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 | 0 - 6 Months | |
| Developmental Delay Onset | 0 - 6 Months | |
| Seizure Types | Focal, Generalized, Infantile Spasms | |
| Clinical Features | Limited Mobility, Cognitive Function, and Functional Vision; Non-Verbal; Cannot Eat by Mouth | |
| Seizure Freedom | Rarely/Never | |
| Prognosis | Limited Change to Deterioration |
Seizure Onset
0 – 6 Months
Developmental Delay Onset
0 – 6 Months
Seizure Types
Focal, Generalized, Infantile Spasms
Clinical Features
Limited Mobility, Cognitive Function, and Functional Vision; Non-Verbal; Cannot Eat by Mouth
Seizure Freedom
Rarely/Never
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 |
Clincal Features
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.
Seizure Types
There was strong consensus among clinicians regarding the presence of GMS, IS, GTCS, GTS, and Focal Seizures among the Severe DEE phenotype.
Prognosis
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.
Rescue Medications
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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.