GLYCOSYLATION DEFECTS AND EPILEPSY

Investigation for inherited metabolic diseases are rarely performed in epileptic children. Usually these patients are classified on the basis of the seizures phenotype and drug response. Seizures are described in Congenital Disorders of Glycosylation (CDG). In the past years (2005-2011) we analyzed more than three thousand samples from Italian patients by transferrin IEF, positive ones were typed by MALDI-TOF. We identified 21 patients with PMM2-CDG (CDG Ia) and seven with different types of non-PMM2 CDG. Among these, drug resistant epilepsy in the first year of life was the presenting sign in six, commonly infantile spasms, myoclonic or tonic-clonic seizures. Dysmorphisms were a constant finding (7/7), followed by microcephaly (6/7), severe mental retardation (6/ 7), visual impairment (5/7) and only 1/7 had cerebellar atrophy. Serum transferrin IEF and MALDI-TOF defined a type I underglycoslation profile in these patients but PMM2 was normal. Definitive diagnosis was ALG6- CDG Ic; ALG3-CDG Id and DPM2 in one patient respectively and is pending in four (CDG Ix). We wish to underline that early onset epileptic encephalopathies and drugresistant epilepsy, in the first months of life, should arouse the suspicion of non PMM2-CDG. This could allow the recognition of a number of undiagnosed CDG cases.