Authors :
Presenting Author: Heeseung Cho, MD – Severance Children's Hospital, Yonsei University College of Medicine
Seok-jin Lee, MD, PhD – Severance Children's Hospital, Yonsei University College of Medicine
Ara Ko, MD-PhD – Severance Children's Hospital, Yonsei University College of Medicine
Hoon-Chul Kang, MD-PhD – Severance Children's Hospital, Yonsei University College of Medicine
Joon Soo Lee, MD-PhD – Severance Children's Hospital, Yonsei University College of Medicine
Se Hee Kim, MD-PhD – Severance Children's Hospital, Yonsei University College of Medicine
Rationale:
SCN1A-related epilepsies represent a spectrum of epilepsy disorders. These conditions often present with varied clinical features, and recent evidence suggests that the age of seizure onset may further delineate distinct phenotypes. This study aims to investigate the phenotypic differences among SCN1A-related epilepsy patients categorized by the age of seizure onset.
Methods:
This study included patients with pathogenic or likely pathogenic SCN1A mutations treated at Severance Children’s Hospital. Patients were divided into three groups based on the age of seizure onset: Group 1 (early onset, < 3 months), Group 2 (intermediate onset, 3≤ – < 12 months), and Group 3 (late onset, ≥12 months). The prevalence of various seizure types, including febrile seizures, status epilepticus, and hemiclonic seizures, was compared across these groups.
Results:
A total of 174 patients (82 female) with SCN1A mutations were analyzed. The mean age of seizure onset was 3.5 months for Group 1, 6.8 months for Group 2, and 12.2 months for Group 3. The sex distribution across the groups was balanced, with no statistically significant differences (p=0.760). Significant differences were observed in the prevalence of febrile seizures across the groups. Group 2 had the highest percentage of patients with febrile seizures at 98.6%, followed by Group 3 at 91.3%, and Group 1 at 77.8% (p=0.004). The occurrence of status epilepticus also varied significantly between the groups. In Group 2, 40.8% of patients experienced status epilepticus, compared to 4.5% in Group 1 and 4.3% in Group 3 (p=0.002). Hemiclonic seizures were most common in Group 1, with 66.7% of patients affected, compared to 45.8% in Group 2 and 26.1% in Group 3. Although there was a noticeable trend, the difference approached but did not reach statistical significance (p=0.082).
Conclusions:
Patients with seizure onset between 3 and 12 months are more likely to experience febrile seizures and status epilepticus, suggesting a distinct clinical disorder compared to those with earlier or later seizure onset. These findings highlight age of onset as a potential biomarker for categorizing SCN1A-related epilepsies, which could improve clinical management and prognostication.
Funding: none