Long-term neurological outcome in children with early-onset epilepsy associated with tuberous sclerosis

Common epilepsy variants from the general population are not associated with epilepsy among individuals with tuberous sclerosis complex

Common genetic variants identified in the general population have been found to increase phenotypic risks among individuals with certain genetic conditions. Up to 90% of individuals with tuberous sclerosis complex (TSC) are affected by some type of epilepsy, yet the common variants contributing to epilepsy risk in the general population have not been evaluated in the context of TSC-associated epilepsy. Such knowledge is important to help uncover the underlying pathogenesis of epilepsy in TSC which is not fully understood, and critical as uncontrolled epilepsy is a major problem in this population. To evaluate common genetic modifiers of epilepsy, our study pooled phenotypic and genotypic data from 369 individuals with TSC to evaluate known and novel epilepsy common variants. We did not find evidence of enhanced genetic penetrance for known epilepsy variants identified across the largest genome-wide association studies of epilepsy in the general population, but identified support for novel common epilepsy variants in the context of TSC. Specifically, we have identified a novel signal in SLC7A1 that may be functionally involved in pathways relevant to TSC and epilepsy. Our study highlights the need for further evaluation of genetic modifiers in TSC to aid in further understanding of epilepsy in TSC and improve outcomes.

Early Treatment with Vigabatrin Does Not Decrease Focal Seizures or Improve Cognition in Tuberous Sclerosis Complex: The PREVeNT Trial

OBJECTIVE

This study was undertaken to test the hypothesis that early vigabatrin treatment in tuberous sclerosis complex (TSC) infants improves neurocognitive outcome at 24 months of age.

METHODS

A phase IIb multicenter randomized double-blind placebo-controlled trial was conducted of vigabatrin at first epileptiform electroencephalogram (EEG) versus vigabatrin at seizure onset in infants with TSC. Primary outcome was Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) cognitive assessment score at 24 months. Secondary outcomes were prevalence of drug-resistant epilepsy, additional developmental outcomes, and safety of vigabatrin.

RESULTS

Of 84 infants enrolled, 12 were screen failures, 4 went straight to open label vigabatrin, and 12 were not randomized (normal EEG throughout). Fifty-six were randomized to early vigabatrin (n = 29) or placebo (n = 27). Nineteen of 27 in the placebo arm transitioned to open label vigabatrin, with a median delay of 44 days after randomization. Bayley-III cognitive composite scores at 24 months were similar for participants randomized to vigabatrin or placebo. Additionally, no significant differences were found between groups in overall epilepsy incidence and drug-resistant epilepsy at 24 months, time to first seizure after randomization, and secondary developmental outcomes. Incidence of infantile spasms was lower and time to spasms after randomization was later in the vigabatrin group. Adverse events were similar across groups.

INTERPRETATION

Preventative treatment with vigabatrin based on EEG epileptiform activity prior to seizure onset does not improve neurocognitive outcome at 24 months in TSC children, nor does it delay onset or lower the incidence of focal seizures and drug-resistant epilepsy at 24 months. Preventative vigabatrin was associated with later time to onset and lower incidence of infantile spasms. ANN NEUROL 2023.

Mild TSC Phenotype and Non-Penetrance Associated with a Frameshift Variant in TSC2 Prompts Caution in Evaluating Pathogenicity of Frameshift Variants

INTRODUCTION

Technological advances in genetic testing, particularly the adoption of noninvasive prenatal screening (NIPS) for single gene disorders such as tuberous sclerosis complex (TSC, OMIM# 613254), mean that putative/possible pathogenetic DNA variants can be identified prior to the appearance of a disease phenotype. Without a phenotype, accurate prediction of variant pathogenicity is crucial. Here, we report a TSC2 frameshift variant, NM_000548.5(TSC2):c.4255_4256delCA, predicted to result in nonsense-mediated mRNA decay (NMD) and cessation of TSC2 protein production and thus pathogenic according to ACMG criteria, identified by NIPS and subsequently detected in family members with few or no symptoms of TSC. Due to the lack of TSC-associated features in the family, we hypothesized that the deletion created a non-canonical 5' donor site resulting in cryptic splicing and a transcript encoding active TSC2 protein. Verifying the predicted effect of the variant was key to designating pathogenicity in this case and should be considered for other frameshift variants in other genetic disorders.

METHODS

Phenotypic information on the family members was collected via review of the medical records and patient reports. RNA studies were performed using proband mRNA isolated from blood lymphocytes for RT-PCR and Sanger sequencing. Functional studies were performed by transient expression of the TSC2 variant proteins in cultured cells, followed by immunoblotting.

RESULTS

No family members harboring the variant met any major clinical diagnostic criteria for TSC, though a few minor features non-specific to TSC were present. RNA studies supported the hypothesis that the variant caused cryptic splicing, resulting in an mRNA transcript with an in-frame deletion of 93 base pairs r.[4255_4256del, 4251_4343del], p.[(Gln1419Valfs*104), (Gln1419_Ser1449del)]. Expression studies demonstrated that the canonical function of the resulting truncated TSC2 p.Gln1419_Ser1449del protein product was maintained and similar to wildtype.

CONCLUSION

Although most frameshift variants are likely to result in NMD, the NM_000548.5(TSC2):c.4255_4256delCA variant creates a cryptic 5' splice donor site, resulting in an in-frame deletion that retains TSC2 function, explaining why carriers of the variant do not have typical features of TSC. The information is important for this family and others with the same variant. Equally important is the lesson that predictions can be inaccurate, and that caution should be used when designating frameshift variants as pathogenic, especially when phenotypic information to corroborate testing results is unavailable. Our work demonstrates that functional RNA- and protein-based confirmation of the effects of DNA variants improves molecular genetic diagnostics.

Prenatal diagnosis of tuberous sclerosis complex: Echocardiography, cranial magnetic resonance, and genetic testing of 40 cases with fetal cardiac tumors

Objective

To explore the relationship between Tuberous sclerosis complex (TSC) and cardiac tumors at our institution over the past five years and to evaluate the value of imaging technologies and genetic testing in the prenatal diagnosis of TSC.

Methods

Fetal echocardiography (FE) was performed in the whole population between 2016 and 2020. Fetuses detected with cardiac tumor(s) were included. Fetal cranial magnetic resonance imaging (MRI) and gene mutation tests were further examined. Those who declined genetic testing were excluded in the final analysis.

Results

A total of 40 fetuses were included in our study. There were 27 cases performed cranial magnetic resonance imaging (MRI) and the rest of 13 cases refused. Among 10 fetuses with cranial lesions detected by MRI, all of them were eventually diagnosed with TSC. And for 17 fetuses without cranial lesions, none of them were identified with a pathogenic variation in gene TSC1/2. The prevalence of TSC was significantly higher in the multiple tumors group than in the solitary group (9/20 vs. 2/20, P = 0.034). 11 fetuses had TSC1 (n = 3) or TSC2 (n = 8) causative or suspected causative mutations, of which 9 were sporadic mutations and 2 were familial mutations.

Conclusion

Fetal cranial MRI should be recommended to evaluate brain lesions, and genetic mutation should be examined, if possible, especially for those with multiple heart tumors. When typical cardiac tumors and cranial lesions are detected, the diagnosis of TSC can almost be made even without genetic mutation results.

Effect of mTOR Inhibitors in Epilepsy Treatment in Children with Tuberous Sclerosis Complex Under 2 Years of Age

INTRODUCTION

Mechanistic target of rapamycin (mTOR) inhibitors sirolimus and everolimus are an effective therapy for subependymal giant cell astrocytomas, cardiac rhabdomyomas, renal angiomyolipomas, and lymphangioleiomyomatosis associated with tuberous sclerosis complex (TSC). Everolimus was recently approved in the EU and the USA for the treatment of refractory focal-onset seizures. Despite frequent use of mTOR inhibitors, there are only a few studies on their effect on epilepsy control in children under 2 years of age. This study aims to assess the effect of adjunctive mTOR inhibitor treatment on seizure frequency in this age group.

METHODS

We performed retrospective data analysis of medical records of patients with TSC who initiated sirolimus or everolimus under the age of 2 years. Participants' antiseizure medication was adjusted according to their epilepsy control independently from mTOR inhibitor administration. The data was assessed separately for patients treated with mTOR inhibitors before and after the onset of seizures. We also compared the treatment group with a matched control group. The follow-up duration was up to 24 months.

RESULTS

Twenty-one patients with TSC from two clinical centers were included in the study. Nine participants had no history of seizures before mTOR inhibitor initiation. Twelve reported active epilepsy in the month prior to treatment initiation. Most patients treated preventively with mTOR inhibitors did not report active epilepsy at the end of their follow-up. In the second group, the mean frequency of seizures decreased with time. According to the comparative analysis, seizure control was better in the groups treated with mTOR inhibitors.

CONCLUSION

Patients with TSC treated with mTOR inhibitors demonstrated better seizure control than individuals without this treatment. Adjunctive pharmacotherapy with mTOR inhibitors appears to have a beneficial effect on epilepsy outcome in young children. Further prospective clinical trials should be conducted to determine the efficacy of mTOR inhibitors on epilepsy in patients with TSC under the age of 2 years.

Clinical seizure semiology is subtle and identification of seizures by parents is unreliable in infants with tuberous sclerosis complex

OBJECTIVE

The objectives of this study were to assess the accuracy of parental seizure detection in infants with antenatally diagnosed tuberous sclerosis complex (TSC), and to document the total seizure burden (clinical and subclinical) in those patients who met criteria for prolonged electroencephalography (EEG) recording.

METHODS

Consecutive infants at a single institution with antenatally diagnosed TSC who met criteria for prolonged video-EEG (vEEG) were recruited to this study. The vEEG data were reviewed and when a seizure was identified on EEG, the video and audio recording was assessed for evidence of clinical seizure and, if present, whether there was evidence of parent seizure identification.

RESULTS

Nine infants were enrolled, for whom 674 focal seizures were identified in eight of nine patients across 24 prolonged vEEG recordings, with vEEG total duration of 634 h 49 min (average seizure frequency of 1 focal seizure/h). Only 220 of 674 (32.6%) were clinical seizures, 395 of 674 (58.6%) were subclinical seizures, and 59 of 674 seizures could not be classified. Only 63 of 220 clinical seizures (28.6%) were identified by parents, with 157 of 220 (71.4%) not identified. Thirty clusters of epileptic spasms were detected in one patient. At least one clinical epileptic spasm occurred in 2 of 30 clusters (6.7%), 24 of 30 clusters of epileptic spasms (80%) were electrographic only, and classification was uncertain for 4 of 30 clusters (13.3%). No clinical epileptic spasms were detected by parents. Clinical seizure frequency was significantly underestimated by parents for all patients.

SIGNIFICANCE

This study demonstrates that in infants with TSC who met criteria for prolonged vEEG, (1) parents significantly under recognize total clinical seizure count, (2) parents fail to identify epileptic spasms, and (3) seizure frequency is high. This highlights that epilepsy treatment decisions should not be based solely on parental clinical seizure identification. Prolonged vEEG monitoring may have an important role in the routine epilepsy care of infants with TSC, as demonstrating undetected high clinical seizure frequency may allow improved epilepsy management decisions.

Clinical profile of tuberous sclerosis complex patients with and without epilepsy: a need for awareness for early diagnosis

BACKGROUND

Tuberous sclerosis complex (TSC) is a multisystemic disorder. Its clinical features manifest differently in several organs, prompting the need for better knowledge.

OBJECTIVE

The goal of the present study is to evaluate the neurological findings of TSC, such as cerebral lesions and epilepsy, and to raise awareness of non-neurological findings that could contribute to an earlier diagnosis and treatment.

METHODS

This was a natural history study of patients with a definitive diagnosis of TSC who were referred to a specialized outpatient clinic and followed-up for 2 years with clinical and radiological exams.

RESULTS

A total of 130 TSC patients (59 males [45.4%], mean age 20.4 years old [1 to 56 years old]); 107 patients (82.3%) were diagnosed with epilepsy. Seizures predominantly began at < 1 year old (72.8%); focal seizures predominated (86.9%); epileptic spasms occurred in 34.5% of patients, and refractory epilepsy was present in 55.1%. Neuropsychiatric disorders, cortical tubers and cerebellar tubers were significantly more frequent in the epilepsy group. Moreover, rhabdomyomas were significantly more frequent in the epilepsy group (p = 0.044), while lymphangioleiomyomatosis was significantly less frequent in the epilepsy group (p = 0.009). Other non-neurological findings did not differ significantly between the groups with and without epilepsy.

CONCLUSIONS

The present study of TSC patients demonstrated the predominantly neurological involvement and significantly higher proportion of TSC-associated neuropsychiatric disorders in the epilepsy group. Higher proportions of cortical and cerebellar tubers may be a risk factor for epilepsy and neurodevelopmental disorders.

The autism spectrum disorder phenotype in children with tuberous sclerosis complex: A systematic review and meta-analysis

AIM

To investigate the phenotype in autistic children with tuberous sclerosis complex (TSC), specifically autism spectrum disorder (ASD) severity and characteristics, intellectual ability, adaptive and executive function, language skills, attention-deficit/hyperactivity disorder features, and internalizing and externalizing behaviours.

METHOD

MEDLINE, Embase, and the Cochrane Library were searched up to March 2021. Studies that investigated predefined phenotypic factors in children with TSC-ASD were included according to the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) guidelines. Two authors independently reviewed titles, abstracts, full texts, and extracted the data. Risk of bias and GRADE assessments were completed.

RESULTS

Thirty-four studies with 3160 children with TSC, 30% with ASD, were included. Meta-analysis found that 90% (95% confidence interval 86%-94%) of children with TSC-ASD have an intellectual disability. There was some evidence to suggest that young children with TSC-ASD and idiopathic ASD have a similar pattern of severity and behaviour. Overall, data about phenotypic characteristics were limited.

INTERPRETATION

A greater proportion of children with TSC-ASD are reported to have an intellectual disability than children with idiopathic ASD. Early intervention should consider the needs of children with a high likelihood of intellectual disability. Research is needed to better understand the impacts of intellectual disability and other co-occurring difficulties on adaptive function, participation, and quality of life in TSC-ASD.

WHAT THIS PAPER ADDS

Most children with tuberous sclerosis complex (TSC) and autism spectrum disorder (ASD) have an intellectual disability. TSC-ASD early intervention planning should consider the high likelihood of intellectual disability. Quality of life and the functional impact of intellectual disability in TSC-ASD are not understood. Little is known about co-occurring difficulties in TSC-ASD.

Epilepsy and Language Development in 8–36-Month-Old Toddlers with Tuberous Sclerosis Complex

This paper aimed to assess language development in infants and toddlers with tuberous sclerosis complex (TSC) and epilepsy, which increase the risk of autism spectrum disorder. We assessed language development in 61 patients with TSC at 8–36 months using a standardized Speech Development and Communication Inventory tool. The results showed differences in outcomes due to the duration of the seizures and the number of drugs (pFDR = 0.007 **—pFDR = 0.037 *). Children with TSC with longer epilepsy duration and receiving more antiepileptic drugs have a greater risk of language development delay.

Genetic pathogenesis of the epileptogenic lesions in Tuberous Sclerosis Complex: Therapeutic targeting of the mTOR pathway

Tuberous sclerosis complex (TSC) is a genetic multisystem disease due to the mutation in one of the two genes TSC1 and TSC2, affecting several organs and systems and carrying a significant risk of early onset and refractory seizures. The pathogenesis of this complex disorder is now well known, with most of TSC-related manifestations being a consequence of the overactivation of the mammalian Target of Rapamycin (mTOR) complex. The discovery of this underlying mechanism paved the way for the use of a class of drugs called mTOR inhibitors including rapamycin and everolimus and specifically targeting this pathway. Rapamycin has been widely used in different animal models of TSC-related epilepsy and proved to be able not only to suppress seizures but also to prevent the development of epilepsy, thus demonstrating an antiepileptogenic potential. In some models, it also showed some benefit on neuropsychiatric manifestations associated with TSC. Everolimus has recently been approved by the US Food and Drug Administration and the European Medical Agency for the treatment of refractory seizures associated with TSC starting from the age of 2 years. It demonstrated a clear benefit when compared to placebo on reducing the frequency of different seizure types and exerting a higher effect in younger children. In conclusion, mTOR cascade can be a potentially major cause of TSC-associated epilepsy and neurodevelopmental disability, and additional research should investigate if early suppression of abnormal mTOR signal with mTOR inhibitors before seizure onset can be a more efficient approach and an effective antiepileptogenic and disease-modifying strategy in infants with TSC.

Antiepileptic Effect and Safety Profile of Rapamycin in Pediatric Patients With Tuberous Sclerosis Complex

Background

Epilepsy develops in 70–90% of children with Tuberous Sclerosis Complex (TSC) and is often resistant to medication. Treatment with mTOR pathway inhibitors is an important therapeutic option in drug-resistant epilepsy associated with TSC. Our study evaluated the antiepileptic effect of rapamycin in the pediatric population of patients diagnosed with TSC.

Methods

This single center, open-label study evaluated safety and anti-epileptic efficacy of 12 months of rapamycin treatment in 32 patients aged from 11 months to 14 years with drug-resistant TSC- associated epilepsy.

Results

After the first 6 months of treatment, the improvement in seizure frequency, defined as at least a 50% reduction in the number of seizures per week compared to baseline, was seen in 18 individuals (56.25%). We observed no change in 12 individuals (37.5%) and worsening, defined as increase in the number of seizures—in 2 patients (6.25%). The overall improvement defined as at least a 50% reduction in seizure frequency was found in 65.6% of all patients after 12 months with 28% of patients obtaining complete remission. Another five patients experienced at least an 80% reduction in the frequency of seizures. Concomitant treatment with vigabatrin, and to a much lesser extent topiramate and levetiracetam, was an additional favorable prognostic factor for the success of the therapy. A linear relationship between the cumulative dose of rapamycin and its therapeutic effect was observed. The safety profile of the drug was satisfactory. In none of the observed cases did the adverse events reach the level that required withdrawal of the rapamycin treatment. The reason for dropouts was insufficient drug efficacy in 3 cases.

Conclusions

Long-term use of rapamycin, especially in combination with vigabatrin, might be a beneficial therapeutic option in the treatment of drug-resistant epilepsy in children with TSC.

Focal Epilepsy in Children With Tuberous Sclerosis Complex: Does Vigabatrin Control Focal Seizures?

We evaluated the efficacy and safety of vigabatrin in focal epilepsy associated with tuberous sclerosis complex by retrospectively reviewing patients with focal epilepsy and tuberous sclerosis complex treated with vigabatrin at a pediatric epilepsy center over an 8-year period. Of 85 patients, 20 (23.5%) were seizure-free for >12 months, 45 (52.9%) were responders (≥50% seizure reduction), and 20 (23.5%) were nonresponders. The median age (in months) at seizure onset in the seizure-free group (median, 15; interquartile range [IQR], 6-23.3) was higher than that of responders (median, 5; IQR, 3-14) and nonresponders (median, 6; IQR, 2-12). Fewer patients in the seizure-free group had calcification in their largest tubers, but the presence of tuber calcification did not differ among groups. Vigabatrin is more likely to result in seizure freedom in children with tuberous sclerosis complex who have later infantile onset of focal seizures and no calcification in their largest tuber.

Current role of surgery for tuberous sclerosis complex‐associated epilepsy

Tuberous sclerosis complex (TSC) is a rare multisystem, autosomal dominant neurocutaneous syndrome in which epilepsy is the most common of several neurological and psychiatric manifestations. Around two thirds of patients develop drug‐resistant epilepsy for whom surgical resection of epileptogenic foci is indicated when seizures remain inadequately controlled following trial of two antiseizure medications. The challenge with presurgical and surgical approaches with patients with TSC is overcoming the complexity from the number of tubers and the multiplex epileptogenic network forming the epileptogenic zone. Data suggest that seizure freedom is achieved by 55%–60% of patients, but predictive factors for success have remained elusive, which makes for unconfident selection of surgical candidates. This article presents three different cases as illustrations of the potential challenges faced when assessing the suitability of TSC patients for epilepsy surgery.

The research landscape of tuberous sclerosis complex-associated neuropsychiatric disorders (TAND)-a comprehensive scoping review

BACKGROUND

Tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND) is an umbrella term for the behavioural, psychiatric, intellectual, academic, neuropsychological and psychosocial manifestations of TSC. Although TAND affects 90% of individuals with TSC during their lifetime, these manifestations are relatively under-assessed, under-treated and under-researched. We performed a comprehensive scoping review of all TAND research to date (a) to describe the existing TAND research landscape and (b) to identify knowledge gaps to guide future TAND research.

METHODS

The study was conducted in accordance with stages outlined within the Arksey and O'Malley scoping review framework. Ten research questions relating to study characteristics, research design and research content of TAND levels and clusters were examined.

RESULTS

Of the 2841 returned searches, 230 articles published between 1987 and 2020 were included (animal studies = 30, case studies = 47, cohort studies = 153), with more than half published since the term TAND was coined in 2012 (118/230; 51%). Cohort studies largely involved children and/or adolescents (63%) as opposed to older adults (16%). Studies were represented across 341 individual research sites from 45 countries, the majority from the USA (89/341; 26%) and the UK (50/341; 15%). Only 48 research sites (14%) were within low-middle income countries (LMICs). Animal studies and case studies were of relatively high/high quality, but cohort studies showed significant variability. Of the 153 cohort studies, only 16 (10%) included interventions. None of these were non-pharmacological, and only 13 employed remote methodologies (e.g. telephone interviews, online surveys). Of all TAND clusters, the autism spectrum disorder-like cluster was the most widely researched (138/230; 60%) and the scholastic cluster the least (53/200; 27%).

CONCLUSIONS

Despite the recent increase in TAND research, studies that represent participants across the lifespan, LMIC research sites and non-pharmacological interventions were identified as future priorities. The quality of cohort studies requires improvement, to which the use of standardised direct behavioural assessments may contribute. In human studies, the academic level in particular warrants further investigation. Remote technologies could help to address many of the TAND knowledge gaps identified.

Could prevention of infantile spasms have been possible in a historical cohort of 31 tuberous sclerosis patients?

Efforts to prevent epilepsy in infants with tuberous sclerosis complex (TSC) has been the focus of EPISTOP.

PURPOSE

The present study was carried out to evaluate whether prevention could have been realistic.

METHODS

A retrospective analysis by hospital chart review of 31 patients with TSC and infantile spasms (practically all patients) admitted to two tertiary hospitals, Children's Hospital, University of Helsinki and Kuopio in 1980-2000. Clinical history, early cognitive development, early clinical signs of TSC, clinical signs of suspicious seizures, first seizures and EEG, response to adrenocorticotropic hormone (ACTH) therapy, EEG and brain imaging were evaluated.

RESULTS

Early development prior the spasms was apparently normal in 25 (80%). The first EEG ever performed for a child showed hypsarrhythmia in 16 (51%) or modified hypsarrhythmia in 10 (32%). Treatment lag was short (0-4, mean 2 weeks) and the primary response to ACTH favorable in 19 (64%). Etiological diagnostic workup of IS revealed TSC. In one single case (3%) the diagnosis of TSC could be made at birth due to a congenital cardiac rhabdomyoma. Three other rhabomyomas were diagnosed later. In brain imaging, subependymal periventricular calcifications or hypodense areas were seen in every patient at onset of IS. Other organ manifestations of TSC were retinal phakomas (6), polycystic kidneys (2), and renal angiolipomatosis (1).

CONCLUSIONS

Preventive treatment of epileptic discharges could have been possible in a single case of neonatal rhabdomyoma suggesting that preventive treatment is challenging in everyday practice. The main obstacle is the delay of TSC diagnosis.

Pharmacotherapy for Seizures in Tuberous Sclerosis Complex

Epilepsy is one of the main symptoms affecting the lives of individuals with tuberous sclerosis complex (TSC), causing a high rate of morbidity. Individuals with TSC can present with various types of seizures, epilepsies, and epilepsy syndromes that can coexist or appear in relation to age. Focal epilepsy is the most frequent epilepsy type with two developmental and epileptic encephalopathies: infantile spasms syndrome and Lennox-Gastaut syndrome. Active screening and early management of epilepsy is recommended in individuals with TSC to limit its consequences and its impact on quality of life, cognitive outcome and the economic burden of the disease. The progress in the knowledge of the mechanisms underlying epilepsy in TSC has paved the way for new concepts in the management of epilepsy related to TSC. In addition, we are moving from traditional "reactive" and therapeutic choices with current antiseizure medications used after the onset of seizures, to a proactive approach, aimed at predicting and preventing epileptogenesis and the onset of epilepsy with vigabatrin, and to personalized treatments with mechanistic therapies, namely mechanistic/mammalian target of rapamycin inhibitors. Indeed, epilepsy linked to TSC is one of the only epilepsies for which a predictive and preventive approach can delay seizure onset and improve seizure response. However, the efficacy of such interventions on long-term cognitive and psychiatric outcomes is still under investigation.

What is the effect of delays in access to specialist epilepsy care on patient outcomes? A systematic review and meta-analysis

OBJECTIVE

To determine the association between delays in access to specialist epilepsy care and patient outcomes.

METHODS

Three databases were searched using eligibility criteria related to the concepts of timely access, epilepsy, and clinical outcome. Comparative data on patient outcomes by time to treatment was required for inclusion. Studies were selected independently by two researchers who reviewed title/abstract, then full text articles. Data were extracted and risk of bias was evaluated. Results were synthesized in random effects model meta-analyses, and strength of the body of evidence was evaluated. Descriptive analysis was conducted for studies not included in meta-analyses.

RESULTS

Thirty-five studies, reported in 40 papers, were included. The studies investigated impact of delays in diagnosis, commencement of medication, or surgery for children and adults. Early diagnosis and access to specialist neurology care was associated with improvements in seizure status, development, and/or intelligence quotients. Meta-analyses provided low to high certainty evidence of increased odds of improved seizure outcome with early commencement of medication depending on follow-up period and individual risk factors. There was moderate certainty evidence that people with favorable seizure outcomes wait less time (MD 2.8 years, 95% CI 1.7-3.9) for surgery compared to those with unfavorable outcomes.

SIGNIFICANCE

This review provides evidence that earlier access to specialist epilepsy care for diagnosis, commencement of medication, and surgery is associated with better patient outcomes.

Factors associated with autism spectrum disorder in children with tuberous sclerosis complex: a systematic review and meta-analysis

AIM

To investigate associations between clinical factors and the development of autism spectrum disorder (ASD) in children with tuberous sclerosis complex (TSC), specifically seizures, electroencephalogram abnormalities, tubers and other neurostructural abnormalities, and genetic factors.

METHOD

MEDLINE, Embase, PubMed, the Cochrane Library, and Web of Science were searched until January 2019. Studies that considered the predefined factors for development of ASD in children with TSC were included, following PRISMA-P guidelines. Two authors independently reviewed titles, abstracts, and full texts, extracted data, and assessed risk of bias.

RESULTS

Forty-two studies with 3542 children with TSC were included. ASD was associated with a history of seizures (odds ratio [OR] 3.79, 95% confidence interval [CI] 1.77-8.14), infantile spasms compared with other seizure types (OR 3.04, 95% CI 2.17-4.27), onset of any seizure type during infancy (OR 2.65, 95% CI 1.08-6.54), and male sex (OR 1.62, 95% CI 1.23-2.14). There was no association with tuber number, tuber location, or genotype.

INTERPRETATION

While a causal link between seizures and ASD in children with TSC cannot be inferred, a strong association between seizures and ASD in children with TSC, particularly with seizure onset during infancy and specifically infantile spasms, is present. Children with TSC and infant-onset seizures should be monitored for emerging features of ASD. What this paper adds Seizures and autism spectrum disorder (ASD) strongly associate in children with tuberous sclerosis complex (TSC). Infant-onset seizures and infantile spasms are particularly strongly associated with ASD in TSC.

Prescription patterns of antiseizure drugs in tuberous sclerosis complex (TSC)-associated epilepsy: a multicenter cohort study from Germany and review of the literature

OBJECTIVE

Seizures are a primary and early disease manifestation of Tuberous Sclerosis Complex (TSC). We aimed to describe the age-stratified patterns of antiseizure drug (ASD) treatments among children, adolescents, and adults with TSC in Germany. Additionally, we reviewed real-world and clinical study evidence regarding ASD utilization in patients with TSC.

METHODS

We evaluated the pattern of routine ASD use and everolimus prescriptions based on a 2019 multicenter survey of 268 individuals with TSC-associated epilepsy. We contextualized the results with a structured review of real-world and clinical study evidence.

RESULTS

TSC-associated epilepsy treatment comprises a wide variety of ASDs. In this German sample, the majority of patients were treated with polytherapy, and lamotrigine (34.7%), valproate (32.8%), oxcarbazepine (28.7%), vigabatrin (19.0%), and levetiracetam (17.9%) were identified as the most-commonly used ASDs. In addition, everolimus was used by 32.5% of patients. In adherence to current TSC guidelines, the disease-modifying ASD vigabatrin was widely used in children (58% below the age of 5 years), whereas treatment in adults did not necessarily reflect guideline preference for (partial) GABAergic ASDs.

CONCLUSIONS

The selection of ASDs for patients with TSC-associated epilepsy follows well-evaluated recommendations, including the guidelines regarding vigabatrin use in children. Several characteristics, such as the comparatively high frequency of valproate use and polytherapy, reflect the severity of TSC-associated epilepsy.

TSC1 and TSC2: Tuberous Sclerosis Complex and Its Related Epilepsy Phenotype

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a multisystemic involvement. In TSC, reduced function of TSC1 and TSC2 genes products (hamartin and tuberin, respectively) leads to an hyperactivation of the mechanistic target of rapamycin (mTOR) pathway and to a consequent cell growth dysregulation. In TSC patients, neurological and neuropsychiatric manifestations, especially epilepsy and neuropsychiatric comorbidities such as autism or intellectual disability, represent the most disabling features. In particular, epilepsy occurrs up to 80% of patients, is often drug resistant and is frequently associated with neurological impairment. Due to the burden of this morbidity, different treatment strategies have been proposed with the purpose to make patients epilepsy free, such as the use of different antiepileptic drugs like vigabatrin, carbamazepine, valproic acid, and levetiracetam. More recently, a mTOR inhibitor (i.e. everolimus) has showed promising results in terms of seizures reduction.

Current Approaches and Future Directions for the Treatment of mTORopathies

The mechanistic target of rapamycin (mTOR) is a kinase at the center of an evolutionarily conserved signaling pathway that orchestrates cell growth and metabolism. mTOR responds to an array of intra- and extracellular stimuli and in turn controls multiple cellular anabolic and catabolic processes. Aberrant mTOR activity is associated with numerous diseases, with particularly profound impact on the nervous system. mTOR is found in two protein complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2), which are governed by different upstream regulators and have distinct cellular actions. Mutations in genes encoding for mTOR regulators result in a collection of neurodevelopmental disorders known as mTORopathies. While these disorders can affect multiple organs, neuropsychiatric conditions such as epilepsy, intellectual disability, and autism spectrum disorder have a major impact on quality of life. The neuropsychiatric aspects of mTORopathies have been particularly challenging to treat in a clinical setting. Current therapeutic approaches center on rapamycin and its analogs, drugs that are administered systemically to inhibit mTOR activity. While these drugs show some clinical efficacy, adverse side effects, incomplete suppression of mTOR targets, and lack of specificity for mTORC1 or mTORC2 may limit their utility. An increased understanding of the neurobiology of mTOR and the underlying molecular, cellular, and circuit mechanisms of mTOR-related disorders will facilitate the development of improved therapeutics. Animal models of mTORopathies have helped unravel the consequences of mTOR pathway mutations in specific brain cell types and developmental stages, revealing an array of disease-related phenotypes. In this review, we discuss current progress and potential future directions for the therapeutic treatment of mTORopathies with a focus on findings from genetic mouse models.

Developmental and epileptic encephalopathies: what we do and do not know

Developmental encephalopathies, including intellectual disability and autistic spectrum disorder, are frequently associated with infant epilepsy. Epileptic encephalopathy is used to describe an assumed causal relationship between epilepsy and developmental delay. Developmental encephalopathies pathogenesis more independent from epilepsy is supported by the identification of several gene variants associated with both developmental encephalopathies and epilepsy, the possibility for gene-associated developmental encephalopathies without epilepsy, and the continued development of developmental encephalopathies even when seizures are controlled. Hence, 'developmental and epileptic encephalopathy' may be a more appropriate term than epileptic encephalopathy. This update considers the best studied 'developmental and epileptic encephalopathy' gene variants for illustrative support for 'developmental and epileptic encephalopathy' over epileptic encephalopathy. Moreover, the interaction between epilepsy and developmental encephalopathies is considered with respect to influence on treatment decisions. Continued research in genetic testing will increase access to clinical tests, earlier diagnosis, better application of current treatments, and potentially provide new molecular-investigated treatments.

Prevention of Epilepsy in Infants with Tuberous Sclerosis Complex in the EPISTOP Trial

OBJECTIVE

Epilepsy develops in 70 to 90% of children with tuberous sclerosis complex (TSC) and is often resistant to medication. Recently, the concept of preventive antiepileptic treatment to modify the natural history of epilepsy has been proposed. EPISTOP was a clinical trial designed to compare preventive versus conventional antiepileptic treatment in TSC infants.

METHODS

In this multicenter study, 94 infants with TSC without seizure history were followed with monthly video electroencephalography (EEG), and received vigabatrin either as conventional antiepileptic treatment, started after the first electrographic or clinical seizure, or preventively when epileptiform EEG activity before seizures was detected. At 6 sites, subjects were randomly allocated to treatment in a 1:1 ratio in a randomized controlled trial (RCT). At 4 sites, treatment allocation was fixed; this was denoted an open-label trial (OLT). Subjects were followed until 2 years of age. The primary endpoint was the time to first clinical seizure.

RESULTS

In 54 subjects, epileptiform EEG abnormalities were identified before seizures. Twenty-seven were included in the RCT and 27 in the OLT. The time to the first clinical seizure was significantly longer with preventive than conventional treatment [RCT: 364 days (95% confidence interval [CI] = 223-535) vs 124 days (95% CI = 33-149); OLT: 426 days (95% CI = 258-628) vs 106 days (95% CI = 11-149)]. At 24 months, our pooled analysis showed preventive treatment reduced the risk of clinical seizures (odds ratio [OR] = 0.21, p = 0.032), drug-resistant epilepsy (OR = 0.23, p = 0.022), and infantile spasms (OR = 0, p < 0.001). No adverse events related to preventive treatment were noted.

INTERPRETATION

Preventive treatment with vigabatrin was safe and modified the natural history of seizures in TSC, reducing the risk and severity of epilepsy. ANN NEUROL 2021;89:304-314.

Approach to Preventive Epilepsy Treatment in Tuberous Sclerosis Complex and Current Clinical Practice in 23 Countries

Tuberous sclerosis complex (TSC) is associated with a high risk of early-onset epilepsy and developmental delay. Recently, EEG monitoring in infants with TSC and preventive antiepileptogenic treatment have been proposed to improve epilepsy and neurodevelopmental outcome. We explored how recent studies and recommendations regarding EEG monitoring and preventive epilepsy treatment have influenced the clinical practice of epilepsy management among children with TSC.

METHODS

A survey on the epilepsy management approach in infants with TSC was sent by e-mail to 165 clinicians who actively participated in TSC international research conferences in years 2016 - 2019. Additionally, the e-mail addresses of TSC referral centers were collected from national TSC organizations. The survey was also distributed in the American Epilepsy Society newsletter. Only responses from centers providing neurological care for children with TSC were included in the study.

RESULTS

Sixty-one responses from 23 countries were analyzed. Sixty respondents answered questions concerning infants, and 57 of 60 respondents (95%) perform at least one EEG study before epilepsy onset and 42 (70.0%) conduct regular EEG monitoring. Most of the clinicians perform video EEG (42/61, 68.8%). Overall, 51.7% of respondents, mostly from Europe, Australia, and South America, endorse preventive antiepileptic treatment in infants with TSC. Vigabatrin is a preferred drug in patients younger than two years old for both focal (61.7%) and generalized (56.7%) seizures.

CONCLUSIONS

Despite the lack of published results of randomized trials, the concepts of preseizure EEG monitoring and epilepsy prevention are already being implemented in the majority of surveyed centers.

A case of TSC2-PKD1 contiguous deletion syndrome: Clinical features and effective treatment for epilepsy

Polycystic kidney disease with Tuberous sclerosis is a disease caused by the deletions of the TSC2-PKD1 gene. The disease is rarely reported and the characterized manifestation is severe polycystic kidney growth. The diagnosis can be made by molecular analysis. We report the first case of PKDTS discovered in infancy in China with typical neurological and renal manifestations. The patient has infantile spasm, polycystic kidney, skin damage, hypertension, and hematuria after infection. After effective treatment of Rapamycin, the seizures were completely controlled. There was not been any renal function damage in the patient. At the same time, we review the related literature and further elaborate on the variety of clinical manifestations, treatment, and prognosis.

Epilepsy Risk Prediction Model for Patients With Tuberous Sclerosis Complex

BACKGROUND

Individuals with tuberous sclerosis complex are at increased risk of epilepsy. Early seizure control improves developmental outcomes, making identifying at-risk patients critically important. Despite several identified risk factors, it remains difficult to predict. The purpose of the study was to evaluate the combined risk prediction of previously identified risk factors for epilepsy in individuals with tuberous sclerosis complex.

METHODS

The study group (n = 333) consisted of individuals with tuberous sclerosis complex who were enrolled in the Tuberous Sclerosis Complex Autism Center of Excellence Research Network and UT TSC Biobank. The outcome was defined as having an epilepsy diagnosis. Potential risk factors included sex, TSC genotype, and tuber presence. Logistic regression was used to calculate the odds ratio and P value for the association between each variable and epilepsy. A clinical risk prediction model incorporating all risk factors was built. Area under the curve was calculated to characterize the full model's ability to discriminate individuals with tuberous sclerosis complex with and without epilepsy.

RESULTS

The strongest risk for epilepsy was presence of tubers (95% confidence interval: 2.39 to 10.89). Individuals with pathogenic TSC2 variants were three times more likely (95% confidence interval: 1.55 to 6.36) to develop seizures compared with those with tuberous sclerosis complex from other causes. The combination of risk factors resulted in an area under the curve 0.73.

CONCLUSIONS

Simple characteristics of patients with tuberous sclerosis complex can be combined to successfully predict epilepsy risk. A risk assessment model that incorporates sex, TSC genotype, protective TSC2 missense variant, and tuber presence correctly predicts epilepsy in 73% of patients with tuberous sclerosis complex.

Prediction of Neurodevelopment in Infants With Tuberous Sclerosis Complex Using Early EEG Characteristics

Tuberous Sclerosis Complex (TSC) is a multisystem genetic disorder with a high risk of early-onset epilepsy and a high prevalence of neurodevelopmental comorbidities, including intellectual disability and autism spectrum disorder (ASD). Therefore, TSC is an interesting disease model to investigate early biomarkers of neurodevelopmental comorbidities when interventions are favourable. We investigated whether early EEG characteristics can be used to predict neurodevelopment in infants with TSC. The first recorded EEG of 64 infants with TSC, enrolled in the international prospective EPISTOP trial (recorded at a median gestational age 42 4/7 weeks) was first visually assessed. EEG characteristics were correlated with ASD risk based on the ADOS-2 score, and cognitive, language, and motor developmental quotients (Bayley Scales of Infant and Toddler Development III) at the age of 24 months. Quantitative EEG analysis was used to validate the relationship between EEG background abnormalities and ASD risk. An abnormal first EEG (OR = 4.1, p-value = 0.027) and more specifically a dysmature EEG background (OR = 4.6, p-value = 0.017) was associated with a higher probability of ASD traits at the age of 24 months. This association between an early abnormal EEG and ASD risk remained significant in a multivariable model, adjusting for mutation and treatment (adjusted OR = 4.2, p-value = 0.029). A dysmature EEG background was also associated with lower cognitive (p-value = 0.029), language (p-value = 0.001), and motor (p-value = 0.017) developmental quotients at the age of 24 months. Our findings suggest that early EEG characteristics in newborns and infants with TSC can be used to predict neurodevelopmental comorbidities.

Medical treatment of tuberous sclerosis-related epilepsy

Epilepsy is one of the most frequent CNS manifestations of tuberous sclerosis, and for most patients, it is the major debilitating factor. In up to 70% of the cases, the epilepsy is refractory and usually associated with significant behavioral as well as developmental consequences. Therefore, controlling seizures is one of the biggest medical and surgical challenges. Understanding the cellular mechanism involved in the disease empowered targeted research aimed toward early intervention in the epileptogenicity process. In this review, we present an update on the pharmacological treatments in tuberous sclerosis-related epilepsy.

Developmental outcomes in children/adolescents and one adult with tuberous sclerosis complex (TSC) and refractory epilepsy treated with everolimus

This prospective observational study focuses on developmental outcomes in the treatment of tuberous sclerosis complex (TSC) with everolimus (EVO). Fourteen children/adolescents aged 1.7-13.07 and one adult aged 31 years, all with TSC and refractory epilepsy participated. All were treated with EVO for 3-70 months (md: 37). Development/adaptive functioning were evaluated at baseline with follow-up in 11 patients; all patients were assessed during the course of treatment. Our exploratory analyses included factors contributing to developmental impairment and change from baseline to last evaluation. The majority of patients showed severe developmental impairment (86%). Patients with a higher age at inclusion, duration of epilepsy, and number of previous antiepileptic drugs (AEDs) showed lower developmental levels. Earlier onset of epilepsy and a higher number of current AEDs were associated with worse adaptive functioning. At their last examination, four patients were seizure-free (27%), and four experienced a reduction of seizures >50% (27%). With treatment, (slight) increase was seen in absolute values of developmental age (DA) regarding both development and adaptive functioning. Yet, when accounting for age, decrease was seen in both assessments. While developmental disorders were prominent, we observed an overall progression at a slower pace. Despite a positive effect on seizure occurrence, treatment with EVO did not reverse developmental problems in the observation period of this study.

Tuberous Sclerosis Complex as Disease Model for Investigating mTOR-Related Gliopathy During Epileptogenesis

Tuberous sclerosis complex (TSC) represents the prototypic monogenic disorder of the mammalian target of rapamycin (mTOR) pathway dysregulation. It provides the rational mechanistic basis of a direct link between gene mutation and brain pathology (structural and functional abnormalities) associated with a complex clinical phenotype including epilepsy, autism, and intellectual disability. So far, research conducted in TSC has been largely neuron-oriented. However, the neuropathological hallmarks of TSC and other malformations of cortical development also include major morphological and functional changes in glial cells involving astrocytes, oligodendrocytes, NG2 glia, and microglia. These cells and their interglial crosstalk may offer new insights into the common neurobiological mechanisms underlying epilepsy and the complex cognitive and behavioral comorbidities that are characteristic of the spectrum of mTOR-associated neurodevelopmental disorders. This review will focus on the role of glial dysfunction, the interaction between glia related to mTOR hyperactivity, and its contribution to epileptogenesis in TSC. Moreover, we will discuss how understanding glial abnormalities in TSC might give valuable insight into the pathophysiological mechanisms that could help to develop novel therapeutic approaches for TSC or other pathologies characterized by glial dysfunction and acquired mTOR hyperactivation.

Autism and Epilepsy in Patients With Tuberous Sclerosis Complex

Introduction: Individuals with Tuberous Sclerosis Complex (TSC) are at increased risk of developing both epilepsy and autism spectrum disorder (ASD), but the relationship between these conditions is little understood. We reviewed published reports to elucidate the relationship between ASD, epilepsy, and TSC, and to define the genetic and neurological risk factors. Methods: Articles (January 2004-May 2019) were identified via PubMed, EMBASE, and CENTRAL databases. Article inclusion required report on individuals with TSC-associated ASD and epilepsy with prevalence, odds ratio, or rate report on the comorbidity of ASD in epileptic patients due to TSC. Results: A total of 841 abstracts were identified in the original search. Thirty-six articles were included, which identified study populations, ASD measures used, and study confounders as bias factors. This review included 2,666 TSC patients, with a mean age of 15.9 years (range 1.94-30.3 years). The percentage of TSC patients with epilepsy and autism was 33.7%. Patients with TSC and autism showed more frequent seizures and earlier epilepsy onset than TSC patients without autism. ASD and intractable epilepsy were both predicted by a higher number of areas with dysplastic features revealed in brain MR scans. ASD, the onset of seizures in children <2 years of age, and >3 tubers have all been associated with an increased risk of refractory epilepsy in TSC patients. However, the direction of the relationship is not clear because a history of epilepsy, or infantile spasms in patients with TSC is also associated with an increased likelihood of ASD. Overall, 73.2% of patients carried TSC2 genetic variant and, among patients with TSC and autism, the percentage of TSC2 individuals was 85.6%. Conclusions: The complex interrelationship between TSC, autism, and epilepsy, coupled with limited knowledge on the neurobiological basis for the interrelationship, limits overall understanding and opportunities for management. The results of this review highlight the need for early identification and management to optimize favorable outcomes in the most vulnerable individuals with TSC. Regardless of whether studies are considered individually or collectively, interpretation is made difficult due to the differences between the studies, most notably between methods and diagnostic criteria used to assess intellectual ability.

Is autism driven by epilepsy in infants with Tuberous Sclerosis Complex?

Objective

To evaluate the relationship between age at seizure onset and neurodevelopmental outcome at age 24 months in infants with TSC, as well as the effect on neurodevelopmental outcome of early versus conventional treatment of epileptic seizures with vigabatrin (80–150 mg/kg/day).

Methods

Infants with TSC, aged ≤4 months and without previous seizures were enrolled in a prospective study and closely followed with monthly video EEG and serial standardized neurodevelopmental testing (Bayley Scales of Infant Development and Autism Diagnostic Observation Schedule).

Results

Eighty infants were enrolled. At the age of 24 months testing identified risk of Autism Spectrum Disorder (ASD) in 24/80 children (30.0%), and developmental delay (DD) in 26/80 (32.5%). Children with epilepsy (51/80; 63.8%) had a higher risk of ASD (P = 0.02) and DD (P = 0.001). Overall, no child presented with moderate or severe DD at 24 months (developmental quotient < 55). In 20% of children abnormal developmental trajectories were detected before the onset of seizures. Furthermore, 21% of all children with risk of ASD at 24 months had not developed seizures at that timepoint. There was no significant difference between early and conventional treatment with respect to rate of risk of ASD (P = 0.8) or DD (P = 0.9) at 24 months.

Interpretation

This study confirms a relationship between epilepsy and risk of ASD/DD. However, in this combined randomized/open label study, early treatment with vigabatrin did not alter the risk of ASD or DD at age 2 years.

Tuberous sclerosis complex associated intracranial lesion found by antenatal ultrasound

Tuberous sclerosis complex (TSC) is characterized by the growth of benign tumors in the skin, brain, kidneys, lung and heart [1]. Prognosis is mostly determined by the extent of brain involvement as tumors in the brain lead to seizures, cognitive impairment and behavioral problems. Current evidence suggests anti-epileptic treatment before the onset of seizures reduces epilepsy severity and risk of cognitive impairment in TSC however identifying these children prior to the onset of seizures is challenging. Our case shows retrospectively reviewed antenatal ultrasounds of a male child diagnosed postnatally at 12 days of life with TSC. Analysis found a soft tissue mass in the right ventricle on antenatal ultrasound which was not captured in the initial ultrasound report. Though there are no reports of sensitivity of neurosonography for the antenatal detection of intracranial abnormalities associated with TSC, our case suggests that antenatal ultrasound could be used as a screening modality for antenatal diagnosis of TSC.

Epilepsy in Children with Tuberous Sclerosis Complex: A Prospective Observational Study in Bangladesh

Background and Purpose

Epilepsy is an important neurologic feature of patients with tuberous sclerosis complex (TSC). Most common seizure types are focal seizure and epileptic spasm. Seizure control often requires multiple antiepileptic drugs. This study has been done to evaluate the seizure types, electro-encephalography (EEG), neuroimaging features, and drug treatment of epilepsy in TSC.

Methods

This prospective observational study has been conducted on epilepsy patients with TSC at Bangabandhu Sheikh Mujib Medical University from 2011 to 2019.

Results

Seventy patients with a mean±standard deviation age of 5.64±3.96 years were identified and 57.1% were female. Most common type of seizure was focal seizure (46%). Epileptic spasm occurred in 17% of patients and all of them had seizure onset before 1 year. In 47% of patients EEG showed focal epileptic discharge; hypsarrhythmia was found in most of the patients with epileptic spasm. Majority of the patients needed more than one drug to control seizure. Only 34% of patients were seizure free for at least 12 months and 22.8% had drug resistant epilepsy.

Conclusions

This study highlights the pattern of seizure, treatment pattern, response to drug, and short-time outcome of children with TSC with epilepsy in a developing country like Bangladesh.

Brain Proteomic Profiling in Intractable Epilepsy Caused by TSC1 Truncating Mutations: A Small Sample Study

Tuberous sclerosis complex (TSC) is a genetic disease characterized by seizures, mental deficiency, and abnormalities of the skin, brain, kidney, heart, and lungs. TSC is inherited in an autosomal dominant manner and is caused by variations in either the TSC1 or TSC2 gene. TSC-related epilepsy (TRE) is the most prevalent and challenging clinical feature of TSC, and more than half of the patients have refractory epilepsy. In clinical practice, we found several patients of intractable epilepsy caused by TSC1 truncating mutations. To study the changes of protein expression in the brain, three cases of diseased brain tissue with TSC1 truncating mutation resected in intractable epilepsy operations and three cases of control brain tissue resected in craniocerebral trauma operations were collected to perform protein spectrum detection, and then the data-independent acquisition (DIA) workflow was used to analyze differentially expressed proteins. As a result, there were 55 up- and 55 down-regulated proteins found in the damaged brain tissue with TSC1 mutation compared to the control. Further bioinformatics analysis revealed that the differentially expressed proteins were mainly concentrated in the synaptic membrane between the patients with TSC and the control. Additionally, TSC1 truncating mutations may affect the pathway of amino acid metabolism. Our study provides a new idea to explore the brain damage mechanism caused by TSC1 mutations.

Congenital lymphedema as a rare and first symptom of tuberous sclerosis complex

Lymphedema are characterized by interstitial edema leading to swelling of extremities. They can be divided into primary and secondary lymphedema. Developmental abnormalities of the lymphatic system are responsible for the primary form of lymphedema. The secondary form of lymphedema is caused by damage of the lymphatic system due to external factors. Lymphedema can rarely be observed in patients with tuberous sclerosis complex (TSC), which is a neurocutaneous syndrome caused by pathogenic variants in the genes TSC1 or TSC2. Patients with TSC usually present with neurological manifestations and the development of multiple benign tumors of ectodermal origin. Typical onset for several symptoms is during the first year of life and in some cases lesions can be detected prenatally. Epilepsy is one of the most common manifestations, affecting up to 90% of TSC patients, and is associated with developmental delay. Early pharmacotherapy improves long term patient outcome. Trio exome sequencing was performed in a 3 weeks old girl with congenital lymphedema of the right lower extremity. Using a filter for de novo variants, the heterozygous missense variant c.2524C>T, p.(Gln842Ter) in TSC1 (NM_000368.4) could be identified. After the first onset of infantile spams at age 7 months treatment with vigabatrin was started immediately. We propose to include TSC1 and TSC2 analysis in the diagnostic work-up of patients with (isolated) congenital lymphedema as early diagnosis facilitates consequent treatment strategies potentially improving the prognosis of TSC patients.

Electro-clinical and neurodevelopmental outcome in six children with early diagnosis of tuberous sclerosis complex and role of the genetic background

Background

Seizures in individuals affected by tuberous sclerosis complex (TSC) commonly develop in the first year of life, are often preceded by a progressive deterioration of the electroencephalogram (EEG), and likely influence developmental outcome. Although early diagnosis of TSC has offered a tremendous opportunity to monitor affected patients before seizure onset, reports of the neurological manifestations of TSC in infants before seizure onset are still scarce. Here we describe early EEG activity, clinical and genetic data and developmental assessment in a group of TSC infants, with the aim of identifying possible prognostic factors for neurodevelopmental outcome.

Methods

We report on six infants diagnosed with TSC pre- or perinatally, who underwent serial Video-EEG recordings during the first two years of life. EEGs were classified based on distribution and intensity of interictal epileptiform discharges, and Vigabatrin was introduced in case of ictal discharges. Psychomotor development, cognitive functioning and behavioral problems were assessed through standardized scales. Molecular testing included analysis for point mutations and deletions/duplications in TSC1 and TSC2.

Results

EEG abnormalities appeared at a mean age of 4 months. Four of the six patients developed seizures. EEG abnormalities preceded the onset of clinical seizures in all of them. The two individuals with good seizure control showed normal development, while the other two exhibited psychomotor delays. The patients who did not develop seizures had normal development. A pathogenic variant in the TSC2 gene was detected in all patients but one. The one without a mutation identified did not develop seizures and showed normal neurodevelopment. Of note, the two patients presenting with the worst outcome (that is, poor seizure control and intellectual/behavioral disability) both carried pathogenic variants in the GAP domain of TSC2.

Conclusion

Our report supports the importance of EEG monitoring before seizure onset in patients with TSC, and the correlation between prompt seizure control and positive neurodevelopmental outcome, regardless of seizure type. Our results also indicate a possible role of the genetic background in influencing the outcome.

Long-term cognitive outcomes in tuberous sclerosis complex

AIM

To investigate the interdependence between risk factors associated with long-term intellectual development in individuals with tuberous sclerosis complex (TSC).

METHOD

The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of individuals with TSC. In phase 1 of the study, baseline measures of intellectual ability, epilepsy, cortical tuber load, and mutation were obtained for 125 children (63 females, 62 males; median age=39mo). In phase 2, at an average of 8 years later, intellectual abilities were estimated for 88 participants with TSC and 35 unaffected siblings. Structural equation modelling was used to determine the risk pathways from genetic mutation through to IQ at phase 2.

RESULTS

Intellectual disability was present in 57% of individuals with TSC. Individuals without intellectual disability had significantly lower mean IQ compared to unaffected siblings, supporting specific genetic factors associated with intellectual impairment. Individuals with TSC who had a slower gain in IQ from infancy to middle childhood were younger at seizure onset and had increased infant seizure severity. Structural equation modelling indicated indirect pathways from genetic mutation, to tuber count, to seizure severity in infancy, through to IQ in middle childhood and adolescence.

INTERPRETATION

Early-onset and severe epilepsy in the first 2 years of life are associated with increased risk of long-term intellectual disability in individuals with TSC, emphasizing the importance of early and effective treatment or prevention of epilepsy.

WHAT THIS PAPER ADDS

Intellectual disability was present in 57% of individuals with tuberous sclerosis complex (TSC). Those with TSC without intellectual disability had significantly lower mean IQ compared to unaffected siblings. Earlier onset and greater severity of seizures in the first 2 years were observed in individuals with a slower gain in intellectual ability. Risk pathways through seizures in the first 2 years predict long-term cognitive outcomes in individuals with TSC.

Update on Drug Management of Refractory Epilepsy in Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is a genetic neurocutaneous disorder with epilepsy as a common and early presenting symptom. The neurological phenotype, however, is variable and unpredictable. Early and refractory seizures, infantile spasms in particular, are associated with a poor neurological outcome. Preliminary data suggests early and aggressive seizure control may mitigate the detrimental neurodevelopmental effects of epilepsy. For infantile spasms, vigabatrin is the first line of treatment, and steroids and classic antiepileptic drugs (AEDs) are suitable for second line. Based on retrospective data, vigabatrin should be considered for other indications, especially in infants with focal seizures, as this may prevent infantile spasms, but also in children and adults with epileptic spasms and tonic seizures. Otherwise, for most seizure types, treatment is similar to that for patients without TSC, including the use of novel AEDs, although limited data are available. Three major developments are changing the field of epilepsy management in TSC. First, final recommendations on preventive treatment with vigabatrin will result from two multicenter trials in the US (PREVeNT, clinicaltrials.gov #NCT02849457) and Europe (EPISTOP, clinicaltrials.gov #NCT02098759). Second, treatment with everolimus, an inhibitor of the mechanistic target of rapamycin (mTOR), reduced seizures when compared to placebo. Further, mTOR inhibitors may have an overall disease-modifying effect. Third, the role of cannabidiol in the treatment of refractory seizures in TSC is yet to be established. With treatment recommendations in TSC, we keep an eye on the prize for the broader field of pediatric epilepsy: the lessons learned from TSC are likely applicable to other epileptic encephalopathies.

Modifying genetic epilepsies - Results from studies on tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous disorder affecting approximately 1 in 6,000 in general population and represents one of the most common genetic causes of epilepsy. Epilepsy affects 90% of the patients and appears in the first 2 years of life in the majority of them. Early onset of epilepsy in the first year of life is associated with high risk of cognitive decline and neuropsychiatric problems including autism. Recently TSC has been recognized as a model of genetic epilepsies. TSC is a genetic condition with known dysregulated mTOR pathway and is increasingly viewed as a model for human epileptogenesis. Moreover, TSC is characterized by a hyperactivation of mTOR (mammalian target of rapamycin) pathway, and mTOR activation was showed to be implicated in epileptogenesis in many animal models and human epilepsies. Recently published studies documented positive effect of preventive or disease modifying treatment of epilepsy in infants with high risk of epilepsy with significantly lower incidence of epilepsy and better cognitive outcome. Further studies on preventive treatment of epilepsy in other genetic epilepsies of early childhood are considered. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Preventive Antiepileptic Treatment in Tuberous Sclerosis Complex: A Long-Term, Prospective Trial

BACKGROUD

Drug-resistant epilepsy is the main risk factor for future intellectual disability in patients with tuberous sclerosis complex. Clinical epileptic seizures are often preceded by electroencephalographic changes, which provide an opportunity for preventive treatment. We evaluated the neuropsychologic and epilepsy outcomes at school age in children with tuberous sclerosis complex who received preventive antiepileptic treatment in infancy.

METHODS

We performed a prospective, nonrandomized clinical trial with 14 infants diagnosed with tuberous sclerosis complex in whom serial electroencephalographic recordings were performed and preventive treatment with vigabatrin initiated when active epileptic discharges were detected. An age-matched control group consisted of 31 infants with tuberous sclerosis complex in whom treatment with vigabatrin was given only after onset of clinical seizures. Results of clinical assessment of epilepsy and cognitive outcomes were analyzed.

RESULTS

All patients in the preventive group (n = 14) and 25 of 31 patients in the standard treatment group were followed through minimum age five years, median 8.8 and 8.0 years in the preventive and standard groups, respectively. The median intelligence quotient was 94 for the preventive group when compared with 46 for the standard group (P < 0.03). Seven of 14 patients (50%) in the preventive group never had a clinical seizure when compared with one of 25 patients (5%) in the standard treatment group (P = 0.001).

CONCLUSIONS

This study provides evidence that preventive antiepileptic treatment in infants with tuberous sclerosis complex improves long-term epilepsy control and cognitive outcome at school age.

Effects of antiepileptic drugs in a new TSC/mTOR-dependent epilepsy mouse model

OBJECTIVE

An epilepsy mouse model for Tuberous Sclerosis Complex (TSC) was developed and validated to investigate the mechanisms underlying epileptogenesis. Furthermore, the possible antiepileptogenic properties of commonly used antiepileptic drugs (AEDs) and new compounds were assessed.

METHODS

Tsc1 deletion was induced in CAMK2A-expressing neurons of adult mice. The antiepileptogenic properties of commonly used AEDs and inhibitors of the mTOR pathways were assessed by EEG recordings and by molecular read outs.

RESULTS

Mice developed epilepsy in a narrow time window (10 ± 2 days) upon Tsc1 gene deletion. Seizure frequency but not duration increased over time. Seizures were lethal within 18 days, were unpredictable, and did not correlate to seizure onset, length or frequency, reminiscent of sudden unexpected death in epilepsy (SUDEP). Tsc1 gene deletion resulted in a strong activation of the mTORC1 pathway, and both epileptogenesis and lethality could be entirely prevented by RHEB1 gene deletion or rapamycin treatment. However, other inhibitors of the mTOR pathway such as AZD8055 and PF4708671 were ineffective. Except for ketogenic diet, none of commonly used AEDs showed an effect on mTORC1 activity. Vigabatrin and ketogenic diet treatment were able to significantly delay seizure onset. In contrast, survival was shortened by lamotrigine.

INTERPRETATION

This novel Tsc1 mouse model is highly suitable to assess the efficacy of antiepileptic and -epileptogenic drugs to treat mTORC1-dependent epilepsy. Additionally, it allows us to study the mechanisms underlying mTORC1-mediated epileptogenesis and SUDEP. We found that early treatment with vigabatrin was not able to prevent epilepsy, but significantly delayed seizure onset.

A randomized controlled trial with everolimus for IQ and autism in tuberous sclerosis complex

OBJECTIVE

To investigate whether mammalian target of rapamycin inhibitor everolimus can improve intellectual disability, autism, and other neuropsychological deficits in children with tuberous sclerosis complex (TSC).

METHODS

In this 12-month, randomized, double-blind, placebo-controlled trial, we attempted to enroll 60 children with TSC and IQ <80, learning disability, special schooling, or autism, aged 4-17 years, without intractable seizures to be assigned to receive everolimus or placebo. Everolimus was titrated to blood trough levels of 5-10 ng/mL. Primary outcome was full-scale IQ; secondary outcomes included autism, neuropsychological functioning, and behavioral problems.

RESULTS

Thirty-two children with TSC were randomized. Intention-to-treat analysis showed no benefit of everolimus on full-scale IQ (treatment effect -5.6 IQ points, 95% confidence interval -12.3 to 1.0). No effect was found on secondary outcomes, including autism and neuropsychological functioning, and questionnaires examining behavioral problems, social functioning, communication skills, executive functioning, sleep, quality of life, and sensory processing. All patients had adverse events. Two patients on everolimus and 2 patients on placebo discontinued treatment due to adverse events.

CONCLUSIONS

Everolimus did not improve cognitive functioning, autism, or neuropsychological deficits in children with TSC. The use of everolimus in children with TSC with the aim of improving cognitive function and behavior should not be encouraged in this age group.

CLINICALTRIALSGOV IDENTIFIER

NCT01730209.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that for children with TSC, everolimus does not improve intellectual disability, autism, behavioral problems, or other neuropsychological deficits.

Early Clinical Predictors of Autism Spectrum Disorder in Infants with Tuberous Sclerosis Complex: Results from the EPISTOP Study

Autism spectrum disorder (ASD) is highly prevalent in subjects with Tuberous Sclerosis Complex (TSC), but we are not still able to reliably predict which infants will develop ASD. This study aimed to identify the early clinical markers of ASD and/or developmental delay (DD) in infants with an early diagnosis of TSC. We prospectively evaluated 82 infants with TSC (6–24 months of age), using a detailed neuropsychological assessment (Bayley Scales of Infant Development—BSID, and Autism Diagnostic Observation Schedule—ADOS), in the context of the EPISTOP (Long-term, prospective study evaluating clinical and molecular biomarkers of EPIleptogenesiS in a genetic model of epilepsy—Tuberous SclerOsis ComPlex) project (NCT02098759). Normal cognitive developmental quotient at 12 months excluded subsequent ASD (negative predictive value 100%). The total score of ADOS at 12 months clearly differentiated children with a future diagnosis of ASD from children without (p = 0.012). Atypical socio-communication behaviors (p < 0.001) were more frequently observed than stereotyped/repetitive behaviors in children with ASD at 24 months. The combined use of BSID and ADOS can reliably identify infants with TSC with a higher risk for ASD at age 6–12 months, allowing for clinicians to target the earliest symptoms of abnormal neurodevelopment with tailored intervention strategies.

Tuberous Sclerosis Complex: Clinical Spectrum and Epilepsy: A Retrospective Chart Review Study

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic neurocutaneous disorder, with heterogeneous manifestations. We aimed to review the clinical presentation of TSC and its association with epilepsy among Saudi population. This was a retrospective chart review study of 88 patients diagnosed with TSC with or without epilepsy. In 38.6% of patients, symptoms began before 1 year of age. The most frequent initial manifestations of TSC were new onset of seizures (68.2%), skin manifestations (46.6%) and development delay (23.9%). During the evolution of the disease 65.9% had epilepsy, 17% facial angiofibromas, 13.6% Shagreen patch, 18.2% heart rhabdomyomas and 12.5% retinal hamartomas. The genetic study for TSC diagnosis was done for 44 patients, 42 (95,4%) of them were genetically confirmed, for whom 13 patients had TSC1 mutation (29.5%), 29 patients were carrying TSC2 gene mutation (65.9%), Genetic test for TSC 1 and TSC 2 were negative for 2 patients (4.5%) despite positive gene mutation in their relative with TSC. The most common manifestations were central nervous system (predominantly epilepsy) and dermatological manifestations. Most of the patients develop epilepsy with multiple seizure types. TSC 2 mutation is more common than TSC 1 mutation.

The use of rapamycin in patients with tuberous sclerosis complex: Long-term results

PURPOSE

The purpose of this study was to evaluate the long-term results of eight cases diagnosed with tuberous sclerosis complex (TSC) and receiving rapamycin therapy because of epileptic seizures and/or accompanying TSC findings.

METHOD

Rapamycin therapy was initiated at a dose of 1.5 mg/m². Seizure frequency, electroencephalographic (EEG) findings, renal and cranial imaging findings, and cutaneous lesions over 3- to 6-month periods during follow-up and treatment were evaluated.

RESULTS

Four girls and four boys aged 4-16 years at the start of rapamycin therapy and now aged 9-24 years were evaluated. Duration of rapamycin therapy was 1-5 years, and the monitoring period after commencement of rapamycin therapy lasted 5-8 years. Positive effects were observed at 9-12 months in three out of six cases of renal angiomyolipoma (AML) and in the second year of treatment in one. An increase in AML dimensions was observed in three cases after treatment was stopped. Seizure control was established in the first year of rapamycin therapy in all cases. An increased frequency of seizures was observed in three cases after the second year of treatment. No seizure recurrence was determined in the second year of treatment with rapamycin in five out of eight cases. Recurrence of seizure was observed in 6-12 months after the discontinuation of rapamycin in three cases.

CONCLUSION

Rapamycin therapy exhibits positive effects on epileptic seizures in cases of TSC in 1-2 years but these positive effects on seizure control of rapamycin therapy decline after the second year. Larger case series are still needed to determine the duration and effectiveness of treatment in childhood.