ENFL3 is characterised by clusters of motor seizures that occur during sleep. Patients may experience arm flexion, tonic head extension, unintelligible speech, mouth movements and an epileptic aura. EEG studies identify the episodes as partial seizures with an origin in the frontal lobe. The condition can often be misdiagnosed as night terrors, nightmares, hysteria or paroxysmal nocturnal dystonia. ENFL is a rare disorder with less than 100 cases reported worldwide. It often has an onset in childhood, but can begin anytime between infancy and mid-adulthood. It has an incomplete penetrance of 60-80% and varies in severity even between members of a family. The prognosis of the condition is positive as the episodes become milder and less frequent with age.
Diagnosis is made based on 4 criteria: a history of tonic-clonic seizures during sleep, a motor event duration of less than 2 minutes, unstructured vocalization during the episode and an experience of an aura preceding the motor attack. Anti-epileptic drugs have been found to be very effective in controlling seizures.