OP88 – 2674: Phenotype of children with epilepsy and type 1 diabetes. A case series and study of anti-GAD antibody status

Abstract

Objective Epilepsy and Type 1 Diabetes (T1DM) are conditions that affect significant populations worldwide. Evidence is conflicting and scarce on the hypothesis that there is an increased incidence of epilepsy in T1DM due to an immunological or pathological role of the anti-GAD antibody, given its known association with neurological conditions. Our aim is to study the prevalence of epilepsy in a Paediatric diabetes cohort and identify evidence of a specific epilepsy phenotype, focusing on the significance of serum anti-GAD antibodies. Methods Patients investigated for recurrent seizures were identified using electronic clinical records of T1DM patients in a 2013–2014 tertiary Paediatric Diabetes registry. Data was collected on demographics, seizure type, epilepsy syndrome, EEG, MRI, anti-GAD antibody result, treatment and comorbidities. Patients who had provoked seizures or epilepsy attributable to a known underlying cause were excluded. Data on anti-GAD antibody levels of T1DM patients without epilepsy were also collected. Results 9 out of 364 T1DM patients were investigated for recurrent seizures. Excluding 3 with nonepileptic diagnoses and 1 with mitochondrial cytopathy, 5 (1.37%) had an epilepsy syndrome identified: 2 had Juvenile Myoclonic Epilepsy, 2 temporal lobe epilepsy and 1 multifocal epilepsy. None of the patients were treatment resistant, 2 had other autoimmune conditions. Anti-GAD antibodies levels were available in 4 out of the 5 patients, of which 2 patients were positive, but none were >1000u/mL. Conversely, in the 171 patients without epilepsy in whom anti-GAD results were available, 132 (77%) were positive, and 20 (11%) had results of >1000u/mL. Conclusion The prevalence of epilepsy (1.37%) in our TIDM cohort is higher than the reported prevalence in the general paediatric population of 0.4%. Children in our cohort with epilepsy and TIDM do not appear to exhibit a specific epilepsy phenotype, nor do they appear to have a higher one-off measurement of anti-GAD antibody.