disorders. In this review, we discuss animal models of sleep problems and characterize their presence in two single gene disorders, Rett Syndrome, and Angelman Syndrome and two more commonly occurring neurodevelopmental disorders, Down Syndrome, and autism spectrum disorders. We then discuss strategies for novel methods of assessment using wearable sensors more broadly for neurodevelopmental disorders in general, including the importance of analytical validation. An increased understanding of the mechanistic contributions and potential biomarkers of disordered sleep may offer quantifiable targets for interventions that improve overall quality of life for affected individuals and their families.

Abstract Background Angelman syndrome (AS) is a rare neurodevelopmental genetic disorder caused by the loss of function of the ubiquitin ligase E3A (UBE3A) gene, affecting approximately 1:15,000 live births. We have recently shown that mitochondrial function in AS is altered during mid to late embryonic brain development leading to increased oxidative stress and enhanced apoptosis of neural precursor cells. However, the overall alterations of metabolic processes are still unknown. Hence, as a follow-up, we aim to investigate the metabolic profiles of wild-type (WT) and AS littermates and to identify which metabolic processes are aberrant in the brain of AS model mice during embryonic development. Methods We collected brain tissue samples from mice embryos at E16.5 and performed metabolomic analyses using proton nuclear magnetic resonance (1H-NMR) spectroscopy. Multivariate and Univariate analyses were performed to determine the significantly altered metabolites in AS mice. Pathways associated with the altered metabolites were identified using metabolite set enrichment analysis. Results Our analysis showed that overall, the metabolomic fingerprint of AS embryonic brains differed from those of their WT littermates. Moreover, we revealed a significant elevation of distinct metabolites, such as acetate, lactate, and succinate in the AS samples compared to the WT samples. The elevated metabolites were significantly associated with the pyruvate metabolism and glycolytic pathways. Limitations Only 14 metabolites were successfully identified and investigated in the present study. The effect of unidentified metabolites and their unresolved peaks was not determined. Additionally, we conducted the metabolomic study on whole brain tissue samples. Employing high-resolution NMR studies on different brain regions could further expand our knowledge regarding metabolic alterations in the AS brain. Furthermore, increasing the sample size could reveal the involvement of more significantly altered metabolites in the pathophysiology of the AS brain. Conclusions Ube3a loss of function alters bioenergy-related metabolism in the AS brain during embryonic development. Furthermore, these neurochemical changes could be linked to the mitochondrial reactive oxygen species and oxidative stress that occurs during the AS embryonic development.

Angelman syndrome (AS) is a neurogenetic disorder caused by the loss of ubiquitin ligase E3A (UBE3A) gene expression in the brain. The UBE3A gene is paternally imprinted in brain neurons. Clinical features of AS are primarily due to the loss of maternally expressed UBE3A in the brain. A healthy copy of paternal UBE3A is present in the brain but is silenced by a long non-coding antisense transcript (UBE3A-ATS). Here, we demonstrate that an artificial transcription factor (ATF-S1K) can silence Ube3a-ATS in an adult mouse model of Angelman syndrome (AS) and restore endogenous physiological expression of paternal Ube3a. A single injection of adeno-associated virus (AAV) expressing ATF-S1K (AAV-S1K) into the tail vein enabled whole-brain transduction and restored UBE3A protein in neurons to ∼25% of wild-type protein. The ATF-S1K treatment was highly specific to the target site with no detectable inflammatory response 5 weeks after AAV-S1K administration. AAV-S1K treatment of AS mice showed behavioral rescue in exploratory locomotion, a task involving gross and fine motor abilities, similar to low ambulation and velocity in AS patients. The specificity and tolerability of a single injection of AAV-S1K therapy for AS demonstrate the use of ATFs as a promising translational approach for AS.

Background: Angelman syndrome (AS) is a rare neurodevelopmental disease caused by imprinting disorders that impede the production of the ubiquitin E3A ligase protein (UBE3A). AS affects multiple systems, with the main symptoms including epilepsy, psychomotor disorders and speech development disorders. To date, no study has been conducted in the Polish population to verify the condition's diagnosis and treatment process. Results: Seventy patients with the median age of 60 months were included into the analysis. 80% of patients were diagnosed with deletion, 19.9% with a mutation of UBE3A gene, 4.3% with paternal uniparental disomy (UPD) and 2.8% with an imprinting defect. The mean age of first symptoms was 5 months, while the mean age of diagnosis was 29 months (earliest in deletion group at 23 months), and the median duration of diagnosis process was 7 months. The average time to a clinical geneticist appointment was 3 months. 37.9% of the patients initially received a different diagnosis. Epileptic seizures were present in 88.6% of the individuals. 98.6% of the studied group were under care of a pediatric neurologist, 47.1% of a gastroenterologist. A ketogenic diet was used in 7.1% of patients. Caregivers identified finding a specialist suitable for AS patients and access to genetic testing as the biggest problems. Conclusions: The care of patients with AS in Poland is carried out according to the European and world standards, however there is an impeded access to clinical geneticist, and the knowledge about rare diseases among primary healthcare physicians could be improved. Moreover, access to AS care specialists and coordination of care is limited. There is a need for creation a specialized centers and databases for AS patients. [ABSTRACT FROM AUTHOR]

Rare neurological diseases include a vast group of heterogenous syndromes with primary impairment(s) in the peripheral and/or central nervous systems. Such rare disorders may have overlapping phenotypes, despite their distinct genetic etiology. One unique aspect of rare neurological diseases is their potential common association with altered epigenetic mechanisms. Epigenetic mechanisms include regulatory processes that control gene expression and cellular phenotype without changing the composition of the corresponding DNA sequences. Epigenetic factors include three types of proteins, the "readers, writers, and erasers" of DNA and DNA-bound proteins. Thus, epigenetic impairments of many neurological diseases may contribute to their pathology and manifested phenotypes. Here, we aim to provide a comprehensive review on the general etiology of selected rare neurological diseases, that include Rett Syndrome, Prader-Willi Syndrome, Rubinstein-Taybi Syndrome, Huntington's disease, and Angelman syndrome, with respect to their associated aberrant epigenetic mechanisms. [ABSTRACT FROM AUTHOR]