A neonate with nonketotic hyperglycinemia who experienced apnea, hiccups and tonic-clonic seizures on the first day of life is reported. The physical findings and laboratory tests including arterial blood gases were normal. However, serial blood and CSF aminoacid analyses demonstrated elevated glycine levels. Serum and CSF glycine levels were 1949 µmol/L and 415.5 µmol/L, respectively. (Normal serum level is 104-254 µmol/L and CSF level is 5 ± 2 µmol/L). The CSF/plasma glycine ratio was 0.11. Oral sodium benzoate and folic acid therapy was initiated. After two weeks of assisted ventilation and clinical improvement, the patient was discharged with a protein-restricted diet.

Keywords: nonketotic hyperglycinemia, newborn