DEXTROMETHORPHAN THERAPY IN NONKETOTIC HY PERGLYCINEMIA - 4 CASE-HISTORIES

Patients: We report on four infants with nonketotic hyperglycinemia, t hree with a neonatal form and one with the milder infantile form. Desp ite early diagnosis and persistent therapy including dextromethorphan and sodium benzoate, two infants with the neonatal form deteriorated p rogressively and died at the age of 16 and 50 months, respectively, on ly one survived severely retarded with seizures, opisthotonus and spas tic quadriplegia. The serum concentrations of glycine decreased follow ing sodium benzoate treatment but cerebrospinal fluid/serum glycine ra tio remained elevated with no improvement in clinical outcome. The pat ient with the infantile form has been treated for over three years wit h dextromethorphan,and is now a severely retarded child without seizur e activity and continuous psychomotor development. Discussion: Symptom atic therapy including grand mal anticonvulsive drugs may be considere d in neonatal hyperglycinemia as there are irreversible prenatal brain damage and a lack of therapeutic success. Its positive tendency in ou r infantile case suggests that dextromethorphan therapy may provide a better outcome only in infantile forms. Since no effective treatment i s available, prenatal diagnosis in families at risk is of paramount im portance.