Two cases of early-onset myoclonic seizures with continuous parietal delta activity caused by EEF1A2 mutations.

Abstract

BACKGROUND:

Mutations in the elongation factor 1 alpha 2 (EEF1A2) gene have recently been shown to cause severe intellectual disability with early-onset epilepsy. The specific manifestations of mutations in this gene remain unknown.

CASE REPORT:

We report two cases of severe intellectual disability accompanied by early-onset epilepsy with continuous delta activity evident on electroencephalography. Both cases presented with developmental delay and repetitive myoclonic seizures in early infancy. Both cases showed continuous high-voltage delta activity over both parietal areas when awake, as revealed by interictal electroencephalograms. After the emergence of continuous delta activity, development stagnated. One case showed some development after relief of the seizures and epileptic activity, but drug resistant seizures recurred, and the development again became stagnant. In both cases, a de novo recurrent heterozygous mutation in EEF1A2 [c.364G>A (p.E122K)] was identified by whole-exome sequencing.

CONCLUSION:

This report provides clinical data on epileptic encephalopathy in patients with EEF1A2 mutation. Continuous high-voltage delta activity seen over both parietal areas may be a unique manifestation of EEF1A2 mutation. Epileptic activity may aggravate the effect of the mutation on brain development.

• Authors: Takehiko Inui, Satoru Kobayashi, Yuka Ashikari, Ryo Sato, Wakaba Endo, Mitsugu Uematsu, Hiroshi Oba, Hirotomo Saitsu, Naomichi Matsumoto, Shigeo Kure, Kazuhiro Haginoya
• Journal: Brain & development (Brain Dev) Vol. 38 Issue 5 Pg. 520-4 (May 2016) ISSN: 1872-7131 [Electronic] Netherlands
• PMID: 26682508 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Chemical References

• EEF1A2 protein, human
• Peptide Elongation Factor 1

Topics

• Child, Preschool
• Electroencephalography (methods)
• Epilepsies, Myoclonic (complications, genetics)
• Epilepsy (complications, genetics)
• Female
• Humans
• Intellectual Disability (complications)
• Male
• Mutation, Missense
• Parietal Lobe (physiopathology)
• Peptide Elongation Factor 1 (genetics, metabolism, physiology)
• Phenotype
• Seizures (complications)