Long-term follow-up of an individual with vitamin B6-dependent seizures.

We report on a 31-year-old female with vitamin B6-dependent seizures whose seizure onset was in the neonatal period. Her elder brother had the same disorder and died in infancy. Administration of vitamin B6 was initiated in the postnatal period. At the age of 12 years 1 month, 2 months after withdrawal of vitamin B6, visual seizures began to occur frequently. Myoclonic seizures and occasional generalized convulsive seizures were also observed. At the same time, photoparoxysmal response and spontaneous diffuse spike-wave bursts were seen on her EEG. Myoclonic seizures were provoked by intermittent photic stimulation during the EEG. It is distinctive that visual seizures were one of the main seizure types in this patient, that her clinical course was relatively benign, and that she has normal intellectual outcome.