Poor Outcome for Neonatal-Type Nonketotic Hyperglycinemia Treated With High-Dose Sodium Benzoate and Dextromethorphan

Neonatal-type nonketotic hyperglycinemia treatment remains unsatisfactory, even if started early. A review of six patients who underwent treatment for neonatal-type nonketotic hyperglycinemia in our hospital is presented. All patients were treated with a standardized protocol. Medical histories were retrieved from case notes. All six patients had elevated cerebrospinal fluid plasma glycine levels initially. All but one had received sodium benzoate and dextromethorphan from 1 month of age. All suffered from intractable seizures and severe mental retardation, and only two patients remain alive. One patient died at 5 days of age. No resuscitation was attempted in accordance with the family's wish after genetic counseling. The prognosis of neonatal nonketotic hyperglycinemia remains poor with current treatment. Genetic counseling helps parents cope with this devastating genetic disease. (J Child Neurol 2004;19:39—42).