Cortical dysplasia and autistic trait severity in children with Tuberous Sclerosis Complex: a clinical epidemiological study.

Tuberous Sclerosis Complex (TSC) is characterized by a high prevalence of autism spectrum disorders (ASD). Little is known about the relation between cortical dysplasia and ASD severity in TSC. We assessed ASD severity (using the Autism Diagnostic Observation Scale), tuber and radial migration line (RML) count and location, and cognitive functioning in 52 children with TSC and performed regression and mediation analyses. Tuber and RML count were strongly positively related to ASD severity. However, when correcting for cognitive functioning, the majority of associations became insignificant and only total tuber count remained associated to the severity of restricted/repetitive behaviors. Occipital RML count remained associated with overall ASD severity, and social communication/interaction deficit severity specifically. This study shows the important explanatory role of cognitive functioning in the association between cortical dysplasia and ASD severity, and the relevance of separately studying the two ASD subdomains.

Epilepsy in children with tuberous sclerosis complex: Chance of remission and response to antiepileptic drugs.

OBJECTIVE: To describe treatment and outcome of epilepsy in children with tuberous sclerosis complex (TSC). METHODS: Seventy-one children with TSC and epilepsy treated at the ENCORE TSC Expertise Center between 1988 and 2014 were included. Patient characteristics and duration and effectiveness of antiepileptic treatments were extracted from our clinical database. Correlations were made between recurrence of seizures after response to treatment, and several patient characteristics. RESULTS: Median age at time of inclusion was 9.4 years (range 0.9-18.0). Seizure history showed that 55 children (77%) of 71 became seizure-free for longer than 1 month, and 21 (30%) of 71 for longer than 24 months. Remission of seizures was associated with higher IQ, and a trend was observed between seizure remission and age at onset of seizures. A total of 19 antiepileptic drugs (AEDs) were used. Valproic acid, vigabatrin, levetiracetam, and carbamazepine were used most frequently. Nonpharmacologic therapies (ketogenic diet, epilepsy surgery, and vagus nerve stimulation) were used 13 times. Epilepsy surgery was most effective, with four of five children becoming seizure-free. AEDs prescribed as first and second treatment were most effective. Valproic acid was prescribed most frequently as first and second treatment, followed by vigabatrin. Thirty-one children had infantile spasms, preceded by focal seizures in 18 children (58%). Vigabatrin was used by 29 children (94%), and was first treatment in 15 (48%). Vigabatrin was more effective than other AEDs when prescribed as first treatment. SIGNIFICANCE: We showed that, although 77% of children with epilepsy due to TSC reached seizure remission, usually after their first or second AED, this was sustained for at least 24 months in only 38%. Almost half of those with 24 months of remission later had relapse of seizures. Our results support vigabatrin as first choice drug, and show the need for better treatment options for these children.

TORC1-dependent epilepsy caused by acute biallelic Tsc1 deletion in adult mice.

OBJECTIVE: Seizure development in tuberous sclerosis complex (TSC) correlates with the presence of specific lesions called cortical tubers. Moreover, heterozygous TSC animal models do not show gross brain pathology and are seizure-free, suggesting that such pathology is a prerequisite for the development of epilepsy. However, cells within TSC lesions show increased activity of the target of rapamycin complex 1 (TORC1) pathway, and recent studies have implicated this pathway in non-TSC-related animal models of epilepsy and neuronal excitability. These findings imply a direct role for TORC1 in epilepsy. Here, we investigate the effect of increased TORC1 signaling induced by acute biallelic deletion of Tsc1 in healthy adult mice. METHODS: Biallelic Tsc1 gene deletion was induced in adult Tsc1 heterozygous and wild-type mice. Seizures were monitored by electroencephalographic and video recordings. Molecular and cellular changes were investigated by Western blot analysis, immunohistochemistry, and electrophysiology. RESULTS: Mice developed epilepsy a few days after biallelic Tsc1 deletion. Acute gene deletion was not accompanied by any obvious histological changes, but resulted in activation of the TORC1 pathway, enhanced neuronal excitability, and a decreased threshold for protein-synthesis-dependent long-term potentiation preceding the onset of seizures. Rapamycin treatment after seizure onset reduced TORC1 activity and fully abolished the seizures. INTERPRETATION: Our data indicate a direct role for TORC1 signaling in epilepsy development, even in the absence of major brain pathology. This suggests that TORC1 is a promising target for treating seizures not only in TSC but also in other forms of epilepsy that result from increased TORC1 activation.

Counselling in tuberous sclerosis complex: A survey on content and satisfaction in the Netherlands.

BACKGROUND: Tuberous sclerosis complex (TSC) is a highly variable condition and its clinical features cannot reliably be predicted from the genotype. Counselling of parents of a child with TSC is challenging because of the variability of the condition and the changing outlook due to new treatment options. This study explored current counselling strategies in TSC in the Netherlands, with the aim of developing a recommendation for counselling. METHOD: We performed a nationwide survey using digital questionnaires. Questionnaires were sent to parents of children diagnosed with TSC, and to medical doctors involved in counselling, both no more than ten years prior to the study. Questions focused on general information about the child with TSC, medical doctors involved in counselling, type of information provided, mode of providing information, and recommendations for improvement of counselling. RESULTS: Parents of 34 children diagnosed with TSC (7 prenatally) and 18 medical doctors from different departments responded to the questionnaires. Almost all parents were informed on the neurological and cardiac symptoms of TSC, other symptoms were mentioned less often. Satisfaction on counselling was higher when more information on the variability of TSC was provided, preferentially during a clinical visit, when emotional support was provided, and when parents were notified of the TSC patient society. CONCLUSIONS: Information on the variability in expression and quality of life is highly demanded by (expecting) parents of a child with TSC. Furthermore, reference should be made to institutions such as the support organisation for patients and social services for questions and support.

Everolimus for the treatment of refractory seizures associated with tuberous sclerosis complex (TSC): current perspectives.

Up to 90% of patients with tuberous sclerosis complex (TSC) have epilepsy, and in over half of patients seizure control cannot be achieved by regular antiepileptic drugs. The underlying problem is mTOR hyperactivation due to loss of function of the TSC proteins. Treatment with everolimus, an mTOR inhibitor, has been shown to be of great benefit to TSC patients, both in reducing tumor growth and as a treatment for intractable epilepsy. Up to 40% of TSC patients with intractable epilepsy show a clinically relevant seizure response to everolimus. It has not yet fully lived up to its promise as a disease-modifying drug, however, as half of TSC patients with intractable epilepsy do not show a clinically relevant seizure frequency reduction. There is no evidence yet of a positive effect on the cognitive and neuropsychiatric deficits in TSC patients. In preclinical studies, mTOR inhibition can rescue abnormal neuronal migration and synapse formation that is caused by mTOR hyperactivation. These studies show a critical time window that suggests that mTOR inhibition may be most beneficial in young children. The trials done so far have not studied treatment in children under 2 years of age, although case series suggest that the safety profile is similar to that in older children. Further studies into the optimal time window, dosing schedules and possibly combination with other drugs may further improve the benefit of everolimus for TSC patients.

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.

Sirolimus for epilepsy in children with tuberous sclerosis complex: A randomized controlled trial.

OBJECTIVE: To investigate whether mammalian target of rapamycin complex 1 (mTORC1) inhibitors could reduce seizure frequency in children with tuberous sclerosis complex (TSC). METHODS: Due to slow inclusion rate, target inclusion of 30 children was not reached. Twenty-three children with TSC and intractable epilepsy (age 1.8-10.9 years) were randomly assigned (1:1) to open-label, add-on sirolimus treatment immediately or after 6 months. Sirolimus was titrated to trough levels of 5-10 ng/mL. Primary endpoint was seizure frequency change during the sixth month of sirolimus treatment. RESULTS: Intention-to-treat analysis showed sirolimus treatment resulted in 41% seizure frequency decrease (95% confidence interval [CI] -69% to +14%; p = 0.11) compared to the standard-care period. Per protocol analysis of 14 children who reached sirolimus target trough levels in the sixth sirolimus month showed a seizure frequency decrease of 61% (95% CI -86% to +6%; p = 0.06). Cognitive development did not change. All children had adverse events. Five children discontinued sirolimus prematurely. CONCLUSIONS: We describe a randomized controlled trial for a non-antiepileptic drug that directly targets a presumed causal mechanism of epileptogenesis in a genetic disorder. Although seizure frequency decreased, especially in children reaching target trough levels, we could not show a significant benefit. Larger trials or meta-analyses are needed to investigate if patients with TSC with seizures benefit from mTORC1 inhibition. This trial was registered at trialregister.nl (NTR3178) and supported by the Dutch Epilepsy Foundation. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that sirolimus does not significantly reduce seizure frequency in children with TSC and intractable epilepsy. The study lacked the precision to exclude a benefit from sirolimus.

Genotype and brain pathology phenotype in children with tuberous sclerosis complex.

Structural brain malformations associated with Tuberous Sclerosis Complex (TSC) are related to the severity of the clinical symptoms and can be visualized by magnetic resonance imaging (MRI). Tuberous Sclerosis Complex is caused by inactivating TSC1 or TSC2 mutations. We investigated associations between TSC brain pathology and different inactivating TSC1 and TSC2 variants, and examined the potential prognostic value of subdivision of TSC2 variants based on their predicted effects on TSC2 expression. We performed genotype-phenotype associations of TSC-related brain pathology on a cohort of 64 children aged 1.4-17.9 years. Brain abnormalities were assessed using MRI. Individuals were grouped into those with an inactivating TSC1 variant and those with an inactivating TSC2 variant. The TSC2 group was subdivided into changes predicted to result in TSC2 protein expression (TSC2p) and changes predicted to prevent expression (TSC2x). The TSC2 group was associated with more and larger tubers, more radial migration lines, and more subependymal nodules than the TSC1 group. Subependymal nodules were also more likely to be calcified. Subdivision of the TSC2 group did not reveal additional, substantial differences, except for a larger number of tubers in the temporal lobe and a larger fraction of cystic tubers in the TSC2x subgroup. The severity of TSC-related brain pathology was related to the presence of an inactivating TSC2 variant. Although larger studies might find specific TSC2 variants that have prognostic value, in our cohort, subdivision of the TSC2 group did not lead to better prediction.

Treatment of Cognitive Deficits in Genetic Disorders: A Systematic Review of Clinical Trials of Diet and Drug Treatments.

IMPORTANCE: Knowing the underlying etiology of intellectual disability in genetic disorders holds great promise for developing targeted treatments. Although successful preclinical studies and many positive clinical studies have been reported, it is unclear how many purported therapies have become established treatments. The quality of the clinical trials may be an important determinant for achieving clinical impact. OBJECTIVE: To evaluate clinical impact, strengths, and weaknesses of clinical trials of diet or drug treatments to improve cognitive function in patients with a genetic disorder. EVIDENCE REVIEW: MEDLINE, EMBASE, PsycINFO, and Cochrane databases were searched from inception date to January 26, 2014, for clinical trials with cognitive outcomes in patients with genetic disorders. Outcome measures of randomized clinical trials (RCTs) were compared between trial registries and reports, and trials were evaluated for the quality of design using the Jadad score and Consolidated Standards of Reporting Trials (CONSORT) criteria. FINDINGS: We identified 169 trial reports of 80 treatments for 32 genetic disorders. Seventy-five trials (44.4%) reported potential efficacy, of which only 2 therapies are now established treatments, namely, dietary restriction for phenylketonuria and miglustat for Niemann-Pick disease type C. The median sample size for RCTs was 25 (range, 2-537). Only 30 of 107 RCTs (28.0%) had acceptable Jadad scores exceeding 3. Reporting of key CONSORT items was poor. Reported outcome measures matched preregistered outcome measures in trial registries in only 5 of 107 RCTs (4.7%). CONCLUSIONS AND RELEVANCE: The number of trials in the field of cognitive genetic disorders is rapidly growing, but clinical impact has been limited because few drugs have become established treatments and the benefit of most drugs remains unclear. Most trials have small sample sizes and low quality of design. Predefinition of outcome measures, improved trial reporting and design, and international collaboration to increase recruitment are needed to unequivocally determine efficacy of drugs identified in preclinical research.