Related Experiment Video
Updated: Jul 6, 2025

In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila
Published on: August 20, 2019
Molecular and Phenotypic Characterization of the RORB-Related Disorder
Zeynep Gokce-Samar1, Annalisa Vetro1, Julitta De Bellescize1
1From the Department of Pediatric Clinical Epileptology (Z.G.-S., J.D.B., A.A.A.), Sleep Disorders and Functional Neurology, University Hospitals of Lyon, HCL, Member of ERN Epicare, France; Neuroscience Department (A.V., T.P., R.G.) IRCCS, Children's Hospital Meyer, Member of ERN Epicare, and University of Florence, Italy; Univ Lyon (L.M., N.P., D.S., N.C., J.C., G.L.), Univ Lyon 1, CNRS, INSERM, Physiopathologie et Génétique du Neurone et du Muscle, UMR5261, U1315, Institut NeuroMyoGène, France; Pediatric Neurology Unit (C.M.K., J.F.), University Hospitals of Geneva, Switzerland; Child Neurology and Psychiatric Unit (C.M., E.C.), Children's Hospital G. Salesi, Azienda Universitaria Ospedaliera delle Marche, Ancona, Italy; Department of Neurology (B.M.A.), University Hospitals of Montpellier; Department of Genetics (D.S., N.C., A. Labalme, G.L.), University Hospitals of Lyon, HCL, Member of ERN Epicare, France; Paediatric Epilepsy Research (A.A.A.), Child Neurology Department, Member of the ERN EpiCARE, San Juan de Dios Children's Hospital, Barcelona, Spain; Division of Neurology (V.A.C., S.M.R., I.H.), and The Epilepsy NeuroGenetics Initiative (ENGIN) (V.A.C., S.M.R., K.L.H., I.H.), Children's Hospital of Philadelphia, PA; Department of Neurology (V.A.C., S.M.R., I.H.), University of Pennsylvania Perelman School of Medicine, Philadelphia; Univ Rouen Normandie (F.L., G.N.), Inserm U1245 and CHU Rouen, Department of Genetics and Reference Center for Developmental Disorders; Department of Pediatric Neurology (G.A.M., A. Lebas), University Hospitals of Rouen; Department of Pediatric Neurology (H.O.T.), Hospital of Alpes Léman, Annemasse, France; Department of Pediatric Neurology (A.R.), Barcelona Children's Hospital, University of Barcelona, Spain; Developmental Neurosciences (A.N., M.A.K., K.R., R.S.), Zayed Centre for Research, University College of London, Great Ormond Street Hospital, Institute of Child Health, United Kingdom; Institute of Medical Genetics (P.J.), University of Zürich; Department of Neuropediatrics (G. Ramantani, K.S.), University Children's Hospital and University of Zürich, Switzerland; Department of Neurology (M.K.), Medical University of Vienna, Austria; Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics (L.G.), Department of Pediatrics, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany; Institute of Human Genetics (S.V.), Medical University of Innsbruck, Innsbruck, Austria; Werner-Forßmann-Krankenhaus (S.V., S.T.), Eberswalde, Germany; Pediatric Neurology Discipline (D.C.), Neurosciences Department, Carol Davila University of Medicine Bucharest; Pediatric Neurology Clinic (D.C.), Al Obregia Hospital, Center of Expertise for Pediatric Neurology Rare Disorders, Member of ERN EpiCARE, Bucharest, Romania; Institute of Clinical Molecular Biology (M.P., I.H.), Christian-Albrechts-University of Kiel, Germany; Mission Fullerton Genetics Center (C.H.-E.), Asheville, NC; Department of Neurology (I.K.), Svt. Luka's Institute of Child Neurology and Epilepsy, Moscow; Department of Medical Genetics (I.R.), Kazan State University, Russia; Division of Child Neurology (D.S.R.), Department of Pediatrics, UPMC Children's Hospital of Pittsburgh, PA; Department of Molecular and Human Genetics (J.A.R.), Baylor College of Medicine, Houston, TX; Division of Clinical Genetics and Dysmorphology (M.A., K.G., J.M.G.), Cedars-Sinai Medical Center, Los Angeles, CA; Department of Neurology (A.I.), University Hospitals of Armand Trousseau, AP-HP, Paris; Department of Pediatric Neurology (N.V.), University Hospitals of Marseille, AP-HM; Univ. Lille (T.S.), CHU Lille, ULR7364, RADEME, Institute of Medical Genetics; Department of Clinical Genetics (R.C.), CHU Lille, France; Institute of Human Genetics (P.Z., S.N., K.P., T.B., I.M., M.R., R.A.J.), University of Leipzig Medical Center, Germany; Institute of Human Genetics (S.T.), Medical University of Innsbruck, Austria; Department of Biomedical and Health Informatics (DBHi) (I.H.), Children's Hospital of Philadelphia, PA; Department of Pediatric Neurology (F.E.J., K.K.), Brain Center UMC Utrecht, Member of ERN Epicare, Utrecht, the Netherlands; Department of Neurology (G. Rudolf), Strasbourg University Hospital; and Nantes Université (S.K.), CHU Nantes, Service de Génétique Médicale, and CNRS, INSERM, l'institut du thorax, France.
Pathogenic variants in the RORB gene are linked to epilepsy and intellectual disability (ID). This study confirms RORB variants cause absence seizures and ID, with impaired axonal function.
Area of Science:
- Genetics
- Neuroscience
- Molecular Biology
Background:
- Heterozygous variants in RAR-related orphan receptor B (RORB) are associated with idiopathic generalized epilepsy.
- Limited reports exist on pathogenic RORB variants in patients with epilepsy and intellectual disability (ID).
Purpose of the Study:
- To delineate the epilepsy phenotype associated with RORB pathogenic variants.
- To provide evidence supporting the pathogenicity of RORB variants.
Main Methods:
- International cohort analysis of seizure characteristics, EEG, and genotypes in patients with heterozygous RORB variants.
- Ex vivo cortical electroporation in mouse embryos for 5 selected RORB variants (2 truncating, 3 missense) to assess expression and axonal morphology.
Main Results:
- Identified 35 patients with 32 different heterozygous RORB variants; 89% experienced seizures, predominantly absence seizures (81%).
- 85% of patients exhibited intellectual disability (ID) of variable degree.
- In vitro studies showed shorter axons for tested RORB variants, indicating impaired protein function.
Conclusions:
- The RORB-related disorder typically presents with absence seizures and mild-to-moderate ID.
- In silico and in vitro evaluations support the pathogenicity of RORB variants, demonstrating a hypomorphic effect.
Related Concept Videos
Oppositional Defiant Disorder
Diagnostic Criteria and...
Pleiotropy
Pedigree Analysis
The Retinoblastoma Gene
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
Ribosome Profiling
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique...
Genetic Lingo

