Malignant Migrating Partial Epilepsy of Infancy Fast Facts

Malignant migrating partial epilepsy of infancy (MMPEI) is a type of epilepsy that begins during the first six months after birth.

MMPEI is characterized by seizures that increase in frequency over time. In some cases, seizures may be nearly constant for days at a time.

MMPEI causes significant developmental delays and life-threatening complications.

Many children with MMPEI do not survive past early childhood.

United Brain Association

MMPEI causes significant developmental delays and life-threatening complications.

What is Malignant Migrating Partial Epilepsy of Infancy?

Malignant migrating partial epilepsy of infancy (MMPEI) is a rare type of epilepsy that begins in infants before six months. It is also sometimes known as malignant migrating partial seizures of infancy (MMPSI) or malignant migrating focal seizures (MMFSI) of infancy.

Children with MMPEI often appear to develop normally, but developmental delays set in after seizures begin.

Features of MMPEI Seizures

The distinctive features of MMPEI seizures include:

  • Focal seizures begin in one area of the brain.
  • Seizures may affect more than one area of the brain at once or may move from one area to another during an episode.
  • Seizures begin before the age of six months, most commonly within a few weeks after birth.
  • Seizures do not respond well to treatment.
  • Seizures are infrequent at first but increase in frequency as time goes on.

What Causes Malignant Migrating Partial Epilepsy of Infancy?

Scientists don’t yet know the precise cause of MMPEI. Abnormal changes (mutations) in a gene called the KCNT1 gene have been identified in some children with the disorder. Still, it is likely that mutations in other genes may be associated with the condition, as well.

The KCNT1 gene carries instructions for making a protein that plays a role in brain cells’ ability to send electrical signals to one another. Therefore, mutations in the gene could interfere with protein production and, consequently, cause abnormalities in brain cell signaling. However, it’s unclear exactly how this signaling disruption works or why seizures in MMPEI move from one part of the brain to another.

Is Malignant Migrating Partial Epilepsy of Infancy Hereditary?

MMPEI is not thought to be an inherited disorder in most cases. The gene mutations associated with most cases of MMPEI appear to be “de novo” mutations, meaning they occur during early embryonic development and are not passed to the child from their parents. Most children with MMPEI have no family history of the disorder.

How Is Malignant Migrating Partial Epilepsy of Infancy Detected?

The noticeable effects of MMPEI seizures vary depending on which part of the brain is affected, so the disorder may not be easily identifiable at first.

Possible signs of an MMPEI seizure include:

  • Flushing (redness and warmth) in the face
  • Briefly stopping breathing (apnea)
  • Moving the head or eyes to one side
  • Jerking in an arm and/or leg on one side of the body
  • Twitching in eyelids or tongue
  • Drooling

How Is Malignant Migrating Partial Epilepsy of Infancy Diagnosed?

A doctor may suspect MMPEI when a child shows symptoms of seizure activity that match the disorder’s characteristic pattern. Diagnostic steps that may be taken to confirm the diagnose can include:

  • Physical and neurological exams
  • Electroencephalogram (EEG) to measure electrical brain activity
  • Magnetic resonance imaging (MRI). MRI findings are usually normal at first but may show deterioration of brain tissue later in the course of the disorder.
  • Genetic testing to look for gene mutations associated with MMPEI


How Is Malignant Migrating Partial Epilepsy of Infancy Treated?

MMPEI has no cure, and its seizures typically do not respond well to the anti-seizure medications that are effective at treating other forms of epilepsy. However, some other treatment options that may be effective in some cases include:

  • Quinidine in cases with KCNT1 mutations
  • Phenytoin in cases with SCN2A mutations
  • Adrenocorticotrophic hormone
  • Prednisone
  • Ketogenic diet
  • Vagus nerve stimulation

How Does Malignant Migrating Partial Epilepsy of Infancy Progress?

MMPEI seizures typically increase in frequency through the first few months after symptoms begin. As seizures increase in frequency and duration, neurological damage and severe developmental delays usually result.

Impacts of MMPEI may include:

  • Small head size
  • Severe intellectual disability
  • Loss of skills already acquired
  • Muscle weakness and loss of muscle control
  • Failure to develop language skills
  • Gastrointestinal problems

Children with MMPEI often don’t survive early childhood. However, seizures are likely to continue in patients who survive longer, and life expectancy is always shorter than average.

How Is Malignant Migrating Partial Epilepsy of Infancy Prevented?

There is no known way to prevent MMPEI. However, genetic counseling is advised for known carriers of any genetic mutations associated with the disorder. In addition, a genetic counselor can help prospective parents assess their risk if they plan to have children.

Malignant Migrating Partial Epilepsy of Infancy Caregiver Tips

  • Take time to process your feelings after you get a diagnosis of MMPEI. Work through your emotions at your own pace, and don’t feel as if there’s a “normal” time frame that you need to adhere to.
  • Accept help from your family and friends in your caregiving duties. Don’t feel like you have to go it alone or never take a break from caring for your child.
  • Be part of a community. The Epilepsy Foundation provides links to support resources to help you remember that you and your child are not alone in living with epilepsy.

Malignant Migrating Partial Epilepsy of Infancy Brain Science

The KCNT1 gene carries instructions for making a protein that creates a chemical pathway in nerve cells called a sodium channel. Sodium channels are pathways through which sodium atoms can travel from the inside of a cell to the outside, a process that generates an electrical current. This current transmits electrical signals between nerve cells in the brain.

The KCNT1 mutations associated with many cases of MMPEI disrupt the sodium channel so that the electrical current is higher than normal. As a result, nerve cells in the brain become overstimulated, and seizures occur.

Malignant Migrating Partial Epilepsy of Infancy Research

Title: Making Mindfulness Matter© in Children With Epilepsy (M3Epilepsy)

Stage: Recruiting

Principal investigator: Kathy Nixon Speechley, PhD  

Western University

London, Ontario

Epilepsy is a debilitating condition characterized by spontaneous, unprovoked seizures. Up to 80% of children with epilepsy (CWE) may face cognitive, psychiatric, and/or behavioral comorbidities with significant unmet mental health needs. Mindfulness-based interventions may provide an ideal vector to target unmet mental healthcare needs in patients with epilepsy and their families. The investigators propose the Making Mindfulness Matter© (M3) program as an intervention to improve health-related quality of life and mental health for CWE and their parents. M3 is a live-online parent and child program incorporating mindful awareness, social-emotional learning skills, neuroscience, and positive psychology. This pilot RCT is needed to refine the implementation of the intervention to families with a child with epilepsy and collect information about the feasibility and effectiveness of the intervention in preparation for a subsequent multi-centered trial across Canada. Note: Due to COVID-19, the format has been modified for online delivery (from community-based), and the intervention has been restarted.

Mindfulness-based interventions have been increasingly utilized to recognize that medical management for chronic illnesses such as epilepsy does not address the stress and co-occurring psychological issues experienced by many patients. Mindfulness-based interventions are effective, well-validated interventions for several adult outcomes, including physical and mental health, social and emotional well-being, and cognition.


Title: Cannabidiol in Children With Refractory Epileptic Encephalopathy (CARE-E)

Stage: Active

Principal investigator: Richard Huntsman, MD  

University of Saskatchewan

Saskatoon, Saskatchewan

This study will assess the safety and tolerability of a cannabidiol-enriched Cannabis Herbal Extract in a small group of children with refractory epileptic encephalopathy. The dosage of Cannabis Herbal Extract will be gradually increased over four months.

Epileptic Encephalopathies are a group of epilepsies that develop in children. These epilepsies can cause frequent and difficult to control seizures. Because of the ongoing seizures, these epilepsies can also cause cognitive impairment and neurological impairment.

In many children with these Epileptic Encephalopathies, seizures are difficult to control with medical treatment, such as anti-convulsants or non-drug treatments like the ketogenic diet (a high fat, adequate-protein, low-carbohydrate diet). This has resulted in a need to find effective and better-tolerated therapies for children with epileptic encephalopathies.

There is very limited data regarding the use of cannabis products in children, particularly cannabidiol-enriched cannabis oil in children with epilepsy. However, hemp oil products with high cannabidiol and low tetrahydrocannabinol ratios have been reported to provide seizure relief and cognitive improvement in children who take them.

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