title: Electroclinical Features of Early-Onset Epileptic Encephalopathies in Congenital Disorders of Glycosylation (CDGs).
abstract: Congenital disorders of glycosylation (CDG) are a constantly growing group of genetic defects of glycoprotein and glycolipid glycan synthesis. CDGs are usually multisystem diseases, and in the majority of patients, there is an important neurological involvement comprising psychomotor disability, hypotonia, ataxia, seizures, stroke-like episodes, and peripheral neuropathy. To assess the incidence, among early-onset epileptic encephalopathies (EOEE), of patients with identified congenital disorders of glycosylation (CDG), we made a review of clinical, electrophysiological, and neuroimaging findings of 27 CDG patients focusing on seizure onset, semiology and frequency, response to antiepileptic drugs (AED), and early epileptic manifestations. Epilepsy was uncommon in PMM2-CDG (11%), while it was a main concern in other rare forms. We describe a series of patients with EOEE and genetically confirmed CDG (ALG3-CDG, ALG6-CDG, DPM2-CDG, ALG1-CDG). Epileptic seizures at onset included myoclonic and clonic fits and focal seizures. With time, patients developed recurrent and intractable seizures principally tonic-clonic seizures, infantile spasms, and myoclonic seizures. Electrophysiological correlates included focal and multifocal epileptic discharges, slowed background rhythm, and generalized epileptic activity including burst suppression pattern and status epilepticus. We propose a diagnostic flowchart for the early diagnosis of CDG in patients presenting with EOEE and suggest to perform serum transferrin IEF (or capillary zone electrophoresis) as a first-line screening in early-onset epilepsy.
authors.affiliation: Department of Clinical and Experimental Medicine, Regional Referral Center for Inborn Errors Metabolism, Pediatric Clinic, University of Catania, via Santa Sofia 78, 95123, Catania, Italy. agafiu@virgilio.it.
authors.forename: Agata
authors.initials: A
authors.lastname: Fiumara
authors.affiliation: Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy.|CNR Institute for Polymers, Composites and Biomaterials IPCB, Catania, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Barone
authors.affiliation: Department of Clinical and Experimental Medicine, Regional Referral Center for Inborn Errors Metabolism, Pediatric Clinic, University of Catania, via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Del Campo
authors.affiliation: Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, The Giannina Gaslini Institute, University of Genoa, Genoa, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Striano
authors.affiliation: Department of Pediatrics, Center for Metabolic Disease, KU Leuven, Leuven, Belgium.
authors.forename: Jaak
authors.initials: J
authors.lastname: Jaeken
keywords: ALG1-CDG; ALG3-CDG; ALG6-CDG; Congenital disorders of glycosylation; DPM2-CDG; Epilepsy