One of the most severe NDD + E, epilepsy of infancy with migrating focal seizures (EIMFS), is associated with de novo GoF mutations in KCNT1, encoding the sodium‐activated potassium channel subunit KCa4.1 (Barcia et al., 2012; McTague et al., 2018). The gene discussed is KCNT1; the disease is epilepsy.