We report a 19-year-old right-handed male with CHD8-related neurodevelopmental disorder (NDD) with overgrowth due to a heterozygous CHD8 pathogenic variant (c.4204C>T) who was admitted to the epilepsy monitoring unit to characterize abnormal involuntary movements. The movements started seven years prior to presentation and were described as rapid jerking, either in isolation or clusters, involving the patient's trunk and/or extremities and associated with intact awareness. Video-EEG captured these movements, which were identified as non-epileptic, multifocal-axial, and appendicular—myoclonus (Videos 1 and 2). The EEG was normal.
Abnormal movements, including dystonia as well as myoclonus, have been associated with CHD8-related NDD.1,2 It is critical to thoroughly evaluate involuntary movements in patients with CHD8-related NDD because this condition is associated with both epilepsy and movement disorders.1,2 Distinguishing the nature of abnormal movements is crucial in formulating the optimal therapeutic plan.
Supplementary Material
SUPPORTING INFORMATION
Additional supporting information can be found online in the Supporting Information section at the end of this article.
VIDEO 1.
Myoclonus. Multiple episodes of multifocal, axial, and appendicular myoclonus were captured, none with ictal EEG correlate. The following examples are shown: (A) (right greater than left) upper extremity myoclonus that is worse with posture/action and lower truncal myoclonus; (B) lower truncal and (right greater than left) lower extremity myoclonus; and (C) truncal followed by right upper extremity myoclonus. Video content can be viewed at https://onlinelibrary.wiley.com/doi/10.1002/epd2.70088.
VIDEO 2.
Video-scalp EEG. Video-scalp EEG captures (right greater than left) upper extremity myoclonus that is worse with posture/action and lower truncal myoclonus events, none with ictal EEG correlate. (Sensitivity: 7 uV/mm, TC: 1 s, HFF: 70 Hz, notch on). Video content can be viewed at https://onlinelibrary.wiley.com/doi/10.1002/epd2.70088.
Test yourself.
- CHD8-related disorder can be associated with all the findings below; which of the following is MOST OFTEN associated with the disorder?
- Seizures
- Autism spectrum disorder
- Hypotonia
- Myoclonus
- Although CHD8-related disorder is an autosomal dominant disorder, most affected individuals have a de novo pathogenic variant.
- True
- False
- How frequently are seizures seen in individuals with CHD8-related disorder?
- 10–15%
- 40–50%
- 70–80%
- 100%
Answers may be found in the supporting information
FUNDING INFORMATION
No targeted funding reported.
Footnotes
CONFLICT OF INTEREST STATEMENT
K.J. Marcinski Nascimento, L. Xavier, and R.M. Guerriero report no disclosures relevant to the manuscript. F. A. Nascimento is Associate Editor of Epileptic Disorders. S.A. Norris currently serves on the Medical and Scientific Review Committee for the Dystonia Medical Research Foundation and Dysphonia International and receives research support from the NIH (R01NS124789) and the Michael J. Fox Foundation.
CONSENT
Patient consent was obtained.
DATA AVAILABILITY STATEMENT
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
REFERENCES
- 1.Mitchel MW, Myers SM, Heidlebaugh AR, Taylor CM, Rea H, Neuhaus E, et al. CHD8-related neurodevelopmental disorder with overgrowth. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews®. Seattle (WA): University of Washington, Seattle; 2022. [PubMed] [Google Scholar]
- 2.Sorrentino U, Boesch S, Doummar D, Ravelli C, Serranova T, Indelicato E, et al. CHD8-related disorders redefined: an expanding spectrum of dystonic phenotypes. J Neurol. 2024;271(5):2859–65. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.