CHD2 and epilepsy syndrome: In CHD2 encephalopathy, though published phenotypes can be difficult to interpret, the seizure type of absence seizures with eyelid myoclonia, rather than the epilepsy syndrome, is seen in as many as 8/23 (35%) patients with de novo CHD2 mutation or deletion (Veredice et al., 2009; Dhamija et al., 2011; Capelli et al., 2012; Carvill et al., 2013; Chénier et al., 2014; Lund et al., 2014).