Abstracts

Rationale: Rationale: Individuals with 22q11 deletion syndromes show a wide range of phenotypic expression including a high prevalence for seizures and developmental delay. Polymicrogyria also entails developmental delay and seizures but there is little known about the cause of polymicrogyria. There has been speculation of genetic causes but none has been confirmed.Methods: This is a retrospective chart review of 4 patients with epilepsy and 22q11 deletion syndrome. The series includes genetic results, Magnetic Resonance Imaging of the brain findings, epilepsy patterns and response to treatment.Results: All the patients were male, and their ages were 20 months, 6 years, 14 years and 29 years old. They were diagnosed with 22q11 deletion via fluorescence in situ hybridization and chromosomal microarray. The 20 month old had a 1.85Mb pair deletion, the 6 year old a 2.6Mb pair deletion, the 17yr old a 2.91Mb pair deletion, and the 29 year old a 3.1Mb pair deletion. All of them had seizures and developmental delay in motor and language functions. The diagnosis of 22q11 deletion was delayed by over 5 years in three of them. MRI’s of the brain in the 29 yr old showed bilateral polymicrogyria in frontal lobes, anterior parietal lobes and perisylvian area, in the 6 yr old bilateral polymicrogyria in the perisylvian area. The 20 month old had T2 hyperintensities and hippocampal unfolding and the 17 yr old had a normal MRI. The 20 month old had an electroencephalogram (EEG) showing partial seizures that responded to levetiracetam and the 17 yr old had a normal EEG but his clinical picture suggested partial seizures that responded to zonisamide. The 6 year old had generalized tonic clonic and partial seizures, and his EEG showed spike and wave discharges over the vertex region. His seizures partially responded to levetiracetam. The 29 year old’s EEG showed slow background with generalized epileptiform discharges and he had generalized tonic clonic, tonic, myoclonic and partial seizures. This patient failed several medications and a vagus nerve stimulation.Conclusions: Polymicrogyria is a well known finding in patients with 22q11 deletion that leads to epilepsy. In this study we found that larger base pair deletions lead to more extensive polymicrogyria and severe epilepsy. Therefore, findings of developmental delay, epilepsy and polymicrogyria in individuals should increase our index of suspicion for a genetic cause of epilepsy such as a 22q11 syndrome. As this syndrome entails several co-morbidities early recognition and a multi-organ work up is essential.