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Mochel F, Rastetter A, Ceulemans B, Platzer K, Yang S, Shinde DN, Helbig KL, Lopergolo D, Mari F, Renieri A, Benetti E, Canitano R, Waisfisz Q, Plomp AS, Huisman SA, Wilson GN, Cathey SS, Louie RJ, Gaudio DD, Waggoner D, Kacker S, Nugent KM, Roeder ER, Bruel AL, Thevenon J, Ehmke N, Horn D, Holtgrewe M, Kaiser FJ, Kamphausen SB, Abou Jamra R, Weckhuysen S, Dalle C, Depienne C. Variants in the SK2 channel gene (KCNN2) lead to dominant neurodevelopmental movement disorders. Brain 2020; 143:3564-3573. [PMID: 33242881 DOI: 10.1093/brain/awaa346] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/17/2020] [Accepted: 09/08/2020] [Indexed: 11/14/2022] Open
Abstract
KCNN2 encodes the small conductance calcium-activated potassium channel 2 (SK2). Rodent models with spontaneous Kcnn2 mutations show abnormal gait and locomotor activity, tremor and memory deficits, but human disorders related to KCNN2 variants are largely unknown. Using exome sequencing, we identified a de novo KCNN2 frameshift deletion in a patient with learning disabilities, cerebellar ataxia and white matter abnormalities on brain MRI. This discovery prompted us to collect data from nine additional patients with de novo KCNN2 variants (one nonsense, one splice site, six missense variants and one in-frame deletion) and one family with a missense variant inherited from the affected mother. We investigated the functional impact of six selected variants on SK2 channel function using the patch-clamp technique. All variants tested but one, which was reclassified to uncertain significance, led to a loss-of-function of SK2 channels. Patients with KCNN2 variants had motor and language developmental delay, intellectual disability often associated with early-onset movement disorders comprising cerebellar ataxia and/or extrapyramidal symptoms. Altogether, our findings provide evidence that heterozygous variants, likely causing a haploinsufficiency of the KCNN2 gene, lead to novel autosomal dominant neurodevelopmental movement disorders mirroring phenotypes previously described in rodents.
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Affiliation(s)
- Fanny Mochel
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013 Paris, France.,AP-HP, Hôpital Pitié-Salpêtrière, Département de Génétique and Centre de Référence Neurométabolique Adulte, F-75013, Paris, France
| | - Agnès Rastetter
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013 Paris, France
| | - Berten Ceulemans
- Division of Paediatric Neurology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | | | - Deepali N Shinde
- Department of Clinical Diagnostics, Ambry Genetics, Aliso Viejo, CA, USA
| | - Katherine L Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Diego Lopergolo
- Medical Genetics, University of Siena, Siena, Italy.,Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Francesca Mari
- Medical Genetics, University of Siena, Siena, Italy.,Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Alessandra Renieri
- Medical Genetics, University of Siena, Siena, Italy.,Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Elisa Benetti
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Roberto Canitano
- Division of Child and Adolescent Neuropsychiatry, University Hospital of Siena, Siena, Italy
| | - Quinten Waisfisz
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Astrid S Plomp
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Sylvia A Huisman
- Department of Pediatrics, Amsterdam UMC, Amsterdam, The Netherlands.,Prinsenstichting, Purmerend, The Netherlands
| | - Golder N Wilson
- Department of Pediatrics, Texas Tech University Health Science Center, Lubbock, Texas, USA
| | - Sara S Cathey
- Greenwood Genetic Center, Greenwood, South Carolina, 29646, USA
| | - Raymond J Louie
- Department of Human Genetics, University of Chicago, Chicago, IL, 60637, USA
| | - Daniela Del Gaudio
- Department of Human Genetics, University of Chicago, Chicago, IL, 60637, USA
| | - Darrel Waggoner
- Department of Human Genetics, University of Chicago, Chicago, IL, 60637, USA
| | - Shawn Kacker
- Department of Pediatrics, Section of Child Neurology, University of Chicago, Chicago, IL, 60637, USA
| | - Kimberly M Nugent
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX, 78207, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Elizabeth R Roeder
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX, 78207, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Ange-Line Bruel
- UMR1231 GAD, Inserm - Université Bourgogne-Franche Comté, Dijon, France.,Centre de référence maladies rares 'déficiences intellectuelles de causes rares', Centre de Génétique, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Julien Thevenon
- Service de Génétique, Génomique, et Procréation, Centre Hospitalier Universitaire Grenoble Alpes, 38700 La Tronche, France.,INSERM 1209, CNRS UMR 5309, Institute for Advanced Biosciences, Université Grenoble Alpes, 38706 Grenoble, France
| | - Nadja Ehmke
- Institute for Human Genetics and Medical Genetics, Charité - Universitaetsmedizin Berlin, Berlin, Germany
| | - Denise Horn
- Institute for Human Genetics and Medical Genetics, Charité - Universitaetsmedizin Berlin, Berlin, Germany
| | - Manuel Holtgrewe
- Core Unit Bioinformatics - CUBI, Berlin Institute of Health (BIH), Berlin, Germany
| | - Frank J Kaiser
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147 Essen, Germany
| | | | - Rami Abou Jamra
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Sarah Weckhuysen
- Applied and Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium.,Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Carine Dalle
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013 Paris, France
| | - Christel Depienne
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013 Paris, France.,Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147 Essen, Germany
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