Juvenile myoclonic epilepsy mimic associated with CHD2 gene mutation

Abstract

This paper reports the electroclinical manifestations of an epilepsy syndrome associated with a chromodomain helicase DNA-binding protein 2 (CHD2) gene mutation with clinical semiology and electroencephalographic (EEG) features consistent with juvenile myoclonic epilepsy (JME). Myoclonic and myoclonic-tonic-clonic seizures, as well as generalized 4- to 5-Hz high-amplitude spike-wave and polyspike-wave discharges, were well characterized in an adolescent. However, the atypical age of onset, developmental disability, and apparent drug resistance led to suspicion of an alternative etiology for epilepsy, subsequently verified as a CHD2 gene mutation. When atypical features are present, a JME mimic should be suspected in the differential diagnosis of the more established syndrome of JME.

Keywords: Autism spectrum disorder; CHD2; CHD2, chromodomain helicase DNA-binding protein 2; CLCN2, chloride channel protein 2; ED, emergency department; EEG, electroencephalogram; EFHC1, EF-hand domain containing protein 1; GABRA1, gamma-aminobutyric acid type A receptor alpha 1 subunit; JME; JME, juvenile myoclonic epilepsy; Juvenile myoclonic epilepsy; TIGER, the Investigation of Genetic Exome Research; WES, whole exome sequencing.