A novel KCNT1 mutation in a Japanese patient with epilepsy of infancy with migrating focal seizures.

Epilepsy of infancy with migrating focal seizures (EIFMS) is a rare, early-onset epileptic encephalopathy characterized by polymorphous focal seizures. De novo mutations of KCNT1 have been identified in cases of this disorder. We encountered a sporadic patient with EIFMS, who suffered tonic convulsions at the age of 9 days. Using Sanger sequencing, we identified a de novo missense mutation of the same amino acid affected by a previously identified mutation, c.1420C>T (p.Arg474Cys).