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The phenotype of SCN8A developmental and epileptic encephalopathy.
- Source :
-
Neurology [Neurology] 2018 Sep 18; Vol. 91 (12), pp. e1112-e1124. Date of Electronic Publication: 2018 Aug 31. - Publication Year :
- 2018
-
Abstract
- Objective: To delineate the electroclinical features of SCN8A infantile developmental and epileptic encephalopathy (EIEE13, OMIM #614558).<br />Methods: Twenty-two patients, aged 19 months to 22 years, underwent electroclinical assessment.<br />Results: Sixteen of 22 patients had mildly delayed development since birth. Drug-resistant epilepsy started at a median age of 4 months, followed by developmental slowing, pyramidal/extrapyramidal signs (22/22), movement disorders (12/22), cortical blindness (17/22), sialorrhea, and severe gastrointestinal symptoms (15/22), worsening during early childhood and plateauing at age 5 to 9 years. Death occurred in 4 children, following extreme neurologic deterioration, at 22 months to 5.5 years. Nonconvulsive status epilepticus recurred in 14 of 22 patients. The most effective antiepileptic drugs were oxcarbazepine, carbamazepine, phenytoin, and benzodiazepines. EEG showed background deterioration, epileptiform abnormalities with a temporo-occipital predominance, and posterior delta/beta activity correlating with visual impairment. Video-EEG documented focal seizures (FS) (22/22), spasm-like episodes (8/22), cortical myoclonus (8/22), and myoclonic absences (1/22). FS typically clustered and were prolonged (<20 minutes) with (1) cyanosis, hypomotor, and vegetative semiology, sometimes unnoticed, followed by (2) tonic-vibratory and (3) (hemi)-clonic manifestations ± evolution to a bilateral tonic-clonic seizure. FS had posterior-temporal/occipital onset, slowly spreading and sometimes migrating between hemispheres. Brain MRI showed progressive parenchymal atrophy and restriction of the optic radiations.<br />Conclusions: SCN8A developmental and epileptic encephalopathy has strikingly consistent electroclinical features, suggesting a global progressive brain dysfunction primarily affecting the temporo-occipital regions. Both uncontrolled epilepsy and developmental compromise contribute to the profound impairment (increasing risk of death) during early childhood, but stabilization occurs in late childhood.<br /> (© 2018 American Academy of Neurology.)
- Subjects :
- Adolescent
Child
Child, Preschool
Developmental Disabilities complications
Developmental Disabilities genetics
Electroencephalography
Female
Humans
Infant
Male
Mutation
NAV1.6 Voltage-Gated Sodium Channel genetics
Spasms, Infantile complications
Spasms, Infantile genetics
Young Adult
Developmental Disabilities diagnosis
Spasms, Infantile diagnosis
Subjects
Details
- Language :
- English
- ISSN :
- 1526-632X
- Volume :
- 91
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Neurology
- Publication Type :
- Academic Journal
- Accession number :
- 30171078
- Full Text :
- https://doi.org/10.1212/WNL.0000000000006199