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Published on: August 20, 2019
Adult Phenotype of CHD2-Associated Disorders.
Marlene Rong1, Quratulain Zulfiqar Ali1, Angel Aledo-Serrano1
1From the Institute of Medical Science (M.R.), University of Toronto; Adult Genetic Epilepsy (AGE) Program (M.R., Q.Z.A., F.Q., I.C., A.A., D.M.A.), Krembil Neurosciences Institute, Toronto Western Hospital, University Health Network, Canada; Epilepsy Unit (A.A.-S.), Vithas Clinical Neuroscience Institute, Vithas Madrid University Hospitals; Faculty of Experimental Sciences (A.A.-S.), Francisco de Vitoria University, Madrid, Spain; Department of Drug Design and Pharmacology (A.B.), University of Copenhagen; Department for Genetics and Personalized Medicine (A.B.), Danish Epilepsy Centre, Dianalund; Institute for Regional Health Services (A.B.), University of Southern Denmark, Odense; NYU Langone Epilepsy Center (O.D., F.Q., A.A.); Edmond J. Safra Program in Parkinson's Disease (A.F.), Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN; Division of Neurology (A.F., D.M.A.), Department of Medicine, University of Toronto; Krembil Brain Institute (A.F., D.M.A.); Clinical Genetics Research Program (A.S.B.), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (A.S.B.), Toronto General Hospital, University Health Network; Department of Psychiatry (A.S.B.), University of Toronto, Ontario; Toronto Congenital Cardiac Centre for Adults (A.S.B.), Division of Cardiology, Department of Medicine, and Department of Psychiatry, University Health Network and Toronto General Hospital Research Institute and Campbell Family Mental Health Research Institute (A.S.B.), Toronto, Ontario, Canada.
Adults with CHD2 variants often experience ongoing seizures and significant comorbidities, including behavioral issues and mobility challenges. Seizure severity correlates with worse nonseizure outcomes, impacting daily living and quality of life.
Area of Science:
- Neurogenetics
- Clinical Neurology
- Developmental Neuroscience
Background:
- Pathogenic CHD2 variants are linked to neurodevelopmental disorders and epileptic encephalopathy.
- While pediatric phenotypes are well-documented, adult manifestations of CHD2 variants remain less understood.
- This study focuses on characterizing the adult phenotypic spectrum of CHD2 variants.
Purpose of the Study:
- To investigate the phenotypic spectrum of adult patients (≥18 years) carrying likely pathogenic or pathogenic (LP/P) CHD2 variants.
- To evaluate seizures, medication use, sleep, gastrointestinal symptoms, pain response, gait, social communication, and adaptive behaviors in this cohort.
- To provide insights into the natural history and long-term outcomes of CHD2-related disorders in adults.
Main Methods:
- Prospective study of 14 unrelated adult patients (18-45 years) with LP/P CHD2 variants.
- Utilized standardized tools to assess various clinical and functional domains.
- Included genetic analysis to identify CHD2 variants, with 11 novel variants discovered.
Main Results:
- 79% of adult patients reported ongoing seizures, with 64% exhibiting photosensitivity.
- High prevalence of autism spectrum disorder (71%) and behavioral issues (100%), including internalizing features (71%) and self-injurious behaviors (50%).
- Significant functional impairments noted: 43% ambulated independently, only 29% had sixth-grade reading comprehension, and none could perform all daily living activities independently consistently. Higher seizure severity correlated with worse nonseizure outcomes (p=0.04).
Conclusions:
- Adults with CHD2 variants frequently experience persistent seizures and a high burden of comorbidities.
- Seizure severity is a significant factor associated with poorer nonseizure outcomes, affecting behavior, mobility, and physiological functions.
- These findings highlight the need for comprehensive management strategies and inform prognostic expectations for families and future therapeutic development.
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