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Richard MA, Lupo PJ, Ehli EA, Sahin M, Krueger DA, Wu JY, Bebin EM, Au KS, Northrup H, Farach LS. Common epilepsy variants from the general population are not associated with epilepsy among individuals with tuberous sclerosis complex. Am J Med Genet A 2024; 194:e63569. [PMID: 38366765 PMCID: PMC11060940 DOI: 10.1002/ajmg.a.63569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/26/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
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.
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Affiliation(s)
- Melissa A Richard
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas, USA
| | - Philip J Lupo
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas, USA
| | - Erik A Ehli
- Avera Institute for Human Genetics, Sioux Falls, South Dakota, USA
| | - Mustafa Sahin
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Darcy A Krueger
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Joyce Y Wu
- Epilepsy Center, Division of Pediatric Neurology, Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
- Department of Pediatrics, Division of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Elizabeth M Bebin
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kit Sing Au
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Hope Northrup
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Laura S Farach
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
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Farach LS, Northrup H, Nellist M, van Unen L, Hillman P, Klonowska K, Ekong R, Crino PB, Sing Au K. Mild TSC Phenotype and Non-Penetrance Associated with a Frameshift Variant in TSC2 Prompts Caution in Evaluating Pathogenicity of Frameshift Variants. Gene 2023:147566. [PMID: 37311496 DOI: 10.1016/j.gene.2023.147566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/06/2023] [Accepted: 06/09/2023] [Indexed: 06/15/2023]
Abstract
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.
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Affiliation(s)
- Laura S Farach
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA.
| | - Hope Northrup
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Leontine van Unen
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Paul Hillman
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA
| | - Katarzyna Klonowska
- Cancer Genetics Laboratory, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Rosemary Ekong
- Research Department of Genetics, Evolution and Environment, Darwin Building, University College London, London, United Kingdom
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kit Sing Au
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA
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Genetic pathogenesis of the epileptogenic lesions in Tuberous Sclerosis Complex: Therapeutic targeting of the mTOR pathway. Epilepsy Behav 2022; 131:107713. [PMID: 33431351 DOI: 10.1016/j.yebeh.2020.107713] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/14/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022]
Abstract
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.
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Capal JK, Williams ME, Pearson DA, Kissinger R, Horn PS, Murray D, Currans K, Kent B, Bebin M, Northrup H, Wu JY, Sahin M, Krueger DA. Profile of Autism Spectrum Disorder in Tuberous Sclerosis Complex: Results from a Longitudinal, Prospective, Multisite Study. Ann Neurol 2021; 90:874-886. [PMID: 34668231 DOI: 10.1002/ana.26249] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 10/13/2021] [Accepted: 10/13/2021] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Tuberous sclerosis complex (TSC) is highly associated with autism spectrum disorder (ASD). Objectives of the study were to characterize autistic features in young children with TSC. METHODS Participants included 138 children followed from ages 3 to 36 months with TSC from the Tuberous Sclerosis Complex Autism Center of Excellence Research Network (TACERN), a multicenter, prospective observational study aimed at understanding the underlying mechanisms of ASD in TSC. Developmental and autism-specific assessments were administered, and a clinical diagnosis of ASD was determined for all participants at 36 months. Further analyses were performed on 117 participants with valid autism assessments based on nonverbal mental age greater than 15 months. RESULTS Prevalence of clinical diagnosis of ASD at 36 months was 25%. Nearly all autistic behaviors on the Autism Diagnostic Observation Schedule-2 (ADOS-2) and Autism Diagnostic Interview-Revised (ADI-R) were more prevalent in children diagnosed with ASD; however, autism-specific behaviors were also observed in children without ASD. Overall quality of social overtures, facial expressions, and abnormal repetitive interests and behaviors were characteristics most likely to distinguish children with ASD from those without an ASD diagnosis. Participants meeting ADOS-2 criteria but not a clinical ASD diagnosis exhibited intermediate developmental and ADOS-2 scores compared to individuals with and without ASD. INTERPRETATION ASD is highly prevalent in TSC, and many additional individuals with TSC exhibit a broad range of subthreshold autistic behaviors. Our findings reveal a broader autism phenotype that can be identified in young children with TSC, which provides opportunity for early targeted treatments. ANN NEUROL 2021.
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Affiliation(s)
- Jamie K Capal
- University of North Carolina at Chapel Hill, Chapel Hill, NC
- Department of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Marian E Williams
- Keck School of Medicine of USC, University of Southern California, Children's Hospital Los Angeles, Los Angeles, CA
| | - Deborah A Pearson
- McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX
| | - Robin Kissinger
- Keck School of Medicine of USC, University of Southern California, Children's Hospital Los Angeles, Los Angeles, CA
| | - Paul S Horn
- Department of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Donna Murray
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
- Department of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
- Autism Speaks Inc, Boston, MA
| | - Kristn Currans
- Department of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Bridget Kent
- Department of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Martina Bebin
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL
| | - Hope Northrup
- McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX
| | - Joyce Y Wu
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Mustafa Sahin
- Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA
| | - Darcy A Krueger
- Department of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
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Prediction of tuberous sclerosis-associated neurocognitive disorders and seizures via machine learning of structural magnetic resonance imaging. Neuroradiology 2021; 64:611-620. [PMID: 34532765 DOI: 10.1007/s00234-021-02789-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/06/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Tuberous sclerosis complex (TSC) is a genetic disorder characterized by multiorgan hamartomas, including cerebral lesions, with seizures as a common presentation. Most TSC patients will also experience neurocognitive comorbidities. Our objective was to use machine learning techniques incorporating clinical and imaging data to predict the occurrence of major neurocognitive disorders and seizures in TSC patients. METHODS A cohort of TSC patients were enrolled in this retrospective study. Clinical data included genetic, demographic, and seizure characteristics. Imaging parameters included the number, characteristics, and location of cortical tubers and the presence of subependymal nodules, SEGAs, and cerebellar tubers. A random forest machine learning scheme was used to predict seizures and neurodevelopmental delay or intellectual developmental disability. Prediction ability was assessed by the area-under-the-curve of receiver-operating-characteristics (AUC-ROC) of ten-fold cross-validation training set and an independent validation set. RESULTS The study population included 77 patients, 55% male (17.1 ± 11.7 years old). The model achieved AUC-ROC of 0.72 ± 0.1 and 0.68 in the training and internal validation datasets, respectively, for predicting neurocognitive comorbidity. Performance was limited in predicting seizures (AUC-ROC of 0.54 ± 0.19 and 0.71 in the training and internal validation datasets, respectively). The integration of seizure characteristics into the model improved the prediction of neurocognitive comorbidity with AUC-ROC of 0.84 ± 0.07 and 0.75 in the training and internal validation datasets, respectively. CONCLUSIONS This proof of concept study shows that it is possible to achieve a reasonable prediction of major neurocognitive morbidity in TSC patients using structural brain imaging and machine learning techniques. These tools can help clinicians identify subgroups of TSC patients with an increased risk of developing neurocognitive comorbidities.
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Lobanov OV, Shimony JS, Kenley J, Kaplan S, Alexopoulos D, Roland JL, Smyth MD, Smyser CD. Alterations in resting-state functional connectivity in pediatric patients with tuberous sclerosis complex. Epilepsia Open 2021; 6:579-587. [PMID: 34268913 PMCID: PMC8408601 DOI: 10.1002/epi4.12523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/28/2021] [Accepted: 06/27/2021] [Indexed: 02/03/2023] Open
Abstract
Objective To investigate resting‐state functional connectivity (FC) in pediatric patients with tuberous sclerosis complex and intractable epilepsy requiring surgery. Methods Resting‐state functional MRI was utilized to investigate functional connectivity in 13 pediatric patients with tuberous sclerosis complex (TSC) and intractable epilepsy requiring surgery. Results The majority of patients demonstrated a resting‐state network architecture similar to those reported in healthy individuals. However, preoperative differences were evident between patients with high versus low tuber burden, as well as those with good versus poor neurodevelopmental outcomes, most notably in the cingulo‐opercular and visual resting‐state networks. One patient with high tuber burden and poor preoperative development and seizure control had nearly normal development and seizure resolution after surgery. This was accompanied by significant improvement in resting‐state network architecture just one day postoperatively. Significance Although many patients with tuberous sclerosis complex and medically refractory epilepsy demonstrate functional connectivity patterns similar to healthy children, relationships within and between RSNs demonstrate clear differences in patients with higher tuber burden and worse outcomes. Improvements in resting‐state network organization postoperatively may be related to epilepsy surgery outcomes, providing candidate biomarkers for clinical management in this high‐risk population.
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Affiliation(s)
- Oleg V Lobanov
- Department of Neurology, Washington University, St. Louis, MO, USA
| | - Joshua S Shimony
- Department of Radiology, Washington University, St. Louis, MO, USA
| | - Jeanette Kenley
- Department of Neurology, Washington University, St. Louis, MO, USA
| | - Sydney Kaplan
- Department of Neurology, Washington University, St. Louis, MO, USA
| | | | - Jarod L Roland
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Matthew D Smyth
- Department of Neurological Surgery, Washington University, St. Louis, MO, USA.,Department of Pediatrics, Washington University, St. Louis, MO, USA
| | - Christopher D Smyser
- Department of Neurology, Washington University, St. Louis, MO, USA.,Department of Radiology, Washington University, St. Louis, MO, USA.,Department of Pediatrics, Washington University, St. Louis, MO, USA
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Mitchell RA, Barton SM, Harvey AS, Ure AM, Williams K. Factors associated with autism spectrum disorder in children with tuberous sclerosis complex: a systematic review and meta-analysis. Dev Med Child Neurol 2021; 63:791-801. [PMID: 33432576 DOI: 10.1111/dmcn.14787] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/13/2020] [Indexed: 12/21/2022]
Abstract
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.
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Affiliation(s)
- Rebecca A Mitchell
- Department of Neurodevelopment and Disability, The Royal Children's Hospital, Parkville, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia.,Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - Sarah M Barton
- Murdoch Children's Research Institute, Parkville, VIC, Australia.,Department of Neurology, The Royal Children's Hospital, Parkville, VIC, Australia
| | - A Simon Harvey
- Murdoch Children's Research Institute, Parkville, VIC, Australia.,Department of Neurology, The Royal Children's Hospital, Parkville, VIC, Australia
| | - Alexandra M Ure
- Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia.,Murdoch Children's Research Institute, Parkville, VIC, Australia.,Mental Health, The Royal Children's Hospital, Parkville, VIC, Australia.,Paediatrics and Education Research, Monash University, Clayton, VIC, Australia
| | - Katrina Williams
- Department of Neurodevelopment and Disability, The Royal Children's Hospital, Parkville, VIC, Australia.,Paediatrics and Education Research, Monash University, Clayton, VIC, Australia.,Monash Health, Monash Children's Hospital, Clayton, VIC, Australia
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Farach LS, Richard MA, Lupo PJ, Sahin M, Krueger DA, Wu JY, Bebin EM, Au KS, Northrup H. Epilepsy Risk Prediction Model for Patients With Tuberous Sclerosis Complex. Pediatr Neurol 2020; 113:46-50. [PMID: 33011641 PMCID: PMC10461434 DOI: 10.1016/j.pediatrneurol.2020.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/29/2020] [Accepted: 07/25/2020] [Indexed: 01/13/2023]
Abstract
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.
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Affiliation(s)
- Laura S Farach
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas.
| | - Melissa A Richard
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Philip J Lupo
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Mustafa Sahin
- Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Darcy A Krueger
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Joyce Y Wu
- Division of Pediatric Neurology, UCLA Mattel Children's Hospital and David Geffen School of Medicine, Los Angeles, California
| | | | - Kit Sing Au
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Hope Northrup
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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Specchio N, Pietrafusa N, Trivisano M, Moavero R, De Palma L, Ferretti A, Vigevano F, Curatolo P. Autism and Epilepsy in Patients With Tuberous Sclerosis Complex. Front Neurol 2020; 11:639. [PMID: 32849171 PMCID: PMC7431762 DOI: 10.3389/fneur.2020.00639] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/29/2020] [Indexed: 12/27/2022] Open
Abstract
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.
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Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
- Member of European Reference Network EpiCARE
| | - Nicola Pietrafusa
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Marina Trivisano
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Romina Moavero
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Rome, Italy
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Luca De Palma
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Alessandro Ferretti
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Federico Vigevano
- Member of European Reference Network EpiCARE
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Rome, Italy
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Toldo I, Bugin S, Perissinotto E, Pelizza MF, Vignoli A, Parazzini C, Canevini MP, Nosadini M, Sartori S, Manara R. Cerebellar lesions as potential predictors of neurobehavioural phenotype in tuberous sclerosis complex. Dev Med Child Neurol 2019; 61:1221-1228. [PMID: 31313298 DOI: 10.1111/dmcn.14313] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/21/2019] [Indexed: 11/30/2022]
Abstract
AIM To improve the genetic, clinical, and neuroradiological characterization of cerebellar involvement in tuberous sclerosis complex (TSC) and determine whether cerebellar lesions could be a reliable biomarker of neurological impairment. METHOD This retrospective cohort study, held at two tertiary paediatric university centres, was conducted on patients with a confirmed diagnosis of TSC who underwent brain magnetic resonance imaging between October 2009 and May 2016. The study population consisted of 112 patients with TSC (median age 10y; range 5mo-38y; 61 females, 51 males). RESULTS The results from multivariable statistical analysis indicated that cerebellar involvement (34 out of 112 patients, none carrying a TSC1 mutation) was the most powerful predictor of supratentorial cortical tuber load; however, cerebellar involvement was not the best predictor of clinical phenotype when supratentorial tuber load and TSC2 mutations were taken into consideration. The association between cerebellar lesions and a more severe clinical and neuroradiological phenotype was statistically significant and may be due to its strong association with TSC2 mutations and higher cortical tuber load. INTERPRETATION Cerebellar involvement is not the best predictor of neurobehavioural outcome, including TSC-related autism, after adjusting for TSC2 and the number of cortical tubers. Its role in the TSC clinical phenotype needs to be investigated further. WHAT THIS PAPER ADDS Cerebellar involvement is a powerful predictor of supratentorial cortical involvement and a potential biomarker of disease severity. Cerebellar lesions significantly correlate with a more severe clinical and neuroradiological phenotype. Cerebellar involvement is not the best predictor of neurobehavioural outcome.
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Affiliation(s)
- Irene Toldo
- Pediatric Neurology and Neurophysiology Unit, Department of Woman's and Child's Health, University of Padua, Padua, Italy
| | - Samuela Bugin
- Pediatric Neurology and Neurophysiology Unit, Department of Woman's and Child's Health, University of Padua, Padua, Italy
| | - Egle Perissinotto
- Unit of Biostatistics, Epidemiology and Public Health, Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padua, Padua, Italy
| | - Maria Federica Pelizza
- Pediatric Neurology and Neurophysiology Unit, Department of Woman's and Child's Health, University of Padua, Padua, Italy
| | - Aglaia Vignoli
- Neuropsychiatric Unit, Health Sciences Department, Epilepsy Center, ASST Santi Paolo Carlo, University of Milan, Milan, Italy
| | - Cecilia Parazzini
- Department of Pediatric Radiology and Neuroradiology, Children's Hospital "V. Buzzi", Milan, Italy
| | - Maria Paola Canevini
- Neuropsychiatric Unit, Health Sciences Department, Epilepsy Center, ASST Santi Paolo Carlo, University of Milan, Milan, Italy
| | - Margherita Nosadini
- Pediatric Neurology and Neurophysiology Unit, Department of Woman's and Child's Health, University of Padua, Padua, Italy
| | - Stefano Sartori
- Pediatric Neurology and Neurophysiology Unit, Department of Woman's and Child's Health, University of Padua, Padua, Italy
| | - Renzo Manara
- Neuroradiology Unit, University of Salerno, Salerno, Italy
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11
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Mühlebner A, Bongaarts A, Sarnat HB, Scholl T, Aronica E. New insights into a spectrum of developmental malformations related to mTOR dysregulations: challenges and perspectives. J Anat 2019; 235:521-542. [PMID: 30901081 DOI: 10.1111/joa.12956] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2019] [Indexed: 12/20/2022] Open
Abstract
In recent years the role of the mammalian target of rapamycin (mTOR) pathway has emerged as crucial for normal cortical development. Therefore, it is not surprising that aberrant activation of mTOR is associated with developmental malformations and epileptogenesis. A broad spectrum of malformations of cortical development, such as focal cortical dysplasia (FCD) and tuberous sclerosis complex (TSC), have been linked to either germline or somatic mutations in mTOR pathway-related genes, commonly summarised under the umbrella term 'mTORopathies'. However, there are still a number of unanswered questions regarding the involvement of mTOR in the pathophysiology of these abnormalities. Therefore, a monogenetic disease, such as TSC, can be more easily applied as a model to study the mechanisms of epileptogenesis and identify potential new targets of therapy. Developmental neuropathology and genetics demonstrate that FCD IIb and hemimegalencephaly are the same diseases. Constitutive activation of mTOR signalling represents a shared pathogenic mechanism in a group of developmental malformations that have histopathological and clinical features in common, such as epilepsy, autism and other comorbidities. We seek to understand the effect of mTOR dysregulation in a developing cortex with the propensity to generate seizures as well as the aftermath of the surrounding environment, including the white matter.
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Affiliation(s)
- A Mühlebner
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - A Bongaarts
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - H B Sarnat
- Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute (Owerko Centre), Calgary, AB, Canada
| | - T Scholl
- Department of Paediatric and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - E Aronica
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Amsterdam, The Netherlands
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12
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Cox RL, Calderon de Anda F, Mangoubi T, Yoshii A. Multiple Critical Periods for Rapamycin Treatment to Correct Structural Defects in Tsc-1-Suppressed Brain. Front Mol Neurosci 2018; 11:409. [PMID: 30467464 PMCID: PMC6237075 DOI: 10.3389/fnmol.2018.00409] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 10/18/2018] [Indexed: 11/18/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant neurogenetic disorder affecting the brain and other vital organs. Neurological symptoms include epilepsy, intellectual disability, and autism. TSC is caused by a loss-of-function mutation in the TSC1 or TSC2 gene. These gene products form a protein complex and normally suppress mammalian target of rapamycin (mTOR) activity. mTOR inhibitors have been used to treat subependymal glioma (SEGA) that is a brain tumor characteristic of TSC. However, neuropathology of TSC also involves dysregulated cortical circuit formation including neuronal migration, axodendritic differentiation, and synapse formation. It is currently unknown to what extent mTOR signaling inhibitors correct an alteration in neuronal morphology that have already formed prior to the treatment. Here, we address the efficacy of rapamycin treatment on neuronal migration and dendrite formation. Using in utero electroporation, we suppressed Tsc1 expression in a fraction of neuronal progenitor cells during the fetal period. In embryonic brain slices, we found that more Tsc1-suppressed cells remained within the periventricular zone, and rapamycin treatment facilitated neuronal migration. Postnatally, Tsc1-suppressed pyramidal neurons showed more complex branching of basal dendrites and a higher spine density at postnatal day (P) 28. Aberrant arborization was normalized by rapamycin administration every other day between P1 and P13 but not P15 and P27. In contrast, abnormal spine maturation improved by rapamycin treatment between P15 and P27 but not P1 and P13. Our results indicate that there are multiple critical windows for correcting different aspects of structural abnormalities in TSC, and the responses depend on the stage of neuronal circuit formation. These data warrant a search for an additional therapeutic target to treat neurological symptoms of TSC.
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Affiliation(s)
- Rebecca L Cox
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, United States
| | - Froylan Calderon de Anda
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Center for Molecular Neurobiology Hamburg, Research Group Neuronal Development, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tomer Mangoubi
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Akira Yoshii
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Anatomy & Cell Biology, University of Illinois at Chicago, Chicago, IL, United States
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13
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Abstract
The mechanistic target of rapamycin (mTOR) is an important signaling hub that integrates environmental information regarding energy availability and stimulates anabolic molecular processes and cell growth. Abnormalities in this pathway have been identified in several syndromes in which autism spectrum disorder (ASD) is highly prevalent. Several studies have investigated mTOR signaling in developmental and neuronal processes that, when dysregulated, could contribute to the development of ASD. Although many potential mechanisms still remain to be fully understood, these associations are of great interest because of the clinical availability of mTOR inhibitors. Clinical trials evaluating the efficacy of mTOR inhibitors to improve neurodevelopmental outcomes have been initiated.
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Affiliation(s)
- Kellen D. Winden
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Darius Ebrahimi-Fakhari
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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14
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Jesmanas S, Norvainytė K, Gleiznienė R, Šimoliūnienė R, Endzinienė M. Different MRI-defined tuber types in tuberous sclerosis complex: Quantitative evaluation and association with disease manifestations. Brain Dev 2018; 40:196-204. [PMID: 29258718 DOI: 10.1016/j.braindev.2017.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 11/23/2017] [Accepted: 11/28/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is a rare genetic disorder with multisystem involvement. A magnetic-resonance (MRI) based classification of tubers into types A, B and C has been proposed. However, the relationship between different tuber types and their quantitative characteristics, also the non-neurological manifestations of TSC remains unknown. AIMS To quantitatively evaluate different MRI-defined tuber types and to explore their relationships with major disease manifestations in patients with tuberous sclerosis complex. METHODS We performed quantitative manual assessment of tubers visible on T1W, T2W/FLAIR images and DW/ADC maps of 20 patients with TSC. Tubers were classified into types A, B and C based on their signal intensity on MRI. General clinical information and quantitative tuber characteristics were evaluated. Between-group comparisons were made using the nonparametric Mann-Whitney U test with Bonferroni correction. RESULTS In total, 20 patients with 770 tubers were evaluated. Type A tubers were most numerous followed closely by Type B tubers, whereas Type C tubers were relatively rare. Tuber size was markedly different among the three tuber types: it increased from Type A to Type B to Type C. Infantile spasms, generalized-tonic clonic seizures, poor seizure control, cardiac rhabdomyomas, SEGA and developmental delay were not associated with quantitative tuber characteristics. Increased total Type B tuber load was associated with early onset epilepsy, while individually larger Type A and Type B tubers were associated with the presence angiomyolipoma (AML) and renal cysts. CONCLUSIONS MRI-defined tuber types differ significantly in their size and number. Larger total Type B tuber load and larger individual Type A and Type B tubers were found to be most associated with early seizure onset and renal angiomyolipomas, respectively. One possible explanation for the observed differences in the clinical phenotype based on MRI-defined tuber types is not the intrinsic qualitative distinctions between different tuber types, but rather their individual size and total tuber load.
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Affiliation(s)
- Simonas Jesmanas
- Faculty of Medicine, Medical Academy, Lithuanian University of Health Sciences, Lithuania
| | - Kristina Norvainytė
- Faculty of Medicine, Medical Academy, Lithuanian University of Health Sciences, Lithuania
| | - Rymantė Gleiznienė
- Radiology Department, Medical Academy, Lithuanian University of Health Sciences, Lithuania
| | - Renata Šimoliūnienė
- Department of Physics, Mathematics and Biophysics, Medical Academy, Lithuanian University of Health Sciences, Lithuania
| | - Milda Endzinienė
- Neurology Department, Medical Academy, Lithuanian University of Health Sciences, Lithuania.
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15
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Sundberg M, Sahin M. Cerebellar Development and Autism Spectrum Disorder in Tuberous Sclerosis Complex. J Child Neurol 2015; 30:1954-62. [PMID: 26303409 PMCID: PMC4644486 DOI: 10.1177/0883073815600870] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 07/15/2015] [Indexed: 01/08/2023]
Abstract
Approximately 50% of patients with the genetic disease tuberous sclerosis complex present with autism spectrum disorder. Although a number of studies have investigated the link between autism and tuberous sclerosis complex, the etiology of autism spectrum disorder in these patients remains unclear. Abnormal cerebellar function during critical phases of development could disrupt functional processes in the brain, leading to development of autistic features. Accordingly, the authors review the potential role of cerebellar dysfunction in the pathogenesis of autism spectrum disorder in tuberous sclerosis complex. The authors also introduce conditional knockout mouse models of Tsc1 and Tsc2 that link cerebellar circuitry to the development of autistic-like features. Taken together, these preclinical and clinical investigations indicate the cerebellum has a profound regulatory role during development of social communication and repetitive behaviors.
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Affiliation(s)
- Maria Sundberg
- The F.M. Kirby Neurobiology Center, Department of Neurology, Children’s Hospital Boston, Harvard Medical School, Boston, MA, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Department of Neurology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
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16
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Wong VCN, Fung CW, Lee SL, Wong PTY. Review of evolution of clinical, training and educational services and research program for autism spectrum disorders in Hong Kong. SCIENCE CHINA-LIFE SCIENCES 2015; 58:991-1009. [PMID: 26335731 DOI: 10.1007/s11427-012-4294-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The evolution of a local fragmented model of services for children with autism in Hong Kong emerged gradually over the past three decades with lack of government funding or support. This had been due to increasing number of children with autism being detected and referred for earlier assessment. With increasing pressure from parents due to long waiting time for assessment and training services and the increasing polarization by mass media there had been a gradual increasing public awareness over the past five years. Though still highly fragmented in the availability of services, there is a growing "business model" available in the community due to increasing need and lack of public funding for support. There is a lack of strategic planning for medical diagnostic and management issues in Hong Kong. Our University of Hong Kong based Autism Research Program was pioneered in 1985 based on the increasing load of autism cases referred for assessment for other developmental problems and diagnosed as Autism in the Duchess of Kent Children's Hospital. As the first author has been the staff of the University of Hong Kong, this program flourished as a research based program. The benefits of early identification and intervention of autism spectrum disorder (ASD) had been increasingly recognized, and with the increased public awareness and increasing trend of earlier diagnosis, there has been a continuously high demand from parents for earlier assessment and training for children suspected to have ASD. This model had not received extra funding for this integrated program for research, teaching and training in autism. We had to apply for various donations and grants to support the development of this pioneer program. The research output and organization of forums for public education and awareness are reviewed. The latter part of the paper reports the summary of clinical profile of autism cases (N=1441) assessed from 1985 to 2010 June under the University of Hong Kong. As the waiting time for initial developmental assessment for any children in Hong Kong is 12-24 months, we also report our preliminary experience with a newly launched triaging service provision for children suspected to be ASD since 2009, including multi-disciplinary assessment and parallel interim training in our university affiliated child assessment centre in Hong (N=89).
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Affiliation(s)
- Virginia Chun-Nei Wong
- Department of Paediatrics and Adolescent Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
| | - Cheuk-Wing Fung
- Department of Paediatrics and Adolescent Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - So-Lun Lee
- Department of Paediatrics and Adolescent Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - Polly Tsz Yan Wong
- Department of Paediatrics and Adolescent Medicine, the University of Hong Kong, Queen Mary Hospital, Hong Kong, China
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17
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Gipson TT, Gerner G, Srivastava S, Poretti A, Vaurio R, Hartman A, Johnston MV. Early neurodevelopmental screening in tuberous sclerosis complex: a potential window of opportunity. Pediatr Neurol 2014; 51:398-402. [PMID: 25160545 PMCID: PMC4196722 DOI: 10.1016/j.pediatrneurol.2014.04.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/29/2014] [Accepted: 04/30/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Infants born with tuberous sclerosis complex, a genetic condition resulting from a mutation in TSC1 or TSC2, are at increased risk for intellectual disability and/or autism. Features of epilepsy, neuropathology, genetics, as well as timing and type of mechanism-based medications have been proposed as risk factors. Neurodevelopmental outcomes have been reported among these studies; however, few include data about the individuals' early neurodevelopmental profile, a factor that may contribute significantly to these outcomes. Further, there is no clinical standard for the neurodevelopmental assessment of these infants. The paucity of data regarding the natural history of neurodevelopment in infants with tuberous sclerosis complex and the lack of a gold standard for neurodevelopmental evaluation present a significant challenge for clinicians and researchers. METHOD During the first year of life, we tracked the onset of infantile spasms, the type and timing of antiepileptic treatments, and the associated response of two age-matched infants with tuberous sclerosis complex. We also employed Capute Scales as a part of a structured neurodevelopmental evaluation to characterize and compare their neurodevelopmental profiles. RESULTS Infant 1 developed infantile spasms with confirmed hypsarrhythmia at 4 months of age. Treatment with vigabatrin was initiated within 24 hours with near immediate cessation of seizures and no further seizures to date. Expressive language delay was detected at 12 months and treated with speech and/or language therapy. Infant 2 developed complex partial seizures at 1 month. Treatment included levetiracetam, oxcarbazepine, and the ketogenic diet. Vigabatrin was initiated on detection of hypsarrhythmia after 4 months. Intractable epilepsy persists to date. Global developmental delay was evident by 8 months and treated with physical, occupational, and speech and/or language therapy. CONCLUSION Many risk factors have been associated with intellectual disability and/or autism in individuals with tuberous sclerosis complex; however, few data are available regarding practical clinical tools for early identification. In our case series, inclusion of the Capute Scales as a part of routine medical care led to the identification of developmental delays in the first 12 months of life and selection of targeted neurodevelopmental interventions. Development of a risk-based assessment using this approach will be the focus of future studies as it may provide a potential window of opportunity for both research and clinical purposes. In research, it may serve as an objective outcome measure. Clinically, this type of assessment has potential for informing clinical treatment decisions and serving as a prognostic indicator of long-term cognitive and psychiatric outcomes.
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Affiliation(s)
- Tanjala T. Gipson
- Tuberous Sclerosis Clinic, Kennedy Krieger Institute, Baltimore, MD,Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD,Clinical Trials Unit, Hugo W. Moser Research Institute, Inc., Kennedy Krieger Institute, Baltimore, MD,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Gwendolyn Gerner
- Tuberous Sclerosis Clinic, Kennedy Krieger Institute, Baltimore, MD,Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD,Clinical Trials Unit, Hugo W. Moser Research Institute, Inc., Kennedy Krieger Institute, Baltimore, MD
| | - Siddharth Srivastava
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD
| | - Andrea Poretti
- Section of Pediatric Neuroradiology, Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Rebecca Vaurio
- Department of Neuropsychology, Kennedy Krieger Institute, Baltimore, MD,Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Adam Hartman
- The John M. Freeman Pediatric Epilepsy Center, Department of Neurology, Johns Hopkins University School of Medicine
| | - Michael V. Johnston
- Tuberous Sclerosis Clinic, Kennedy Krieger Institute, Baltimore, MD,Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD,Clinical Trials Unit, Hugo W. Moser Research Institute, Inc., Kennedy Krieger Institute, Baltimore, MD,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD,Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD
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18
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Peters JM, Taquet M, Prohl AK, Scherrer B, van Eeghen AM, Prabhu SP, Sahin M, Warfield SK. Diffusion tensor imaging and related techniques in tuberous sclerosis complex: review and future directions. FUTURE NEUROLOGY 2013; 8:583-597. [PMID: 24489482 DOI: 10.2217/fnl.13.37] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this article, the authors aim to introduce the nonradiologist to diffusion tensor imaging (DTI) and its applications to both clinical and research aspects of tuberous sclerosis complex. Tuberous sclerosis complex is a genetic neurocutaneous syndrome with variable and unpredictable neurological comorbidity that includes refractory epilepsy, intellectual disability, behavioral abnormalities and autism spectrum disorder. DTI is a method for modeling water diffusion in tissue and can noninvasively characterize microstructural properties of the brain. In tuberous sclerosis complex, DTI measures reflect well-known pathological changes. Clinically, DTI can assist with detecting the epileptogenic tuber. For research, DTI has a putative role in identifying potential disease biomarkers, as DTI abnormalities of the white matter are associated with neurocognitive morbidity including autism. If indeed DTI changes parallel phenotypical changes related to the investigational treatment of epilepsy, cognition and behavior with mTOR inhibitors, it will facilitate future clinical trials.
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Affiliation(s)
- Jurriaan M Peters
- Department of Neurology & the Division of Epilepsy & Clinical Neurophysiology, Boston Children's Hospital, 300 Longwood Avenue, Fegan 9, Boston, MA 02115, USA ; Department of Radiology & the Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA 02115, USA
| | - Maxime Taquet
- Department of Radiology & the Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA 02115, USA ; ICTEAM Institute, Université catholique de Louvain, Place du Levant 2 bte L5.04.04, 1348 Louvain-La-Neuve, Belgium
| | - Anna K Prohl
- Department of Neurology & the Division of Epilepsy & Clinical Neurophysiology, Boston Children's Hospital, 300 Longwood Avenue, Fegan 9, Boston, MA 02115, USA ; Department of Radiology & the Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA 02115, USA
| | - Benoit Scherrer
- Department of Radiology & the Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA 02115, USA
| | - Agnies M van Eeghen
- Department of Neuroscience, ENCORE, Expertise Centre for Neurodevelopmental Disorders, Erasmus Medical Centre, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Sanjay P Prabhu
- Department of Radiology & the Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA 02115, USA
| | - Mustafa Sahin
- Department of Neurology & the Division of Epilepsy & Clinical Neurophysiology, Boston Children's Hospital, 300 Longwood Avenue, Fegan 9, Boston, MA 02115, USA
| | - Simon K Warfield
- Department of Radiology & the Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA 02115, USA
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19
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Temporal and mosaic Tsc1 deletion in the developing thalamus disrupts thalamocortical circuitry, neural function, and behavior. Neuron 2013; 78:895-909. [PMID: 23664552 DOI: 10.1016/j.neuron.2013.03.030] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2013] [Indexed: 11/23/2022]
Abstract
Tuberous sclerosis is a developmental genetic disorder caused by mutations in TSC1, which results in epilepsy, autism, and intellectual disability. The cause of these neurological deficits remains unresolved. Imaging studies suggest that the thalamus may be affected in tuberous sclerosis patients, but this has not been experimentally interrogated. We hypothesized that thalamic deletion of Tsc1 at distinct stages of mouse brain development would produce differential phenotypes. We show that mosaic Tsc1 deletion within thalamic precursors at embryonic day (E) 12.5 disrupts thalamic circuitry and alters neuronal physiology. Tsc1 deletion at this early stage is unique in causing both seizures and compulsive grooming in adult mice. In contrast, only a subset of these phenotypes occurs when thalamic Tsc1 is deleted at a later embryonic stage. Our findings demonstrate that abnormalities in a discrete population of neurons can cause global brain dysfunction and that phenotype severity depends on developmental timing and degree of genetic mosaicism.
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20
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van Eeghen AM, Terán LO, Johnson J, Pulsifer MB, Thiele EA, Caruso P. The neuroanatomical phenotype of tuberous sclerosis complex: focus on radial migration lines. Neuroradiology 2013; 55:1007-1014. [PMID: 23644537 DOI: 10.1007/s00234-013-1184-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 03/27/2013] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The contribution of radial migration lines (RMLs) to the neuroanatomical and neurocognitive phenotype of tuberous sclerosis complex (TSC) is unclear. The aim of this study was to perform a comprehensive evaluation of the neuroradiological phenotype of TSC, distinguishing RMLs from normal-appearing white matter (NAWM) using diffusion tensor imaging (DTI) and volumetric fluid-attenuated inversion recovery imaging. METHODS Magnetic resonance images of 30 patients with TSC were evaluated. The frequencies of RMLs, tubers, and subependymal nodules (SENs) were determined for every hemispheric lobe. Cerebellar lesions and subependymal giant cell tumors were counted. DTI metrics were obtained from the NAWM of every hemispheric lobe and from the largest RML and tuber. Analyses of variance and correlations were performed to investigate the associations between neuroanatomical characteristics and relationships between RML frequency and neurocognitive outcomes. NAWM DTI metrics were compared with measurements of 16 control patients. RESULTS A mean of 47 RMLs, 27 tubers, and 10 SENs were found per patient, and the frequencies of these lesions were strongly correlated (p < 0.001). RML fractional anisotropy and mean diffusivity were strongly inversely correlated (p = 0.003). NAWM DTI metrics were similar to the controls (p = 0.26). RML frequency was strongly associated with age of seizure onset (p = 0.003), intelligence outcomes (p = 0.01), and level of autistic features (p = 0.007). CONCLUSION A detailed neuroradiological phenotype is presented, showing that RMLs are the most frequent neuroanatomical lesion, are responsible for white matter DTI abnormalities, and are strongly associated with age of seizure onset, intelligence outcomes, and level of autistic features.
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Affiliation(s)
- Agnies M van Eeghen
- Department of Neurology, Carol and James Herscot Center for Tuberous Sclerosis Complex, Massachusetts General Hospital, 175 Cambridge Street, Boston, MA, 02114, USA.
- ENCORE, Expertise Centre for Neurodevelopmental Disorders, Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands.
| | - Laura Ortiz Terán
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Jason Johnson
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
| | - Margaret B Pulsifer
- Department of Psychiatry, Psychological Assessment Center, Massachusetts General Hospital, Boston, MA, USA
| | - Elizabeth A Thiele
- Department of Neurology, Carol and James Herscot Center for Tuberous Sclerosis Complex, Massachusetts General Hospital, 175 Cambridge Street, Boston, MA, 02114, USA
| | - Paul Caruso
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
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21
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Ehninger D. From genes to cognition in tuberous sclerosis: Implications for mTOR inhibitor-based treatment approaches. Neuropharmacology 2013; 68:97-105. [DOI: 10.1016/j.neuropharm.2012.05.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/03/2012] [Accepted: 05/13/2012] [Indexed: 01/27/2023]
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22
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Semi-automatic volumetry of cortical tubers in tuberous sclerosis complex. Jpn J Radiol 2013; 31:253-61. [DOI: 10.1007/s11604-012-0178-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 12/25/2012] [Indexed: 10/27/2022]
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Lewis WW, Sahin M, Scherrer B, Peters JM, Suarez RO, Vogel-Farley VK, Jeste SS, Gregas MC, Prabhu SP, Nelson CA, Warfield SK. Impaired language pathways in tuberous sclerosis complex patients with autism spectrum disorders. Cereb Cortex 2012; 23:1526-32. [PMID: 22661408 DOI: 10.1093/cercor/bhs135] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The purpose of this study was to examine the relationship between language pathways and autism spectrum disorders (ASDs) in patients with tuberous sclerosis complex (TSC). An advanced diffusion-weighted magnetic resonance imaging (MRI) was performed on 42 patients with TSC and 42 age-matched controls. Using a validated automatic method, white matter language pathways were identified and microstructural characteristics were extracted, including fractional anisotropy (FA) and mean diffusivity (MD). Among 42 patients with TSC, 12 had ASD (29%). After controlling for age, TSC patients without ASD had a lower FA than controls in the arcuate fasciculus (AF); TSC patients with ASD had even a smaller FA, lower than the FA for those without ASD. Similarly, TSC patients without ASD had a greater MD than controls in the AF; TSC patients with ASD had even a higher MD, greater than the MD in those without ASD. It remains unclear why some patients with TSC develop ASD, while others have better language and socio-behavioral outcomes. Our results suggest that language pathway microstructure may serve as a marker of the risk of ASD in TSC patients. Impaired microstructure in language pathways of TSC patients may indicate the development of ASD, although prospective studies of language pathway development and ASD diagnosis in TSC remain essential.
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Affiliation(s)
- William W Lewis
- Department of Neurology, Children’s Hospital Boston and Harvard Medical School, Boston, MA 02115, USA
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Marcotte L, Aronica E, Baybis M, Crino PB. Cytoarchitectural alterations are widespread in cerebral cortex in tuberous sclerosis complex. Acta Neuropathol 2012; 123:685-93. [PMID: 22327361 DOI: 10.1007/s00401-012-0950-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 01/22/2012] [Accepted: 01/26/2012] [Indexed: 11/28/2022]
Abstract
Tubers are cerebral cortical developmental malformations associated with epilepsy and autism in tuberous sclerosis complex (TSC). The disparity between tuber number and severity of neurological impairment often observed in TSC led us to hypothesize that microscopic structural abnormalities distinct from tubers may occur in TSC. Serial frontal to occipital lobe sections were prepared from five postmortem TSC brain specimens. Sections were probed with cresyl violet stain or NeuN antibodies to define cytoarchitectural abnormalities and phospho-S6 (Ser235/236) antibodies to define mammalian target of rapamycin complex 1 (mTORC1) pathway activation. Tubers identified in all specimens (mean, 5 tubers per brain specimen) were defined by abnormal cortical lamination, dysmorphic neurons, and giant cells (GCs) and exhibited robust phospho-S6 immunolabeling. Histopathological analysis of non-tuber cortices demonstrated that 32% of the sections exhibited microscopic cytoarchitectural alterations, whereas 68% of the sections did not. Four types of morphological abnormalities were defined including: (1) focal dyslamination, (2) heterotopic neurons, (3) small collections of giant cells (GCs) and neurons we termed "microtubers", (4) isolated GCs we termed "sentinel" cells. When compared with control cortex, phospho-S6 labeling was enhanced in microtubers and sentinel cells and in some but not all areas of dyslamination. There are microscopic cytoarchitectural abnormalities identified in postmortem TSC brain specimens that are distinct from tubers. mTORC1 cascade activation in these areas supports a widespread effect of TSC1 or TSC2 mutations on brain development. Tubers may represent the most dramatic developmental abnormality in TSC; however, more regionally pervasive yet subtle abnormalities may contribute to neurological disability in TSC.
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Affiliation(s)
- Leah Marcotte
- Department of Neurology, PENN Epilepsy Center, University of Pennsylvania Medical Center, Philadelphia, 19104, USA
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Gomes WA, Shinnar S. Prospects for imaging-related biomarkers of human epileptogenesis: a critical review. Biomark Med 2012; 5:599-606. [PMID: 22003908 DOI: 10.2217/bmm.11.66] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
To facilitate the study of epileptogenesis in humans, noninvasive biomarkers of epileptogenesis are required. No validated biomarker is currently available, but brain imaging techniques provide many attractive candidates. In this article we examine the imaging features of temporal lobe epilepsy, focusing on those that may precede the onset of epilepsy and correlate with epileptogenesis. Hippocampal volumetry and T(2) relaxometry are proposed as candidate biomarkers of epileptogenesis in temporal lobe epilepsy following febrile status epilepticus. Preliminary data suggest that these have promise, and the ongoing Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study will provide more conclusive evidence as to their validity. At this time there are no other clear candidates for imaging-related biomarkers of epileptogenesis in human studies.
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Affiliation(s)
- William A Gomes
- Comprehensive Epilepsy Management Center, Montefiore Medical Center, 111 E. 210th St, Bronx, NY 10467, USA
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Ameis SH, Szatmari P. Imaging-genetics in autism spectrum disorder: advances, translational impact, and future directions. Front Psychiatry 2012; 3:46. [PMID: 22615702 PMCID: PMC3351673 DOI: 10.3389/fpsyt.2012.00046] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/23/2012] [Indexed: 12/29/2022] Open
Abstract
Autism Spectrum Disorder (ASD) refers to a group of heterogeneous neurodevelopmental disorders that are unified by impairments in reciprocal social communication and a pattern of inflexible behaviors. Recent genetic advances have resolved some of the complexity of the genetic architecture underlying ASD by identifying several genetic variants that contribute to the disorder. Different etiological pathways associated with ASD may converge through effects on common molecular mechanisms, such as synaptogenesis, neuronal motility, and axonal guidance. Recently, with more sophisticated techniques, neuroimaging, and neuropathological studies have provided some consistency of evidence that altered structure, activity, and connectivity within complex neural networks is present in ASD, compared to typically developing children. The imaging-genetics approach promises to help bridge the gap between genetic variation, resultant biological effects on the brain, and production of complex neuropsychiatric symptoms. Here, we review recent findings from the developing field of imaging-genetics applied to ASD. Studies to date have indicated that relevant risk genes are associated with alterations in circuits that mediate socio-emotional, visuo-spatial, and language processing. Longitudinal studies ideally focused on early development, in conjunction with investigation for gene-gene, and gene-environment interactions may move the promise of imaging-genetics in ASD closer to the clinical domain.
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Affiliation(s)
- Stephanie H Ameis
- Department of Psychiatry, The Hospital for Sick Children, University of Toronto Toronto, ON, Canada
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Numis AL, Major P, Montenegro MA, Muzykewicz DA, Pulsifer MB, Thiele EA. Identification of risk factors for autism spectrum disorders in tuberous sclerosis complex. Neurology 2011; 76:981-7. [PMID: 21403110 DOI: 10.1212/wnl.0b013e3182104347] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE The purpose of this study was to assess the prevalence of and to identify epidemiologic, genetic, electrophysiologic, and neuroanatomic risk factors for autism spectrum disorders (ASD) in a cohort of patients with tuberous sclerosis complex (TSC). METHODS A total of 103 patients with TSC were evaluated for ASD. A retrospective review of patients' records was performed, including mutational analysis. EEG reports were analyzed for the presence of ictal and interictal epileptiform features. Brain MRI scans were evaluated for TSC neuropathology, including tuber burden. RESULTS Of the 103 patients with TSC, 40%were diagnosed with an ASD. On univariate analysis, patients with ASD were less likely to have mutations in the TSC1 gene. Patients with ASD also had an earlier age at seizure onset and more frequent seizures. On EEG, those with ASD had a significantly greater amount of interictal epileptiform features in the left temporal lobe only. On MRI, there were no differences in the regional distribution of tuber burden, although those with TSC2 and ASD had a higher prevalence of cyst-like tubers. CONCLUSIONS The development of ASD in TSC is not well understood. Given our findings, ASD may be associated with persistent seizure activity early in development in particular brain regions, such as those responsible for social perception and communication in the left temporal lobe. The presence of cyst-like tubers on MRI could provide a structural basis or marker for ASD pathology in TSC, although studies assessing their effect on cortical function are needed.
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Affiliation(s)
- A L Numis
- Department of Neurology, Massachusetts General Hospital, Boston, USA
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Kassiri J, Snyder TJ, Bhargava R, Wheatley BM, Sinclair DB. Cortical tubers, cognition, and epilepsy in tuberous sclerosis. Pediatr Neurol 2011; 44:328-32. [PMID: 21481739 DOI: 10.1016/j.pediatrneurol.2011.01.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 12/20/2010] [Indexed: 11/28/2022]
Abstract
Tuberous sclerosis complex is an autosomal-dominant genetic disorder characterized by hamartomatous growth in various organs. Patients who have this disorder exhibit a high rate of epilepsy and cognitive problems. We investigated number of tubers, location, seizure types, and cognitive outcome, and we analyzed the relationships among them in our tuberous sclerosis patients in the Comprehensive Epilepsy Program at the University of Alberta. We also examined the seizure outcome after tuber resection. Our study cohort included 24 patients with tuberous sclerosis complex. We obtained seizure history, electroencephalogram, and neuropsychologic parameters. Magnetic resonance imaging was used to examine tuber numbers and locations. Ten patients underwent surgical removal of tubers responsible for intractable epilepsy. A negative correlation was found between the number of tubers and intelligent quotient score. Epilepsy surgery led to freedom from seizures in this patient group. We demonstrated that the total number and location of cortical tubers play a significant role in the extent of mental retardation in patients with tuberous sclerosis complex. In addition, patients with intractable seizures and well-defined epileptic focus had excellent surgical outcome.
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Affiliation(s)
- Janani Kassiri
- Comprehensive Epilepsy Program, University of Alberta Hospital, Edmonton, Alberta, Canada
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Kaczorowska M, Jurkiewicz E, Domańska-Pakieła D, Syczewska M, Lojszczyk B, Chmielewski D, Kotulska K, Kuczyński D, Kmieć T, Dunin-Wąsowicz D, Kasprzyk-Obara J, Jóźwiak S. Cerebral tuber count and its impact on mental outcome of patients with tuberous sclerosis complex. Epilepsia 2011; 52:22-7. [PMID: 21204819 DOI: 10.1111/j.1528-1167.2010.02892.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE The aim of the study was to reveal the relationships between the tuber count of the brain found in patients with tuberous sclerosis complex (TSC) and their cognitive outcome. METHODS A single-center, retrospective analysis was performed of patients with documented TSC seen from 1988 to 2010 at the Children's Memorial Health Institute, Warsaw, Poland. KEY FINDINGS Sixty-two patients were analyzed, and there was a significant correlation between younger age at the first seizure and developmental delay. The patients who did not develop seizures had normal development, despite some presenting with higher tuber load than those with seizures. There was a statistically significant negative correlation between the number of tubers within the right temporal lobe and cognition. SIGNIFICANCE Our findings confirm our hypothesis that the cognitive outcome in TSC is more dependent on the age of the seizure onset rather than on the tuber count.
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Affiliation(s)
- Magdalena Kaczorowska
- Department of Neurology Radiology, MR Unit Pediatric Rehabilitation Psychology, The Children's Memorial Health Institute, Warsaw, Poland
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Tsc2-Rheb signaling regulates EphA-mediated axon guidance. Nat Neurosci 2010; 13:163-72. [PMID: 20062052 PMCID: PMC2812631 DOI: 10.1038/nn.2477] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Accepted: 11/24/2009] [Indexed: 12/11/2022]
Abstract
Tuberous sclerosis complex is a disease caused by mutations in the TSC1 or TSC2 genes, which encode a protein complex that inhibits mTOR kinase signaling by inactivating the Rheb GTPase. Activation of mTOR promotes the formation of benign tumors in various organs while the mechanisms underlying the neurological symptoms of the disease remain largely unknown. Here, we report that in mice Tsc2 haploinsufficiency causes aberrant retinogeniculate projections that suggest defects in EphA receptor-dependent axon guidance. We also show that EphA receptor activation by ephrin-A ligands in neurons leads to inhibition of ERK1/2 kinase activity and decreased inhibition of Tsc2 by ERK1/2. Thus, ephrin stimulation inactivates the mTOR pathway by enhancing Tsc2 activity. Furthermore, Tsc2 deficiency and hyperactive Rheb constitutively activate mTOR and inhibit ephrin-induced growth cone collapse. Our results demonstrate that TSC2-Rheb-mTOR signaling cooperates with the ephrin-Eph receptor system to control axon guidance in the visual system.
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Ehninger D, de Vries PJ, Silva AJ. From mTOR to cognition: molecular and cellular mechanisms of cognitive impairments in tuberous sclerosis. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2009; 53:838-51. [PMID: 19694899 PMCID: PMC2844770 DOI: 10.1111/j.1365-2788.2009.01208.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
BACKGROUND Tuberous sclerosis (TSC) is a multi-system disorder caused by heterozygous mutations in the TSC1 or TSC2 gene and is often associated with neuropsychiatric symptoms, including intellectual disability, specific neuropsychological deficits, autism, other behavioural disorders and epilepsy. METHOD Here, we review evidence from animal models of TSC for the role of specific molecular and cellular processes in the pathogenesis of cognitive, developmental and epilepsy-related manifestations seen in the disorder. RESULTS Recent evidence shows that, in animal models, disinhibited mTOR (mammalian target of rapamycin) signalling substantially contributes to neuropsychiatric phenotypes, including cognitive deficits and seizures. We discuss potential pathogenetic mechanisms involved in the cognitive phenotypes of TSC and present implications regarding mTOR inhibitor-based treatments for TSC-related neuropsychiatric features. CONCLUSIONS Results suggest that reversing the underlying molecular deficits of TSC with rapamycin or other mTOR inhibitors could result in clinically significant improvements of cognitive function and neurological symptoms, even if treatments are started in adulthood.
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Affiliation(s)
- D Ehninger
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, Psychology and the Brain Research Institute, UCLA, Los Angeles, CA 90095-1761, USA.
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Abstract
Tuberous Sclerosis Complex (TSC) is a multiorgan genetic disease caused by loss of function of either the TSC1 (encodes hamartin) or TSC2 (encodes tuberin) genes. Patients with TSC have benign tumors (hamartomas) in multiple organs though brain involvement is typically the most disabling aspect of the disease as very high rates of neurodevelopmental disorders are seen. While first described well over 120 years ago, recent advances have transformed TSC into a prototypical disorder that exemplifies the methods and potential of molecular medicine. This review will detail historical aspects of TSC and its strong associations with neurodevelopmental disorders focusing on epilepsy and autism. Finally, promising new approaches for the treatment of epilepsy and autism in patients with TSC as well as those in the general population will be discussed.
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Affiliation(s)
- Kevin C Ess
- Department of Neurology, Vanderbilt Kennedy Center for Research on Human Development, Tuberous Sclerosis Clinic, Vanderbilt Children's' Hospital, Vanderbilt University, 2201 West End Avenue, Nashville, TN, 37240, USA,
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Kaufmann R, Kornreich L, Goldberg-Stern H. Unusual clinical presentation of tuberless tuberous sclerosis complex. J Child Neurol 2009; 24:361-4. [PMID: 19258298 DOI: 10.1177/0883073808325659] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cortical tubers are the hallmark of tuberous sclerosis. Their presence is expected on brain imaging, especially when seizures begin before 1 year of age with concomitant significant developmental delay. Increased tuber counts have been reported to be associated with seizures and poor cognitive outcome. We present a 3-year-old girl with intractable seizures that started as infantile spasms at 2 months of age and who was diagnosed with clinically definitive tuberous sclerosis. Poor prognostic signs included multiple seizure types, seizure onset before 1 year of age, and multifocal electroencephalographic abnormalities. However, on repeated brain magnetic resonance imaging scans, the known radiological findings associated with tuberous sclerosis complex were absent, raising a diagnostic dilemma. Therefore, genetic analysis was performed. A mutation was detected in the TSC2 gene, confirming the diagnosis. To the best of our knowledge, this is the first reported case of tuberless tuberous sclerosis complex associated with intractable epilepsy and developmental delay.
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Affiliation(s)
- Rami Kaufmann
- Department of Child Neurology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel
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Pollock JM, Whitlow CT, Tan H, Kraft RA, Burdette JH, Maldjian JA. Pulsed arterial spin-labeled MR imaging evaluation of tuberous sclerosis. AJNR Am J Neuroradiol 2009; 30:815-20. [PMID: 19147711 DOI: 10.3174/ajnr.a1428] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Tuberous sclerosis presents with characteristic cortical hamartomas and subependymal nodules associated with seizures. The purpose of this study was to use pulsed arterial spin-labeling (PASL) to quantify the perfusion of the cortical hamartomas and correlate the perfusion values with seizure frequency. MATERIALS AND METHODS A retrospective search yielded 16 MR imaging examinations including conventional MR imaging and PASL perfusion performed in 13 patients (age range, 7 months to 23 years) with a history of tuberous sclerosis. The mean perfusion of each cortical hamartoma greater than 5 mm in size localized with conventional MR imaging sequences was obtained with use of manually drawn regions of interest. Cortical hamartomas were classified as normal, hyperperfused, or hypoperfused on the basis of the mean and SD of the unaffected cortex. Correlation was made between perfusion imaging, conventional imaging, and clinical history. RESULTS Of the 245 cortical hamartomas, 227 (92.7%) were hypoperfused, 10 (4.1%) were hyperperfused, and 8 (3.3%) were unchanged relative to the mean gray matter. One patient had a subependymal giant cell astrocytoma with a mean perfusion of 93.5 mL/100 g tissue/min. There was a statistically significant positive correlation between seizure frequency and the number of hyperperfused cortical tubers (r = 0.51; n = 16; P = .04), with higher seizure frequency associated with a greater number of hyperperfused cortical tubers. There was no significant correlation, however, between seizure frequency and the overall number of cortical tubers (r = 0.20; n = 16; P = .47). CONCLUSIONS The PASL technique can assess and quantify the perfusion characteristics of a cortical hamartoma. Most lesions are hypoperfused; however, both normally perfused and hyperperfused lesions occur. The presence of hyperperfused cortical tubers was associated with increased seizure frequency.
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Affiliation(s)
- J M Pollock
- Department of Radiology, Wake Forest University, Winston-Salem, NC, USA.
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Self-injurious behavior and tuberous sclerosis complex: frequency and possible associations in a population of 257 patients. Epilepsy Behav 2008; 13:650-3. [PMID: 18703161 DOI: 10.1016/j.yebeh.2008.07.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 07/21/2008] [Accepted: 07/26/2008] [Indexed: 12/14/2022]
Abstract
Self-injurious behavior (SIB) has been observed in people with tuberous sclerosis complex (TSC), although the frequency of SIB in TSC is largely unknown. SIB is associated with intellectual and developmental disabilities, but there is no single cause of SIB. We retrospectively examined the frequency of SIB in a population of 257 patients with TSC and determined possible associations with SIB. We found a 10% frequency of SIB in our TSC population. When compared with patients without psychiatric symptoms, we identified a significantly higher rate of electroencephalographic interictal spikes in the left frontal lobe and a significantly lower number of tubers in the left occipital, parietal, and posterior temporal lobes. We also found that frequency of TSC2 mutation, history of infantile spasms, history of seizures, mental retardation, and autism are significantly associated with SIB.
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Goorden SMI, van Woerden GM, van der Weerd L, Cheadle JP, Elgersma Y. Cognitive deficits in Tsc1+/- mice in the absence of cerebral lesions and seizures. Ann Neurol 2008; 62:648-55. [PMID: 18067135 DOI: 10.1002/ana.21317] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE Tuberous sclerosis complex (TSC) is characterized by brain lesions, epilepsy, increased incidence of mental retardation and autism. The causal link between lesion load and epilepsy on cognitive disabilities has been debated, and these factors explain only part of the intelligence quotient variability. A Tsc2 rat model of the disease provided evidence that the TSC genes are directly involved in neuronal function. However, these lesion- and epilepsy-free animals did not show learning deficits, leaving open the possibility that the presence of brain lesions or epilepsy is a prerequisite for the cognitive deficits to fully develop. Here, we reinvestigated the relation among cerebral lesions, epilepsy, and cognitive function using Tsc1+/- mice. METHODS We used immunocytochemistry and high-resolution magnetic resonance imaging to study the presence of neuronal pathology in Tsc1+/- mice. We used the Morris water maze, fear conditioning, social interaction, and nest building test to study the presence of cognitive and social deficits. RESULTS We observed no spontaneous seizures or cerebral lesions in the brains of Tsc1+/- mice. In addition, giant dysmorphic cells were absent, and spine number and dendritic branching appeared to be normal. Nevertheless, Tsc1+/- mice showed impaired learning in the hippocampus-sensitive versions of the learning tasks and impaired social behavior. INTERPRETATION Tsc1+/- mice show social and cognitive deficits in the absence of apparent cerebral pathology and spontaneous seizures. These findings support a model in which haploinsufficiency for the TSC genes leads to aberrations in neuronal functioning resulting in impaired learning and social behavior.
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Affiliation(s)
- Susanna M I Goorden
- Department of Neuroscience, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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Raznahan A, Higgins NP, Griffiths PD, Humphrey A, Yates JRW, Bolton PF. Biological markers of intellectual disability in tuberous sclerosis. Psychol Med 2007; 37:1293-1304. [PMID: 17335641 DOI: 10.1017/s0033291707000177] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Intellectual disability (ID) is highly prevalent in tuberous sclerosis (TS). Putative neurobiological risk factors include indices of cortical tuber (CT) load and epilepsy. We have used univariate and multivariate analyses, including both CT and epilepsy measures as predictors, in an attempt to clarify the pattern of cross-sectional associations between these variables and ID in TS. METHOD Forty-eight children, adolescents and young adults with TS were identified through regional specialist clinics. All subjects underwent thorough history taking and examination, and had brain magnetic resonance imaging (MRI) scans. The number and regional distribution of CTs was recorded. Subjects were assigned to one of nine ordered intellectual quotient (IQ) categories (range 130) using age-appropriate tests of intelligence. RESULTS On univariate analyses, ID was significantly associated with both a history of infantile spasm (IS) (Z=-2.49, p=0.01) and total CT count (Spearman's rho=-0.30, p=0.04). When controlling for total CT count, the presence of CTs in frontal (regression coefficient=-2.43, p=0.02) and temporal (regression coefficient=-1.60, p=0.02) lobes was significantly associated with ID. In multivariate analyses the association between IS and ID was rendered insignificant by the inclusion of the presence of CTs in temporal and frontal lobes, both of which remained associated (p=0.05 and p=0.06 respectively) with ID. CONCLUSIONS The presence of CTs in specific brain regions as opposed to a history of IS was associated with ID in TS. The significance of these findings is discussed in relation to previous work in TS, and the neural basis of intelligence.
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Affiliation(s)
- Armin Raznahan
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, King's College London, UK.
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de Vries PJ, Howe CJ. The tuberous sclerosis complex proteins – a GRIPP on cognition and neurodevelopment. Trends Mol Med 2007; 13:319-26. [PMID: 17632034 DOI: 10.1016/j.molmed.2007.06.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2007] [Revised: 06/06/2007] [Accepted: 06/18/2007] [Indexed: 10/23/2022]
Abstract
Tuberous sclerosis complex (TSC) is a multi-system disorder associated with mutations in the TSC1 (hamartin) or TSC2 (tuberin) genes. The neurocognitive features of TSC show wide variability and have generally been attributed to structural brain abnormalities and/or seizures. We review the fundamental roles of TSC1 and TSC2 in cell signalling and propose that because the hamartin-tuberin complex (hereafter referred to as TSC1-2) acts as a global regulator and integrator of a range of physiological processes ('GRIPP') the neurocognitive manifestations of TSC result directly from cell-signalling abnormalities. Under the GRIPP hypothesis, the spectrum of neurodevelopmental abnormalities is caused by the biochemical consequences of individual TSC1 and TSC2 mutations. Recognizing the importance of signalling disruption in the brain might improve our understanding of other neurocognitive disorders.
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Affiliation(s)
- Petrus J de Vries
- Developmental Psychiatry Section, University of Cambridge, Douglas House, 18b Trumpington Road, Cambridge, CB2 2AH, UK.
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Abstract
There has been increasing awareness that there are behavioral phenotypes in tuberous sclerosis complex with neuropsychiatric symptom complex such as autistic disorder and attention-deficit hyperactivity disorder (ADHD). However, the neurobiologic basis of autistic disorder in tuberous sclerosis complex is still unknown. We studied two cohorts of children followed up since 1986 until 2003, one cohort with tuberous sclerosis complex and another cohort with autistic disorder, to determine the incidence of autistic disorder in tuberous sclerosis complex and the incidence of tuberous sclerosis complex in autistic disorder respectively. We established a Tuberous Sclerosis Complex Registry in 1985 at the University of Hong Kong. In 2004, 44 index cases (the male to female ratio was 0.75:1) were registered. Three had a positive family history of tuberous sclerosis complex. Thus, the total number of tuberous sclerosis complex cases was 47. We adopted the diagnostic criteria of tuberous sclerosis complex for case ascertainment. The period prevalence rate of tuberous sclerosis complex for children and adolescents aged < 20 years is 3.5 per 10,000 (on Hong Kong island, excluding the eastern region with 125,100 aged < 20 years in 2003). Of 44 cases with tuberous sclerosis complex, 7 had autistic disorder. Thus, the incidence of autistic disorder in tuberous sclerosis complex is 16%. During the 17-year period (1986-2003), we collected a database of 753 children (668 boys and 84 girls; male to female ratio 8:1) with autistic disorder and pervasive developmental disorders. For all children with autistic disorder or pervasive developmental disorders, we routinely examined for any features of tuberous sclerosis complex by looking for neurocutaneous markers such as depigmented spots, which appear in 50% of children with tuberous sclerosis complex by the age of 2 years. For those with infantile spasm or epilepsy, the clinical features of tuberous sclerosis complex were monitored regularly during follow-up. Of these, seven had tuberous sclerosis complex. Thus, the incidence of tuberous sclerosis complex in autistic disorder is 0.9%. All of these children are mentally retarded, with moderate to severe grades in an intellectual assessment conducted by a clinical psychologist. Future studies should be directed toward looking at the various behavioral phenotypes in tuberous sclerosis complex and defining these with standardized criteria to look for any real association with the underlying genetic mutation of TSC1 or TSC2 gene or even the site of tubers in the brain.
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Affiliation(s)
- Virginia Wong
- Division of Neurodevelopmental Paediatrics, Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, China.
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