ESPE Abstracts (2015) 84 P-3-721

GAD Antibodies Negative Type 1 Diabetes and Dravet Syndrome

Sara Cicconea, Romana Marinia, Lucia Fuscob, Alessandra Terraccianoc, Riccardo Schiaffinia & Marco Cappaa

aEndocrinology and Diabetes Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy; bNeurology Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy; cUnit of Molecular Medicine for Neuromuscular and Neurodegenerative Diseases, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy

Background: An association between type 1 diabetes mellitus (T1DM) and idiopathic generalized epilepsy is reported. Some authors suggest an autoimmune mechanism mediated by antibodies to glutamic-acid-decarboxylase (GAD), that is an enzyme involved in the synthesis of the neurotransmitter GABA. Dravet syndrome (DS) is a rare, severe epilepsy disorder characterized by febrile hemiclonic seizures or generalized status epilepticus starting at 6 months of age. In classical DS, a delayed development and a motor impairment are often described. Mutation or deletions of SCN1A account for 85% of DS cases. SCN1a mutations alter sodium channel activity that can predispose the SNC to abnormal excitability.

Objective and hypotheses: To discuss the association of antibodies negative T1DM and DS in a patient.

Method: Case report and literature review.

Results: We report the case of a 9-year-old boy with T1DM and DS. No familial history of epilepsy or diabetes was reported. The patient was a first-born at the 37th week from a normal pregnancy. He presented a normal adaptation at birth. At 8 months, he developed febrile seizures, then at 2.5 years he presented afebrile generalized tonic-clonic seizures. A DS was clinically diagnosed, confirmed by a positive test for a SCN1A gene mutation (heterozygous c.560_563inv).Epilepsy has proved to be drug-resistant (valproate, gardenal, topiramate, levetiracetam and then stiripentol). A mild improvement of seizures was reported with stiripentol treatment. At the age of 7, the boy developed a T1DM. Blood examinations revealed glycaemia 536 mg/dl; glycated haemoglobin 86 mmol/mol (n.v.20–38), venous pH 7.29, bicarbonate 10.7 mmol/l, base excess −17.1 mmol/l; phosphotyrosine antibodies positive, negative anti-GAD and anti-insulin antibodies. The antibody panel was confirmed after 2 years.

Conclusion: A concordance between GAD-antibody titres and clinical manifestations of myoclonic encephalopathy was reported in some patients, in whom a pathogenetic role of GAD autoimmunity was suggested. In the presented case, we can hypothesise an autoimmune aetiology but not GAD-antibodies mediated.

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