What to Know About Juvenile Myoclonic Epilepsy
A Brain Disorder With Variable Outcomes
Medically reviewed by Nicholas R. Metrus, MD
Juvenile myoclonic epilepsy (JME) is a seizure disorder that begins during childhood or adolescence. It is sometimes called juvenile myoclonic epilepsy of Janz or Janz syndrome. People with JME experience a few different seizure types, including myoclonic seizures, which are seizures that involve quick, jerking movements of the arms and legs (myoclonic jerks).
If you or your child is diagnosed with myoclonic epilepsy, it's important for you to know that antiepileptic medication can usually help keep the seizures under control. This article covers the effects, causes, and treatments of juvenile myoclonic epilepsy and what you can expect when living with this condition.
JohnnyGreig / Getty Images
Seizure Types in Juvenile Myoclonic Epilepsy (JME)
Living with JME usually means you have several different seizure types. This condition is one of the epilepsy syndromes. This means it is a type of epilepsy that has a group of characteristic features, including seizure types, genetics, triggers, associated symptoms, and certain diagnostic patterns.
Seizure types in JME include:
Myoclonic seizures: A myoclonic seizure in JME typically occurs within a few hours of waking up from sleep. These episodes involve involuntary jerking motions, usually of the arms, with or without a decreased level of awareness.
Generalized tonic-clonic seizures: This type of seizure involves involuntary shaking and jerking of both sides of the body, with unawareness of what is happening. A person may pass out or sleep for minutes or longer after a generalized tonic-clonic seizure. This seizure type may result in physical injuries.
Absence seizures: The episodes are often described as staring spells. Absence seizures include staring into space without interacting or responding. Less often, they involve involuntary face, hand, or mouth movements. Absence seizures typically last for less than 10 seconds at a time, and people can’t remember having them.
In addition to these seizure types, people with JME frequently experience myoclonic jerks that occur even without a seizure. These are repetitive movements of the arm or leg that happen when a person is waking up from sleep.
JME is also associated with an increased risk of learning and language disabilities, neurodevelopmental problems, and mental health disorders.
Related: An Overview of Seizure Phases
What Causes JME?
Usually, juvenile myoclonic epilepsy occurs without a specific cause. Sometimes, this condition is associated with changes in the structure or function of the brain that predispose someone to seizures and other developmental challenges involving speech, learning, and physical skills.
There are no known risk factors that you can avoid to prevent yourself or your child from developing JME.
Avoid Head Trauma
In general, it’s recommended that all people, especially children, avoid head trauma, which can predispose them to epilepsy or worsen existing epilepsy. Measures like wearing helmets during contact sports and bike riding can help prevent brain injuries.
What Can Trigger Seizures in People with JME?
People with JME can have seizures due to the same triggers that could trigger a seizure in anyone with epilepsy. In addition to the usual seizure triggers, other factors can provoke a seizure in people with JME.
In general, if you have type of epilepsy, you may have an increased risk of having a seizure whenever you drink alcohol, skip meals, become dehydrated, don’t get enough sleep, get sick, or don’t take your anti-seizure medication.
People with JME also have the following seizure triggers:
Waking up from sleep
Looking at flashing lights
Stress
While it’s not possible to avoid waking up from sleep, and it’s nearly impossible to completely avoid stress, you can take certain safety precautions if you experience these triggers. For example, avoiding stairs after waking up can help prevent falling and injuries.
It is a good idea to avoid attending movies, concerts, or other performances where flashing lights are part of the show.
Is JME Inherited?
People who have family members with epilepsy or learning disabilities have an increased risk of having juvenile myoclonic epilepsy, but there’s no direct inheritance pattern.
It’s been found that JME has some relationship to genetics, but many people who have this condition don’t have a corresponding gene. It isn’t typical to have a genetic screening test for the genes associated with JME.
Genes associated with JME include GABRA1, GABRD, EFHC1, BRD2, CASR, and ICK. These genes are involved in brain development. Alterations in these genes can affect the structure and function of the brain, potentially leading to epilepsy.
Learn More: Is Epilepsy Genetic?
How Is JME Diagnosed?
If you or your child has had seizures, your healthcare providers will consider epilepsy a possible cause. You or your child will likely need to see a neurologist or a pediatric neurologist during your epilepsy evaluation. The diagnosis of JME involves a medical history, assessment of symptoms, and diagnostic testing.
Usually, features such as the seizure description, age when seizures started, and seizure triggers will guide your neurologist to consider JME as a possible diagnosis. The physical examination of a person with JME is expected to be normal.
Diagnostic tests you may need include:
Blood tests: No blood markers are used to diagnose JME, but blood tests can identify metabolic changes that could cause seizures—with or without a diagnosis of JME.
Urine test: Some metabolic changes can cause altered urine test results. Substances, such as certain medications, alcohol, or drugs, can often trigger a seizure, especially when someone has epilepsy.
Electroencephalogram (EEG): With JME, an EEG may show a pattern described as a 3 Hertz spike and wave pattern that is primarily noted in the occipital cortex, which is the posterior (back) area of the brain.
Brain imaging tests: Brain imaging is usually normal in JME. Some subtle changes can be detected on brain magnetic resonance imaging (MRI) or positron emission tomography (PET) scans, but the presence or absence of such changes doesn’t rule in or rule out JME.
Genetic testing: Genetic tests may help identify some of the genes that are associated with JME. This type of testing would not rule in or rule out the diagnosis. But it would potentially be considered along with other diagnostic results.
Lumbar puncture: This test is invasive and involves the placement of a needle into the lower back to collect cerebrospinal fluid (the fluid that surrounds the brain and spinal cord). It can be used to identify changes that are associated with infections, autoimmune disease, and inflammation.
Your neurologist and other healthcare providers will evaluate all these factors together to determine whether you have epilepsy and what type of epilepsy you might have.
How Is JME Treated?
Treatment of JME relies on antiepileptic medications (AEDs) and lifestyle measures to avoid seizure triggers. Specific AEDs are beneficial for preventing seizures in JME. Certain AEDs are known to worsen the seizure frequency and severity of seizures in JME.
AEDs commonly used to treat JME include:
Lamictal (lamotrigine)
Keppra (levetiracetam)
Zonegran (zonisamide)
Topamax (topiramate)
Depakote (valproate)
Lifestyle measures for reducing seizures in JME include:
Avoid alcohol, smoking, and drugs.
Minimize stress.
Get enough sleep.
Eat healthy meals.
Exercise in moderation.
Avoid flashing lights.
AEDs that are usually avoided in the treatment of JME include:
Tegretol (carbamazepine)
Trileptal (oxcarbazepine)
Dilantin (phenytoin)
What’s the Outlook for People With JME?
The outlook for people with juvenile myoclonic epilepsy varies. The condition can change over a person's lifetime in several ways.
Most people with JME continue to take medication and achieve good seizure control with medication.
Some people outgrow the condition and might not need AED medication during adulthood. If you aren't having seizures and your EEG doesn't indicate a pattern consistent with epilepsy, your neurologist may evaluate your symptoms and work with you to taper your medication.
Others with this condition continue to have seizures despite medication, potentially requiring epilepsy surgery. Additionally, some people with this condition can develop cognitive or physical challenges.
It isn't possible to predict which of these outcomes you or your child will have, but having more severe seizures, having seizures that aren't easily controlled with AED medication, or having a neurodevelopmental condition is associated with a higher likelihood of having seizures for the long term.
Maintaining close follow-up with your neurologist is important so you can have adequate seizure control.
Summary
Juvenile myoclonic epilepsy (JME) is a type of epilepsy that usually begins during adolescence but can sometimes begin during childhood or during adulthood. JME involves several seizure types, with myoclonic seizures being the most common.
Sometimes this type of epilepsy is associated with a family history of epilepsy, neurodevelopmental disorders, genetic changes, or brain structure changes—but it can also occur without any of these associated factors.
Medication is usually effective for controlling and preventing seizures in JME. Some people need to take antiepileptic medication for the long term, while others are able to stop taking treatment if the condition improves over time.
Read the original article on Verywell Health.
