The possible mechanisms by which VPA may lead to weight gain in epileptic patients are as follows: i) VPA causes leptin resistance by induction, thus, results in patient weight gain (17); ii) single VPA therapy increases the risk of metabolism syndrome in epileptic patients (18); and iii) VPA may cause weight gain by generating insulin resistance, which increases the serum insulin/glucose levels (19). This evidence concerns the gene INS and Insulin resistance.