Epilepsy in Angelman syndrome: A questionnaire-based assessment of the natural history and current treatment options

Purpose:   Angelman syndrome (AS) commonly presents with epilepsy (>80%). The goal of this study was to examine the natural history and various treatments of epilepsy in AS in a large population.
Methods:   A detailed electronic survey containing comprehensive questions regarding epilepsy in AS was conducted through the Angelman Syndrome Foundation.
Results:   There were responses from 461 family members of individuals with AS, of whom 86% had epilepsy (60% with multiple seizure types), the most common being atonic, generalized tonic–clonic, absence, and complex partial. Partial-onset seizures only were reported in 11% of those with epilepsy. Epilepsy was most common among those with maternal deletions and unknown subtypes, with catastrophic epilepsies present in only these two subtypes. These epilepsies were refractory to medication, with only 15% responding to the first antiepileptic drug (AED). The most commonly prescribed AED were valproic acid and clonazepam, but lamotrigine and levetiracetam appeared to have similar efficacy and tolerability.
Discussion:   This is the largest study to date assessing epilepsy in AS. Although epilepsy in AS is considered a generalized epilepsy, there was a high prevalence of partial seizures. There are few previous data regarding the use of newer AED in AS, and the results of this study suggest that these newer agents, specifically levetiracetam and lamotrigine, may have efficacy similar to that of valproic acid and clonazepam, and that they appear to have similar or better side-effect profiles. Nonpharmacologic therapies such as dietary therapy and vagus nerve stimulation (VNS) also suggest favorable efficacy and tolerability, although further studies are needed.     

Evolution of Epilepsy and EEG Findings in Angelman Syndrome

Summary: Purpose: To evaluate the evolution of epileptic seizures and EEG features in a large group of patients with Angelman syndrome (AS). Methods: Thirty-six patients with AS with a proven chromosome 15qll–13 deletion were retrospectively analyzed with regard to their epilepsy and EEG findings by examination of patient files and EEGs. All EEGs were reviewed by one of the authors. A logistic regression model, with a follow-up from 1 to 39 years (mean, 15 years), was used for statistical analysis. Results: Epileptic seizures had occurred in 30 (83%) patients. In 43% of them, the initial symptoms of epilepsy were febrile convulsions in infancy. In childhood, epilepsy could start with almost any type of seizure. Atypical absences and myoclonic seizures prevailed in adulthood. Epileptic seizures were present in 92% of the adult patients. The most typical EEG findings were rhythmic triphasic delta waves of high amplitude with a maximum over the frontal regions, identified in 99 (66%) of 150 EEGs, and continuously or intermittently, in 30 (83%) of 36 patients with AS. In 47% it was present even before a clinical diagnosis of AS was considered. High-amplitude rhythmic 4–6/s slow activity, seen in 44 (29%) of 150 EEGs, was not present after the age of 12 years. Conclusions: In contrast to previous reports suggesting a decreasing frequency of epileptic seizures with age, we found that 92% of the adult patients with AS continued to have epileptic seizures. The most typical EEG finding in AS, in both children and adults, was the presence of frontal triphasic delta waves. In mentally retarded patients, this EEG pattern should point the physician in the direction of AS.     

Epilepsy and cataplexy in Angelman syndrome. Genotype-phenotype correlations

BackgroundAngelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability, epilepsy, and low threshold for laughter.AimsWe investigated the occurrence and severity of epilepsy and laughter-induced loss of postural muscle tone determined by the different genetic subtypes.MethodsThis study included 39 children with AS. Deletion breakpoints were determined by high resolution CGH microarray (1 × 1 M Agilent). Clinical data were based on a parent interview and medical record review.ResultsAll patients with AS based on a deletion had epilepsy. Epilepsy was present in 3/4 children with UBE3A mutation, and 4/5 with pUPD. Onset of epilepsy occurred earlier in deletion cases compared to pUPD or UBE3A mutations cases. Laughter-induced postural muscle tone loss occurred only among deletion cases. We found no differences in severity of epilepsy between children with a larger Class I or a smaller Class II deletions, or between the total group with a deletion compared to children with pUPD or a UBE3A mutation. The drugs most frequently prescribed were benzodiazepines in monotherapy, or a combination of benzodiazepines and valproic acid.ConclusionEpilepsy is very common in patients with AS, especially in patients with a deletion. Postural muscle tone loss and collapsing during outbursts of laughter were seen in patients with a deletion only.     

Epilepsy and the sleep–wake patterns found in Angelman syndrome

Sleep disturbances and epilepsy are common in Angelman syndrome (AS). This study examines seizure variables and sleep in a large AS cohort. Sleep disturbances and epilepsy were assessed in 290 individuals with AS using two questionnaires, including the Behavioral Evaluation of Disorders of Sleep (BEDS). Sensitivity to the sleeping environment, decreased nightly hours of sleep, and a difficulty initiating sleep were significantly correlated with the presence of epilepsy, particularly focal seizures. Use of multiple anticonvulsant drugs was shown to affect sleep. No significant associations were present between molecular subtypes of AS and individual sleep factors. Sleep problems appeared to be associated with epilepsy in individuals with AS, especially with focal and absence seizures and multiple seizure types. Results were consistent with those of prior studies assessing sleep in AS. Severity of epilepsy and use of anticonvulsant drugs may be related to a higher degree of sleep disturbance in this population.     

Epilepsy in Angelman Syndrome Associated with Chromosome 15q Deletion

We report eight sporadic cases of typical Angelman syndrome (AS) associated with chromosome 15q12 deletion. Age at first visit was 3-35 months (average 18 months), and follow-up period was 4-20 years (average 14.1 years). The characteristic features of epilepsy in AS are (a) seizure onset in early childhood (8 of 8); (b) evolution of seizure type with age (8 of 8); (c) EEG abnormality changes from high-voltage slow bursts (HVS) in infancy to diffuse spike and waves in middle childhood (4 of 5); (d) atypical absence seizures (8 of 8), often occurring as atypical absence status (4 of 8); and (e) diminution of seizure discharges and clinical seizures after puberty (7 of 7). We believe that AS may frequently exist in the intractable epilepsies of childhood with severe mental retardation. We stress the importance of AS as one of the main etiologic background diseases of the intractable epilepsies with infantile onset such as West syndrome, Lennox-Gastaut syndrome, and others.     

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 γ-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.     

Implications of slow waves and shifting epileptiform discharges in Angelman syndrome

Objective: Angelman syndrome is a genetic syndrome resulted from a lack of UBE3A gene expression of the maternally inherited abnormalities of chromosome 15q11-q13. About 90% of patients with Angelman syndrome experience epilepsy and its distinctive electroencephalographic changes. Epilepsy predominates in childhood, but may persist in adulthood. The seizure types may be quite varied and sometimes difficult to control. Methods: We retrospectively reviewed and analyzed data of 18 patients with genetically and clinically confirmed Angelman syndrome at Asan Medical Center. Results: An analysis of 53 electroencephalography (EEG) records from 18 patients showed that diffuse slow-wave background patterns were significantly associated with uncontrolled periods of epilepsy. Moreover, epileptiform discharges tended to shift from posterior to anterior head regions over time after an initial normal pattern at a young age. Conclusions: Children with Angelman syndrome follow general developmental patterns, with specific patterns of EEG reflecting the maturational pattern of the brain and epileptic activity.     

Toilet training in individuals with Angelman syndrome: A case series

Objective: To assess if adapted versions of the response restriction toilet training protocol, based on the behavioral phenotype of Angelman syndrome (AS), were successful in fostering urinary continence in seven individuals with AS.

Method: Data were collected in AB-designs during baseline, training, generalization and follow-up. The response restriction protocol was adapted: individuals were trained in their natural environment, were prompted to void and along with improving continence, the interval between voids was prolonged and time-on-toilet decreased.

Results: During generalization five individuals had less than two accidents and one to six correct voids per day; during baseline more accidents and/or less correct voids occurred. In two participants correct voids increased, but several accidents still occurred. Three participants maintained positive results after 3–18 months.

Conclusion: Despite their intellectual and behavioral challenges, urinary continence can be acquired in AS. Several indications of voiding dysfunctions were found; further research is indicated.     

Sibling relationships in individuals with Angelman syndrome: A comparative study

Objective: Investigating the impact of Angelman syndrome on the sibling relationship.

Methods: This study explored differences in sibling relationships between children with a typically-developing sibling (n?=?55) and children with a sibling with Angelman syndrome (n?=?44). Sibling relationships were compared on four factors and 16 sub-scales of the Sibling Relationship Questionnaire-Revised.

Results: Results showed significant differences in mean scores on each of the four factors (i.e. Warmth/Closeness, Conflict, Rivalry and Dominance/Nurturance) and most of the sub-scales. ANCOVAs showed that demographic variables (number of siblings, living in a two-parent vs single parent household, gender, participant's age, place of residence) did not influence significant differences in sibling relationships between the two groups.

Conclusion: Having a brother or sister with Angelman syndrome may influence the way in which the sibling perceives the sibling relationship. This may have important implications for family-centred intervention for this population.     

Low glycemic index treatment for seizures in Angelman syndrome

Purpose: The low glycemic index treatment (LGIT) is a high fat, limited carbohydrate diet used in the treatment of epilepsy. The purpose of this study was to assess the efficacy and tolerability of the LGIT for the treatment of refractory seizures in pediatric patients with Angelman syndrome. Methods: A pediatric Angelman syndrome cohort with refractory epilepsy was treated with the LGIT and followed prospectively over 4 months. Parents recorded a daily seizure log for a minimum of 1 month prior to the start of treatment as well as throughout the LGIT trial. Electroencephalography (EEG) and neuropsychological assessments (Scales of Independent Behavior‐Revised and the Vineland Adaptive Behavior Scales‐2nd Edition were obtained for each subject at both baseline and 4‐month follow‐up time points. Clinical evaluations of subjects were completed by a neurologist and dietitian at the time of enrollment, as well as following both the first and fourth months of dietary therapy. At each time point, blood for laboratory chemistries was drawn and anthropometric measures were obtained. Key Findings: Six children (mean age 3.3 years, range 1.1–4.8) with genetically confirmed Angelman syndrome initiated the LGIT, and completed the trial with no significant adverse events. Cohort averages for indices of seizure severity were as follows: age of 1.6 years at seizure onset, 3 lifetime antiepileptic drugs tried (range 1–6), and baseline seizure frequency of 10.1 events/week (range: 0.4–30.9). All subjects had a decrease in seizure frequency on the LGIT, with five of six exhibiting >80% seizure frequency reduction. All posttrial EEG studies showed improvement and three of four children with epileptiform activity on his or her baseline EEG had no discharges present on follow‐up EEG. Developmental gains were noted by parents in all cases, although few of these neurocognitive gains were statistically significant on neuropsychological assessment. Significance: This is the first prospective study assessing the LGIT for epilepsy. Our results indicate that this dietary therapy is highly effective in treating Angelman syndrome–related seizures. The diet was well tolerated by subjects as evidenced by five of six subjects remaining on the LGIT after completion of the trial. Beyond the prospective trial window, all five subjects who remained on the diet had >90% seizure reduction after 1 year of LGIT therapy. Despite the small sample size in this prospective study, the results indicate a potentially higher degree of efficacy of the LGIT for the Angelman syndrome population than that observed in the general epilepsy population. Although this study is too small to make definitive recommendations, these results suggest that the LGIT is a promising treatment option for Angelman syndrome–related epilepsy.     

Incontinence in individuals with Angelman syndrome: A comparative study

Frequency and type of incontinence and variables associated with incontinence were assessed in individuals with Angelman syndrome (AS; n = 71) and in a matched control group (n = 69) consisting of individuals with non-specific intellectual disability (ID). A Dutch version of the “Parental Questionnaire: Enuresis/Urinary Incontinence” (Beetz, von Gontard, & Lettgen, 1994) was administered and information on primary caretakers’ perspectives regarding each individual's incontinence was gathered. Results show that diurnal incontinence and fecal incontinence during the day more frequently occurred in the control group than in the AS group. In both groups, nocturnal enuresis was the most common form of incontinence. More incontinence was seen in individuals with AS who were younger, had a lower level of adaptive functioning and/or had epilepsy. Individuals with AS were able to stay dry for longer periods of time than the controls and often showed both in-toilet urination and urinary accidents during the day, whereas accidents and correct voids during the day were more set apart in the control group. Also, persons with AS had a lower micturition frequency implying possible voiding postponement. Both groups showed high rates of LUTS (lower urinary tract symptoms) possibly indicative of functional bladder disorders such as voiding postponement, dysfunctional voiding, or even an underactive bladder. In general, most primary caretakers reported severe intellectual disability as the main cause for urinary incontinence. Based on these results incontinence does not appear to be part of the behavioral phenotype of Angelman syndrome. Therefore, pediatric or urologic diagnostics and treatment are recommended for all persons with incontinence and intellectual disability. Further implications for practice and research are given.     

Adverse Effects of Vigabatrin in Angelman Syndrome

Summary: New antiepileptic drugs designed for enhancing GABAergic inhibition, such as vigabatrin (VGB) may be effective in Angelman syndrome (AS), because associated convulsions could be related to a reduced GABA-receptor density or receptor abnormality. From our preliminary experiences in four children with AS treated with VGB, we conclude that it may induce and increase seizures in patients with AS.     

Perampanel for nonepileptic myoclonus in Angelman syndrome

BackgroundAngelman syndrome (AS) is a neurodegenerative disorder caused by functional loss of the maternal ubiquitin-protein ligase 3A gene. Nonepileptic myoclonus, also described as tremulous movement, often occurs during puberty and increases in adulthood. The involuntary movement in AS has not been defined patho-physiologically and the drugs used such as levetiracetam and piracetam are not always effective. Recently, the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor antagonist, perampanel (PER), was used to alleviate myoclonus in progressive myoclonus epilepsy. Herein, we tested the efficacy of PER for nonepileptic myoclonus.Methods and resultsFour patients with AS, aged from 20 to 40 years at the beginning of treatment, were enrolled in our study. All patients reported disruption to their daily lives from the myoclonus movement. They experienced mild to moderate improvement with the starting dose of 2 mg. The dose was increased to 4 mg in one patient to achieve sufficient efficacy, while two had their dose reduced to 1 mg due to dizziness or possible exacerbation of myoclonus. The last patient continued to take the starting dose. Follow-up over 16–20 months revealed a significant reduction in the severity of nonepileptic myoclonus in all patients.ConclusionOur study suggests that PER could be one of the promising drugs for nonepileptic myoclonus in AS.     

Identification of Genetic Defect of an Epilepsy: Strategies for Therapeutic Advances

Summary: Advances in molecular genetics and molecular biology are transforming the biology of human disease. Cures for diseases previously refractory to all treatments have become the reality for some disorders and the legitimate promise for others. In the case of the epilepsies, identification of mutant genes underlying familial epilepsies may lead to a new pharmacology, through the development of in vitro expression systems permitting rapid search for novel drugs, creation of highly specific animal models based on expression of the precise mutation, and correction of disease phenotype by introducing novel and highly specific genetic information into the person with epilepsy.     

Neurovisual profile in children affected by Angelman syndrome

BackgroundAngelman syndrome (AS) is a rare neurogenetic disorder caused by altered expression of the maternal copy of the UBE3A gene. Together with motor, cognitive, and speech impairment, ophthalmological findings including strabismus, and ocular fundus hypopigmentation characterize the clinical phenotype. The aim of this study was to detail the neurovisual profile of children affected by AS and to explore any possible genotype-phenotype correlations.MethodsThirty-seven children (23 females, mean age 102.8 ± 54.4 months, age range 22 to 251 months) with molecular confirmed diagnosis of AS were enrolled in the study. All underwent a comprehensive video-recorded neurovisual evaluation including the assessment of ophthalmological aspects, oculomotor functions, and basic visual abilities.ResultsAll children had visual impairments mainly characterized by refractive errors, ocular fundus changes, strabismus, discontinuous/jerky smooth pursuit and altered saccadic movements, and/or reduced visual acuity. Comparing the neurovisual profiles between the deletion and non-deletion genetic subgroups, we found a significant statistical correlation between genotype and ocular fundus hypopigmentation (p = 0.03), discontinuous smooth pursuit (p < 0.05), and contrast sensitivity abnormalities (p < 0.01) being more frequent in the deletion subgroup.ConclusionsSubjects affected by AS present a wide spectrum of neurovisual impairments that lead to a clinical profile consistent with cerebral visual impairment (CVI). Moreover, subjects with a chromosome deletion show a more severe visual phenotype with respect to ocular fundus changes, smooth pursuit movements, and contrast sensitivity. Early detection of these impaired visual functions may help promote the introduction of neurovisual habilitative programs which can improve children’s visual, neuromotor, and cognitive outcomes.     

Utility of the Scalp-Recorded Ictal EEG in Childhood Epilepsy

PURPOSE: To evaluate the usefulness of the scalp-recorded ictal EEGs in diagnosing childhood epilepsy. METHODS: We analyzed the ictal EEGs of 259 seizures in 183 patients who visited the department of child neurology, Okayama University Medical School, during the past 6 years. RESULTS: We divided all seizures into the following four categories, according to the diagnostic usefulness of ictal EEGs in determining the seizure type: 1. (a) Ictal EEGs confirmed the diagnosis of the seizure type based on seizure symptoms (101 seizures); (b) Ictal EEGs aided in the classification of the seizure type based on the seizure symptoms (101 seizures); (c) Ictal EEGs corrected errors in the classification (37 seizures); and (d) Ictal EEGs revealed previously unreported/undocumented seizure type (20 seizures). 2. Of the 37 misdiagnosed seizures (group C), 11 were nonepileptic seizures misdiagnosed as epileptic seizures, eight were complex partial seizures (CPS) misdiagnosed as the other seizure types, and 10 were other seizure types misdiagnosed as CPSs. 3. Of the 20 previously unreported/undocumented seizures (group D), nine were myoclonic seizures, five were absence seizures, five were CPS, and one was tonic spasms. 4. Seventy-two patients had CPS. Among them, 11 patients showed no epileptic spikes in their interictal EEG recordings. Therefore, ictal recordings confirmed the diagnosis of epilepsy. CONCLUSIONS: Ictal EEG recording is a very useful diagnostic tool not only for determining seizure types, but also for uncovering the existence of the unsuspected seizure types. It supplies the physician with useful information for the classification and the treatment of epilepsy. In particular, ictal EEGs are useful in diagnosing patients with CPS.