Efficacy of the KD, with greater than 90% seizure reduction, has been reported in patients with monogenic DEEs, including KCNQ2-DEE (Ko et al., 2018) and Dravet syndrome (Knupp and Wirrell, 2018). Here, KCNQ2 is linked to encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.