A 3-month-old boy with early myoclonic epilepsy owing to nonketotic hyperglycinemia developed acute encephalopathy after - vigabatrin was presented. Due to the use of vigabatrin, the elevated gamma-aminobutyric acid (GABA) concentration in the brain together with the elevated levels of glycine enhanced the encephalopathy. Our observations indicate the risk of using vigabatrin in patients with nonketotic hyperglycinemia
