Neglected Atypical Pyridoxine Dependent Seizures

Vitamin B6 (pyridoxine) dependent seizure (PDS) is an autosomal-recessively inherited disorder which starts within a few hours of birth or even earlier, and can cause intrauterine seizures[1,2]. It occurs while the serum level of B6 vitamin is normal. It is the result of a defect in pyridoxine binding to its apoenzyme glutamate decarboxylase which finally leads to reduced concentrations of Gamma-aminobutyric acid (GABA). Low concentration of GABA is related to decreased seizure threshold[3]. The frequency of PDS is unknown and limited cases have been reported worldwide[4]. Some cases from Iran have already been reported too[5]. Typical PDS is diagnosed according to the following criteria described by Baxter: 1) Seizures resistant to traditional antiepileptic treatment 2) Cessation of seizures with pyridoxine administration, 3) Complete seizure control on pyridoxine monotherapy 4) Recurrence of seizures upon pyridoxine withdrawal[6].