Table 3.

SCN3A-Related Neurodevelopmental Disorder and SCN1A-Related Dravet Syndrome

Clinical
Characteristic		SCN3A-NDSCN1A-Related Dravet Syndrome
Age of onset In ~75%, onset in 1st yr of life (mean age of onset in those w/early-onset epilepsy: 2 wks)Age 1-18 mos 1 w/most persons presenting at age 4-12 mos (median age ~5 mos) 2, although a rare, very severe early-onset form has been seen. 3
Temperature
sensitivity 		Febrile seizures have been described in <10% of all persons w/SCN3A-ND. 4Dravet syndrome is defined by temperature-sensitive & febrile seizures.
Infantile spasms
syndrome 		~15% of persons present w/infantile spasms. 5Rare 6
EEG findings Diffuse slowing; slow spike & wave discharges; multifocal or diffuse epileptiform discharges; hypsarrhythmia; burst suppressionAlthough findings vary, initial EEGs are often normal or show mild/nonspecific abnormalities & often evolve to incl generalized spike & wave or polyspike & wave accompanied by multifocal spikes.

From: SCN3A-Related Neurodevelopmental Disorder

Cover of GeneReviews®
GeneReviews® [Internet].
Adam MP, Feldman J, Mirzaa GM, et al., editors.
Seattle (WA): University of Washington, Seattle; 1993-2024.
Copyright © 1993-2024, University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reserved.

GeneReviews® chapters are owned by the University of Washington. Permission is hereby granted to reproduce, distribute, and translate copies of content materials for noncommercial research purposes only, provided that (i) credit for source (http://www.genereviews.org/) and copyright (© 1993-2024 University of Washington) are included with each copy; (ii) a link to the original material is provided whenever the material is published elsewhere on the Web; and (iii) reproducers, distributors, and/or translators comply with the GeneReviews® Copyright Notice and Usage Disclaimer. No further modifications are allowed. For clarity, excerpts of GeneReviews chapters for use in lab reports and clinic notes are a permitted use.

For more information, see the GeneReviews® Copyright Notice and Usage Disclaimer.

For questions regarding permissions or whether a specified use is allowed, contact: ude.wu@tssamda.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.