Self-limited neonatal seizures and familial neonatal epilepsy may have similar clinical and electrical features, but can be distinguished on the basis of family history. These entities may have similar genetic etiologies, with de novo mutations responsible for the lack of family history in self-limited neonatal seizures.
Seizures start in the neonate between day 4 and 7 of life and are often unilateral clonic events that recur and may alternate sides from seizure to seizure. Seizures can be repetitive over hours to days. Seizures remit by 4-6 months of age. A proportion of those affected may have seizures in later life. The child is expected to have normal developmental progress.
These syndromes typically have onset between days 4 and 7 of life. If children are born prematurely, seizures may occur within days of being at term, by corrected age. Seizures remit by 4-6 months of age, the majority ceasing by 6 weeks of age. Both sexes are affected equally. Pregnancy and birth history is unremarkable. Head size and neurological examination are normal. Developmental progress is expected to be normal although minor learning difficulties have been reported in some patients. Studies report an increased risk of febrile and afebrile seizures in later life. Some neonates with KCNQ2 mutations may have myokymia (continuous muscle activity causing stiffness and subtle twitching).
NOTE The neonatal period is defined as the period from birth to 28 days of life.
NOTE Some cases have seizure onset just outside of the neonatal period (in the first 2 months of life), and the syndrome in this case is called self-limited familial neonatal-infantile epilepsy.