The role of mTOR inhibitors in preventing epileptogenesis in patients with TSC: Current evidence and future perspectives

Treatment options for post-traumatic epilepsy: an update on clinical and translational aspects

INTRODUCTION

Post-traumatic epilepsy (PTE) accounts for 10% to 20% of all symptomatic epilepsies and 5% of all forms of epilepsy, and drug resistance is reported in up to 45% of cases.

AREAS COVERED

This is a focused narrative review that discusses the available data on the current and new PTE treatments, giving particular attention to the last 10 years.

EXPERT OPINION

Despite the disappointing results of many antiseizure medications (ASMs) in preventing epileptogenicity, it is still unclear whether the early intervention could lead to different clinical phenotypes in terms, for example, of seizure severity, drug resistance and comorbidity patterns. The same applies to compounds targeting neuroinflammation, oxidative stress and neurotransmission modulation. The heterogeneity of etiologies leading to PTE has limited the investigation and implementation of specific interventions. New studies must focus on identifying common pathways and mechanisms shared by different etiological processes, identifying biomarkers, and validating animal models of epileptogenesis concerning PTE. Drug repurposing research will facilitate rapid translation into clinical research. Multitarget drug combinations will also receive increasing attention. In terms of non-pharmacological treatments, Vagus Nerve Stimulation seems to be a good option, while epilepsy surgery and Deep Brain Stimulation deserve further attention.

Investigation of epilepsy-related genes in a Drosophila model

ABSTRACT

Complex genetic architecture is the major cause of heterogeneity in epilepsy, which poses challenges for accurate diagnosis and precise treatment. A large number of epilepsy candidate genes have been identified from clinical studies, particularly with the widespread use of next-generation sequencing. Validating these candidate genes is emerging as a valuable yet challenging task. Drosophila serves as an ideal animal model for validating candidate genes associated with neurogenetic disorders such as epilepsy, due to its rapid reproduction rate, powerful genetic tools, and efficient use of ethological and electrophysiological assays. Here, we systematically summarize the advantageous techniques of the Drosophila model used to investigate epilepsy genes, including genetic tools for manipulating target gene expression, ethological assays for seizure-like behaviors, electrophysiological techniques, and functional imaging for recording neural activity. We then introduce several typical strategies for identifying epilepsy genes and provide new insights into gene-gene interactions in epilepsy with polygenic causes. We summarize well- established precision medicine strategies for epilepsy and discuss prospective treatment options, including drug therapy and gene therapy for genetic epilepsy based on the Drosophila model. Finally, we also address genetic counseling and assisted reproductive technology as potential approaches for the prevention of genetic epilepsy.

Early development and epilepsy in tuberous sclerosis complex: A prospective longitudinal study

AIM

To characterize early changes in developmental ability, language, and adaptive behaviour in infants diagnosed with tuberous sclerosis complex (TSC), and determine whether clinical features of epilepsy influence this pathway.

METHOD

Prospective, longitudinal data were collected within the Early Development in Tuberous Sclerosis (EDiTS) Study to track development of infants with TSC (n = 32) and typically developing infants (n = 33) between 3 and 24 months of age. Questionnaire and observational measures were used at up to seven timepoints to assess infants' adaptive behaviour, developmental ability, language, and epilepsy.

RESULTS

A significant group by age interaction effect showed that infants with TSC had lower adaptive functioning at 18 to 24 months old (intercept = 88.12, slope estimate = -0.82, p < 0.001) and lower developmental ability scores from 10 months old (intercept = 83.33, slope estimate = -1.44, p < 0.001) compared to typically developing infants. Early epilepsy severity was a significant predictor of these emerging developmental (R2 = 0.35, p = 0.004, 95% confidence interval [CI] -0.08 to -0.01) and adaptive behaviour delays (R2 = 0.34, p = 0.004, 95% CI -0.05 to -0.01]). Lower vocabulary production (intercept = -1.25, slope = -0.12, p < 0.001) and comprehension scores (intercept = 2.39, slope estimate = -0.05, p < 0.001) in infants with TSC at 24 months old were not associated with epilepsy severity.

INTERPRETATION

Divergence of developmental ability and adaptive functioning skills occur in infants with TSC from 10 and 18 months, respectively. Associations between early epilepsy severity and impaired development supports the importance of early intervention to reduce seizure severity.

Further advances in epilepsy

In 2017, one of us reviewed advances in epilepsy (Manford in J Neurol 264:1811-1824, 2017). The current paper brings that review up to date and gives a slight change in emphasis. Once again, the story is of evolution rather than revolution. In recognition that most of our current medications act on neurotransmitters or ion channels, and not on the underlying changes in connectivity and pathways, they have been renamed as antiseizure (ASM) medications rather than antiepileptic drugs. Cenobamate is the one newly licensed medication for broader use in focal epilepsy but there have been a number of developments for specific disorders. We review new players and look forward to new developments in the light of evolving underlying science. We look at teratogenicity; old villains and new concerns in which clinicians play a vital role in explaining and balancing the risks. Medical treatment of status epilepticus, long without evidence, has benefitted from high-quality trials to inform practice; like buses, several arriving at once. Surgical treatment continues to be refined with improvements in the pre-surgical evaluation of patients, especially with new imaging techniques. Alternatives including stereotactic radiotherapy have received further focus and targets for palliative stimulation techniques have grown in number. Individuals' autonomy and quality of life continue to be the subject of research with refinement of what clinicians can do to help persons with epilepsy (PWE) achieve control. This includes seizure management but extends to broader considerations of human empowerment, needs and desires, which may be aided by emerging technologies such as seizure detection devices. The role of specialist nurses in improving that quality has been reinforced by specific endorsement from the International League against Epilepsy (ILAE).

The complexities underlying epilepsy in people with glioblastoma

Seizures are among the most common clinical signs in people with glioblastoma. Advances over the past 5 years, including new clinical trial data, have increased the understanding of why some individuals with glioblastoma are susceptible to seizures, how seizures manifest clinically, and what implications seizures have for patient management. The pathophysiology of epilepsy in people with glioblastoma relates to a combination of intrinsic epileptogenicity of tumour tissue, alterations in the tumour and peritumoural microenvironment, and the physical and functional disturbance of adjacent brain structures. Successful management of epilepsy in people with glioblastoma remains challenging; factors such as drug-drug interactions between cancer therapies and antiseizure medications, and medication side-effects, can affect seizure outcomes and quality of life. Advances in novel therapies provide some promise for people with glioblastoma; however, the effects of these therapies on seizures are yet to be fully determined. Looking forward, insights into electrical activity as a driver of tumour cell growth and the intrinsic hyperexcitability of tumour tissue might represent useful targets for treatment and disease modification. There is a pressing need for large randomised clinical trials in this field.

Bi-allelic TTI1 variants cause an autosomal-recessive neurodevelopmental disorder with microcephaly

Telomere maintenance 2 (TELO2), Tel2 interacting protein 2 (TTI2), and Tel2 interacting protein 1 (TTI1) are the three components of the conserved Triple T (TTT) complex that modulates activity of phosphatidylinositol 3-kinase-related protein kinases (PIKKs), including mTOR, ATM, and ATR, by regulating the assembly of mTOR complex 1 (mTORC1). The TTT complex is essential for the expression, maturation, and stability of ATM and ATR in response to DNA damage. TELO2- and TTI2-related bi-allelic autosomal-recessive (AR) encephalopathies have been described in individuals with moderate to severe intellectual disability (ID), short stature, postnatal microcephaly, and a movement disorder (in the case of variants within TELO2). We present clinical, genomic, and functional data from 11 individuals in 9 unrelated families with bi-allelic variants in TTI1. All present with ID, and most with microcephaly, short stature, and a movement disorder. Functional studies performed in HEK293T cell lines and fibroblasts and lymphoblastoid cells derived from 4 unrelated individuals showed impairment of the TTT complex and of mTOR pathway activity which is improved by treatment with Rapamycin. Our data delineate a TTI1-related neurodevelopmental disorder and expand the group of disorders related to the TTT complex.

Integration of transcriptomic and metabolomic profiling of encystation in Cryptocaryon irritans regulated by rapamycin

Encystation in Cryptocaryon irritans is a fundamental process for environmental resistance and development. Autophagy participates in the encystation of ciliates, and rapamycin can induce autophagy in the cells. A set of genes and metabolites related to autophagy and encystation are highly elaborative. The existence of these genes and metabolites and their role are well characterized. However, little is known about their role in protozoans such as ciliates. The newly produced C. irritans protomonts were exposed to an optimal concentration of rapamycin (1400 nM), and the survival, encystation, microstructure/ultrastructure, transcriptomic and metabolomic profile in treated and control protomonts were investigated. The results showed that exposure of protomonts to rapamycin at 4 h significantly lowered the survival and encystation rates to 91.62 % and 98.44 % compared to the control group (100 %, p ≤ 0.05). Morphological alterations observed in light microscopy and transmission electron microscopy (TEM) demonstrated that the drug significantly changed cell symmetry by causing the formation of various autophagic vacuoles/vesicles. The transcriptome sequencing of rapamycin-treated protomont revealed that 2249 (1837 up-regulated and 977 down-regulated) differentially expressed genes (DEGs) were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that 226 DEGs were successfully annotated in 21 pathways (p˂0.05), including most enriched pathways apoptosis and phagosome with 25 and 24 DEGs, respectively. Most unigenes were assigned to autophagy-related pathways; 24 DEGs were classified into phagosomes, and 15 DEGs were assigned to lysosome pathways. Cytoskeleton and cell progression-associated genes were down-regulated. Besides, cell death-inducing proteins were up-regulated. The metabolomic analysis revealed exposure to rapamycin treatment enhanced protomont metabolites, including L-Cysteine, which is related to autophagy. Rapamycin had influenced the gene and metabolites of protomont; activating autophagy with inhibition of mechanistic target of rapamycin, (mTOR). The process negatively influences protomont morphology, encystation, and survival. Further autophagy-related gene silencing can be investigated via genome sequencing of C. irritans to study encystation.

Tuberous Sclerosis Complex 1 Deficiency in Macrophages Promotes Unclassical Inflammatory Response to Lipopolysaccharide In Vitro and Dextran Sodium Sulfate-Induced Colitis in Mice

Human tuberous sclerosis (TSC) is mainly caused by genetic mutations of tuberous TSC1or TSC2. Recent studies found that TSC1 deficiency promoted classical M1 macrophage polarization. However, whether TSC1 regulates other inflammatory cytokine expression in lipopolysaccharidem (LPS)-stimulated macrophages is unknown. Herein, we studied the cytokine expression profile of wild-type (WT) and TSC1-deleted macrophages after LPS stimulation in vitro and the pathogenesis of dextran sodium sulfate (DSS)-induced colitis in mice with myeloid-specific TSC1 deletion (TSC1cKO mice). We found that TSC1-deficient macrophages exhibited the enhanced secretion of interleukin-17A (IL-17A), IL-17F, and interferon-gamma (IFN-γ) in response to LPS stimulation in vitro. This is in contrast to LPS-stimulated WT macrophages, which usually do not. Importantly, TSC1cKO mice exhibited exacerbated DSS-induced acute colitis with severer symptoms. MTOR deletion or rapamycin treatment significantly reversed the enhanced expressions of IL-17A, IL-17F, and IFN-γ in LPS-stimulated TSC1-deficient macrophages in vitro and rescued the enhanced DSS-induced colitis in TSC1cKO mice, indicating that TSC1 deficiency increased these cytokine productions in an mTOR-dependent manner. RNA-sequencing and molecular studies indicated that TSC1 deficiency enhanced the aerobic glycolysis process and the activities of mTOR-STAT3-RORγT pathway in LPS-stimulated macrophages. Inhibition of aerobic glycolysis, STAT3, or RORγT reversed IL-17 and IFN-γ expression in LPS-treated TSC1-deficient macrophages. Thus, TSC1 is essential for macrophages to shut down IL-17A, IL-17F, and IFN-γ expression during LPS stimulation by suppressing the aerobic glycolysis process and mTOR-STAT3, RORγT, and T-bet pathways. The present study uncovered the key role of TSC1 in shutting down IL-17A, IL-17F, and IFN-γ expressions in LPS-treated macrophages.

A molecular framework for autistic experiences: Mitochondrial allostatic load as a mediator between autism and psychopathology

Molecular autism research is evolving toward a biopsychosocial framework that is more informed by autistic experiences. In this context, research aims are moving away from correcting external autistic behaviors and toward alleviating internal distress. Autism Spectrum Conditions (ASCs) are associated with high rates of depression, suicidality and other comorbid psychopathologies, but this relationship is poorly understood. Here, we integrate emerging characterizations of internal autistic experiences within a molecular framework to yield insight into the prevalence of psychopathology in ASC. We demonstrate that descriptions of social camouflaging and autistic burnout resonate closely with the accepted definitions for early life stress (ELS) and chronic adolescent stress (CAS). We propose that social camouflaging could be considered a distinct form of CAS that contributes to allostatic overload, culminating in a pathophysiological state that is experienced as autistic burnout. Autistic burnout is thought to contribute to psychopathology via psychological and physiological mechanisms, but these remain largely unexplored by molecular researchers. Building on converging fields in molecular neuroscience, we discuss the substantial evidence implicating mitochondrial dysfunction in ASC to propose a novel role for mitochondrial allostatic load in the relationship between autism and psychopathology. An interplay between mitochondrial, neuroimmune and neuroendocrine signaling is increasingly implicated in stress-related psychopathologies, and these molecular players are also associated with neurodevelopmental, neurophysiological and neurochemical aspects of ASC. Together, this suggests an increased exposure and underlying molecular susceptibility to ELS that increases the risk of psychopathology in ASC. This article describes an integrative framework shaped by autistic experiences that highlights novel avenues for molecular research into mechanisms that directly affect the quality of life and wellbeing of autistic individuals. Moreover, this framework emphasizes the need for increased access to diagnoses, accommodations, and resources to improve mental health outcomes in autism.

Genome sequencing of 320 Chinese children with epilepsy: a clinical and molecular study

The aim of this study is to evaluate the diagnostic value of genome sequencing in children with epilepsy, and to provide genome sequencing-based insights into the molecular genetic mechanisms of epilepsy to help establish accurate diagnoses, design appropriate treatments and assist in genetic counselling. We performed genome sequencing on 320 Chinese children with epilepsy, and interpreted single-nucleotide variants and copy number variants of all samples. The complete pedigree and clinical data of the probands were established and followed up. The clinical phenotypes, treatments, prognoses and genotypes of the patients were analysed. Age at seizure onset ranged from 1 day to 17 years, with a median of 4.3 years. Pathogenic/likely pathogenic variants were found in 117 of the 320 children (36.6%), of whom 93 (29.1%) had single-nucleotide variants, 22 (6.9%) had copy number variants and two had both single-nucleotide variants and copy number variants. Single-nucleotide variants were most frequently found in SCN1A (10/95, 10.5%), which is associated with Dravet syndrome, followed by PRRT2 (8/95, 8.4%), which is associated with benign familial infantile epilepsy, and TSC2 (7/95, 7.4%), which is associated with tuberous sclerosis. Among the copy number variants, there were three with a length <25 kilobases. The most common recurrent copy number variants were 17p13.3 deletions (5/24, 20.8%), 16p11.2 deletions (4/24, 16.7%), and 7q11.23 duplications (2/24, 8.3%), which are associated with epilepsy, developmental retardation and congenital abnormalities. Four particular 16p11.2 deletions and two 15q11.2 deletions were considered to be susceptibility factors contributing to neurodevelopmental disorders associated with epilepsy. The diagnostic yield was 75.0% in patients with seizure onset during the first postnatal month, and gradually decreased in patients with seizure onset at a later age. Forty-two patients (13.1%) were found to be specifically treatable for the underlying genetic cause identified by genome sequencing. Three of them received corresponding targeted therapies and demonstrated favourable prognoses. Genome sequencing provides complete genetic diagnosis, thus enabling individualized treatment and genetic counselling for the parents of the patients. Genome sequencing is expected to become the first choice of methods for genetic testing of patients with epilepsy.

Application of Thermodynamics and Protein–Protein Interaction Network Topology for Discovery of Potential New Treatments for Temporal Lobe Epilepsy

In this paper, we propose a bioinformatics-based method, which introduces thermodynamic measures and topological characteristics aimed to identify potential drug targets for pharmaco-resistant epileptic patients. We apply the Gibbs homology analysis to the protein–protein interaction network characteristic of temporal lobe epilepsy. With the identification of key proteins involved in the disease, particularly a number of ribosomal proteins, an assessment of their inhibitors is the next logical step. The results of our work offer a direction for future development of prospective therapeutic solutions for epilepsy patients, especially those who are not responding to the current standard of care.

Review of the treatment options for epilepsy in tuberous sclerosis complex: towards precision medicine

Tuberous sclerosis complex (TSC) is a rare genetic disorder caused by mutations in the TSC1 or TSC2 genes, which encode proteins that antagonise the mammalian isoform of the target of rapamycin complex 1 (mTORC1) - a key mediator of cell growth and metabolism. TSC is characterised by the development of benign tumours in multiple organs, together with neurological manifestations including epilepsy and TSC-associated neuropsychiatric disorders (TAND). Epilepsy occurs frequently and is associated with significant morbidity and mortality; however, the management is challenging due to the intractable nature of the seizures. Preventative epilepsy treatment is a key aim, especially as patients with epilepsy may be at a higher risk of developing severe cognitive and behavioural impairment. Vigabatrin given preventatively reduces the risk and severity of epilepsy although the benefits for TAND are inconclusive. These promising results could pave the way for evaluating other treatments in a preventative capacity, especially those that may address the underlying pathophysiology of TSC, including everolimus, cannabidiol and the ketogenic diet (KD). Everolimus is an mTOR inhibitor approved for the adjunctive treatment of refractory TSC-associated seizures that has demonstrated significant reductions in seizure frequency compared with placebo, improvements that were sustained after 2 years of treatment. Highly purified cannabidiol, recently approved in the US as Epidiolex® for TSC-associated seizures in patients ⩾1 years of age, and the KD, may also participate in the regulation of the mTOR pathway. This review focusses on the pivotal clinical evidence surrounding these potential targeted therapies that may form the foundation of precision medicine for TSC-associated epilepsy, as well as other current treatments including anti-seizure drugs, vagus nerve stimulation and surgery. New future therapies are also discussed, together with the potential for preventative treatment with targeted therapies. Due to advances in understanding the molecular genetics and pathophysiology, TSC represents a prototypic clinical syndrome for studying epileptogenesis and the impact of precision medicine.

SARS-CoV-2 Neuronal Invasion and Complications: Potential Mechanisms and Therapeutic Approaches

Clinical reports suggest that the coronavirus disease-19 (COVID-19) pandemic caused by severe acute respiratory syndrome (SARS)-coronavirus-2 (CoV-2) has not only taken millions of lives, but has also created a major crisis of neurologic complications that persist even after recovery from the disease. Autopsies of patients confirm the presence of the coronaviruses in the CNS, especially in the brain. The invasion and transmission of SARS-CoV-2 in the CNS is not clearly defined, but, because the endocytic pathway has become an important target for the development of therapeutic strategies for COVID-19, it is necessary to understand endocytic processes in the CNS. In addition, mitochondria and mechanistic target of rapamycin (mTOR) signaling pathways play a critical role in the antiviral immune response, and may also be critical for endocytic activity. Furthermore, dysfunctions of mitochondria and mTOR signaling pathways have been associated with some high-risk conditions such as diabetes and immunodeficiency for developing severe complications observed in COVID-19 patients. However, the role of these pathways in SARS-CoV-2 infection and spread are largely unknown. In this review, we discuss the potential mechanisms of SARS-CoV-2 entry into the CNS and how mitochondria and mTOR pathways might regulate endocytic vesicle-mitochondria interactions and dynamics during SARS-CoV-2 infection. The mechanisms that plausibly account for severe neurologic complications with COVID-19 and potential treatments with Food and Drug Administration-approved drugs targeting mitochondria and the mTOR pathways are also addressed.

Direct and indirect costs and cost-driving factors of Tuberous sclerosis complex in children, adolescents, and caregivers: a multicenter cohort study

BACKGROUND

Tuberous sclerosis complex (TSC), a multisystem genetic disorder, affects many organs and systems, characterized by benign growths. This German multicenter study estimated the disease-specific costs and cost-driving factors associated with various organ manifestations in TSC patients.

METHODS

A validated, three-month, retrospective questionnaire was administered to assess the sociodemographic and clinical characteristics, organ manifestations, direct, indirect, out-of-pocket, and nursing care-level costs, completed by caregivers of patients with TSC throughout Germany.

RESULTS

The caregivers of 184 patients (mean age 9.8 ± 5.3 years, range 0.7-21.8 years) submitted questionnaires. The reported TSC disease manifestations included epilepsy (92%), skin disorders (86%), structural brain disorders (83%), heart and circulatory system disorders (67%), kidney and urinary tract disorders (53%), and psychiatric disorders (51%). Genetic variations in TSC2 were reported in 46% of patients, whereas 14% were reported in TSC1. Mean total direct health care costs were EUR 4949 [95% confidence interval (95% CI) EUR 4088-5863, median EUR 2062] per patient over three months. Medication costs represented the largest direct cost category (54% of total direct costs, mean EUR 2658), with mechanistic target of rapamycin (mTOR) inhibitors representing the largest share (47%, EUR 2309). The cost of anti-seizure drugs (ASDs) accounted for a mean of only EUR 260 (5%). Inpatient costs (21%, EUR 1027) and ancillary therapy costs (8%, EUR 407) were also important direct cost components. The mean nursing care-level costs were EUR 1163 (95% CI EUR 1027-1314, median EUR 1635) over three months. Total indirect costs totaled a mean of EUR 2813 (95% CI EUR 2221-3394, median EUR 215) for mothers and EUR 372 (95% CI EUR 193-586, median EUR 0) for fathers. Multiple regression analyses revealed polytherapy with two or more ASDs and the use of mTOR inhibitors as independent cost-driving factors of total direct costs. Disability and psychiatric disease were independent cost-driving factors for total indirect costs as well as for nursing care-level costs.

CONCLUSIONS

This study revealed substantial direct (including medication), nursing care-level, and indirect costs associated with TSC over three months, highlighting the spectrum of organ manifestations and their treatment needs in the German healthcare setting.

TRIAL REGISTRATION

DRKS, DRKS00016045. Registered 01 March 2019, http://www.drks.de/DRKS00016045.

Direct and indirect costs and cost-driving factors in adults with tuberous sclerosis complex: a multicenter cohort study and a review of the literature

Background

Tuberous sclerosis complex (TSC) is a monogenetic, multisystem disorder characterized by benign growths due to TSC1 or TSC2 mutations. This German multicenter study estimated the costs and related cost drivers associated with organ manifestations in adults with TSC.

Methods

A validated, three-month, retrospective questionnaire assessed the sociodemographic and clinical characteristics, organ manifestations, direct, indirect, out-of-pocket (OOP), and nursing care-level costs among adult individuals with TSC throughout Germany from a societal perspective (costing year: 2019).

Results

We enrolled 192 adults with TSC (mean age: 33.4 ± 12.7 years; range: 18–78 years, 51.6% [n = 99] women). Reported TSC disease manifestations included skin (94.8%) and kidney and urinary tract (74%) disorders, epilepsy (72.9%), structural brain defects (67.2%), psychiatric disorders (50.5%), heart and circulatory system disorders (50.5%), and lymphangioleiomyomatosis (11.5%). TSC1 and TSC2 mutations were reported in 16.7% and 25% of respondents, respectively. Mean direct health care costs totaled EUR 6452 (median EUR 1920; 95% confidence interval [CI] EUR 5533–7422) per patient over three months. Medication costs represented the major direct cost category (77% of total direct costs; mean EUR 4953), and mechanistic target of rapamycin (mTOR) inhibitors represented the largest share (68%, EUR 4358). Mean antiseizure drug (ASD) costs were only EUR 415 (6%). Inpatient costs (8%, EUR 518) and outpatient treatment costs (7%; EUR 467) were important further direct cost components. The mean care grade allowance as an approximator of informal nursing care costs was EUR 929 (median EUR 0; 95% CI EUR 780–1083) over three months. Mean indirect costs totaled EUR 3174 (median EUR 0; 95% CI EUR 2503–3840) among working-age individuals (< 67 years in Germany). Multiple regression analyses revealed mTOR inhibitor use and persistent seizures as independent cost-driving factors for total direct costs. Older age and disability were independent cost-driving factors for total indirect costs, whereas epilepsy, psychiatric disease, and disability were independent cost-driving factors for nursing care costs.

Conclusions

This three-month study revealed substantial direct healthcare, indirect healthcare, and medication costs associated with TSC in Germany. This study highlights the spectrum of organ manifestations and their associated treatment needs in the German healthcare setting. Trial registration: DRKS, DRKS00016045. Registered 01 March 2019, http://www.drks.de/DRKS00016045.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01838-w.

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.

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.

A novel possible familial cause of epilepsy of infancy with migrating focal seizures related to SZT2 gene variant

Seizure threshold-2 (SZT2) gene variants have been associated with a decrease in seizure threshold resulting in variable phenotypic expressions ranging from mild-moderate intellectual disabilities without seizures, to an early-onset epileptic encephalopathy with severe cognitive impairment. In addition, hypotonia and distinctive facial dysmorphism, including a high forehead and to a lesser extent ptosis and down-slanting palpebral fissures, were present in the majority. We herein report a novel SZT2 variant in one of two siblings both diagnosed with epilepsy of infancy with migrating focal seizures (EIMFS). This report is the fourth to document a possible familial case in EIMFS, a condition that was not previously associated with SZT2 variant. This report expands the phenotypic expression of SZT2, corroborates the importance of genetic counseling in some cases of EIMFS, and highlights the efficacy of potassium bromide in controlling the seizures associated with this condition.

Tuberous Sclerosis Complex: Early Screening and Infant Outcome in NICU

OBJECTIVE

We describe the clinical and genetic features, drug use and neuropsychiatric disorders of infants diagnosed with tuberous sclerosis complex (TSC) within 3 months of age at a neonatal intensive care unit (NICU) to better understand the different outcomes from early screening.

METHODS

In this retrospective study, we consisted of 42 infants with a definitive TSC diagnosis by genetic criteria (TSC1 = 8, TSC2 = 34). The different phenotypes and outcomes between patients with TSC1 and TSC2 mutations were analyzed.

RESULTS

The most common initial presenting features of TSC were cortical tubers on magnetic resonance imaging (50%), hypomelanotic macules on skin (47.61%) and spasm (42.85%), when they were diagnosed. Following disease progression to time of follow-up 1 year later, we found that the rate of epilepsy increased from 42.85% to 75.61% and that of cardiac rhabdomyoma increased from 28.57% to 43.9%. The median age at first presentation was 7.84 ± 1.88 months. We also found that 54.83% of patients on medication were seizure free for over 1 year, and that 43.9% of patients have intellectual disability. In total, 42 variants of TSC were detected, including 12 novel variants. We found no evidence of an association between different clinical features and their outcomes among patients with different gene mutations.

CONCLUSION

Early diagnosis of TSC in NICU opens a window of opportunity for early, more effective treatment of epilepsy as well as reduces the risk of neurological conditions.

Everolimus als krankheitsspezifische Therapieoption bei mit tuberöser Sklerose assoziierter, therapierefraktärer Epilepsie – ein systematischer Überblick

Tuberöse Sklerose („tuberous sclerosis complex“ [TSC]) ist eine seltene genetische Erkrankung, die neben kutanen und viszeralen Organmanifestationen typischerweise bereits in einem sehr frühen Erkrankungsstadium mit einer schweren, meist therapierefraktären Epilepsie einhergeht. Aufgrund seiner direkten Wirkung am durch TSC dysregulierten mTOR-Signalweg sowie der synergistischen Effekte auf andere Organmanifestationen kommt das Rapamycin-Derivat Everolimus (EVE) zunehmend zur Anwendung. Ziel dieses systematischen Reviews ist, die Wirksamkeit, Sicherheit und Verträglichkeit von EVE bei Patienten mit TSC-assoziierter, therapierefraktärer Epilepsie aufzuarbeiten.

Efficacy, Retention and Tolerability of Everolimus in Patients with Tuberous Sclerosis Complex: A Survey-Based Study on Patients' Perspectives

BACKGROUND

The approval of everolimus (EVE) for the treatment of angiomyolipoma (2013), subependymal giant cell astrocytoma (2013) and drug-refractory epilepsy (2017) in patients with tuberous sclerosis complex (TSC) represents the first disease-modifying treatment option available for this rare and complex genetic disorder.

OBJECTIVE

The objective of this study was to analyse the use, efficacy, tolerability and treatment retention of EVE in patients with TSC in Germany from the patient's perspective.

METHODS

A structured cross-age survey was conducted at 26 specialised TSC centres in Germany and by the German TSC patient advocacy group between February and July 2019, enrolling children, adolescents and adult patients with TSC.

RESULTS

Of 365 participants, 36.7% (n = 134) reported the current or past intake of EVE, including 31.5% (n = 115) who were taking EVE at study entry. The mean EVE dosage was 6.1 ± 2.9 mg/m² (median: 5.6 mg/m², range 2.0-15.1 mg/m²) in children and adolescents and 4 ± 2.1 mg/m² (median: 3.7 mg/m², range 0.8-10.1 mg/m²) in adult patients. An early diagnosis of TSC, the presence of angiomyolipoma, drug-refractory epilepsy, neuropsychiatric manifestations, subependymal giant cell astrocytoma, cardiac rhabdomyoma and overall multi-organ involvement were associated with the use of EVE as a disease-modifying treatment. The reported efficacy was 64.0% for angiomyolipoma (75% in adult patients), 66.2% for drug-refractory epilepsy, and 54.4% for subependymal giant cell astrocytoma. The overall retention rate for EVE was 85.8%. The retention rates after 12 months of EVE therapy were higher among adults (93.7%) than among children and adolescents (88.7%; 90.5% vs 77.4% after 24 months; 87.3% vs 77.4% after 36 months). Tolerability was acceptable, with 70.9% of patients overall reporting adverse events, including stomatitis (47.0%), acne-like rash (7.7%), increased susceptibility to common infections and lymphoedema (each 6.0%), which were the most frequently reported symptoms. With a total score of 41.7 compared with 36.8 among patients not taking EVE, patients currently being treated with EVE showed an increased Liverpool Adverse Event Profile. Noticeable deviations in the sub-items 'tiredness', 'skin problems' and 'mouth/gum problems', which are likely related to EVE-typical adverse effects, were more frequently reported among patients taking EVE.

CONCLUSIONS

From the patients' perspective, EVE is an effective and relatively well-tolerated disease-modifying treatment option for children, adolescents and adults with TSC, associated with a high long-term retention rate that can be individually considered for each patient. Everolimus therapy should ideally be supervised by a centre experienced in the use of mechanistic target of rapamycin inhibitors, and adverse effects should be monitored on a regular basis.

Genetics of tuberous sclerosis complex: an update

PURPOSE

To review the current genetic aspects of tuberous sclerosis complex.

METHODS

Review of the literature.

RESULTS

Tuberous sclerosis complex (TSC), a long known childhood-onset monogenic disorder, characterized by hamartoma formation affecting mainly the brain, heart, kidney, lung, and skin, is associated with a high morbidity burden and risk of a reduced life span. The identification of TSC1 and TSC2, as tumor suppressor genes causative of the disorder, led to the elucidation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway and its pivotal role in the pathogenesis of hamartoma formation. This knowledge was translated into standard clinical practice with the discovery of rapamycin, and additional analogues, as inhibitors of mTORC1.

CONCLUSION

Next-generation sequencing was proven to be fundamental to drive research of tumorigenesis in TSC, hopefully leading to new therapeutic options in the future.

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.

An update on the central nervous system manifestations of tuberous sclerosis complex

The autosomal dominant disorder tuberous sclerosis complex (TSC) is characterized by an array of manifestations both within and outside of the central nervous system (CNS), including hamartomas and other malformations. TSC is caused by mutations in the TSC1 or TSC2 gene resulting in activation of the mechanistic target of rapamycin (mTOR) signaling pathway. Study of TSC has shed light on the critical role of the mTOR pathway in neurodevelopment. This update reviews the genetic basis of TSC, its cardinal phenotypic CNS features, and recent developments in the field of TSC and other mTOR-altered disorders.

Advances in genetic testing and optimization of clinical management in children and adults with epilepsy

Introduction: Epileptic disorders are a heterogeneous group of medical conditions with epilepsy as the common denominator. Genetic causes, electro-clinical features, and management significantly vary according to the specific condition.Areas covered: Relevant diagnostic advances have been achieved thanks to the advent of Next Generation Sequencing (NGS)-based molecular techniques. These revolutionary tools allow to sequence all coding (whole exome sequencing, WES) and non-coding (whole genome sequencing, WGS) regions of human genome, with a potentially huge impact on patient care and scientific research.Expert opinion: The application of these tests in children and adults with epilepsy has led to the identification of new causative genes, widening the knowledge on the pathophysiology of epilepsy and resulting in therapeutic implications. This review will explore the most recent advancements in genetic testing and provide up-to-date approaches for the choice of the correct test in patients with epilepsy.

A systematic review on the burden of illness in individuals with tuberous sclerosis complex (TSC)

OBJECTIVE

This review will summarize current knowledge on the burden of illness (BOI) in tuberous sclerosis complex (TSC), a multisystem genetic disorder manifesting with hamartomas throughout the body, including mainly the kidneys, brain, skin, eyes, heart, and lungs.

METHODS

We performed a systematic analysis of the available literature on BOI in TSC according to the PRISMA guidelines. All studies irrespective of participant age that reported on individual and societal measures of disease burden (e.g. health care resource use, costs, quality of life) were included.

RESULTS

We identified 33 studies reporting BOI in TSC patients. Most studies (21) reported health care resource use, while 14 studies reported quality of life and 10 studies mentioned costs associated with TSC. Only eight research papers reported caregiver BOI. Substantial BOI occurs from most manifestations of the disorder, particularly from pharmacoresistant epilepsy, neuropsychiatric, renal and skin manifestations. While less frequent, pulmonary complications also lead to a high individual BOI. The range for the mean annual direct costs varied widely between 424 and 98,008 International Dollar purchasing power parities (PPP-$). Brain surgery, end-stage renal disease with dialysis, and pulmonary complications all incur particularly high costs. There is a dearth of information regarding indirect costs in TSC. Mortality overall is increased compared to general population; and most TSC related deaths occur as a result of complications from seizures as well as renal complications. Long term studies report mortality between 4.8 and 8.3% for a follow-up of 8 to 17.4 years.

CONCLUSIONS

TSC patients and their caregivers have a high burden of illness, and TSC patients incur high costs in health care systems. At the same time, the provision of inadequate treatment that does not adhere to published guidelines is common and centralized TSC care is received by no more than half of individuals who need it, especially adults. Further studies focusing on the cost effectiveness and BOI outcomes of coordinated TSC care as well as of new treatment options such as mTOR inhibitors are necessary.

Non-convulsive status epilepticus in two patients with tuberous sclerosis

Tuberous sclerosis (TSC) is an autosomal dominantly inherited genetic disorder that chiefly affects the central nervous system, along with the other multiple systems. While phenomenology and symptom severity may vary greatly from one individual to another, the most common neurological presentation is epilepsy, which may be refractory in a considerable number of patients. Convulsive SE is seen frequently in TSC patients due to the high ratio of refractory seizures in well-studied cohorts. Status epilepticus (SE) is a life-threating condition and requires urgent medical care. Non-convulsive status epilepticus (NCSE) is an epileptic state with no convulsive seizures but impaired consciousness and corresponding electrophysiological findings. Due to its heterogeneity of clinical features, it is generally hard to recognize, and thus difficult to treat promptly. The relationship between TSC and NCSE is a relatively less emphasized issue in the literature. Here, we present two cases of TSC with NCSE with a view to increasing clinicians' awareness of the association between refractory epilepsy and NCSE.

General Trends in Prices and Prescription Patterns of Anticonvulsants in Germany between 2000 and 2017: Analysis of National and Cohort-Based Data

OBJECTIVE

Our aim was to explore trends in price evolution and prescription volumes of anticonvulsants (AEDs, antiepileptic drugs) in Germany between 2000 and 2017.

METHOD

This study used data from annual reports on mean prescription frequency and prices of defined daily doses (DDD) of AEDs in Germany to analyze nationwide trends. Interrupted time series (ITS) analysis was employed to test for significant effects of several statutory healthcare reforms in Germany on AED price evolution. These data were compared to cohort-based prescription patterns of four German cohort studies from 2003, 2008, 2013, and 2016 that included a total of 1368 patients with focal and generalized epilepsies.

RESULTS

Analysis of national prescription data between 2000 and 2017 showed that mean prices per DDD of third-generation AEDs decreased by 65% and mean prices of second-generation AEDs decreased by 36%, whereas mean prices of first-generation AEDs increased by 133%. Simultaneously, mean prescription frequency of third- generation AEDs increased by 2494%, while there was a substantial decrease in the use of first- (- 55%) and second- (- 16%) generation AEDs. ITS analysis revealed that in particular the introduction of mandatory rebates on drugs in 2003 affected prices of frequently used newer AEDs. These findings are consistent with data from cohort studies of epilepsy patients showing a general decrease of prices for frequently used AEDs in monotherapy by 62% and in combination therapies by 68%. The analysis suggests that overall expenses for AEDs remained stable despite an increase in the prescription of "newer" and "non-enzyme-inducing" AEDs for epilepsy patients.

CONCLUSION

Between 2000 and 2017, a distinct decline in AED prices can be observed that seems predominately caused by a governmentally obtained price decline of third- and second-generation drugs. These observations seem to be the result of a German statutory cost containment policy applied across all health-care sectors. The increasing use of third-generation AEDs to the disadvantage of "old" and "enzyme-inducing" AEDs reflects the preferences of physicians and patients with epilepsy and follows national treatment guidelines.

Novel SZT2 mutations in three patients with developmental and epileptic encephalopathies

BACKGROUND

The seizure threshold 2 (SZT2) gene encodes a large, highly conserved protein that lowers seizure threshold and may also enhance epileptogenesis. In this study, three patients diagnosed with SZT2-related developmental and epileptic encephalopathies (DEEs) were reviewed aiming to expand knowledge of the genotype and phenotype of SZT2 mutations.

METHODS

Targeted next-generation sequencing was performed to identify pathogenic mutations in 205 cases with DEEs of unknown etiology. Detailed clinical and genetic data were collected from SZT2-associated patients.

RESULTS

Four novel mutations were found (c.1626 + 1G>A, c.5772dupA, c.4209C > A, c.7307_7308insG) in three patients. All the variants were inherited from their parents. Two patients were siblings and harbored the same mutations and presented developmental delay prior to the onset of seizures. All the individuals were diagnosed as DEEs, drug refractory epilepsy, and experienced status epilepticus (SE); one patient died of SE. One subject showed subependymal nodules as similar as those of tuberous sclerosis complex (TSC) in cranial magnetic resonance imaging (MRI).

CONCLUSION

Our results expand the genotype and phenotypes of SZT2-related DEEs, suggesting that SZT2 mutations play a role in developmental delay and epileptic encephalopathy, with high susceptibility to SE and relatively specific MRI findings.

Safety and efficacy of mTOR inhibitor treatment in patients with tuberous sclerosis complex under 2 years of age - a multicenter retrospective study

Background

Tuberous sclerosis complex (TSC) is a multisystem disease with prominent neurologic manifestations such as epilepsy, cognitive impairment and autism spectrum disorder. mTOR inhibitors have successfully been used to treat TSC-related manifestations in older children and adults. However, data on their safety and efficacy in infants and young children are scarce. The objective of this study is to assess the utility and safety of mTOR inhibitor treatment in TSC patients under the age of 2 years.

Results

A total of 17 children (median age at study inclusion 2.4 years, range 0–6; 12 males, 5 females) with TSC who received early mTOR inhibitor therapy were studied. mTOR inhibitor treatment was started at a median age of 5 months (range 0–19 months). Reasons for initiation of treatment were cardiac rhabdomyomas (6 cases), subependymal giant cell astrocytomas (SEGA, 5 cases), combination of cardiac rhabdomyomas and SEGA (1 case), refractory epilepsy (4 cases) and disabling congenital focal lymphedema (1 case). In all cases everolimus was used. Everolimus therapy was overall well tolerated. Adverse events were classified according to the Common Terminology Criteria of Adverse Events (CTCAE, Version 5.0). Grade 1–2 adverse events occurred in 12 patients and included mild transient stomatitis (2 cases), worsening of infantile acne (1 case), increases of serum cholesterol and triglycerides (4 cases), changes in serum phosphate levels (2 cases), increase of cholinesterase (2 cases), transient neutropenia (2 cases), transient anemia (1 case), transient lymphopenia (1 case) and recurrent infections (7 cases). No grade 3–4 adverse events were reported. Treatment is currently continued in 13/17 patients. Benefits were reported in 14/17 patients and included decrease of cardiac rhabdomyoma size and improvement of arrhythmia, decrease of SEGA size, reduction of seizure frequency and regression of congenital focal lymphedema. Despite everolimus therapy, two patients treated for intractable epilepsy are still experiencing seizures and another one treated for SEGA showed no volume reduction.

Conclusion

This retrospective multicenter study demonstrates that mTOR inhibitor treatment with everolimus is safe in TSC patients under the age of 2 years and shows beneficial effects on cardiac manifestations, SEGA size and early epilepsy.