CHD2 myoclonic encephalopathy is frequently associated with self-induced seizures

Rhys H. Thomas, Lin Mei Zhang, Gemma L. Carvill, John S. Archer, Sinéad B. Heavin, Simone A. Mandelstam, Dana Craiu, Samuel F. Berkovic, Deepak S. Gill, Heather C. Mefford, Ingrid E. Scheffer*, EuroEPINOMICS Consortium

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

Objective: To delineate the phenotype of early childhood epileptic encephalopathy due to de novo mutations of CHD2, which encodes the chromodomain helicase DNA binding protein 2. Methods: We analyzed the medical history, MRI, and video-EEG recordings of 9 individuals with de novo CHD2 mutations and one with a de novo 15q26 deletion encompassing CHD2. Results: Seizures began at a mean of 26 months (12-42) with myoclonic seizures in all 10 cases. Seven exhibited exquisite clinical photosensitivity; 6 self-induced with the television. Absence seizures occurred in 9 patients including typical (4), atypical (2), and absence seizures with eyelid myoclonias (4). Generalized tonic-clonic seizures occurred in 9 of 10 cases with a mean onset of 5.8 years. Convulsive and nonconvulsive status epilepticus were later features (6/10, mean onset 9 years). Tonic (40%) and atonic (30%) seizures also occurred. In 3 cases, an unusual seizure type, the atonic-myoclonic-absence was captured on video. A phenotypic spectrum was identified with 7 cases having moderate to severe intellectual disability and refractory seizures including tonic attacks. Their mean age at onset was 23 months. Three cases had a later age at onset (34 months) with relative preservation of intellect and an initial response to antiepileptic medication. Conclusion: The phenotypic spectrum of CHD2 encephalopathy has distinctive features of myoclonic epilepsy, marked clinical photosensitivity, atonic-myoclonic-absence, and intellectual disability ranging from mild to severe. Recognition of this genetic entity will permit earlier diagnosis and enable the development of targeted therapies.

Original languageEnglish (US)
Pages (from-to)951-958
Number of pages8
JournalNeurology
Volume84
Issue number9
DOIs
StatePublished - Mar 3 2015

ASJC Scopus subject areas

  • Clinical Neurology

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