Abstracts

Rationale: To describe the seizure types and electrographic patterns of a cohort of south Indian children with genetically confirmed Angelman syndrome. Methods: The clinical records of the children who had presented with global developmental delay, seizures, autistic features or delayed speech to the pediatric neurology clinic in the study period (2006-2013) were reviewed. Those with genetically confirmed Angelman syndrome by DNA methylation study were identified. The clinical features and data of the EEG monitoring were reviewed systematically. Results: 18 children had genetically confirmed Angelman syndrome during the study period. The age at clinical diagnosis ranged from 8 months to 12 years (median 2 years).Follow up period ranged from 1 month to 7 years. Severe developmental delay, absence of expressive speech, microcephaly, facial dysmorphism and fair complexion were present in all the patients. All the patients except 3 had seizures at the time of presentation. The predominant seizure type was generalized myoclonic jerks followed by generalized tonic clonic seizures. 5 children had their initial episode of GTCS with a febrile illness. 2 children developed prolonged nonconvulsive status during follow up. 12 children received antiepileptic drugs. The seizures were fairly responsive to medications and only 3 children received poly therapy. Clobazam was the most frequent medication used singly or in combination. EEG findings were abnormal in all the cases with generalized high amplitude delta waves being the commonest abnormality. The classical frontally dominant notched delta waves were seen in 7 children. The spike and waves were seen mostly in the occipital regions (9 children). Follow up EEGs were available for 6 children. All of them showed significant evolution compared to the baseline EEG. The presence of very high amplitude frontally dominant delta waves was the EEG marker of encephalopathy for the 2 children who developed prolonged nonconvulsive status. Conclusions: Angelman syndrome is a non-progressive encephalopathy which might show characteristically dynamic electrographic patterns, probably depending on the clinical status of the patient and the intake of medications