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Milon V, Malinge MC, Blanluet M, Tessarech M, Battault C, Prestwich S, Vary B, Gueracher P, Legoff L, Barth M, Houdayer C, Guichet A, Rousseau A, Bonneau D, Procaccio V, Bris C, Colin E. Diagnosis of tuberous sclerosis in the prenatal period: a retrospective study of 240 cases and review of the literature. Eur J Hum Genet 2024:10.1038/s41431-024-01631-w. [PMID: 38806662 DOI: 10.1038/s41431-024-01631-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 05/04/2024] [Accepted: 05/09/2024] [Indexed: 05/30/2024] Open
Abstract
Tuberous sclerosis complex (TSC) is a rare multisystemic disorder caused by a pathogenic variant in the TSC1 or TSC2 gene. A great phenotypic variability characterises TSC. The condition predisposes to the formation of hamartomas in various tissues, neurologic and neurodevelopmental disorders such as epilepsy, psychiatric disorders, as well as intellectual disability in 50%. TSC may be responsible for cardiac rhabdomyomas (CRs), cortical tubers, or subependymal nodules during foetal life. Detecting multiple CRs is associated with a very high risk of TSC, but the CR could be single and isolated. Few data exist to estimate the risk of TSC in these cases. We report the largest series of prenatal genetic tests for TSC with a retrospective study of 240 foetuses presenting with suggestive antenatal signs. We also provide a review of the literature to specify the probability of clinical or genetic diagnosis of TSC in case of detection of single or multiple CRs. Indeed, an early diagnosis is crucial for the counselling of the couple and their families. In this series, a definite diagnosis was assessed in 50% (41/82) of foetuses who initially presented with a single CR and 80.3% (127/158) in cases of multiple CRs. The prevalence of parental germinal mosaicism was 2.6% (3/115).
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Affiliation(s)
- Vincent Milon
- Genetics Department, Angers Hospital, F-49000, Angers, France.
| | | | - Maud Blanluet
- Genetics Department, Angers Hospital, F-49000, Angers, France
| | - Marine Tessarech
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | | | - Sarah Prestwich
- Genetics Department, Angers Hospital, F-49000, Angers, France
| | - Béatrice Vary
- Genetics Department, Angers Hospital, F-49000, Angers, France
| | | | - Louis Legoff
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | - Magalie Barth
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | - Clara Houdayer
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | - Agnès Guichet
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | - Audrey Rousseau
- Tissular and Cellular Pathology Department, Angers Hospital, F-49000, Angers, France
| | - Dominique Bonneau
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | - Vincent Procaccio
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | - Céline Bris
- Genetics Department, Angers Hospital, F-49000, Angers, France
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France
| | - Estelle Colin
- Genetics Department, Angers Hospital, F-49000, Angers, France.
- Univ Angers, [CHU Angers], Inserm, CNRS, MITOVASC, Équipe CARME ou Equipe MITOLAB, SFR ICAT, F-49000, Angers, France.
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Peterson M, Kolin DL, Konstantinopoulos PA. Case report: Response to everolimus in a patient with platinum resistant, high grade serous ovarian carcinoma with biallelic TSC2 inactivation. Front Oncol 2024; 14:1357980. [PMID: 38601768 PMCID: PMC11004469 DOI: 10.3389/fonc.2024.1357980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 03/15/2024] [Indexed: 04/12/2024] Open
Abstract
Background Patients with platinum-resistant recurrent high grade serous ovarian carcinoma have poor outcomes and limited treatment options. Case presentation We present a case of a 48-year-old woman with platinum-resistant high grade serous ovarian carcinoma harboring the pathogenic TSC2 R611Q variant with concomitant single copy loss of TSC2 (suggesting biallelic TSC2 inactivation) identified in targeted tumor sequencing. The patient was treated with the mTOR inhibitor everolimus, with an excellent response by imaging and a marked decrease in CA125; she remained on everolimus for 19 months until she developed progressive disease. Conclusions While mTOR inhibition is frequently used in tumors associated with tuberous sclerosis complex (TSC), such as lymphangioleiomyomatosis and malignant perivascular epithelioid cell tumors, this is the first case of a patient with ovarian cancer harboring TSC1/2 mutations who responded to mTOR inhibition. This case highlights the utility of targeted DNA sequencing in the management of ovarian carcinoma and demonstrates the value of tumor-agnostic targeted therapies.
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Affiliation(s)
- Mariko Peterson
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA, United States
| | - David L. Kolin
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA, United States
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Kleiblová P, Černá M, Zemánková P, Matějková K, Nehasil P, Hojný J, Horáčková K, Janatová M, Soukupová J, Šťastná B, Kleibl Z. Parallel DNA/RNA NGS Using an Identical Target Enrichment Panel in the Analysis of Hereditary Cancer Predisposition. Folia Biol (Praha) 2024; 70:62-73. [PMID: 38830124 DOI: 10.14712/fb2024070010062] [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] [Indexed: 06/05/2024]
Abstract
Germline DNA testing using the next-gene-ration sequencing (NGS) technology has become the analytical standard for the diagnostics of hereditary diseases, including cancer. Its increasing use places high demands on correct sample identification, independent confirmation of prioritized variants, and their functional and clinical interpretation. To streamline these processes, we introduced parallel DNA and RNA capture-based NGS using identical capture panel CZECANCA, which is routinely used for DNA analysis of hereditary cancer predisposition. Here, we present the analytical workflow for RNA sample processing and its analytical and diagnostic performance. Parallel DNA/RNA analysis allowed credible sample identification by calculating the kinship coefficient. The RNA capture-based approach enriched transcriptional targets for the majority of clinically relevant cancer predisposition genes to a degree that allowed analysis of the effect of identified DNA variants on mRNA processing. By comparing the panel and whole-exome RNA enrichment, we demonstrated that the tissue-specific gene expression pattern is independent of the capture panel. Moreover, technical replicates confirmed high reproducibility of the tested RNA analysis. We concluded that parallel DNA/RNA NGS using the identical gene panel is a robust and cost-effective diagnostic strategy. In our setting, it allows routine analysis of 48 DNA/RNA pairs using NextSeq 500/550 Mid Output Kit v2.5 (150 cycles) in a single run with sufficient coverage to analyse 226 cancer predisposition and candidate ge-nes. This approach can replace laborious Sanger confirmatory sequencing, increase testing turnaround, reduce analysis costs, and improve interpretation of the impact of variants by analysing their effect on mRNA processing.
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Affiliation(s)
- Petra Kleiblová
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
| | - Marta Černá
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Petra Zemánková
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
- Institute of Pathological Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Kateřina Matějková
- Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Petr Nehasil
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
- Institute of Pathological Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jan Hojný
- Institute of Pathology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Klára Horáčková
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Markéta Janatová
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Jana Soukupová
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Barbora Šťastná
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Zdeněk Kleibl
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
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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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Duan J, Ye Y, Hu Z, Zhao X, Liao J, Chen L. Identification of a Novel Canonical Splice Site Variant TSC2 c.2967-1G>T That is Not Associated With Tuberous Sclerosis Pathogenesis. Front Genet 2022; 13:904224. [PMID: 35692821 PMCID: PMC9184681 DOI: 10.3389/fgene.2022.904224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/16/2022] [Indexed: 11/27/2022] Open
Abstract
Tuberous sclerosis, also known as tuberous sclerosis complex (TSC), is an autosomal dominant defect characterized by hamartomas in multiple organ systems. Inactivating variants cause this defect in either the TSC1 gene or the TSC2 gene, leading to hamartin or tuberin protein dysfunction, thus resulting in TSC. The diagnostic criteria for TSC suggest that it can be diagnosed by identifying a heterozygous pathogenic variant of TSC1 or TSC2, even in the absence of clinical signs. In a 4-year-old girl, we identified a splicing variant (NM_000548.4: c.2967-1G>T) that she inherited from her father. Neither the girl (patient) nor her father showed typical features of TSC. This variant is located in a NAGNAG acceptor, which can produce mRNA isoforms that differ by a three-nucleotide indel. Reverse transcription polymerase chain reaction analysis of the patient and both parents' blood RNA samples suggested two different splicing patterns, and these two splicing patterns differed in the presence or absence of the first codon of exon 27, thus providing two splicing products designated as isoforms A and B, respectively. Furthermore, the proportions of these two patterns varied between the patient and either parent. A minigene assay further confirmed that the c.2967-1G>T variant led to the absence of isoform A (including the first codon of exon 27). The finding of our study demonstrates this variant, c.2967-1G>T, disrupts the balance of an alternative splice event which involves the use of two tandem alternatives acceptors and is not associated with typical symptoms of tuberous sclerosis. Our finding is of importance for genetic counseling and suggests that we need to be vigilant to avoid misdiagnosis when we encounter such a site.
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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: 4] [Impact Index Per Article: 1.0] [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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Rosengren T, Nanhoe S, de Almeida LGD, Schönewolf-Greulich B, Larsen LJ, Hey CAB, Dunø M, Ek J, Risom L, Nellist M, Møller LB. Mutational analysis of TSC1 and TSC2 in Danish patients with tuberous sclerosis complex. Sci Rep 2020; 10:9909. [PMID: 32555378 PMCID: PMC7303179 DOI: 10.1038/s41598-020-66588-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 05/19/2020] [Indexed: 02/07/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by hamartomas in the skin and other organs, including brain, heart, lung, kidney and bones. TSC is caused by mutations in TSC1 and TSC2. Here, we present the TSC1 and TSC2 variants identified in 168 Danish individuals out of a cohort of 327 individuals suspected of TSC. A total of 137 predicted pathogenic or likely pathogenic variants were identified: 33 different TSC1 variants in 42 patients, and 104 different TSC2 variants in 126 patients. In 40 cases (24%), the identified predicted pathogenic variant had not been described previously. In total, 33 novel variants in TSC2 and 7 novel variants in TSC1 were identified. To assist in the classification of 11 TSC2 variants, we investigated the effects of these variants in an in vitro functional assay. Based on the functional results, as well as population and genetic data, we classified 8 variants as likely to be pathogenic and 3 as likely to be benign.
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Affiliation(s)
- Thomas Rosengren
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Santoesha Nanhoe
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Luis Gustavo Dufner de Almeida
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Bitten Schönewolf-Greulich
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Lasse Jonsgaard Larsen
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Caroline Amalie Brunbjerg Hey
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Morten Dunø
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Jakob Ek
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Lotte Risom
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Lisbeth Birk Møller
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark.
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Dufner Almeida LG, Nanhoe S, Zonta A, Hosseinzadeh M, Kom-Gortat R, Elfferich P, Schaaf G, Kenter A, Kümmel D, Migone N, Povey S, Ekong R, Nellist M. Comparison of the functional and structural characteristics of rare TSC2 variants with clinical and genetic findings. Hum Mutat 2019; 41:759-773. [PMID: 31799751 PMCID: PMC7154745 DOI: 10.1002/humu.23963] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/31/2019] [Accepted: 11/27/2019] [Indexed: 01/09/2023]
Abstract
The TSC1 and TSC2 gene products interact to form the tuberous sclerosis complex (TSC), an important negative regulator of the mechanistic target of rapamycin complex 1 (TORC1). Inactivating mutations in TSC1 or TSC2 cause TSC, and the identification of a pathogenic TSC1 or TSC2 variant helps establish a diagnosis of TSC. However, it is not always clear whether TSC1 and TSC2 variants are inactivating. To determine whether TSC1 and TSC2 variants of uncertain clinical significance affect TSC complex function and cause TSC, in vitro assays of TORC1 activity can be employed. Here we combine genetic, functional, and structural approaches to try and classify a series of 15 TSC2 VUS. We investigated the effects of the variants on the formation of the TSC complex, on TORC1 activity and on TSC2 pre‐mRNA splicing. In 13 cases (87%), the functional data supported the hypothesis that the identified TSC2 variant caused TSC. Our results illustrate the benefits and limitations of functional testing for TSC.
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Affiliation(s)
- Luiz G Dufner Almeida
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Santoesha Nanhoe
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Andrea Zonta
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Mitra Hosseinzadeh
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Regina Kom-Gortat
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Peter Elfferich
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Gerben Schaaf
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Annegien Kenter
- Department of Developmental Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Daniel Kümmel
- Biochemistry and Structural Biology Section, Institute of Biochemistry, University of Munster, Munster, Germany
| | - Nicola Migone
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Sue Povey
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Rosemary Ekong
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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Ekong R, Vihinen M. Checklist for gene/disease-specific variation database curators to enable ethical data management. Hum Mutat 2019; 40:1634-1640. [PMID: 31347738 DOI: 10.1002/humu.23881] [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: 04/17/2019] [Revised: 07/16/2019] [Accepted: 07/22/2019] [Indexed: 11/10/2022]
Abstract
Databases with variant and phenotype information are essential for advancing research and improving the health and welfare of individuals. These resources require data to be collected, curated, and shared among relevant specialties to maximize impact. The increasing generation of data which must be shared both nationally and globally for maximal effect presents important ethical and privacy concerns. Database curators need to ensure that their work conform to acceptable ethical standards. A Working Group of the Human Variome Project had the task of updating and streamlining ethical guidelines for locus-specific/gene variant database curators. In this article, we present practical and achievable steps which should assist database curators in carrying out their responsibilities within acceptable ethical norms.
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Affiliation(s)
- Rosemary Ekong
- Department of Genetics, Evolution & Environment, University College London, London, UK
| | - Mauno Vihinen
- Department of Experimental Medical Science, BMC B13, Lund University, Lund, Sweden
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11
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Farach LS, Pearson DA, Woodhouse JP, Schraw JM, Sahin M, Krueger DA, Wu JY, Bebin EM, Lupo PJ, Au KS, Northrup H. Tuberous Sclerosis Complex Genotypes and Developmental Phenotype. Pediatr Neurol 2019; 96:58-63. [PMID: 31005478 PMCID: PMC6837240 DOI: 10.1016/j.pediatrneurol.2019.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Children with tuberous sclerosis complex (TSC), caused by pathogenic variants in TSC1/TSC2, are at risk for intellectual disability. TSC2 pathogenic variants appear to increase the risk, compared with TSC1. However, the effect of TSC2 pathogenic variants on early and specific domains of development hasn't been studied. Using an extensively phenotyped group, we aimed to characterize differences in early intellectual development between genotypes. METHODS The study group (n = 92) included participants with TSC enrolled in a multicenter study involving genetic testing and detailed prospective phenotyping including the Mullen Scales of Early Learning, a validated measure of cognition, language, and motor development in babies and preschool children. Mean T-scores at 24 months for each Mullen Scales of Early Learning domain were calculated for children with, versus without, a TSC2 pathogenic variant. Multivariable linear regression models were used to compare the groups, adjusting for seizures. RESULTS T-scores on every Mullen Scales of Early Learning domain were significantly worse in the TSC2 group. Below average composite scores were present in three-fourths of the TSC2 group, compared with one-fourth of those without TSC2. Having a TSC2 pathogenic variant was associated with lower composite Mullen Scales of Early Learning scores, even when corrected for seizures. CONCLUSIONS In a well-characterized patient population with standardized assessment of multiple aspects of development, we found that having a TSC2 pathogenic variant was associated with significantly lower Mullen Scales of Early Learning scores at age 24 months, independent of seizures. These data suggest that a baby with a TSC2 pathogenic variant is at high risk for significant developmental delays by 24 months.
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Affiliation(s)
- Laura S. Farach
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas,Communications should he addressed to: Laura S. Farach; 6431 Fannin Street MSB 3.142; Houston, TX 77030., (L.S. Farach)
| | - Deborah A. Pearson
- Department of Psychiatry, Division of Child and Adolescent Psychiatry, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - John P. Woodhouse
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Jeremy M. Schraw
- Department of Medicine, Section of Epidemiology and Population Sciences, 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
| | | | - Philip J. Lupo
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Kit Sing Au
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Hope Northrup
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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12
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Salussolia CL, Klonowska K, Kwiatkowski DJ, Sahin M. Genetic Etiologies, Diagnosis, and Treatment of Tuberous Sclerosis Complex. Annu Rev Genomics Hum Genet 2019; 20:217-240. [PMID: 31018109 DOI: 10.1146/annurev-genom-083118-015354] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems due to an inactivating variant in either TSC1 or TSC2, resulting in the hyperactivation of the mechanistic target of rapamycin (mTOR) pathway. Dysregulated mTOR signaling results in increased cell growth and proliferation. Clinically, TSC patients exhibit great phenotypic variability, but the neurologic and neuropsychiatric manifestations of the disease have the greatest morbidity and mortality. TSC-associated epilepsy occurs in nearly all patients and is often difficult to treat because it is refractory to multiple antiseizure medications. The advent of mTOR inhibitors offers great promise in the treatment of TSC-associated epilepsy and other neurodevelopmental manifestations of the disease; however, the optimal timing of therapeutic intervention is not yet fully understood.
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Affiliation(s)
- Catherine L Salussolia
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Katarzyna Klonowska
- Division of Pulmonary and Critical Care Medicine and Division of Genetics, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David J Kwiatkowski
- Division of Pulmonary and Critical Care Medicine and Division of Genetics, Brigham and Women's Hospital and 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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13
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Ye Y, Zeng Y. Whole exome sequencing identifies a novel intron heterozygous mutation in TSC2 responsible for tuberous sclerosis complex. Sci Rep 2019; 9:4456. [PMID: 30872599 PMCID: PMC6418313 DOI: 10.1038/s41598-019-38898-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/21/2018] [Indexed: 11/09/2022] Open
Abstract
This study was aimed to identify the potentially pathogenic gene variants that contribute to the etiology of the tuberous sclerosis complex. A Chinese pedigree with tuberous sclerosis complex was collected and the exomes of two affected individuals were sequenced using the whole exome sequencing technology. The resulting variants from whole exome sequencing were filtered by basic and advanced biological information analysis and the candidate mutation was verified as heterozygous by sanger sequencing. After basic and advanced biological information analysis, a total of 9 single nucleotide variants were identified, which were all follow the dominant inheritance pattern. Among which, the intron heterozygous mutation c.600-145 C > T transition in TSC2 was identified and validated in the two affected individuals. In silico analysis with human splicing finder (HSF) predicted the effect of the c.600-145 C > T mutations on TSC2 mRNA splicing, and detected the creation of a new exonic cryptic donor site, which would result in a frame-shift, and finally premature termination codon. Our results reported the novel intron heterozygous mutation c.600-145 C > T in TSC2 may contribute to TSC, expanding our understanding of the causally relevant genes for this disorder.
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Affiliation(s)
- Yicong Ye
- Department of Cardiology, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China.,Department of Cardiology, Chinese Academy of Medical College and Peking Union Medical College Hospital; Peking Union Medical College Hospital, Beijing, 100730, China
| | - Yong Zeng
- Department of Cardiology, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China. .,Department of Cardiology, Chinese Academy of Medical College and Peking Union Medical College Hospital; Peking Union Medical College Hospital, Beijing, 100730, China.
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14
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Peron A, Au KS, Northrup H. Genetics, genomics, and genotype-phenotype correlations of TSC: Insights for clinical practice. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2018; 178:281-290. [PMID: 30255984 DOI: 10.1002/ajmg.c.31651] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/22/2018] [Indexed: 01/28/2023]
Abstract
Tuberous Sclerosis Complex (TSC) is a multisystem autosomal dominant condition caused by inactivating pathogenic variants in either the TSC1 or the TSC2 gene, leading to hyperactivation of the mTOR pathway. Here, we present an update on the genetic and genomic aspects of TSC, with a focus on clinical and laboratory practice. We briefly summarize the structure of TSC1 and TSC2 as well as their protein products, and discuss current diagnostic testing, addressing mosaicism. We consider genotype-phenotype correlations as an example of precision medicine, and discuss genetic counseling in TSC, with the aim of providing geneticists and health care practitioners involved in the care of TSC individuals with useful tools for their practice.
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Affiliation(s)
- Angela Peron
- Child Neuropsychiatry Unit-Epilepsy Center (Service of Medical Genetics), San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy.,Department of Pediatrics, Division of Medical Genetics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Kit Sing Au
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Hope Northrup
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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15
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Cui J, Yu X, Liang S, Zhang S, Hu X. First five generations Chinese family of tuberous scleroses complex due to a new mutation of the TSC1 gene. J Clin Neurosci 2018; 54:39-44. [PMID: 29803333 DOI: 10.1016/j.jocn.2018.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 02/09/2018] [Accepted: 05/17/2018] [Indexed: 12/11/2022]
Abstract
Tuberous scleroses complex (TSC) is a rare neurocutaneous syndrome and has autosomal dominant inheritance. However, larger family with TSC is very rare. Here, we report the first five generations family with TSC from China, and localize the pathogenic gene. A boy with TSC and epilepsy underwent preoperative evaluation and epileptic surgery. His TSC family history was gotten, and the clinical data of a Chinese family with TSC were collected in 2016. Complete exons sequencing was performed in the proband and his parents, and whole exons sequence of TSC was performed in the other family members. The family showed autosomal dominant inheritance, and it was the largest reported family with TSC. In this pedigree, there were 14 patients in 5 generations, but only 1 case with epilepsy in them. All of examined patients had TSC 1 gene exon 15 c.1846delG p.A616Pfs*13 mutation. In conclusion, TSC patients with TSC 1 deletion presented mild neurological symptom and rendered larger family.
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Affiliation(s)
- Jianfei Cui
- Department of Neurosurgery, First Affiliated Hospital of PLA General Hospital, Beijing, China; First Affiliated Hospital of PLA General Hospital Graduate Training Base, Jinzhou Medical University, Jinzhou, China
| | - Xiaoman Yu
- Department of Neurosurgery, First Affiliated Hospital of PLA General Hospital, Beijing, China
| | - Shuli Liang
- Department of Neurosurgery, First Affiliated Hospital of PLA General Hospital, Beijing, China; First Affiliated Hospital of PLA General Hospital Graduate Training Base, Jinzhou Medical University, Jinzhou, China; Department of Neurosurgery, PLA General Hospital, Beijing, China.
| | - Shaohui Zhang
- Department of Neurosurgery, Capital Epilepsy Therapy Center, First Affiliated Hospital of PLA General Hospital, Beijing, China
| | - Xiaohong Hu
- Department of Pediatric, First Affiliated Hospital of PLA General Hospital, Beijing, China
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16
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Farach LS, Gibson WT, Sparagana SP, Nellist M, Stumpel CTRM, Hietala M, Friedman E, Pearson DA, Creighton SP, Wagemans A, Segel R, Ben-Shalom E, Au KS, Northrup H. TSC2 c.1864C>T variant associated with mild cases of tuberous sclerosis complex. Am J Med Genet A 2017; 173:771-775. [PMID: 28211972 DOI: 10.1002/ajmg.a.38083] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/21/2016] [Indexed: 11/08/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominantly inherited disorder with variable expressivity associated with hamartomatous tumors, abnormalities of the skin, and neurologic problems including seizures, intellectual disability, and autism. TSC is caused by pathogenic variants in either TSC1 or TSC2. In general, TSC2 pathogenic variants are associated with a more severe phenotype than TSC1 pathogenic variants. Here, we report a pathogenic TSC2 variant, c.1864C>T, p.(Arg622Trp), associated with a mild phenotype, with most carriers meeting fewer than two major clinical diagnostic criteria for TSC. This finding has significant implications for counseling patients regarding prognosis. More patient data are required before changing the surveillance recommendations for patients with the reported variant. However, consideration should be given to tailoring surveillance recommendations for all pathogenic TSC1 and TSC2 variants with documented milder clinical sequelae. © 2017 Wiley Periodicals, Inc.
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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
| | - William T Gibson
- Department of Medical Genetics, BC Children's Hospital and UBC, Vancouver, British Columbia, Canada
| | - Steven P Sparagana
- Division of Neurology, Texas Scottish Rite Hospital for Children and University of Texas Southwestern Medical School, Dallas, Texas
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Connie T R M Stumpel
- Department of Clinical Genetics and School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center (MUMC), Maastricht, The Netherlands
| | - Marja Hietala
- Department of Clinical Genetics and Department of Medical Biochemistry and Genetics, University of Turku and Turku University Hospital, Turku, Finland
| | - Elliott Friedman
- Department of Diagnostic and Interventional Imaging, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Deborah A Pearson
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Susan P Creighton
- Department of Medical Genetics, BC Women's Hospital and UBC, Vancouver, British Columbia, Canada
| | - Annemiek Wagemans
- Department of Clinical Genetics and School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center (MUMC), Maastricht, The Netherlands.,Koraalgroep, Maasveld, Maastricht, The Netherlands
| | - Reveel Segel
- Medical Genetics Institute, Shaare Zedek Medical Center and the Hebrew University School of Medicine, Jerusalem, Israel
| | - Efrat Ben-Shalom
- Department of Pediatric Nephrology, Shaare Zedek Medical Center, Jerusalem, Israel
| | - 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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17
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Differential control of ageing and lifespan by isoforms and splice variants across the mTOR network. Essays Biochem 2017; 61:349-368. [PMID: 28698309 DOI: 10.1042/ebc20160086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 11/17/2022]
Abstract
Ageing can be defined as the gradual deterioration of physiological functions, increasing the incidence of age-related disorders and the probability of death. Therefore, the term ageing not only reflects the lifespan of an organism but also refers to progressive functional impairment and disease. The nutrient-sensing kinase mTOR (mammalian target of rapamycin) is a major determinant of ageing. mTOR promotes cell growth and controls central metabolic pathways including protein biosynthesis, autophagy and glucose and lipid homoeostasis. The concept that mTOR has a crucial role in ageing is supported by numerous reports on the lifespan-prolonging effects of the mTOR inhibitor rapamycin in invertebrate and vertebrate model organisms. Dietary restriction increases lifespan and delays ageing phenotypes as well and mTOR has been assigned a major role in this process. This may suggest a causal relationship between the lifespan of an organism and its metabolic phenotype. More than 25 years after mTOR's discovery, a wealth of metabolic and ageing-related effects have been reported. In this review, we cover the current view on the contribution of the different elements of the mTOR signalling network to lifespan and age-related metabolic impairment. We specifically focus on distinct roles of isoforms and splice variants across the mTOR network. The comprehensive analysis of mouse knockout studies targeting these variants does not support a tight correlation between lifespan prolongation and improved metabolic phenotypes and questions the strict causal relationship between them.
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