Epileptic spasms in congenital disorders of glycosylation
Andreia G Pereira, Nadia Bahi-Buisson, Christine Barnerias, Nathalie Boddaert, Rima Nabbout, Pascale de Lonlay, Anna Kaminska, Monika Eisermann
Epileptic Disorders: International Epilepsy Journal with Videotape 2017 March 14
Congenital disorders of glycosylation (CDG) are a group of rare metabolic diseases, characterized by impaired glycosylation of proteins and lipids. Multisystemic involvement is common and neurological impairment is notably severe and disabling, concerning the central and peripheral nervous system. Epilepsy is frequent, but detailed electroclinical description is rare. We describe, retrospectively, the electroclinical features in five children with CDG syndrome and epileptic spasms. Epileptic spasms were observed in patients with CDG Ik, Ic, Ix, and Ip subtypes, and occurred at an early age, before 6 months in all cases, except one who had spasms that started at 18 months. In this patient, spasms had an unusual aspect; they did not occur in clusters and were immediately preceded by a myoclonus. All but one child also presented rare myoclonias. On EEG, background activity was poorly organized with abundant posterior spike and fast rhythm activity, but without hypsarrhythmia. At the last evaluation (age range: 6-12 years), two patients still presented epileptic spasms and subcortical myoclonias, one showed rare generalized tonic-clonic seizures, and two were seizure-free. CDG disorders are associated with epileptic spasms with particular features, such as absence of hypsarrhythmia, posterior EEG anomalies, and an unusual combination of epileptic spasms with myoclonus. These features, associated with pre-existing developmental delay and subcortical myoclonias, may contribute to the diagnosis of CDG syndrome. [Published with video sequence and supplemental EEG plates on www.epilepticdisorders.com].
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