Pyridoxine-dependent epilepsy in two Turkish patients in Turkey and review of the literature.

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive enzyme defect in the vitamin B6 metabolism characterized by intractable seizures which are usually resistant to all antiepileptic drugs but respond to pharmacological doses of pyridoxine. We present the clinical and molecular genetic findings of two patients with c.1597_1597delG mutations in ALDH7A1 gene. There are different clinical phenotypes in PDE: patients with complete seizure control with pyridoxine and normal development (group 1), patients with complete seizure control with pyridoxine and development delay (group 2), and patients with persistent seizures despite pyridoxine treatment and with development delay (group 3). Our two patients have persistant seizure despite pyridoxine treatment and with development delay. Pyridoxine-dependent epilepsy can be identified in any neonate with signs of encephalopathy and refractory seizures, with no evidence of hypoxic-ischemic damage or other underlying metabolic disturbance. Neurodevelopmental outcomes of patients with PDE is multifactorial; early diagnosis and treatment of these patients is vital.