A long-term population-based clinical and morbidity profile of Angelman syndrome in Western Australia: 1953-2003

Child characteristics associated with child quality of life and parenting stress in Angelman syndrome

BACKGROUND

Angelman syndrome (AS) is a rare neurodevelopmental disorder characterised by severe intellectual disability, movement disorder, epilepsy, sleeping problems, and behavioural issues. Little is known on child health-related quality of life (HRQoL) in AS. AS family studies have reported elevated parenting stress and a high impact of the child's syndrome on the parent. It is unclear which factors influence child HRQoL and parenting stress/impact in AS.

METHODS

We collected data prospectively through standardised clinical assessments of children with AS at the ENCORE Expertise centre for Angelman Syndrome at the Erasmus MC Sophia Children's Hospital. A linear regression analysis was conducted for the following outcome variables: (1) child HRQoL (Infant and Toddler Quality of Life Questionnaire); (2) the impact of the child's syndrome on the parent (Infant and Toddler Quality of Life Questionnaire); and (3) parenting stress (Parenting Stress Index). Predictor variables were child genotype, epilepsy, sleeping problems (Sleep Disturbance Scale for Children), cognitive developmental level (Bayley Cognition Scale), autistic features (Autism Diagnostic Observation Schedule) and emotional/behavioural problems (Child Behaviour Checklist). Covariates were sex, age and socio-economic status.

RESULTS

The study sample consisted of 73 children with AS, mean age = 9.1 years, range = 2-18 years. Emotional/behavioural problems were the strongest significant predictor of lowered child HRQoL. Internalising problems were driving this effect. In addition, having the deletion genotype and higher age was related to lower child HRQoL. Sleeping problems were related to a higher impact of the child's syndrome on the parent. Finally, emotional/behavioural problems were associated with higher parenting stress. Cognitive developmental level, autistic features and epilepsy were not a significant predictor of child HRQoL and parenting stress/impact.

CONCLUSIONS

These results suggest that interventions aimed at increasing child HRQoL and decreasing parenting stress/impact in AS should focus on child emotional/behavioural problems and sleeping problems, using a family-centred approach.

Health-related quality of life and medication use among individuals with Angelman syndrome

PURPOSE

The primary goal of this analysis is to describe the health-related quality of life (HRQoL), medical history, and medication use among adolescents and adults individuals with Angelman syndrome (AS).

METHODS

The analysis uses baseline data collected during the STARS study, a double-blind placebo controlled trial of gaboxadol (OV101) in adolescents and adults with AS. The HRQoL was estimated using EuroQoL 5-Dimension 5-Level (EQ-5D) health questionnaire proxy 1 version, which was completed by the caregivers. EQ-5D consists of two parts, a 5-dimension descriptive and a visual analogue scale (VAS) component. The utility score derived from EQ-5D ranges from 0 to 1 (perfect health) and VAS ranges from 0 to 100 (perfect health).

RESULTS

87 individuals with AS were included in the present analysis. The mean utility score was 0.44 ± 0.20 and VAS score was 84 ± 1.5. The EQ-5D data indicated that the self-care, mobility and daily activities were most impacted. All adolescents (100%) and most adults (93%) had at least moderate problems with self-care activities, such as washing or dressing themselves. More than half (55%) of the adolescents and adults had at least moderate issues with mobility and usual activities. Approximately, 30% of adolescents and adults had moderate to extreme problems with anxiety/depression. High baseline concomitant use of medications was observed across both age groups with an average of 5 medications being used per person.

CONCLUSION

This study highlights the impact of AS on HRQoL and medication utilization among adolescents and adults individuals with AS.

Estimating the impact of Angelman syndrome on parental productivity in Australia using productivity-adjusted life years

BACKGROUND

Angelman syndrome (AS) is a rare genetic condition characterized by global developmental delay, including severe intellectual disability. The parents of persons with AS experience increased stress, anxiety, and depression. This impacts parents' career choices and productivity.

OBJECTIVE

To estimate, for the first time, the total productivity lost by the parents of persons with AS over a 10-year period in Australia and the corresponding cost to society.

METHODS

A cost-of-illness model with simulated follow-up over a 10-year period was developed, with 2019 as the baseline year, facilitated by a Markov chain of life tables. The prevalence of persons with AS and their parents, the productivity-adjusted life years (PALYs) lost by parents, and the cost to society were estimated. Key data were obtained from a prospective cohort of AS families, peer-reviewed literature, and publicly available sources.

RESULTS

The base-case productivity burden borne by the estimated 330 living parents of the 428 prevalent persons with AS totaled AUD$45.30 million, corresponding to a loss of 38.42% of PALYs per parent.

CONCLUSIONS

Caring for a child with AS has a significant impact on the productivity of affected parents, with a large associated impact on the broader Australian economy.

An Analysis of Phenotype and Genotype in a Large Cohort of Chinese Children with Angelman Syndrome

Angelman syndrome (AS) is a neurodevelopmental genetic disorder, but there has been limited analysis of a large cohort of Chinese children with Angelman syndrome. This study aims to assess the phenotype and genotype of Chinese children with Angelman syndrome. We retrospectively analyzed data through a detailed online survey combined with an on-site study. Furthermore, phenotype analysis stratified by deletion and non-deletion groups was carried out. The responses of family members of 695 individuals with AS revealed that 577 patients (83.02%) had maternal deletions, 65 patients (9.35%) carried UBE3A mutations, 31 (4.46%) patients had UPD15pat (one patient with UPD15pat constituted by a mosaic), 10 patients (1.44%) had imprinting defects and 12 (1.58%) patients only showed abnormal methylation without further detection. We identified 50 different pathogenic variants in this cohort, although 18 of these variants were unreported. Recurrent variant c.2507_2510del (p.K836Rfs*4) was found in 7 patients. In the deletion group, patients were diagnosed at an earlier age, had a more severe clinical phenotype, a higher rate of epilepsy with more multiple seizure types, and more frequently combined medication. Strabismus and sleep disturbances were both common in deletion and non-deletion groups. The top three resources invested in caring for AS children are: daily involvement in patient care, rehabilitation cost, and anti-epileptic treatment. Our study showed the genetic composition of Chinese children with 83.02% of maternal deletions, and the mutation spectrum for UBE3A variants was expanded. Developmental outcomes are associated with genotype, and this was confirmed by deletion patients having a worse clinical phenotype and complex epilepsy.

Prevalence and incidence of physical health conditions in people with intellectual disability - a systematic review

OBJECTIVE

To synthesize evidence on the prevalence and incidence of physical health conditions in people with intellectual disability (ID).

METHODS

We searched Medline, PsycInfo, and Embase for eligible studies and extracted the prevalence, incidence, and risk of physical health conditions in people with ID.

RESULTS

Of 131 eligible studies, we synthesized results from 77 moderate- to high-quality studies, which was mainly limited to high-income countries. The highest prevalence estimates were observed for epilepsy, ear and eye disorders, cerebral palsy, obesity, osteoporosis, congenital heart defects, and thyroid disorders. Some conditions were more common in people with a genetic syndrome. Compared with the general population, many health conditions occur more frequently among people with ID, including asthma and diabetes, while some conditions such as non-congenital circulatory diseases and solid cancers occur at the same or lower rate. The latter associations may reflect under-detection.

CONCLUSIONS

People with ID have a health profile more complex than previously known. There is a pressing need for targeted, evidence-informed population health initiatives including preventative programs for this population.

The Cost of Raising Individuals with Fragile X or Chromosome 15 Imprinting Disorders in Australia

The study characterised differences in costs associated with raising a child between four rare disorders and examined the associations between these costs with clinical severity. Caregivers of 108 individuals with Prader-Willi, Angelman (AS), Chromosome 15q Duplication and fragile X (FXS) syndromes completed a modified Client Services Receipt Inventory and participants completed intellectual/developmental functioning and autism assessments. AS incurred the highest yearly costs per individual ($AUD96,994), while FXS had the lowest costs ($AUD33,221). Intellectual functioning negatively predicted total costs, after controlling for diagnosis. The effect of intellectual functioning on total costs for those with AS was significantly different to the other syndromes. The study highlights the significant costs associated with these syndromes, particularly AS, linked with severity of intellectual functioning.

An observational study of pediatric healthcare burden in Angelman syndrome: results from a real-world study

Background

The objective of this study is to describe variations in the healthcare resource utilization (HRU) among individuals with Angelman syndrome (AS) over the first 12 years of life. Data for this study were drawn from the AS Natural History study (ASNHS), which is an observational study on the developmental progress, behavior, and medical morbidity of individuals with AS conducted over eight years. Caregiver-reported information on hospitalization, surgery, and medication utilization was used to assess HRU. Repeated measures mixed effect models were used to assess the relationship between age and probability of hospitalization, surgery, and prescription medication utilization.

Results

Mean age at study enrollment was 6 years of age and both sexes were equally represented. The mean number of visits per participant was three. Results from this study suggest that individuals with AS have a high HRU burden. Hospitalization and surgery burden were highest in the first year of life. Use of medications for seizures and sleep disturbance increased over time.

Conclusions

The study highlights the significant healthcare burden among individuals with AS. Future studies that estimate cost and caregiver burden associated with AS are needed to assess the lifelong economic impact of AS on families and healthcare system.

A retrospective analysis of the prevalence of imprinting disorders in Estonia from 1998 to 2016

Imprinting disorders (ImpDis) represent a small group of rare congenital diseases primarily affecting growth, development, and the hormonal and metabolic systems. The aim of present study was to identify the prevalence of the ImpDis in Estonia, to describe trends in the live birth prevalence of these disorders between 1998 and 2016, and to compare the results with previously published data. We retrospectively reviewed the records of all Estonian patients since 1998 with both molecularly and clinically diagnosed ImpDis. A prospective study was also conducted, in which all patients with clinical suspicion for an ImpDis were molecularly analyzed. Eighty-seven individuals with ImpDis were identified. Twenty-seven (31%) of them had Prader-Willi syndrome (PWS), 15 (17%) had Angelman syndrome (AS), 15 (17%) had Silver-Russell syndrome (SRS), 12 (14%) had Beckwith-Wiedemann syndrome (BWS), 10 (11%) had pseudo- or pseudopseudohypoparathyroidism, four had central precocious puberty, two had Temple syndrome, one had transient neonatal diabetes mellitus, and one had myoclonus-dystonia syndrome. One third of SRS and BWS cases fulfilled the diagnostic criteria for these disorders, but tested negative for genetic abnormalities. Seventy-six individuals were alive as of January 1, 2018, indicating the total prevalence of ImpDis in Estonia is 5.8/100,000 (95% CI 4.6/100,000-7.2/100,000). The minimum live birth prevalence of all ImpDis in Estonia in 2004-2016 was 1/3,462, PWS 1/13,599, AS 1/27,198, BWS 1/21,154, SRS 1/15,866, and PHP/PPHP 1/27,198. Our results are only partially consistent with previously published data. The worldwide prevalence of SRS and GNAS-gene-related ImpDis is likely underestimated and may be at least three times higher than expected.

Healthcare burden among individuals with Angelman syndrome: Findings from the Angelman Syndrome Natural History Study

Background

The objective of this study is to describe healthcare resource utilization (HRU) and supportive therapy utilization (STU) among individuals with Angelman syndrome (AS), and to compare such usage by molecular etiology.

Methods

Participants were categorized into deletion and non‐deletion genotypes. Statistical differences were assessed using an independent samples t test.

Results

Data were available on 302 individuals. Mean age of participants was 5.5 years, 92% of whom were less than 13 years, and 71% had the deletion etiology. About 68% of participants had at least one hospitalization since birth to enrollment in the study; the average number of hospitalizations during that time period was 2.3 and average length of stay was 4.5 days. The most common reasons for hospitalization were seizures, lower respiratory infections, and surgery. The most common reasons for surgery were myringotomy, strabismus surgery, tonsillectomy or adenoidectomy, and gastrostomy tube insertion/fundoplication. Anticonvulsants, gastroesophageal reflux disease, sleep, and behavioral medications were the most commonly prescribed drugs. STU was high among individuals with AS.

Conclusions

This study shows that individuals with AS have high HRU/STU, and apart from a few differences, HRU/STU was similar across molecular etiology. These results reflect usage in younger individuals and studies that describe HRU/STU in older individuals are needed.

Vagal nerve stimulation for medically refractory epilepsy in Angelman syndrome: a series of three cases

BACKGROUND

We describe three children with Angelman syndrome and medically refractory epilepsy.

METHODS

Case series of three pediatric patients with Angelman syndrome and medically refractory epilepsy. All three patients failed medical treatment and were recommended for vagal nerve stimulator (VNS) implantation.

RESULTS

Following VNS implantation, all three patients experienced reduction in seizure frequency greater than that afforded by medication alone.

CONCLUSION

We present vagal nerve stimulator implantation as a viable treatment option for medically refractory epilepsy associated with Angelman syndrome.

Unmet clinical needs and burden in Angelman syndrome: a review of the literature

Background

Angelman syndrome (AS) is a rare disorder with a relatively well-defined phenotype. Despite this, very little is known regarding the unmet clinical needs and burden of this condition, especially with regard to some of the most prevalent clinical features—movement disorders, communication impairments, behavior, and sleep.

Main text

A targeted literature review using electronic medical databases (e.g., PubMed) was conducted to identify recent studies focused on specific areas of the AS phenotype (motor, communication, behavior, sleep) as well as epidemiology, diagnostic processes, treatment, and burden. 142 articles were reviewed and summarized. Findings suggest significant impairment across the life span in all areas of function. While some issues may resolve as individuals get older (e.g., hyperactivity), others become worse (e.g., movement disorders, aggression, anxiety). There are no treatments focused on the underlying etiology, and the symptom-based therapies currently prescribed do not have much, if any, empirical support.

Conclusions

The lack of standardized treatment protocols or approved therapies, combined with the severity of the condition, results in high unmet clinical needs in the areas of motor functioning, communication, behavior, and sleep for individuals with AS and their families.

Main causes of hospitalization in people with Angelman syndrome

BACKGROUND

The objective was to describe the main causes of hospitalization in people with Angelman syndrome (AS).

METHOD

Population-based cross-sectional study in the Community of Madrid (CM), Spain. The information source for AS cases was the information system for rare diseases in the CM. Variables related to hospitalization, for the period 2006-2014, were the following: number of episodes, outcome, main cause, length of stay and type of admission. Main causes of hospitalization were described by age group and sex.

RESULTS

The most frequent causes of hospitalization were the following: oral-dental care (28.9%), seizures (19.6%), orthopaedic problems (14.4%) and acute respiratory disorders (12.4%). The percentage of hospitalizations was higher for oral-dental care in women and for orthopaedic problems in men (p-value <.05). Hospitalizations for an acute respiratory disorder were higher in adults (p-value <.05).

CONCLUSIONS

Some differences in the causes of hospitalization of people with AS were observed by sex and age.

A retrospective review to assess whether spinal fusion and scoliosis correction improved activity and participation for children with Angelman syndrome

OBJECTIVE

This study investigates outcome of scoliosis treatment for 11 children with Angelman syndrome (AS), with particular focus on activity, participation and the musculoskeletal factors that may affect these outcomes.

METHODS

Retrospective review of medical records, radiographs and questionnaires administered to caregivers of 11 children (8M:3F) with AS and scoliosis. Six underwent observational treatment during childhood and five underwent spinal fusion. The Activities Scale for Kids (ASKp) questionnaire was used to measure activity and participation. Questionnaire and radiographic data were recorded over a 2 year period.

RESULTS

In the observational group, scoliosis increased from 31° to 46°. Mean ASKp decreased from 13.8 to 11.9 (p = 0.06). In the operative group, scoliosis decreased from 68° to 29°. Mean ASKp increased from 11.4 to 15.9 (p < 0.01). There was also a reduction in spinal-related pain and mean number of hospital admissions for chest infection. However, there was a 60% major complication rate. There was no difference in mobility, GMFCS level, feeding or communication in either group before or after treatment.

CONCLUSION

In children with significant scoliosis and AS, spinal fusion was associated with a small improvement in activity and participation, reduction in pain and a decrease in frequency of severe chest infections. Non-operative treatment resulted in progression of scoliosis during childhood and decrease in activity.

"Over time it just becomes easier…": parents of people with Angelman syndrome and Prader-Willi syndrome speak about their carer role

PURPOSE

This study investigated two of the stresses experienced by parents caring for offspring with Angelman syndrome (AS) and Prader-Willi syndrome (PWS) in Western Australia, and identified their coping strategies.

METHODS

Parents of 19 offspring with AS and PWS participated in the Family Stress and Coping Interview which provides a stress level score, and a discussion of stressors and coping methods associated with 24 life situations, two of which are reported. All text was examined using directed content analysis.

RESULTS

Family carers (14/19) reported high stress associated with the initial diagnosis of AS or PWS in their offspring; and finding time for themselves. Stressors identified included lack of quality information about the disorder, time constraints and physical and emotional tiredness. Parents adopted a variety of coping strategies, including learning about the disorder, accepting the situation, seeking instrumental and social supports and dealing with problems.

CONCLUSIONS

No specific coping strategy was associated with reduced stress. However, parents felt that accurate and timely information during the diagnostic period helped. Parents used family and community support although there were difficulties accessing respite care. It is advised that government agencies, service providers, family members and peer support associations should provide practical and emotional support to assist the parents of offspring with AS and PWS, and indeed any form of intellectual disability, across the lifespan. Implications for Rehabilitation Long-term caring for offspring with AS or PWS can involve considerable stress for parents. Stress has been associated with poorer health outcomes for parental carers. Parents need a variety of practical and emotional supports to cope with stress, including timely access to information.

Angelman syndrome: A review highlighting musculoskeletal and anatomical aberrations

Angelman's syndrome (AS) is a genetic neurodevelopment disorder. The cause is a known abnormality involving the maternal inherited ubiquitin-protein ligase (UBE3A) gene. Clinical characteristics universal to the disorder are well documented in the literature and include developmental delay, seizures, ataxia, altered tone, severely impaired speech and intellect, as well as an overall happy demeanor, frequent bouts of laughter, and hypermotoric behavior. Associated with this disorder are several musculoskeletal aberrations. To date, a review of case studies reporting on these musculoskeletal changes has not been carried out. Thus, the purpose of this paper was to provide an overview of the musculoskeletal changes present in individuals with AS. In our review of 21 case reports from 1965-2013, the most consistently reported anatomical changes were of the craniofacial region. These include microcephaly, brachycephaly, a palpable occipital groove, prognathism, and wide spaced teeth. Other musculoskeletal abnormalities less frequently reported in the literature include scoliosis, excessive lumbar lordosis, and pes planus. Given that the majority of the case reports reviewed was of young children, the possibility of underreporting musculoskeletal changes which may manifest in the later years of life may be present. Early diagnosis and interventions to minimize secondary complications are crucial to maintain quality of life. An overall multidisciplinary approach is emphasized to maximize developmental potential for these individuals. Future prospective studies that follow patients into adulthood are needed to better understand the prevalence and development of secondary musculoskeletal changes, which in turn can inform intervention techniques and preventative measures. Clin. Anat. 29:561-567, 2016. © 2015 Wiley Periodicals, Inc.

Discovery of Rare Mutations in Autism: Elucidating Neurodevelopmental Mechanisms

Autism spectrum disorder (ASD) is a group of highly genetic neurodevelopmental disorders characterized by language, social, cognitive, and behavioral abnormalities. ASD is a complex disorder with a heterogeneous etiology. The genetic architecture of autism is such that a variety of different rare mutations have been discovered, including rare monogenic conditions that involve autistic symptoms. Also, de novo copy number variants and single nucleotide variants contribute to disease susceptibility. Finally, autosomal recessive loci are contributing to our understanding of inherited factors. We will review the progress that the field has made in the discovery of these rare genetic variants in autism. We argue that mutation discovery of this sort offers an important opportunity to identify neurodevelopmental mechanisms in disease. The hope is that these mechanisms will show some degree of convergence that may be amenable to treatment intervention.

Angelman syndrome in adulthood

Angelman syndrome (AS) is a neurogenetic disorder. The goal of this study was to investigate the primary health issues affecting adults with AS and to further characterize the natural history and genotype-phenotype correlations. Standardized phone interviews with caregivers for 110 adolescents and adults with AS were conducted. The impact of age, sex, and genotype on specific outcomes in neurology, orthopedics, internal medicine, and psychiatry were investigated. The mean age of individuals with AS was 24 years (range 16-50y). Active seizures were present in 41% of individuals, and 72% had sleep dysfunction. Significant constipation was present in 85%, and 32% were overweight or obese, with obesity disproportionately affecting women. Scoliosis affected 50% with a mean age at diagnosis of 12 years, and 24% of those diagnosed with scoliosis required surgery, an intervention disproportionately affecting men. Sixty-eight percent were able to walk independently, and 13% were able to speak 5 or more words. Self-injurious behavior was exhibited in 52% of individuals. The results of this study indicate that epilepsy severity may assume a bimodal age distribution: seizures are typically most severe in early childhood but may recur in adulthood. While late-adolescent and adult sleep patterns were improved when compared to the degree of sleep dysfunction present during infancy and childhood, the prevalence of poor sleep in adults remained quite high. Primary areas of clinical management identified include the following: seizures, sleep, aspiration risk, GERD, constipation, dental care, vision, obesity, scoliosis, bone density, mobility, communication, behavior, and anxiety.

Ethnicity and Geographic Distribution of Pediatric Chronic Ataxia in Manitoba

Background:

Genetic and environmental factors are important determinants of disease distribution. Several disorders associated with ataxia are known to occur more commonly in certain ethnic groups; for example, the disequilibrium syndrome in the Hutterites. The aim of this study was to determine the ethnic and geographic distribution of pediatric patients with chronic ataxia in Manitoba, Canada.

Methods:

We identified 184 patients less than 17 years-of-age with chronic ataxia during 1991-2008 from multiple sources. Their diagnosis, ethnicity and place of residence were determined following a chart review.

Results:

Most patients resided in Manitoba (N=177) and the majority in Winnipeg, the provincial capital. Thirty five Aboriginal, 29 Mennonite and 11 Hutterite patients resided in Manitoba. The latter two groups were significantly overrepresented in our cohort. Ataxia telangiectasia, mitochondrial disorders, and non-progressive ataxia of unknown etiology associated with pyramidal tracts signs and developmental delay were significantly more common in Mennonite patients. Four of five patients with neuronal migration disorders associated with chronic ataxia were Aboriginal. Few isolated disorders with chronic ataxia occurred in the 11 Hutterite patients including a Joubert syndrome related disorder.

Conclusions:

Three disorders associated with chronic ataxia were more prevalent than expected in Mennonites in Manitoba. Few rare disorders were more prevalent in the Hutterite and Aboriginal population. Further research is needed to determine the risk factors underlying these variations in prevalence within different ethnic groups. The unique risk factor profiles of each ethnic group need to be considered in health promotion endeavors.

Angelman syndrome in Denmark. birth incidence, genetic findings, and age at diagnosis

Angelman syndrome (AS) is a neurogenetic disorder caused by loss of expression of the maternal imprinted gene UBE3A on chromosome 15q11.2-q13. Clinical features of AS include severe intellectual disability, a happy disposition, ataxia, mandibular prognatism, and epilepsy. Our objectives were to examine the birth incidence of AS in Denmark and to characterize the size of the 15q11.2-q13 deletions with 1,000K array CGH. In addition, we analyzed genotype differences in regard to age at diagnosis and investigated the occurrence of deletions/duplications outside the 15q11.2-q13 regions. We identified 51 patients with genetically verified AS, which corresponded to a birth incidence of 1:24,580 (95%CI: 1:23,727-1:25,433). Thirty-six patients showed a deletion; 13 had a Class I deletion and 20 had a Class II deletion. There was bimodal distribution of the BP3 breakpoint. Three patients had larger and atypical deletions, with distal breakpoints telomeric to BP3. Five patients had paternal uniparental disomy (pUPD) of chromosome 15, and four had a verified UBE3A mutation. Additional deletions/duplications outside the 15q11.2-q13 areas were demonstrated in half the participants. Six harbored more than one CNV. Mean age at diagnosis was 21 months (95%CI: 17-23 months) for children with a deletion and 46 months (95%CI: 36-55 months) for children with pUPD or a UBE3A mutation (P < 0.01). The presence of a CNV outside 15q11.2-q13 did not have an impact on age at diagnosis.

Autism spectrum disorders: the quest for genetic syndromes

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disabilities with various etiologies, but with a heritability estimate of more than 90%. Although the strong correlation between autism and genetic factors has been long established, the exact genetic background of ASD remains unclear. A number of genetic syndromes manifest ASD at higher than expected frequencies compared to the general population. These syndromes account for more than 10% of all ASD cases and include tuberous sclerosis, fragile X, Down, neurofibromatosis, Angelman, Prader-Willi, Williams, Duchenne, etc. Clinicians are increasingly required to recognize genetic disorders in individuals with ASD, in terms of providing proper care and prognosis to the patient, as well as genetic counseling to the family. Vice versa, it is equally essential to identify ASD in patients with genetic syndromes, in order to ensure correct management and appropriate educational placement. During investigation of genetic syndromes, a number of issues emerge: impact of intellectual disability in ASD diagnoses, identification of autistic subphenotypes and differences from idiopathic autism, validity of assessment tools designed for idiopathic autism, possible mechanisms for the association with ASD, etc. Findings from the study of genetic syndromes are incorporated into the ongoing research on autism etiology and pathogenesis; different syndromes converge upon common biological backgrounds (such as disrupted molecular pathways and brain circuitries), which probably account for their comorbidity with autism. This review paper critically examines the prevalence and characteristics of the main genetic syndromes, as well as the possible mechanisms for their association with ASD.

The epidemiology of intermittent and chronic ataxia in children in Manitoba, Canada

AIM

To determine the epidemiology of chronic ataxia in children in Manitoba, Canada.

METHOD

A retrospective study using multiple sources and disease codes identified children (age 0-16y) with chronic ataxia (>2mo duration or recurrent episodes of ataxia) seen at Winnipeg Children's Hospital from 1991 to 2008. Patients with isolated peripheral nerve diseases, vestibular disorders, or brain tumors were excluded.

RESULTS

We identified 184 patients (males=females; mean age 15y, SD 7y 8mo) with chronic ataxia. Median age at the presenting symptom onset was 1 year 3 months and at ataxia onset 3 years 1 month. Median duration of follow-up was 6 years 5 months. During the study period, the crude incidence rate was 5.77 in 10,000; the crude prevalence rate was 6.59 in 10,000; and the crude mortality rate 0.446 in 10,000. The most common presenting symptoms were developmental delay, ataxia, or seizures. The most common diagnoses (known in 129) were Angelman syndrome (n=16), ataxia telangiectasia (n=13), mitochondrial disease (n=9), Friedreich ataxia (n=7), stroke (n=7), and familial/genetic episodic ataxia (n=7).

INTERPRETATION

Chronic ataxia is a relatively common early-presenting symptom in childhood. A specific diagnosis is possible in 70% of patients after extensive investigations. The mortality rate is relatively low and the disease burden is high with significant comorbidities including developmental delay and epilepsy.

Proposta de atuação fisioterapêutica em uma criança com síndrome de Angelman, enfatizando o equilíbrio postural: estudo de caso

A síndrome de Angelman (SA) é caracterizada por alterações neuromotoras como marcha atáxica e atraso na aquisição de habilidades motoras, porém são escassos os estudos investigando o efeito de intervenções aplicadas a essa população. O objetivo do estudo foi verificar o efeito de um treino de equilíbrio em uma criança com SA. Participou do estudo uma criança de nove anos de idade com diagnóstico de SA, sexo feminino. Foi aplicado um protocolo para treino de equilíbrio por oito semanas, com frequência de duas vezes por semana. O treino consistiu em atividades envolvendo equilíbrio estático sob diversas condições de dificuldade. Após o treino, a análise de biofotogrametria computadorizada do equilíbrio estático revelou redução do grau de oscilação, que passou de 38° para 13,78°. A pontuação na escala de Berg passou de 27 pontos, na avaliação, para 37 pontos na reavaliação. No teste Timed Up & Go, a criança realizou a tarefa em 15 segundos, na avaliação, e, na reavaliação, em 12 segundos. Em conjunto, os resultados sugerem que o treino favoreceu melhora no equilíbrio estático e dinâmico, bem como na mobilidade funcional.

[Anesthesia and Angelman syndrome]

Angelman syndrome (AS) is a rare neurodevelopmental disorder with an incidence of 1:10,000-1:40,000 caused by deficient genetic imprinting in the chromosomal segment 15q11-q13. Experimental data suggest that the gamma-aminobutyric acid A (GABA(A)) receptor as well as the N-methyl-D-aspartate (NMDA) or α-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA) receptors may be affected by this condition. The first description of the syndrome goes back to 1965 when the British pediatrician Harry Angelman (1915-1996) recognized similar clinical features in three children. Angelman's description of puppet children was changed to happy puppet syndrome 2 years later before this euphemistic denotation was replaced by the concept Angelman syndrome over the years. Angelman syndrome is characterized by ataxia, jerky movements especially hand flapping, a seizure disorder with a characteristic electroencephalogram (EEG), severe learning difficulties, a happy disposition, lack of verbal communication and dysmorphic facial features. Most hospitalizations are caused by epilepsy and the most common indications for surgical procedures are in dental medicine. The first anesthesiology case report to be published dates back to 2001. A total of 13 cases have now been published and in 11 cases the age was registered (mean age 11.6 years, standard deviation 11.7 and 2 outliers aged 27 and 40 years). In this paper, the published case reports are contrasted with 15 cases of anesthesia in 6 patients with AS who underwent surgery during 14 years of routine operations at a Berlin anesthesiology clinic (mean age 15.9 years, standard deviation 4.2 with no outliers). Besides neurosurgical and orthopedic operations most were dental interventions. Summarized, these cases of anesthesia and the results of the published case reports allow the formulation of guidelines for administration of anesthesia in AS cases but do not permit conclusions on which method of anesthesia is the safest for AS patients. For the preoperative consultation and anesthetization, communication with the patients requires the aid of parents or other relatives. Water and reflecting surfaces may be used to gain contact with AS patients. Patients with AS feel pain like any other person although they are frequently smiling and laughing and this has to be considered especially in major surgery (e.g. scoliosis surgery). The most important life-threatening complication is bradycardia due to vagal hypertonia which can lead to asystole with delayed response to atropine. None of the Berlin patients had severe bradycardia but the complication has to be taken into consideration. The use of drugs to ensure complete reversal of neuromuscular relaxation should be avoided because anticholinergic agents could cause bradycardia. The use of sugammadex in cases of AS has not been tested. To avoid elevation of the vagal tone, the indications for laparascopy have to be considered very carefully. There is no evidence that any drug or hypnotic may be more appropriate or advantageous. Balanced anesthesia and total intravenous anesthesia are possible but the duration of drug effect has to be taken into account. If ketamine is used the side-effects of the drug (psychomimetic reactions, muscular rigidity) should be prevented by the consistent administration of propofol, midazolam or thiopental. Usually AS patients are agitated so that regional anesthesia techniques are difficult to administer. If regional anesthesia does have considerable advantages over general anesthesia in a particular case, peripheral regional anesthesia should be preferred, especially because scoliosis is often present. There is no evidence that AS patients cause more intubation problems but because of facial dysmorphia accurate evaluation is needed in advance. This is even more important for older AS patients because the dysmorphia tends to accelerate during the course of life. Although epilepsy is the primary feature of AS, not every EEG alteration indicates the presence of epilepsy. The advantage in using neuromonitoring for measuring the depth of anesthesia is limited. Administration of anticonvulsants must be continued if they were used preoperatively.

Maternal parenting stress in families with a child with Angelman syndrome or Prader-Willi syndrome

BACKGROUND

Parenting stress was investigated in mothers with a child with Angelman syndrome (AS) or Prader-Willi syndrome (PWS), which are genetically related.

METHOD

Mothers of 24 children with AS and 23 children with PWS (2-12 years) completed the Nijmegen Parenting Stress Index-Short, Developmental Behaviour Checklist, and Vineland Screener 0-12.

RESULTS

Parenting stress was high for 58% of AS and 26% of PWS cases. For both syndromes, no relationship existed with the child's gender, age, or behavioural problems. In PWS there was no effect on level of functioning. Overall, more mothers with a child with AS perceived high parenting stress. When children showed low levels of behavioural problems this difference was contained. However, when children exhibited severe behavioural problems, parenting stress was the same for both syndromes.

CONCLUSION

In AS professional family support is essential, since parenting is stressful for many mothers. In PWS, this is especially the case when behavioural problems are present.

Genome-wide gene expression profiling of the Angelman syndrome mice with Ube3a mutation

Angelman syndrome (AS) is a human neurological disorder caused by lack of maternal UBE3A expression in the brain. UBE3A is known to function as both an ubiquitin-protein ligase (E3) and a coactivator for steroid receptors. Many ubiquitin targets, as well as interacting partners, of UBE3A have been identified. However, the pathogenesis of AS, and how deficiency of maternal UBE3A can upset cellular homeostasis, remains vague. In this study, we performed a genome-wide microarray analysis on the maternal Ube3a-deficient (Ube3a(m-/p+)) AS mouse to search for genes affected in the absence of Ube3a. We observed 64 differentially expressed transcripts (7 upregulated and 57 downregulated) showing more than 1.5-fold differences in expression (P<0.05). Pathway analysis shows that these genes are implicated in three major networks associated with cell signaling, nervous system development and cell death. Using quantitative reverse-transcription PCR, we validated the differential expression of genes (Fgf7, Glra1, Mc1r, Nr4a2, Slc5a7 and Epha6) that show functional relevance to AS phenotype. We also show that the protein level of melanocortin 1 receptor (Mc1r) and nuclear receptor subfamily 4, group A, member 2 (Nr4a2) in the AS mice cerebellum is decreased relative to that of the wild-type mice. Consistent with this finding, expression of small-interfering RNA that targets Ube3a in P19 cells caused downregulation of Mc1r and Nr4a2, whereas overexpression of Ube3a results in the upregulation of Mc1r and Nr4a2. These observation help in providing insights into the genesis of neurodevelopmental phenotype of AS and highlight specific area for future research.

Angelman syndrome: current understanding and research prospects

Angelman syndrome is a neurogenetic disorder characterized by developmental delay, severe intellectual disability, absent speech, exuberant behavior with happy demeanor, motor impairment, and epilepsy, due to deficient UBE3A gene expression that may be caused by various abnormalities of chromosome 15. Recent findings in animal models demonstrated altered dendritic spine formation as well as both synaptic [including gamma-aminobutyric acid (GABA)(A) and N-methyl-D-aspartate (NMDA) transmission] and nonsynaptic (including gap junction) influences in various brain regions, including hippocampus and cerebellar cortex. Reversal of selected abnormalities in rescue genetically engineered animal models is encouraging, although it should not be misinterpreted as promising "cure" for affected patients. Much research is still required to fully understand the functional links between lack of UBE3A expression and clinical manifestations of Angelman syndrome. Studies of regulation of UBE3A expression, including imprinting-related methylation, may point to possibilities of therapeutic upregulation. Understanding relevant roles of the gene product might lead to targeted intervention. Further documentation of brain network dynamics, with particular emphasis on hippocampus, thalamocortical, and cerebellar networks is needed, including in a developmental perspective. There is also a need for further clinical research for improving management of problems such as epilepsy, behavior, communication, learning, motor impairment, and sleep disturbances.

SLC9A6 mutations cause X-linked mental retardation, microcephaly, epilepsy, and ataxia, a phenotype mimicking Angelman syndrome

Linkage analysis and DNA sequencing in a family exhibiting an X-linked mental retardation (XLMR) syndrome, characterized by microcephaly, epilepsy, ataxia, and absent speech and resembling Angelman syndrome, identified a deletion in the SLC9A6 gene encoding the Na(+)/H(+) exchanger NHE6. Subsequently, other mutations were found in a male with mental retardation (MR) who had been investigated for Angelman syndrome and in two XLMR families with epilepsy and ataxia, including the family designated as having Christianson syndrome. Therefore, mutations in SLC9A6 cause X-linked mental retardation. Additionally, males with findings suggestive of unexplained Angelman syndrome should be considered as potential candidates for SLC9A6 mutations.

Epilepsy in Angelman syndrome

Angelman syndrome is a neurogenetic disorder caused by lack of UBE3A gene expression from the maternally inherited chromosome 15 due to various 15q11-q13 abnormalities. In addition to severe developmental delay, virtual absence of speech, motor impairment, a behavioural phenotype that includes happy demeanor, and distinctive rhythmic electroencephalographic features, over 90% of patients have epilepsy. Many different seizure types may occur, atypical absences and myoclonic seizures being particularly prevalent. Non-convulsive status epilepticus is common, sometimes in the context of the epileptic syndrome referred to as myoclonic status in non-progressive encephalopathies. Epilepsy predominates in childhood, but may persist or reappear in adulthood. Management is difficult in a proportion of patients. It might be improved by better understanding of pathophysiology. Current hypotheses involve abnormal inhibitory transmission due to impaired regulation of GABAA receptors related to functional absence of UBE3A and abnormal hippocampal CaMKII activity.

The overlapping spectrum of rett and angelman syndromes: a clinical review

Rett and Angelman syndromes comprise part of the spectrum of neurologic disorders associated with autism. Their clinical presentations overlap, with both presenting in later infancy with global developmental delays, severe speech and communication impairments, progressive microcephaly, seizures, autistic behaviors, and characteristic albeit different movement disorders and stereotypic hand movements. Although other features can help differentiate these disorders, significant phenotypic overlap and variation in severity sometimes cloud the underlying diagnosis. Rett syndrome is caused by a mutation in the MECP2 gene located on Xq28, whereas Angelman syndrome results from the loss of UBE3A function on chromosomal region 15q11-q13 related to a variety of molecular genetic mechanisms. Recent advances have uncovered interactions between these and other genes that affect the function and structure of neurons in the brain. The reversal of symptoms of Rett syndrome in a mature mouse model suggests the possibility for treatment of these and perhaps other autism-related disorders in the future.

Prevalence of Angelman syndrome and Prader–Willi syndrome in Estonian children: Sister syndromes not equally represented

In 2000-2004, we performed a focused search for individuals with Angelman syndrome (AS) and Prader-Willi syndrome (PWS) aiming to establish the prevalence data for the individuals born between 1984 and 2004 in Estonia. All persons with probable AS or PWS (n = 184) were studied using the DNA methylation test. Individuals with abnormal methylation were all further tested by chromosomal and FISH analysis, and if necessary for uniparental disomy and UBE3A gene mutation. Nineteen cases with abnormal methylation test result were identified. Seven of them had AS, including six (85.7%) due to 15q11-13 deletion and one paternal UPD15. Twelve subjects had PWS: 4 (33%) 15q11-13 deletions, 6 (50%) maternal UPD15, 1 unbalanced chromosome 14;15 translocation resulting in a chromosome 15pter-q13 deletion, and 1 Robertsonian 15q;15q translocation. The minimum livebirth prevalence in 1984-2004 for AS was 1:52,181 (95% CI 1:25,326-1:1,29,785) and for PWS 1:30,439 (95% CI 1:17,425-1:58,908). The livebirth prevalence of AS and PWS increased within this period, but the change was statistically significant only for PWS (P = 0.032), from expected 1:88,495 (95% CI 1:24,390-1:3,22,580) to expected 1:12,547 (95% CI 1:540-1:29,154). Six individuals with AS and 11 with PWS were alive on the prevalence day (January 1, 2005), indicating the point prevalence proportion of 1:56,112 (95% CI 1:25,780-1:1,52,899) and 1:30,606 (95% CI 1:17,105-1:61,311), respectively. Our results showing the birth prevalence of AS 1.7 times less than PWS challenge the opinion that both syndromes are equally represented, and are in line with the view that mutations in sperm and oocytes occur at different frequencies.