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.