Epigenomic newborn screening for conditions with intellectual disability and autistic features in Australian newborns.

This study describes a protocol to assess a novel workflow called Epi-Genomic Newborn Screening (EpiGNs) on 100,000 infants from the state of Victoria, Australia. The workflow uses a first-tier screening approach called methylation-specific quantitative melt analysis (MS-QMA), followed by second and third tier testing including targeted methylation and copy number variation analyzes with droplet digital PCR, EpiTYPER system and low-coverage whole genome sequencing. EpiGNs utilizes only two 3.2 mm newborn blood spot punches to screen for genetic conditions, including fragile X syndrome, Prader-Willi syndrome, Angelman syndrome, Dup15q syndrome and sex chromosome aneuploidies. The program aims to: identify clinically actionable methylation screening thresholds for the first-tier screen and estimate prevalence for the conditions screened.

[Box: see text].

[Epilepsy in Angelman syndrome and the most common electroencephalographic findings]. / Epilepsia en el síndrome de Angelman y hallazgos electroencefalográficos más frecuentes.

INTRODUCTION: Angelman syndrome is a genetic disorder characterised by severe mental retardation, subtle dysmorphic facial features, a characteristic behavioural phenotype, seizures and abnormalities in video electroencephalograms (video EEG). Angelman syndrome may be associated with genetic mechanisms involving the region of chromosome 15q11-13. Up to 90% of cases have epileptic seizures, usually in the early years of life. Videoelectroencephalography patterns with some typical characteristics associated with Angelman syndrome have been reported, although these are not specific to it, and as such it is also useful for early diagnosis, especially in the first months or years of life. OBJECTIVE: To characterise the videoelectroencephalography findings of 17 patients diagnosed with Angelman syndrome, and compare them with previously published studies. PATIENTS AND METHODS: We conducted a retrospective observational study of 34 video EEGs performed on 17 patients diagnosed with Angelman syndrome at the clinical neurophysiology service of the Puerta de Hierro University Hospital in Madrid between 2019 and 2022. The primary objective was to characterise the videoelectroencephalographic findings and compare them with previously published studies. As secondary objectives, we analysed the patterns proposed by Dan and Boyd, and other demographic, genetic and clinical data. RESULTS: Video EEG supported the clinical suspicion in our study, as baseline brain activity was altered in all the patients. We identified a pattern similar to those defined by Dan and Boyd in 88% of the cases, and the type III pattern was the most common in our series. CONCLUSIONS: These findings confirm that video EEG is highly sensitive for the diagnosis of Angelman syndrome, and very useful as a diagnostic biomarker in the early stages of life.

TITLE: Epilepsia en el síndrome de Angelman y hallazgos electroencefalográficos más frecuentes.Introducción. El síndrome de Angelman es un trastorno genético caracterizado por retraso mental grave, rasgos faciales dismórficos sutiles, fenotipo conductual característico, crisis epilépticas y anomalías en el videoelectroencefalograma (video-EEG). El síndrome de Angelman puede estar asociado a mecanismos genéticos que involucran a la región del cromosoma 15q11-13. Hasta el 90% de los casos tiene crisis epilépticas, más frecuentemente en los primeros años de vida. Se han descrito patrones videoelectroencefalográficos con algunas características típicas asociadas a síndrome de Angelman, aunque no específicas, por lo que también es útil para el diagnóstico temprano, sobre todo en los primeros meses o años de vida. Objetivo. Caracterizar los hallazgos videoelectroencefalográficos de 17 pacientes diagnosticados de síndrome de Angelman y compararlos con estudios publicados previamente. Pacientes y métodos. Hemos realizado un estudio observacional retrospectivo de 34 video-EEG, realizados entre 2019 y 2022, de 17 pacientes con diagnóstico de síndrome de Angelman, llevados a cabo en el servicio de neurofisiología clínica del Hospital Universitario Puerta de Hierro. El objetivo principal fue caracterizar los hallazgos videoelectroencefalográficos y compararlos con estudios publicados previamente. Como objetivos secundarios, hemos analizado los patrones propuestos por Dan y Boyd, y otros datos demográficos, genéticos y clínicos. Resultados. El video-EEG apoyó la sospecha clínica en nuestro estudio, dado que la actividad cerebral de base se encontraba alterada en todos los pacientes. En el 88% de los casos fue posible identificar un patrón semejante a los definidos por Dan y Boyd, y, en nuestra serie, el patrón de tipo III fue el más frecuente. Conclusiones. Estos hallazgos confirman la alta sensibilidad del video-EEG para el diagnóstico de síndrome de Angelman y su gran utilidad como biomarcador diagnóstico en la primera etapa de la vida.

Genotype-phenotype correlation over time in Angelman syndrome: Researching 134 patients.

Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by the loss of function of maternal UBE3A. The major cause of AS is a maternal deletion in 15q11.2-q13, and the minor causes are a UBE3A mutation, uniparental disomy (UPD), and imprinting defect (ID). Previous reports suggest that all patients with AS exhibit developmental delay, movement or balance disorders, behavioral characteristics, and speech impairment. In contrast, a substantial number of AS patients with a UBE3A mutation, UPD, or ID were reported not to show these consistent features and to show age-dependent changes in their features. In this study, we investigated 134 patients with AS, including 57 patients with a UBE3A mutation and 48 patients with UPD or ID. Although developmental delay was present in all patients, 20% of patients with AS caused by UPD or ID did not exhibit movement or balance disorders. Differences were also seen in hypopigmentation and seizures, depending on the causes. Moreover, patients with a UBE3A mutation, UPD, or ID tended to show fewer of the specific phenotypes depending on their age. In particular, in patients with UPD or ID, easily provoked laughter and hyperactivity tended to become more pronounced as they aged. Therefore, the clinical features of AS based on cause and age should be understood, and genetic testing should not be limited to patients with the typical clinical features of AS.

Angelman syndrome in Poland: current diagnosis and therapy status-the caregiver perspective: a questionnaire study.

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.

Evaluation of an In-House Genetic Testing Method for Confirming Prader-Willi and Angelman Syndromes in Sri Lanka.

BACKGROUND: Prader-Willi syndrome (PWS, MIM 176,270) and Angelman syndrome (AS, MIM 105,830) are caused by imprinting defects of chromosome 15q11-13, with loss of maternal gene expression causing AS and paternal gene expression causing PWS. The diagnosis, once established in most cases by using a methylation-specific PCR test, enables appropriate therapeutic interventions and avoids the need for further investigations. Genetic testing for PWS/AS is limited in Sri Lanka (and in other low- and middle-income countries), mainly because parents are unable to pay for testing as these are not funded by the health service. METHODS: Ninety cases (46 female) with clinical features suggesting PWS (n = 37) and AS (n = 53), referred by a pediatric endocrinologist and a pediatric neurologist, were recruited. Clinical information and blood samples were obtained following informed consent. DNA was extracted and methylation-specific PCR (MS-PCR) was performed following bisulfite modification of DNA by using an in-house method and a kit. Results were validated using known positive controls. Parent-child trio DNA samples were used in cases with confirmed PWS and AS to determine if the disease was due to a deletion or uniparental disomy. The cost of the MS-PCR testing of the two modification methods and the microsatellite analysis was determined. RESULTS: Among the suspected PWS cases, 19/37 were positive, while 5/53 of the suspected AS cases were positive. The lower identification rate of AS is probably related to the overlap of clinical features of this condition with other disorders. The kit-based modification method was more reliable, less time-consuming, and cost-effective in our laboratory. CONCLUSIONS: The kit-based modification followed by MS-PCR described in this study enables more affordable genetic testing of suspected PWS/AS cases, and this is likely to improve patient care by targeting appropriate therapy for the affected cases. Parental genetic counselling is made possible regarding the low recurrence risk, especially where a deletion or uniparental disomy is confirmed. In MS-PCR, negative cases with a strong clinical suspicion of AS, UBE3A mutation testing is required. In addition, imprinting center mutation/deletion testing may also be needed in strongly clinically suspected, MS-PCR negative PWS and AS cases.

A case of an Angelman-syndrome caused by an intragenic duplication of UBE3A uncovered by adaptive nanopore sequencing.

Adaptive nanopore sequencing as a diagnostic method for imprinting disorders and episignature analysis revealed an intragenic duplication of Exon 6 and 7 in UBE3A (NM_000462.5) in a patient with relatively mild Angelman-like syndrome. In an all-in-one nanopore sequencing analysis DNA hypomethylation of the SNURF:TSS-DMR, known contributing deletions on the maternal allele and point mutations in UBE3A could be ruled out as disease drivers. In contrast, breakpoints and orientation of the tandem duplication could clearly be defined. Segregation analysis in the family showed that the duplication derived de novo in the maternal grandfather. Our study shows the benefits of an all-in-one nanopore sequencing approach for the diagnostics of Angelman syndrome and other imprinting disorders.

Understanding reliability of the observer-reported communication ability measure within Angelman syndrome through the lens of generalizability theory.

AIMS: Caregivers rate improved communication ability as one of the most desired outcomes for successful interventions for individuals with Angelman syndrome (AS). When measuring communication ability in clinical trials, the reliability of such measures is critical for detecting significant changes over time. This study examined the reliability of the Observed-Reported Communication Ability (ORCA) measure completed by caregivers of individuals with AS. METHODS: The ORCA measure was completed by 249 caregivers with 170 caregivers completing the ORCA measure again after 5-12 days. Generalizability theory was used to examine the following sources of measurement error in ORCA scores: concepts, subdomains, assessment points, and the interactions among those facets and the object of measurement: communication ability. Three generalizability studies were conducted to understand the reliability of the ORCA measure for different measurement designs. Decision studies were carried out to demonstrate the optimization of measurement procedures of the ORCA measure. RESULTS: G and Phi coefficients of the original measurement design exceeded the 0.80 threshold considered sufficiently reliable to make relative and absolute decisions about the communication ability of individuals with AS based on their caregivers' observed scores. The optimization procedures indicated that increasing the number of communication concepts and/or assessment points leads to more reliable estimates of communication. CONCLUSION: The ORCA measure was able to reliably distinguish different levels of communication ability among individuals with AS. Multiple assessment points and or more concepts would provide more precise estimates of an individual's communication ability but at the cost of survey fatigue.

Establishing a Standardized DNA Extraction Method Using NaCl from Oral Mucosa Cells for Its Application in Imprinting Diseases Such as Prader-Willi and Angelman Syndromes: A Preliminary Investigation.

BACKGROUND: Diagnosing imprinting defects in neonates and young children presents challenges, often necessitating molecular analysis for a conclusive diagnosis. The isolation of genetic material from oral swabs becomes crucial, especially in settings where blood sample collection is impractical or for vulnerable populations like newborns, who possess limited blood volumes and are often too fragile for invasive procedures. Oral swab samples emerge as an excellent source of DNA, effectively overcoming obstacles associated with rare diseases. METHODS: In our study, we specifically addressed the determination of the quality and quantity of DNA extracted from oral swab samples using NaCl procedures. RESULTS: We compared these results with extractions performed using a commercial kit. Subsequently, the obtained material underwent MS-HRM analysis for loci associated with imprinting diseases such as Prader-Willi and Angelman syndromes. CONCLUSIONS: Our study emphasizes the significance of oral swab samples as a reliable source for obtaining DNA for MS-HRM analysis. NaCl extraction stands out as a practical and cost-effective method for genetic studies, contributing to a molecular diagnosis that proves particularly beneficial for patients facing delays in characterization, ultimately influencing their treatment.

NanoImprint: A DNA methylation tool for clinical interpretation and diagnosis of common imprinting disorders using nanopore long-read sequencing.

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.

Specificity of Early Childhood Hyperphagia Profiles in Neurogenetic Conditions.

Hyperphagia is highly penetrant in Prader-Willi syndrome (PWS) and has increasingly been reported in other neurogenetic conditions (NGC). The Hyperphagia Questionnaire (HQ) was completed by caregivers of 4-8-year-olds with PWS (n = 17), Angelman syndrome (AS; n = 22), Williams syndrome (WS; n = 25), or low-risk controls (LRC; n = 35). All NGC groups were significantly elevated in HQ Total and Behavior scores compared to LRC. Only AS and WS were significantly elevated in the Drive domain, and only PWS in the Severity domain. After controlling for externalizing behavior, HQ Total scores were higher for PWS relative to other groups. Hyperphagic symptoms may not differentiate PWS from other NGCs in early childhood. However, hyperphagic phenotypes may be most severe in PWS. Further investigation of these profiles may inform etiology and syndrome-specific treatments.

Exploring an objective measure of overactivity in children with rare genetic syndromes.

BACKGROUND: Overactivity is prevalent in several rare genetic neurodevelopmental syndromes, including Smith-Magenis syndrome, Angelman syndrome, and tuberous sclerosis complex, although has been predominantly assessed using questionnaire techniques. Threats to the precision and validity of questionnaire data may undermine existing insights into this behaviour. Previous research indicates objective measures, namely actigraphy, can effectively differentiate non-overactive children from those with attention-deficit hyperactivity disorder. This study is the first to examine the sensitivity of actigraphy to overactivity across rare genetic syndromes associated with intellectual disability, through comparisons with typically-developing peers and questionnaire overactivity estimates. METHODS: A secondary analysis of actigraphy data and overactivity estimates from The Activity Questionnaire (TAQ) was conducted for children aged 4-15 years with Smith-Magenis syndrome (N=20), Angelman syndrome (N=26), tuberous sclerosis complex (N=16), and typically-developing children (N=61). Actigraphy data were summarized using the M10 non-parametric circadian rhythm variable, and 24-hour activity profiles were modelled via functional linear modelling. Associations between actigraphy data and TAQ overactivity estimates were explored. Differences in actigraphy-defined activity were also examined between syndrome and typically-developing groups, and between children with high and low TAQ overactivity scores within syndromes. RESULTS: M10 and TAQ overactivity scores were strongly positively correlated for children with Angelman syndrome and Smith-Magenis syndrome. M10 did not substantially differ between the syndrome and typically-developing groups. Higher early morning activity and lower evening activity was observed across all syndrome groups relative to typically-developing peers. High and low TAQ group comparisons revealed syndrome-specific profiles of overactivity, persisting throughout the day in Angelman syndrome, occurring during the early morning and early afternoon in Smith-Magenis syndrome, and manifesting briefly in the evening in tuberous sclerosis complex. DISCUSSION: These findings provide some support for the sensitivity of actigraphy to overactivity in children with rare genetic syndromes, and offer syndrome-specific temporal descriptions of overactivity. The findings advance existing descriptions of overactivity, provided by questionnaire techniques, in children with rare genetic syndromes and have implications for the measurement of overactivity. Future studies should examine the impact of syndrome-related characteristics on actigraphy-defined activity and overactivity estimates from actigraphy and questionnaire techniques.

Outcome measures in Angelman syndrome.

BACKGROUND: Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by severe intellectual disability, little to no expressive speech, visual and motor problems, emotional/behavioral challenges, and a tendency towards hyperphagia and weight gain. The characteristics of AS make it difficult to measure these children's functioning with standard clinical tests. Feasible outcome measures are needed to measure current functioning and change over time, in clinical practice and clinical trials. AIM: Our first aim is to assess the feasibility of several functional tests. We target domains of neurocognitive functioning and physical growth using the following measurement methods: eye-tracking, functional Near-Infrared Spectroscopy (fNIRS), indirect calorimetry, bio-impedance analysis (BIA), and BOD POD (air-displacement plethysmography). Our second aim is to explore the results of the above measures, in order to better understand the AS phenotype. METHODS: The study sample consisted of 28 children with AS aged 2-18 years. We defined an outcome measure as feasible when (1) at least 70% of participants successfully finished the measurement and (2) at least 60% of those participants had acceptable data quality. Adaptations to the test procedure and reasons for early termination were noted. Parents rated acceptability and importance and were invited to make recommendations to increase feasibility. The results of the measures were explored. RESULTS: Outcome measures obtained with eye-tracking and BOD POD met the definition of feasibility, while fNIRS, indirect calorimetry, and BIA did not. The most important reasons for early termination of measurements were showing signs of protest, inability to sit still and poor/no calibration (eye-tracking specific). Post-calibration was often applied to obtain valid eye-tracking results. Parents rated the BOD POD als most acceptable and fNIRS as least acceptable for their child. All outcome measures were rated to be important. Exploratory results indicated longer reaction times to high salient visual stimuli (eye-tracking) as well as high body fat percentage (BOD POD). CONCLUSIONS: Eye-tracking and BOD POD are feasible measurement methods for children with AS. Eye-tracking was successfully used to assess visual orienting functions in the current study and (with some practical adaptations) can potentially be used to assess other outcomes as well. BOD POD was successfully used to examine body composition. TRIAL REGISTRATION: Registered d.d. 23-04-2020 under number 'NL8550' in the Dutch Trial Register: https://onderzoekmetmensen.nl/en/trial/23075.

Undiagnosed rare disease clinic identifies a novel UBE3A variant in two sisters with Angelman syndrome: The end of a diagnostic odyssey.

Angelman syndrome (AS, MIM #105830) is a neurodevelopmental disorder characterized by severe intellectual disability, profound developmental delay, movement or balance problems, an excessively cheerful disposition, and seizures. AS results from inadequate expression of the maternal UBE3A gene (MIM #601623), which encodes an E3 ligase in the ubiquitin-proteasome pathway. Here we present the case of two sisters with features consistent with AS who had negative methylation analyses. An autism/intellectual disability expanded panel revealed a maternally inherited novel UBE3A (NM_001354506.2) variant c.2443C>T p.(Pro815Ser) in both patients that was initially classified as a variant of uncertain significance. The patients were enrolled in Indiana University's Undiagnosed Rare Disease Clinic (URDC) to further investigate the variant. Additional data, including deep phenotyping, familial segregation analysis, and in silico studies, suggest that the variant is likely pathogenic. 3D modeling studies based on the available crystal structure revealed that the Pro815Ser variant can introduce more flexibility into the protein and alter its enzymatic activity. Recent literature confirms the pathogenic nature of the variant. Reanalysis of the UBE3A variant has heightened existing knowledge of AS and has offered this family an end to their diagnostic odyssey.

Relationship between strabismus associated with Angelman syndrome and orbital anomaly.

PURPOSE: To investigate the relationship between the details of strabismus and orbital abnormalities determined by ocular motility tests and orbital imaging examinations in 9 cases with Angelman syndrome (AS). STUDY DESIGN: A retrospective, clinical report. METHODS: The 9 AS cases (mean age at initial visit: 4.6 ± 8.0 years) were confirmed by genetic diagnosis of the chromosome 15q11-13 region. In all cases, axial imaging of the orbit in the transverse plane of the horizontal extraocular muscles was obtained. The opening angle between both lateral walls of the orbit (greater wing of sphenoid) was measured as the biorbital angle, and compared with the 95% confidence interval of the orbital angle in normal children. RESULTS: All cases had exotropia with means of the distance and near of angle 32.2 prism diopters (Δ) ± 9.7Δ and 32.8Δ ± 8.3Δ. The mean of the biorbital angle was 107.7° ± 7.6°, greater than the biorbital angle of 94.3° ± 5.1° previously reported in 129 normal children (P < 0.0001, t-test). Except for one biorbital angle of 93° in the 25-year-old patient, all the biorbital angles in the 8 children were larger than the upper 95% confidence interval in normal children. Astigmatic and hyperopic ametropic amblyopia were detected in 3 cases and 1 case, respectively. CONCLUSIONS: The frequency of exotropia in AS is higher than previously reported, with our results strongly suggesting that the enlarged biorbital angle is related to the pathogenesis of exotropia in AS.

Age of diagnosis for children with chromosome 15q syndromes.

OBJECTIVE: The objective of this study was to identify the age of diagnosis for children with one of three neurogenetic conditions resulting from changes in chromosome 15 (Angelman syndrome [AS], Prader-Willi syndrome [PWS], and duplication 15q syndrome [Dup15q]). METHODS: Data about the diagnostic process for each condition were contributed by the advocacy organizations. Median and interquartile ranges were calculated for each condition by molecular subtype and year. Comparison tests were run to explore group differences. RESULTS: The median age of diagnosis was 1.8 years for both AS and Dup15q. PWS was diagnosed significantly younger at a median age of 1 month. Deletion subtypes for both PWS and AS were diagnosed earlier than nondeletion subtypes, and children with isodicentric duplications in Dup15q were diagnosed earlier than those with interstitial duplications. CONCLUSION: Understanding variability in the age of diagnosis for chromosome 15 disorders is an important step in reducing the diagnostic odyssey and improving access to interventions for these populations. Results from this study provide a baseline by which to evaluate efforts to reduce the age of diagnosis for individuals with these conditions.

An adapted clinical global Impression of improvement for use in Angelman syndrome: Validation analyses utilizing data from the NEPTUNE study.

PURPOSE: Angelman Syndrome (AS) is a rare, severe neurogenetic disorder that causes symptoms such as intellectual disability and motor impairments and is typically diagnosed in early childhood. The complexity and heterogeneity of AS confound characterization of disease severity and pose unique challenges when determining an individual's response to treatment. There is therefore a substantial unmet need for rating scales specifically designed for complex conditions such as AS. To address this, the Clinical Global Impressions (CGI) scale, which has components for both symptom severity (CGI-S) and improvement (CGI-I) was specifically adapted to measure severity (CGI-S-AS) and improvement (CGI-I-AS) in AS. METHODS: The modified CGI-S/I-AS was used in the NEPTUNE trial of gaboxadol for the treatment of AS. Here we report on the validation of the CGI-I-AS using data from NEPTUNE and discuss insights for its potential use in future trials. RESULTS: Improvements in the CGI-I-AS rating tended to be consistent with changes on other relevant rating scales. Sleep-related symptoms were particularly well represented, while communication-related symptoms were not. CONCLUSIONS: Our validation analysis of the CGI-I-AS demonstrates its usefulness along with possible areas of improvement. The CGI-I-AS is a potential tool for use in other trials of AS drug candidates, and the process for its development can serve as a road map for the development of assessment tools for other neuropsychiatric disorders with similar complexities and heterogeneity.

Quantitative measures of motor development in Angelman syndrome.

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.

H4C5 missense variant leads to a neurodevelopmental phenotype overlapping with Angelman syndrome.

Recurrent de novo missense variants in H4 histone genes have recently been associated with a novel neurodevelopmental syndrome that is characterized by intellectual disability and developmental delay as well as more variable findings that include short stature, microcephaly, and facial dysmorphisms. A 4-year-old male with autism, developmental delay, microcephaly, and a happy demeanor underwent evaluation through the Undiagnosed Disease Network. He was clinically suspected to have Angelman syndrome; however, molecular testing was negative. Genome sequencing identified the H4 histone gene variant H4C5 NM_003545.4: c.295T>C, p.Tyr99His, which parental testing confirmed to be de novo. The variant met criteria for a likely pathogenic classification and is one of the seven known disease-causing missense variants in H4C5. A comparison of our proband's findings to the initial description of the H4-associated neurodevelopmental syndrome demonstrates that his phenotype closely matches the spectrum of those reported among the 29 affected individuals. As such, this report corroborates the delineation of neurodevelopmental syndrome caused by de novo missense H4 gene variants. Moreover, it suggests that cases of clinically suspected Angelman syndrome without molecular confirmation should undergo exome or genome sequencing, as novel neurodevelopmental syndromes with phenotypes overlapping with Angelman continue to be discovered.

[Angelman syndrome in adulthood]. / Síndrome de Angelman en el adulto.

INTRODUCTION: Angelman syndrome (AS) is widely described in childhood, but few studies have been conducted in adulthood and most of them report a small number of patients or specific conditions, such as epilepsy or sleep. AIM: The aim of this study is to describe AS in adulthood in our centre, the special needs it requires, and the medical and social support to improve care and to provide a better transition from the paediatric service to units for adults. PATIENTS AND METHODS: We collected patients with genetically confirmed AS, and described demographic, medical and social data by reviewing medical records, telephone interviews with the primary caregiver and three standardised sleep, dependency and quality of life scales. RESULTS: Thirty patients with a median age of 22.7 years were included: 22 were deletions, 27 had a history of epilepsy and 13 were on treatment involving at least two antiepileptic drugs. The most frequent comorbidities after epilepsy were psychiatric symptoms, scoliosis, overweight, constipation and ophthalmological problems. Forty per cent required hospital admissions in adulthood, five were institutionalised and 24 received non-medical therapies. The doctor in charge was the neurologist in most cases, followed by the neuropaediatrician. CONCLUSIONS: Studies that examine the natural history beyond childhood are warranted. This is the first Spanish review of adults with AS that covers a broad spectrum of social and medical conditions of these patients.

TITLE: Síndrome de Angelman en el adulto.Introducción. El síndrome de Angelman (SA) está ampliamente descrito en la infancia, pero existen escasos estudios en edad adulta y la mayoría recoge un pequeño número de pacientes o condiciones específicas, como epilepsia o sueño. Objetivo. El objetivo de este estudio es describir el SA en la edad adulta en nuestro centro, sus necesidades especiales, y el soporte médico y social para mejorar la atención y ofrecer una mejor transición del servicio de pediatría a las unidades de adultos. Pacientes y métodos. Se recogen pacientes con SA genéticamente confirmado, y describimos datos demográficos, médicos y sociales mediante la revisión de historias clínicas, entrevistas telefónicas con el cuidador principal y tres escalas estandarizadas de sueño, dependencia y calidad de vida. Resultados. Se incluye a 30 pacientes con una mediana de edad de 22,7 años: 22 son deleciones, 27 presentan antecedente de epilepsia y 13 están en tratamiento con, al menos, dos fármacos antiepilépticos. Las comorbilidades más frecuentes después de la epilepsia fueron los síntomas psiquiátricos, la escoliosis, el sobrepeso, el estreñimiento y problemas oftalmológicos. El 40% precisó ingresos hospitalarios en la edad adulta, cinco están institucionalizados y 24 reciben terapias no médicas. El médico a cargo es el neurólogo en la mayoría, seguido del neuropediatra. Conclusiones. Es necesario realizar estudios de historia natural más allá de la infancia. Ésta es la primera revisión española de adultos con SA que recoge un amplio espectro de condiciones sociales y médicas de estos pacientes.