Genetic Testing has taken out Guesswork: Cases of Familial and Non-familial Benign Infantile Epilepsy Associated with PRRT2 gene mutations. (P2.289)

Objective: We report two cases of benign infantile epilepsy (one familial and one non-familial) with mutations in PRRT2 . Background: PRRT2 mutations are known to be associated with both familial and non-familial benign infantile epilepsy, conditions where afflicted infants typically present with clusters of seizures that are self-limited and usually have benign neurodevelopmental outcome. Genetic studies of clinically suspected cases are useful in confirming diagnosis and aid in management of such patients. Design/Methods: In this presentation we describe two cases of infants presenting with clusters of seizures, one with family history of infantile seizures, and the other without family history. Results: Case 1 is a 4 month old girl who presented with clusters of unprovoked seizures. The seizures were refractory to levetiracetam and responded to fosphenytoin. The patient had an older sister with history of self-limited infantile seizures. Birth history and development was normal. MRI of the brain was normal. Routine EEG was abnormal for focal slowing. The genetic study found pathogenic mutation in the PRRT2 , confirming diagnosis of familial benign infantile epilepsy. Case 2 is a 6 month old boy who presented with a cluster of unprovoked seizures. The seizures were refractory to levetiracetam, thus carbamazepine was added to the regimen. The patient did not have family history of seizures. Birth and developmental history was normal. MRI of the brain was normal. EEG showed focal spikes and a focal onset electrographic seizure. The genetic studies were positive for pathogenic mutation in the PRRT2 , leading to diagnosis of non-familial benign infantile epilepsy. Conclusions: We described two cases of benign infantile epilepsy with mutations in PRRT2 . While one case had family history of self-limited infantile seizures which helped in diagnosis, the other case did not have family history. In both cases, genetic testing played a significant role in diagnosis, management and prognostication. Disclosure: Dr. Hisamoto has nothing to disclose. Dr. Verma has nothing to disclose. Dr. Cracco has nothing to disclose. Dr. Giridharan has nothing to disclose.