Juvenile Myoclonic Epilepsy


Epilepsy is a group of disorders that cause seizures. Seizures are involuntary episodes that may affect muscle control, movement, speech, vision and awareness. Epilepsy is caused by sudden, intense bursts of electrical activity in the brain.

Juvenile Myoclonic Epilepsy is one of many different types of epilepsy. Its most common symptom is repeated seizures, known as myoclonic seizures. These cause quick jerking movements.

It's also sometimes called Janz syndrome or Epilepsy of Janz.


Juvenile myoclonic epilepsy often begins in teenage years with myoclonic seizures, which are often very short. People with this form of epilepsy often go on to have more severe seizures, known as grand mal seizures, in adulthood. These seizures are longer, cause the person to stridden and fall to the ground, and for the limbs jerk in strong, rhythmic movements. They may also lose consciousness and lose control of body functions.

Juvenile myoclonic seizures generally affect the neck, shoulders and upper arms.

Myoclonic seizures may go unnoticed because they happen so quickly. Someone may think they are tics or clumsiness. Symptoms of these seizures include:

  • Quick, uncontrolled muscle jerks
  • Jerky or rhythmic movements

Grand mal seizures are also known as tonic-clonic seizures. These seizures occur in two stages.

  • Tonic - The patient's muscles will stiffen and they will lose consciousness. This will cause them to fall to the ground. The muscles of the body tighten and it often becomes difficult to breath. The lips may turn a blue color. The patient may make gurgling sounds. This stage lasts a minute or less.
  • Clonic - The muscles begin to jerk. This is caused by the muscles flexing and relaxing very quickly many times. The jerking movements will begin to slow down and happen less often as the seizure progresses. Eventually the jerking movements will stop completely. This stage usually lasts a few minutes.

Causes and Risk Factors

There is often no known cause of epilepsy. A family history of epilepsy may sometimes be linked to the condition. However, experts are not sure how the disease is passed from parent to child.

Changes in the GABRA1 gene have been linked to the condition.


Making a correct epilepsy diagnosis is important. The doctor will ask you questions about your seizures to determine the type and if they are caused by epilepsy.

A detailed medical history often has the best clues about seizures. It may help rule out other conditions that might have caused the seizures. Patients will also have a neurological exam. During the exam they will be asked to recall what happens just before, during and right after they experience seizure.

The most useful way to diagnose epilepsy is an electroencephalogram (EEG). This records electrical activity in the brain. The EEG can record unusual spikes or waves in electrical activity patterns. Different types of epilepsy can be identified with these patterns.

Magnetic resonance imaging (MRI) and computed tomography (CT) scans may be used to look at the cause and the location within the brain. The scans can show scar tissue, tumors or structural problems in the brain.


Partial and generalized seizures caused by Juvenile Myoclonic Epilepsy are often treated differently.

Treatment is based on:

  • The type of seizure
  • How often seizures happen
  • How severe the seizures are
  • The patient's age
  • The patient's overall health
  • The patient's medical history

Medications commonly used include:

  • Levetiracetam
  • Depakote
  • Clobazam
  • Zonegram, for cases that have not been responsive to other treatments

Anti-seizure (or anti-epileptic) medications can be very helpful. Finding the right medication and the right dosage sometimes takes a few tries. Your doctor will work with you to watch for side effects and find the best treatment.

Vagus Nerve Stimulation (VNS) implantation surgery may be an option if medication can't control the seizures.

© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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