Takehiko Inui1, Satoru Kobayashi2, Yuka Ashikari2, Ryo Sato3, Wakaba Endo4, Mitsugu Uematsu3, Hiroshi Oba5, Hirotomo Saitsu6, Naomichi Matsumoto6, Shigeo Kure3, Kazuhiro Haginoya4. 1. Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Miyagi, Japan. Electronic address: inutakejp@yahoo.co.jp. 2. Department of Pediatrics, Nagoya City West Medical Center, Nagoya, Japan. 3. Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan. 4. Department of Pediatric Neurology, Takuto Rehabilitation Center for Children, Sendai, Miyagi, Japan. 5. Department of Radiology, Teikyo University Hospital, Tokyo, Japan. 6. Department of Human Genetics, Yokohama City University, Graduate School of Medicine, Yokohama, Japan.
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.
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 epilepticencephalopathy 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.
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