Abstracts

Rationale: Self-limited (familial) infantile epilepsy (SeLIE), formerly called benign familial infantile seizure, is an epilepsy syndrome, occurring seizures in normally developing infants. PRRT2 is the most common genetic etiology of SeLIE. In clinical aspect, it is difficult to assume PRRT2-related epilepsy at initial presentation and decide administration of sodium-channel blockers, because of a possibility of seizure aggravation in case of other infantile epilepsy syndrome. Also, it takes a few months to get the genetic result of patients. This study aimed to delineate clinical characteristics of PRRT2-related epilepsy focused for differentiating from other infantile epilepsy syndromes.

Methods: We investigated 32 pediatric patients diagnosed with SeLIE having causative variants of PRRT2 gene visited in two tertiary pediatric epilepsy centers. Medical records were reviewed retrospectively, including initial presentation of seizure, administration of antiseizure medications, electroencephalogram (EEG), brain magnetic resonance imaging (MRI), PRRT2 variants, development, and family history.

Results: Mean onset age of seizure was of 4.0 ± 2.0 months old and two patients had neonatal onset seizure. Familial cases were 20 (62.5%); history of epilepsy in 14, paroxysmal movement disorder in 3, and both in 4 cases. Initial EEG was normal in 29 (90.6%) patients and showed focal epileptiform discharges in 3 patients (9.4%). All brain MRIs performed in 29 patients were normal except one having perinatal cerebral infarction in left frontal lobe. Initial seizure was all afebrile and most cases were bilateral motor seizure (n=23, 71.9%). Four patients had just one seizure (12%) and 28 patients (88%) had recurred seizures before 1 year old. 23 patients of those showed self-limited course by 3 years of age. After 3 years of age, there were three patients that has been treated with antiseizure medications for recurrent seizures. All 18 patients treated with sodium-channel blockers showed good response except one who stopped taking carbamazepine due to skin rash. Valproic acid was followed by a good effect for seizure control in nine patients.

Conclusions: The patients with PRRT2-related epilepsy had their first seizure in relatively early infantile period. They showed distinctive features, including afebrile, bilateral motor seizure, short duration, and clustered seizures at initial presentation. Approximately one-third of patients has de novo variant without a family history. PRRT2-related epilepsy are not always self-limited and some patients may have persistent epilepsy. Understanding these clinical characteristics can be helpful for early diagnosis and effective treatment of them.

Funding: None