A novel inherited mutation in the voltage sensor region of SCN1A is associated with Panayiotopoulos syndrome in siblings and generalized epilepsy with febrile seizures plus.

We report 2 families harboring a novel SCN1A mutation, one of whom had Panayiotopoulos syndrome and the other a phenotype consistent with generalized epilepsy with febrile seizures plus. Two siblings had recurrent episodes of autonomic status epilepticus with focal features consistent with the diagnosis of Panayiotopoulos syndrome. Both have the SCN1A mutation p.Phe218Leu. The mutation was present in their father who has never had a seizure. The same mutation was identified in a child diagnosed with intractable childhood epilepsy with generalized tonic clonic seizures. From the age of 5, he developed complex focal seizures associated with left hippocampal sclerosis. The mutation was present in his mother, aged 25, who had febrile seizures and developed generalized tonic clonic seizures and his sister who had 1 febrile seizure. Our findings suggest that SCN1A mutations may cause susceptibility to an idiopathic focal epilepsy phenotype, the final phenotype depending on other (genetic or nongenetic) factors.