Seizures in Angelman Syndrome: A Comprehensive Overview

Quick Overview

Seizures are common in Angelman Syndrome, manifesting as focal or generalised seizures. EEG findings often reveal specific patterns aiding diagnosis. Non-epileptic myoclonus, characterised by twitching movements, can be treated with medication. Seizure treatment options include medications like Depakote, Klonopin, and Phenobarbital, dietary therapy, and surgical options. Newer medications like Onfi, Fycompa, and Briviact show promise, with fewer side effects than traditional drugs. Diet therapy, such as the ketogenic diet, can be as effective as medication. Other treatments include medical marijuana and vagal nerve stimulation. Managing seizure triggers is crucial, and precautions should be taken with certain medications and procedures. Further research is needed to explore the potential benefits of medical marijuana in treating seizures in Angelman Syndrome.


Seizures are a common occurrence in individuals with Angelman Syndrome, primarily affecting the nervous system. In this talk, we will explore the various aspects of seizures in Angelman Syndrome, including seizure types, classification, EEG findings, and treatment options.

Seizure Types and Classification

Seizures in Angelman Syndrome can manifest as focal seizures or generalized seizures. Epilepsy, defined as two or more unprovoked seizures, can be classified into different epilepsy syndromes based on EEG findings and cognitive functioning. Lennox-Gastaut syndrome and myoclonic status are two epilepsy syndromes associated with Angelman Syndrome.

EEG Findings

EEG findings in Angelman Syndrome often reveal spike and wave patterns and notch patterns, which aid in the diagnosis and classification of seizures.

Non-Epileptic Myoclonus

Non-epileptic myoclonus is a condition characterized by twitching movements that are not seizures. It can be treated with medications that improve the quality of life for individuals with Angelman Syndrome.

Treatment Options

Seizure treatment options for Angelman Syndrome include medications, dietary therapy, and surgical options. Commonly used seizure medications in Angelman Syndrome include Depakote, Klonopin, and Phenobarbital. Broad-spectrum seizure medications are typically used to treat generalized epilepsy in Angelman Syndrome. However, non-broad-spectrum seizure medications such as Tegretol and Dilantin can worsen certain seizure types in Angelman Syndrome.

Medications and Side Effects

Newer seizure medications like Onfi, Fycompa, and Briviact show promise in treating seizures in Angelman Syndrome. Keppra, Lamictal, and Onfi have been found to be as effective as Depakote in treating seizures, but with fewer side effects. Keppra may cause irritability and anger in about 20% of patients, while Clobazam can cause sleepiness in about a third of patients. Depakote, on the other hand, can lead to a decline in motor skills in some patients with Angelman Syndrome.

Dietary Therapy

Diet therapy, such as the ketogenic diet, has been found to be as effective as medication in treating seizures in Angelman Syndrome. The ketogenic diet is high in fat and low in carbohydrates, while the low-glycemic diet allows for more carbohydrates. The ketogenic diet is more effective in reducing seizures, but the low-glycemic diet is easier to follow and has almost as good efficacy. During times of illness, the ketogenic diet may worsen, but adding as-needed medication like Valium can help manage breakthrough seizures.

Other Treatment Options

Medications like Keppra, Clobazam, and Briviact have shown effectiveness in treating myoclonus in Angelman Syndrome. Medical marijuana, specifically CBD oil, may also be effective in treating seizures, but further research is needed. Surgical options like resective therapy are generally not recommended for Angelman Syndrome, but the vagal nerve stimulator can be used as a last resort. Non-convulsive status can be treated with medications like Valium and Prednisone.

Managing Seizure Triggers

Addressing and managing seizure triggers such as anxiety, illness, and lack of sleep are crucial in the overall management of seizures in Angelman Syndrome.

Considerations and Precautions

Depakote should be avoided in Angelman Syndrome due to its side effects. However, if an individual is already on Depakote and responding well, it can be continued. Anesthesia and surgery do not typically pose a significant risk for seizures in Angelman Syndrome, but caution should be exercised, and recovery should be closely monitored. Glucose should be avoided in IV fluids for patients on dietary therapy.


In conclusion, a combination of medication, diet therapy, and surgery can effectively manage seizures in Angelman Syndrome. The choice between the ketogenic diet and the low-glycemic diet depends on the severity of seizures and individual patient needs. Further research is needed to explore the potential benefits of medical marijuana in treating seizures in Angelman Syndrome.

Talk details

  • Title: Seizures in Angelman Syndrome
  • Author(s): Ron Thibert
  • Author(s)’ affiliation: Massachusetts General Hospital
  • Publication date: 2017-08-14
  • Collection: 2017 ASF Family Conference