Juvenile myoclonic epilepsy (JME) is a type of epilepsy affecting children and young people. It is a lifelong condition, but treatment can effectively control seizures in most cases.

Symptoms of JME usually begin in adolescence. JME causes myoclonic, generalized tonic-clonic, and absence seizures. These seizures can cause jerking movements, convulsions, or periods of blank staring.

This article looks at the types of seizures and symptoms of JME as well as the causes, diagnosis, treatment, and outlook.

Epilepsy resources

Visit our dedicated hub for more research-backed information and in-depth resources on epilepsy and seizures.

A teenager in a hospital waiting to be tested for juvenile myoclonic epilepsy. -2Share on Pinterest
FatCamera/Getty Images

JME is the most common type of generalized epilepsy. Generalized epilepsy consists of generalized seizures, which affect both sides of the brain and cause impaired consciousness.

Absence seizures and generalized tonic-clonic seizures are both defined as generalized seizures. JME also causes other types of seizures in addition to generalized seizures.

JME is one of the most common types of epilepsy affecting children and adolescents. It accounts for roughly 5% to 10% of all epilepsy cases. Symptoms of JME usually begin at around 12 to 18 years old.

Symptoms of JME usually begin between 12 and 18 years old, most commonly around age 15. Seizures can start earlier or later than this, though, ranging between 5 and 34 years old.

Myoclonic seizures are the main feature of JME. Myoclonic seizures are usually brief and cause jerking movements in the arms and sometimes the legs. If the movements only affect the fingers, they can cause people to drop things or appear clumsy.

Jerking movements often affect both sides of the body, but in roughly 1 in 5 cases, the jerking movements may mostly affect only one side of the body.

Myoclonic seizures usually occur 1 to 2 hours after waking from sleeping or napping. People remain conscious with this type of seizure.

Other types of seizures can occur with JME, which may cause the following symptoms:

  • Generalized tonic-clonic seizures:
    • stiffening of muscles
    • crying out or groaning
    • temporary loss of consciousness
    • jerking of arms and legs
    • breathing difficulty
    • loss of bladder or bowel control
  • Absence seizures:
    • blankly staring into space
    • suddenly stopping activity
    • fluttering eyelids
    • lip smacking or chewing motion
    • small movements of the fingers or hands

Absence seizures are typically very brief and may last for fewer than 10 seconds. People may not be aware of having absence seizures.

Seizure types with JME

Seizure types that occur with JME are:

The main type of seizure with JME is myoclonic seizures. Myoclonic seizures are part of the diagnostic criteria of JME.

Most people with JME will have generalized tonic-clonic seizures, which occur in 85% to 90% of JME cases. Generalized tonic-clonic seizures usually begin a few months after the first myoclonic seizures start.

Around 20% to 40% of people with JME will have absence seizures. These are typically the first type of seizure to occur with JME, usually 3 to 5 years before myoclonic or generalized tonic-clonic seizures first begin.

Seizures can occur unexpectedly and without any specific reason or trigger, but triggers can make seizures more likely.

Common seizure triggers in people with JME include:

Around 30% to 40% of people with JME are photosensitive, which means certain lighting conditions or patterns can trigger seizures. This can include:

  • flashing or flickering lights, such as strobe lighting
  • sunlight, including light shining through trees
  • television
  • computer screens
  • video games
  • light reflecting off water or snow

Learn more about alcohol and seizures.

Genetic mutations can cause JME, but experts are still unclear on the exact inheritance pattern of the genes. The genes linking to JME are:

  • CACNB4
  • EFHC1
  • GABRA1

Sometimes the cause of JME is unknown. Most people with JME have normal results in genetic testing for specific genes linking to epilepsy. In families with JME, around 50% to 60% have a cousin or direct relative who has seizures.

A biological parent can pass on genetic mutations that may cause or increase the chance of a child developing JME.

In some cases, structural changes in the brain may be a potential cause of JME. However, in most standard JME cases, MRI scans of the brain are normal.

To diagnose JME, a doctor will first ask about symptoms to check which type of seizures people are experiencing. They will also take a personal and family medical history. Medical testing for JME includes:

  • physical and neurological tests, which may include tests to check muscle function, reflexes, and mental function
  • electroencephalogram (EEG), a test that measures the electrical activity of the brain and is usually abnormal in people with JME

JME does not show up on an MRI scan. However, during the diagnostic evaluation, doctors usually use brain MRI scans to rule out other causes of seizures, such as a brain tumor or blood vessel malformation.

Lifestyle changes to minimize or avoid exposure to seizure triggers is an important part of managing JME. These can include:

  • getting enough quality sleep and rest to avoid sleep deprivation
  • developing healthy ways to manage emotions and stress
  • avoiding drinking alcohol

Anti-epilepsy drugs are an effective way of controlling JME. The most effective drug for treating JME is valproic acid. It targets all the types of seizures that can occur with JME.

Valproic acid is not suitable with pregnancy, as it can cause birth defects.

Other treatment options for JME include the following antiseizure drugs:

Clonazepam is a sedative that may help control myoclonic jerks.

If JME does not respond to one of the above drugs, combination therapy with two or more medications, possibly alongside vagus nerve stimulation, is another option.

According to the Child Neurology Foundation, people with JME have an excellent outlook. With proper treatment, people may stay seizure-free. Most people are able to live full, independent lives.

There is currently no cure for JME, so people need to manage the condition throughout their life. JME usually improves once a person reaches their 40s.

Medications can help manage JME in most cases and effectively control seizures. If people discontinue medication, there is a high risk of the seizures relapsing.

People may also experience mental health issues as a complication or comorbidity of JME.

Research suggests there may be higher levels of psychiatric disorders in people with JME, including:

However, proper management, including medications and therapy, can help alleviate mental health symptoms. Treating JME may also help resolve mental health issues if JME is an underlying cause of them.

Many organizations and networks can help support people with epilepsy. This can include resources, advocacy, support groups, and helplines.

People may find the following resources helpful:

JME causes generalized seizures. Symptoms usually begin in adolescence. The main type of seizure is myoclonic seizures, but generalized tonic-clonic and absences seizures also occur with JME.

JME occurs due to certain genetic mutations. In people with JME, certain triggers can cause seizures, such as sleep deprivation, stress, and alcohol. Certain lights may also trigger seizures in some people.

JME is a lifelong condition, but in most cases, treatment can effectively allow people to live seizure-free.