Heterozygous KCNQ2 pathogenic variants cause a broad phenotypic spectrum of mostly neonatal onset epilepsies; these range from self‐limited familial neonatal epilepsy (SLFNE) to severe sporadic cases of developmental and epileptic encephalopathy (KCNQ2‐DEE) most often caused by de novo missense variants. The gene discussed is KCNQ2; the disease is epilepsy.