Neurodevelopmental Outcome and Treatment Efficacy of Benzoate and Dextromethorphan in Siblings with Attenuated Nonketotic Hyperglycinemia

Abstract

Objective To evaluate the impact of sodium benzoate and dextromethorphan treatment on patients with the attenuated form of nonketotic hyperglycinemia. Study design Families were recruited with 2 siblings both affected with attenuated nonketotic hyperglycinemia. Genetic mutations were expressed to identify residual activity. The outcome on developmental progress and seizures was compared between the first child diagnosed and treated late with the second child diagnosed at birth and treated aggressively from the newborn period using dextromethorphan and benzoate at dosing sufficient to normalize plasma glycine levels. Both siblings were evaluated with similar standardized neurodevelopmental me..