Atypical presentations of pyridoxine-dependent seizures: a treatable cause of intractable epilepsy in infants.

We report on 3 patients with atypical pyridoxine-dependent seizures. Each had either late onset of convulsions (2 cases) or seizure-free intervals of up to several months' duration in the absence of pyridoxine supplementation. The findings, taken together with those in 9 previously reported cases, indicate that a trial of pyridoxine should be performed in all seizure disorders with onset before 18 months of age, regardless of type.