The commonest cause is structural brain abnormality, this may be an acquired brain abnormality, or due to de novo gene abnormalities.
Genetic etiologies include: STXBP1 (10-15% of cases), SLC25A22, CDKL5, ARX, SPTAN1, PCDH19, KCNQ2, SCN2A and others.
Family history of seizures or epilepsy is usually not present. A positive family history should trigger a search for a genetic or metabolic etiology.