GRIN2A and ethylmalonic encephalopathy: Previously, GRIN2A mutations were found to be mainly associated with idiopathic focal epilepsy with incomplete penetrance (Carvill et al., 2013; Lemke et al., 2013; Lesca et al., 2013) and occasionally with epileptic encephalopathy (EE) (Venkateswaran et al., 2014; Yuan et al., 2014).