This epilepsy syndrome is uncommon. Myoclonic seizures are the only seizure type seen at onset, although infrequent febrile seizures may also occur. Myoclonic seizures may be activated by photic stimulation in some patients, others may have myoclonic seizures that are induced by sudden noise or touch. Cognitive, behavioral and motor difficulties may exist. Seizures are self-limiting, ceasing within 6 months to 5 years from onset. Generalized tonic-clonic seizures may be seen in later life.
NOTE Self-limiting refers to seizures having a high likelihood of spontaneously remitting at a predictable age.
This syndrome is characterized by the onset of myoclonic seizures between the ages of 6 months and 2 years, in some cases earlier (4 months) or later (2-4 years) onset has been reported. Myoclonic seizures may be induced by photic stimulation in some patients, or by sudden noise or touch in others. Infrequent febrile seizures may be seen in approximately 10% of patients. Seizures remit within 6 months to 5 years from onset but generalized tonic-clonic seizures may be seen in teenage years in 10-20% of patients. Patients with photosensitivity may have seizures that are more difficult to control. Males are twice as likely to be affected as females. Antecedent and birth history is unremarkable. Head size and neurological examination are normal. Cognitive, motor and behavioral difficulties are reported, especially if seizures are not controlled.