Epilepsy After Febrile Seizures: Twins Suggest Genetic Influence.

Background: A history of complex febrile seizures can increase the risk of epilepsy, but the role of genetic factors is unclear. This analysis evaluated the relationship between febrile seizures and epilepsy.

Methods: Information on the history of seizures was obtained by a questionnaire from twin pairs in the Mid-Atlantic, Danish, and Norwegian Twin Registries. The information was verified using medical records and detailed clinical and family interviews. The initial study evaluated the genetic epidemiology of febrile seizures in this population. Further information was analyzed and used to evaluate genetic associations of different febrile seizure subtypes.

Results: Histories of febrile seizures were validated in 1051 twins in 900 pairs. The febrile seizure type was classified as simple, complex, or febrile status epilepticus. There were 61% simple, 12% complex, and 7% febrile status epilepticus. There were 78 twins who developed epilepsy. The highest rate of epilepsy (22.2%) occurred in the febrile status epilepticus group. Concordance was highest in simple group.

Conclusion: A twin with febrile status epilepticus is at the highest risk of developing epilepsy, but simple febrile seizures gave the highest risk for the unaffected twin to develop seizures or other neurological issues. These results are consistent with previous findings. There is a subgroup of febrile seizures that can be associated with long-term consequences. This subgroup can be associated with a significant financial and emotional burden. It is currently not possible to accurately identify which children will develop recurrent febrile seizures, epilepsy, or neuropsychological comorbidities.