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Bonnet JB, Durieux AT, Tournayre S, Marty L, Sultan A, Avignon A. Semaglutide as a potential treatment for obesity in Smith-Kingsmore syndrome (SKS) patients: A mosaic mutation case report. Obes Res Clin Pract 2024; 18:159-162. [PMID: 38582735 DOI: 10.1016/j.orcp.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 03/22/2024] [Accepted: 03/28/2024] [Indexed: 04/08/2024]
Abstract
We present for the first-time efficacy and tolerability of GLP-1-RA (Semaglutide) in Smith-Kingsmore syndrome (SKS). SKS is a rare genetic disorder characterized by intellectual disability, macrocephaly, seizures and distinctive facial features due to MTOR gene mutation. We present a 22-year-old woman with mosaic SKS and severe obesity (Body Mass Index ≥40 kg/m²), treated with semaglutide. She achieved a 9 kg (7.44%) weight loss over 12 months without adverse effects.This case highlights semaglutide's potential in managing obesity in SKS patients, emphasizing the need for further research in this rare genetic disorder.
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Affiliation(s)
- Jean-Baptiste Bonnet
- Nutrition-Diabetes Department, University Hospital of Montpellier, Montpellier, France; UMR 1302, Institute Desbrest of Epidemiology and Public Health, Univ Montpellier, INSERM, University Hospital of Montpellier, Montpellier, France.
| | | | - Sarah Tournayre
- Nutrition-Diabetes Department, University Hospital of Montpellier, Montpellier, France
| | - Lucile Marty
- Nutrition-Diabetes Department, University Hospital of Montpellier, Montpellier, France
| | - Ariane Sultan
- Nutrition-Diabetes Department, University Hospital of Montpellier, Montpellier, France; PhyMedExp, University of Montpellier, INSERM U1046, CNRS UMR 9214, Montpellier, France
| | - Antoine Avignon
- Nutrition-Diabetes Department, University Hospital of Montpellier, Montpellier, France; UMR 1302, Institute Desbrest of Epidemiology and Public Health, Univ Montpellier, INSERM, University Hospital of Montpellier, Montpellier, France
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Functional and structural analyses of novel Smith-Kingsmore Syndrome-Associated MTOR variants reveal potential new mechanisms and predictors of pathogenicity. PLoS Genet 2021; 17:e1009651. [PMID: 34197453 PMCID: PMC8279410 DOI: 10.1371/journal.pgen.1009651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 07/14/2021] [Accepted: 06/08/2021] [Indexed: 12/31/2022] Open
Abstract
Smith-Kingsmore syndrome (SKS) is a rare neurodevelopmental disorder characterized by macrocephaly/megalencephaly, developmental delay, intellectual disability, hypotonia, and seizures. It is caused by dominant missense mutations in MTOR. The pathogenicity of novel variants in MTOR in patients with neurodevelopmental disorders can be difficult to determine and the mechanism by which variants cause disease remains poorly understood. We report 7 patients with SKS with 4 novel MTOR variants and describe their phenotypes. We perform in vitro functional analyses to confirm MTOR activation and interrogate disease mechanisms. We complete structural analyses to understand the 3D properties of pathogenic variants. We examine the accuracy of relative accessible surface area, a quantitative measure of amino acid side-chain accessibility, as a predictor of MTOR variant pathogenicity. We describe novel clinical features of patients with SKS. We confirm MTOR Complex 1 activation and identify MTOR Complex 2 activation as a new potential mechanism of disease in SKS. We find that pathogenic MTOR variants disproportionately cluster in hotspots in the core of the protein, where they disrupt alpha helix packing due to the insertion of bulky amino acid side chains. We find that relative accessible surface area is significantly lower for SKS-associated variants compared to benign variants. We expand the phenotype of SKS and demonstrate that additional pathways of activation may contribute to disease. Incorporating 3D properties of MTOR variants may help in pathogenicity classification. We hope these findings may contribute to improving the precision of care and therapeutic development for individuals with SKS. Smith-Kingsmore Syndrome is a rare disease caused by damage in a gene named MTOR that is associated with excessive growth of the head and brain, delays in development and deficits in intellectual functioning. We report 7 patients who have changes in MTOR that have never been reported before. We describe new medical findings in these patients that may be common in Smith-Kingsmore Syndrome more broadly. We then identify how these new gene changes impact the function of the MTOR protein and thus cell function downstream. Lastly, we show that changes in the gene that lie deep inside the 3D structure of the MTOR protein are more likely to cause disease than those changes that lie on the surface of the protein. We may be able to use the 3D properties of MTOR gene changes to predict if future changes we see are likely to cause disease or not.
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Poole RL, Curry PDK, Marcinkute R, Brewer C, Coman D, Hobson E, Johnson D, Lynch SA, Saggar A, Searle C, Scurr I, Turnpenny PD, Vasudevan P, Tatton-Brown K. Delineating the Smith-Kingsmore syndrome phenotype: Investigation of 16 patients with the MTOR c.5395G > A p.(Glu1799Lys) missense variant. Am J Med Genet A 2021; 185:2445-2454. [PMID: 34032352 DOI: 10.1002/ajmg.a.62350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/16/2021] [Indexed: 01/06/2023]
Abstract
Smith-Kingsmore Syndrome (SKS) is a rare genetic syndrome associated with megalencephaly, a variable intellectual disability, autism spectrum disorder, and MTOR gain of function variants. Only 30 patients with MTOR missense variants are published, including 14 (47%) with the MTOR c.5395G>A p.(Glu1799Lys) variant. Limited phenotypic data impacts the quality of information delivered to families and the robustness of interpretation of novel MTOR missense variation. This study aims to improve our understanding of the SKS phenotype through the investigation of 16 further patients with the MTOR c.5395G>A p.(Glu1799Lys) variant. Through the careful phenotypic evaluation of these 16 patients and integration with data from 14 previously reported patients, we have defined major (100% patients) and frequent (>15%) SKS clinical characteristics and, using these data, proposed guidance for evidence-based management. In addition, in the absence of functional studies, we suggest that the combination of the SKS major clinical features of megalencephaly (where the head circumference is at least 3SD) and an intellectual disability with a de novo MTOR missense variant (absent from population databases) should be considered diagnostic for SKS.
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Affiliation(s)
- Rebecca L Poole
- NHS Education for Scotland South East Region, South East of Scotland Clinical Genetics Service, Edinburgh, UK.,University College London, London, UK
| | | | - Ruta Marcinkute
- Department of Clinical Genetics, Guys and St Thomas' NHS Foundation Trust, London, UK
| | - Carole Brewer
- Department of Clinical Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
| | - David Coman
- Department of Metabolic Medicine, Queensland Children's Hospital, Queensland, Australia
| | - Emma Hobson
- Department of Clinical Genetics, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Diana Johnson
- Department of Clinical Genetics, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Sally Ann Lynch
- Department of Clinical Genetics, Temple Street Children's University Hospital, Dublin, Ireland
| | - Anand Saggar
- South West Thames Regional Genetics Department, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Claire Searle
- Department of Clinical Genetics, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Ingrid Scurr
- Department of Clinical Genetics, University Hospital Bristol and Western NHS Foundation Trust, Bristol, UK
| | - Peter D Turnpenny
- Department of Clinical Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
| | - Pradeep Vasudevan
- Department of Clinical Genetics, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Katrina Tatton-Brown
- St George's University of London, London, UK.,South West Thames Regional Genetics Department, St George's University Hospitals NHS Foundation Trust, London, UK
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Carli D, Ferrero GB, Fusillo A, Coppo P, La Selva R, Zinali F, Cardaropoli S, Ranieri C, Iacoviello M, Resta N, Mussa A. A new case of Smith-Kingsmore syndrome with somatic MTOR pathogenic variant expands the phenotypic spectrum to lateralized overgrowth. Clin Genet 2021; 99:719-723. [PMID: 33506498 DOI: 10.1111/cge.13931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/08/2021] [Accepted: 01/25/2021] [Indexed: 12/13/2022]
Abstract
Smith-Kingsmore syndrome (SKS) is a rare autosomal dominant disorder caused by heterozygous germline activating pathogenic variants in mammalian target of rapamycin (MTOR) on chromosome 1p36. A few patients with disseminated mosaicism have been described so far and they seem to display a different phenotype when compared to germline cases. Here we report the sixth case with a disseminated mosaic MTOR pathogenic variant, a 7-year-old boy with hemimegalencephaly, epilepsy, developmental delay, hypomelanosis of Ito, and lateralized overgrowth. Genetic testing revealed a pathogenic variant (c.4448G > A, p.Cys1483Tyr) in MTOR with a frequency of 32% in the DNA extracted from a skin sample, 3% in saliva and 0.46% in blood. The clinical features observed in our patient further corroborate the existence of differences in phenotypic presentation of germline and mosaic SKS cases. Moreover, lateralized overgrowth, a finding never described so far in SKS, further expands the phenotypic spectrum of SKS and allows the inclusion of MTOR pathogenic variants among the several causes of asymmetric body overgrowth.
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Affiliation(s)
- Diana Carli
- Pediatric Clinical Genetics Unit, Department of Public Health and Pediatric Sciences, University of Torino and Regina Margherita Children's Hospital, Città della Salute e della Scienza, Torino, Italy
| | | | - Anna Fusillo
- Pediatric Clinical Genetics Unit, Department of Public Health and Pediatric Sciences, University of Torino and Regina Margherita Children's Hospital, Città della Salute e della Scienza, Torino, Italy
| | - Paola Coppo
- Pediatric Dermatology, Regina Margherita Children's Hospital, Città della Salute e della Scienza di Torino, Torino, Italy
| | - Roberta La Selva
- Pediatric Dermatology, Regina Margherita Children's Hospital, Città della Salute e della Scienza di Torino, Torino, Italy
| | - Federica Zinali
- Pediatric Clinical Genetics Unit, Department of Public Health and Pediatric Sciences, University of Torino and Regina Margherita Children's Hospital, Città della Salute e della Scienza, Torino, Italy
| | - Simona Cardaropoli
- Pediatric Clinical Genetics Unit, Department of Public Health and Pediatric Sciences, University of Torino and Regina Margherita Children's Hospital, Città della Salute e della Scienza, Torino, Italy
| | - Carlotta Ranieri
- Department of Biomedical Sciences and Human Oncology (DIMO), Medical Genetics, University of Bari "Aldo Moro", Bari, Italy
| | - Matteo Iacoviello
- Department of Biomedical Sciences and Human Oncology (DIMO), Medical Genetics, University of Bari "Aldo Moro", Bari, Italy
| | - Nicoletta Resta
- Department of Biomedical Sciences and Human Oncology (DIMO), Medical Genetics, University of Bari "Aldo Moro", Bari, Italy
| | - Alessandro Mussa
- Pediatric Clinical Genetics Unit, Department of Public Health and Pediatric Sciences, University of Torino and Regina Margherita Children's Hospital, Città della Salute e della Scienza, Torino, Italy
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