• Age of onset is 1 to 12 years of age (average 7 years of age).
  • It affects boys more than girls.
  • Seizures are characterized by abrupt onset of staring and unresponsiveness (absence seizure) accompanied by myoclonic (body) jerks of the arms and/or legs.
  • Seizures typically last 10 to 60 seconds.
  • More than 75% of people will have other associated seizure types, such as generalized tonic-clonic, typical absence seizures, and atonic seizures.
  • More than half of people have some degree of learning disability and behavior problems before epilepsy onset, but eventually 70% will develop learning disabilities.
  • Over half of the cases the seizures will persist into adulthood, whereas others may disappear after a mean period of 5.5 years from onset.

What is the syndrome Epilepsy with Myoclonic-Absences?

The syndrome of Epilepsy with myoclonic-absences is a rare form of epilepsy. The typical age of onset is between 2 and 2 years of age with an average of 7 years of age. It is seen more frequently in boys than in girls. The cause of this epilepsy syndrome is unknown. 

Seizures are characterized by abrupt onset of staring and unresponsiveness (absence seizure) accompanied by myoclonic (body) jerks of the arms and/or legs that generally last 10 to 60 seconds. Other seizure types may be seen in more than 75% of people, including generalized tonic-clonic, atonic, and typical absence seizures.

More than half of the patients have learning disabilities and behavioral problems before the onset of the epilepsy, but eventually 70% will develop learning disabilities. This epilepsy syndrome tends to be refractory to treatment and over half of the patients the seizures will persist into adulthood.

What do the seizures in Epilepsy with Myoclonic-Absences look like?

The seizures in Epilepsy with Myoclonic-Absences are characterized by an abrupt onset of staring and unresponsiveness (absence seizure) accompanied by myoclonic (body) jerks of the arms and/or legs that generally last 10 to 60 seconds. The seizures are very frequent, occurring multiple days a day. Other seizure types may be seen in more than 75% of people, including generalized tonic-clonic, atonic, and typical absence seizures. Twitching of the mouth (perioral myoclonia) is frequently seen in people with this epilepsy syndrome.

Is Epilepsy with Myoclonic-Absences inherited?

The cause of this epilepsy syndrome is unknown. It has been reported that approximately 25% of children with this condition will have a family member with a form of epilepsy, usually generalized epilepsy.

How is the syndrome Epilepsy with Myoclonic-Absences diagnosed?

Your doctor will take a good history and may hyperventilate your child during the examination. The EEG is the most important test and will help in making the diagnosis of Epilepsy with Myoclonic-Absences. MRI scans are usually normal, but it is required to exclude a brain abnormality. 

How is Epilepsy with Myoclonic-Absences treated?

Seizures in children with Epilepsy with Myoclonic-absences are frequent and occur multiple times a day. Seizures tend to be resistant to anti-seizure medication

  • Medications often tried are valproic acid (Depakote/Depakene), ethosuximide (Zarontin), lamotrigine (Lamictal), clobazam (Onfi), amongst others. Medications are typically used in combination.
  • Surgery is not usually an option.

What is the outlook for persons with Epilepsy with Myoclonic-Absences?

  • Approximately 70% of people with Epilepsy with Myoclonic-Absences will eventually be diagnosed with learning disabilities. 
  • For more than half of the cases, seizures will persist into adulthood, whereas others may disappear after a mean period of 5.5 years from onset.
  • Prognosis is more favorable if medication can control the seizures.
Authored by: Angel W. Hernandez MD | Pediatrics Editor on 5/2015