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Severe DEE

Learn about Severe Developmental & Epileptic Encephalopathy (DEE). One of the five known phenotypes,
Severe DEE is where we find those most profoundly affected by SCN8A-related disorders.

Severe Developmental & Epileptic Encephalopathy

Severe DEE is a serious disorder that begins in infancy. It causes frequent, difficult-to-control seizures and significant delays in a child’s development.  As children get older, they often experience problems with movement, speaking, eating, and other bodily functions. Sadly, Severe DEE can shorten a child’s lifespan and puts them at high risk for SUDEP.

Seizure Onset Seizure Onset 0 - 6 Months
Developmental Delay Onset Developmental Delay Onset 0 - 6 Months
Seizure Type Seizure Types Focal, Generalized, Infantile Spasms
Clinical Features Clinical Features Limited Mobility, Cognitive Function, and Functional Vision; Non-Verbal; Cannot Eat by Mouth
Seizure Freedom Seizure Freedom Rarely/Never
SCN8A Prognosis Prognosis Limited Change to Deterioration
Seizure Onset

Seizure Onset

0 – 6 Months

Developmental Delay Onset

Developmental Delay Onset

0 – 6 Months

Seizure Type

Seizure Types

Focal, Generalized, Infantile Spasms

Clinical Features

Clinical Features

Limited Mobility, Cognitive Function, and Functional Vision; Non-Verbal; Cannot Eat by Mouth

Seizure Freedom

Seizure Freedom

Rarely/Never

Prognosis

Prognosis

Limited Change to Deterioration 

Treatment

Optimal first-line medications

Oxcarbazepine, Carbamazepine

Medications to be cautious of

Levitracitacitam

Important considerations

Gain-of-function (GOF) variants are more common, so sodium channel blockers are preferred. Levetiracetam may worsen seizures and is generally avoided in patients with GOF variants. Ketogenic diet can be helpful

Rescue Medication

IV phenytoin or phenytoin are recommended for status epilepticus

This table shows consensus levels for severity and expected change over time among common comorbidities. Out of all the clinical features listed on the left, all were severe except for autonomic dysfunction and orthopedic issues. None of these are expected to improve over time, but many have the potential for some mixed improvement and stability.

There was strong consensus among clinicians regarding the presence of GMS, IS, GTCS, GTS, and Focal Seizures among the Severe DEE phenotype.

For severe DEE, epilepsy is the only area with possible improvement, and the only area with no consensus between the three listed here. There is moderate consensus that cognition and development expectations range from significant deterioration to limited change.

Keep Exploring 

IMPORTANT: While this consensus data provides new and valuable insights about best practices in the diagnosis and treatment of SCN8A, this is not medical advice. It can inform clinicians and caregivers alike in developing optimal treatment plans for each individual.

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