Michael Zech1,2, Robert Jech3, Petra Havránková3, Anna Fečíková3, Riccardo Berutti4, Dušan Urgošík5, David Kemlink3, Tim M Strom4,6, Jan Roth3, Evžen Růžička3, Juliane Winkelmann1,2,6,7. 1. Institut für Neurogenomik, Helmholtz Zentrum München, Munich, Germany. 2. Klinik und Poliklinik für Neurologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. 3. Department of Neurology and Center of Clinical Neuroscience, First Faculty of Medicine, Charles University and General Faculty Hospital, Prague, Czech Republic. 4. Institut für Humangenetik, Helmholtz Zentrum München, Munich, Germany. 5. Department of Stereotactic Neurosurgery and Radiosurgery, Na Homolce Hospital, Prague, Czech Republic. 6. Institut für Humangenetik, Technische Universität München, Munich, Germany. 7. Munich Cluster for Systems Neurology, SyNergy, Munich, Germany.
Abstract
BACKGROUND: Recently a novel syndrome of childhood-onset generalized dystonia originating from mutations in lysine-specific methyltransferase 2B (KMT2B) has been reported. METHODS: We sequenced the exomes of 4 generalized dystonia-affected probands recruited from a Prague movement disorders center (Czech Republic). Bioinformatics analyses were conducted to select candidate causal variants in described dystonia-mutated genes. After cosegregation testing, checklists from the American College of Medical Genetics and Genomics were adopted to judge variant pathogenicity. RESULTS: Three novel, predicted protein-damaging missense variants in KMT2B were identified (p.Glu1234Lys, p.Ala1541Val, p.Arg1779Gln). Meeting pathogenicity criteria, p.Glu1234Lys was absent from population-based controls, situated in a key protein domain, and had occurred de novo. The associated phenotype comprised adolescence-onset generalized isolated dystonia with prominent speech impairment. Although linked to a similar clinical expression, p.Ala1541Val and p.Arg1779Gln remained of uncertain significance. CONCLUSIONS: Rare missense variation in KMT2B represents an additional cause of generalized dystonia. Application of sequence interpretation standards is required before assigning pathogenicity to a KMT2B missense variant.
BACKGROUND: Recently a novel syndrome of childhood-onset generalized dystonia originating from mutations in lysine-specific methyltransferase 2B (KMT2B) has been reported. METHODS: We sequenced the exomes of 4 generalized dystonia-affected probands recruited from a Prague movement disorders center (Czech Republic). Bioinformatics analyses were conducted to select candidate causal variants in described dystonia-mutated genes. After cosegregation testing, checklists from the American College of Medical Genetics and Genomics were adopted to judge variant pathogenicity. RESULTS: Three novel, predicted protein-damaging missense variants in KMT2B were identified (p.Glu1234Lys, p.Ala1541Val, p.Arg1779Gln). Meeting pathogenicity criteria, p.Glu1234Lys was absent from population-based controls, situated in a key protein domain, and had occurred de novo. The associated phenotype comprised adolescence-onset generalized isolated dystonia with prominent speech impairment. Although linked to a similar clinical expression, p.Ala1541Val and p.Arg1779Gln remained of uncertain significance. CONCLUSIONS: Rare missense variation in KMT2B represents an additional cause of generalized dystonia. Application of sequence interpretation standards is required before assigning pathogenicity to a KMT2B missense variant.
Authors: Laura Cif; Diane Demailly; Jean-Pierre Lin; Katy E Barwick; Mario Sa; Lucia Abela; Sony Malhotra; Wui K Chong; Dora Steel; Alba Sanchis-Juan; Adeline Ngoh; Natalie Trump; Esther Meyer; Xavier Vasques; Julia Rankin; Meredith W Allain; Carolyn D Applegate; Sanaz Attaripour Isfahani; Julien Baleine; Bettina Balint; Jennifer A Bassetti; Emma L Baple; Kailash P Bhatia; Catherine Blanchet; Lydie Burglen; Gilles Cambonie; Emilie Chan Seng; Sandra Chantot Bastaraud; Fabienne Cyprien; Christine Coubes; Vincent d'Hardemare; Asif Doja; Nathalie Dorison; Diane Doummar; Marisela E Dy-Hollins; Ellyn Farrelly; David R Fitzpatrick; Conor Fearon; Elizabeth L Fieg; Brent L Fogel; Eva B Forman; Rachel G Fox; William A Gahl; Serena Galosi; Victoria Gonzalez; Tracey D Graves; Allison Gregory; Mark Hallett; Harutomo Hasegawa; Susan J Hayflick; Ada Hamosh; Marie Hully; Sandra Jansen; Suh Young Jeong; Joel B Krier; Sidney Krystal; Kishore R Kumar; Chloé Laurencin; Hane Lee; Gaetan Lesca; Laurence Lion François; Timothy Lynch; Neil Mahant; Julian A Martinez-Agosto; Christophe Milesi; Kelly A Mills; Michel Mondain; Hugo Morales-Briceno; John R Ostergaard; Swasti Pal; Juan C Pallais; Frédérique Pavillard; Pierre-Francois Perrigault; Andrea K Petersen; Gustavo Polo; Gaetan Poulen; Tuula Rinne; Thomas Roujeau; Caleb Rogers; Agathe Roubertie; Michelle Sahagian; Elise Schaefer; Laila Selim; Richard Selway; Nutan Sharma; Rebecca Signer; Ariane G Soldatos; David A Stevenson; Fiona Stewart; Michel Tchan; Ishwar C Verma; Bert B A de Vries; Jenny L Wilson; Derek A Wong; Raghda Zaitoun; Dolly Zhen; Anna Znaczko; Russell C Dale; Claudio M de Gusmão; Jennifer Friedman; Victor S C Fung; Mary D King; Shekeeb S Mohammad; Luis Rohena; Jeff L Waugh; Camilo Toro; F Lucy Raymond; Maya Topf; Philippe Coubes; Kathleen M Gorman; Manju A Kurian Journal: Brain Date: 2020-12-05 Impact factor: 13.501